ORNL-TM-9780-V2 by Jon Morrow

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OAK RIDGE NATIONAL LABORATORY

ORNL/TM-9780/V2

Nuclear Power Options Viability Study Volume 11, Reactor Concepts, Descriptions, and Assessments

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D. B. Trauger J. D. White J. T. Bell R. S. Booth H. I. Bowers J. C. Cleveland J. G. Delene Uri Gat D. C. Hampson T. Jenkins D. L. Moses P. E. Pasqua D. L. Phung 1. Spiewak R. E. Taylor

APPLIED TECHNOLOGY Any further distribution by any holder of this document or of the data therein to third parties representing foreign interests, foreign governments, foreign companies and subsidiaries, or foreign divisions of U.S. companies should be coordinated with the Deputy Assistant Secretary for Reactor Systems, Development, and Technology, U.S. Department of Energy. OPERATED 3Y MARTIN MARIETTA ENERGY SYSTEMS, INC. FOR THE UNITED STATES DEPARTMENT OF ENERGY

Released for annwncerr,ant in CfF. O&irrbulhXi h i ! C d !O p3r:;aigan:s the LMFSR pr9g:â&#x20AC;&#x2122;an. Olhers rewest from BsgT* DOE.

Printed in the United States of America. Available from the U S . Department of Energy Technical Information Center P.O. Box 62, Oak Ridge, Tennessee 37830

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To Addressees EXDLIX OF APPLIED TECH?;OLOG'i REPORTS

The purpose of this memorandum is to reiterate the necessity to protect AFplied Technology (AT) reports in the UC-79 (Liquid Metal Fast Breeder Reactors), UC-83 (Nuclear Converter Reactor Fuel Cycle Technology), and UC-86 (Consolidzted F u e l Reprocessing Program) categories from unauthorized release in order to preserve their trading value vis a vis international exchange agreenents. This memorandur, disseminated at the request of the Director of International Programs, Office of Support Prograz, Assistant Secretary for Nuclear Energy, provides farther guidance for the Field on this imjmrtant matter and serves as a reminder of the significance of the "Applied Techmlcgy" stat:;, shova below:

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ORNLflM-9780/V2 D i s t r i b u t i o n Category UC-79T (Applied Technology)

NUCLEAR POWER OPTIONS VIABILITY STUDY

VOLUME 11, REACTOR CONCEPTS, DESCRIPTIONS, AND ASSESSMENTS

D. J. J. R. H.

B. Trauger, E d i t o r D. White

T. S. I. J. C. J. G.

Bell Booth Bowers Cleveland Delene

U. G a t D. C. Hampson T. J e n k i n s ’ D. L. Moses P. E. Pasqua2 D. L. Phung3 I. Spiewak4 R. E. Taylor’ ’Tennessee V a l l e y A u t h o r i t y 2The U n i v e r s i t y of Tennessee 3 ~ r o f e s s i o n a lA n a l y s i s , I n c . 4 ~ o n s u latn t Date P u b l i s h e d

September 1986

Prepared f o r t h e O f f i c e of t h e A s s i s t a n t S e c r e t a r y f o r Nuclear Energy U.S. Department of Energy

P r e p a r e d by t h e OAK RIDGE NATIONAL LABORATORY Oak Ridge, Tennessee 37831 o p e r a t e d by MARTIN MARIETTA ENERGY SYSTEMS, I N C . for the U.S. DEPARTMENT OF ENERGY

PREFACE

The Nuclear Power Options V i a b i l i t y Study (NPOVS) was i n i t i a t e d a t t h e beginning of c a l e n d a r year 1984. The o b j e c t i v e of NPOVS w a s t o exp l o r e t h e v i a b i l i t i e s of s e v e r a l n u c l e a r o p t i o n s f o r t h i s c o u n t r y f o r e l e c t r i c power g e n e r a t i o n a f t e r t h e year 2000. The s t u d y emphasized t e c h n i c a l i s s u e s but a l s o c o n s i d e r e d i n s t i t u t i o n a l problems. Innovative r e a c t o r c o n c e p t s were i d e n t i f i e d which may be m a r k e t a b l e a t t h e t i m e when s t u d i e s show t h a t t h e demand f o r new e l e c t r i c a l energy c a p a c i t y w i l l increase significantly. These c o n c e p t s were c o n s i d e r e d w i t h emp h a s i s on c o s t , s a f e t y f e a t u r e s , o p e r a b i l i t y , and r e g u l a t i o n as w e l l as r e s e a r c h needs. The s t u d y i s r e p o r t e d i n f o u r volumes. Volume I i s a n e x e c u t i v e summary. T h i s r e p o r t , Volume 11, p r o v i d e s d e s c r i p t i o n s and a s s e s s m e n t s w i t h respect t o c r i t e r i a e s t a b l i s h e d i n t h e s t u d y of p o t e n t i a l n u c l e a r power p l a n t s which c o u l d be deployed e a r l y i n t h e n e x t century. Volume 111, Nuclear D i s c i p l i n e T o p i c s , p r o v i d e s s u p p o r t i n g a n a l y s e s ; and Volume I V i s a b i b l i o g r a p h y c o n t a i n i n g a p p r o x i m a t e l y 550 entries. A d e t a i l e d o u t l i n e c o v e r i n g a l l f o u r volumes i s given i n Appendix A. The s t u d y was i n i t i a t e d by Oak Ridge N a t i o n a l L a b o r a t o r y (ORNL), which, r e c o g n i z i n g t h e need f o r a broad base of knowledge and experi e n c e , engaged t h e Tennessee Valley A u t h o r i t y (TVA) and The U n i v e r s i t y of Tennessee t o p a r t i c i p a t e as p a r t n e r s . TVA c o n c e n t r a t e d i t s e f f o r t s on e v a l u a t i o n of t h e c o n c e p t s and on l i c e n s i n g . The U n i v e r s i t y of Tennessee a s s i s t e d i n t h e e v a l u a t i o n of c o n s t r u c t i o n c o s t s and p u b l i c opinion issues. Both i n s t i t u t i o n s c o n t r i b u t e d e x t e n s i v e l y t o t h e e v a l u a t i o n of i s s u e s and i n review of r e p o r t s . I n conducting t h e study, t h e a u t h o r s e x t e n s i v e l y c o n t a c t e d segments of t h e n u c l e a r i n d u s t r y f o r c u r r e n t i n f o r m a t i o n c o n c e r n i n g t h e c o n c e p t s s t u d i e d and f o r o t h e r v a l u e d a s sis t a n c e

Many of t h e problems e n c o u n t e r e d by t h e n u c l e a r i n d u s t r y are i n s t i t u t i o n a l i n n a t u r e and are r e l a t e d t o t h e way t h e u t i l i t y companies, d e s i g n e r s , c o n s t r u c t o r s , and r e g u l a t o r s are o r g a n i z e d and f u n c t i o n . Although t h i s s t u d y a t t e m p t e d t o i d e n t i f y t h o s e i n s t i t u t i o n a l f a c t o r s , i t h a s n o t a d d r e s s e d them i n a l l a s p e c t s . It w a s observed t h a t t h e i n s t i t u t i o n a l problems d e r i v e i n some measure from t e c h n i c a l a s p e c t s , which, i n t u r n , o r i g i n a t e a t l e a s t i n p a r t from t h e l a r g e s i z e , complexity, and e x a c t i n g r e q u i r e m e n t s f o r e x i s t i n g nuclear plants. Emphasis i n t h e s t u d y was p l a c e d on t e c h n i c a l a s p e c t s t h a t have potent i a l m e r i t and on improved d e s i g n c o n c e p t s t h a t may h e l p o r have promise of h e l p i n g t o a l l e v i a t e i n s t i t u t i o n a l problems. Institutional factors r e l a t e d t o market a c c e p t a n c e have a l s o been surveyed and s t u d i e d . Cons i d e r a t i o n of a d d i t i o n a l i n s t i t u t i o n a l f a c t o r s i s t h o u g h t t o be d e s i r a b l e , perhaps n e c e s s a r y , but i s beyond t h e scope of t h i s s t u d y . The s t u d y emphasized c r i t e r i a by which n u c l e a r power r e a c t o r s can be judged and which are thought t o be a p p r o p r i a t e , a t l e a s t i n p a r t , f o r

iii

j u d g i n g f u t u r e commercial v i a b i l i t y . O t h e r d e s i g n o r o p e r a t i o n a l needs t h a t are i m p o r t a n t but are more d i f f i c u l t t o q u a n t i f y are p r e s e n t e d as either essential or desirable characteristics. Several innovative r e a c t o r c o n c e p t s are d e s c r i b e d and e v a l u a t e d w i t h r e s p e c t t o t h e s e measures. R e l a t e d and g e n e r i c i n f o r m a t i o n on c o n s t r u c t i o n , economics, r e g u l a t i o n , s a f e t y and economic r i s k , waste t r a n s p o r t a t i o n and d i s p o s a l , and market a c c e p t a n c e which supplements t h e e v a l u a t i o n i s i n c l u d e d i n Volume 111. T h i s s t u d y d i f f e r s i n s e v e r a l r e s p e c t s from o t h e r s t u d i e s concerni n g t h e f u t u r e of n u c l e a r power i n t h e United States. The f i r s t i s t h e t i m e frame of i n t e r e s t . The NF'OVS e f f o r t w a s f o c u s e d on a t i m e frame a l i t t l e l a t e r t h a n most s t u d i e s , t h e y e a r s 2000 through 2010. For t h e n e a r term, e x i s t i n g Light-Water R e a c t o r (LWR) d e s i g n s , o r e v o l u t i o n a r y m o d i f i c a t i o n s t o them, would be t h e most l i k e l y n u c l e a r c h o i c e s i f t h e r e i s a s u f f i c i e n t demand f o r i n c r e a s e d e l e c t r i c a l g e n e r a t i n g c a p a c i t y . P r o j e c t i o n s by t h e e l e c t r i c i n d u s t r y i n d i c a t e t h a t new b a s e l o a d capacTherefore, it is probable t h a t i t y w i l l be needed b e f o r e t h e y e a r 2000. d e c i s i o n s t o o r d e r b a s e l o a d c a p a c i t y w i l l be made by 2000-2010 a n d , f u r t h e r m o r e , t h a t t h e r e a c t o r c o n c e p t s d i s c u s s e d i n t h i s r e p o r t have t h e p o t e n t i a l f o r competing w i t h e x i s t i n g LWR d e s i g n s o r c o a l - f i r e d p l a n t s at that time. For t h e more d i s t a n t f u t u r e , n u c l e a r p l a n t c o n c e p t s i n c o r p o r a t i n g more i n n o v a t i v e , i f n o t r e v o l u t i o n a r y , f e a t u r e s could b e t h e b e s t choices. A second a s p e c t making t h i s s t u d y d i f f e r e n t i s t h e l e v e l of t e c h Significantly n i c a l d e t a i l i n t h e e v a l u a t i o n of t h e s p e c i f i c d e s i g n s . more d e s i g n i n f o r m a t i o n was g e n e r a t e d by a l l t h e n u c l e a r d e s i g n e r s i n volved w i t h i n n o v a t i v e c o n c e p t s i n t h e l a s t t h r e e y e a r s , and much of t h i s i n f o r m a t i o n w a s made a v a i l a b l e t o NF'OVS. R e c o g n i t i o n h a s been g i v e n t o t h e s p e c i a l f e a t u r e s of each concept and t h u s t o t h e r o l e t h a t e a c h may a c h i e v e i n a mature n u c l e a r economy.

S y s t e m a t i c development of t h e i n f o r m a t i o n p r e s e n t e d i n t h i s r e p o r t was completed i n September 1985. Delays i n f u n d i n g and review have prevented timely p u b l i c a t i o n . An a t t e m p t h a s been made t o i n c l u d e new i n f o r m a t i o n where s u b s t a n t i a l changes i n programs o r d e s i g n s have o c c u r r e d , but i t has not been p o s s i b l e t o b r i n g t h e r e p o r t f u l l y up t o date. Subsequent developments and e v e n t s , p a r t i c u l a r l y t h e Chernobyl a c c i d e n t , may a l t e r some of t h e f i n d i n g s .

. CONTENTS Page ix xi 1-1 1-1

................................... 1.3 FOR CHAPTER 1 .............................. 2 . GROUND RULES AND CRITERIA .................................. 2.1 SIGNIFICANCE ................... 2.2 .............................................. 2.2.1 L i s t i n g of C r i t e r i a . E s s e n t i a l and R e l a t e d D e s i r a b l e C h a r a c t e r i s t i c s . and D i s c u s s i o n of T h e i r A p p l i c a t i o n s .......................... 2.3 2 .............................. 3. ........................................ 3.1 AND .................. 1.2

REPORT ORGANIZATION

1-2

REFERENCES

1-2

GROUND RULES AND THEIR

2-1 2-1

CRITERIA

2-2

REFERENCES FOR CHAPTER

CONCEPT EVALUATIONS CONCEPT SELECTION

3.2 3.3

CLASSIFICATION

............ LIGHT WATER REACTORS (LWRS) ........................... 3.3.1 PIUS ........................................... 3.3.1.1 D e s c r i p t i o n ........................... CONCEPT EVALUATION METHODS AND LIMITATIONS

3.3.1.2

2-7 3-1 3-1 3-2 3-2 3-2 3-2

Claims. Advantages. and Disadvantages Evaluated Against C r i t e r i a .

3.3.2

2-2

Essential

......... ............................. ............................. ...........................

3-13 3-14 3-14

.........

3-17

and D e s i r a b l e C h a r a c t e r i s t i c s 3.3.1.3 R&D Needs and Open Questions Evaluated S m a l l Advanced BWR 3.3.2.1 Description 3 3 2 2 C l a i m s . Pdvantages and Disadvantages Evaluated Against Criteria. E s s e n t i a l and D e s i r a b l e C h a r a c t e r i s t i c s R&D Needs and Open Questions 3.3.2.3 Evaluated

...

.............................

3-8

3-21

CONTENTS (CONTINUED)

3.4

LIQUID 3.4.1 3.4.2 3.4.3

3.4.4

................... ................................... .................................. ........................ ................................ ........................

METAL COOLED REACTORS (LMRs) Introduction Design Options, Challenges, and Tradeof f s Design D e s c r i p t i o n s 3.4.3.1 The Large S c a l e P r o t o t y p e Breeder (LSPB) 3.4.3.2 Sodium Advanced F a s t Reactor (SAFR) 3.4.3.3 Power R e a c t o r - I n h e r e n t l y S a f e Module (PRISM) Advantages and Disadvantages of t h e LMR Concepts with Regard t o t h e NPOVS Criteria and E s s e n t i a l Characteristics 3.4.4.1 General Overviews 3.4.4.2 Advantages of t h e LMR Concepts 3.4.4.3 Disadvantages of t h e LMR Concepts Research and Development Needs f o r t h e LMR Concepts 3.4.5.1 Introduction 3.4.5.2 Design-Specif i c R&D Requirements 3.4.5.3 General R&D Goals f o r t h e U.S. N a t i o n a l LMR Program

................................ ..................... ........ .............................. 3.4.5 ................................... .......................... ...... .................. 3.5 H I G H TEMPERATURE REACTORS (HTRs) ...................... 3.5.1 Design D e s c r i p t i o n s ............................ 3.5.2 C l a i m s , Advantages, and Disadvantages Evaluated Against C r i t e r i a , E s s e n t i a l and D e s i r a b l e C h a r a c t e r i s t i c s .................. 3.5.3 Modular HTR Research and Development Needs Evaluated ................................ 3.5.3.1 Base Technology ....................... 3.5.3.2 Applied Technology .................... 3.5.3.3 Design and Economic S t u d i e s ........... 3.6 REFERENCES FOR CHAPTER 3 .............................. 4. ACKNOWLEDGMENTS ............................................ APPENDIX A: BASIC OUTLINE FOR NUCLEAR POWER OPTIONS VIABILITY STUDY FINAL REPORT ...................... APPENDIX B: THE FOR SUPPLY AND DEMAND ........................................ APPENDIX C: DISCUSSION OF CONCEPTS INCLUDED FOR ASSESSMENT .................................... OUTLOOK

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A- 1

ELECTKICITY

B-1

NOT

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CONTENTS

Page APPENOIX D:

APPENDIX E:

APPENDIX F:

APPENDIX G:

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R&D GOALS AND S P E C I F I C REQUIREMENTS FOR L I Q U I D METAL REACTOR (LMR) CONCEPTS

D-1

L I Q U I D METAL REACTOR (LMR) REPROCESSING-REFABRICATION

E-1

FUEL EVALUATION

860 MW(e) LARGE HIGH TEMPERATURE GASCOOLED REACTOR (HTGR)

F-1

EVALUATION OF CLAIMS FOR THE MODULAR H I G H TEMPERATURE REACTOR (HTR)

G-1

vi i

ABSTRACT

The Nuclear Power Options V i a b i l i t y Study (NPOVS) i s r e p o r t i n g h e r e on t h e d e s c r i p t i o n and assessment of s e v e r a l s e l e c t e d i n n o v a t i v e r e a c t o r designs i n accordance with c r i t e r i a e s t a b l i s h e d i n t h e study. These c r i t e r i a are as f o l l o w s :

The c a l c u l a t e d r i s k t o t h e p u b l i c due t o a c c i d e n t s i s less t h a n o r e q u a l t o t h e c a l c u l a t e d r i s k a s s o c i a t e d w i t h t h e b e s t modern L i g h t Water R e a c t o r s (LWRS).

The p r o b a b i l i t y of e v e n t s l e a d i n g t o l o s s of i n v e s t m e n t i s less t h a n o r e q u a l t o l o W 4 per year (based on p l a n t c o s t ) .

The economic performance of t h e n u c l e a r p l a n t i s a t l e a s t e q u i v a l e n t t o t h a t f o r coal-fired plants. ( F i n a n c i a l g o a l s f o r t h e u t i l i t y are met, and busbar c o s t s are a c c e p t a b l e t o t h e p u b l i c u t i l i t y commissions.)

The d e s i g n of each p l a n t i s complete enough f o r a n a l y s i s t o show t h a t t h e p r o b a b i l i t y of s i g n i f i c a n t c o s t / s c h e d u l e o v e r r u n s i s a c c e p t a b l y low.

O f f i c i a l a p p r o v a l of a p l a n t d e s i g n must be g i v e n by t h e U.S. Nuclear R e g u l a t o r y Commission (NRC) t o a s s u r e t h e i n v e s t o r and t h e p u b l i c of a high p r o b a b i l i t y t h a t t h e p l a n t w i l l be l i c e n s e d on a t i m e l y b a s i s i f c o n s t r u c t e d i n accordance w i t h t h e approved d e s i g n .

For a new concept t o become a t t r a c t i v e i n t h e m a r k e t p l a c e , demons t r a t i o n of i t s r e a d i n e s s t o be d e s i g n e d , b u i l t , and l i c e n s e d and b e g i n o p e r a t i o n s on t i m e and a t p r o j e c t e d c o s t i s n e c e s s a r y .

The c r i t e r i a are supplemented by e s s e n t i a l c h a r a c t e r i s t i c s t h a t both a m p l i f y t h e c r i t e r i a and s u g g e s t a d d i t i o n a l q u a l i t i e s t h a t have a b e a r i n g on v i a b i l i t y . I n s e l e c t i n g t h e c o n c e p t s t o be s t u d i e d , t h e f o l l o w i n g t h r e e ground r u l e s were used :

The n u c l e a r p l a n t d e s i g n o p t i o n s h o u l d be developed s u f f i c i e n t l y t h a t an o r d e r could be p l a c e d i n t h e t i m e p e r i o d 2000 t h r o u g h 2010.

The d e s i g n o p t i o n should be economically c o m p e t i t i v e w i t h environmentally acceptable coal-fired plants.

The d e s i g n o p t i o n should p o s s e s s a high d e g r e e of p a s s i v e s a f e t y t o p r o t e c t t h e p u b l i c h e a l t h and p r o p e r t y and t h e owner's i n v e s t m e n t .

T h i s s t u d y l e d t o t h e c h o i c e of t h e f o l l o w i n g c o n c e p t s :

L i g h t Water R e a c t o r s (LWRs) 0

Liquid Metal R e a c t o r s (LMRs) 0

e 0

PIUS ( P r o c e s s I n h e r e n t Ultimate S a f e t y ) Promoted by ASEA-ATOM of Sweden Small BWR ( B o i l i n g Water Reactor) Promoted by General Electric (GE 1

PRISM (Power R e a c t o r I n t r i n s i c a l l y S a f e Nodule) The advanced concept s u p p o r t e d by DOE SAFR (Sodium Advanced F a s t R e a c t o r ) The Rockwell I n t e r n a t i o n a l ( R I ) advanced concept s u p p o r t e d by DOE LSPB (Large-Scale P r o t o t y p e Breeder) The Electric Power Res e a r c h I n s t i t u t e - C o n s o l i d a t e d Management O f f i c e (EPRI-CoMO) conc e p t s u p p o r t e d by EPRI and DOE

High Temperature R e a c t o r (HTR) 0

Side-by-Side Modular The c o r e and steam g e n e r a t o r i n s e p a r a t e s t e e l v e s s e l s i n a side-by-side c o n f i g u r a t i o n . The concept i s s u p p o r t e d by DOE and promoted by Gas-Cooled Reactor A s s o c i a t e s (GCRA) and i n d u s t r i a l firms.

These c o n c e p t s are judged t o be p o t e n t i a l l y a v a i l a b l e in t h e chosen t i m e p e r i o d , are e s t i m a t e d by t h e i r promoters t o be e c o n o m i c a l l y compet i t i v e w i t h c o a l - f i r e d power p l a n t s , and have v a r y i n g d e g r e e s of p a s s i v e In a l l cases, t h e d e s i g n s are t o o p r e l i m i n a r y f o r a safety attributes. complete and d e f i n i t i v e a s s e s s m e n t , but e a c h i s b e l i e v e d t o have potential for a s i g n i f i c a n t f u t u r e role. The Advanced Pressurized-Water Rea c t o r (APWR), t h e Advanced Boiling-Water R e a c t o r (ABWR), and t h e l a r g e HTR are recognized as v i a b l e systems which could meet electric power They are n o t ing e n e r a t i n g needs p r i o r t o o r f o l l o w i n g t h e y e a r 2000. cluded i n t h i s s t u d y e x c e p t f o r r e f e r e n c e because t h e y do n o t f u l l y meet t h e t h i r d ground r u l e and because t h e y a l r e a d y have been t h e s u b j e c t of e x t e n s i v e s t u d y by i n d u s t r y .

SUMMARY OF FINDINGS

The c r i t e r i a and t h e e s s e n t i a l and d e s i r a b l e c h a r a c t e r i s t i c s d e s c r i b e d i n Chapter 2 are p r e s e n t e d as u s e f u l g u i d e s t o t h e s e l e c t i o n and e v a l u a t i o n of c u r r e n t and f u t u r e n u c l e a r r e a c t o r c o n c e p t s . The c r i t e r i a were developed e a r l y i n t h e s t u d y and have been s u b j e c t e d t o e x t e n s i v e review and r e f i n e m e n t . The c r i t e r i a s e r v e as g u i d e s f o r t h e e v a l u a t i o n s of c o n c e p t s p r e s e n t e d i n t h i s r e p o r t . Most advanced r e a c t o r c o n c e p t s are smaller t h a n p r e s e n t LwRs; t h e r e f o r e , they s u f f e r t h e d i s a d v a n t a g e , whether r e a l o r p e r c e i v e d , a s s o c i a t e d w i t h economy of scale. This d i s a d v a n t a g e i s claimed t o be o f f s e t o r compensated f o r i n v a r y i n g d e g r e e s through an improved match w i t h load growth, r e d u c t i o n i n c a p i t a l r i s k , i n c r e a s e d shop f a b r i c a t i o n , s h o r t e r construction t i m e , increased standardization, design simplificat i o n , and s i m p l e r c o n s t r u c t i o n management r e q u i r e m e n t s . Licensing a l s o A s u b s t a n t i a l problem i n a c h i e v i n g t h e s e compensamay be s i m p l i f i e d . t i o n s d e r i v e s from t h e need f o r a l a r g e front-end investment f o r c e r t a i n of t h e s e f e a t u r e s . Automated shop f a b r i c a t i o n , i n p a r t i c u l a r , may req u i r e a s u b s t a n t i a l backlog of o r d e r s t o be economically f e a s i b l e . Nuclear p l a n t s t a n d a r d i z a t i o n i s widely viewed as an i m p o r t a n t g o a l f o r viability. To be c o n c i s e i n t h i s summary, we have assumed t h a t t h e r e a d e r i s f a m i l i a r w i t h t h e concepts. I f n o t , t h e concept d e s c r i p t i o n s should be read f i r s t . The claims, a d v a n t a g e s , d i s a d v a n t a g e s , and i m p o r t a n t development needs w i l l be summarized i n t h e o r d e r i n which t h e c o n c e p t s appear i n t h e r e p o r t . It must be n o t e d t h a t each of t h e s e c o n c e p t s i s c u r r e n t l y i n d e s i g n development. The d e s c r i p t i o n s and a s s e s s m e n t s of t h i s s t u d y r e f l e c t t h e s t a t u s f o r each as of September 1985 e x c e p t t h a t some u p d a t i n g h a s been done where i n f o r m a t i o n was r e a d i l y a v a i l a b l e . The r e a d e r must r e c o g n i z e t h a t f u r t h e r development i s e x p e c t e d t o change d e s i g n f e a t u r e s and t h u s t o a f f e c t t h e c o n c l u s i o n s from f u t u r e e v a l u a t i o n s .

A l l of t h e c o n c e p t s f o r t h e s t u d y a p p e a r t o be p o t e n t i a l l y v i a b l e , but t h e a v a i l a b l e i n f o r m a t i o n h a s been i n s u f f i c i e n t t o assess f u l l y t h e i r economic c o m p e t i t i v e n e s s . F i n d i n g s f o r t h e c o n c e p t s are summarized here.

PIUS The b a s i c d e s i g n premise of t h i s concept i s t o a c h i e v e a very high d e g r e e of p a s s i v e s a f e t y w i t h r e s p e c t t o equipment f a i l u r e , o p e r a t o r err o r , and e x t e r n a l t h r e a t s . The l a r g e pool of b o r a t e d water, which can e n t e r t h e c o r e w i t h o u t mechanical, e l e c t r i c a l , o r o p e r a t o r a c t i o n , i s t o p r o v i d e both shutdown and seven days of p a s s i v e c o o l i n g f o r decay h e a t removal. These claims appear t o be j u s t i f i e d , a l t h o u g h q u e s t i o n s remain c o n c e r n i n g t h e s a f e t y of f u e l and equipment h a n d l i n g o p e r a t i o n s w i t h i n t h e pool. The a v a i l a b i l i t y of w a t e r f o r i n t r o d u c t i o n t o t h e pool a f t e r s e v e n days i s s i t e dependent but p o t e n t i a l l y v i a b l e . Overall, the

concept a p p e a r s t o be l i c e n s a b l e w i t h o u t major r e d e s i g n , assuming t h a t t h e NRC w i l l a c c e p t a r e a c t o r w i t h no c o n t r o l rods. The f e a t u r e s t h a t promote s a f e t y a l s o appear a p p l i c a b l e t o p r o t e c t i o n of t h e investment. ASEA-ATOM claims t h a t t h e p l a n t can be economically c o m p e t i t i v e w i t h coal-fired plants. This may depend on f u r t h e r e v a l u a t i o n of t h e i d e n t i f i e d problems t h a t follow. The steam g e n e r a t o r l o c a t e d i n s i d e t h e P r e s t r e s s e d Concrete Press u r e Vessel (PCPV) i s of a d i f f i c u l t d e s i g n w i t h r e s p e c t t o maintenance. This and t h e problems of h a n d l i n g f u e l and equipment deep (30 m) i n t h e pool r e q u i r e c a r e f u l d e s i g n and d e t a i l e d assessment and are cons i d e r e d a d i s a d v a n t a g e w i t h respect t o p o t e n t i a l a v a i l a b i l i t y of t h e plant. Management of r e f u e l i n g a p p e a r s d i f f i c u l t f o r t h e t h r e e - c o r e d e s i g n i f t h e r e f u e l i n g sequence becomes o u t of phase. Development and t e s t i n g needs i n c l u d e f u r t h e r d e m o n s t r a t i o n of f l u i d i n t e r f a c e s t a b i l i t y , e x t e n s i v e s t u d y and t e s t i n g of steam genera t o r modules, thorough t e s t i n g of underwater f u e l and equipment h a n d l i n g systems, steam flow and p r e s s u r i z e r s t a b i l i t y f o r t h e multimodular des i g n , thermal i n s u l a t i o n development and t e s t i n g , and d e m o n s t r a t i o n of t h e PCPV d e s i g n , p a r t i c u l a r l y f o r t h e t o p c l o s u r e . Small Advanced BWR T h i s r e a c t o r o b v i o u s l y d e r i v e s advantage from i t s many o p e r a t i n g s i m i l a r i t i e s t o e x i s t i n g BWRs. The g r a v i t y - f e d Emergency Core Cooling System (ECCS) a p p e a r s w e l l conceived and a d e q u a t e t o p r o v i d e shutdown c o o l i n g f o r up t o t h r e e days, a l t h o u g h i t s r e l i a b i l i t y i s dependent on a r e l a t i v e l y u n t r i e d f a i l - o p e n valve. A r e l i a b l e s i t e - d e p e n d e n t s u p p l y of a d d i t i o n a l c o o l i n g water would be r e q u i r e d beyond t h e t h r e e days. Opera t o r t r a i n i n g should be s t r a i g h t f o r w a r d s i n c e t h e b a s i c o p e r a t i o n i s s i m i l a r t o t h a t of e x i s t i n g BWR p l a n t s . A first-of-a-kind s a f e t y test and d e m o n s t r a t i o n whereby t h e p l a n t would l a t e r be used f o r power prod u c t i o n may be p r a c t i c a l and a d e q u a t e f o r t h i s concept. Cost c o m p e t i t i v e n e s s i s d i f f i c u l t t o assess a t t h i s e a r l y s t a g e of d e s i g n development. L i c e n s i n g r e q u i r e m e n t s , a l t h o u g h not thought to be Model p a r t i c u l a r l y d i f f i c u l t , have n o t y e t been a d d r e s s e d completely. t e s t i n g f o r t h e g r a v i t y - d r a i n ECCS, steam i n j e c t o r t e s t i n g , and t h e r m a l The d e p r e s s u r i z a t i o n h y d r a u l i c and seismic a n a l y s e s must be thorough. v a l v e a l s o r e q u i r e s d e s i g n , development, and t e s t i n g .

LMR Concepts

The LSPB i s an e v o l u t i o n of p r e v i o u s L i q u i d Metal F a s t Breeder It i n c l u d e s s e v e r a l i n n o v a t i o n s t o reduce capReactor (LMFBR) d e s i g n s . i t a l c o s t s and t o enhance s a f e t y . The l a t t e r i n c l u d e d i v e r s e and independent r e a c t o r shutdown and d e d i c a t e d decay h e a t removal systems. Although t h i s d e s i g n o f f e r s lower c o s t s , t h e s e f e a t u r e s a r e y e t t o be evaluated fully with respect to construction methods and

x ii

l i c e n s a b i l i t y . The LSPB a p p e a r s a t t r a c t i v e i n o f f e r i n g economy of s c a l e and i n c r e a s e d p a s s i v e s a f e t y . S i n c e t h e PRISM and SAFR c o n c e p t s are under development i n a DOE program and are a t a p r e l i m i n a r y s t a g e , t h e y w e r e a s s e s s e d p r i m a r i l y i n LMR c o n c e p t s b e n e f i t from t h e i n h e r e n t LMR f e a t u r e s of low common. system p r e s s u r e and h i g h t h e r m a l c o n d u c t i v i t y of t h e l i q u i d metal (sodium) c o o l a n t . These f e a t u r e s p e r m i t t h e d e s i g n of primary c o n t a i n ment pool c o n c e p t s w i t h r e l i a b l e p a s s i v e n a t u r a l c o n v e c t i o n decay h e a t The smaller modular c o n c e p t s p r o v i d e t h e removal t o a t m o s p h e r i c a i r . p o t e n t i a l f o r t e s t i n g of t h e c o r e s t a b i l i t y f o r c o n d i t i o n s t h a t might r e s u l t from r e a c t i v i t y i n c r e a s e s o r from l o s s of flow of primary sodium. I n t h i s r e s p e c t , smaller r e a c t o r s g e n e r a l l y have a n a d v a n t a g e o v e r t h e l a r g e r LMRs. Although t h e h y p o t h e t i c a l c o r e d i s r u p t i v e accid e n t (HCDA) i s claimed t o be i n c r e d i b l e by t h e p r o p o n e n t s , t h e case f o r d i s r e g a r d i n g t h i s a c c i d e n t i s y e t t o be approved by t h e NRC. If the C l i n c h R i v e r Breeder Reactor (CRBR) can be t a k e n as a p r e c e d e n t , t h e n i t would be r e a s o n a b l e t o e x p e c t t h a t a HCDA would be a beyond d e s i g n b a s i s e v e n t (BDBE). Acknowledging p a s s i v e accommodation of HCDAs could s i g n i f i c a n t l y r e d u c e d e s i g n c o m p l e x i t y , f a c i l i t a t e l i c e n s i n g , and improve public acceptance. R e l i a b l e c o n t r o l rod shutdown s y s t e m s , f e e d b a c k r e s p o n s e from t e m p e r a t u r e i n c r e a s e s , and t h e r e s u l t i n g t h e r m a l e x p a n s i o n are i m p o r t a n t s a f e t y f e a t u r e s . Although c o n t a i n m e n t s are p r o v i d e d , c a r e f u l d e s i g n and perhaps t e s t i n g w i l l be r e q u i r e d t o e n s u r e t h a t a i r o x i d a t i o n of t h e sodium cannot occur. Where primary b o u n d a r i e s and cont a i n m e n t s are i n c l o s e p r o x i m i t y , t h e y must be w e l l p r o t e c t e d from ext e r n a l t h r e a t s t h a t could b r e a c h b o t h e n c l o s u r e s . An i m p o r t a n t advantage of t h e LMR i s t h e e x t e n s i v e o p e r a t i n g exp e r i e n c e a v a i l a b l e from t h e F a s t Flux T e s t F a c i l i t y (FFTF), t h e Experim e n t a l Breeder R e a c t o r - I 1 (EBR-11) and t h e European and J a p a n e s e plants. However, l i t t l e of t h i s e x p e r i e n c e i s i n t h e U.S. u t i l i t y b a s e , and t h e l o s s of t h e C l i n c h River Breeder R e a c t o r (CRBR) a l s o slowed t h e pace of development of LMRS i n t h i s c o u n t r y . Although i t a p p e a r s p o s s i b l e t o d e s i g n , c o n s t r u c t , and o p e r a t e a d e m o n s t r a t i o n p l a n t and t o r e a c h c o m m e r c i a l i z a t i o n w i t h i n t h e 2000-2010 t i m e scale, i t would require an e a r l y dedication t o the task. The a v a i l a b i l i t y of r e l a t e d e x p e r i e n c e , t h e s i m p l i c i t y of t h e proposed d e s i g n s , and t h e p a s s i v e f e a t u r e s mentioned above s t r o n g l y s u g g e s t An obvious long-term t h a t t h e l i c e n s i n g of LMRs should be a c h i e v a b l e . a d v a n t a g e of t h e LMR i s i t s p o t e n t i a l f o r b r e e d i n g and t h e r e b y c r e a t i n g a n e s s e n t i a l l y u n l i m i t e d e x t e n s i o n of uranium f u e l r e s o u r c e s . Although t h i s i s n o t a n immediate o b j e c t i v e of t h e c u r r e n t program, i t s h o u l d n o t be overlooked. H i s t o r i c a l l y , M R c o n c e p t s have had h i g h e r c a p i t a l c o s t f a c t o r s t h a n LWRs. T h i s c o s t e x p e r i e n c e i s m a n i f e s t e d i n European as w e l l as U.S. d e s i g n s . Although t h e c u r r e n t c o n c e p t s a d d r e s s t h i s i s s u e , i t is as y e t not a d e q u a t e l y r e s o l v e d . The l o n g l i f e c o r e d e s i g n s r e p r e s e n t one approach t o o v e r a l l c o s t r e d u c t i o n . Another d i s a d v a n t a g e i s t h e r e q u i r e m e n t f o r e n r i c h e d uranium o r plutonium as t h e s t a r t i n g f u e l . The

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former i s e s s e n t i a l l y a s s u r e d by p r e s e n t U. S. e n r i c h m e n t programs s i n c e the required production capacity e x i s t s . The l a t t e r i s a t an e a r l y s t a g e of development f o r a c c e p t a b l e f u e l r e p r o c e s s i n g p l a n t s i n t h i s c o u n t r y , a l t h o u g h c o n s i d e r a b l e e x p e r i e n c e e x i s t s abroad and i n m i l i t a r y facilities. O t h e r c o u n t r i e s o f f e r t h e p r o s p e c t f o r p u r c h a s e of plutonium, b u t t h i s i s u n l i k e l y t o be an a c c e p t a b l e c o n t i n u i n g s o u r c e . Once-through c y c l e s are n o t a d e q u a t e f o r long-term n u c l e a r energy v i a b i l i t y ; t h e r e f o r e , r e p r o c e s s i n g remains an i m p o r t a n t o b j e c t i v e f o r f u t u r e TMR c o n c e p t s . The p o t e n t i a l u s e of i n t e g r a l f a s t r e a c t o r s which would be c o l l o c a t e d w i t h t h e s u p p o r t i n g f u e l r e p r o c e s s i n g and r e f a b r i c a t i o n f a c i l i t y f a c e s s i g n i f i c a n t i n s t i t u t i o n a l problems f o r o p e r a t i o n . Development needs i n c l u d e advanced c o r e d e s i g n and approved n e u t r o n c o u n t i n g s y s t e m s , improved s h i e l d i n g , and s e l f - a c t u a t e d shutdown systems. T e s t i n g of h e a t removal systems i s an obvious r e q u i r e m e n t . Depending upon t h e c h o i c e of i n i t i a l f u e l , t h e f u e l c y c l e r e q u i r e m e n t s may be e x t e n s i v e . The use of metal f u e l s , which o f f e r some s a f e t y and opera t i o n a l a d v a n t a g e s , r e q u i r e s an e x t e n s i v e f u e l development and t e s t i n g program. Concepts under c o n s i d e r a t i o n s h o u l d b e n e f i t s u b s t a n t i a l l y from d e m o n s t r a t i o n r e a c t o r t e s t i n g ; however, w c a u t i o n a g a i n s t o v e r l y o p t i m i s t i c e x p e c t a t i o n s from t h i s approach. I n d e e d , v a l u a b l e e x p e r i e n c e c a n be g a i n e d , and a n a l y t i c a l t e c h n i q u e s can be t e s t e d . However, many d i s turbances (such as the effects of severe seismic events, external inter-

f e r e n c e w i t h a i r c o o l i n g , and s a b o t a g e ) cannot be t e s t e d and would require analysis f o r evaluation. Such a n a l y s i s would i n c l u d e p r o b a b i l i s t i c r i s k a s s e s s m e n t s and s i m u l a t i o n s u s i n g models v e r i f i e d a g a i n s t d a t a from smaller scale e x p e r i m e n t s . A more d e s i r a b l e and c o n v i n c i n g a p p r o a c h w i t h r e s p e c t t o u t i l i t y a c c e p t a n c e may be t o c o n s t r u c t and o p e r a t e a d e m o n s t r a t i o n o r p r o t o t y p e p l a n t based on a n a d e q u a t e program of a n a l y s i s , component development, and t e s t i n g and d e s i g n .

Modular HTR Side-bv-Side

ConceDts

A h i g h d e g r e e of p u b l i c p r o t e c t i o n i s a c h i e v e d through t h e avoidance of f u e l damage by v i r t u e of a c a p a b i l i t y f o r e x t e n d e d a f t e r h e a t removal through t h e v e s s e l w a l l by c o n v e c t i o n , c o n d u c t i o n , and thermal r a d i a t i o n without o p e r a t o r , mechanical, o r electrical intervention. T h i s advantage i s made p o s s i b l e by t h e v e r y high t e m p e r a t u r e c a p a b i l i t y of t h e f u e l , i n c l u d i n g r e t e n t i o n of f i s s i o n p r o d u c t s and t h e slow t h e r m a l r e s p o n s e of t h e c o r e , which e l i m i n a t e s t h e need f o r a f a s t a c t i n g shutdown system. The same p r o t e c t i o n a p p l i e s t o t h e p r o b a b i l i t y of e v e n t s l e a d i n g t o a l o s s of i n v e s t m e n t . The “low-enriched‘‘ f u e l i s an a d v a n t a g e i n p r o l i f e r a t i o n r e s i s t a n c e b u t r e q u i r e s enrichment beyond t h a t f o r a c o n v e n t i o n a l WR. The p o t e n t i a l f o r p r o d u c i n g high-tempera t u r e p r o c e s s h e a t i s a long-term a d v a n t a g e .

D i s a d v a n t a g e s i n c l u d e a p o t e n t i a l l y high o v e r n i g h t c a p i t a l c o s t . Most, i f n o t a l l , HTR d e s i g n s have p r o j e c t e d c a p i t a l c o s t s h i g h e r t h a n t h o s e of l a r g e LWR r e a c t o r s . This must be overcome by h i g h a v a i l a b i l i t y and h i g h c a p a c i t y f a c t o r s , shop f a b r i c a t i o n , reduced c o s t s f o r t h e b a l a n c e of p l a n t , and low f u e l c y c l e c o s t s .

x iv

A d i s i n c e n t i v e f o r t h e a p p l i c a t i o n of an HTR i n t h e United S t a t e s i s t h e poor performance t o d a t e of t h e F o r t S t . V r a i n r e a c t o r . However, t h e d i f f i c u l t i e s w i t h t h i s r e a c t o r are unique t o i t s equipment and are not common w i t h t h e new c o n c e p t . I n many ways, t h e MHTR d e s i g n c a n b e n e f i t from t h e l e s s o n s l e a r n e d a t F o r t S t . Vrain. A l s o , t h e performance of t h e Peach Bottom Unit 1 r e a c t o r i n t h e United States and t h a t of t h e A r b e i t s g e m e i n s c h a f t Versuchs-Reaktor (AVR) i n Germany h a s been s a t i s f a c t o r y . S i n c e t h e Thorium High Temperature Reactor (THTR3 0 0 ) i n Germany i s t h e l a t e s t HTR t o s t a r t o p e r a t i o n , i t s o p e r a t i n g performance i s i m p o r t a n t t o watch.

The small b a s e of o p e r a t i n g e x p e r i e n c e i n t h e United S t a t e s sugg e s t s an i m p o r t a n t need f o r a s u c c e s s f u l MHTR d e m o n s t r a t i o n p l a n t . Because of t h e ruggedness and r e s i l i e n c y of t h e f u e l and t h e i n h e r e n t l y slow t i m e r e s p o n s e f o r t h e r m a l e x c u r s i o n s , i t seems p o s s i b l e t h a t a d e m o n s t r a t i o n p l a n t could be used e x t e n s i v e l y f o r e x p e r i m e n t a t i o n i n power s a f e t y and o p e r a b i l i t y and could l a t e r s e r v e as a f i r s t - o f - a - k i n d plant. However, s i n c e t h e d e s i g n e x p e r i e n c e i s a l s o l i m i t e d , i t i s q u i t e p o s s i b l e t h a t a s t a n d a r d i z e d p l a n t d e s i g n might b e n e f i t from t h e e x p e r i e n c e of t h e d e m o n s t r a t i o n . Development needs i n c l u d e t h e d e t e r m i n a t i o n of f i s s i o n p r o d u c t ret e n t i o n by t h e f u e l c o a t i n g s , g r a p h i t e , and metal s u r f a c e s under hypot h e t i c a l extreme a c c i d e n t c o n d i t i o n s . Although a c c e p t a b l e g r a p h i t e i s a v a i l a b l e f o r f a b r i c a t i o n of f u e l e l e m e n t s and r e f l e c t o r b l o c k s , s t a t i s t i c a l d a t a are needed t o b e t t e r u n d e r s t a n d i t s widely v a r i a b l e propert i e s as a b a s i s f o r improvement of t h e b a s i c s t r u c t u r e and t o o b t a i n longer lifetimes. S t r u c t u r a l materials development needs r e l a t e t o o b t a i n i n g p h y s i c a l p r o p e r t y d a t a t o s a t i s f y code r e q u i r e m e n t s , i n c l u d i n g t h e e f f e c t s of n e u t r o n i r r a d i a t i o n on p h y s i c a l p r o p e r t i e s . Another i m p o r t a n t area of development i s t e s t i n g of key components under a c t u a l conditions. T h i s t e s t i n g i s e s p e c i a l l y i m p o r t a n t i n t h e case of t h e c i r c u l a t o r and r e f u e l i n g system t o a s s u r e h i g h a v a i l a b i l i t y . Materials c o r r o s i o n t e s t i n g f o r v a r i o u s p r o j e c t e d i m p u r i t y l e v e l s i n t h e helium would a l s o be d e s i r a b l e but p r o b a b l y is n o t a r e q u i r e m e n t .

1 1

INTRODUCTION

BACKGROUND

The Nuclear Power Options V i a b i l i t y Study (NPOVS) w a s begun a t Oak Ridge N a t i o n a l L a b o r a t o r y (ORNL) i n J a n u a r y 1984 t o assess s e l e c t e d nuc l e a r power o p t i o n s w i t h r e s p e c t t o v i a b i l i t y and t o i d e n t i f y new d i r e c t i o n s f o r i n d u s t r y , r e g u l a t i o n , and r e s e a r c h . For t h e f i r s t f i v e months, t h e s t u d y was funded through t h e ORNL D i r e c t o r ' s d i s c r e t i o n a r y fund. S i n c e June of 1984, t h e U.S. Department of Energy (DOE) h a s funded t h e program d i r e c t l y . The Tennessee V a l l e y A u t h o r i t y (TVA) and The U n i v e r s i t y of Tennessee (UT) have been working w i t h ORNL i n t h i s s t u d y ; TVA has used i t s awn f u n d s , w h i l e UT has been funded by ORNL through s u b c o n t r a c t s . The i n f o r m a t i o n on which t h i s r e p o r t i s based has been g a t h e r e d from t h e open l i t e r a t u r e , as w e l l as from r e a c t o r d e s i g n o r g a n i z a t i o n s , v e n d o r s , r e s e a r c h and development (R&D) i n s t i t u t i o n s , u t i l i t y companies and t h e DOE. Proprietary information or other information received with r e s t r i c t i o n s has been c o n s i d e r e d i n t h e assessment b u t i s n o t d i s p l a y e d per se. I n a r e c e n t s t u d y by t h e Atomic I n d u s t r i a l Forum, Inc. (AIF), t h e f o l l o w i n g s t a t e m e n t i s made i n t h e E x e c u t i v e Summary: "Nuclear power cannot a t t h i s t i m e be c o n s i d e r e d a v i a b l e o p t i o n on which t o base new The s t u d y p o i n t s o u t t h a t e l e c t r i c g e n e r a t i n g c a p a c i t y i n t h e U.S."l o n l y h a l f as much n u c l e a r c a p a c i t y w i l l be c o n s t r u c t e d by 1986 as comSince 1972, 108 pared t o t h a t which w a s p r o j e c t e d o n l y t e n y e a r s ago. p l a n t s have been c a n c e l l e d ; no new o r d e r s have been p l a c e d s i n c e 1978. It i s s i g n i f i c a n t t o n o t e t h a t t h e r e were no new l a r g e p l a n t s of any t y p e o r d e r e d i n 1984. O t h e r s have a d d r e s s e d p r o j e c t e d needs f o r e l e c t r i c energy and i n d i c a t e d a r e q i ed i n c r e a s e i n b a s e l o a d c a p a c i t y Y- ( S e e a l s o Appendix B ) . by t h e y e a r 2000 o r soon t h e r e a f t e r .

S e v e r a l r e c e n t s t u d i e s have c o n s i d e r e d t h e i s s u e of n u c l e a r power Most of these e i t h e r (1) concern themselves w i t h v i a b i l i t y . 7-9 e v a l u a t i o n s of l a r g e Light-Water R e a c t o r s (LWRS) o r ( 2 ) assume t h a t development of a new brand of p a s s i v e l y s a f e r e a c t o r d e s i g n s would l e a d t o a second wave of n u c l e a r r e a c t o r o r d e r s . The arguments are c e n t e r e d around t h e assumptions t h a t e i t h e r ( 1 ) LWR e v o l u t i o n s could p r o v i d e by f a r t h e most c o s t - e f f e c t i v e way of meeting t h e n a t i o n ' s needs o r ( 2 ) i n h e r e n t l y safe d e s i g n s could l e a d t o d e c r e a s e s i n l i c e n s i n g t i m e and c o s t s , be made s i m p l e r and cheaper t h a n e x i s t i n g LWRs, and be more a c c e p t a b l e t o t h e p u b l i c and t h e i n v e s t o r . T h i s s t u d y has emphasized t e c h n i c a l d e t a i l i n t h e e v a l u a t i o n of t h e s p e c i f i c designs. I n s t i t u t i o n a l f a c t o r s are r e c o g n i z e d as v e r y import a n t , even t o t h e e x t e n t of overshadowing t e c h n i c a l i s s u e s , and are t h e r e f o r e i n c l u d e d i n t h e c r i t e r i a chosen f o r e v a l u a t i n g t h e c o n c e p t s . However, t h e p r i n c i p a l t h r u s t of t h i s series of r e p o r t s i s on t e c h n i c a l i s s u e s t h a t have merit i n t h e i r own r i g h t and p a r t i c u l a r l y on t h o s e t h a t may a l l e v i a t e i n s t i t u t i o n a l problems. For example, added p a s s i v e s a f e t y may s i m p l i f y r e g u l a t i o n . S e v e r a l i n s t i t u t i o n a l f a c t o r s are c o n s i d e r e d

1-1

1-2 g e n e r i c a l l y f o r t h e r e a c t o r c o n c e p t s i n c h a p t e r s of Volume 111. S i g n i f i c a n t new d e s i g n c o n c e p t s have been g e n e r a t e d i n r e c e n t y e a r s by n u c l e a r d e s i g n e r s i n v o l v e d w i t h i n n o v a t i v e approaches. This i n f o r m a t i o n c o n s t i t u t e s a s u b s t a n t i a l p o r t i o n of t h e s u b j e c t s c o n s i d e r e d i n t h i s volume. A t t e n t i o n i s g i v e n i n t h e s t u d y t o s a f e t y and r e l i a b i l i t y , c o s t , l i c e n s i n g , and development needs as w e l l as t o t h e s p e c i a l f e a t u r e s of e a c h concept. The NPOVS program has proceeded i n t h e f o l l o w i n g s t e p s : (1) a l i t e r a t u r e s e a r c h and development of a b i b l i o g r a p h y ; ( 2 ) development of c r i t e r i a f o r e v a l u a t i o n of n u c l e a r p l a n t d e s i g n s and p l a n s ; ( 3 ) e v a l u a t i o n of s e l e c t e d d e s i g n c o n c e p t s u s i n g t h e s e c r i t e r i a as a g u i d e ; and ( 4 ) recommendations f o r areas of R&D t o reduce u n c e r t a i n t i e s i n t h e v i a b i l i t i e s of o p t i o n s . The approach used i n e v a l u a t i o n w a s t o compile d e t a i l e d i n f o r m a t i o n on t h e v a r i o u s r e a c t o r c o n c e p t s of i n t e r e s t , s y n t h e s i z e t h a t i n f o r m a t i o n i n accordance w i t h s p e c i f i c t e c h n i c a l areas, d e v e l o p an u n d e r s t a n d i n g of how d e s i g n f e a t u r e s i n f l u e n c e t h e o v e r a l l c o s t of g e n e r a t i n g power, and c o n s i d e r how changes i n t h e d e s i g n might accomplish improved economic performance and a c c e p t a n c e by r e g u l a t o r s and t h e p u b l i c . I n a d d i t i o n t o t e c h n i c a l e v a l u a t i o n , a s s e s s m e n t s were a l s o made of t h e v a r i o u s n o n t e c h n i c a l f a c t o r s t h a t i n f l u e n c e commercial use: f o r example, r e g u l a t o r y r e q u i r e m e n t s , i n d u s t r y p e r s p e c t i v e s on f u t u r e t e c h n o l o g i e s , p u b l i c a c c e p t a n c e , e l e c t r i c power growth needs, and economic c o n d i t i o n s .

1 2

REPORT ORGANIZATION

T h i s r e p o r t i s o r g a n i z e d i n t o f o u r volumes. Volume I i s t h e Execut i v e Summary. l o Volume 11, Reactor Concepts, D e s c r i p t i o n s , and Assessments ( t h i s volume) p r i m a r i l y d e s c r i b e s and e v a l u a t e s t h e v a r i o u s c o n c e p t s i n accordance w i t h a chosen methodology. The a d v a n t a g e s and d i s a d v a n t a g e s as w e l l as needs f o r f u r t h e r R&D of each concept are described. Volume 111, Nuclear D i s c i p l i n e T o p i c s , l 1 d e a l s w i t h g e n e r i c d i s c i p l i n a r y i s s u e s r e l e v a n t t o n u c l e a r v i a b i l i t y and p r o v i d e s a more d e t a i l e d d i s c u s s i o n of i s s u e s . C o n s t r u c t i o n , economics, r e g u l a t i o n , s a f e t y and economic r i s k , n u c l e a r waste t r a n s p o r t a t i o n and d i s p o s a l , and market a c c e p t a n c e are c o n s i d e r e d b o t h i n d i v i d u a l l y and as i n t e r related. Acceptance of n u c l e a r energy by u t i l i t i e s , r e g u l a t o r s and t h e p u b l i c and i n s t i t u t i o n a l needs t o r e v i t a l i z e t h e n u c l e a r o p t i o n are d i s cussed. Volume N i s a comprehensive b i b l i o g r a p h y . l 2

1.3

REFERENCES FOR CHAPTER 1

Nuclear Power i n America's F u t u r e , Atomic I n d u s t r i a l Forum, New York, New York, June 1984.

The F u t u r e of E l e c t r i c Power i n America: Economic Supply f o r Economic Growth, DOE/PE-0045, U. S. Department of Energy, Washington, D.C., June 1983.

Inc.,

J. Skeer and D. Meyer, ' h o V i e w s of t h e N a t i o n ' s E l e c t r i c F u t u r e : A Comparison of Recent S t u d i e s by t h e U.S. Department of Energy and t h e C o n g r e s s i o n a l Research S e r v i c e , DOE/PE-0047, U.S. Department of Energy, Washington, D.C., February 1984.

"35th Annual E l e c t r i c U t i l i t y I n d u s t r y F o r e c a s t , Economic Recovery D r i v e s kWh S a l e s Up," E l e c t r i c a l World, 49-56 (September 1984).

G. Samuels, The Outlook f o r E l e c t r i c i t y Supply and Demand, ORNL/TM9469, Oak Ridge N a t i o n a l L a b o r a t o r y , Oak Ridge, Tennessee, A p r i l 1985.

M. Crawford, "The E l e c t r i c i t y 248-250 ( J u l y 1 9 , 1985).

Nuclear Power i n Assessment, 1984.

A. M. Weinberg e t a l . , The Second Nuclear Era, ORAU/IEA-84-6(M), I n s t i t u t e f o r Energy A n a l y s i s , Oak Ridge A s s o c i a t e d U n i v e r s i t i e s , Oak Ridge, Tennessee, March 1984.

R. K. Lester e t a l . , Nuclear Power P l a n t Design I n n o v a t i o n f o r t h e 1990s: A P r e l i m i n a r y Assessment, MIT-NE-258, M a s s a c h u s e t t s I n s t i t u t e of Technology, Cambridge, M a s s a c h u s e t t s , September 1983.

10.

D. B. Trauger ( e d . ) e t a l . , Nuclear Power Options V i a b i l i t y Study Volume I, Executive Summary, ORNL/TM-9780/1, Oak Ridge N a t i o n a l L a b o r a t o r y , Oak Ridge, Tennessee, September 1986.

11.

D. B. Trauger (ed.) e t a l . , Nuclear Power Options V i a b i l i t y Study Volume 111, Nuclear D i s c i p l i n e T o p i c s , ORNL/TM-9780/3, Oak Ridge N a t i o n a l L a b o r a t o r y , Oak Ridge, Tennessee, September 1986.

12.

D. B. Trauger ( e d . ) e t a l . , Nuclear Power Options V i a b i l i t y Study Volume IV, Bibliography, ORNL/TM-9780/4, Oak Ridge N a t i o n a l L a b o r a t o r y , Oak Ridge, Tennessee, September 1986.

Age

Industry's

Dilemma,"

Uncertainty,

Office

S c i e n c e 229,

Technology

2.1

GROUND RULES AND C R I T E R I A

GROUND RULES AND T H E I R SIGNIFICANCE

To f a c i l i t a t e u s e f u l s t u d y , NPOVS c o n c e n t r a t e d on a c a r e f u l l y sel e c t e d , l i m i t e d group of c o n c e p t s by d e v e l o p i n g and a p p l y i n g ground rules. The f o l l o w i n g t h r e e ground r u l e s were s e l e c t e d : 1.

The n u c l e a r p l a n t d e s i g n o p t i o n should be developed s u f f i c i e n t l y t h a t an o r d e r could be p l a c e d i n t h e 2000-2010 t i m e p e r i o d .

The d e s i g n o p t i o n should be economically c o m p e t i t i v e with e n v i r o n mentally acceptable coal-fired plants.

The d e s i g n o p t i o n should p o s s e s s a high d e g r e e of p a s s i v e s a f e t y t o p r o t e c t t h e p u b l i c h e a l t h and p r o p e r t y and t h e owner's investment.

It i s asGround Rule 1 d e t e r m i n e s t h e t i m e p e r i o d of i n t e r e s t . sumed t h a t , i f o r d e r s of a d d i t i o n a l n u c l e a r power are p l a c e d b e f o r e t h e y e a r 2000, t h e y w i l l be f i l l e d by c u r r e n t o r s l i g h t l y modified d e s i g n s , p r i m a r i l y of LWKs. By t h e t u r n of t h e millenium, t h e a n t i c i p a t e d demand f o r power may p e r m i t c o n s i d e r a t i o n of advanced r e a c t o r c o n c e p t s and t h e i r a s s o c i a t e d advantages. For t h e p r e s e n t t h e concept must be supp o r t e d by an a c t i v e and c a p a b l e i n d u s t r i a l proponent w i t h a c u r r e n t program. It i s c o n s i d e r e d v e r y d i f f i c u l t , perhaps even i m p o s s i b l e , f o r a proponent t o o b t a i n f u n d s , complete a d e s i g n , conduct R&D, b u i l d a d e m o n s t r a t i o n p l a n t o r i t s e q u i v a l e n t , and d e m o n s t r a t e s a t i s f a c t o r y o p e r a t i o n by 2010, u n l e s s d e s i g n work is a l r e a d y underway. The concept must have no major f e a s i b i l i t y problems o r major q u e s t i o n s t h a t must be r e s o l v e d by long-term, h i g h - r i s k R&D p r i o r t o commercial a c c e p t a n c e .

The v a l i d i t y of t h i s ground r u l e w i t h r e s p e c t t o t h e need f o r new e l e c t r i c i t y g e n e r a t i n g c a p a c i t y i n t h e time p e r i o d 2000 through 2010 w a s c o n s i d e r e d e a r l y i n t h e study. S e v e r a l r e f e r e n ~ e s l ' ~were reviewed and o p i n i o n s w e r e s o l i c i t e d from t h e government o f f i c e s , i n d u s t r i e s , u t i l i t i e s , and u n i v e r s i t i e s t h a t were c o n s u l t e d i n t h e conduct of t h e study. Although p r o j e c t i o n s ranged w i d e l y , we concluded t h a t need f o r i n c r e a s e d baseload c a p a c i t y was s u f f i c i e n t l y probable t o j u s t i f y t h e chosen t i m e period. More r e c e n t l y , a comprehensive s t u d y of t h e o u t l o o k f o r e l e c t r i c i t y s u p p l y and demand w a s made a t ORNL which f u r t h e r conf i r m s t h e c h o i c e . 5 The summary of t h a t r e p o r t by G. Samuels i s i n c l u d e d as Appendix B. Ground Rule 2 s t a t e s t h e obvious: For a concept t o be v i a b l e , i t must be economical. The measure chosen i s t h e most l i k e l y and p e r h a p s t h e only major a l t e r n a t i v e , t h e c o a l - f i r e d power p l a n t . Since the cost of c o a l and i t s t r a n s p o r t a t i o n vary widely w i t h l o c a t i o n , t h i s ground r u l e is somewhat s i t e dependent. The most f a v o r a b l e s i t u a t i o n s f o r c o a l might e l i m i n a t e some o r a l l of t h e n u c l e a r c o n c e p t s . However, o t h e r problems such as mining, a c i d r a i n , and carbon d i o x i d e b u i l d u p could become dominant by t h e time p e r i o d c o n s i d e r e d i n t h i s s t u d y .

2-1

2-2 Although l i c e n s a b l e p l a n t s are c o n s i d e r e d adeGround Rule 3: q u a t e l y s a f e by NRC and t h e n u c l e a r i n d u s t r y , p a s s i v e s a f e t y p r o v i d e s a d d i t i o n a l p r o t e c t i o n t h a t i s i n d e p e n d e n t from e n g i n e e r e d d e v i c e s and from human i n t e r v e n t i o n o r management. The added p r o t e c t i o n of t h e owner's i n v e s t m e n t through p a s s i v e l y s a f e d e s i g n s may enhance t h e a c c e p t a b i l i t y of advanced c o n c e p t s as v i a b l e power o p t i o n s . Passive s a f e t y s h o u l d h e l p overcome i n t e r v e n o r ' s o b j e c t i o n s , p u b l i c apprehens i o n , and u t i l i t y h e s i t a t i o n . These f e a t u r e s a l s o may s i m p l i f y p l a n t o p e r a t i o n f o r t h e owner-operator. Thus, p a s s i v e s a f e t y , enhanced beyond t h a t of t h e p r e s e n t s a f e t y p h i l o s o p h y of p r i m a r i l y d i v e r s e and r e d u n d a n t engineered (active) s y s t e m s , may p r o v i d e a n i n g r e d i e n t t o help r e v i t a l i z e the nuclear industry.

2.2

CRITERIA

An e a r l y e f f o r t of t h e s t u d y was t o d e v e l o p c r i t e r i a t h a t r e a c t o r I n t h e reacd e s i g n s would have t o meet t o become v i a b l e i n t h e f u t u r e . t o r a s s e s s m e n t s , t h e seven c r i t e r i a t h a t were developed were used a s a g u i d e t o assess n u c l e a r c o n c e p t s . I n most c a s e s , l a c k of a d e q u a t e and d e t a i l e d d a t a n e c e s s i t a t e d t h e u s e of e n g i n e e r i n g judgment t o d e t e r m i n e compliance w i t h c r i t e r i a . Often t h e judgment had t o be supplemented by t h e f o r m u l a t i o n of f u r t h e r R&D needs t o f a c i l i t a t e more r e l i a b l e conclusions. These needs a r e i d e n t i f i e d f o r e a c h of t h e c o n c e p t s . The c r i t e r i a are augmented by a l i s t of c h a r a c t e r i s t i c s t h a t prov i d e f u r t h e r guidance f o r p r o p e r t i e s judged t o be of importance t o n u c l e a r power v i a b i l i t y . The c h a r a c t e r i s t i c s chosen are n o t r e a d i l y q u a n t i f i a b l e but i n c l u d e f e a t u r e s t h a t complement and a m p l i f y t h e c r i teria.

2.2.1

L i s t i n g of C r i t e r i a , E s s e n t i a l and R e l a t e d D e s i r a b l e C h a r a c t e r i s t i c s , and D i s c u s s i o n of T h e i r A p p l i c a t i o n s The c r i t e r i a a r e l i s t e d below.

Comments f o l l o w e a c h c r i t e r i o n .

The c a l c u l a t e d r i s k t o t h e p u b l i c due t o a c c i d e n t s i s less t h a n o r e q u a l t o t h e c a l c u l a t e d r i s k a s s o c i a t e d w i t h t h e b e s t modern LWRs. T h i s i s a fundamental p u b l i c s a f e t y c r i t e r i o n . To implement i t s t r i c t l y , a p r o b a b i l i s t i c r i s k a s s e s s m e n t (PRA) would be n e c e s s a r y This i s a f o r each new concept and f o r t h e " b e s t modern LWRs." d e s i r e d s i t u a t i o n ; however, where PRAs are u n a v a i l a b l e o r inadeq u a t e , o t h e r a p p r o a c h e s based on judgment must be used. Compliance with t h i s c r i t e r i o n is e s s e n t i a l l y a prerequisite f o r licensing. The c r i t e r i o n i n d i c a t e s t h e f u t u r e importance of PRA.

â&#x20AC;&#x2DC;

2-3 2.

The p r o b a b i l i t x of e v e n t s l e a d i n g t o l o s s of i n v e s t m e n t i s l e s s t h a n 4 o r e q u a l t o 10 per year. P r o t e c t i o n of t h e p l a n t and i t s components and hence t h e investment of t h e u t i l i t y i s t h e f o c u s of t h i s c r i t e r i o n . PRA methods must be a p p l i e d a g a i n as f o r C r i t e r i o n 1 , t o which t h i s c r i t e r i o n i s closely related. The emphasis i s on t h e i n t e g r i t y of t h e e n t i r e p l a c t , s t a r t i n g w i t h t h e r e a c t o r core. The s t a t e d p r o b a b i l i t y of 10 per y e a r f o r loss-of-investment e v e n t s i s n u m e r i c a l l y cons i s t e n t w i t h i n s u r a n c e practices. P u b l i c r e a c t i o n t o n u c l e a r accid e n t s may make a lower p r o b a b i l i t y d e s i r a b l e , r e c o g n i z i n g t h e consumer n a t u r e of t h e u t i l i t y i n d u s t r y sales. Although a p r o b a b i l i t y of loe5 been c i t e d as a p p r o p r i a t e by o t h e r a u t h o r s , l we b e l i e v e t h a t 10i s a c o n s e r v a t i v e f i g u r e f o r l o s s of p l a n t i n v e s t m e n t A unique s i t u a t i o n might a r i s e i f c o n s i d e r a t i o n were g i v e n alone. t o t h e p o s s i b i l i t y t h a t a class of r e a c t o r s could be s h u t down i n r e s p o n s e t o a s i n g l e f a i l u r e of one of t h e r e a c t o r s i n t h a t class. For t h e c o n c e p t a s s e s s m e n t s , i t was assumed t h a t e a c h p l a n t s t a n d s a l o n e and i s i n d e p e n d e n t of a l l o t h e r s . Thus, f a i l u r e p r o b a b i l i t i e s a r e not m u l t i p l i e d by t h e number of u n i t s i n a class.

The economic performance of t h e n u c l e a r p l a n t i s a t l e a s t e q u i v a l e n t t o t h a t f o r coal-fired plants. (Financial goals for the u t i l i t y a r e met, and busbar c o s t s are a c c e p t a b l e t o p u b l i c u t i l i t y commissions.) T h i s c r i t e r i o n s t a t e s t h e b a s i c economic r e q u i r e m e n t s f o r a c c e p t a n c e of a power p l a n t by a u t i l i t y and a p u b l i c u t i l i t y comIt assumes t h a t t h e a v a i l a b l e a l t e r n a t i v e s a r e p r i m a r i l y mission. c o a l - f i r e d o r n u c l e a r power p l a n t s . The e v a l u a t i o n i s based on d a t a provided by t h e proponent, checked f o r c o n s i s t e n c y , t r a n s f o r m e d t o a common b a s i s , and compared w i t h d a t a f o r c o a l - f i r e d power p l a n t s . P u r p o s e l y t h i s i s not a r i g i d c r i t e r i o n . It i s r e c o g n i z e d t h a t c o a l - f i r e d p l a n t c o s t s v a r y w i t h l o c a t i o n , t y p e and q u a l i t y of c o a l , and s t a t e and l o c a l r e g u l a t i o n s . Thus t h e c o m p e t i t i v e p o s i t i o n of a n u c l e a r plant would depend o n l o c a t i o n as w e l l as its own costs and performance, but a n a l y s i s a t t h i s l e v e l of d e t a i l i s beyond t h e s c o p e of t h i s r e p o r t . T h i s c r i t e r i o n a l s o suggests t h e need f o r b e t t e r u n d e r s t a n d i n g of c o s t e s t i m a t i n g , p a r t i c u l a r l y c o s t s a v i n g s a s s o c i a t e d w i t h r e p l i c a s , shop f a b r i c a t i o n , economy of scale, and break-in of new t e c h n o l o g i e s .

The d e s i g n of e a c h p l a n t i s complete enough f o r a n a l y s i s t o show t h a t t h e p r o b a b i l i t y of s i g n i f i c a n t c o s t / s c h e d u l e o v e r r u n s i s a c c e p t a b l y low. T h i s c r i t e r i o n a l s o a d d r e s s e s t h e economic r i s k t o t h e c a p i t a l i n v e s t m e n t as a f f e c t e d by u n a n t i c i p a t e d r e q u i r e m e n t s and s c h e d u l e d e l a y s d u r i n g t h e c o n s t r u c t i o n p e r i o d up t o t h e s t a r t of revenueproducing o p e r a t i o n . S u f f i c i e n t l y complete and d e t a i l e d d e s i g n s , s c h e d u l e s , and s p e c i f i c a t i o n s must e x i s t t o p e r m i t o r d e r l y p l a n n i n g and t o p r e v e n t o r minimize u n a n t i c i p a t e d e v e n t s t h a t l e a d t o c o s t o r

2-4

schedule overruns. An a p p r o p r i a t e review would i n c l u d e t h e comp l e x i t y of d e s i g n , r e q u i r e m e n t s f o r a c c u r a c y and t i g h t t o l e r a n c e s , compactness of a r r a n g e m e n t s , room f o r e x p a n s i o n , and s t r i c t n e s s of sequencing r e q u i r e m e n t s . Review by NPOVS i s l i m i t e d s i n c e d e s i g n s of t h e c o n c e p t s c o n s i d e r e d are n o t complete enough f o r thorough analysis

O f f i c i a l a p p r o v a l of t h e p l a n t d e s i g n must be g i v e n by t h e NRC t o a s s u r e t h e i n v e s t o r and t h e p u b l i c of a h i g h p r o b a b i l i t y t h a t t h e p l a n t w i l l be l i c e n s e d on a t i m e l y b a s i s , i f c o n s t r u c t e d i n accordance w i t h t h e approved d e s i g n . T h i s c r i t e r i o n a d d r e s s e s c o n c e r n f o r d e l a y s and a s s o c i a t e d r i s k f o r f u l l y d e s i g n e d o r r e p l i c a p l a n t s and i s c l o s e l y r e l a t e d t o C r i t e r i o n 4. C r i t e r i o n 6 a l s o a d d r e s s e s t h e c o n c e r n s of t h e adequacy and s u f f i c i e n c y of t h e f i r s t p l a n t . Although c u r r e n t r e g u l a t i o n s p r o v i d e a mechanism f o r t h e p r e a p p r o v a l of s t a n d a r d i z e d p l a n t d e s i g n s (10 CFR 50, Appendices M, N, and 0; and 10 CFR 170.21) and e a r l y s i t e - s u i t a b i l i t y reviews (10 CFR 50, Appendix Q ) , t h e r e i s l i t t l e e x p e r i e n c e i n a p p l y i n g t h i s mechaltism. Also, p a s t e x p e r i e n c e shows t h a t t h e e x i s t e n c e of a completed and l i c e n s e d p l a n t d o e s n o t g u a r a n t e e t h a t a r e p l i c a will e n c o u n t e r no o b s t a c l e s i n o b t a i n i n g a license. T h i s c r i t e r i o n ' s prime c o n c e r n i s w i t h t h e l i c e n s i n g process, i n c l u d i n g p o t e n t i a l f u r t h e r changes i n r e q u i r e m e n t s and regulations. E x p e r i e n c e w i t h l i c e n s i n g i s e x t e n s i v e and s h o u l d be s u f f i c i e n t t o p e r m i t t h e i n d u c t i o n of one-step l i c e n s i n g a t t h e complet i o n of d e s i g n . V e r i f i c a t i o n of q u a l i t y c o n t r o l d u r i n g c o n s t r u c This c r i t e r i o n i s a l s o t i o n , of c o u r s e , would be r e q u i r e d . a d d r e s s e d i n t h e c h a p t e r on r e g u l a t i o n i n Volume 111.

For a new concept t o become a t t r a c t i v e i n t h e m a r k e t p l a c e , demons t r a t i o n of i t s r e a d i n e s s t o be d e s i g n e d , b u i l t , l i c e n s e d , and begin o p e r a t i o n on time and a t p r o j e c t e d c o s t i s n e c e s s a r y . (The demons t r a t i o n may be accomplished by a r e a c t o r d e d i c a t e d t o t h a t purpose p l a n t o r t h e e q u i v a l e n t i n o t h e r expero r by a f i r s t - o f - a - k i n d ience. For t h e l a t t e r , it i s n e c e s s a r y t h a t a l l i m p o r t a n t f e a t u r e s have been demonstrated and t h a t t h e sum of such f e a t u r e s does n o t c o n s t i t u t e a major d e p a r t u r e from e x i s t i n g l i c e n s i n g e x p e r i e n c e . ) For a concept t o be s e r i o u s l y c o n s i d e r e d as a v i a b l e o p t i o n i n t h e power i n d u s t r y , c o n v i n c i n g e v i d e n c e must be p r o v i d e d r e l a t i v e t o major economic and performance claims. A d e m o n s t r a t i o n p l a n t o f f e r s a n e f f e c t i v e way t o acquire t h i s competence. Presumably t h e demons t r a t i o n p l a n t could be used f o r e x t e n s i v e v a l i d a t i o n of computer codes r e l a t e d t o s a f e t y and o p e r a b i l i t y . It might d i r e c t l y demons t r a t e s e l e c t e d s a f e t y f e a t u r e s t o t h e r e g u l a t o r s , t h e i n d u s t r y , and t h e public. The c o n s t r u c t i o n and s t a r t - u p of t h e d e m o n s t r a t i o n p l a n t would p r o v i d e a base of e x p e r i e n c e from which f u t u r e s t a n d a r d i z e d p l a n t s c o u l d be designed. It i s p o s s i b l e t h a t f o l l o w i n g t h e test phase, t h e d e m o n s t r a t i o n p l a n t could be o p e r a t e d f o r an exunit. Where e x t e n s i v e r e l a t e d t e n d e d l i f e as a f i r s t - o f - a - k i n d

2-5

p r i o r experience is available, the p r o b a b i l i t y f o r demonstration i n a first-of-a-kind p l a n t may be high.

The d e s i g n should i n c l u d e only t h o s e n u c l e a r t e c h n o l o g i e s f o r which t h e p r o s p e c t i v e o w n e r / o p e r a t o r has demonstrated competence o r can a c q u i r e competent managers and o p e r a t o r s . For t h e o p e r a t i o n of a new o r s u b s t a n t i a l l y d i f f e r e n t concept t o be s a t i s f a c t o r y , u t i l i t y p l a n t managers and o p e r a t o r s must have a c q u i r e d an adequate background and e x p e r i e n c e w i t h t h e technology and equipment. This c r i t e r i o n r e l a t e s c l o s e l y t o C r i t e r i o n 6 s i n c e t h e d e m o n s t r a t i o n p l a n t can p r o v i d e an e x c e p t i o n a l l y good t r a i n i n g facility. S i m u l a t o r t r a i n i n g h a s proven e f f e c t i v e f o r c u r r e n t power p l a n t s , and s i m u l a t o r s would be n e c e s s a r y t o o l s f o r new concepts. Where t h e concept d e r i v e s from a p r i o r s y s t e m such a s t h e small BWR, t h i s c r i t e r i o n should be r e l a t i v e l y e a s y t o m e e t .

The seven c r i t e r i a have been s e l e c t e d as a primary b a s i s f o r evalua t i n g new o r e x i s t i n g r e a c t o r concepts. These c r i t e r i a o b v i o u s l y are n o t independent s i n c e c r i t e r i a 1 and 2 d e a l w i t h t h e p r o b a b i l i t i e s f o r s u c c e s s f u l o p e r a t i o n o r f a i l u r e , c r i t e r i a 3 t o 6 are p r i m a r i l y economic, However, we deem e a c h t o have and c r i t e r i o n 7 relates t o o p e r a t i o n . s u f f i c i e n t s t a n d - a l o n e merits t o j u s t i f y s e p a r a t e c o n s i d e r a t i o n . The f o u r e s s e n t i a l c h a r a c t e r i s t i c s l i s t e d below i n l a r g e measure a m p l i f y t h e criteria. The d e s i r a b l e c h a r a c t e r i s t i c s which f o l l o w are more peri p h e r a l and, i n some i n s t a n c e s , a r e n o t a p p l i c a b l e t o a l l c o n c e p t s ; howe v e r , t h e y p r o v i d e a u s e f u l c h e c k l i s t f o r e v a l u a t i o n purposes. The e s s e n t i a l c h a r a c t e r i s t i c s f o r f u t u r e n u c l e a r p l a n t s a r e as f o l lows : 0

A c c e p t a b l e f r o n t - e n d c o s t s and r i s k s

C o n s t r u c t i o n economics

Low and c o n t r o l l a b l e c a p i t a l c o s t s ( u t i l i z i n g , f o r example, shop f a b r i c a t i o n , a minimum of n u c l e a r g r a d e components, and standardization) Designed f o r l o n g l i f e t i m e

Investment economics i n c l u d i n g r i s k 0 0 0

Low c o s t s a s s o c i a t e d w i t h a c c i d e n t s Low c o s t s a s s o c i a t e d w i t h c o n s t r u c t i o n d e l a y s Low c o s t s a s s o c i a t e d w i t h d e l a y e d o r u n a n t i c i p a t e d a c t i o n s by r e g u l a t o r y bodies Low c o s t s a s s o c i a t e d w i t h d e l a y e d o r u n a n t i c i p a t e d a c t i o n s f o r environmental p r o t e c t i o n Unit s i z e s t o match l o a d growth U n c e r t a i n t i e s i n technology and e x p e r i e n c e n o t l i k e l y t o n e g a t e i n v e s t m e n t economics

2-6 e

Minimum cost for reliable and safe operation

High availability Minimum requirements for operating and security staffs Designed for ease of access to facilitate maintenance Simple and effective modern control system Low fuel cycle cost Adequate seismic design

Practical ability to construct

Availability of financing Availability of qualified vendors Availability of needed technology Adequately developed licensing regulations applicable to the concept Ease of construction enhanced by design

Public acceptance

Operational safety of power plants Safe transportation and disposal of nuclear waste and radioactive effluent Low effect on rates from construction and operation Adequate management controls on construction and operation Utility and regulatory credibility

Related desirable characteristics are as follows:

1. 2. 3. 4. 5. 6. 7. 8.

9. 10. 11. 12. 13. 14. 15.

practical research, development, and demonstration requirements, ease of siting, load-fo l lowing capability , resistance to sabotage, ease of waste handling and disposal, good fuel utilization, ease of fuel recycle, technology applicable to breeder reactors, high thermal efficiency , low radiation exposure to workers, high versatility relative to applications, resistance to nuclear fuel diversion and proliferation, on-line refueling, ease of decommissioning, and low visual profile.

Several of these characteristics are not readily determined quantitatively and therefore are applied primarily by judgment. They indicate areas and issues of interest and importance. As a rule, an individual characteristic should not determine the fate or viability of a concept.

' . 2-7

2.3

REFERENCES FOR CHAPTER 2

R. K. Lester e t a l . , Nuclear Power P l a n t I n n o v a t i o n f o r t h e 1990s: A P r e l i m i n a r y Assessment, MIT-NE-258, M a s s a c h u s e t t s I n s t i t u t e of Technology, Cambridge, M a s s a c h u s e t t s , September 1983.

U.S. Department of Energy, O f f i c e of P o l i c y , P l a n n i n g and A n a l y s i s , The F u t u r e of E l e c t r i c Power i n America: Economic Supply- f o r Economic Growth, DOE/PE-0045, June 1983.

C o n g r e s s i o n a l Research S e r v i c e , A P e r s p e c t i v e on E l e c t r i c U t i l i t y C a p a c i t y P l a n n i n g , C o m m i t t e e P r i n t 98-M, U. S. Government P r i n t i n g O f f i c e , 1983.

" 3 5 t h Annual Electric U t i l i t y I n d u s t r y F o r e c a s t ," E l e c t r i c a l World (September 1984), pp. 49-56.

G. Samuels, The Outlook f o r E l e c t r i c i t y Supply and Demand, ORNL/TM9469, Oak Ridge N a t i o n a l L a b o r a t o r y , Oak Ridge, Tennessee, A p r i l 1985.

CONCEPT EVALUATIONS

The NPOVS c o n s i d e r e d many c o n c e p t s and s e l e c t e d f o r a s s e s s m e n t t h o s e t h a t were judged t o f i t w i t h i n t h e scope of t h e study. The s e l e c t e d c o n c e p t s are l i s t e d below. E x c l u s i o n does n o t n e c e s s a r i l y i n d i c a t e t h a t t h e concept can not be u t i l i z e d e f f e c t i v e l y w i t h i n o r b e f o r e t h e t i m e frame. The b a s i s f o r e x c l u s i o n has been e i t h e r by t h e Ground Rules o r because as f o r t h e ABWR and APWR, t h e system i s s u f f i c i e n t l y f a r a l o n g i n commercial development t h a t r e v i e w h e r e w a s deemed unnecessary. Concepts c o n s i d e r e d but n o t chosen f o r f u r t h e r e v a l u a t i o n are l i s t e d and d i s c u s s e d i n Appendix C.

3.1

CONCEPT SELECTION AND CLASSIFICATION

A l l t h e c o n c e p t s s e l e c t e d are c o n s i d e r e d advanced, a r e p r e s e n t l y i n development and have v a r i o u s d e g r e e s of i n n o v a t i o n as compared t o c u r r e n t concepts. For convenience, t h e s e l e c t e d c o n c e p t s were class i f i e d i n t h e t r a d i t i o n a l way by t h e i r c o o l a n t and r e s p e c t i v e g e n e r i c name

The c o n c e p t s s e l e c t e d a r e :

L i g h t Water R e a c t o r s (LWR) a.

PIUS - P r o c e s s ASEA-ATOM

Small BWR Electric

Inherent

- Boiling

Ultimate

Water

Reactor

- promoted

Safety

- promoted

General

L i q u i d Metal R e a c t o r s (LMR) c. PRISM

Power

General

Reactor I n t r i n s i c a l l y Safe Module the E l e c t r i c advanced concept s u p p o r t e d by

DOE

SAFR

e. LSPB

Sodium Advanced F a s t R e a c t o r t h e Rockwell I n t e r n a t i o n a l advanced concept s u p p o r t e d by DOE

- the

Large-Scale P r o t o t y p e Breeder concept s u p p o r t e d by DOE and EPRI

EPRI-CoMO

High Temperature R e a c t o r s (HTR)

Side-by-Side Modular The c o r e and steam g e n e r a t o r i n s e p a r a t e steel v e s s e l s i n a side-by-side c o n f i g u r a t i o n . The concept i s s u p p o r t e d by DOE and promoted by GCRA and ind u s t r i a l firms.

3-1

3 -2

A l l t h e c o n c e p t s s e l e c t e d are judged t o f i t w i t h i n t h e scope of t h e study. They are a l l p o t e n t i a l l y a v a i l a b l e i n t h e time p e r i o d 2000-2010. All a r e e s t i m a t e d by t h e i r promoters t o be economically c o m p e t i t i v e w i t h c o a l - f u e l e d power p l a n t s , and a t t e n t i o n has been g i v e n t o d e s i g n i n g them t o i n c l u d e f e a t u r e s of p a s s i v e s a f e t y .

3.2

CONCEPT EVALUATION METHODS AND LIMITATIONS

The assessment of t h e c o n c e p t s s e l e c t e d was performed u s i n g t h e c r i t e r i a as a guide. F i r s t , a v a i l a b l e i n f o r m a t i o n has been g a t h e r e d and i s summarized i n t h i s r e p o r t . C l a i m s , a d v a n t a g e s , and d i s a d v a n t a g e s were t h e n f o r m u l a t e d f o r each concept. I n many cases, t h e a v a i l a b l e Need f o r i n f o r m a t i o n i s n o t s u f f i c i e n t t o r e a c h a f i n a l conclusion. f u r t h e r i n f o r m a t i o n i s t h e n f o r m u l a t e d i n t h e form of R&D r e q u i r e m e n t s i nc l u d i n g design. A n o p p o r t u n i t y was g i v e n t o t h e concept p r o p o n e n t s t o comment on t h e material r e l a t e d t o t h e i r concept. These comments were c o n s i d e r e d c a r e f u l l y , but not a l l were a c c e p t e d o r i n c l u d e d i n t h e t e x t . The proponents’ a s s i s t a n c e has been h i g h l y v a l u a b l e and i s a p p r e c i a t e d .

The d e s c r i p t i o n s and e v a l u a t i o n s a r e p r i m a r i l y based on i n f o r m a t i o n a v a i l a b l e i n September 1985. S i n c e a l l of t h e c o n c e p t s have c o n t i n u e d i n development, d e s i g n changes may a f f e c t t h e i n f o r m a t i o n p r e s e n t e d here. Although t h e o b s e r v a t i o n s of t h e r e p o r t are c o n s i d e r e d v a l i d a t t h e t i m e of w r i t i n g , t h e r e a d e r s h o u l d use care i n d e t e r m i n i n g subsequent d e s i g n changes and i n assessing t h e i r i m p a c t b e f o r e drawing seri o u s conclusions.

3.3

LIGHT WATER REACTORS ( LWRs)

The next two s e c t i o n s d i s c u s s t h e l i g h t water r e a c t o r (LWR) conc e p t s i n v e s t i g a t e d by NPOVS. The P r o c e s s I n h e r e n t Ultimate S a f e t y (PIUS) and Small (Advanced) B o i l i n g Water R e a c t o r (BWR) c o n c e p t s a r e i n p r e l i m i n a r y s t a g e s of development. Both c o n c e p t s b u i l d on LWR e x p e r i ence.

3.3.1 3.3.1.1

PIUS Description

The P r o c e s s I n h e r e n t U l t i m a t e S a f e t y (PIUS) ~ o n c e p t l ’ ~i s b a s i c a l l y a FWR-type NSSS w i t h c o r e r e a c t i v i t y c o n t r o l l e d both by v a r y i n g t h e s o l u b l e boron c o n c e n t r a t i o n i n t h e primary system c o o l a n t c i r c u i t and by t h e n a t u r a l feedback p r o v i d e d by t h e f u e l and moderator negative tempera t u r e c o e f f i c i e n t s of r e a c t i v i t y . The c u r r e n t “modular“ p l a n t design4 c o n s i s t s of t h r e e s e p a r a t e c o r e s l o c a t e d w i t h i n t h r e e s e p a r a t e primary c i r c u i t s which are surrounded by a common pool of h e a v i l y b o r a t e d water

3 -3 m a i n t a i n e d a t low temperature. The pool and t h e t h r e e reactor-steamg e n e r a t o r modules are c o n t a i n e d w i t h i n a p r e s t r e s s e d c o n c r e t e p r e s s u r e v e s s e l (PCPV) and u t i l i z e a common p r e s s u r i z e r . Steam i s r o u t e d from each steam g e n e r a t o r t o a c o n v e n t i o n a l balance of p l a n t c o n s i s t i n g most l i k e l y of a common steam header f e e d i n g one o r p o s s i b l y two t u r b i n e g e n e r a t o r sets. The r e a c t o r s y s t e m i s designed t o p r o v i d e n a t u r a l thermal convect i o n under r e a c t o r shutdown c o n d i t i o n s by p l a c i n g each r e a c t o r c o r e a t t h e base of a h o t water column about 30 meters high. A l a r g e opening i s provided between t h e primary system i n e a c h module and t h e pool water a t b o t h t h e t o p and bottom of t h e c o r e riser column. Honeycomb a r r a y s of t u b e s a r e provided i n t h e s e open r e g i o n s t o i n h i b i t c o n v e c t i o n c u r r e n t s d u r i n g normal o p e r a t i o n of t h e r e a c t o r , w i t h t h e h y d r a u l i c head of t h e f l u i d i n t h e s u r r o u n d i n g pool being balance by t h e pump head i n e a c h primary c i r c u i t . Upon l o s s of f o r c e d c o n v e c t i o n flow i n one of t h e p r i mary c i r c u i t s , t h e d i f f e r e n c e i n d e n s i t y between t h e h o t and c o l d w a t e r r e g i o n s c a u s e s t h e b o r a t e d pool water t o flow i n t o t h e c o r e r e g i o n of t h e a f f e c t e d module. F i g u r e 3 . 1 i l l u s t r a t e s t h e a x i a l c o n f i g u r a t i o n of a s i n g l e r e a c t o r steam-generator module showing t h e flow p a t h s of t h e primary c i r c u i t . The PIUS Mk I1 module, i l l u s t r a t e d i n F i g u r e 3 . 1 , u t i l i z e s a s i n g l e chimney-type riser p i p e t o c a r r y c o o l a n t from t h e c o r e up t o a h o t l e g r e c i r c u l a t i o n pump from which primary c i r c u i t flow proceeds down through a bayonet steam g e n e r a t o r i n a s i n g l e p a s s t o t h e c o r e i n l e t . Density l o c k s a r e provided between t h e primary c i r c u i t and pool water b o t h below t h e c o r e and around t h e p r e s s u r i z e r riser p i p e from t h e primary r e c i r c u l a t i o n loop. F i g u r e 3 . 1 shows t h e c o n n e c t i o n between t h e module and t h e common p r e s s u r i z e r f o r t h e t h r e e modular u n i t s . Figure 3.2 p r o v i d e s two p l a n views of t h e i n t e r n a l s of t h e PCPV showing t h e f u e l s t o r a g e l o c a t i o n s and t h e mobile r e f u e l i n g t u r n t a b l e below t h e r e a c t o r steam-generator modules on t h e r i g h t and t h e upper p i p i n g c o n n e c t i o n s on the l e f t . F i g u r e 3 . 3 i l l u s t r a t e s t h e PCPV w i t h a c e n t r a l c a v i t y and a drawer-like

closure s l a b and pressure s e a l .

The system i s d e s i g n e d f o r a c o n s t a n t water flow r a t e t h r o u g h e a c h primary c i r c u i t and a c o n s t a n t r e a c t o r o u t l e t t e m p e r a t u r e over t h e normal range of power o p e r a t i o n . I n t h e e v e n t of pump s t o p p a g e i n any o r a l l modules, t h e f o r c e d c o n v e c t i o n c o o l a n t flow through t h e primary c i r c u i t pump and steam g e n e r a t o r comes t o a s t o p , but thermal c o n v e c t i o n through t h e c o r e and i n t o t h e pool w i l l i n i t i a t e because of t h e d i f f e r e n t i a l head a v a i l a b l e f o r n a t u r a l thermal convection. This c a u s e s t h e c o o l b o r a t e d pool water t o e n t e r t h e c o r e , quenching t h e n u c l e a r react i o n and c o o l i n g t h e f u e l elements. Shutdown i n i t i a t e d f o r a s i n g l e module should n o t a f f e c t o p e r a t i o n of t h e remaining modules. The volume c a p a c i t y of t h e PCPV should be s u f f i c i e n t t o p r o v i d e c o o l i n g w a t e r f o r about a week t o accommodate decay h e a t i n g from a l l t h r e e r e a c t o r s w i t h o u t a d d i t i o n of water from an e x t e r n a l s o u r c e . The c o n c e n t r a t i o n of boron w i t h i n e a c h c o r e r e g i o n i s c o n t r o l l e d by i n j e c t i n g deborated coolant obtained from one of two s e p a r a t e

3-4 OR N L-DWG 85-13160R

STEAM PIPE

F E EDWATER PIPE

Fig. 3.1. PIUS p l a n t .

V e r t i c a l s e c t i o n t h r o u g h o n e module of a MK I T modular

ORNL-OWG 8613150

/- RECIRCULATION -. .__^ PUMP COOLER

STEAM VALVE INTERIM STORAGE

FUEL RACK

w J

REACTOR MODULE IN OPERATING POSITION

DENSITY LOCK FUNNEL B-B .___

If-L SPENT

Fig.

3.2.

Horizontal

sections

through

a three-module

FUEL RACKS

MK II

PIIJS plant.

3-6

ORNL-DWG 85-13159

Ill::...:

:::

::::

Fig. 3.3. 600 MW(e)

Prestressed concrete vessel for PIUS plants of 500 to

3-7 d i s t i l l a t i o n units. Both d i s t i l l a t i o n u n i t s may be used a f t e r a scram t o r e e s t a b l i s h plant readiness. The s i z e of t h e c o l l e c t i o n t a n k s and of t h e b o r a t e d and c l e a n water t a n k s i s such t h a t two c o n s e c u t i v e scrams can be accommodated w i t h o n l y one e v a p o r a t o r o p e r a t i n g . Each r e a c t o r w i l l o p e r a t e w i t h o u t c o n t r o l r o d s , and t h e boron c o n c e n t r a t i o n c o n t r o l w i l l p r o v i d e t h e n e c e s s a r y r e a c t i v i t y c o n t r o l above t h a t provided by i n h e r e n t r e a c t i v i t y feedback and b u r n a b l e poisons. The PIUS r e a c t o r concept i s proposed a s a very s a f e r e a c t o r u t i F u r t h e r , i t is proposed as a s y s t e m which h a s a l i z i n g LWR technology. c o m p e t i t i v e c a p i t a l c o s t because of i t s s a f e t y and c o n t r o l c h a r a c t e r istics. The p r a c t i c a l i t y of t h e concept rests on t h e s t a b i l i t y and cont r o l of t h e f l u i d i n t e r f a c e s between t h e pool water and each hot primary c i r c u i t , i n c l u d i n g s t a b i l i t y under t r a n s i e n t c o n d i t i o n s . Other import a n t f a c t o r s are t h e p r a c t i c a l i t y of t h e PCPV d e s i g n , of r e f u e l i n g by u s e of a r o t a t i n g t u r n t a b l e w i t h i n a deep pool, of i n s u l a t i o n r e q u i r e ments, of replacement of equipment, t h e non-safety g r a d e b a l a n c e of p l a n t and t h e p r a c t i c a l i t y of o p e r a t i n g t h r e e r e a c t o r s w i t h o u t any c o n t r o l r o d s and w i t h o u t i n t e r f e r e n c e due t o thermal and p r e s s u r e transients. A l l of t h e above areas a r e being e v a l u a t e d . A fundamental d e s i g n goal of PIUS i s t h e p r e s e r v a t i o n of f u e l The approach i s claimed t o i n t e g r i t y under a l l c r e d i b l e c o n d i t i o n s . a c h i e v e complete p r o t e c t i o n a g a i n s t c o r e m e l t i n g o r o v e r h e a t i n g due t o the following: any c r e d i b l e equipment f a i l u r e ,

n a t u r a l e v e n t s such as e a r t h q u a k e s and f l o o d s ,

reasonably c r e d i b l e operator mistakes,

combinations of the above

as w e l l a s

i n s i d e s a b o t a g e by p l a n t p e r s o n n e l ,

t e r r o r i s t attacks i n c o l l a b o r a t i o n w i t h i n s i d e r s ,

m i l i t a r y a t t a c k (e.g., n u c l e a r weapons),

abandonment of t h e p l a n t by o p e r a t i n g personnel.

aircraft

with

'off-the-shelf'

non-

The d e s i g n e r s s t a t e t h a t every a t t e m p t i s made t o a c h i e v e t h e s e g o a l s v i a p a s s i v e means (i.e., w i t h o u t r e l i a n c e on s a f e t y equipment which could f a i l t o f u n c t i o n ) . This p a s s i v e p r o t e c t i o n should l a s t f o r a minimum of one week f o l l o w i n g any i n i t i a t i n g event. Thus PIUS s h o u l d meet w e l l t h e T h i r d Ground Rule. The d e s i g n e r ' s p o s i t i o n i s t h a t a l l of t h e s e g o a l s can be a t t a i n e d v i a f u l f i l l m e n t of two b a s i c s a f e t y functions: 1.

t h e d e s i g n p r e c l u d e s any c r e d i b l e c i r c u m s t a n c e which can r e s u l t i n uncovering of t h e c o r e , and

3 -8 2.

3.3.1.2

t h e d e s i g n p r e v e n t s c o r e h e a t g e n e r a t i o n r a t e s which would exceed t h e c o n v e c t i v e h e a t removal c a p a b i l i t y of t h e submerging water under a l l c o n c e i v a b l e c o n d i t i o n s . C l a i m s , Advantages, and D i s a d v a n t a g e s E v a l u a t e d A g a i n s t C r i t e r i a , E s s e n t i a l and D e s i r a b l e C h a r a c t e r i s t i c s

The p r o p o n e n t s claims and p o t e n t i a l c o n c e p t a d v a n t a g e s a r e d i s c u s s e d b r i e f l y as f o l l o w s f i r s t i n t h e o r d e r of t h e p r e l i m i n a r y c r i t e r i a and t h e n w i t h r e g a r d t o both e s s e n t i a l and d e s i r a b l e c h a r a c t e r i s t i c s :

P u b l i c Risk: PIUS a p p e a r s t o be r e s i s t a n t t o f u e l damage under a l l a n t i c i p a t e d t r a n s i e n t s and f o r l o n g p e r i o d s (-7-10 d a y s ) w i t h o u t human i n t e r v e n t i o n o r a c t i v e e n g i n e e r e d s a f e t y f e a t u r e s a f t e r worst case a c c i d e n t s . ASEA-ATOM claims t h a t normal o p e r a t i n g releases are e x p e c t e d t o be less than f o r c u r r e n t LWRs. The lower power d e n s i t y and e x p e c t e d good c h e m i s t r y behavior should l i m i t t h e o c c u r r e n c e of minor f u e l leaks. ASEA-ATOM a r g u e s t h a t p r e s s u r e c y c l e s i n t h e l a r g e pool where d e p l e t e d f u e l i s s t o r e d w i l l n o t exceed c l a d strength limits s o that pool contamination will be minimal. Steam g e n e r a t o r t u b e l e a k s w i l l be c o n t a i n e d by steam-line i s o l a t i o n v a l v e s and a secondary p r e s s u r e boundary r a t e d a t primary system p r e s s u r e ( 9 MPa o r 1300 p s i a ) up t o t h e i s o l a t i o n v a l v e l o c a t i o n j u s t o u t s i d e t h e w a l l of t h e PCPV. PIUS i s a l s o d e s i g n e d t o be h i g h l y r e s i s t a n t t o e x t e r n a l t h r e a t s such as a i r c r a f t c r a s h e s , t e r r o r i s m , and sabotage.

Investment Risk: S i n c e c o r e damage i s p r e c l u d e d d u r i n g normal t r a n s i e n t s and d e l a y e d f o r a t l e a s t a week w i t h o u t human i n t e r v e n t i o n d u r i n g worst case a c c i d e n t s , t h e p r o b a b i l i t y of l o s s of i n v e s t m e n t a r i s i n g from c o r e melt a p p e a r s t o be much less t h a n 1 0 - 4 / p l a n t y e a r (no PRA y e t t o s u p p o r t t h i s conclusion).

Economic C o m p e t i t i v e n e s s : ASEA-ATOM claims economic competit i v e n e s s w i t h coal-f i r e d p l a n t s under Swedish market condit i o n s and assuming a non-safety g r a d e b a l a n c e of p l a n t (BOP). T h e i r unpublished s t u d i e s show t h a t a PIUS 500 MW(e) nonmodular p l a n t has twice t h e c a p i t a l c o s t of a Swedish 600 MW(e) c o a l - f i r e d p l a n t but an energy c o s t t h a t i s less t h a n t h e c o a l - f i r e d p l a n t by between 15% ( f o r c o a l a t $50 p e r metric t o n ) and 25% ( f o r c o a l a t $60 p e r metric t o n ) , where t h e c o s t of c o a l c o n t r i b u t e s a p p r o x i m a t e l y 60-702 of t h e l e v e l i z e d e n e r g y cost. S i m i l a r l y , r e c e n t ASEA-ATOM estimates r e p o r t e d f o r t h e 600 MW(e) modular p l a n t show t h e same relat i o n t o c o a l - f i r e d c a p i t a l c o s t s and between a 20% and 30% adv a n t a g e i n energy c o s t s f o r t h e c o a l p r i c e s n o t e d above. ASEA-ATOM has not provided s u p p o r t i n g documentation of t h e a n a l y s i s nor i s t h e r e s u f f i c i e n t i n f o r m a t i o n a v a i l a b l e curr e n t l y t o perform an independent a n a l y s i s . However, i f t h e

3-9 PIUS can be b u i l t a t twice t h e c a p i t a l c o s t of a c o a l - f i r e d p l a n t , i t would be c o m p e t i t i v e i n t h e United S t a t e s i n r e g i o n s where Western low-sulfur c o a l i s s e l l i n g a t $35 p e r metric t o n and where E a s t e r n h i g h - s u l f u r c o a l i s s e l l i n g a t $45 p e r metric t o n assuming t h a t t h e p r i c e of c o a l i n t h e f u t u r e escalates a t 1.5% o r more above i n f l a t i o n .

P r o b a b i l i t y of Cost/Schedule Overruns: ASEA-ATOM r e c o g n i z e s t h e need t o develop a complete d e s i g n b e f o r e i n i t i a t i n g cons t r u c t i o n and i s working toward t h a t g o a l .

Licensability: ASEA-ATOM has a d r a f t l i c e n s i n g p l a n , i s a c t i v e l y engaged i n d i a l o g u e w i t h NRC-NRR and h a s p l a n s t o proceed w i t h s e c u r i n g NRC f i n a l d e s i g n a p p r o v a l (FDA) by J a n u a r y 1992.

Demonstration of Readiness: ASEA-ATOM b e l i e v e s t h a t a nonn u c l e a r d e m o n s t r a t i o n p l a n t ( i n c l u d i n g a f u l l - s c a l e steam g e n e r a t o r module) built i n a tank t o d e m o n s t r a t e t h e fundamental t h e r m a l - h y d r a u l i c s a f e t y p r i n c i p l e s of PIUS can t h e p l a n t t o unwarranted d e m o n s t r a t e t h e r e s i s t a n c e of shutdowns from minor t r a n s i e n t s . They f u r t h e r b e l i e v e t h a t s u c h a d e m o n s t r a t i o n w i l l s i m p l i f y l i c e n s i n g and q u e l l t h e arguments of d e t r a c t o r s w i t h r e g a r d t o t h e p o t e n t i a l of h i g h u n a v a i l a b i l i t i e s r e s u l t i n g from minor u p s e t s . ASEA-ATOM a l s o believes that a non-nuclear demonstration p r e s e n t s the p o s s i b i l i t y of going d i r e c t l y t o a f i n a n c i a l l y s e l f s u p p o r t i n g power p l a n t w i t h o u t burdening t h e development program w i t h t h e l a r g e e x p e n d i t u r e and t i m e d e l a y of a n u c l e a r demonstration. ASEA-ATOM b e l i e v e s t h a t t h e f u l l - s c a l e non-nuclear test would r e s o l v e most c o n s t r u c t i b i l i t y problems e x c e p t f o r t h e PCPV; however, t h e y c o n s i d e r t h e c o n s t r u c t a b i l i t y of t h e PCPV t o be based on an e s t a b l i s h e d technology and t o be easier t o cons t r u c t t h a n t h e i r c u r r e n t BWR p r e s s u r e s u p p r e s s i o n containment buildings. Such a d e m o n s t r a t i o n would n o t f u l l y a d d r e s s a l l i s s u e s of c o n s t r u c t a b i l i t y and maintenance, p a r t i c u l a r l y longterm r e q u i r e m e n t s f o r s t e a m g e n e r a t o r c l e a n i n g .

Owner Competence: Any p r e v i o u s o p e r a t o r of an LWR should be a b l e t o b u i l d and o p e r a t e PIUS assuming t h a t t h e p l a n t The o p e r a t i o n a l complicao p e r a t e s as p r o j e c t e d by ASEA-ATOM. t i o n s are p o s s i b l y t h e use of t h r e e r e a c t o r - s t e a m g e n e r a t o r modules t o f e e d a s i n g l e steam h e a d e r , steam g e n e r a t o r t u b e c l e a n i n g , p r e s s u r e c o n t r o l of t h e primary system and r e f u e l t n g t h r e e c o r e s i n a deep pool. ASEA-ATOM claims t h a t t h e s e f e a t u r e s a c t u a l l y s i m p l i f y o p e r a t i o n and t h a t t h e i r a n a l y s e s supp o r t t h i s claim. ASEA-ATOM p o i n t s t o t h e u s e of t h e l a r g e (-200 m3) p r e s s u r i z e r as a b u f f e r d u r i n g t r a n s i e n t e v e n t s . A c t u a l o p e r a t i n g e x p e r i e n c e i s needed t o c o r r o b o r a t e t h e s e claims. Other t e c h n o l o g i e s appear t o be e x t e n s i o n s o r modific a t i o n s t o e x i s t i n g LWR technology.

3-10

Essential Characteristics: PIUS has great promise according to its proponents of achieving safe, reliable and cost competitive operation; however, as noted under the evaluation against criteria, most of these claims require further analytical or experiential substantiation, particularly in the area of construction costs and availability. The sizing of PIUS at about 600 MW(e) appears to meet the need for smaller increments in base load capacity additions consistent with current load growth projections, and modularization of the reactor-steam generator configuration is an attempt to simplify plant construction. Resistance to accidents and external events such as sabotage is inherent in the design as conceptualized by the proponents. Such resistance implies low costs associated with accidents, possibly smaller security staffs and the reliance on passive safety features under worst case scenarios to delay required mitigative actions and perhaps to avoid having to provide for area evacuation.

Desirable Characteristics: Aside from the lack of planning for fuel recycle, the low thermal efficiency, lack of on-line refueling, and the questionable versatility relative to application (except for district heating) because of the low grade of steam compared to other higher temperature concepts, PIUS possesses most of the desirable characteristics listed in Chapter 2. Some areas of potential weakness such as waste handling and disposal, decommissioning and diversion and proliferation are generic problems shared in common with virtually all reactor concepts because the proposed solutions to these type of concerns are often subject to a variety of interpretation by national and international regulatory, governmental and public interest bodies. Replacement of the nuclear steam supply equipment for extended life may be easier for PIUS than for other LWR concepts assuming that the vessel remains qualified. Because of passive safety characteristics, PIUS does appear to be potentially much more flexible to siting requirements and more m c h resistant to sabotage and diversion than current generation LWRs.

The potential disadvantages are discussed as follows: 1.

Public Risk: The potential for refueling accidents must be addressed more fully with attention to the control and monitoring of heavy loads above the spent fuel storage locations within the PCPV. ASEA-ATOM claims that major maintenance such as pump replacement could be performed with the freshly exposed fuel in the operating positions under the steam generators. The possibility of damage to fuel stored from previous operating cycles, claimed to pose little radiological hazard, may need extensive study.

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I n v e s t m e n t Risk:

a. b.

PIUS a v a i l a b i l i t y has n o t been f i r m l y e s t a b l i s h e d by a n a l y s i s and t e s t i n g t o d a t e . Deep pool maintenance may be a problem w i t h t h e onus of l o n g shutdowns. ASEA-ATOM c i t e s t h e i r replacement of BWR i n t e r n a l r e c i r c u l a t i o n pumps as an a d e q u a t e e x p e r i e n c e b a s e f o r deep pool maintenance on d i f f i c u l t c o n f i g u r a t ions.

Economic C o m p e t i t i v e n e s s :

PIUS c o m p e t i t i v e n e s s w i t h c o a l and o t h e r n u c l e a r o p t i o n s h a s n o t been e s t a b l i s h e d i n d e p e n d e n t l y . PIUS c a p i t a l c o s t s have n o t been confirmed f o r U.S. s i t i n g .

On-line r e f u e l i n g i s n o t p o s s i b l e f o r PIUS s o r e f u e l i n g shutdowns m s t be s c h e d u l e d as i n c u r r e n t LWRs. The t h r e e c o r e s must be s h u t down f o r one t o be s e r v i c e d .

PIUS l o a d f o l l o w i n g may have been enhanced by a t h r e e r e a c t o r system, but o p e r a t i o n of one o r more modules a t reduced power may be d i f f i c u l t depending upon t h e d i f f i c u l t i e s e n c o u n t e r e d i n c o n t r o l l i n g steam g e n e r a t o r f e e d water i n j e c t i o n r a t e t o match c o r e power l e v e l s . The e f f e c t s of f u e l c y c l e c o s t p e n a l t i e s have n o t been adeq u a t e l y a d d r e s s e d f o r t h e case i n which t h e t h r e e c o r e s ASEA-ATOM s t a t e s t h a t become o u t of phase i n burnup. less f u e l w i l l be added i n r e f u e l i n g t h e a f f e c t e d module; t h i s s o l u t i o n t o g e t back i n phase i n c u r s a f i n a n c i a l p e n a l t y which i s acknowledged b u t n o t f u l l y a d d r e s s e d . Another a l t e r n a t i v e i s t o i n t e r c h a n g e f u e l s between modules.

PIUS i s n o t amenable t o e f f i c i e n t f u e l r e c y c l e because of t h e emphasis on o n s i t e 30-year s t o r a g e of s p e n t f u e l .

PIUS h a s a r e l a t i v e l y low t h e r m a l e f f i c i e n c y .

P r o b a b i l i t y of C o s t / S c h e d u l e Overruns: N o s p e c i f i c disadvantage i d e n t i f i e d p r o v i d e d component and system t e s t i n g have been completed s u c c e s s f u l l y p r i o r t o d e s i g n completion.

Licensability:

As w i t h a l l advanced r e a c t o r s , PIUS h a s n o t y e t been f o r c e d t o a d d r e s s post-TMI l i c e n s i n g p r o c e e d i n g s . The p o s s i b i l i t y e x i s t s f o r t h e need t o a d d r e s s t h e p r o b a b i l i s t i c r i s k of t h e consequences of beyond d e s i g n b a s i s a c c i d e n t s coupled t o t h e c o s t - b e n e f i t of a d d i n g equipment t o a v e r t t h e r i s k a s s o c i a t e d from v e r y low p r o b a b i l i t y accidents. The r e g u l a t o r y a u t h o r i t i e s may r e q u i r e t h e

3-12 u s e of a s e p a r a t e containment, a d e d i c a t e d 30-day water supply, control rods, a safety-grade c o n t r o l room, d e d i c a t e d emergency e l e c t r i c a l power a n d / o r o t h e r s a f e t y g r a d e systems on t h e b a l a n c e of p l a n t . If so, the e f f e c t w i l l be i n c r e a s e d p l a n t c o s t t o meet such r e q u i r e m e n t s . There a p p e a r s t o be a p o t e n t i a l need f o r some l e v e l of secondary containment d u r i n g shutdown o p e r a t i o n s w i t h t h e v e s s e l seal broken. b.

Requirements f o r area e v a c u a t i o n a r e a l s o n o t f i r m l y e s t a b l i s h e d f o r PIUS. ASEA-ATOM a r g u e s c o n v i n c i n g l y t h a t s i g n i f i c a n t releases could only occur a f t e r an extended t i m e d e l a y (7-10 d a y s ) f o l l o w i n g an a c c i d e n t . Such a d e l a y i n t a k i n g a c t i o n t o add water, assuming a d e q u a t e p r i o r p r o v i s i o n had been made, would imply a c h a o t i c s o c i a l s i t u a t i o n external t o t h e plant. However, t h e PIUS pool could become s e v e r e l y contaminated from unant i c i p a t e d f u e l f a i l u r e s , f o r example, due t o manufacturi n g problems. The r e s u l t would be e i t h e r a long shutdown t o a l l o w decay of r a d i o a c t i v e n u c l i d e s w i t h r e l a t i v e l y slow water cleanup rates o r an a c c e l e r a t e d c l e a n u p r a t e i n which o u t - o f - r e a c t o r i n c i d e n t s would be p o s s i b l e . ASEA-ATOM a r g u e s t h a t e l i m i n a t i n g t h e need f o r immediate e v a c u a t i o n i s b e i n g a d d r e s s e d and t h a t t h e i r water c l e a n up systems should be comparable i n speed and s a f e t y t o c u r r e n t LWRs and t h i s a p p e a r s t o be a c h i e v a b l e .

Demonstration of Readiness: Steam g e n e r a t o r c l e a n i n g r e q u i r e ments may not be confirmed u n t i l a f t e r t h e f i r s t p l a n t h a s been i n o p e r a t i o n f o r some t i m e . ASEA-ATOM a r g u e s t h a t c l e a n i n g r e q u i r e m e n t s can be s t u d i e d i n r e l a t i v e l y small scale (non-nuclear) t e s t s , but such i d e a l i z e d t e s t i n g a l t h o u g h imp o r t a n t may be i n a d e q u a t e t o r e p r e s e n t a c t u a l p l a n t operation. Improvements i n d e s i g n f o r c l e a n i n g have been r e p o r t e d by ASEA-ATOM, but d e t a i l s a r e n o t y e t a v a i l a b l e . Fuel h a n d l i n g , in-pool maintenance, b o r a t i o n c o n t r o l , w e t i n s u l a t i o n , submerged pumps, c o r e c a r r i e r m a n i p u l a t i o n , and t h e PCPV c l o s u r e i n v o l v e new d e s i g n s and technology. Although t h e s e f e a t u r e s can be t e s t e d i n mockup f a c i l i t i e s , t h e y w i l l r e q u i r e a c t u a l d e m o n s t r a t i o n with r e a c t o r o p e r a t i o n . However, s i n c e t h e concept draws h e a v i l y on PWR e x p e r i e n c e , t h e d e m o n s t r a t i o n r e a c t o r may be determined as commercially v i a b l e f o l l o w i n g a s u c c e s s f u l test period.

Owner Competence:

Essential Characteristics: Most of t h e s i g n i f i c a n t p o t e n t i a l disadvantages a s s o c i a t e d with the e s s e n t i a l c h a r a c t e r i s t i c s have been a d d r e s s e d above under t h e c r i t e r i a f o r Investment R i s k , Economic C o m p e t i t i v e n e s s and L i c e n s a b i l i t y . As ment i o n e d under t h e d i s c u s s i o n of a d v a n t a g e s , estimates of c o s t and a v a i l a b i l i t y need t o be s u b s t a n t i a t e d .

No s p e c i f i c d i s a d v a n t a g e i d e n t i f i e d .

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3.3.1.3

D e s i r a b l e C h a r a c t e r i s t i c s : Most of t h o s e n o t m e t by PIUS were l i s t e d above f o r comparison purposes i n t h e e v a l u a t i o n of t h e advantages. Load f o l l o w i n g i s one area which t h e PIUS propon e n t s claim has been s o l v e d by m o d u l a r i z a t i o n b u t t h e c o n t r o l s y s t e m , as noted under t h e economic c o m p e t i t i v e n e s s , may be more complicated and h a r d e r t o o p e r a t e e f f e c t i v e l y t h a n curr e n t l y e n v i s i o n e d by t h e proponents. However, e x p e r i e n c e w i t h c o n t r o l i n e x p e r i m e n t a l f a c i l i t i e s i s r e p o r t e d t o be f a v o r able. With r e s p e c t t o r a d i a t i o n exposure t o workers, c o r r o s i o n product a c t i v a t i o n and t r a n s p o r t i s an u n r e s o l v e d c o n s i d e r a t i o n s i n c e t h e b e h a v i o r may be d i f f e r e n t from t h a t of t h e s t a n d a r d PWR. R&D Needs and open Q u e s t i o n s E v a l u a t e d

Development, t e s t i n g and d e m o n s t r a t i o n of an optimum geometry f o r t h e h o t / c o l d water i n t e r f a c e mechanism t o e n s u r e c o r e shutdown/quench when r e q u i r e d and t o p r e c l u d e unwarranted shutdown i n r e s p o n s e t o minor t r a n s i e n t s and u p s e t s are needed. ASEA-ATOM h a s conducted p r e l i m i n a r y tests which produced f a v o r a b l e r e s u l t s , but more comprehensive t e s t i n g and a n a l y s i s are r e q u i r e d and are planned.

ASEA-ATOM i s a t t e m p t i n g t o d e m o n s t r a t e by a n a l y s i s and t e s t i n g t h a t p l a n t a v a i l a b i l i t y w i l l be s u f f i c i e n t l y h i g h t o a v e r t t h e p o s s i b i l i t y t h a t t h e d e s i g n i s t o o complicated t o o p e r a t e economically. This important e v a l u a t i o n would j u s t i f y independent s t u d y .

S a f e t y r e l i e f v a l v e s , steam s u p p r e s s i o n and f i l t e r i n g s y s t e m s may r e q u i r e e x t e n s i v e t e s t i n g s i n c e t h e y are e s s e n t i a l compon e n t s of t h e decay h e a t removal system.

Components w i t h i n t h e PCPV, t h e u n u s u a l l y long t e n d o n s , t h e v e s s e l l i n e r , and i t s c l o s u r e s must be c a r e f u l l y s t u d i e d and designed t o e n s u r e t h a t i n - s e r v i c e i n s p e c t i o n i s p r a c t i c a l where r e q u i r e d .

T e c h n i c a l , economic and l i c e n s i n g e v a l u a t i o n and assessment i s n e c e s s a r y f o r t h e PCPV i n c l u d i n g t h e s l i d i n g upper cover and locking devices.

Submerged steam g e n e r a t o r development i s r e q u i r e d i n c l u d i n g s i n g l e t u b e , m u l t i t u b e and f u l l s c a l e development t e s t i n g of f l o w s t a b i l i t y and t r a n s i e n t r e s p o n s e ; d i s a s s e m b l y , c l e a n i n g and plugging p r o c e d u r e s .

Wet t h e r m a l i n s u l a t i o n f o r t h e primary c o o l a n t system and PCPV r e q u i r e s f u r t h e r development and d e m o n s t r a t i o n t e s t i n g .

Development and t e s t i n g of t h e r e f u e l i n g t u r n t a b l e component h a n d l i n g t o o l s , and o t h e r f e a t u r e s of underwater maintenance,

3-14

are needed. A l s o , corrosion product transport and activation are likely to differ from the standard PWR and may complicate maintenance. 9.

Economic evaluation must be performed comparing against coal and conventional LWRs. This evaluation must include a capital investment cost estimate for U.S. siting. Planned and realistically estimated forced outage rates must be evaluated against refueling and maintenance requirements and the spectra of potential plant unavailabilities. Extended testing of components is recommended in borated coolant conditions.

10.

Planned outage rates and realistically estimated forced outage rates must be evaluated against refueling and maintenance requirements and other potential plant unavailabilities. Extended testing of components is recommended under borated coolant conditions.

11.

Development and demonstration testing are needed for the multi-service pressurizer and the integrated control system for three reactor-steam generator modules feeding one or more turbine-generator sets.

12.

Confirmatory tests and analysis will be required to assure adequate negative reactivity feedback and the effective operation of the soluble boron control system.

3.3.2 3.3.2.1

The Small Advanced BWR Description

A small Boiling Water Reactor (BWR) design concept5 has been developed by the General Electric Company (GE). This concept attempts to maximize the use of BWR design, technology, and operating experience. Significant innovations are included to simplify and improve the performance of safety functions. These, as well as other system simplifications and a reduced power rating, are claimed to reduce total costs and speed construction. The major emphasis by GE has been on a 600 MW(e) concept which is judged to be adequately competitive with coal to interest the U. S. market. Lower power ratings are possible. A 1000 MW(e) concept is feasible but would require a larger volume suppression pool to maintain an equivalent time for operator response as in the 600 W(e) concept. The small BWR concept (Fig. 3.4) uses an isolation condenser to improve transient response. Control rods, which can be driven either electrically or with accumulator pressure, and gravity-driven borated water injection from an elevated low pressure pool are used to simplify and provide diversity to the shutdown function. Core cooling and decay heat removal are provided by depressurizing the reactor to the elevated

3-15

ORNL-DWG 85 -9578 UPPER STRUCTURE RELIEF

II CONTAINMENT STRUCTURE

UPPER CONTAINMENT OVERPRESSURE RELIEF \

YrnURE

DEPRESSURIZATION LOW PRESSURE LONG-TERM

YEUP

IS0U T ION CONDENSER

LOW PRESSURE ELEVATED POOL

FGRAVITY DRIVEN EMERGENCY CORE COOLING AND LIQUID POISON BACK'-UP

REACTOR CORE

DRIVES

Fig. 3 . 4 .

STEAM INJECTOR

A small BWR concept.

3-16 s u p p r e s s i o n pool. The d r y w e l l and pool gas s p a c e s are i n e r t . In addit i o n , a steam i n j e c t o r i s used t o improve f e e d w a t e r a v a i l a b i l i t y by prov i d i n g a c o n t i n u o u s minimum flow from a c o n d e n s a t e s t o r a g e t a n k even i f t h e main f e e d w a t e r pumps are l o s t . Steam i s produced i n t h e r e a c t o r v e s s e l i n a manner s i m i l a r t o t h a t of c u r r e n t BWRs. I n t e r n a l r e c i r c u l a t i o n pumps similar t o t h o s e used i n ABWR are used t o c i r c u l a t e water through t h e core. (At lower power The steam-water l e v e l s , n a t u r a l c i r c u l a t i o n becomes a b e t t e r c h o i c e . ) m i x t u r e e x i t i n g t h e c o r e i s d i r e c t e d t o s e p a r a t o r s and d r y e r s . Bottom-mounted c o n t r o l rod d r i v e s , s i m i l a r t o t h o s e used on t h e ABWR, a r e used t o p r o v i d e power s h a p i n g and emergency shutdown. R e a c t o r p r e s s u r e i s normally c o n t r o l l e d w i t h t u r b i n e t h r o t t l e and bypass valves. When t h e r e a c t o r v e s s e l i s i s o l a t e d from t h e t u r b i n e condenser, an i s o l a t i o n condenser c o n t r o l s p r e s s u r e . This d e v i c e w a s s e l e c t e d because of i t s s i m p l i c i t y and because i t p r o v i d e s high p r e s s u r e F a i l u r e of t h e i s o l a t i o n condenser r e a c t o r water i n v e n t o r y c o n t r o l . f u n c t i o n ( t o c o n t r o l r e a c t o r p r e s s u r e ) is not expected d u r i n g t h e p l a n t life. The a v a i l a b i l i t y of t h e p r e s s u r e c o n t r o l f u n c t i o n i s t o be a c h i e v e d by s e l e c t i n g an a p p r o p r i a t e redundancy i n t h e i s o l a t i o n cond e n s e r u n i t s and by u s i n g t h e s a f e t y v a l v e s / s t e a m i n j e c t o r as t h e d i v e r s e backup p r e s s u r e / i n v e n t o r y c o n t r o l system. However, i f such a f a i l u r e o c c u r s , s a f e t y and d e p r e s s u r i z a t i o n v a l v e s p r o v i d e a backup dep r e s s u r i z a t i o n t o t h e s u p p r e s s i o n p o o l which i s p o s i t i o n e d above t h e reactor vessel. When t h e r e a c t o r p r e s s u r e i s s u f f i c i e n t l y low, check v a l v e s open i n t h e s u p p r e s s i o n pool-to-vessel f i l l l i n e s and water f l o w s by g r a v i t y i n t o t h e r e a c t o r v e s s e l t o keep t h e c o r e covered. The res p o n s e s t o a loss-of-coolant a c c i d e n t and a t r a n s i e n t w i t h f a i l u r e t o scram are s i m i l a r . The s u p p r e s s i o n pool c o n t a i n s b o r a t e d water t o p r o v i d e a d i v e r s e backup t o t h e c o n t r o l rods. Core c o o l i n g and decay h e a t removal i s ass u r e d w i t h water r e t u r n e d t o t h e r e a c t o r v e s s e l and steam produced by decay h e a t i s vented t o t h e s u p p r e s s i o n pool. I n t h e 600 MW(e) c o n c e p t , No t h e r e i s a three-day supply of water a v a i l a b l e t o a c c e p t decay h e a t . operator action is required during t h i s t i m e . For l o n g e r p e r i o d s t h e s u p p r e s s i o n pool must be r e f i l l e d from an a s s u r e d s o u r c e w i t h h i g h l y rel i a b l e equipment. Emergency d i e s e l g e n e r a t o r s and c o r e c o o l i n g pumps are not required. With t h e above-mentioned s a f e t y f e a t u r e s , a s e v e r e a c c i d e n t i s extremely u n l i k e l y . The a b i l i t y t o r e t a i n f i s s i o n p r o d u c t s i n t h e supp r e s s i o n pool i s an i m p o r t a n t BWR f e a t u r e which h a s been r e t a i n e d t o p r o v i d e m i t i g a t i o n of s e v e r e a c c i d e n t s . Use of simple s a f e t y d e v i c e s , a c t i v a t e d by s t o r e d energy and u s e of i n h e r e n t p r o c e s s e s such as n a t u r a l c i r c u l a t i o n and g r a v i t y - f e d water d e l i v e r y t o t h e c o r e , reduce c o s t s through m o d u l a r i z a t i o n and system e l i m i n a t i o n . The l i c e n s i n g p r o c e s s may be s i m p l i f i e d .

â&#x20AC;&#x2122;

3-17 The f o l l o w i n g o b j e c t i v e s were e s t a b l i s h e d by GE f o r t h e Small BWR concept t o a s s u r e t h a t i t would be p r a c t i c a l and t h a t enhanced p e r f o r mance, economy, and s a f e t y would be achieved. 1.

The major power-producing elements of t h e concept are based on proven technology o r minor e x t e n s i o n s of c u r r e n t technology.

The key s a f e t y f u n c t i o n s are m a i n t a i n e d a t a l l times d u r i n g t r a n s i e n t and a c c i d e n t c o n d i t i o n s :

There i s no need f o r s h o r t - t e r m t e r m i s d e f i n e d as t h r e e days. t o r a c t i o n s which are r e q u i r e d accomplish. With such o p e r a t o r t i o n s w i l l be m a i n t a i n e d f o r an

S a f e t y d e v i c e s o r f e a t u r e s are e i t h e r i n h e r e n t t o t h e concept o r r e l y on t h e use of s t o r e d energy f o r motive power.

E x t e n s i v e t e s t i n g i s not r e q u i r e d . T h i s i s d e f i n e d as t a k i n g less t h a n t h r e e y e a r s t o prove t h e concept by The f i r s t commercial a p p l i c a t e s t i n g i t s new f e a t u r e s . t i o n i s t o s e r v e as a d e m o n s t r a t i o n u n i t , and a unique d e m o n s t r a t i o n i s n o t t o be r e q u i r e d .

operator action. ShortA f t e r t h i s p e r i o d , operashould be judged e a s y t o a c t i o n , t h e s a f e t y funci n d e f i n i t e period.

The d e s i g n i s c a p a b l e of m o d u l a r i z a t i o n t o a l l o w f a c t o r y fabr i c a t i o n and t e s t i n g of most major components.

The d e s i g n p e r m i t s a p l a n t c o n s t r u c t i o n p e r i o d of f o u r y e a r s .

C a p i t a l c o s t s are minimized s o e l e c t r i c i t y g e n e r a t i o n c o s t s are c o m p e t i t i v e with t h o s e of c o a l - f i r e d p l a n t s of s i m i l a r power r a t i n g s

These concept o b j e c t i v e s were e s t a b l i s h e d by GE w i t h t h e g o a l of achievi n g h i g h c o n f i d e n c e t h a t t h e f i n a l d e s i g n w i l l produce t h e r e q u i r e d power i n a manner which enhances s a f e t y i n a r e a d i l y d e m o n s t r a b l e way s o t h a t t h e l i c e n s i n g e f f o r t can be s i m p l i f i e d .

3.3.2.2.

C l a i m s , Advantages, and Disadvantages E v a l u a t e d A g a i n s t C r i t e r i a . E s s e n t i a l and D e s i r a b l e C h a r a c t e r i s t i c s

The p r o p o n e n t ' s claims and concept a d v a n t a g e s are d i s c u s s e d b r i e f l y as f o l l o w s f i r s t i n t h e o r d e r of t h e c r i t e r i a and t h e n t h e c h a r a c t e r i st i c s :

P u b l i c Risk: The Small BWR a p p e a r s t o be r e s i s t a n t t o f u e l damage under a l l a n t i c i p a t e d t r a n s i e n t s and f o r l o n g p e r i o d s ( 3 days) w i t h o u t human i n t e r v e n t i o n o r active e n g i n e e r e d s a f e t y f e a t u r e s a f t e r worst c a s e a c c i d e n t s .

3-18

Investment Risk: The small BWR a p p e a r s t o have a high d e g r e e of c o r e damage r e s i s t a n c e . The p r o b a b i l i t y f o r l o s s of i n vestment due t o c o r e melt would a p p e a r t o be less t h a n p l a n t y e a r (GE claims t o have a p r e l i m i n a r y PRA t o s u p p o r t less t h a n 10-6/plant y e a r ) . The p r o b a b i l i t y of high a v a i l a b i l i t y through r e s i s t a n c e t o long shutdowns from u p s e t s o r major maintenance a p p e a r s t o be f a v o r a b l e f o r t h e small BWR. T h i s c o n f i d e n c e d e r i v e s i n p a r t from t h e s i m i l a r i t y t o c u r r e n t BWRs and t h e i r e x t e n s i v e base of o p e r a t i n g e x p e r i e n c e . The s m a l l BWR has no e x t e r n a l r e c i r c u l a t i o n p i p i n g t o be s u b j e c t t o stress c o r r o s i o n c r a c k i n g , but a b o r a t i o n t r a n s i e n t w i l l r e q u i r e d e b o r a t i n g t h e primary system t o a c c e p t a b l e l e v e l s . GE i n t e n d s t o e n s u r e t h a t t h i s t r a n s i e n t w i l l be a v e r y low p r o b a b i l i t y e v e n t ( l e s s t h a n once i n p l a n t l i f e ) .

Economic C o m p e t i t i v e n e s s : Based on GE s t u d i e s t o d a t e , t h e Small BWR i s e s t i m a t e d t o be n e a r l y c o m p e t i t i v e w i t h c o a l a t 600 MW(e); however, GE b e l i e v e s t h a t t h e r e are as y e t une x p l o r e d o p t i o n s t o improve economic c o m p e t i t i v e n e s s . However, t h e d e s i g n i s t o o p r e l i m i n a r y f o r d e f i n i t i v e e v a l u a t i o n of c o n s t r u c t i o n c o s t s . Fuel c y c l e c o s t s s h o u l d d e r i v e e a s i l y from p a s t BWR experience as s h o u l d plant availability.

P r o b a b i l i t y of Cost/Schedule Overruns: identified.

Licensability: The l i c e n s a b i l i t y of t h i s concept i s enhanced by i t s s i m i l a r i t y t o c u r r e n t BWRs and by GEâ&#x20AC;&#x2122;s p l a n s t o t a k e no For example, t h e e x c e p t i o n s t o t h e General Design Criteria. concept i n c l u d e s t h e use of containment and c o n t r o l r o d s . T h i s approach i s e x p e c t e d t o minimize p o t e n t i a l l i c e n s i n g d i f ficulties.

Demonstration of Readiness: GE b e l i e v e s t h a t t h e p a s s i v e l y s a f e BWR r e p r e s e n t s o n l y a small e v o l u t i o n a r y e x t e n s i o n of e x i s t i n g technology needing only about two y e a r s f o r R&D d e m o n s t r a t i o n t e s t i n g and a n o t h e r two y e a r s t o complete t h e design. R&D c o s t s a r e e s t i m a t e d by GE a t about $3M b u t t h i s T h e i r t o t a l d e s i g n development c o s t i s f i g u r e may be low. roughly between $100M and $300M. The f i r s t p l a n t may be acc e p t a b l e f o r commercial o p e r a t i o n a f t e r s e r v i n g as t h e demons t r a t i o n . GE b e l i e v e s t h a t because t h e c o n c e p t r e l i e s h e a v i l y on e x i s t i n g technology and a l r e a d y developed d e s i g n s , t h e r e i s no need f o r l o n g term, e x t e n s i v e t e s t i n g . Therefore, a plant of t h i s t y p e could be a v a i l a b l e e a r l i e r t h a n t h e 2000-2010 t i m e frame.

Owner Competence: The small BWR should be amenable t o ready ease of o p e r a t i o n by e x p e r i e n c e d BWR o w n e r / o p e r a t o r s .

Essential Characteristics: As i n t h e case of PIUS, t h e small BWR has a good d e a l of promise t o p r o v i d e s a f e , r e l i a b l e and

No s p e c i f i c advantage

3-19 U n l i k e PIUS, t h e s m a l l BWR can be economic e l e c t r i c a l power. compared more d i r e c t l y t o i t s e v o l u t i o n a r y a n t e c e d e n t s i n t h e l a r g e BWR. From t h e s t a n d p o i n t of c h a r a c t e r i s t i c s a f f e c t i n g c o n s t r u c t i b i l i t y , c o s t and o p e r a b i l i t y , t h e comparison b r e a k s down because of i n s t i t u t i o n a l r e a s o n s , f o r example, t h e h i s t o r y of problems i n t h e U.S. BWR e x p e r i e n c e compared t o successes i n t h e J a p a n e s e BWR i n d u s t r y . GE r e c o g n i z e s t h i s d i f f e r e n c e i n h i s t o r i c a l p e r s p e c t i v e s but o f f e r s no s p e c i f i c a r guments t h a t t h e sought a f t e r c h a r a c t e r i s t i c s l i s t e d i n Chapter 2 w i l l be r e a l i z e d f o r t h e small BWR i n t h e U.S. In p r i n c i p l e , a t t h i s e a r l y s t a g e of development, most of t h e e s s e n t i a l c h a r a c t e r i s t i c s can be a s c r i b e d t o t h e small BWR c o n c e p t b e c a u s e of i t s enhanced r e l i a n c e on p a s s i v e s a f e t y and d e s i g n s i m p l i f i c a t i o n ; however, t h e e l e v a t e d pool may impose s t r e n u o u s seismic r e q u i r e m e n t s and more c o m p l i c a t e d c o n s t r u c t i o n which can i n c r e a s e c o s t .

Desirable Characteristics: Because of t h e e v o l u t i o n a r y n a t u r e of t h e d e s i g n , t h e few and p r a c t i c a l RD&D r e q u i r e m e n t s are t h e most s a l i e n t c h a r a c t e r i s t i c .

The p o t e n t i a l d i s a d v a n t a g e s are d i s c u s s e d as f o l l o w s :

No s p e c i f i c d i s a d v a n t a g e i d e n t i f i e d .

P u b l i c Risk:

Investment Risk:

Economic C o m p e t i t i v e n e s s :

No s p e c i f i c d i s a d v a n t a g e i d e n t i f i e d .

The c o s t c o m p e t i t i v e n e s s of t h e small 600 MW(e) BWR i s n o t y e t demonstrated because t h e GE a n a l y s i s , which i s s t a t e d t o be v e r y p r e l i m i n a r y , f i n d s t h e lower r a t i n g of t h e small BWR somewhat s h o r t of breakeven w i t h e q u i v a l e n t coal-fired units. When o t h e r p o t e n t i a l c o s t s a v i n g s are a n l y z e d , GE e x p e c t s t h e d e s i g n t o be c o m p e t e t i v e w i t h coal. GE a g r e e s t h a t more d e t a i l e d c a l c u l a t i o n s are i n o r d e r and t h a t i n d e p e n d e n t e v a l u a t i o n s are d e s i r a b l e .

On-line r e f u e l i n g i s n o t p o s s i b l e f o r t h e small BWR, and s o r e f u e l i n g shutdowns must be s c h e d u l e d as i n c u r r e n t LWRS

P r o b a b i l i t y of Cost/Schedule Overruns: No s p e c i f i c disadvant a g e i d e n t i f i e d ; however, t h e d e s i g n i s i n a v e r y p r e l i m i n a r y state. I d e n t i f i a b l e i m p o r t a n t needs which r e q u i r e a t t e n t i o n are a s u i t a b l e water l e v e l i n d i c a t o r and a r e l i a b l e d e p r e s s u r i z a t i o n system.

Licensability:

As w i t h a l l advanced r e a c t o r s , t h e small BWR h a s n o t y e t been f o r c e d t o a d d r e s s post-TMI l i c e n s i n g p r o c e e d i n g s .

3-20

However, GE i s aware of post-TMI r e q u i r e m e n t s and p l a n s t o r e f l e c t them i n t h e f i n a l d e s i g n . The p o s s i b i l i t y e x i s t s f o r t h e need t o a d d r e s s t h e p r o b a b i l i s t i c r i s k s of t h e consequences of beyond d e s i g n b a s i s a c c i d e n t s coupled t o t h e c o s t - b e n e f i t of a d d i n g equipment t o a v e r t t h e r i s k a s s o c i a t e d w i t h such v e r y low p r o b a b i l i t y a c c i d e n t s . GE f e e l s t h a t r e t e n t i o n of t h e s u p p r e s s i o n pool and i t s a b i l i t y t o r e t a i n f i s s i o n p r o d u c t s a f t e r a s e v e r e accid e n t w i l l be of b e n e f i t i n a n a l y s i s of such a c c i d e n t s . The r e g u l a t o r y a u t h o r i t i e s may impose t h e use of seconda r y p l a n t man-rated s h i e l d i n g f o r power o p e r a t i o n , a d e d i c a t e d 30-day water s u p p l y f o r t h e s u p p r e s s i o n p o o l , enhanced s a f e t y - g r a d e c o n t r o l room beyond t h a t planned by GE, a n d / o r d e d i c a t e d emergency ac e l e c t r i c a l power. GE i n t e n d s t o r e l y s o l e l y on emergency d c s o u r c e s w i t h t h e g r a v i t y d r a i n ECCS and a r g u e s t h a t diesel-powered pumps on a f i r e e n g i n e t r u c k could p r o v i d e water t o t h e supp r e s s i o n pool a f t e r 3 days. Although GE acknowledges t h a t t h e r e are some l i c e n s i n g r i s k s w i t h p o t e n t i a l f o r c o s t i n c r e a s e s , GE a l s o c o n t e n d s t h a t t h i s p o t e n t i a l app e a r s r e l a t i v e l y small. b.

Need f o r area e v a c u a t i o n a l s o i s n o t f i r m l y e s t a b l i s h e d f o r t h e s m a l l BWR, b u t GE f e e l s t h a t t h e y can make a good case f o r a v o i d i n g area e v a c u a t i o n based on e x p e c t e d performance a t lower power d e n s i t y and w i t h e x p e c t e d f i s s i o n p r o d u c t r e t e n t i o n i n t h e s u p p r e s s i o n pool.

Demonstration P l a n t :

Owner Competence:

Essential Characteristics: Although a d e q u a t e l y s a f e by curr e n t d e s i g n s t a n d a r d s and r e g u l a t i o n s , BWRs have been s i g n i f i c a n t c o n t r i b u t e r s t o r a d i o a c t i v e e f f l u e n t releases. Better f u e l - c l a d performance and improved water c h e m i s t r y have subs t a n t i a l l y decreased t h e r e l e a s e s . The u s e of b a r r i e r f u e l and lower power d e n s i t i e s as proposed s h o u l d f u r t h e r r e d u c e the radioactive effluents. C o n s t r u c t i o n of t h e e l e v a t e d p o o l and t h e a t t e n d a n t c o n c e r n about seismic r e s p o n s e must be add r e s s e d f u l l y as planned i n t h e proposed R&D.

Desirable Characteristics: The s m a l l BWR o f f e r s no new f e a t u r e s w i t h r e g a r d t o o n - l i n e r e f u e l i n g , p r o l i f e r a t i o n res i s t a n c e , decommissioning o r waste h a n d l i n g and d i s p o s a l . The c o n c e r n s and problems are comparable t o c u r r e n t g e n e r a t i o n LWRs and i n many i n s t a n c e s s h a r e d w i t h o t h e r advanced o r innovative designs. Although t h e o b j e c t i v e i s t o have a r e m o t e l y c o n t r o l l e d secondary p l a n t w i t h no o n - s t a t i o n o p e r a t o r s n e a r p o t e n t i a l l y c o n t a m i n a t a b l e steam l i n e s , t h e small BWR s h a r e s t h e same c h a r a c t e r i s t i c s of t h e l a r g e BWRs i n h a v i n g r a d i o a c t i v i t y i n t h e steam l i n e s which can l e a d t o t h e p o t e n t i a l

No s p e c i f i c d i s a d v a n t a g e i d e n t i f i e d .

3-21 f o r h i g h e r o c c u p a t i o n a l e x p o s u r e s compared t o o t h e r reactors. The improvements d e s c r i b e d i n S e c t i o n 8 above a l s o a p p l y here.

3.3.2.3

R&D Needs and Open Q u e s t i o n s E v a l u a t e d

A f u l l h e i g h t d e m o n s t r a t i o n t e s t i s needed of t h e g r a v i t y d r a i n Emergency Core Cooling System (ECCS) from t h e e l e v a t e d low p r e s s u r e pool ( t h o u g h t t o be an i t e m of concern t o NRC licensing).

High flow steam i n j e c t o r d e m o n s t r a t i o n t e s t i n g i s n e c e s s a r y ; t h e d e s i g n i s based on low flow t e s t s performed o v e r 10 y e a r s ago. Also, t h e r e l i a b i l i t y and a v a i l a b i l i t y of t h e i n j e c t o r A key component of t h e c o n t r o l system must be d e m o n s t r a t e d . i n j e c t o r c o n t r o l system i s a s u f f i c i e n t l y a c c u r a t e v e s s e l water l e v e l i n d i c a t i o n . GE c o n t e n d s t h a t i n j e c t o r c o n t r o l d o e s n o t r e q u i r e f i n e i n d i c a t i o n of v e s s e l water l e v e l , which may w e l l be t h e case, but d e m o n s t r a t i o n t e s t i n g i s f e l t t o be required t o assure t h a t the i n j e c t o r is a legitimate benefit t o p l a n t s a f e t y and enhanced a v a i l a b i l i t y . A p o t e n t i a l buyer may r e q u i r e a s s u r a n c e b e f o r e b e i n g s o l d a p r o d u c t t h a t could c a u s e d e l a y , rework o r even removal i f i t were t o f a i l d u r i n g h o t f u n c t i o n a l tests on t h e completed p l a n t . GE n o t e s however t h a t " i n t h e worst case", t h e steam i n j e c t o r could be d e l e t e d from t h e d e s i g n , and a n e a r l y e q u i v a l e n t l e v e l of p r o t e c t i o n c o u l d be added by i n c r e a s i n g t h e redundancy of t h e i s o l a t i o n c o n d e n s e r , o r by r e v e r t i n g t o t h e u s e of t h e steam d r i v e n R e a c t o r Core I s o l a t i o n Cooling (RCIC) system now i n use a t o p e r a t i n g BWRs.

C o n f i r m a t i o n of t h e a n a l y t i c a l l o a d d e f i n i t i o n f o r h o r i z o n t a l The v e n t d i s c h a r g e s t o a covered s u p p r e s s i o n pool i s needed. c o v e r e d pool r e s u l t s i n t h e need f o r l o a d d e f i n i t i o n s up t o a d i f f e r e n t i a l p r e s s u r e of about 0.35 MPa (40-50 p s i ) compared t o t h e c u r r e n t l y a v a i l a b l e t e s t d a t a up t o 0.1 MPa ( 1 5 p s i ) . However, such t e s t i n g is a l r e a d y planned f o r t h e advanced BWR i n 1986, and t h e r e s u l t s of t h a t program can be u t i l i z e d f o r t h e 600 MW(e) p l a n t . GE c o n s i d e r s t h i s work t o be c o n f i r m a t o r y r a t h e r t h a n R&D and s o does n o t f a c t o r t h i s i n t o t h e i r R&D c o s t estimates.

D e p r e s s u r i z a t i o n v a l v e d e m o n s t r a t i o n i s needed; t h e d e s i g n i s based on a concept of a v a l v e which i s d e e n e r g i z e d t o open and t h e n l a t c h e s open. Although t h e d e s i g n i s s i m p l e i n c o n c e p t , i t a p p a r e n t l y has never ( o r not w i d e l y ) been a p p l i e d i n pract i c e . Most LWRs u s e e l e c t r i c o r a i r o p e r a t e d v a l v e s which are t y p i c a l l y d e s i g n e d t o f a i l s h u t ; i n t h e s m a l l BWR, r e a c t o r p r e s s u r e opens t h e v a l v e s a g a i n s t a m a g n e t i c f o r c e which is l o s t when t h e dc c i r c u i t s are d e e n e r g i z e d . GE c o n s i d e r s a i r o p e r a t e d v a l v e s t o be t h e b e s t backup a l t e r n a t i v e t o t h e magn e t i c valve, but t h i s option appears t o reduce t h e p a s s i v i t y of t h e s a f e t y f e a t u r e .

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3.4 3.4.1

Independent, i s needed.

Thorough seismic a n a l y s i s i s needed t o a s s u r e t h e i n t e g r i t y of t h e e l e v a t e d p o o l s and a s s o c i a t e d piping, valves, and containment s t r u c t u r e s .

d e t a i l e d e v a l u a t i o n of p l a n t economics and c o s t s

L I Q U I D METAL COOLED REACTORS (LMRs)

Introduction

The t h r e e IMR c o n c e p t s e v a l u a t e d by NPOVS are t h e Large S c a l e P r o t o t y p e Breeder (LSPB) , t h e Sodium Advanced F a s t Reactor ( S U R ) , and t h e Power Reactor I n h e r e n t l y S a f e Module (PRISM). To place t h e d i s c u s s i o n of t h e s e d e s i g n s i n p e r s p e c t i v e , t h i s s e c t i o n b e g i n s w i t h a summary of major d e s i g n o p t i o n s , d e s i g n c h a l l e n g e s , and d e s i g n t r a d e o f f s envis i o n e d f o r commercial LMRs. This i s followed by a d e s c r i p t i o n of e a c h concept and a d i s c u s s i o n of t h e i r a d v a n t a g e s and d i s a d v a n t a g e s w i t h r e g a r d t o t h e NPOVS c r i t e r i a . To complete t h e s e c t i o n , t h e r e s e a r c h and development needs f o r t h e c o n c e p t s are p r e s e n t e d . 3.4.2

Design ODtions. C h a l l e n g e s . and T r a d e o f f s

R e c e n t l y , emphasis of t h e U.S. b r e e d e r program h a s s h i f t e d towards enhanced p a s s i v e s a f e t y , lower c a p i t a l and o p e r a t i n g c o s t s , s h o r t e r conT h i s l e d t o a reexaminas t r u c t i o n times, and enhanced l i c e n s a b i l i t y . 6 t i o n of t h e many d e s i g n o p t i o n s , c h a l l e n g e s , and t r a d e o f f s which are a v a i l a b l e f o r p u r s u i n g t h e LMR concepts. Those mentioned below are t h e more i m p o r t a n t ones with r e g a r d t o t h e NPOVS s t u d y . The u n i v e r s a l c h o i c e of sodium as t h e c o o l a n t f o r commercial LMRs r e s u l t s i n s e v e r a l d e s i g n o p t i o n s and d e s i g n c h a l l e n g e s , a l l of which r e l a t e t o t h e p h y s i c a l and chemical p r o p e r t i e s of s odium.^ Design o p t i o n s made p o s s i b l e by sodium which enhance p a s s i v e s a f e t y i n c l u d e : (1) a low-pressure primary system, ( 2 ) an o p e r a t i n g primary c o o l a n t t e m p e r a t u r e w e l l below b o i l i n g , ( 3 ) a l a r g e h e a t c a p a c i t y i n t h e c o o l a n t volume, (4) r e l a t i v e l y low c o o l a n t v e l o c i t i e s and pumping powers, (5) a c o o l a n t which i s compatible w i t h p r e f e r r e d c l a d d i n g materials, and ( 6 ) n a t u r a l c i r c u l a t i o n h e a t t r a n s f e r l o o p s f o r decay h e a t removal. Design c h a l l e n g e s a s s o c i a t e d w i t h t h e use of sodium as t h e r e a c t o r coolant include: ( 1 ) p r o t e c t i o n a g a i n s t sodium f i r e s and sodium-water r e a c t i o n s , ( 2 ) c o n s i d e r a t i o n s of r e a c t i v i t y e f f e c t s a s s o c i a t e d w i t h l o s s - o f - c o o l a n t a c c i d e n t s , (3) m i n i m i z a t i o n of primary c o o l a n t a c t i v a t i o n by n e u t r o n a b s o r p t i o n , ( 4 ) m a i n t a i n i n g t h e c o o l a n t i n t h e l i q u i d s t a t e d u r i n g a c c i d e n t c o n d i t i o n s , (5) r e q u i r e m e n t s f o r n o n v i s i b l e ref u e l i n g , and ( 6 ) sodium p u r i t y m o n i t o r i n g and c l e a n u p . Through t h e many y e a r s of e x t e n s i v e r e s e a r c h , development, and e x p e r i e n c e w i t h sodium systems, d e s i g n t r a d e o f f s have been developed and demonstrated. To a g r e a t e x t e n t LMRs are a t t r a c t i v e because t h e y use sodium as a c o o l a n t ; many d e s i g n d e c i s i o n s are dominated by c o n s i d e r a t i o n s of sodium

3-23

properties. However, t h e U.S. u t i l i t y i n d u s t r y l a c k s f a m i l i a r i t y w i t h t h e use of sodium c o o l i n g technology, and t h i s f a c t must be reckoned w i t h i n s e c u r i n g u t i l i t y competence. Another s i g n i f i c a n t o p t i o n f o r ZMR d e s i g n s i s t h e r e q u i r e d power o u t p u t and t h e r e f o r e t h e s i z e of t h e r e a c t o r c o r e . Presently, a l a r g e c o r e producing about 3500 MW(t) o f f e r s p l a n t economy of scale and r e l a t i v e s i m p l i c i t y of r e a c t o r c o n t r o l compared t o m u l t i p l e modules. C l a i m s a s s o c i a t e d w i t h producing t h e same power w i t h s e v e r a l smaller cores includes construction advantages associated with factory f a b r i c a t i o n , enhanced p a s s i v e s a f e t y a g a i n s t c o r e d i s r u p t i v e a c c i d e n t s , and g r e a t e r f l e x i b i l i t y i n t h e d e s i g n of p a s s i v e decay h e a t removal s y s tems. I n a d d i t i o n , s a f e t y c h a r a c t e r i s t i c s of t h e s e smaller c o r e s can be demonstrated i n f u l l - s c a l e p r o t o t y p i c t e s t s , t h e r e b y s t r e n g t h e n i n g licensing positions. Other claims made f o r smaller, m u l t i p l e c o r e s f o r each power s t a t i o n i n c l u d e lower investment r i s k , a b e t t e r match of comp l e t i o n s c h e d u l e s w i t h l o a d demands, and h i g h a v a i l a b i l i t y . The NPOVS assessment i n c l u d e s c o n s i d e r a t i o n of t h e e n t i r e f u e l cycle. A once-through c y c l e does n o t t a k e advantage of t h e p o t e n t i a l f o r LMRs t o breed and t h u s p r o v i d e g r e a t l y extended f u e l r e s e r v e s . Fuel rec y c l e i s a n t i c i p a t e d when i t becomes c o s t e f f e c t i v e and w i l l be r e q u i r e d f o r a long-term n u c l e a r c a p a b i l i t y . Design o p t i o n s which most i n f l u e n c e f u e l r e c y c l e i n c l u d e l o n g l i f e c o r e s and t h e f u e l type. Oxide f u e l h a s been t h e r e f e r e n c e f o r a l l f o r e i g n and domestic programs, b u t , r e c e n t l y , metal f u e l h a s been reexamined a t t h e Argonne N a t i o n a l Laboratory. See Appendix E f o r d i s c u s s i o n of f u e l c y c l e s f o r o x i d e and metal f u e l s . However, o t h e r concerns such as s a f e g u a r d s , t h e a v a i l a b i l i t y of f u e l from enrichment o r r e p r o c e s s i n g f a c i l i t i e s , t h e c o s t and l i c e n s a b i l i t y of t h e s e f a c i l i t i e s , and p u b l i c and u t i l i t y a c c e p t a n c e must be considered. Thus, a major b u s i n e s s d e c i s i o n f o r b u i l d i n g an LMR may be v e r y dependent on having an a c c e p t a b l e and a v a i l a b l e f u e l - s u p p l y system.

Two d e s i g n o p t i o n s have t r a d i t i o n a l l y e x i s t e d f o r t h e c o n f i g u r a t i o n of t h e primary l o o p i n a commercial ZMR. The f i r s t i s a pool d e s i g n f o r which t h e c o r e , i n t e r m e d i a t e h e a t exchanger, and remainder of t h e p r i mary system are a l l c o n t a i n e d w i t h i n a s i n g l e v e s s e l . The second i s a loop d e s i g n where o n l y t h e r e a c t o r c o r e i s placed i n t h e s o d i u m - f i l l e d r e a c t o r v e s s e l ; t h e primary pump and i n t e r m e d i a t e h e a t exchanger are o u t s i d e t h i s v e s s e l , being i n c o r p o r a t e d i n t o a h e a t t r a n s f e r loop. The c h o i c e of a l o o p o r pool o p t i o n i s s i g n i f i c a n t s i n c e i t h a s a major A r e c e n t worldwide i n f l u e n c e on t h e remainder of t h e p l a n t d e s i g n . emphasis t o d e c r e a s e t h e c a p i t a l c o s t s p r o j e c t e d f o r commercial LMRs h a s focused a t t e n t i o n on t h e pool d e s i g n , which g e n e r a l l y o f f e r s an advant a g e i n compactness.8

3.4.3

Design D e s c r i p t i o n s

T h i s b r i e f d i s c u s s i o n of t h e LSPB, SAFR, and PRISM d e s i g n s i n c l u d e s p l a n t c h a r a c t e r i s t i c s which s u p p o r t claims c o n c e r n i n g economics, s a f e t y ,

3-24

l i c e n s a b i l i t y , c o n s t r u c t i b i l i t y , and p u b l i c a c c e p t a n c e . Table 3.1 prov i d e s a summary l i s t of t h e more i m p o r t a n t f e a t u r e s of each d e s i g n as p r e s e n t e d i n t h e r e f e r e n c e s t o t h i s r e p o r t and updated by t h e d e s i g n e r s . 3.4.3.1

The Large S c a l e P r o t o t y p e Breeder (LSPB)

T h i s d e s i g n e f f o r t i s a s s i s t e d by s e v e r a l c o n t r a c t o r s s p o n s o r e d by t h e U.S. Department of Energy and, s i n c e 1982, by t h e E l e c t r i c Power R e s e a r c h I n s t i t ~ t e . ~ - l It ~ i s i n t e n d e d t o p r o v i d e t h e p r o t o t y p e of a commercially d e p l o y a b l e p l a n t which could produce power b e f o r e t h e y e a r 2000. P r e l i m i n a r y d e s i g n of a f o u r - l o o p c o n f i g u r a t i o n i s completed and p r o v i d e s t h e b a s i s f o r our e v a l u a t i o n . P r e l i m i n a r y d e s i g n of a poolt y p e concept has been i n i t i a t e d . Of t h e LMR c o n c e p t s c o n s i d e r e d h e r e , t h e 1319-MW(e) LSPB i s most e a s i l y a s s o c i a t e d with h i s t o r i c design evolutions. It i n c o r p o r a t e s many f e a t u r e s from p r e v i o u s LMFBR d e s i g n s , b o t h i n t h e United S t a t e s and abroad. I n a d d i t i o n , t h e LSPB i n c l u d e s d e s i g n i n n o v a t i o n s t o r e d u c e c a p i t a l and o p e r a t i n g c o s t s and enhance p a s s i v e s a f e t y . Thus, t h i s c o n c e p t , as p r e s e n t e d by t h e LSPB p r o j e c t , s a t i s f i e d t h e NPOVS ground rules.

A s i n d i c a t e d i n Table 3.1, e a c h of t h e f o u r l o o p s of t h e LSPB cons i s t s of a primary h e a t t r a n s f e r l o o p , an i n t e r m e d i a t e h e a t t r a n s p o r t The f o u r steam g e n e r a t o r s f e e d a l o o p , and a steam g e n e r a t o r system. s i n g l e t u r b i n e manifold. The r e a c t o r c o r e i s h e t e r o g e n e o u s u s i n g b o t h PuO2 and U02 as f u e l . A major d e s i g n g o a l of t h e LSPB h a s been c o s t c o m p e t i t i v e n e s s . 1 째 The t h i r d p l a n t c o n s t r u c t e d i s i n t e n d e d t o be e c o n o m i c a l l y c o m p e t i t i v e w i t h b o t h c o a l - f i r e d and LWR p l a n t s under t h e a s s u m p t i o n of no government s u p p o r t . S p e c i f i c f e a t u r e s i n c o r p o r a t e d t o enhance c o n s t r u c t i b i l i t y and reduce c a p i t a l and o p e r a t i n g c o s t s i n c l u d e : (1) t h e capability t o o p e r a t e a t reduced power u s i n g t h r e e l o o p s w h i l e t h e r e m a i n i n g l o o p undergoes maintenance, ( 2 ) s h a l l o w e x c a v a t i o n , ( 3 ) c l o s e - c o u p l i n g of major s y s t e m s f o r reduced l e n g t h s of l a r g e - d i a m e t e r sodium p i p i n g , ( 4 ) reduced s i z e s of major b u i l d i n g s t o r e d u c e c a p i t a l c o s t s of commodi t i e s such as c o n c r e t e and r e b a r , ( 5 ) use of c a b l e m u l t i p l e x i n g t o reduce c a b l e r e q u i r e m e n t s and e l i m i n a t e c a b l e s p r e a d i n g rooms, ( 6 ) preassembly of subsystems o n - s i t e p r i o r t o i n s t a l l a t i o n i n t h e p l a n t , ( 7 ) s e p a r a t i o n of t h e b a l a n c e - o f - p l a n t from t h e n u c l e a r i s l a n d , and (8) i n l i n e arrangement of major b u i l d i n g s t o enhance c o n s t r u c t i b i l i t y . Another s i g n i f i c a n t i n n o v a t i o n of t h e LSPB system i s t h e containment

*The

d e s i g n e f f o r t s by G e n e r a l E l e c t r i c , Rockwell I n t e r n a t i o n a l , Combustion E n g i n e e r i n g , Westinghouse, Burns & Roe, B e c h t e l and Stone & Webster are t e c h n i c a l l y i n t e g r a t e d by t h e The E l e c t r i c Power Research I n s t i t u t e C o n s o l i d a t e d Management O f f i c e f o r t h e LMFBR.

T a b l e 3.1.

Design and c o n s t r u c t i o n characteristics

Design and c o n s t r u c t i o n c h a r a c t e r i s t i c s of t h e LMR d e s i g n s selected for i n i t i a l investigations

LSPB Loop

SAFR

Power l e v e l [MW(e)l

1319 [3500 MW(th) and a n e t p l a n t e f f i c i e n c y of 37.6XJ

S i n g l e Power Pak, 350; M u l t i p l e Power P a k s , 700, 1050, 1400, e t c .

R e a c t o r E x i t Temperature ("c)

510

Mo used f o r 510 ( 9 Cr-1 e n t i r e intermediate system)

Steam Cycle and Steam C o n d i t i o n s ("C, MPa)

Benson c y c l e (454, 15.7), conventional

Benson c y c l e (457, 18.3), conventional

PRISM

S i n g l e r e a c t o r , 138; t h e smallest power block u n i t h a s t h r e e r e a c t o r s and one t u r b i n e , f o r 415. Station power w i t h m l t i p l e segments of 415, 830, o r 1245

Steam e n t e r s t h e t u r b i n e from a steam drum f e d by t h r e e steam g e n e r a t o r s . Steam i s a t s a t u r a t i o n c o n d i t i o n s (282, 6.6)

Plant Configuration

Four loops ( p o o l d e s i g n i s being d e v e l o p e d )

Pool ( e a c h Power Pak h a s one r e a c t o r and one turbine)

Pool ( t h r e e pool modules, each w i t h one r e a c t o r , f o r each t u r b i n e )

Number of Pumps i n Primary Loop(s)

Four (one p e r l o o p )

Two, i n primary v e s s e l of e a c h Power Pak

Four p e r module

N.umber of I n t e r m e d i a t e Heat Exchangers (IHXs) p e r Power Unit

Four (one p e r l o o p )

Four, i n primary v e s s e l of e a c h Power Pak, P r i mary flow i s g r a v i t y d r i v e n on t h e t u b e s i d e .

Four per module

Number of I n t e r m e d i a t e Loops p e r Power Unit

Four

Two, each w i t h i t s own Steam G e n e r a t o r , f o r each Power Pak

One p e r r e a c t o r module w i t h one steam g e n e r a t o r per r e a c t o r

w I

N lJl

Table 3.1.

Design and construction characteristics

Design and construction characteristics of the LMR designs selected for initial investigations (continued)

LSPB Loop*

SAF R

PRISM

Fue 1

U-Pu oxide

U-Pu oxide, or U-Zr metal, or U-Pu-Zr metal

U-Pu oxide or U-Pu-Zr metal

Reactor Shutdown System

Diverse, redundant system for active shutdown

Diverse, redundant system for active system

Passive rod release from Curie-point or other temperature effect as a design option

Self-activated, passive, temperature-induced release of these rods from Curie-point effect

Passive shutdown from negative reactivity feedback due to temperature increases and self actuated release 3f shutdown rods from over-temperature

w I

Shutdown Heat Removal

Normal: BOP using natural or forced circulation Dedicated: ' b o , independent, diverse, and redundant safety grade systems that remove heat directly from the reactor vessel to the atmosphere. One system uses natural circulation Backup: Cross-connection to the natural ciryulation heat removal system of the exvessel, fuel storage tanks

Normal: BOP with natural circulation. Investment Protection: Direct reactor auxiliary cooling (DRAC). Sodiumto-air heat transfer using natural circulation. Safety: Reactor air cooling system (RACS). Reactor guard vessel is cooled by natural circulation of air

Normal: Heat transport system to turbine-generator condenser Investment Protection: Air cooling of steam generator shell.

Safety: Radiant Vessel Auxiliary Cooling System (RVACS). A passive, radiant heat transfer, natural circulation sys tem that operates efficiently at high temperatures

Table 3.1.

Design and c o n s t r u c t i o n characteristics

Design and c o n s t r u c t i o n c h a r a c t e r i s t i c s of t h e LMR d e s i g n s selected for i n i t i a l investigations (continued)

SAFR

LSPB Loop*

PRISM

IHTS and BOP C o n f i g u r a t i o n

Modularization i s stressed. A rectangular r e a c t o r containment b u i l d i n g w i l l be used. Systems o u t s i d e c o n t a i n ment a r e of c o n v e n t i o n a l design

IHTS loops and components made of 9 Cr-1 Mo s t e e l . Conventional and nons a f e t y g r a d e , s e i s m i c I1 design.

High commercial g r a d e t o reduce c o s t . The r e a c t o r module and r e f u e l i n g equipment a r e of n u c l e a r s a f e t y grade.

F u e l Cycle F a c i l i t i e s and S t r a t e g y

Under-the-head reac o r refueling. Assumes o f f s i t e f u e l r e p r o c e s s ng *

On-site r e p r o c e s s i n g and r e f a b r i c a t i o n included i n d e s i g n l a y o u t but l i t t l e d e t a i l d e s i g n as yet. Spent f u e l i s s t o r e d f o r a year i n t h e primary vessel.

R e f u e l i n g u s i n g a mobile r e f u e l i n g machine which moves from one module t o t h e next. Reprocessing and r e f a b r i c a t i o n may t a k e p l a c e e i t h e r on- or o f f site.

C o n s t r u c t i o n Characteri s t i c s of Major Compon e n t s and S t r u c t u r e s

Modular c o n s t r u c t i o n w i l l be emphasized. Access plugs are provided i n t h e t o p of t h e containment b u i l d i n g f o r removal of l a r g e components.

Reactor assembly with v e s s e l s , i n t e r n a l s and deck i s f a c t o r y b u i l t Acand barge s h i p p a b l e . cess plugs provided i n t h e top of t h e c o n t a i n ment b u i l d i n g f o r removal of l a r g e components.

Reactor modules a r e shop f a b r i c a t e d and assembled and a r e r a i l shippable. I n add i t i o n , the intermediate sodium loop, t h e steam g e n e r a t o r , and o t h e r BOP systems w i l l be modularized and f a c t o r y produced.

Containmentfconfinement Building Characteristics

Reactor, PHTS, and a u x i l i a r y equipment i n a c o n c r e t e containment b u i l d i n g e n c l o s e d by a s t e e l confinement structure.

One containment b u i l d i n g f o r each Power Pak.

Each module has i t s own con t a i nme n t

N e t Thermal E f f i c i e n c y ( X )

37.6

36.7

32.5

Availability ( X )

80 ( d e s i g n )

>84 f o r a s i n g l e Power Pak.

88 e s t i m a t e d ; 80 used i n economi c a s s e s s m e n t s

w I

10 4

T a b l e 3.1.

Design and c o n s t r u c t i o n characteristics P l a n t Lifetime ( y r s )

Design and c o n s t r u c t i o n c h a r a c t e r i s t i c s of t h e LMR d e s i g n s selected f o r i n i t i a l investigations (continued)

LSPB Loop*

SAFR

PRISM

40 ( b u t r e a c t o r modules can be r e p l a c e d a t r e l a t i v e low c o s t )

He t erogeneou s 4.83 5.71 3 (4 f o r advanced c o r e )

Heterogeneous 3.25 4.04 4

Homogeneous 1.76 1.93

Core Design C h a r a c t e r i s t i c s a ) Type b) Height ( m e t e r s ) c) D i a m e t e r (meters) d) Resident t i m e i n core (yrs) e) Refueling I n t e r v a l s (y r s 1 f ) Cover g a s

Reactor Vessel a ) I D (meters) b) Height (meters)

14.6 19

11.9 14.5

5.8 (containment) 19.5

109

158

107

Doubling time of 25 y e a r s f o r breeder c o r e reload. Breeding i s not r e q u i r e d f o r t h e i n i t i a l core.

System w i l l need o n l y a f e e d of U-238 s i n c e Pu-239 needs w i l l be s u p p l i e d by conversion.

Breeding r a t i o of 1.04 f o r o x i d e f u e l and 1.22 f o r metal f u e l .

Breeding C a p a b i l i t y

*The

4 w I

N 03

LSPB pool concept h a s s i m i l a r c h a r a c t e r i s t i c s but o f f e r s a h i g h e r power l e v e l and p l a n t e f f i c i e n c y 11350 MW(e) and 38.5%] and improved shutdown h e a t removal. It a l s o w i l l r e q u i r e a l a r g e r v e s s e l (19 m I D , 21 m H).

3-29 d e s i g n which i s a r e c t a n g u l a r , s t e e l - l i n e d , c o n c r e t e b u i l d i n g w i t h roof h a t c h e s f o r c o n s t r u c t i o n and maintenance. Adjacent n u c l e a r i s l a n d b u i l d i n g s are i n t e g r a l w i t h t h e containment t h e r e b y p r o v i d i n g c o s t e f f e c t i v e containment and confinement c a p a b i l i t i e s . The e x t e n t t o which t h e LSPB d e s i g n h a s a c h i e v e d lower c a p i t a l c o s t s i s s u g g e s t e d by The LSPB p l a n t , w h i l e producing f o u r comparison t o t h e CRBRP d e s i g n . times t h e n e t e l e c t r i c a l power of t h e CRBRP d e s i g n , o c c u p i e s a n u c l e a r i s l a n d which i s p h y s i c a l l y smaller t h a n t h a t of CRBRP. Finally an o p t i o n h a s been m a i n t a i n e d t o u s e a f u e l d e s i g n e d f o r c o s t performance by r e d u c i n g t h e b r e e d i n g s p e c i f i c a t i o n . These d e s i g n s t u d i e s i n d i c a t e d t h a t f u e l c y c l e c o s t s could be reduced by a b o u t 3 mills/kWh. Design m o d i f i c a t i o n s under c o n s i d e r a t i o n could enhance i n h e r e n t p r o t e c t i o n f o r f a i l u r e - t o - s c r a m e v e n t s through temperature-induced exp a n s i o n of c o n t r o l rod d r i v e - l i n e s o r temperature-induced c o n t r o l rod releases o r o t h e r Self A c t u a t e d S a f e Shutdown (SASS) t y p e d e v i c e s . C a l c u l a t i o n s are b e i n g conducted t o i d e n t i f y t h e d e s i g n measures needed t o a s s u r e no b o i l i n g f o r a l o s s of flow w i t h t r i p f a i l u r e . In addition, t h e LSPB decay h e a t removal c a p a b i l i t y i s enhanced by i n c o r p o r a t i n g t h e c a p a b i l i t y f o r n a t u r a l c i r c u l a t i o n i n t h e normal h e a t t r a n s p o r t systems. These d e s i g n f e a t u r e s should i n c r e a s e t h e l i c e n s a b i l i t y and acc e p t a n c e of t h e p l a n t by t h e p u b l i c and t h e u t i l i t i e s . A d d i t i o n a l d e s i g n f e a t u r e s a s s o c i a t e d w i t h s a f e t y and l i c e n s a b i l i t y i n c l u d e t h e u s e of two independent and d i v e r s e r e a c t o r shutdown systems and t h e use of two independent and d i v e r s e , s a f e t y - g r a d e , decay h e a t removal systems. One of t h e s e decay h e a t removal systems c o n s i s t s of two, f o r c e d - c i r c u l a t i o n l o o p s and t h e o t h e r i s a p a s s i v e , n a t u r a l c i r c u l a t i o n loop. Both decay h e a t removal systems use t h e o u t s i d e a i r as t h e i r u l t i m a t e h e a t s i n k and sodium i n t h e r e a c t o r v e s s e l as t h e h e a t source. The LSPB a l s o u t i l i z e s a h e t e r o g e n e o u s c o r e d e s i g n . Because of t h e s e enhanced s a f e t y f e a t u r e s , t h e LSPB b a l a n c e of p l a n t (BOP) d e s i g n h a s been downgraded from s a f e t y g r a d e t o commercial codes t o o b t a i n c o s t r e d u c t i o n s and enhance c o n s t r u c t i b i l i t y . 3.4.3.2

Sodium Advanced F a s t R e a c t o r (SAFR)

T h i s p l a n t , b e i n g d e s i g n e d by t h e team of Rockwell I n t e r n a t i o n a l , B e c h t e l , and Combustion E n g i n e e r i n g , f o r t h e U.S. Department of Energy, c o n s i s t s of one o r more independent power g e n e r a t i n g u n i t s c a l l e d Power Paks, as i l l u s t r a t e d i n F i g u r e 3.5.13-16 The u t i l i z a t i o n of m u l t i p l e u n i t s a t one s i t e p e r m i t s c o s t s a v i n g s through s h a r i n g c e r t a i n f a c i l i t i e s and s e r v i c e s . These s h a r e d f a c i l i t i e s i n c l u d e t h e c o n t r o l b u i l d i n g , t h e p l a n t s e r v i c e b u i l d i n g , t h e n u c l e a r i s l a n d maintenance b u i l d A i n g , and t h e f u e l c y c l e f a c i l i t y i f c o l o c a t e d w i t h t h e power p l a n t . m a j o r g o a l f o r t h e i n i t i a l SAFR d e s i g n e f f o r t w a s t o d e t e r m i n e t h e Power Pak power l e v e l , and t h e r e f o r e s i z e , which i s t h e optimum t r a d e - o f f of c o s t , p a s s i v e s a f e t y , u t i l i t y a c c e p t a n c e , l i c e n s a b i l i t y , and c o n s t r u c t i bility. F a c t o r s which i n f l u e n c e d t h e s e l e c t i o n of t h e 350-MW(e) s i z e i n c l u d e d s h o r t c o n s t r u c t i o n times, low i n v e s t m e n t r i s k , economy of scale, and moderate e n e r g y c o s t s . For t h e b a s i c d e s i g n c o n f i g u r a t i o n of e a c h Power Pak, Rockwell made e f f e c t i v e u s e of t h e i r p r e v i o u s LMR d e s i g n

3-30

ORNL-DWG 86-4051 ETD

F i g . 3.5. Power pak e l e v a t i o n f o r SAFR. Source: Rockwell I n t e r n a t i o n a l , Rocketdyne D i v i s i o n , “SAFR D i s c u s s i o n s a t ORNL, J a n u a r y 11, 1985. “

3-31 e x p e r i e n c e , p a r t i c u l a r l y t h a t a s s o c i a t e d w i t h t h e Large Pool P l a n t (LPP). l7 Advanced LMR technology and enhanced p a s s i v e s a f e t y f e a t u r e s (1) metal f u e l and i n t r o d u c e d i n t o t h e d e s i g n are l i s t e d as f o l l o w s : i t s a s s o c i a t e d r e p r o c e s s i n g i n n o v a t i o n s have been r e t a i n e d as an o p t i o n , ( 2 ) r e d u n d a n t and p a s s i v e decay h e a t removal. systems have been employed, ( 3 ) a r e l a t i v e l y h i g h primary system t e m p e r a t u r e w a s s e l e c t e d w i t h t h e u s e of an advanced material, 9 Cr-1 Mo, f o r t h e e n t i r e i n t e r m e d i a t e l o o p , ( 4 ) a backup, s e l f - a c t u a t e d shutdown system h a s been i n c l u d e d , and ( 5 ) h e t e r o g e n e o u s c o r e d e s i g n s w i t h s e l f - r e g u l a t i n g c h a r a c t e r i s t i c s have been i n c o r p o r a t e d w i t h t h e o b j e c t i v e s of l i m i t i n g t h e p o t e n t i a l e f f e c t of h y p o t h e t i c a l a c c i d e n t s . A s i n d i c a t e d i n T a b l e 3.1, each 350-MW(e) Power Pak c o n s i s t s of a r e a c t o r v e s s e l , primary and i n t e r m e d i a t e h e a t t r a n s p o r t s y s t e m s , a steam g e n e r a t o r system, and a t u r b i n e g e n e r a t o r . Saf e t y - r e l a t e d systems and components are minimized and l o c a l i z e d i n t h e d e s i g n such t h a t n u c l e a r s a f e t y i s decoupled from t h e BOP and I n t e r m e d i a t e Heat T r a n s f e r System (IHTS). The r e a c t o r assembly i s f a c t o r y b u i l t and b a r g e s h i p p a b l e . I t c o n t a i n s t h e primary system and a s p e n t - f u e l s t o r a g e rack. Fuel transf e r i s by a h o i s t mechanism and r o t a t i n g plug which i s p a r t of t h e vess e l head c l o s u r e . I n c l u d e d i n t h e primary system are t h e r e a c t o r , two inducer-type primary pumps, and f o u r i n t e r m e d i a t e h e a t e x c h a n g e r s ( IHXs) I n e a c h of t h e two i n d e p e n d e n t , i n t e r m e d i a t e l o o p s , non-radioa c t i v e sodium i s c i r c u l a t e d through t h e IHXs and a b o o s t e r - t u b e , hockeys t i c k steam g e n e r a t o r o p e r a t i n g i n t h e once-through mode. The superh e a t e d steam from t h e two steam g e n e r a t o r s (one f o r each l o o p ) i s d i r e c t e d t o t h e turbine generator. The r e a c t o r containment b u i l d i n g f o r each Power Pak e n c l o s e s t h e r e a c t o r v e s s e l and t h e in-containment , c o n v e n t i o n a l (A-frame) f u e l h a n d l i n g system. T h i s b u i l d i n g i s a rect a n g u l a r , r e i n f o r c e d concrete s t r u c t u r e with a f l a t roof. Hatches are p r o v i d e d i n t h e roof t o f a c i l i t a t e h a n d l i n g of components, i f n e c e s s a r y , t h u s l i m i t i n g t h e b u i l d i n g s i z e and hence t h e c o n s t r u c t i o n commodities required. The r e a c t o r guard v e s s e l c o n s t i t u t e s p a r t of t h e containment envelope. The non-safety-grade, steam g e n e r a t o r b u i l d i n g f o r e a c h Power

Pak is a conventional building m o u n t e d on the base m a t .

The normal mode of decay h e a t reinoval u s e s n a t u r a l c i r c u l a t i o n of sodium through t h e h e a t t r a n s p o r t systems of t h e Power Pak. I n addit i o n , two i n d e p e n d e n t , n a t u r a l c i r c u l a t i o n , backup systems are provided. The f i r s t i s a d i r e c t r e a c t o r a u x i l i a r y c o o l i n g s y s t e m (DRACS) which t r a n s f e r s h e a t from t h e primary pool t o t h e o u t s i d e a i r u s i n g a sodium-to-air h e a t exchanger. The second i s a p a s s i v e , s a f e t y - r e l a t e d , r e a c t o r a i r c o o l i n g system (RACS) which o p e r a t e s w i t h n a t u r a l c i r c u l a t i o n t o p r o v i d e t h e u l t i m a t e decay h e a t removal c a p a b i l i t y t h r o u g h cooli n g of t h e r e a c t o r guard v e s s e l . The RACS a l s o p r o v i d e s p a s s i v e c o o l i n g of t h e r e a c t o r c a v i t y . The d i v e r s e and redundant shutdown system cons i s t s of b o t h primary and s e c o n d a r y c o n t r o l r o d s as w e l l as a s e l f a c t u a t e d i n h e r e n t shutdown system which responds t o sodium overtemperatures. The s i t e c o n s t r u c t i o n time f o r a Power Pak u n i t , from ground b r e a k i n g t o i n i t i a l power o p e r a t i o n , i s e s t i m a t e d t o be t h i r t y - t h r e e months. The l i c e n s i n g p l a n f o r SAFR stresses s t a n d a r d i z a t i o n and a

3-32 p r e l i c e n s e d Power Pak s o t h a t o n l y s i t e - r e l a t e d l i c e n s i n g c o n s i d e r a t i o n s are r e q u i r e d a f t e r o b t a i n i n g a F i n a l Design Approval. 3.4.3.3

Power R e a c t o r - I n h e r e n t l y

S a f e Module (PRISM)

The PRISM concept of General E l e c t r i c i s b e i n g d e s i g n e d under cont r a c t f o r t h e U.S. Department of Energy.18-21 A s i m p l i f i e d drawing of A major d e s i g n emphasis of t h e t h e concept i s shown i n F i g u r e 3.6. PRISM concept i s i n c o r p o r a t i o n of p a s s i v e s a f e t y t h r o u g h u s e o f : (1) a r e l a t i v e l y low power r e a c t o r c o r e of 133 MW(e), ( 2 ) a p o o l d e s i g n w i t h r e l a t i v e l y low primary sodium t e m p e r a t u r e s , ( 3 ) a s a f e t y - g r a d e p a s s i v e decay h e a t removal system, and ( 4 ) l a r g e n e g a t i v e t e m p e r a t u r e r e a c t i v i t y feedback i n t h e c o r e d e s i g n with t h e i n t e n t of l i m i t i n g p o t e n t i a l c o r e d i s r u p t i v e a c c i d e n t s t o t h e i n i t i a t i n g s t a g e . Another major emphasis of t h e PRISM concept i s l i c e n s i n g by d e m o n s t r a t i o n of p l a n t s a f e t y t h r o u g h t e s t s conducted w i t h a t l e a s t t h e primary system of a p r o t o t y p e r e a c t o r module a t a t e s t f a c i l i t y . T h i s s a f ety-grade r e a c t o r module i s t h e b a s i c power-producing u n i t i n t h e PRISM d e s i g n . The low-pressure, primary system of each module i s a pool-type d e s i g n w i t h t h e r e a c t o r c o r e , f o u r c a r t r i d g e - t y p e , e l e c t r o magnetic primary pumps, and f o u r c a r t r i d g e - t y p e i n t e r m e d i a t e h e a t exchangers a l l contained w i t h i n t h e r e a c t o r v e s s e l . The i n t e r m e d i a t e s y s t e m a s s o c i a t e d w i t h each module c o n s i s t s of a s i n g l e l o o p which t r a n s f e r s h e a t energy from a common h e a d e r , f e d by t h e f o u r i n t e r m e d i a t e h e a t exchangers, t o a s i n g l e steam g e n e r a t o r . Thus, t h e primary l o o p s and t h e s i n g l e , i n t e r m e d i a t e loop a s s o c i a t e d w i t h each r e a c t o r module are independent of t h o s e of o t h e r modules. The common t i e between t h e r e a c t o r modules o c c u r s on t h e t u r b i n e Steam from t h r e e steam g e n e r a t o r s d r i v e s a s i d e of t h e steam drums. s i n g l e turbine. T h e r e f o r e , t h e PRISM d e s i g n , l i k e t h e HTR concept c o n s i d e r e d by NPOVS, has m u l t i p l e r e a c t o r s and t h e i r a s s o c i a t e d h e a t t r a n s p o r t s y s t e m s u p p l y i n g steam t o a s i n g l e t u r b i n e . This power u n i t , o r segment, c o n t a i n i n g t h r e e r e a c t o r s , t h r e e steam g e n e r a t o r s and one t u r b i n e produces about 415-MW(e) of power. A power s t a t i o n , i n t u r n , would c o n s i s t of one o r more of t h e s e segments. The r e f e r e n c e PRISM d e s i g n produces 1245-MW(e) and h a s t h r e e segments f o r a t o t a l of t h r e e t u r b i n e s and n i n e r e a c t o r s . Each segment i s f u n c t i o n a l l y independent of t h e o t h e r s . The homogeneous r e a c t o r c o r e i s f u e l e d w i t h U-Pu oxide. Throughthe-head r e f u e l i n g w i l l occur once each year u s i n g a mobile r e f u e l i n g machine. The r e s i d e n c e t i m e of t h e f u e l i s 4 y e a r s . The r a d i a l blanke t s c o n t a i n i n g U02 c o n t r i b u t e t o a b r e e d i n g r a t i o of about 1.03, des i g n e d t o compensate f o r l o s s e s d u r i n g r e c y c l e . The d i v e r s e and redund a n t c o n t r o l and shutdown system c o n t a i n s s i x primary c o n t r o l rods and two secondary c o n t r o l rods.

3-33

ORNL-DWG 86-4052 ETD

CONTAINMENT VESSEL x 54")

/-(19'D

I. I

' .

6' ".] : *

Fig. 3 . 6 . The below g r a d e modular concept f o r PRISM, October 1984. Source: General E l e c t r i c Company.

3-34 The containment v e s s e l i s 5.79 meters i n d i a m e t e r and 19.5 meters high. The v e s s e l i s shop f a b r i c a t e d and assembled and r a i l s h i p p a b l e . It i s i n s t a l l e d below g r a d e t o f a c i l i t a t e g r o u n d - l e v e l r e f u e l i n g , t o reduce b u i l d i n g c o s t s , and t o p r o v i d e a n a t u r a l b a r r i e r t o missiles. A sodium containment v e s s e l s u r r o u n d s t h e r e a c t o r v e s s e l and i s s i z e d s o t h a t t h e r e a c t o r c o r e w i l l always remain covered by sodium even i f t h e Details of t h e containment/conr e a c t o r v e s s e l should d e v e l o p a l e a k . finement d e s i g n are s t i l l under c o n s i d e r a t i o n . The primary pumps and i n t e r m e d i a t e h e a t exchangers can be removed e a s i l y through t h e t o p head f o r maintenance. The r e a c t o r v e s s e l and containment vessel are i m p o r t a n t components of t h e s a f e t y g r a d e , shutdown h e a t removal system. Normally t h i s r e s i d u a l h e a t would be removed by t h e non-safety g r a d e , secondary h e a t t r a n s p o r t l o o p a s s o c i a t e d w i t h e a c h r e a c t o r module. I f t h i s normal h e a t p a t h i s n o t a v a i l a b l e , t h e s a f e t y g r a d e R e a c t o r Vessel A u x i l i a r y Cooling Syst e m (RVACS) would p r o v i d e t h i s s a f e t y f u n c t i o n . The RVACS i s a p a s s i v e , n a t u r a l c i r c u l a t i o n system t h a t i s always i n o p e r a t i o n . Radiative heat i s t r a n s f e r r e d from t h e r e a c t o r v e s s e l t o t h e containment v e s s e l . This h e a t i s removed t o t h e atmosphere by n a t u r a l c i r c u l a t i o n of o u t s i d e a i r p a s t t h e o u t s i d e s u r f a c e of t h e containment v e s s e l . C a l c u l a t i o n s by GE i n d i c a t e t h a t t h i s system can accommodate decay h e a t removal requirements a f t e r l o s s of normal h e a t removal c a p a b i l i t y c o n c u r r e n t w i t h a r e a c t o r scram. For t h i s case, t h e peak i n t h e primary sodium temperat u r e would be about 600째C and would o c c u r s e v e r a l h o u r s a f t e r t h e s t a r t of t h e e v e n t . An i m p o r t a n t a s p e c t of t h e RVACS system i s t h a t i t s h e a t removal c a p a b i l i t y i n c r e a s e s s u b s t a n t i a l l y w i t h i n c r e a s i n g p r i m a r y sodium t e m p e r a t u r e . The p a s s i v e s a f e t y f e a t u r e s of PRISM are f u r t h e r i n d i c a t e d by i t s r e s p o n s e t o t h e v e r y s e v e r e and u n l i k e l y a c c i d e n t where t h e l o s s of primary c o o l a n t pumping power, t h e l o s s of normal h e a t s i n k , and a f a i l u r e t o scram a l l o c c u r a t t h e same t i m e . The GE a n a l y s i s of t h i s hypot h e t i c a l e v e n t w i t h no o p e r a t o r i n t e r v e n t i o n p r e d i c t e d t h a t , a f t e r some i n i t i a l o s c i l l a t i o n s i n c o r e r e a c t i v i t y and t e m p e r a t u r e , a n e q u i l i b r i u m s i t u a t i o n would be reached w i t h i n about t e n h o u r s w i t h o u t e x c e e d i n g allowable temperatures. A t t h i s equilibrium state, t h e heat generation r a t e of t h e c r i t i c a l c o r e would be matched by t h e h e a t r e j e c t i o n r a t e of t h e RVACS system w i t h a system t e m p e r a t u r e of about 630째C. F a c t o r y f a b r i c a t i o n and assembly, s t a n d a r d i z a t i o n , and a r e d u c t i o n i n systems r e q u i r e d t o be s a f e t y g r a d e have been s t r e s s e d i n t h e PRISM d e s i g n as a m a n s of o f f s e t t i n g a p e r c e i v e d diseconomy of scale f o r small u n i t s . Advantages p r o j e c t e d f o r t h i s c o n s t r u c t i o n t e c h n i q u e i n c l u d e more e f f i c i e n t u s e of s i t e l a b o r , a much s h o r t e r c o n s t r u c t i o n t i m e of t h r e e y e a r s from s t a r t of c o n s t r u c t i o n t o f u l l power o p e r a t i o n , " l e a r n i n g curve" b e n e f i t s due t o r e p l i c a t i o n , and a c l o s e r p o t e n t i a l Since match of a u t i l i t y ' s power p r o d u c t i o n c a p a b i l i t i e s t o i t s l o a d . t h e r e a c t o r module i s t h e o n l y n u c l e a r q u a l i f i e d component, t h e b a l a n c e of p l a n t can be c o n s t r u c t e d e c o n o m i c a l l y t o h i g h q u a l i t y i n d u s t r i a l standards.

3-35

The PRISM l i c e n s i n g p l a n c a l l s f o r p r e l i c e n s i n g of a p r o t o t y p i c r e a c t o r module s o t h a t o n l y s i t e s p e c i f i c i s s u e s need be a d d r e s s e d f o r licensing a plant. T h i s p r e l i c e n s i n g would be accomplished through a d e s i g n and s a f e t y t e s t program d u r i n g which t h e b a s i c s a f e t y and economic claims f o r t h e concept would be demonstrated by p r o t o t y p i c , f u l l scale t e s t s .

3.4.4

Advantages and Disadvantages of t h e LMR Concepts w i t h Regard t o t h e NPOVS C r i t e r i a and E s s e n t i a l Characteristics

3.4.4.1

G e n e r a l Overviews

C o m m e r c i a l i z a t i o n and m a r k e t i n g of a n LMR i n t h e a n t i c i p a t e d market between now and around t h e y e a r 2010 may be d i f f i c u l t t o accomplish. Not only do LMRs have t h e same n e g a t i v e market f a c t o r s as o t h e r conc e p t s , i n c l u d i n g an u n c e r t a i n t y i n t h e need f o r power, l i c e n s i n g c h a l l e n g e s , and f i n a n c i a l u n c e r t a i n t i e s , b u t LMRs must a l s o overcome addit i o n a l c o n c e r n s such as h i g h e r c a p i t a l c o s t s a s s o c i a t e d w i t h t r a d i t i o n a l d e s i g n s , t h e i r p e r c e i v e d r o l e only as b r e e d e r s , a l a c k of u t i l i t y e x p e r i e n c e w i t h LMRs, and u n c e r t a i n t i e s a s s o c i a t e d w i t h an a d e q u a t e and c o s t competitive f u e l cycle. I n f a c t , one could a r g u e t h a t LMRs w i l l p e n e t r a t e t h i s market o n l y i f t h e y have a unique and v e r y i m p o r t a n t a d v a n t a g e o v e r o t h e r power g e n e r a t i n g c o n c e p t s . Such an a d v a n t a g e inay a r i s e from t h e i n n o v a t i v e LMR d e s i g n s e v a l u a t e d here. T h e i r s t r o n g emphasis on c o s t r e d u c t i o n , p a s s i v e s a f e t y , r a p i d c o n s t r u c t i o n , l i c e n s a b i l i t y , and low economic r i s k are c e r t a i n l y a p p r o p r i a t e t o meet t h e c h a l l e n g e s of f u t u r e markets. In t h e discussion which f o l l o w s , t h e a d v a n t a g e s and d i s a d v a n t a g e s , o r c h a l l e n g e s , o u t l i n e d above w i l l be d i s c u s s e d i n t h e same o r d e r as t h e NPOVS c r i t e r i a , essent i a l c h a r a c t e r i s t i c s , and d e s i r a b l e c h a r a c t e r i s t i c s p r e s e n t e d i n S e c t i o n 2.2.1. Many of t h e s e comments a p p l y t o a l l of t h e LMR c o n c e p t s and t h e y w i l l be p r e s e n t e d f i r s t . These w i l l be f o l l o w e d by c o m m e n t s s p e c i f i c t o a p a r t i c u l a r concept. Advantages of t h e LMR Concepts

3.4.4.2 1

P u b l i c Risk: A s i g n i f i c a n t f e a t u r e of LMRs i s t h e p a s s i v e s a f e t y which may be i n c o r p o r a t e d i n t o t h e i r d e s i g n s . 7 Among t h e p a s s i v e f e a t u r e s i s t h e tendency f o r sodium t o p r o v i d e n a t u r a l c o n v e c t i o n c o o l i n g , t h e h i g h t h e r m a l c o n d u c t i v i t y of sodium, t h e l a r g e h e a t c a p a c i t y of t h e r e a c t o r system (which a f f o r d s l o n g g r a c e p e r i o d s f o r problem d i a g n o s i s and c o r r e c t i v e a c t i o n ) , low-pressure d e s i g n , and o p e r a t i n g t e m p e r a t u r e s f a r below t h e b o i l i n g p o i n t of sodium. The u s e f u l n e s s and e f f e c t i v e n e s s of t h e s e f e a t u r e s were s u c c e s s f u l l y d e m o n s t r a t e d i n tests a t s e v e r a l p l a n t s i n c l u d i n g t h e P r o t o t y p e F a s t React o r (PFR), Phenix, and t h e FFTF. They are u t i l i z e d i n a l l t h r e e of t h e d e s i g n s c o n s i d e r e d h e r e . Because of p a s s i v e

3-36 s a f e t y f e a t u r e s , t h e s e d e s i g n s r e q u i r e fewer e n g i n e e r e d ( a c t i v e ) s a f e t y systems and less emergency power t h a n convent i o n a l LWRs. One c a u t i o n i s t h a t , s i n c e t h e s e d e s i g n s r e l y on o u t s i d e a i r as t h e f i n a l h e a t t r a n s f e r mediumlsink f o r d e c a y h e a t removal, t h e y might be s u s c e p t i b l e t o common c a u s e e x t e r n a l d e g r a d a t i o n e v e n t s , such as f i r e s o r d u s t s t o r m s . 2 2 The t h r e e d e s i g n s c o n s i d e r e d h e r e i n c o r p o r a t e a r e a c t o r shutdown system similar t o t h e CRBRP c o n c e p t . They may enhance t h e p a s s i v e s a f e t y of t h e i r s y s t e m w i t h r e s p e c t t o Hypot h e t i c a l Core D i s r u p t i v e A c c i d e n t s (HCDAS) t h r o u g h a p a s s i v e c o n t r o l - r o d release mechanism which w i l l be a c t i v a t e d by h i g h sodium t e m p e r a t u r e . T h i s f e a t u r e may t e r m i n a t e any over-heati n g e v e n t b e f o r e sodium b o i l i n g o c c u r s . The d e s i g n s a l s o l i m i t t h e t o t a l amount and r a t e of r e a c t i v i t y i n s e r t i o n p o s s i b l e i n t h e e v e n t of a c o n t r o l - r o d w i t h d r a w a l a c c i d e n t . In addition, t h e a s s u r a n c e of decay h e a t removal c a p a b i l i t i e s i s p r o v i d e d by b o t h a c t i v e and p a s s i v e systems which i n c o r p o r a t e s i g n i f i c a n t redundancy and d i v e r s i t y . F i n a l l y , f o r t h e PRISM and SAFR d e s i g n s i n p a r t i c u l a r , t h e c o r e and c o n t r o l d r i v e l i n e s are b e i n g d e s i g n e d so t h a t many HCDA i n i t i a t i n g e v e n t s w i l l be terminated

and r e s u l t i n g initiates.

feedback

thermal

responses

expansion

from

temperature

before

core

increases

degradation

I n our judgment, ZMR d e s i g n s can meet and probably s i g n i f i c a n t l y exceed t h e g o a l s of NPOVS C r i t e r i o n 1. For examp l e , t h e PRA s t u d y completed f o r t h e CRBRP c a l c u l a t e d a c o r e damage f r e q u e n c y f o r an HCDA t o be 3.6 x 10-5/year, w i t h seismic e v e n t s b e i n g t h e major i n i t i a t o r . 2 3 The f r e q u e n c y f o r Another i n t e r n a l i n i t i a t o r s w a s about a f a c t o r of t e n less. i n d e p e n d e n t s t u d y f o r t h e SNR-300 p l a n t i n Germany concluded t h a t , "both t h e f r e q u e n c y of major a c c i d e n t s and t h e e x t e n t of damage a s s o c i a t e d w i t h such a c c i d e n t s are smaller t h a n t h o s e e s t i m a t e d i n t h e German Risk Study f o r t h e PWR-1300."24 These d e s i g n s a c h i e v e low HCDA p r o b a b i l i t i e s t o a g r e a t e x t e n t because of t h e r e l i a b i l i t y of a c t i v e s a f e t y s y s t e m s , p a r t i c u l a r l y t h e d i v e r s e and redundant r e a c t o r shutdown systems. C r e d i t f o r i n h e r e n t o r p a s s i v e r e s p o n s e s of t h e c o r e which c o u l d r e s u l t i n e a r l y t e r m i n a t i o n of t h e e v e n t are i n c o r p o r a t e d i n t o t h e c a l c u l a t i o n s i n a c o n s e r v a t i v e manner. 2.

I n v e s t m e n t Risk: I n o u r judgment, t h e LMR d e s i g n s can meet and p r o b a b l y s i g n i f i c a n t l y exceed t h e g o a l of NPOVS c r i t e r i o n 2. The emphasis on s i m p l i c i t y of d e s i g n , t h e u s e of fewer complex s a f e t y s y s t e m s , and t h e i n c o r p o r a t i o n of p a s s i v e d e s i g n f e a t u r e s , d i s c u s s e d under c r i t e r i o n 1 , would a l l c o n t r i b u t e t o low i n v e s t m e n t r i s k . In a d d i t i o n , e x t e n s i v e r e l i a b i l i t y s t u d i e s and PRA e v o l u t i o n s are planned f o r e a c h design.

3-37

Economic C o m p e t i t i v e n e s s : The c a p a b i l i t y of b r e e d i n g s i g n i f i c a n t l y more f u e l t h a n i s consumed i n producing power i s a m a j o r long-term advantage of LMRs. This b r e e d i n g c a p a b i l i t y , coupled w i t h a complete f u e l c y c l e , would e n a b l e LMRs t o ext r a c t between 60 and 80 t i m e s t h e energy from a g i v e n q u a n t i t y of n a t u r a l uranium t h a n can be done u s i n g n ~ n - b r e e d e r s . ~ I n a d d i t i o n , LMR o p e r a t i n g c o s t s need n o t be as s e n s i t i v e t o f u e l c o s t s as non-breeders. The LMR d e s i g n s can o f f e r b r e e d i n g as a d e s i g n o p t i o n t o be implemented by a r e l a t i v e l y e a s y and i n e x p e n s i v e c o r e m o d i f i c a t i o n when i t becomes e c o n o m i c a l l y a t t r a c t i v e t o do so. Comparative e v a l u a t i o n s r e p o r t e d i n Chapter 3 , Volume 111, of t h i s r e p o r t i n d i c a t e a p o t e n t i a l c o m p e t i t i v e n e s s w i t h b o t h t h e b e s t LWR e x p e r i e n c e and w i t h coal-f i r e d p l a n t s . The LSPB concept h a s p e r c e i v e d economy-of -scale advant a g e s and has i n c o r p o r a t e d s i g n i f i c a n t c o s t r e d u c t i o n f e a t u r e s and a s h o r t c o n s t r u c t i o n s c h e d u l e i n t o t h e d e s i g n . The a b i l i t y t o add p l a n t s i n smaller power i n c r e m e n t s , t h e r e b y b e t t e r matching u t i l i t y n e e d s , i s a p o t e n t i a l a d v a n t a g e of t h e PRISM and SAFR d e s i g n s . T h e i r lower c a p i t a l r i s k a c h i e v e d by modular c o n s t r u c t i o n and v e r y s h o r t c o n s t r u c t i o n t i m e s i s a l s o attractive. However, i t i s n o t c l e a r how c o s t s f o r t h e f a c t o r i e s t o b u i l d t h e s e modules w i l l be a s s e s s e d and c o s t s f o r This may i n c r e a s e t h e t h e f u e l c y c l e w i l l be i n c o r p o r a t e d . c o s t of t h e f i r s t s e v e r a l p l a n t s , and i t may be d i f f i c u l t t o j u s t i f y t h e h i g h i n i t i a l c o s t s f o r f a c t o r y a u t o m a t i o n which would improve m a n u f a c t u r i n g e f f i c i e n c y . SAFR p l a n s a r e t o u s e e x i s t i n g f a c i l i t i e s with increased automation f o r v e s s e l assembly p r o d u c t i o n up t o a few u n i t s p e r year.

P r o b a b i l i t y of Cost/ Schedule Overruns: A l l three concepts have s t r e s s e d c o n s t r u c t i b i l i t y and s i m p l i c i t y , and a complete design before construction. They u t i l i z e d modular c o n s t r u c t i o n of major components i n a f a c t o r y and shipment t o t h e s i t e , and non-safety g r a d e c o n s t r u c t i o n a t t h e s i t e f o r t h e BOP. These a p p r o a c h e s should minimize d e l a y s and c o s t overr u n s a t t r i b u t a b l e t o q u a l i t y a s s u r a n c e problems and l a r g e conThere i s a l a c k of U.S. i n d u s t r y e x p e r i e n c e s t r u c t i o n crews. i n LMR c o n s t r u c t i o n . However, r e c e n t documentation of cons t r u c t i o n e x p e r i e n c e i n d i c a t e s t h a t c o n s t r u c t i o n problems are more a f u n c t i o n of t h e management and c o n s t r u c t i o n team and t h e i r i n t e r a c t i o n w i t h t h e NRC t h a n t h e r e a c t o r type.25 The concept of l e a r n i n g by e x p e r i e n c e s h o u l d a p p l y t o SAFR and PRISM i f a d d i t i o n a l modules and Power Paks can be b u i l t by t h e same team w i t h o u t d e l a y a f t e r c o m p l e t i o n of t h e f i r s t p l a n t segment. T h i s can be done w h i l e t h e f i r s t segment i s producing power, but care must be t a k e n t o a v o i d j e o p a r d y t o t h e o p e r a t i n g u n i t by t h e c o n s t r u c t i o n a c t i v i t i e s where c l o s e p r o x i m i t y i s r e q u i r e d such as i n the c o n t r o l b u i l d i n g .

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Licensability. Assurance of l i c e n s a b i l i t y b e f o r e c o n s t r u c t i o n i s emphasized by t h e s e LMR c o m m e r c i a l i z a t i o n p l a n s . Each stresses e a r l y a p p r o v a l by NRC of a s t a n d a r d p l a n t design. Thus, o n l y s i t e - s p e c i f i c NRC c o n c e r n s would need t o be a d d r e s s e d f o r l i c e n s i n g of subsequent p l a n t s . The l i c e n s a b i l i t y of t h e LSPB should be r e l a t i v e l y h i g h because t h e d e s i g n b a s i s a c c i d e n t a n a l y s i s and many key s a f e t y d e s i g n f e a t u r e s are based on t h e CRBRP l i c e n s i n g e x p e r i e n c e . The f i r s t c h o i c e f o r PRISM l i c e n s i n g , and an a l t e r n a t i v e f o r SAFR, c a l l s f o r d e m o n s t r a t i o n of t h e p l a n t ' s p a s s i v e prot e c t i o n a g a i n s t t r a d i t i o n a l HCDA i n i t i a t o r s through t e s t s of a p r o t o t y p i c r e a c t o r module. This concept of l i c e n s i n g by t e s t has a t t r a c t i v e features. Chief among t h e s e a r e a p o s s i b l e red u c t i o n of a n a l y s e s , v a l i d a t i o n of computer c o d e s , and demons t r a t i o n of s a f e t y claims t o t h e p u b l i c , p o t e n t i a l i n v e s t o r s , and t h e NRC. Some precedence has been e s t a b l i s h e d f o r such tests t h r o u g h t h e e x t e n s i v e program a t t h e Southwest E x p e r i m e n t a l F a s t Oxide Reactor (SEFOR) which d e m o n s t r a t e d t h e e f f e c t of the Doppler c o e f f i c i e n t on power e x c u r s i o n , l g and t h e r e c e n t t e s t s a t Raposdiel6 and EBR-I1 where loss-of-flow HCDAs were i n i t i a t e d and s u b s e q u e n t l y t e r m i n a t e d by p a s s i v e feedback of t h e core. The SAFR d e s i g n e r s i n d i c a t e t h a t a p o s s i b l y more c o s t e f f e c t i v e approach i n v o l v e s r e s o l v i n g t h e main l i c e n s i n g i s s u e s by e x t r a p o l a t i o n of t e s t r e s u l t s from FFTF and EBR-11. Then a p l a n t i n s t a l l e d on a u t i l i t y g r i d would be t h e v e h i c l e f o r obt a i n i n g a s t a n d a r d p l a n t FDA w i t h rulemaking t o a p p l y t o subs e q u e n t p l a n t s of t h e same design.

Demonstration of Readiness: Europe and J a p a n , which have less abundant n a t u r a l s u p p l i e s of f i s s i l e material, p e r c e i v e a need f o r b r e e d e r s sooner t h a n t h e United S t a t e s . For t h i s r e a s o n t h e s e c o u n t r i e s a r e p u r s u i n g a v i g o r o u s program of demonstrat i o n and c o m m e r c i a l i z a t i o n of t h e e n t i r e LMFBR f u e l c y c l e . One can estimate from p r o j e c t s now i n p l a c e t h a t 50 p l a n t - y e a r s of o p e r a t i o n c o u l d be compiled by LMR d e m o n s t r a t i o n p l a n t s by t h e y e a r 2000.* From p a s t e x p e r i e n c e , a c c e p t a b l e performance i s e x p e c t e d from t h e s e p l a n t s . For example, s i n c e 1973 t h e French, 250-MW(e) Phenix p r o t o t y p e p l a n t h a s o p e r a t e d w i t h a n o v e r a l l c a p a c i t y f a c t o r of 60%.* T h i s e x p e r i e n c e base will be r e l e v a n t t o t h e requirement f o r a s u c c e s s f u l d e m o n s t r a t i o n plant. A s t r i c t i n t e r p r e t a t i o n of C r i t e r i o n 6 r e q u i r e s t h a t d e m o n s t r a t i o n p l a n t s f o r t h e s p e c i f i c LMR p l a n t c o n c e p t s be b u i l t and o p e r a t e d i n t h e United S t a t e s b e f o r e a u t i l i t y d e c i s i o n t o buy i s made. To accomplish t h i s t a s k w i t h i n t h e NPOVS t i m e frame i s a s i g n i f i c a n t c h a l l e n g e . Nevertheless,

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o u r judgment from e v a l u a t i o n s of t h e m a r k e t i n g and commerciali z a t i o n p l a n s f o r LSPB, SAFR, and PRISM i s t h a t implementation of any of t h e s e p l a n s w i t h a d e d i c a t e d e f f o r t could r e s u l t i n satisfying this criterion. Owner Competence: There are many s i m i l a r i t i e s i n t h e opera t i o n of LMRs and LWRs, p a r t i c u l a r l y w i t h r e g a r d t o r e a c t o r c o n t r o l and BOP f u n c t i o n i n g . Thus a s i g n i f i c a n t f r a c t i o n of LWR o p e r a t o r t r a i n i n g and e x p e r i e n c e would be r e l e v a n t t o LMRs. I n a d d i t i o n , worldwide e x p e r i e n c e i n d i c a t e s t h a t LMRs are r e l a t i v e l y e a s y t o o p e r a t e and m a i n t a i n . P e r s o n n e l spec i f i c a l l y t r a i n e d i n t h e o p e r a t i o n of sodium systems w i t h i n t h e United S t a t e s are a t n a t i o n a l l a b o r a t o r i e s , i n d u s t r i a l t e s t f a c i l i t i e s , and a t t h e U.S. o p e r a t i n g LMRs, EBR-I1 and FFTF e

Essential Characteristics: The IMR concept d e s i g n e r s have s t r e s s e d shop f a b r i c a t i o n , minimizing n u c l e a r g r a d e compon e n t s , s t a n d a r d i z a t i o n , l o n g p l a n t l i f e t i m e , ease of c o n s t r u c t i o n , and p a s s i v e s a f e t y f e a t u r e s . The PRISM and SAFR d e s i g n s o f f e r a v a r i e t y of p l a n t s i z e s t o match l o a d growth and, as e x p l a i n e d i n Chapter 3 of Volume I11 d e a l i n g w i t h economics, some a v a i l a b i l i t y advantages may r e s u l t from smaller, m u l t i p l e reactor cores.

Desirable Characteristics: R e l a t i v e l y high t h e r m a l e f f i c i e n cies ( - 4 0 % ) have been achieved w i t h LMR d e s i g n s and v e r y low r a d i a t i o n e x p o s u r e s t o workers (on t h e o r d e r of a few man-rems p e r y e a r ) have been e x p e r i e n c e d i n d e m o n s t r a t i o n p l a n t s . Enhanced d i v e r s i o n and p r o l i f e r a t i o n r e s i s t a n c e i s p o s s i b l e w i t h Fuel o n - s i t e f u e l r e c y c l e and with t h e metal f u e l o p t i o n . e l e m e n t s can be r e t a i n e d i n t h e c o r e f o r s e v e r a l y e a r s , t h e r e by y i e l d i n g burnup v a l u e s >lo0 MWd/kg. Disadvantages of t h e LMR Concepts

3.4.4.3 1.

P u b l i c Risk: Unlike LWRs which are d e s i g n e d t o maximize k e f f , an LMR under normal o p e r a t i n g c o n d i t i o n s i s n o t i n i t s most r e a c t i v e configuration. Thus, l o s s of sodium c o o l a n t from t h e c o r e o r c o r e compaction could r e s u l t i n a r e a c t i v i t y i n c r e a s e . The d e s i g n s c o n s i d e r e d h e r e p r o v i d e p r o t e c t i o n a g a i n s t l o s s of sodium i n v e n t o r y due t o l e a k s and have s u b s t a n t i a l m i t i g a t i n g f e a t u r e s - which are amenable t o d e m o n s t r a t i o n f o r accommod a t i n g h y p o t h e t i c a l a c c i d e n t s even beyond t h e d e s i g n b a s i s . N e v e r t h e l e s s , t h e way i n which t r a d i t i o n a l l i c e n s i n g concerns a s s o c i a t e d w i t h h y p o t h e t i c a l a c c i d e n t s are a d d r e s s e d w i l l need t o be f u l l y developed.

Investment Risk: I n a d d i t i o n t o t h e comments made under p u b l i c r i s k , some concern s t i l l e x i s t s about t h e performance and r e l i a b i l i t y of LMR steam g e n e r a t o r s . Data which could v e r i f y t h e performance of c u r r e n t d e s i g n s s h o u l d be a v a i l a b l e

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w i t h i n t h e NPOVS t i m e p e r i o d from component t e s t i n g programs and f o r e i g n p l a n t e x p e r i e n c e .

Economic C o m p e t i t i v e n e s s : E v a l u a t i o n s of p r o t o t y p e LMR d e s i g n s and f o r e i g n c o n s t r u c t i o n e x p e r i e n c e i n d i c a t e s t h a t t h e c a p i t a l c o s t s f o r LMR commercial p l a n t s , based on t r a d i t i o n a l d e s i g n s of t h e 1980s, could be s u b s t a n t i a l l y h i g h e r t h a n This higher c a p i t a l cost, r e s u l t i n g i n p a r t p r e s e n t LWRs. from t h e need f o r a n i n t e r m e d i a t e l o o p , could be compensated by lower f u e l c o s t s and h i g h e r e f f i c i e n c i e s f o r LMRs. Higher e f f i c i e n c i e s f o r LMRs have indeed been r e a l i z e d ; t h e Phenix p l a n t , f o r example, h a s a g r o s s e f f i c i e n c y of 4 4 % . 1 8 But, as i n d i c a t e d below, i t i s n o t clear t h a t t h e p o t e n t i a l f u e l - c y c l e c o s t advantage f o r LMRs w i l l be r e a l i z e d w i t h i n t h e NPOVS t i m e constraints. Longer c o r e l i f e t i m e s are b e i n g s t u d i e d i n f u t u r e plans. I n summary, c o s t c o m p e t i t i v e n e s s can n o t be claimed f o r o p e r a t i n g LMR d e m o n s t r a t i o n p l a n t s and, assuming no d r a m a t i c changes i n f u e l c o s t s w i t h i n t h e NPOVS t i m e frame, c o m p e t i t i v e n e s s of commercial LMR p l a n t s can b e s t be a c h i e v e d by s i g n i f i c a n t r e d u c t i o n s i n c a p i t a l c o s t s .

P r o b a b i l i t y of C o s t / S c h e d u l e Overruns: No s p e c i f i c d i s a d v a n t a g e i d e n t i f i e d e x c e p t t h a t t h e s e are new d e s i g n c o n c e p t s w i t h no d i r e c t base of e x p e r i e n c e .

Licensability: The w r i t s of l i c e n s i n g by p r o t o t y p i c t e s t s have been d i s c u s s e d p r e v i o u s l y . There a r e , however, some l i m i t a t i o n s of t h i s approach. Not a l l s a f e t y claims o r h y p o t h e t i c a l a c c i d e n t sequences can be d e m o n s t r a t e d , and a n a l y s i s of a c c i d e n t sequences may s t i l l be r e q u i r e d . In addition, t h i s could be an e x p e n s i v e t e s t program even i f t h e module c a n s u b s e q u e n t l y be used commercially s i n c e t h e t e s t program c o u l d l a s t s e v e r a l y e a r s and a n a l y s e s of pre- and p o s t - t e s t r e s u l t s On t h e o t h e r hand, t h e PRISM c o u l d be a s i g n i f i c a n t e f f o r t . d e s i g n e r s b e l i e v e t h i s d e m o n s t r a t i o n t o be r e l a t i v e l y l e s s e x p e n s i v e f o r a small r e a c t o r when compared t o t h e p o t e n t i a l c o s t s and r i s k s a s s o c i a t e d w i t h l i c e n s i n g a l a r g e r e a c t o r . An a l t e r n a t i v e would be t o u s e t h e d e m o n s t r a t i o n f a c i l i t y not o n l y as a t e s t of t h e PRISM a n d / o r SAFR d e s i g n s but a l s o a s an advanced r e s e a r c h and development f a c i l i t y f o r g e n e r a l LMR p a s s i v e s a f e t y f e a t u r e s t e s t s . It c o u l d d e m o n s t r a t e react i v i t y feedback e f f e c t s as w e l l as p r o v i d e d a t a f o r code verification. Perhaps a l t e r n a t e c o r e s , metal a n d / o r c a r b i d e , c o u l d be d e s i g n e d f o r t h e same f a c i l i t y . P a s s i v e shutdown systems and decay h e a t removal systems could be d e m o n s t r a t e d as w e l l . However, i t s u t i l i t y f o r some of t h e s e p u r p o s e s s h o u l d be e v a l u a t e d w i t h r e s p e c t t o t h e FFTF and EBR-I1 capabilities.

I n a d d i t i o n t o l i c e n s i n g by t e s t , o t h e r LMR l i c e n s i n g i s s u e s would s t i l l need t o be c o n s i d e r e d f o r t h e s t a n d a r d p l a n t designs. Prominent among t h e s e i s s u e s w i l l be t h e

3-41 s i t e - s u i t a b i l i t y s o u r c e t e r m , s a f e t y f u n c t i o n s and d e s i g n d e c i s i o n s a s s o c i a t e d w i t h c o n t a i n m e n t , p a s s i v e f e a t u r e s which accommodate HCDA c o n c e r n s , and t h e need f o r redundancy and/or d i v e r s i t y w i t h i n and i n a d d i t i o n t o s a f e t y systems which a r e passive. Although u s e f u l e x p e r i e n c e w a s g a i n e d through FFTF and CRBRP i n t e r a c t i o n s and l i c e n s i n g a c t i v i t i e s w i t h t h e NRC, l i c e n s i n g r u l e s , g u i d e l i n e s , and p r o c e d u r e s are n o t as w e l l e s t a b l i s h e d f o r LMRs as f o r LWRs. However, p r e l i m i n a r y d i s c u s s i o n s have been i n i t i a t e d w i t h NRC f o r t h e ZMR c o n c e p t s .

Demonstration of R e a d i n e s s : Providing funding f o r d e m o n s t r a t i o n p l a n t w i l l be a s i g n i f i c a n t c h a l l e n g e .

Owner Competence: Even though a l a r g e number of u t i l i t i e s p a r t i c i p a t e d t o v a r y i n g d e g r e e s i n t h e CRBRP, e x p e r i e n c e i n LMR o p e r a t i o n does n o t c u r r e n t l y e x i s t w i t h i n t h e U.S. u t i l i t y o r g a n i z a t i o n s , and t h e FFTF and EBR I1 a f f o r d o n l y p a r t of t h e requirement.

LMR

P e r h a p s a more p e r t i n e n t q u e s t i o n i s whether t h e owner/ o p e r a t o r c o u l d be convinced t o p u r c h a s e a new r e a c t o r c o n c e p t This l a t t e r need i s f o r which u t i l i t y e x p e r i e n c e i s l i m i t e d . p e r h a p s most c l e a r l y e v i d e n t when one c o n s i d e r s a s p e c t s of t h e LMR f u e l c y c l e . In s h o r t , each f u e l c y c l e o p t i o n a p p e a r s t o have some s i g n i f i c a n t d i f f i c u l t i e s . To p r o v i d e unique LMR a d v a n t a g e s a s s o c i a t e d w i t h b r e e d i n g , such as r e l a t i v e freedom from c o n c e r n s about a r e l i a b l e f u e l s u p p l y , a complete f u e l c y c l e s h o u l d be u t i l i z e d . T h i s means t h a t proven and r e l i a b l e o n - s i t e o r o f f - s i t e r e p r o c e s s i n g , r e f a b r i c a t i o n , and waste h a n d l i n g of s u i t a b l e scale must be a v a i l a b l e t o t h e m e r / operator at a reasonable cost. The b a s i c t e c h n o l o g y r e q u i r e d f o r LMR f u e l c y c l e s h a s been developed i n t h e United S t a t e s and d e m o n s t r a t e d o v e r s e a s , and t h e f i r s t few LMRs c o u l d b e s u p p o r t e d by small-scale development f a c i l i t i e s . However, i f one assumes t h a t t h i s c a p a b i l i t y w i l l be provided o n - s i t e , t h e n u n c e r t a i n t i e s a s s o c i a t e d w i t h a v a i l a b l e t r a i n e d personn e l , c o s t , s a f e g u a r d s , r e l i a b i l i t y , l i c e n s a b i l i t y , and p u b l i c and u t i l i t y a c c e p t a n c e are e n v i s i o n e d . (See a l s o Appendix E). It i s n o t d i f f i c u l t t o c o n c l u d e , f o r example, t h a t c o s t s s a v i n g s o r o t h e r i n c e n t i v e s must be s i g n i f i c a n t and proven by e x p e r i e n c e b e f o r e a u t i l i t y would choose t o p u r c h a s e and o p e r a t e a r e p r o c e s s i n g p l a n t . T e c h n i c a l and o r g a n i z a t i o n a l o p t i o n s making t h i s concept more a t t r a c t i v e i n c l u d e a l e s s complex f u e l c y c l e , t h e IFR c o n c e p t f o r example,26 o r t h e o p t i o n t h a t some o t h e r i n s t i t u t i o n ( n o t t h e u t i l i t y ) o p e r a t e a l l f a c i l i t i e s e x c e p t ( o r i n c l u d i n g ) t h e power s t a t i o n . These, and perhaps o t h e r o p t i o n s , c o u l d improve t h e v i a b i l i t y ,

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b u t a c c e p t a n c e of t h i s concept by a u t i l i t y and i t s implement a t i o n and d e m o n s t r a t i o n i n t h e NPOVS t i m e frame seems unlikely. I f , on t h e o t h e r hand, one assumes t h a t o f f - s i t e , cent r a l , r e p r o c e s s i n g f a c i l i t i e s would be used t o complete t h e f u e l c y c l e , i t i s d i f f i c u l t t o e n v i s i o n t h e economic need f o r commercial f a c i l i t i e s of t h i s t y p e much b e f o r e t h e middle of Thus, o f f - s i t e r e p r o c e s s i n g may n o t be t h e 2 1 s t century. a v a i l a b l e i n t h e United States w i t h i n t h e NPOVS t i m e frame. S t i l l another option f o r closing t h e f u e l cycle is t o r e l y on o t h e r c o u n t r i e s t o p r o v i d e t h i s s e r v i c e . D i f f i c u l t i e s a s s o c i a t e d w i t h t h i s o p t i o n i n c l u d e problems a s s o c i a t e d w i t h Pu shipments between c o u n t r i e s , a d v e r s e b a l a n c e of payments, and t h e assumption t h a t such a commercial i n d u s t r y w i l l i n f a c t be a v a i l a b l e t o t h e United S t a t e s .

I f c o u n t i n g on a commercial f u e l r e p r o c e s s i n g i n d u s t r y i s imprudent, a n o t h e r o p t i o n i s t o c o n s i d e r a once-through c y c l e , i n c l u d i n g t h e p o s s i b i l i t y of s p e n t f u e l s t o r a g e u n t i l commercial reprocessing/refabrication facilities are available. D i f f i c u l t i e s a s s o c i a t e d w i t h t h i s c h o i c e are economic ( t r a d i t i o n a l LMRs w i t h once-through f u e l c y c l e s would have f u e l c o s t s about twice t h o s e w i t h Plutonium r e c y c l e 2 7 ) and i n s t i t u tional. Once-through c y c l e s may need t o u s e 235U e n r i c h e d t o 20 t o 30% which are l e v e l s beyond p r e s e n t p r o d u c t i o n f o r commercial use. The once-through o p t i o n c o u l d l i k e l y be enhanced by t h e i n c o r p o r a t i o n of low-power d e n s i t y , heterogeneous, l o n g - l i v e d (10 y e a r s o r more) c o r e d e s i g n s .

E s s e n t i a l C h a r a c t e r i s t i c s : Maintenance r e q u i r e m e n t s and opera t i n g s t a f f s f o r PRISM, and t o a lesser e x t e n t SAFR, may exSecurity s t a f f ceed t h o s e f o r p l a n t s w i t h a s i n g l e r e a c t o r . r e q u i r e m e n t s f o r PRISM can be small because of underground l o c a t i o n and i n a c c e s s i b i l i t y of key s a f e t y f e a t u r e s d u r i n g operation. On t h e o t h e r h a n d , r e g u l a r l y s c h e d u l e d r e f u e l l i n g and maintenance reduces t h e need f o r e x t r a manpower peaks a t annual r e f u e l l i n g i n a monolithic plant. I n a d d i t i o n , d e s i g n of t h e c o n t r o l system f o r PRISM must accommodate m u l t i p l e r e a c t o r c o r e s p r o v i d i n g t h e main s o u r c e of energy t o a s i n g l e t u r bine. Licensing requirements, p a r t i c u l a r l y those associated w i t h t h e o p t i o n of r e p r o c e s s i n g and r e f a b r i c a t i o n of f u e l ons i t e , are n o t completely d e f i n e d . If t h e o v e r a l l nuclear ind u s t r y , i n c l u d i n g government s u p p o r t , c o n t i n u e s t o d e c l i n e , t h e a v a i l a b i l i t y of q u a l i f i e d vendors may be i n q u e s t i o n .

Desirable Characteristics: On-line r e f u e l i n g , though c o n s i d e r e d , has n o t been i n c o r p o r a t e d i n t o any d e s i g n s . The PRISM p l a n t , however, does have t h e c a p a b i l i t y t o g e n e r a t e e l e c t r i c power c o n t i n u o u s l y w h i l e a s i n g l e module i s being r e f u e l e d . Completion of t h e f u e l c y c l e , i m p o r t a n t f o r freedom from f u e l

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s u p p l y concerns and accomplished i n f o r e i g n programs, has n o t been a c c e p t e d i n t h e United S t a t e s because of economic and i n s t i t u t i o n a l considerations. 3.4.5

Research and Development Needs f o r t h e LMR Concepts

3.4.5.1

Introduction

Two d i f f e r e n t p e r s p e c t i v e s are p r e s e n t e d i n c o n n e c t i o n w i t h LMR res e a r c h and development (R&D) needs. F i r s t , t h e viewpoint of t h e p l a n t d e s i g n e r i s r e f l e c t e d through a c o l l a t i o n of d e s i g n - s p e c i f i c R&D req u i r e m e n t s f o r t h e t h r e e LMR c o n c e p t s c o n s i d e r e d i n t h i s r e p o r t . Then c o n s i d e r a t i o n i s g i v e n t o g e n e r a l g o a l s f o r t h e U.S. LMR R&D program which could c o n t r i b u t e t o a h e a l t h y and c o m p e t i t i v e i n d u s t r y c o n s i d e r i n g t h e worldwide marketplace. 3.4.5.2

D e s i g n - S p e c i f i c R&D Requirements

Each d e s i g n e r of t h e t h r e e LMR c o n c e p t s c o n s i d e r e d by NPOVS r e c e n t l y corn l e t e d an assessment of s p e c i f i c R&D needs and r e p o r t e d conclus i o n s . '8-30 Appendix D p r e s e n t s summaries of t h e s e needs, where i n severa1 i n s t a n c e s , similar needs have been combined. These d e s i g n - s p e c i f i c ( 1 ) advanced c o r e d e s i g n t a s k s needs can be c l a s s i f i e d as f o l l o w s : which i n c l u d e d e v e l o p i n g improved n e u t r o n c o u n t i n g c h a n n e l s , e v a l u a t i n g s h i e l d i n g d e s i g n s , t e s t i n g s e l f - a c t u a t e d shutdown s y s t e m s , p e r f o r m i n g PRA a s s e s s m e n t s , and e v a l u a t i n g r e s p o n s e s t o a c c i d e n t s ; (2) shutdown h e a t removal e x p e r i m e n t s and a n a l y s e s t o e v a l u a t e d e s i g n e f f e c t i v e n e s s , d e s i g n margins, and immunity t o e x t e r n a l e v e n t s ; ( 3 ) f u e l r e l a t e d a c t i v i t i e s such as e v a l u a t i o n s of metal f u e l c y c l e s , h i g h burnup t e s t s of o x i d e f u e l s , and performance of t h e s e two f u e l s d u r i n g u p s e t s o r when breached; and ( 4 ) system- and component-related s t u d i e s emphasizing o p e r a t i n g p l a n t e x p e r i e n c e , scale model flow and t e m p e r a t u r e t e s t s , i n c o r p o r a t i o n of advanced i n s t r u m e n t a t i o n and c o n t r o l t e c h n o l o g i e s , and improving steam g e n e r a t o r performance. A l a r g e b a s e of t e s t e x p e r i e n c e e x i s t s f o r t h e o x i d e f u e l b u t t h a t f o r metal f u e l i s l i m i t e d . It i s a n t i c i p a t e d t h a t an e x t e n s i v e f u e l t e s t i n g program would be r e q u i r e d f o r metal f u e l b e f o r e p r o c e e d i n g t o commercial use. I n t h e French q u a l i f i c a t i o n of o x i d e f u e l s f o r LMFBR u s e , t h e t e s t i n g program i n c l u d e d an extended o p e r a t i o n w i t h r e f a b r i A similar e f f o r t f o r c a t e d f u e l from t h e r e p r o c e s s i n g d e m o n s t r a t i o n . metal f u e l may be prudent. R e p r o c e s s i n g and r e f a b r i c a t i o n are d i s c u s s e d more e x t e n s i v e l y i n Appendix E. 3.4.5.3

General R&D Goals f o r t h e U.S.

N a t i o n a l LMR Program

A n e c e s s a r y but perhaps not s u f f i c i e n t l i s t of includes the following:

g o a l s f o r LMR R&D

Develop an LMR d e s i g n which has a c l e a r , unique, and s i g n i f i c a n t advantage i n t h e m a r k e t p l a c e over o t h e r c o n c e p t s . The c u r r e n t des i g n s t u d i e s are judged t o be c o n s i s t e n t w i t h t h i s goal. However,

3-44 a small o r d e b a t a b l e a d v a n t a g e f o r LMRs may n o t be a d e q u a t e f o r p e n e t r a t i o n of a market dominated by LWR d e s i g n s . P r e s e n t programs a r e a p p r o p r i a t e l y d i r e c t e d toward t h e i n n o v a t i v e d e s i g n of a c o s t c o m p e t i t i v e , modern ( i . e . , i n c o r p o r a t i n g new t e c h n o l o g i e s ) , and i n L i c e n s a b i l i t y a d v a n t a g e s as w e l l as p u b l i c and h e r e n t l y s a f e LMR. u t i l i t y a c c e p t a n c e a l s o are i m p o r t a n t r e a s o n s f o r t h i s g o a l t o b e achieved. 2.

M a i n t a i n t h e o p t i o n f o r r a p i d i n c o r p o r a t i o n of b r e e d e r s and of a complete f u e l c y c l e i n t o t h e f u t u r e m a r k e t p l a c e . The p o t e n t i a l long-term market f o r b r e e d e r s is a s s u r e d u n l e s s n u c l e a r f i s s i o n Also, t h e r e e x i s t s a energy i s t o have o n l y a t r a n s i t o r y r o l e . p o s s i b i l i t y f o r s u b s t a n t i a l l y i n c r e a s e d s h o r t e r t e r m demand i f , f o r example, i n c r e a s e d burning of c o a l s h o u l d be found u n a c c e p t a b l e .

Complement t h e LMR R&D b e i n g performed by Europe and J a p a n s o t h a t t h e United States w i l l be i n a s t r o n g n e g o t i a t i n g p o s i t i o n t o exchange o u r accomplishments f o r e x p e r i e n c e from t h e i r more accelera t e d programs of d e m o n s t r a t i o n and c o m m e r c i a l i z a t i o n . Programs which t y p i f y c o n t r i b u t i o n s t o t h i s g o a l i n c l u d e advanced computer code development, materials r e s e a r c h , l i c e n s i n g r e f o r m , advanced d e s i g n s , m e t a l f u e l research, advanced i n s t r u m e n t a t i o n , c o n t r o l and s i m u l a t i o n , and development of double-wall steam g e n e r a t o r s .

C o n t r i b u t e t o a r e d u c t i o n i n l i c e n s i n g c o n c e r n s , c o s t l y d e s i g n marg i n s , and s p e c i a l systems r e s u l t i n g from t h e p o t e n t i a l f o r c o r e disruptive accidents. Each of t h e LMR d e s i g n s c o n s i d e r e d by NPOVS have a l r e a d y c o n t r i b u t e d t o t h i s g o a l . Advances i n t h e f u t u r e s h o u l d stress d e m o n s t r a t i o n of p a s s i v e s a f e t y f e a t u r e s , computer code v a l i d a t i o n , and e x p e r i m e n t a l v e r i f i c a t i o n of s p e c i f i c react i v i t y feedback e f f e c t s i n c o r p o r a t e d i n t o d e s i g n s .

Demonstrate, t e s t , and u t i l i z e t o t h e f u l l e s t e x t e n t p o s s i b l e advanced t e c h n o l o g i e s , components, and d e s i g n c o n c e p t s . Implementat i o n of R&D t o s a t i s f y t h i s g o a l would i n c r e a s e t h e a v a i l a b l e des i g n o p t i o n s , 3 1 t h e r e b y i n c r e a s i n g t h e l i k e l i h o o d of o p t i m i z i n g t h e d e s i g n t o accomplish a l a r g e r number of d e s i r a b l e o b j e c t i v e s and specifications. These advanced t e c h n o l o g i e s c o u l d i n c l u d e automat i o n , r e s e a r c h r e s u l t i n g i n h i g h e r p l a n t o p e r a t i n g t e m p e r a t u r e s and e f f i c i e n c i e s , u s e of a r t i f i c i a l i n t e l l i g e n c e , and i n c r e a s e d u s e of computers f o r c o n t r o l and s i m u l a t i o n , s u r v e i l l a n c e and d i a g n o s t i c s , d a t a d i s p l a y and v e r i f i c a t i o n , and maintenance f u n c t i o n s . Automat i o n may be v e r y i m p o r t a n t t o t h e l i c e n s i n g and economic o p e r a t i o n of m u l t i p l e modules which f e e d a common steam system.

Study and d e v e l o p containment c o n c e p t s which b o t h s i m p l i f y t h e o v e r a l l n u c l e a r system and e n s u r e p r o t e c t i o n a g a i n s t b o t h i n t e r n a l and e x t e r n a l e v e n t s , which may be judged c r e d i b l e . T h i s work must b e coupled c l o s e l y w i t h s o u r c e term e v a l u a t i o n s .

3-45

I n v e s t i g a t e LMR c o r e d e s i g n s which might be c o m p e t i t i v e u s i n g a once-through f u e l c y c l e . These s t u d i e s s h o u l d i n c l u d e t h e potent i a l u s e of Pu o b t a i n e d from f o r e i g n s o u r c e s . T h i s t a s k w i l l proba b l y r e q u i r e d e t e r m i n i n g an optimum c o r e geometry, power d e n s i t y , c o r e l i f e t i m e , and n e u t r o n energy. It could c o n t r i b u t e s i g n i f i c a n t l y t o c o m p e t i t i v e LMRs f o r a s c e n a r i o of low energy-growthrates. One such concept i s an u l t r a l o n g - l i f e c o r e which would r e q u i r e r e f u e l i n g o n l y a t major i n s p e c t i o n i n t e r v a l s of a p p r o x i mately every t e n years.

Develop and d e m o n s t r a t e t e c h n i c a l s o l u t i o n s t o t h e c h a l l e n g e s assoc i a t e d w i t h t h e LMR f u e l c y c l e which were i d e n t i f i e d i n t h e p r e v i o u s s e c t i o n of t h i s r e p o r t .

3.5.

HIGH TEMPERATURE REACTORS ( HTRs)

The f o c u s of NPOVS HTR e v a l u a t i o n i s on t h e modular HTR w i t h t h e steam g e n e r a t o r and c o r e i n s e p a r a t e s t e e l v e s s e l s connected by conAn e x t e n s i v e amount c e n t r i c c r o s s d u c t s i n a side-by-side c o n f i g u r a t i o n . p l~a c e of i n f o r m a t i o n has been d e r i v e d from t h e DOE HTR P r ~ g r a m . ~ ~To" ~ t h e s a f e t y and economic f e a t u r e s of t h e modular HTR i n p e r s p e c t i v e , t h e l a r g e HTGR [ 2240 MM(t) , 860 MW(e)] , which was t h e f o c u s of t h e DOE Program f o r s e v e r a l y e a r s , i s c a r r i e d by NPOVS as a p o i n t of r e f e r e n c e . A summary of i t s a d v a n t a g e s , d i s a d v a n t a g e s , and R&D needs can be found in Refs. 39 and 40 r e s p e c t i v e l y . Appendix F p r e s e n t s t h e g e n e r a l d e s i g n f e a t u r e s of a l a r g e HTGR as a r e f e r e n c e f o r HTR Technology t h a t w a s o r i g i n a l l y o r i e n t e d t o t h a t design.

3.5.1.

Design D e s c r i p t i o n s

Modular s t e e l - v e s s e l HTR development began i n The F e d e r a l R e p u b l i c of Germany (FRG) i n t h e l a t e 1970s. Concepts have been developed by Int e r a t o m , a s u b s i d i a r y of Kraftwerk Union (KWU) and by Hochtemperatur Reaktorbau (HRB) .4 1-42 K e r n f o r s c h u n g s a n l a g e (KFA) , t h e Nuclear Research C e n t e r a t J i i l i c h , h a s a l s o been v e r y a c t i v e i n t h e FRG program. They have t a k e n a d v a n t a g e of f a v o r a b l e HTR c h a r a c t e r i s t i c s (e.g. h i g h h e a t c a p a c i t y of t h e c o r e and r e f l e c t o r , h i g h t e m p e r a t u r e c a p a b i l i t y of t h e f u e l , l a r g e n e g a t i v e t e m p e r a t u r e c o e f f i c i e n t of r e a c t i v i t y ) t o d e v e l o p a s i m p l e r p l a n t t o ease r e g u l a t o r y , c o n s t r u c t i o n and f i n a n c i n g d i f f i c u l t i e s , as w e l l as minimize development r e q u i r e m e n t s . Both t h e I n t e r a t o m and t h e HRB modular HTR c o n c e p t s i n v o l v e s m a l l modules of 200 t o 250 MM(t) each. The t h e r m a l o u t p u t of s e v e r a l modules can be combined t o obtain a l a r g e r t o t a l plant capacity. T h i s approach o b v i o u s l y reduces t h e f i s s i o n p r o d u c t i n v e n t o r y i n any s i n g l e r e a c t o r and r e d u c e s t h e amount of h e a t which must be removed from a r e a c t o r c o r e i n t h e e v e n t of an a c c i d e n t , t h e r e b y c o n t r i b u t i n g t o a h i g h d e g r e e of s a f e t y . Both c o n c e p t s u t i l i z e pebble f u e l as do t h e two e x i s t i n g German HTRs [ t h e A r b e i t s g e m e i n s c h a f t Versuchs Reaktor (AVR) and t h e Thorium Hoch Temperatur Reaktor (THTR)]. The I n t e r a t o m concept p l a c e s t h e c o r e and steam g e n e r a t o r i n s e p a r a t e s t e e l v e s s e l s i n a side-by-side c o n f i g u r a t i o n , w h i l e i n t h e HRB concept t h e steam g e n e r a t o r i s l o c a t e d above t h e

3-46 For both c o n c e p t s , t h e r e a c t o r v e s s e l i s c o r e i n t h e same v e s s e l . housed i n a r e i n f o r c e d c o n c r e t e c a v i t y f o r b o t h confinement and biol o g i c a l shielding. A v e s s e l c o o l i n g system, mounted on t h e i n s i d e s u r f a c e of t h e c a v i t y w a l l , i s normally i n o p e r a t i o n c o o l i n g t h e c o n c r e t e and i s c a p a b l e of p r o v i d i n g decay h e a t removal by h e a t r a d i a t i o n from the uninsulated reactor vessel. Design p a r a m e t e r s ( s u c h as c o r e s i z e and power d e n s i t y ) f o r t h e s e modules were j u d i c i o u s l y combined w i t h g e n e r i c HTR f e a t u r e s so t h a t i n extreme a c c i d e n t s p u b l i c s a f e t y i s prov i d e d w i t h o u t t h e o p e r a t i o n of a c t i v e h e a t removal equipment. Engineered systems are employed, but t h e i r r o l e i s p r i m a r i l y f o r i n v e s t m e n t protection. KWU/ I n t e r a t o m i s a c t i v e l y p r o p o s i n g t h e i r p l a n t d e s i g n f o r near-term commercial g e n e r a t i o n of e l e c t r i c i t y and f o r c o g e n e r a t i o n of e l e c t r i c i t y and p r o c e s s h e a t . HRB proposes t h e i r concept f o r small e l e c t r i c i t y u s e r s and f o r p r o c e s s steam a p p l i c a t i o n . For t h e l o n g e r t e r m , I n t e r a t o m and HRB are d e v e l o p i n g t h e i r c o n c e p t s f o r advanced process h e a t purposes such as t h e p r o d u c t i o n of syngas t h r o u g h steam reforming of methane o r by steam g a s i f i c a t i o n of c o a l . For l a r g e r p l a n t s HRB o f f e r s t h e HTR 500 [500 MW(e)]

An i n f o r m a l b u t broad survey of US u t i l i t i e s by Gas Cooled Reactor A s s o c i a t e s i d e n t i f i e d a p r e f e r e n c e f o r p l a n t s i z e s i n t h e 200-700 MW(e) range f o r c a p a c i t y a d d i t i o n s beginning i n t h e mid- t o l a t e 1 9 9 0 ~ . ~ ~ Other more g e n e r a l s t u d i e s a l s o have i n d i c a t e d i n t e r e s t i n smaller plants. I n r e s p o n s e t o t h e s e f a c t o r s , t h e U.S. HTR Program w a s rea l i g n e d i n May 1984 t o e v a l u a t e t h e p o t e n t i a l f o r small r e a c t o r c o n c e p t s w i t h emphases on p l a n t i n v e s t m e n t p r o t e c t i o n and s a f e t y . In p a r t i c u l a r , t h e p l a n t d e s i g n should be such t h a t t h e r e would be no need f o r emergency s h e l t e r i n g o r e v a c u a t i o n of t h e p u b l i c as a consequence of l i c e n s ing-basis events. Four c o n c e p t s which r e s u l t e d from a p r e l i m i n a r y s c r e e n i n g p r o c e s s were : 1170-MW(t)

HTGR C y l i n d r i c a l P r i s m a t i c Core Concept; (Ref. 44)

1260-MW(t)

HTGR Annular Core P r i s m a t i c Concept; (Ref. 45)

250-MW(t)

Pebble Bed Reactor V e r t i c a l - I n - L i n e S t e e l Vessel Concept ( 4 u n i t s of 250 MW(t) e a c h ) ; (Ref. 46)

250-MW( t )

Pebble Bed R e a c t o r Side-by-Side Vessel Concept ( 4 u n i t s of 250 MW(t) e a c h ) . ( R e f . 35)

A Concept E v a l u a t i o n P l a n 3 4 s p e c i f i e d c r i t e r i a ( g e n e r a l l y c o n s i s t e n t w i t h NPOVS c r i t e r i a ) a g a i n s t which t h e s e p l a n t c o n c e p t s were e v a l u ated. As a r e s u l t , t h e modular HTR i n a side-by-side c o n f i g u r a t i o n w a s s e l e c t e d i n e a r l y 1985 as a p r e f e r r e d c o n c e p t . I n i t i a l l y , emphasis w a s p l a c e d on t h e p e b b l e bed c o r e c o n c e p t ; however, a s u b s e q u e n t e v a l u a t i o n

3-47

between p e b b l e and prism f u e l s l e d t o t h e s e l e c t i o n of a p r i s m a t i c c o r e i n September 1985. The p r i s m a t i c c o r e o b t a i n s h i g h e r c a p a c i t y w i t h The power l e v e l s up t o 350 MW(t) by employing an a n n u l a r c o r e design. h i g h e r power l e v e l reduces t h e p l a n t c a p i t a l c o s t p e r kW(e) f o r t h e p r i s m a t i c f u e l e d c o r e r e l a t i v e t o t h a t f o r t h e 250 MW(t) c y l i n d r i c a l c o r e pebble bed r e a c t o r . I n a d d i t i o n , t h e problem of compensating f o r r e a c t i v i t y i n s e r t i o n s due t o water i n g r e s s i s reduced i n t h e a n n u l a r core design. The c u r r e n t r e f e r e n c e modular HTR p l a n t c o n s i s t s of 4 x 350 MW(t) r e a c t o r u n i t s f o r a t o t a l c a p a c i t y of approximately 560 We) Through an i n t e g r a t e d approach, t h e modular HTR concept i s being designed t o meet t h e g o a l s of s a f e , economical p 0 w e r . 4 ~ To meet t h e s e g o a l s , t h e d e s i g n must s a t i s f y t h e f o l l o w i n g r e q u i r e m e n t s : 3 5 1.

E q u i v a l e n t a v a i l a b i l i t y f a c t o r of 80% w i t h planned downtime of less t h a n o r e q u a l t o 10% p e r year.

50 y r l i f e measured from i s s u a n c e of c o n s t r u c t i o n p e r m i t .

Have a t l e a s t 10% economic advantage o v e r t h e b e s t c o a l - f u e l e d a l t e r n a t i v e s o u r c e of e l e c t r i c i t y .

Capable of s t a r t of o p e r a t i o n i n mid 1990s.

S e p a r a t e t h e n u c l e a r and non-nuclear p o r t i o n s of p l a n t t o minimize t h e number of components and systems which m s t be proc u r e d , i n s t a l l e d , o p e r a t e d , and i n s p e c t e d t o n u c l e a r s t a n d a r d s .

S a t i s f y investment p r o t e c t i o n goals:

less t h a n 10% unscheduled u n a v a i l a b i l i t y

provide p r o t e c t i o n a g a i n s t long outages

l i m i t t h e c o s t of d e c o n t a m i n a t i o n and decommissioning

f r e uency of e v e n t s l e a d i n g t o p l a n t l o s s t o be less t h a n 10-2 p e r p l a n t y e a r

S a t i s f y HTGR s a f e t y g o a l s :

d o s e s n o t t o exceed EPA P r o t e c t i v e A c t i o n G u i d e l i n e s f o r p u b l i c e v a c u a t i o n down t o an a c c i d e n t f r e q u e n c y of 5 x 10-7 p e r p l a n t y e a r

meet NRC i n t e r i m s a f e t y g o a l s

The r e f e r e n c e modular HTR i s shown i n F i g u r e 3.7. A p l a n t would c o n s i s t of f o u r 350 MW(t) r e a c t o r modules g e n e r a t i n g steam f o r two nominal 300 MW(e) t u r b i n e g e n e r a t o r s t o produce a n e t p l a n t o u t p u t of 558 MW(e) ( o t h e r d e s i g n a l t e r n a t i v e s u s i n g 1 x 560 kW(e) and 4 x 140 MW(e) t u r b i n e s are also b e i n g examined i n t h e DOE program t o d e t e r m i n e t h e b e s t approach) 48

3-48

OANL-DWG 86-7363

CONTROL ROD DRIVE ASSEMBLY

REACTOR VESSEL ANNULAR PRISMATIC CORE MAIN CIRCULATOR

M A I N STEAM STEAM GENERATOR SHUTDOWN COOLIN HEAT EXCHANGER

STEAM GENERATOR

SHUTDOWN COOLING CIRCUIATOR/MOTOR

FEEDWATER INLET

F i g . 3.7. 350 MW(t) a n n u l a r p r i s m a t i c HTGR: p a t h d u r i n g normal o p e r a t i o n .

Primary c o o l a n t f l o w

3-49 Each r e a c t o r module i s housed i n a r e i n f o r c e d c o n c r e t e e n c l o s u r e The n u c l e a r i s l a n d con( s i l o ) which i s f u l l y embedded i n t h e e a r t h . s i s t s of f o u r e n c l o s u r e s and a d j a c e n t s t r u c t u r e s which house f u e l h a n d l i n g , helium p u r i f i c a t i o n , s t o r a g e , and t r a n s f e r s y s t e m s , t h e radwaste system, n u c l e a r i s l a n d c o o l i n g water s y s t e m s , and o t h e r e s s e n t i a l r e a c t o r s e r v i c e systems. A common c o n t r o l room i s used t o o p e r a t e a l l f o u r r e a c t o r s and t h e t u r b i n e p l a n t . Each 350 MW(t) u n i t c o n s i s t s of s e p a r a t e r e a c t o r and steam genera t o r vessels connected by a h o r i z o n t a l c o a x i a l c r o s s d u c t . The c o r e , g r a p h i t e r e f l e c t o r , c o r e s u p p o r t s t r u c t u r e , and r e s t r a i n i n g d e v i c e s are i n s t a l l e d i n the reactor vessel. The c u r r e n t c o r e c o n c e p t u s e s p r i s matic f u e l e l e m e n t s most of which w i l l be g e o m e t r i c a l l y i d e n t i c a l t o t h e The e l e m e n t s c o n t a i n Fort S t . Vrain standard (non-control) elements. v e r t i c a l t h r o u g h - h o l e s f o r c o o l a n t flow and b l i n d h o l e s f o r f u e l rods. The c o r e c o n s i s t s of f u e l e l e m e n t s i n an a n n u l u s between an i n n e r and A number of t h e e l e m e n t s o u t e r r e g i o n of hexagonal r e f l e c t o r elements. t o be p l a c e d a d j a c e n t t o t h e i n n e r r e f l e c t o r c o n t a i n an o f f - c e n t e r h o l e t o accommodate t h e i n s e r t i o n of r e s e r v e shutdown materials. Although t h e i n t e r n a l c o n f i g u r a t i o n of t h e s e e l e m e n t s d i f f e r from t h o s e used a t A number of t h e F o r t S t . V r a i n , t h e e x t e r n a l geometry i s t h e same. i n t e r n a l and e x t e r n a l r e f l e c t o r e l e m e n t s which bound t h e c o r e c o n t a i n o f f - c e n t e r h o l e s f o r c o n t r o l rod i n s e r t i o n . The hexagonal f u e l and r e f l e c t o r e l e m e n t s are d e s i g n e d f o r p e r i o d i c replacement v i a t h e c o n t r o l The o u t e r m o s t r a d i a l r e f l e c t o r r o d p e n e t r a t i o n s i n t h e v e s s e l t o p head. e l e m e n t s are i r r e g u l a r i n shape s o as t o i n t e r f a c e w i t h t h e h e x a g o n a l l y s t e p p e d o u t e r boundary of r e p l a c e a b l e r e f l e c t o r e l e m e n t s and t h e l a t e r a l core support s t r u c t u r e . G r a v i t y - a s s i s t e d c o n t r o l rod d r i v e mechanisms a r e p o s i t i o n e d above t h e r a d i a l r e f l e c t o r t o o p e r a t e c o n t r o l rods i n t h e c h a n n e l s i n t h e i n n e r and o u t e r r e f l e c t o r . The a c t i v e c o r e c o n s i s t s of 66 10-block h i g h columns of f u e l e d elements. T h i s makes t h e a n n u l a r c o r e c o n f i g u r a t i o n t h r e e e l e m e n t s wide and g i v e s an a v e r a g e c o r e power d e n s i t y of 5.91 W/cm3. The f u e l elements c o n t a i n 1.27 cm (0.50 i n . ) d i a m e t e r by 6.35 c m (2.50 i n . ) l o n g f u e l rods c o n s i s t i n g of c o a t e d UCO and THO2 p a r t i c l e s of low e n r i c h e d uranium (LEU) f u e l (U-235 < 2 0 % ) bonded i n a g r a p h i t e matrix. Refueling i s accomplished w i t h t h e r e a c t o r s h u t down and t h e v e s s e l d e p r e s s u r ized. The r e f u e l i n g o p e r a t i o n s are p r e d i c a t e d on a t h r e e - y e a r f u e l r e s i d e n c e t i m e whereby h a l f t h e f u e l e l e m e n t s are r e p l a c e d a t t h e inThe new f u e l i s p l a c e d i n t o a l t e r n a t e columns t e r v a l s of 18 months. a d j a c e n t t o t h e half-burned f u e l . During r e f u e l i n g , a l l t h e f u e l e l e m e n t s i n t h e c o r e are moved w i t h i n t h e v e s s e l i n 60 deg s e c t o r s a t a t i m e ; f r e s h and s p e n t f u e l p a s s through t h e t o p head r e f u e l i n g p e n e t r a t i o n s which are l o c a t e d o v e r t h e i n n e r - r e f l e c t o r - t o - c o r e interface. Each s e c t o r i s r e b u i l t w i t h h a l f new and h a l f - b u r n e d f u e l . At discharge, the spent f u e l burnup of t h e equilibrium cycle is 8 2 , 4 6 0 MbJD/tonne. During each r e f u e l i n g , o n e - s i x t h of t h e r e f l e c t o r e l e m e n t s a d j a c e n t t o t h e a c t i v e c o r e i s r e p l a c e d which c o r r e s p o n d s t o a n i n e year residence t i m e . An a l t e r n a t e c y c l e h a s a l s o been e v a l u a t e d whereby t h e e n t i r e c o r e i s f u e l e d as a b a t c h , w i t h a l i f e t i m e of a b o u t

3-50 2.7 yr. T h i s c y c l e i s s t a t e d t o have n e a r l y as f a v o r a b l e c o s t s and t o r e q u i r e less f r e q u e n t shutdown f o r r e f u e l i n g . Replacement of f u e l and r e f l e c t o r e l e m e n t s i s performed w i t h t h e f u e l h a n d l i n g machine (FHM) which is placed over t h e i n n e r p e n e t r a t i o n c o r r e s p o n d i n g t o t h e s e c t o r t o be removed. The FHM e l e v a t e s t h e s p e n t elements i n t o a f u e l t r a n s f e r cask. The f u e l t r a n s f e r c a s k , loaded t o i t s maximum w i t h f i v e e l e m e n t s , i s used t o p l a c e t h e e l e m e n t s i n a f u e l storage w e l l . Here t h e elements a r e dry-cooled b e f o r e shipment o f f site. The r e a c t o r p l a n t c o o l i n g w a t e r system i s used t o remove h e a t from t h e w e l l . Helium flows downward through t h e c o r e c o o l a n t c h a n n e l s t o an outl e t plenum and t h e n through t h e c e n t r a l duct of t h e c r o s s d u c t t o t h e It t h e n flows downward a c r o s s t h e once t o p of t h e steam g e n e r a t o r . through h e l i c a l c o i l steam g e n e r a t o r w i t h u p h i l l b o i l i n g i n t h e steam g e n e r a t o r tubes. Cool helium i s drawn from t h e bottom of t h e steam gene r a t o r and flows through an annulus s u r r o u n d i n g t h e steam g e n e r a t o r o u t e r shroud t o t h e c i r c u l a t o r l o c a t e d on t o p of t h e v e s s e l . The c i r c u l a t o r d i s c h a r g e s helium t o a plenum from which helium flows through t h e o u t e r annulus of t h e c r o s s d u c t t o t h e r e a c t o r v e s s e l . It t h e n flows upward through c h a n n e l s i n the o u t e r g r a p h i t e r e f l e c t o r t o a plenum above t h e t o p of t h e core. The r e a c t o r i n t e r n a l s t r u c t u r e s c o n s i s t of g r a p h i t e and m e t a l l i c components. The major g r a p h i t e components are t h e o u t e r permanent ref l e c t o r , bottom r e f l e c t o r , c o r e s u p p o r t p o s t s , and t o p r e f l e c t o r . The major m e t a l l i c components are t h e c o r e s u p p o r t p l a t e , c o r e b a r r e l l a t e r a l s u p p o r t s t r u c t u r e , and t h e h o t d u c t p o r t i o n of t h e c o n c e n t r i c cross duct. The r e a c t o r i n t e r n a l s are d e s i g n e d f o r t h e f u l l o p e r a t i n g l i f e , but are a l s o designed t o be i n s p e c t a b l e , removable, and replaceable, i f necessary. The main c i r c u l a t o r , a v a r i a b l e speed, motor-driven s i n g l e s t a g e c e n t r i f u g a l compressor u s i n g g a s / m a g n e t i c b e a r i n g s , i s mounted v e r t i c a l l y on t o p of t h e s t e a m g e n e r a t o r v e s s e l . Design p a r a m e t e r s are summarized i n Table 3 . 2 . The b a s i c approach h a s been t o j u d i c i o u s l y s e l e c t d e s i g n parameters and e n g i n e e r e d systems s o t h a t t h e y combine with i n h e r e n t HTR f e a t u r e s t o y i e l d a h i g h d e g r e e of p a s s i v e s a f e t y , and t o p r o v i d e i n v e s t m e n t p r o t e c t i o n as d i s c u s s e d i n the following paragraphs.

Two i n d e p e n d e n t , d i v e r s e r e a c t i v i t y c o n t r o l / r e a c t o r shutdown s y s tems are provided. The primary system u t i l i z e s c o n t r o l r o d s l o c a t e d i n t h e i n n e r and o u t e r r e p l a c e a b l e r e f l e c t o r . The second system, t h e res e r v e shutdown system (RSS), c o n s i s t s of boronated g r a p h i t e p e l l e t s i n s t o r a g e hoppers which can be d i s c h a r g e d i n t o c h a n n e l s i n t h e innermost row of f u e l columns. R e a c t i v i t y c o n t r o l requirements f o r b a s i c operat i o n s , i n c l u d i n g c o l d shutdown, are a d e q u a t e l y covered by t h e r e f l e c t o r rod systems a l o n e , with at-power o p e r a t i o n s p o s s i b l e w i t h o u t i n s e r t i o n

3-51

T a b l e 3.2.

Summary of major d e s i g n f e a t u r e s of m o d u l a r HTR ( side-by-side configuration)

Power p e r m o d u l e , MW(t)

3 50

C o r e power d e n s i t y , kW/1

5.91

Core i n l e t t e m p e r a t u r e ,

2 58

Core o u t l e t t e m p e r a t u r e ,

687

O C

H e l i u m flow rate, kg/sec

156.6

H e l i u m flow d i r e c t i o n

downward

Helium p r e s s u r e , MPa ( p s i a )

6.38

Active core diameter, m

1.65 i n n e r , 3.5 o u t e r

Active core height, m

7.8

Fuel element

p r i s m a t i c hex-block, x 79.3 cm h e i g h t

Fuel

LEU/Th

E q u i li b r i u m r e l o a d ,

A v e r a g e d i s c h a r g e h r n u p , MWd/kg

R e a c t o r v e s s e l material

82.5

1.0

Low a l l o y steel-Mn-Mo,

Class 1 Reactor vessel,

7.44

OD, m

R e a c t o r vessel t h i c k n e s s ,

Reactor v e s s e l h e i g h t , m

13.3 21.95

Steam c o n d i t i o n , p r e s s u r e ma ( p s i a ) temperature, O C

Net t h e r m a l e f f i c i e n c y , %

20.78 c m s i d e s

965/881

kg :U/Th

Radial r e f l e c t o r thickness,

(925)

17.3 541 39.6

(2515)

Sa 533 G r B

3-52 of t h e i n n e r - r e f l e c t o r rods. Cold shutdown w i t h maximum p o s i t i v e react i v i t y due t o water i n g r e s s r e q u i r e s t h e combined i n s e r t i o n of t h e r e f l e c t o r r o d s and t h e RSS. During a c o n d u c t i o n cooldown e v e n t , t h e i n n e r c o n t r o l r o d s could be damaged because of h i g h t e m p e r a t u r e s . To a v o i d damage, a l t h o u g h i t does n o t a f f e c t s a f e t y , a c o n t r o l r o d operat i o n a l s t r a t e g y has been adopted where t h e i n n e r r o d s are n o r m a l l y used f o r s t a r t u p t o 25% power and f o r normal c o l d shutdown. Steam g e n e r a t o r t u b e l e a k s are d e t e c t e d by a m o i s t u r e m o n i t o r I f excessive moisture is detected, located at t h e c i r c u l a t o r outlet. t h e steam g e n e r a t o r i s i s o l a t e d and dumped and t h e main c i r c u l a t o r i s stopped. A shutdown c o o l i n g system (SCS) i s p r o v i d e d t o a c h i e v e and m a i n t a i n t h e r e a c t o r t h e r m a l c o n d i t i o n s r e q u i r e d f o r m a i n t a i n e n c e i n t h e e v e n t of f a i l u r e of t h e main h e a t t r a n s p o r t system (HTS) and t o h e l p meet t h e overall plant a v a i l a b i l i t y goal. The SCS i s l o c a t e d i n t h e bottom of t h e r e a c t o r v e s s e l and c o n s i s t s of a h e a t exchanger and a c i r c u l a t o r w i t h a submerged motor.

The r e a c t o r c a v i t y i s provided w i t h a n a t u r a l d r a f t a i r c o o l i n g system ( K C C S ) , Fig. 3 . 8 . It c o n s i s t s of c o o l i n g p a n e l s mounted on t h e The dec a v i t y w a l l through which a i r c i r c u l a t e s by n a t u r a l c o n v e c t i o n . s i g n has no v a l v e s o r a c t i v e components. The s u r f a c e of t h e p a n e l s s e r v e s as a b a r r i e r s e p a r a t i n g t h e o u t s i d e atmosphere from t h e r e a c t o r c a v i t y atmosphere. The system u s e s f o u r s e p a r a t e i n l e t / o u t l e t s t r u c t u r e s t o minimize t h e p o s s i b i l i t y of flow blockage. In addition, the f o u r loops are i n t e r c o n n e c t e d by i n l e t / o u t l e t plenums i n t h e c o o l i n g panels. This p r o v i d e s a h e a t s i n k s u f f i c i e n t f o r decay h e a t removal i n t h e e v e n t t h e main h e a t t r a n s p o r t system ( s t e a m g e n e r a t o r and main h e l i u m c i r c u l a t o r ) and t h e shutdown c o o l i n g system a r e n o t a v a i l a b l e . Heat t r a n s p o r t from t h e r e a c t o r c o r e i s by n a t u r a l p r o c e s s e s of conduct i o n and r a d i a t i o n (and c o n v e c t i o n i f t h e primary s y s t e m i s p r e s s u r i z e d ) through t h e c o r e t o t h e v e s s e l w a l l and by r a d i a t i o n and c o n v e c t i o n t o t h e cooling panels. The r e a c t o r u t i l i z e s a confinement equipped w i t h dampers which open on e x c e s s i v e p r e s s u r e l o a d s r e s u l t i n g from f e e d w a t e r , main steam, o r rea c t o r coolant l i n e ruptures. Program s t u d i e s i n d i c a t e t h a t t h e f i s s i o n product releases from t h e c o r e are small enough t h a t r e l i a n c e need n o t be p l a c e d on c o n v e n t i o n a l p r e s s u r e - t i g h t c o n t a i n m e n t o r a confinement w i t h a f i l t e r system t o meet t h e d e f i n e d s a f e t y c r i t e r i a . For decay h e a t removal, under p r e s s u r i z e d o r d e p r e s s u r i z e d condit i o n s , t h e main c o o l i n g loop ( c o n s i s t i n g of t h e main c i r c u l a t o r and t h e steam g e n e r a t o r ) i s t h e f i r s t o p t i o n . If e i t h e r t h e main c i r c u l a t o r o r t h e steam g e n e r a t o r i s not o p e r a t i o n a l , t h e n f o r c e d c i r c u l a t i o n u s i n g t h e shutdown c o o l i n g system i s t h e n e x t o p t i o n f o r e i t h e r p r e s s u r i z e d o r depressurized conditions. The n e x t o p t i o n i s t o remove decay h e a t t h r o u g h t h e v e s s e l w a l l by r a d i a t i o n t o t h e RCCS. T h i s system i s d e s i g n e d t o l i m i t t h e f u e l t e m p e r a t u r e s t o 1200째C under p r e s s u r i z e d c o n d i t i o n s (when t h e r e can be a s i g n i f i c a n t r e d i s t r i b u t i o n of h e a t

3-53

ORNL-DWG 86-4054 ETD

r7 I

.....'.. .. *.a .

FEATURES :

COOLS THROUGH PANEL WALL

OPERATES UNDER All MODES OF REACTOR OPERATION.

SIMPLE TO OPERATE. VIRTUALLY MAINTENANCE FREE.

F i g . 3.8.

R e a c t o r c a v i t y c o o l i n g system.

3-54 w i t h i n t h e c o r e by n a t u r a l c o n v e c t i o n ) and t o 1600째C under d e p r e s s u r i z e d conditions.

3.5.2

C l a i m s , Advantages, and Disadvantages E v a l u a t e d A g a i n s t C r i t e r i a , E s s e n t i a l and D e s i r a b l e C h a r a c t e r i s t i c s

The claims and r e p o r t e d a d v a n t a g e s of t h e modular HTR are d i s c u s s e d b r i e f l y as f o l l o w s i n t h e o r d e r of t h e c r i t e r i a f i r s t and e s s e n t i a l and d e s i r a b l e c h a r a c t e r i s t i c s second. A more d e t a i l e d e v a l u a t i o n of modular HTR claims has been i n c l u d e d i n Appendix G. 1.

P u b l i c Risk: While t h e c a l c u l a t e d r i s k t o t h e p u b l i c h a s n o t been q u a n t i f i e d f o r t h e modular HTR, t h e r e are i m p o r t a n t f e a t u r e s which p r o v i d e t h e d e s i g n w i t h a high d e g r e e of p a s s i v e s a f e t y , and t h e r e b y a l s o p r o v i d e c o n f i d e n c e t h a t t h e c a l c u l a t e d r i s k t o t h e p u b l i c due t o a c c i d e n t s w i l l be e q u a l t o o r less t h a n t h e c a l c u l a t e d r i s k a s s o c i a t e d w i t h t h e b e s t modern LWRs. These f e a t u r e s are: 0

The c a p a b i l i t y f o r a f t e r h e a t removal through t h e v e s s e l w a l l by n a t u r a l h e a t t r a n s p o r t mechanisms ( c o n v e c t i o n , c o n d u c t i o n , and r a d i a t i o n ) . T h i s c a p a b i l i t y has been d e m o n s t r a t e d p a r t i a l l y on t h e smaller e x p e r i m e n t a l AVR which s h a r e s f e a t u r e s of t h e modular HTR. Future c o n f i r m a t o r y e x p e r i m e n t a t i o n f o r more g e n e r a l l y a p p l i c a b l e d a t a i s being c o n s i d e r e d and may be p o s s i b l e a t t h e AVR s u b j e c t t o t h e a p p r o v a l of t h e German a u t h o r i t i e s .

Very good r e t e n t i o n of f i s s i o n p r o d u c t s w i t h i n t h e f u e l t o high temperatures. This f e a t u r e h a s been d e m o n s t r a t e d by U.S. and German c o a t e d p a r t i c l e f u e l systems e x p e r i e n c e and i n f u e l t e s t programs.

No need f o r a f a s t a c t i n g shutdown system f o r c o r e h e a t u p e v e n t s , which a g a i n h a s been d e m o n s t r a t e d on o t h e r HTRs.

Other p o t e n t i a l l y s e v e r e a c c i d e n t s , such as major water a n d / o r a i r i n g r e s s e v e n t s , have been argued t o be of such low consequence o r low p r o b a b i l i t y by v i r t u e of system d e s i g n t h a t t h e s e t y p e s of a c c i d e n t s pose no s i g n i f i c a n t p u b l i c r i s k . However, t h e NRC may r e q u i r e t h a t t h e s e a c c i d e n t s be f a c t o r e d i n t o t h e c o s t b e n e f i t a n a l y s i s of t h e u s e of confinement v e r s u s containment.

Investment Risk: The p r o b a b i l i t y of l o s s of i n v e s t m e n t f o r t h e modular HTR is claimed t o be less t h a n p e r year. This claim r e q u i r e s independent review, b u t many of t h e f e a t u r e s which p r e c l u d e o r r e d u c e t h e e f f e c t of i n c i d e n t s on p u b l i c s a f e t y can be argued as being f a v o r a b l e t o i n v e s t m e n t p r o t e c tion.

3-55 3.

Economic Competitiveness: U n t i l t h e p l a n t d e s i g n i s complete and commodity r e q u i r e m e n t s d e t e r m i n e d , a f i r m estimate of c o s t cannot be made. With r e g a r d t o meeting t h e f i n a n c i a l g o a l s of t h e u t i l i t y , t h e a b i l i t y t o add c a p a c i t y i n small i n c r e m e n t s as w e l l as t h e p o t e n t i a l f o r a c h i e v i n g s h o r t c o n s t r u c t i o n t i m e through f a c t o r y f a b r i c a t i o n should reduce t h e u t i l i t i e s ' c a p i t a l i n v e s t m e n t exposure and i n v e s t m e n t r i s k , t h e r e b y h e l p i n g t o m e e t t h e i r f i n a n c i a l goals. With r e g a r d t o a c c e p t a b l e busbar c o s t s , f a c t o r y f a b r i c a t i o n of modules coupled w i t h t h e relat i v e l y h i g h burnup a c h i e v a b l e w i t h HTR f u e l c y c l e s may comp e n s a t e f o r h i g h e r f u e l f a b r i c a t i o n c o s t s t y p i c a l of HTRs and p o t e n t i a l l y higher d i s t r i b u t e d c a p i t a l cost usually associated w i t h smaller s i z e d p l a n t s . The u s e of n u l t i p l e modules may a l s o i n c r e a s e o v e r a l l a v a i l a b i l i t y , a l t h o u g h a t lower power l e v e l s , t h e r e b y p r o v i d i n g f l e x i b i l i t y i n s c h e d u l i n g outages. Assumptions about a v a i l a b i l i t y f o r t h e modular p l a n t s p l a y a n important r o l e i n e s t i m a t i n g o v e r a l l competitiveness with both t h e c o a l f i r e d and t h e b e t t e r c u r r e n t g e n e r a t i o n LWR p l a n t s .

P r o b a b i l i t y of Cost/Schedule Overruns: The DOE and t h e ind u s t r i a l proponents r e c o g n i z e t h e need f o r complete d e s i g n before i n i t i a t i n g construction. D e t a i l e d d e s i g n and a s s o c i a t e d s t u d i e s of c o n s t r u c t i o n needs, o p t i o n s and c o s t s s t i l l remain t o be completed, so t h a t c o s t and s c h e d u l e f a c t o r s cannot be quantified. However, t h e DOE funded program h a s produced i n d e p t h s t u d i e s of c o n s t r u c t i o n needs, o p t i o n s , and c o s t s f o r t h e modular HTR so t h a t u n c e r t a i n t i e s should be w e l l d e f i n e d .

Licensability: The modular HTR has a d r a f t l i c e n s i n g plan. The DOE and i n d u s t r i a l proponents are a c t i v e l y engaged i n E a r l y c o n c u r r e n c e on l i c e n s i n g may be d i a l o g u e w i t h NRC-NRR. e s s e n t i a l t o meeting t h e 2000-2010 t i m e frame f o r commercialDOE and t h e i n d u s t r i a l proponents p l a n t o s e c u r e an ization. NRC f i n a l d e s i g n a p p r o v a l (FDA) by 1996. A preliminary s a f e t y i n f o r m a t i o n document (PSID) w i l l be s u b m i t t e d i n CY 1986. There i s a l s o a u t i l i t y e f f o r t l e d by t h e Tennessee V a l l e y A u t h o r i t y (TVA) which p r o p o s e s j o i n t f u n d i n g of a s i n g l e p l a n t t o d e m o n s t r a t e l i c e n s a b i l i t y by t e s t ; however, such t e s t i n g p r o b a b l y could not a d d r e s s a l l s a f e t y q u e s t i o n s p a r t i c u l a r l y t h o s e beyond d e s i g n b a s i s a c c i d e n t s such as a major a i r i n g r e s s , acts of s a b o t a g e and seismic e v e n t s .

Demonstration of R e a d i n e s s : Many f e a t u r e s of t h e modular HTR a r e o r w i l l have been demonstrated i n t h e German AVR p l a n t b e f o r e t h e modular HTR is o f f e r e d commercially. A successful d e m o n s t r a t i o n of h i g h powered, g a s / m a g n e t i c b e a r i n g c i r c u l a t o r s would r e p r e s e n t a s i g n i f i c a n t c o n t r i b u t i o n t o t h e d e m o n s t r a t i o n of r e a d i n e s s s i n c e most of t h e o t h e r major component techn o l o g i e s e i t h e r are borrowed o r have evolved from AVR, THTR, and F o r t St. Vrain e x p e r i e n c e . More f u e l t e s t i n g i s a l r e a d y planned t o s u p p o r t l i c e n s i n g a s w e l l as normal o p e r a t i o n requirements.

3-56 7.

m e r Competence: The o p e r a t i o n of multi-module p l a n t s may pose new c o n c e r n s about i n t e r d e p e n d e n c e and common mode i n t e r a c t i o n s of systems. Such c o n c e r n s may i n f l u e n c e NRC mandates on a c c e p t a b l e c o n t r o l c o n f i g u r a t i o n s which may i n t u r n be more c o s t l y o r manpower i n t e n s i v e t h a n c u r r e n t l y e n v i s i o n e d ; howe v e r , t h e o v e r a l l t e c h n o l o g y of t h e modular HTR a p p e a r s t o be as r e a d i l y a s s i m i l a b l e as LWR technology. The l e s s o n s from t h e F o r t S t . V r a i n HTGR a l s o a p p e a r t o be clear t o a p o t e n t i a l o w n e r / o p e r a t o r of an HTR. Some of t h e s e l e s s o n s are: (1) keep m o i s t u r e o u t of t h e primary system and any o t h e r p a r t of t h e p l a n t where i t can c a u s e c o r r o s i o n [which s h o u l d be helped i n t h e modular d e s i g n by i n c o r p o r a t i n g hardware f e a t u r e s based on l e s s o n s l e a r n e d t o d a t e ] , ( 2 ) m a i n t a i n e x c e l l e n t secondary c o o l a n t c h e m i s t r y , ( 3 ) m a i n t a i n an i n t e n s i v e and e x t e n s i v e s u r v e i l l a n c e program of ( 1 ) and ( 2 ) above, ( 4 ) e n s u r e q u a l i t y and c o n f i r m a t o r y t e s t i n g of b o t h o r i g i n a l and r e p l a c e m e n t materials and equipment, and (5) m a i n t a i n a c l e a n p h y s i c a l plant. The l a r g e t h e r m a l margins i n h e r e n t i n t h e HTR f u e l s y s tems and t h e low g r a p h i t e c o r r o s i o n rates i n t h e p r e s e n c e of numerous m o i s t u r e i n g r e s s e v e n t s a t F o r t S t . V r a i n could l u l l p l a n t d e s i g n e r s and o p e r a t o r s i n t o a f a i l u r e t o r e c o g n i z e t h e Some of t h e observed opers i g n i f i c a n c e of o p e r a t i n g problems. a t i o n a l problems a t F o r t S t . V r a i n have i n c l u d e d t h e e f f e c t of m o i s t u r e on l e a c h i n g and d i s t r i b u t i o n of o t h e r c o r r o s i v e mater i a l s (e.g., c h l o r i d e s ) , t h e a p p a r e n t i n a b i l i t y t o d e t e c t abnormal c o n t r o l c o n f i g u r a t i o n s and r e a c t i v i t y a n o m a l i e s q u i c k l y (e.g. , c o n f i r m i n g s u b c r i t i c a l i t y by e x c o r e d e t e c t o r s and d e t e c t i n g dropped c o n t r o l m a t e r i a l ) and t h e p o s s i b l e i n t e r dependence of redundant emergency ac power systems. These t y p e s of s i t u a t i o n s s h o u l d not be r e p e a t e d w i t h t h e modular HTR.

Essential Characteristics: Many of t h e e s s e n t i a l c h a r a c t e r i s t i c s are i n t e g r a l r e q u i r e m e n t s f o r meeting one o r more of t h e c r i t e r i a and as such are d i s c u s s e d more f u l l y above. However, i n g e n e r a l , t h e modular HTR h a s promise of a c h i e v i n g many o f t h e s e c h a r a c t e r i s t i c s as o u t l i n e d , i n some cases r e p e t i t i v e l y , below: a.

High a v a i l a b i l i t y due t o u s e of s m a l l - s i z e d t u r b i n e s and m o d u l a r i t y which a l l o w s h i g h e r a v a i l a b i l i t y a t reduced power.

Maximum u s e of shop f a b r i c a t i o n of r e a c t o r systems

A h i g h d e g r e e of p a s s i v e s a f e t y

P o t e n t i a l l y no need f o r d e v e l o p i n g o r d e m o n s t r a t i n g a p l a n f o r e v a c u a t i o n of t h e p u b l i c beyond t h e s i t e boundary

P o t e n t i a l f o r demonstrating f e a t u r e s important f o r passive safety

3-57

Low t h e r m a l d i s c h a r g e (due t o h i g h t h e r m a l e f f i c i e n c y )

Low r a d i o a c t i v e e f f l u e n t as d e m o n s t r a t e d by Peach Bottom 1, Dragon, F o r t S t . V r a i n and AVR e x p e r i e n c e

Low i n v e s t m e n t r i s k t o t h e u t i l i t y r e s u l t i n g from a d d i n g c a p a c i t y i n small i n c r e m e n t s and from what i s i n t e n d e d t o be a s i m p l e r approach t o meeting s a f e t y r e q u i r e m e n t s and licensing.

Desirable Characteristics: S e v e r a l of t h e s e c h a r a c t e r i s t i c s are a d d r e s s e d i n r e g a r d t o c r i t e r i a . The advantageous ones are l i s t e d a g a i n as f o l l o w s . The modular HTR a p p e a r s t o have modest RD&D r e q u i r e m e n t s , r e l a t i v e e a s e i n s i t i n g based on proj e c t e d low s o u r c e t e r m s f o r b o t h normal o p e r a t i o n (worker expos u r e and e f f l u e n t s ) and a c c i d e n t c o n d i t i o n s , good f u e l u t i l i z a t i o n ( h i g h b u r n u p ) , h i g h t h e r m a l e f f i c i e n c y , high vers a t i l i t y i n a p p l i c a t i o n because of t h e p r o d u c t i o n of h i g h c o o l a n t t e m p e r a t u r e s , and a low v i s u a l p r o f i l e through f u l l embedment. F u l l embedment and p a s s i v e s a f e t y s h o u l d a l s o cont r i b u t e t o a h i g h d e g r e e of s a b o t a g e r e s i s t a n c e . The claim i s made t h a t t h e u s e of low e n r i c h e d uranium i n c r e a s e s r e s i s t a n c e t o p r o l i f e r a t i o n and d i v e r s i o n and t h a t a p p e a r s t o be t h e case f o r t h e f r e s h f u e l s u p p l y . Also, t h e HTR s p e n t f u e l a p p e a r s t o have a h i g h r e s i s t a n c e t o d i v e r s i o n and p r o l i f e r a t i o n t e c h nologies.

The p o t e n t i a l d i s a d v a n t a g e s are d i s c u s s e d as f o l l o w s : 1.

P u b l i c Risk: As a l l u d e d t o under t h e d i s c u s s i o n of a d v a n t a g e s , t h e r e s o l u t i o n of c o n c e r n s f o r s e v e r e a c c i d e n t s w i l l p r e f e r a b l y be h a n d l e d by p r o b a b i l i s t i c r i s k a n a l y s e s t o d e m o n s t r a t e a low c o n t r i b u t i o n t o t h e o v e r a l l r i s k t o t h e public. If requirements such as t h e u s e of i n e r t e d containment are imposed, overa l l c o s t s w i l l increase.

I n v e s t m e n t Risk:

Economic C o m p e t i t i v e n e s s : The p o s s i b i l i t y of h i g h e r c o s t s f o r f u e l f a b r i c a t i o n and p l a n t c a p i t a l i n v e s t m e n t a r e a c o n c e r n ; as is t h e a v a i l a b i l i t y which w i l l be a c h i e v e d . Independent e v a l u a t i o n s a p p e a r p r u d e n t t o perform.

P r o b a b i l i t y of C o s t / S c h e d u l e Overruns: S i n c e t h i s i s a new c o n c e p t , i t i s p a r t i c u l a r l y i m p o r t a n t t h a t t h e d e s i g n is completed before construction begins. The c u r r e n t approach i s based on d e f i n i n g “top-down“ r e q u i r e m e n t s from which d e s i g n d a t a needs and RD&D w i l l proceed u s i n g f u n c t i o n a l a n a l y s i s . C o n s t r u c t i o n p l a n s and s c h e d u l e s must be c o o r d i n a t e d c a r e f u l l y w i t h t h e a v a i l a b i l i t y of d e s i g n and s a f e t y r e l a t e d d a t a .

Licensability: A s mentioned above, t h e a n a l y s i s r e q u i r e m e n t s and e x p e c t e d d e s i g n needs i n r e s p o n s e t o “beyond d e s i g n b a s i s

Independent a s s e s s m e n t s a r e needed.

3-58 a c c i d e n t s " must be s e t t l e d , p r e f e r a b l y , as e a r l y as p o s s i b l e i n the design process. I n t h e post-TMI l i c e n s i n g environment, t h e modular HTR could s t i l l f a c e defense-in-depth r e q u i r e m e n t s such as c o n t a i n m e n t , emergency ac power s o u r c e s and s a f e t y g r a d e components i n t h e b a l a n c e of p l a n t . These can have a s e v e r e e f f e c t on i n c r e a s i n g p l a n t c o s t s i f imposed. Seismic c o n s i d e r a t i o n s w i t h r e g a r d t o t h e r e a c t o r c o r e and t h e side-by-side c o n n e c t i n g p i p e must a l s o be a d d r e s s e d f o r l i c e n s i n g .

3.5.3

Demonstration of Readiness: Other t h a n answering q u e s t i o n s about needing h i g h a v a i l a b i l i t y f o r o v e r a l l c o m p e t i t i v e economics, t h e modular HTR would a p p e a r t o have a lesser r e q u i r e ment f o r a d e m o n s t r a t i o n p l a n t because of AVR and THTR e x p e r i e n c e and t h e a b i l i t y t o i n c o r p o r a t e l e s s o n s l e a r n e d a t F o r t St. Vrain. Owner Competence: No s p e c i f i c d i s a d v a n t a g e i d e n t i f i e d , howe v e r , as i n d i c a t e d under a d v a n t a g e s , a p o t e n t i a l o w n e r / o p e r a t o r s h o u l d be thoroughly f a m i l i a r w i t h d e t a i l s of t h e e n g i n e e r i n g and l i c e n s i n g e x p e r i e n c e a t S t . Vrain. The l e s s o n s l e a r n e d are p o s i t i v e with respect t o avoiding p o t e n t i a l p i t f a l l s . E s s e n t i a l C h a r a c t e r i s t i c s : The r e l a t i v e l y low power per module [-350 MW(t)] does a f f e c t t h e c a p i t a l c o s t as a d i s a d v a n t a g e . The side-by-side HTR module has a l s o been q u e s t i o n e d because of p o t e n t i a l l y a d v e r s e seismic r e s p o n s e a t t h e c o n n e c t i n g p i p e between t h e r e a c t o r and steam g e n e r a t o r v e s s e l s . Both of t h e s e f e a t u r e s may be improved through d e s i g n enhancement and innovation. The power of t h e module may be i n c r e a s e d i f h i g h e r f u e l t e m p e r a t u r e s (>16OO0C) become a c c e p t a b l e by f u r t h e r f u e l s testi n g and v e r i f i c a t i o n . The c o n n e c t i n g p i p e w i l l r e q u i r e thorough and e x t e n s i v e a n a l y s i s t o show t h a t i t can w i t h s t a n d t h e p o t e n t i a l consequences from seismic e v e n t s . Desirable Characteristics: The use of LEU/Th f u e l l e a d s t o lower f u e l c o n v e r s i o n r a t i o s r e l a t i v e t o t h e u s e of h i g h l y enriched fuels. Modular HTR Research and Development Needs E v a l u a t e d

Within t h e DOE HTR Program, development of a modular HTR Technology Development P l a n u s i n g t h e I n t e g r a t e d Approach i s under way, but r e s u l t s are n o t s u f f i c i e n t l y complete f o r i n c o r p o r a t i o n i n t o NPOVS. However, ORNL has p r e p a r e d a document40 which was p r e s e n t e d t o t h e Subcommittee on Energy Research and P r o d u c t i o n of t h e U.S. House of R e p r e s e n t a t i v e s and which d i s c u s s e d t h e key r e s e a r c h and development areas r e q u i r e d f o r modular HTRs. T h i s s e c t i o n p r e s e n t s R&D needs as e x c e r p t e d from t h i s document w i t h m o d i f i c a t i o n s r e f l e c t i n g a d d i t i o n a l i n f o r m a t i o n o b t a i n e d The key r e s e a r c h and development (R&D) areas are consince that time. sidered i n t h e following c a t e g o r i e s :

3-59 A. B. C.

Base Technology Applied Technology; and Design and Economic S t u d i e s .

I t e m A g e n e r a l l y r e f e r s t o b a s i c i n f o r m a t i o n needed t o e s t a b l i s h t h e f e a s i b i l i t y of t h e r e a c t o r concept and t o materials d a t a needed f o r t h e d e t a i l e d d e s i g n ; i t e m B r e f e r s t o R&D needed t o a s s u r e t h e p r a c t i c a l i t y of components and systems; and i t e m C r e f e r s t o t h e e f f o r t required t o specify the e n t i r e reactor plant i n s u f f i c i e n t d e t a i l t o permit r e l i a b l e economic estimates of p l a n t performance. The key R&D areas which need t o be a d d r e s s e d f o r t h e modular HTR a r e shown below:

3.5.3-1

Base Technology

D e t e r m i n a t i o n of f i s s i o n product r e t e n t i o n of t h e f u e l c o a t i n g s , g r a p h i t e and metal s u r f a c e s of t h e primary system and confinement d u r i n g and subsequent t o extreme a c c i d e n t conditions.

P r o c e s s development f o r f u e l f a b r i c a t i o n and i r r a d i a t i o n t e s t i n g t o o b t a i n u n d e r s t a n d i n g of t h e importance of s p e c i f i c proc e s s i n g p a r a m e t e r s on f u e l performance.

I r r a d i a t i o n t e s t i n g and examination of f u e l s produced i n comm e r c i a l - s c a l e p r o d u c t i o n equipment.

F i s s i o n product b e h a v i o r d u r i n g normal r e a c t o r o p e r a t i o n a s r e l a t e d t o l i f t - o f f and t h e s o u r c e terms under d e p r e s s u r i z a t i o n accidents.

Development of d e t a i l e d materials p r o p e r t i e s under c o n d i t i o n s of c r e e p , f a t i g u e , c o r r o s i o n , and r a d i a t i o n n e c e s s a r y f o r d e s i g n i n g and o p e r a t i n g components.

O b t a i n i n g s t a t i s t i c a l d a t a on g r a p h i t e p r o p e r t i e s as a b a s i s f o r e s t i m a t i n g f u e l element stresses.

C r i t i c a l experiment t e s t i n g of LEU/Th c o r e s , i n c l u d i n g water i n g r e s s r e a c t i v i t y e f f e c t s and t e m p e r a t u r e c o e f f i c i e n t s f o r low e n r i c h e d uranium f u e l w i t h plutonium c o n c e n t r a t i o n s r e p r e s e n t a t i v e of e q u i l i b r i u m burnup.

O b t a i n i n g e x p e r i m e n t a l d a t a t o v a l i d a t e codes a p p l i c a b l e t o t h e p a s s i v e h e a t removal system.

3.5.3.2 1.

Applied Technology Development, v e r i f i c a t i o n , and a p p l i c a t i o n of a n a l y t i c a l t o o l s f o r r e a c t o r d e s i g n , s a f e t y , and r i s k a n a l y s e s , i n c l u d i n g d a t a bases.

3-60 2.

p l a n t s a f e t y and r i s k a n a l y s e s . This r i s k associated with normal o p e r a t i o n and d e s i g n b a s i s a c c i d e n t s needs t o be i n v e s tigated. Also, r i s k a s s o c i a t e d w i t h p o s t u l a t e d e v e n t s beyond d e s i g n b a s i s may need t o be i n v e s t i g a t e d t o c o n f i r m t h a t t h e t o t a l r i s k from such a c c i d e n t s i s small r e l a t i v e t o t h e r i s k from normal p l a n t o p e r a t i o n .

D e t a i l e d r e a c t o r p h y s i c s a n a l y s i s i n c l u d i n g computation of c r o s s s e c t i o n s , power d i s t r i b u t i o n s , t e m p e r a t u r e c o e f f i c i e n t s , and c o n t r o l rod worth under normal c o n d i t i o n s and w i t h water ingress. Also s h i e l d i n g a n a l y s i s t o d e t e r m i n e f l u e n c e f o r t h e d e s i g n of r e a c t o r i n t e r n a l components a t v a r i o u s l o c a t i o n s .

Design and t e s t i n g of r e f u e l i n g equipment t o d e m o n s t r a t e t h a t t h e r e f e r e n c e r e a c t o r c o n c e p t can be r e f u e l e d on t h e assumed schedule.

Design and t e s t i n g of p r o t o t y p i c components and systems such as t h e helium c i r c u l a t o r , c o r e s u p p o r t s t r u c t u r e , and shutdown c o o l i n g h e a t exchanger.

Development of multi-module and h e a t exchange systems.

3.5.3.3

c o n t r o l system,

s e r v i c e sysLems,

Design and Economic S t u d i e s

The d e s i g n of t h e modular HTR p l a n t must be completed i n s u f f i c i e n t d e t a i l t o p e r m i t a f i r m estimate of p l a n t c o s t s , based on f e a t u r e s which l i m i t f u e l t e m p e r a t u r e s under a c c i d e n t c o n d i t i o n s , f a c i l i t a t e shop f a b r i c a t i o n , and r e d u c e balance-of-plant (BOP) c o s t s . Also, a detailed d e t e r m i n a t i o n of o p e r a t i n g and maintenance and f u e l c y c l e c o s t s are required.

3-61 3.6

REFERENCES FOR CHAPTER 3

K. Hannerz (ASEA-ATOM) , Towards I n t r i n s i c a l l y Safe Light Water Rea c t o r s , ORAU/IEA-83-2 (MI-Rev. ( r e s e a r c h memorandum), I n s t i t u t e f o r Energy A n a l y s i s , Oak Ridge A s s o c i a t e d U n i v e r s i t i e s , Oak Ridge, Tenn e s s e e , J u l y 1983.

SECURE P: Design P r o g r e s s I n f o r m a t i o n , ASEA-ATOM, Vasteras, Sweden ( A p r i l 1984). ASEA-ATOM PROPRIETARY.

D. Babala and K. Hannerz, " P r e s s u r i z e d Water Reactor I n h e r e n t Core P r o t e c t i o n by Primary System Thermohydraulics," Nuclear Science and Engineering _ 90(4) . , 4 0 0 4 1 0 (August 1985).

C. Sundqvist and T. Pederson, "PIUS: The Forgiving R e a c t o r , SaEety and O p e r a t i o n a l Aspects," f u l l t e x t of paper p r e s e n t e d a t t h e 1985 Annual Meeting of t h e American Nuclear S o c i e t y (ANS), Boston, M a s s a c h u s e t t s , June 9-14, 1985; ASEA-ATOM, Vasteras, Sweden.

J. D. Duncan and C. D. Sawyer, " C a p i t a l i z i n g on BWR S i m p l i c i t y a t Lower Power R a t i n g s , " SAE T e c h n i c a l Paper S e r i e s 859285 r e p r i n t e d from p. 164, Proceedings of t h e 20th I n t e r s o c i e t y Energy Conversion E n g i n e e r i n g Conference, M i a m i Beach, F l o r i d a , August 18-23, 1985, General E l e c t r i c Company, San J o s e , C a l i f o r n i a .

Lyle C. Wilcox, "U.S. Department of Energy Programs on Cost Reduct i o n , " p r e s e n t e d a t t h e I n s t i t u t e of Applied Energy I n t e r n a t i o n a l Symposium on LMFBR Development, Tokyo , Japan (November 7 , 1984)

Alan E. Walter and A l b e r t B. gamon P r e s s (1981).

Reynolds, F a s t Breeder R e a c t o r s , Per-

1984 Winter Meeting 47,

T r a n s a c t i o n s of ber 11-16 1984).

Consolidated Management O f f i c e f o r t h e ZMFBR of t h e E l e c t r i c Power Research I n s t i t u t e , LSPB Design D e s c r i p t i o n s , Vol. 1, CDS 400-8, Department of Energy, September 1984. APPLIED f o r t h e U.S. TECHNOLOGY.

10.

R. A. L i n d l e y , Large Scale P r o t o t y p e Breeder Cost E f f e c t i v e n e s s C o n s i d e r a t i o n s , C o n s o l i d a t e d Management O f f i c e f o r t h e MFBR of t h e Electric Power Research Institute, August 1984. APPLIED TECHNOLOGY.

t h e ANS

13-16

(Novem-

3-62 11.

C o n s o l i d a t e d Management O f f i c e f o r t h e LMFBR of t h e E l e c t r i c Power Research I n s t i t u t e , LSPB O v e r a l l P l a n t Design S p e c i f i c a t i o n , CDS 100-2, Rev. 7, f o r t h e U.S. Department of Energy and E l e c t r i c Power Research I n s t i t u t e , Washington, D.C., February 1984. APPLIED TECHNOLOGY.

12.

LSPB C o n s t r u c t i b i l i t y R e p o r t , t o be p u b l i s h e d by t h e U.S. ment of Energy. APPLIED TECHNOLOGY.

13.

Modular IMFBR Pool P l a n t F i n a l Report, AI-DOE-13502, Rockwell International, Atomics I n t e r n a t i o n a l , Canoga, Park, California, September 30, 1984. APPLIED TECHNOLOGY.

14.

"Advancing Breeder Reactor Design i n t h e United S t a t e s , " E n g i n e e r i n g I n t e r n a t i o n a l 30(365), 17-20, (February 1985).

15.

T r a n s a c t i o n s of 11-1 6, 1984).

16.

"SUR d i s c u s s i o n s a t ORNL, J a n u a r y 11, 1985," a c o l l e c t i o n of viewgraphs p r e s e n t e d a t t h i s meeting. APPLIED TECHNOLOGY.

17.

Large TXFBR Pool P l a n t , Vol. 1, Design D e s c r i p t i o n , ESG-DOE-13410 Rockwell I n t e r n a t i o n a l , Energy Systems Group, Canoga P a r k , Calif o r n i a , September 1983. APPLIED TECHNOLOGY.

18.

PRISM Semiannual Report, April-September, 1984, XL-897-840073/L3, General Electric Co., Nuclear Systems Technology O p e r a t i o n , Sunnyv a l e , C a l i f o r n i a , October, 1984. APPLIED TECHNOLOGY.

19.

J. S. A r m i j o e t a l . , "General Electric S t r a t e g y f o r Achieving a Low-Cost Liquid Metal Reactor P l a n t , " P r e s e n t e d a t t h e I n s t i t u t e of Applied Energy I n t e r n a t i o n a l Symposium on LMFBR Development, Tokyo, J a p a n , November 7, 1984.

20.

"Advancing Breeder Reactor Design in t h e United S t a t e s , " E n g i n e e r i n g I n t e r n a t i o n a l 30(365), 17-20 ( F e b r u a r y 1985).

21.

PRISM Design Requirements, P r e l i m i n a r y Rev B , 23A3071, General Electric G o . , Nuclear Systems Technology O p e r a t i o n , Sunnyvale, C a l i f o r n i a , October 1984. APPLIED TECHNOLOGY.

22.

I n t e r n a l Correspondence from G. F. Flanagan t o D i s t r i b u t i o n , "Inh e r e n t l y S a f e I M R s , " December 6, 1984.

23.

C l i n c h River Breeder Reactor P l a n t P r o b a b i l i s t i c Risk Assessment, p r e p a r e d f o r t h e U.S. Department of Energy by Technology f o r Energy C o r p o r a t i o n , September 14, 1984.

24.

A. Bayer and K. K o b e r l e i n , " K i s k - O r i e n t e d A n a l y s i s on t h e German P r o t o t y p e F a s t Breeder Reactor SNR-300," Nuclear S a f e t y 2 5 ( 1 ) , 30 (January-Fe bruary 1984).

Depart-

Nuclear

t h e ANS 1984 W i n t e r Meeting

47,

299-300

(November

Nuclear

3-63 the

47, 333-338,

25.

T r a n s a c t i o n s of 11-16, 1984).

26.

"Looking t o t h e F u t u r e with t h e I n t e g r a l F a s t Reactor," Engineering I n t e r n a t i o n a l 30(365), 20 (February 1985).

27.

R. B a l e n t and J. Yedidia, DRAFT, Large Scale P r o t o t y p e Breeder Fuel Department of Energy. Cycle Plan, t o be published by t h e U.S. APPLIED TECHNOLOGY

28.

LSPB Research and Development Requirements, CDS 500-6, U.S. ment of Energy, Washington, D.C., September 1984. TECHNOLOGY.

29.

SAFR Requirements f o r Base Technology Program, 149T1000002, Rockw e l l I n t e r n a t i o n a l Rocketdyne D i v i s i o n , Canoga Park, C a l i f o r n i a , January 1985. APPLIED TECHNOLOGY.

30.

L e t t e r number XL-897-850016 from L. N. Salerns t o Francis X# Gavigan, dated January 11, 1985, "WBS2B0.5- I n i t i a l PRISM R&D Requirements statements." APPLIED TECHNOLOGY.

31.

Letter from J. Ray t o D r . B i l l H a r m s , dated January 31, 1983, w i t h t h e a t t a c h m e n t , "LMFBR S a f e t y Philosophy I s s u e s " , Advanced R e a c t o r s Subcommittee, d r a f t , January 27, 1983.

L e t t e r number T-85-053 from J. D. Mangus t o D. C. Gibbs, d a t e d J u l y 23, 1985, w i t h attachment, "Long L i f e Liquid Metal Core Concept."

33.

U t i l i t y / U s e r s Design Requirements f o r Small High Temperature GasCooled R e a c t o r s , GCRA 84-011, Gas-Cooled Reactor A s s o c i a t e s , San Diego, C a l i f o r n i a , November 1984. APPLIED TECHNOLOGY.

34.

HTGK Program Concept E v a l u a t i o n Plan f o r Small HTGRs, GCRA 84-009, Gas-Cooled Reactor A s s o c i a t e s , San Diego, C a l i f o r n i a , October 31, 1984. APPLIED TECHNOLOGY.

35.

P r e l i m i n a r y Concept E v a l u a t i o n Report, 4 x 250 M W ( t ) HTGR P l a n t Side-by-Side S t e e l Vessel Concept, HTGR-85-005, i s s u e d by Bechtel Group, Inc., e t a l . , f o r Gas-Cooled Reactor A s s o c i a t e s , San Diego, C a l i f o r n i a , February 1985. APPLIED TECHNOLOGY.

36.

FY 1985 HTGR Summary Level Program P l a n , HP-20202-85, Gas-Cooled Reactor A s s o c i a t e s , San Diego, C a l i f o r n i a , October 1984. APPLIED TECHNOLOGY

37.

L i c e n s i n g P l a n f o r t h e Standard HTGR ( D r a f t ) , GCRA 85-001, Group, Inc., e t a l . , J a n u a r y 1985.

ANS

Winter

Meetix

(November Nuclear

DepartAPPLIED

Bechtel

3-64

38.

P r e l i m i n a r y Concept D e s c r i p t i o n Report, 4 x 350 MW(t) HTGR P l a n t Side-by-Side S t e e l Vessel P r i s m a t i c Core Concept, HTGR-85-142, i s s u e d by Bechtel Group Inc. f o r Gas-Cooled Reactor A s s o c i a t e s , San Diego, C a l i f o r n i a , October 1985. APPLIED TECHNOLOGY.

39.

40.

P. R. Kasten, "Statement on an I n h e r e n t l y S a f e High-Temperature Gas-Cooled Reactor Program," p r e s e n t e d t o Subcommittee on Energy Research and P r o d u c t i o n , U.S. House of R e p r e s e n t a t i v e s , M. Lloyd, Chairman, February 7, 1984.

41.

H. R e u t l e r and G. Lohnert, "The Modular High-Temperature Nuclear Technology, 62( l ) , 22-30 ( J u l y 1983). '

R. Kasten e t a l . , Assessment of t h e Thorium Fuel Cycle i n Power R e a c t o r s , ORNL-TM-5565, Oak Ridge N a t i o n a l L a b o r a t o r y , Oak Ridge, Tennessee, J a n u a r y , 1977.

Reactor,

42.

HTR lOO-MW(e) Konzeption; Technik, Termine, Kosten, Hochtemperatur Reaktorbau, Hochtempatur Reaktorbau, Mannheim, F e d e r a l Republic of Germany.

43.

Summary R e p o r t on t h e U t i l i t y I n d u s t r y Que s t i o n a a i r e , GCRA. 84-001, Gas Cooled Reactor A s s o c i a t e s , San Diego, C a l i f o r n i a , February 1984.

44.

P r e l i m i n a r y Concept E v a l u a t i o n Report, 1170 MW(t) HTGR P l a n t PCRV Concept, HTGR-85-004, i s s u e d by Stone & Webster E n g i n e e r i n g Corpora t i o n f o r Gas-Cooled Reactor A s s o c i a t e s , San Diego, C a l i f o r n i a , February 1985. APPLIED TECHNOLOGY.

45.

P r e l i m i n a r y Concept E v a l u a t i o n Report, 1260 MW(t) HTGR P l a n t PCRV Concept, HTGR-85-003, i s s u e d by Stone & Webster E n g i n e e r i n g Corpora t i o n f o r Gas-Cooled Reactor A s s o c i a t e s , San Diego, C a l i f o r n i a , February 1985. APPLIED TECHNOLOGY.

46.

P r e l i m i n a r y Concept E v a l u a t i o n Report, 4 x 250 MW(t) HTGR P l a n t InLine S t e e l Vessel Concept, HTGR-85-006, i s s u e d by B e c h t e l Group, Inc., e t a l . , f o r Gas-Cooled Reactor A s s o c i a t e s , San Diego, Calif o r n i a , February 1985. APPLIED TECHNOLOGY.

47.

An I n t e g r a t e d Approach t o Economical, R e l i a b l e , S a f e Nuclear Power Production, ALO-1-11, Combustion e n g i n e e r i n g , Inc., Windsor, C o n n e c t i c u t , June 1982.

48.

Turbine S e l e c t i o n Trade Study 4 x 250 MW(t) HTR P l a n t SBS/SV Conc e p t , HTGR-85-075, Stone and Webster E n g i n e e r i n g C o r p o r a t i o n f o r Gas-Cooled Reactor A s s o c i a t e s , San Diego, C a l i f o r n i a , J u l y 1985. APPLIED TECHNOLOGY.

ACKNOWLEDGMENTS

The form and scope of t h i s s t u d y n e c e s s i t a t e d t h e involvement of many i n d i v i d u a l s and o r g a n i z a t i o n s . I n f a c t , t h e numbers are so g r e a t and t h e involvement so of t e n i n d i r e c t t h a t complete i n d i v i d u a l r e c o g n i t i o n is next t o impossible. However, t h e c o o p e r a t i o n w a s e x t e n s i v e and effective; t h o s e l i s t e d as a u t h o r s r e c o g n i z e and g r e a t l y a p p r e c i a t e t h i s The i n s t i t u t i o n s and i n d i v i d u a l s who c o n t r i b u t e d through assistance. i n t e r v i e w a n d / o r w r i t t e n r e p o r t s and, i n some cases, t h r o u g h work s p e c i f i c t o t h e s t u d y are as f o l l o w s : R e a c t o r Vendors MEA-ATOM Babcock and Wilcox Combustion E n g i n e e r i n g GA Technologies General E l e c t r i c Company Rockwell I n t e r n a t i o n a l Westinghouse-Advanced Energy Systems D i v i s i o n Architect-Engineers Bechtel S a r g e n t and Lundy S t o n e and Webster United E n g i n e e r s and C o n s t r u c t o r s U t i l i t y Companies and A s s o c i a t i o n s B a l t i m o r e Gas and E l e c t r i c C e n t r a l E l e c t r i c i t y G e n e r a t i n g Board, UK C a r o l i n a Power and L i g h t Duke Power Company E l e c t r i c Power Research I n s t i t u t e E l e c t r i c Power Research I n s t i t u t e C o n s o l i d a t e d Management O f f i c e Gas-Cooled R e a c t o r A s s o c i a t e s Houston Power and L i g h t i n g S o u t h e r n C a l i f o r n i a Edison Wisconsin E l e c t r i c Power Company L a b o r a t o r i e s , I n s t i t u t i o n s , and U n i v e r s i t i e s Argonne N a t i o n a l L a b o r a t o r y Atomic I n d u s t r i a l Forum I n s t i t u t e f o r Energy A n a l y s i s I n t e r n a t i o n a l Atomic Energy Agency Los Alamos N a t i o n a l L a b o r a t o r y M a s s a c h u s e t t s I n s t i t u t e of Technology Nuclear Energy Agency Off i c e of Technology Assessment The U n i v e r s i t y o f Tennessee U.S. Nuclear R e g u l a t o r y Commission 4-1

4-2 I n d i v i d u a l s a t t h e t h r e e c o o p e r a t i n g i n s t i t u t i o n s (ORNL, TVA, and t h e U n i v e r s i t y of Tennessee) who provided a s s i s t a n c e i n c l u d e t h e f o l l o w ing: Oak Ridge N a t i o n a l L a b o r a t o r y Ball Cole Davis Ebersole (consultant) Engel Flanagan L. c. F u l l e r S. Re Greene

S. J. T. E. R e M. J. C. J. R. G. Fa

R. W. 3. 0. A. G. J.

M. H a r r i n g t o n 0. H a r m s E. Kibbe H. K l e p p e r E. Levin Samuels W. Sims

Tennessee V a l l e y A u t h o r i t y D. D. H. J.

T. Bradshaw L. Lambert G. O'Rrien E. Simmons

J. G. S t e w a r t R. E. T a y l o r S. Vigander

The U n i v e r s i t v of Tennessee H.

L. Dodds, Jr.

NPOVS Advisorv Commit tee Members S. B u r s t e i n , Vice-chairman of t h e Board, Wisconsin E l e c t r i c Power Company G. F. D i l w o r t h , D i r e c t o r of E n g i n e e r i n g and T e c h n i c a l S e r v i c e s (DETS), TVA T. S. Elleman, Vice P r e s i d e n t of C o r p o r a t e Nuclear S a f e t y and R e s e a r c h , C a r o l i n a Power and L i g h t Company P. R. Kasten ( S e c r e t a r y ) , T e c h n i c a l D i r e c t o r , Gas-Cooled R e a c t o r Programs, ORNL L. M. Muntzing, Doub and Muntzing, Washington, D.C. D. R. P a t t e r s o n , A s s i s t a n t t o Manager, O f f i c e of E n g i n e e r i n g Design and C o n s t r u c t i o n , TVA W. T. Snyder, Dean, C o l l e g e of E n g i n e e r i n g , The U n i v e r s i t y of Tennessee J. T a y l o r , Vice P r e s i d e n t and D i r e c t o r , Nuclear Power D i v i s i o n , EPRI N . E. Todreas, Department of Nuclear E n g i n e e r i n g , M a s s a c h u s e t t s I n s t i t u t e of Technology

NPOVS Advi s o r v Cornmi t t e e Members ( c o n t i n u e d ) J. T a y l o r , Vice P r e s i d e n t and D i r e c t o r , Nuclear Power D i v i s i o n , EPRI N. E. Todreas, Department of Nuclear E n g i n e e r i n g , M a s s a c h u s e t t s I n s t i t u t e of Technology

APPENDIX A B A S I C OUTLINE FOR NUCLEAR POWER OPTIONS V I A B I L I T Y STUDY F I N A L REPORT

VOLUME I

EXECUTIVE SUMMARY

VOLUME I1

REACTOR CONCEPTS, D E S C R I P T I O N S , AND ASSESSMENTS (see page v )

VOLUME I11

NUCLEAR D I S C I P L I N E T O P I C S ABSTRACT 1. INTRODUCTION 2. CONSTRUCTION 3. ECONOMICS 4. REGULATION 5. SAFETY AND ECONOMIC R I S K 6. NUCLEAR WASTE TRANSPORTATION AND D I S P O S A L 7. MARKET ACCEPTANCE 8. ACKNOWLEDGMENTS

VOLUME I V

APPENDIX A.

INTERVIEW FORMAT FOR THE I S S U E D E F I N I T I O N RESEAKCH AND OUTLINE OF I S S U E S USED FOR THE CASE STUDY INTERVIEWS

APPENDIX B.

TABLES ON THE SAMPLE USED FOR THE I S S U E I D E N T I F I C A T I O N RESEARCH

BIBLIOGRAPHY ABSTRACT 1. INTRODUCTION 2. ORGANIZATION AND RETRIEVAL 3. KEYWORD L I S T 4. KEYWORD INDEX 5. NUCLEAR OPTIONS C I T A T I O N S 6. L I G H T WATER REACTORS C I T A T I O N S 7. L I Q U I D METAL REACTORS C I T A T I O N S 8. HIGH TEMPERATURE REACTORS C I T A T I O N S 9. ACKNOWLEDGMENTS 10. REFERENCES

A- 1

APPENDIX B

THE OUTLOOK FOR ELECTRICITY SUPPLY AND DEMAND*

The p r i n c i p a l d e t e r m i n a n t s of f u t u r e e l e c t r i c i t y demand w i l l probDuring t h e p a s t t e n y e a r s , a b l y be t h e u t i l i t i e s and t h e i r r e g u l a t o r s . u t i l i t i e s have been e v o l v i n g from a s u p p l y i n d u s t r y concerned o n l y w i t h meeting e l e c t r i c i t y r e q u i r e m e n t s t o a s e r v i c e - o r i e n t e d i n d u s t r y conc e r n e d n o t o n l y w i t h t h e s u p p l y of e l e c t r i c i t y but a l s o w i t h c o n t r o l l i n g and s h a p i n g i t s u s e t h r o u g h c o n s e r v a t i o n and l o a d management. Future e l e c t r i c i t y u s e w i l l depend on how f a r t h i s e v o l u t i o n proceeds. The approach t a k e n t o estimate f u t u r e energy use i n v o l v e s a n a n a l y s i s a n d / o r estimate of t h e t r e n d of f a c t o r s t h a t d e t e r m i n e e n e r g y use, such as p o p u l a t i o n , p e r s o n s per household, g r o s s n a t i o n a l p r o d u c t ( G N P ) , s h i f t s i n t h e i n d u s t r i a l p r o d u c t mix, c o n s e r v a t i o n , etc. The p r o j e c t i o n s made h e r e do not r e p r e s e n t a n y t h i n g even a p p r o a c h i n g t h e t e c h nology l i m i t s of energy c o n s e r v a t i o n n o r do t h e y come c l o s e t o t h e economic l i m i t of c o n s e r v a t i o n as p r o j e c t e d by "least c o s t e n e r g y They do depend on c o n t i n u e d e f f i c i e n c y improvements and, strategies. " t o some e x t e n t , on a c o n t i n u a t i o n of u t i l i t i e s ' a v e r s i o n t o i n v e s t m e n t i n new c a p a c i t y , which h a s r e s u l t e d i n c o n s e r v a t i o n and l o a d management programs t o l i m i t demand growth. They probably r e p r e s e n t a narrow band i n t h e upper p a r t of a r a t h e r wide range t h a t c o u l d be expected. Table 8.1 summarizes t h e e s t i m a t e s of t h i s s t u d y f o r growth r a t e s o f e l e c t r i c i t y and n o n e l e c t r i c a l e n e r g y r e q u i r e m e n t s t o t h e y e a r 2000 f o r t h e r e s i d e n t i a l , commercial and i n d u s t r i a l s e c t o r s . The t o t a l growth rate f o r e l e c t r i c i t y i s e s t i m a t e d t o range between 1.8 and 2.3%/ These year and f o r n o n e l e c t r i c a l energy between 0.1 and 0.5%/year. r a t e s r e s u l t i n a growth of primary energy r e q u i r e m e n t s of 0.9 t o 1.4%/ y e a r , which i s e q u i v a l e n t t o u s i n g between 67.3 and 73.9 quads ( e x c l u d i n g t r a n s p o r t a t i o n ) i n t h e y e a r 2000. The t r a n s p o r t a t i o n s e c t o r i s n o t a n a l y z e d i n t h i s s t u d y s i n c e t h i s s e c t o r does n o t use a s i g n i f i c a n t amount of e l e c t r i c i t y and, b a r r i n g a b r e a k t h r o u g h i n b a t t e r y t e c h n o l o g y i s e x p e c t e d t o u s e very l i t t l e e l e c t r i c i t y f o r t h e remainder of t h e century. The r e s i d e n t i a l s e c t o r p r o j e c t i o n s are based on t h e f o l l o w i n g ( 1 ) a p o p u l a t i o n growth r a t e ( a s p r o j e c t e d by t h e Bureau assumptions: of t h e Census) of 0.85%/year between 1980 and 2000); ( 2 ) a household growth r a t e of 1.4%/year, which would c o n t i n u e t h e t r e n d of h o u s e h o l d s growing a t a r a t e a b o u t 60% g r e a t e r t h a n t h e p o p u l a t i o n ; (3) a c o n t i n u a t i o n , a t a modest r a t e , o â&#x201A;Ź t h e t r e n d t o less e n e r g y u s e per household; and ( 4 ) a c o n t i n u a t i o n of t h e t r e n d t o e l e c t r i c s p a c e h e a t i n g .

*Taken from G. Samuels, The Outlook f o r E l e c t r i c i t y Supply and Demand, ORNL/TM-9469, Oak Ridge N a t i o n a l b b o r a t o r y , Oak Ridge, Tennessee, A p r i l 1985.

B-1

B-2

Table B.l. Projected energy use for the residential, commercial, and industrial sectors in the year 2000 1980-2000

Sector

annual growth (%/year)

End use energy ( l O I 5 Btu/year)

Primary energy use ( 1015 Btu/year)

Residential Electricity Nonelectricity

1.50 to 2.00 -1.50 to -1.00

3.30 to 3.64 5.09 to 5.63

11.29 to 12.45 5.09 to 5.63 16.38 to 18.08

Total primary Commercial Electricity Nonelectricity

2.00 to 2.50

2.83 to 3.12 4.09

13.79 to 14.78

Total primary Industrial Electricity Nonelectricity

9.70 to 10.69 4.09

2.00 to 2.50 0.50 to 1.00

4.13 22.99

to 4.56 to 25.39

14.15 to 15.60 22.99 to 25.39 37.14 to 40.99

Total primary U. S . total Electricity Nonelectricity Total primary

1.83 to 2.33 0.06 to 0.50 0.90

to 1.37

10.26 to 11.32 32.17 to 35.11

35.14 to 38.74 32.17 t o 35.11 67.31 to 73.85

B-3 The commercial s e c t o r p r o j e c t i o n s are p r e d i c a t e d on a s u b s t a n t i a l d e c l i n e i n t h e growth r a t e of both s e c t o r a l employment and f l o o r s p a c e - t o an annual rate of 1.5%. E l e c t r i c i t y u s e p e r employee o r p e r u n i t of f l o o r space was assumed t o i n c r e a s e a t a r a t e 0.5 t o 1.0% g r e a t e r t h a n employment o r f l o o r space. The i n d u s t r i a l s e c t o r p r o j e c t i o n s are based on a d e t a i l e d a n a l y s i s of t h e manufacturing i n d u s t r i e s between 1975 and 1980, which examined changes i n t h e energy i n t e n s i t y and o u t p u t of t h e s e i n d u s t r i e s a t t h e four-digit Standard I n d u s t r i a l C l a s s i f i c a t i o n l e v e l . E l e c t r i c i t y use f o r t h e s e i n d u s t r i e s i s p r o j e c t e d t o grow a t a r a t e e q u a l t o about 80% of t h e g r o s s n a t i o n a l product growth r a t e , which i s e x p e c t e d t o be i n t h e range of 2.5 t o 3.0% f o r t h e remainder of t h e c e n t u r y . Although t h e s e estimates are small compared t o most p r o j e c t i o n s of s e v e r a l y e a r s ago, t h e y are i n t h e range of r e c e n t p r o j e c t i o n s and c l o s e t o c u r r e n t " c o n v e n t i o n a l wisdom." An examination of p a s t energy u s e s u g g e s t s t h a t t h e r a p i d growth between 1950 and 1970 w a s s e l f l i m i t i n g and t h a t t h e o i l price shocks of t h e 1970s w e r e a c a t a l y s t t h a t ended t h i s r a p i d growth. The t e c h n o l o g i e s t h a t l e d t o t h i s growth were a v a i l a b l e by 1930. However, t h e Depression and World War I1 delayed t h e i r growth, which r e s u l t e d i n t h e i r impact being compressed i n t o a s h o r t e r time span and t h e r a p i d growth of t h e 1950's and 1960's. The u t i l i t i e s ' p r o j e c t i o n s of f u t u r e demand and t h e i r p l a n s f o r f u t u r e g e n e r a t i n g c a p a c i t y have d e c l i n e d s t e a d i l y over t h e p a s t t e n years. P r o j e c t i o n s f o r peak demand and e l e c t r i c a l energy r e q u i r e m e n t s i n 1992 r e p r e s e n t a 2.25 and 2.61%/year growth from a c t u a l 1980 values. T h e i r p r o j e c t i o n s i n d i c a t e t h a t a v e r a g e r e s e r v e margins f o r t h e Reserve marc o n t i g u o u s United States should be a d e q u a t e through 1992. g i n s are p r o j e c t e d t o d e c l i n e slowly from 41% i n 1982 t o 30% i n 1992. Furthermore, based on u t i l i t y p r o j e c t i o n s , e a c h of t h e n i n e r e g i o n a l rel i a b i l i t y c o u n c i l s w i l l have r e s e r v e margins of a t l e a s t 20% i n 1992. However, t h e adequacy of both r e g i o n a l and U. S. e l e c t r i c i t y s u p p l y depends p r i m a r i l y on t h e v a l i d i t y of t h e d r a s t i c a l l y reduced p r o j e c t i o n s of f u t u r e demand growth and t o a lesser e x t e n t on t h e u t i l i t i e s ' a b i l i t y t o p r o v i d e t h e planned g e n e r a t i n g c a p a c i t y . For example, i f u t i l i t i e s were t o complete o n l y t h o s e u n i t s now under c o n s t r u c t i o n and i f demand grows a s p r o j e c t e d , 1992 r e s e r v e margins would be 22 t o 23%. However, i f demand were t o r e a c h t h a t p r o j e c t e d i n 1980 (a 4% annual growth r a t e ) , c o m p l e t i o n of a l l c u r r e n t l y planned c a p a c i t y by 1992 would prov i d e o n l y a 6% m a r g i n - f a r t o o small t o m a i n t a i n s e r v i c e d u r i n g peak demand p e r i o d s . The s e n s i t i v i t y of r e s e r v e margins t o t h e demand growth r a t e , combined w i t h a l o n g l e a d t i m e r e q u i r e d t o add economical c a p a b i l i t y , h a s l e d t o c o n c e r n s about t h e adequacy of f u t u r e e l e c t r i c i t y supply. At the same time consumer r e s i s t a n c e t o h i g h e r e l e c t r i c i t y p r i c e s and t h e res u l t i n g p r e s s u r e on P u b l i c U t i l i t y Commissions h a s s e r i o u s l y a f f e c t e d t h e u t i l i t i e s ' a b i l i t y t o f i n a n c e t h e c a p a c i t y now being b u i l t . Adding more c a p a c i t y as i n s u r a n c e f o r an unexpected i n c r e a s e i n demand would be d i f f i c u l t t o s e l l t o e i t h e r consumers o r u t i l i t i e s a t t h i s t i m e .

B -4 R e l a t i v e l y low-cost approaches e x i s t f o r l e s s e n i n g t h e p r o b a b i l i t y One approach would be t o a l l o w advance of f u t u r e e l e c t r i c i t y s h o r t a g e s . s i t i n g and p e r m i t t i n g and t h e n "banking" of s i t e s s o t h a t t h e l e a d t i m e would be reduced t o that r e q u i r e d f o r c o n s t r u c t i o n - a b o u t h a l f of t h e c u r r e n t 8- t o 12-year l e a d t i m e . The time f o r which t h e c o n s t r u c t i o n p e r m i t remains v a l i d would have t o be i n c r e a s e d . A second approach would f o l l o w a p a t h now being adopted by a few utilities. T h i s approach would t r e a t c o n s e r v a t i o n and l o a d management a s supply o p t i o n s . U t i l i t i e s would, w i t h t h e a p p r o v a l of r e g u l a t o r s , channel c a p i t a l i n t o t h e most economical o p t i o n t o meet f u t u r e s e r v i c e r e q u i r e m e n t s whether t h i s o p t i o n be i n c r e a s e d c a p a c i t y o r reduced demand. T r e a t i n g demand-reducing o p t i o n s as a supply would permit " c a p a c i t y " a d d i t i o n t o more c l o s e l y match i n c r e a s e s i n demand. Furthermore, t h i s o p t i o n would p r o v i d e r e s u l t s i n less t i m e t h a n t h a t r e q u i r e d f o r adding l a r g e c e n t r a l s t a t i o n s . This s h o r t e r l e a d time would a l s o a l l e v i a t e t h e d e b a t e o v e r i n c l u d i n g c o n s t r u c t i o n work i n p r o g r e s s i n t h e rate base.

REFERENCES [Used i n G. Samuels, 'Ihe Outlook f o r Energy Supply and Demand, ORNL/TM-9469, Oak Ridge N a t i o n a l L a b o r a t o r y , Oak Ridge, Tennessee 37831 ( A p r i l 19851.1

A. P. Sanghvi, "Least Cost Energy S t r a t e g i e s f o r Power l ) , 75-92 (March, 1984). s i o n , " Energy P o l i c y =( R.

U.S.

System Expan-

W i l l i a m s , G. S. D u t t , and H. S. Geller, " F u t u r e Energy Savings i n Housing," Annual Review of Energy 5 269-332 (1983).

Survey of U t i l i t y Load Management and Energy C o n s e r v a t i o n P r o j e c t s , EPKI/EM-1606, Electric Power Research I n s t i t u t e , P a l o A l t o , C a l i f . , November 1980. Conference Proceedings U t i l i t i e s and Energy E f f i c i e n c y ; New Oppo r t u n i t i e s and Risks, October 23-24, 1980, CONF-8010146, , P o r t C h e s t e r , N Y. S t a t e Energy Data Report, 1960 through 1980, Department of Energy, Washington, DC, J u l y 1982.

DOE/EIA-0214(80),

S t a t i s t i c a l A b s t r a c t of t h e United S t a t e s , 1982-83, Commerce, Bureau of t h e Census, Washington, DC.

U.S.

Department of

R e s i d e n t i a l Energy Consumption Survey: Consumption and E x p e n d i t u r e s A p r i l 1980 through March 1981, DOE/EIA-0322/1, U.S. Department of Energy, Washington, DC, September 1982. R e s i d e n t i a l Energy Consumption Survey: Housing C h a r a c t e r i s t i c s 1980, DOE/EIA-0314, U. S. Department of Energy, Washington, DC, J u l y 1982.

B-5 U.S. R e s i d e n t i a l Energy C o n s e r v a t i o n , Volume I, OTA-E-02, O f f i c e of Technology Assessment, Washington, DC, J u l y 1979.

Congress,

1982 Annual Energy Outlook w i t h P r o j e c t i o n s t o 1990, DOE/EIA-0383(92), U.S. Department of Energy, Washington, DC, A p r i l 1983. The F u t u r e of E l e c t r i c Power i n America: Economic Supply f o r Economic Growth, DOE/PE-0045, Department of Energy, Washington, DC, June 1983. J. F. G u s t a f f e r o , "U.S. Energy For t h e Rest of t h e Century," EPKI Workshop P r o c e e d i n g s , P a l o A l t o , C a l i f . , October 25-26, 1983.

Economic Report of t h e P r e s i d e n t ,

February 1982.

N o n r e s i d e n t i a l B u i l d i n g s Energy Consumption Survey: F u e l Characteri s t i c s and C o n s e r v a t i o n P r a c t i c e s , DOE/EIA-0278, U.S. Department of Energy, Washington, DC, June 1981. N o n r e s i d e n t i a l B u i l d i n g s Energy Consumption Survey: B u i l d i n g C h a r a c t e r DOE/ELA-O246, U.S. Department of Energy, Washington, DC, March 1981.

istics,

N o n r e s i d e n t i a l B u i l d i n g s Energy Consumption Survey: 1979 Consumption and E x p e n d i t u r e s , P a r t 1: N a t u r a l Gas and E l e c t r i c i t y , DOE/EIA-0318/1, U.S. Department of Energy, Washington, DC, March 1983. F u e l s and E l e c t r i c Energy Con1980 Annual Survey of Manufacturers: sumed, I n d u s t r y Groups and I n d u s t r i e s , M80(AS)-4.1, Bureau of t h e Census, U. S . Department of Commerce, Washington, UC, August 1982. Monthly Energy Review, DOE/EIA-0035(93/08), Washington, DC, August 1983.

U.S.

Department of Energy,

Survey of C u r r e n t B u s i n e s s , g ( 7 ) , Bureau of Economic A n a l y s i s , Department of Commerce, Washington, DC, J u l y 1982.

U.S.

Survey of C u r r e n t B u s i n e s s , 6 3 ( 7 ) , Bureau of Economic Analyses, Department of Commerce, Washington, DC, J u l y 1983.

U.S.

G. Samuels, D. P. Vogt, and D. M. Evans, S h i f t s i n Product Mix Versus Energy I n t e n s i t y as Determinants of Energy Consumption i n t h e Manufact u r i n g S e c t o r , p r e s e n t e d a t Electric Power Research I n s t i t u t e Workshop on F o r e c a s t i n g I n d u s t r i a l S t r u c t u r a l Change i n t h e U. S.A., October 2526, 1983. U.S. I n d u s t r y Outlook 1977 w i t h P r o j e c t i o n s t o 1985, U.S. Commerce, Washington, DC, J a n u a r y 1977.

Department of

1979 U.S. I n d u s t r i a l Outlook w i t h P r o j e c t i o n s t o 1983 f o r 200 Ind u s t r i e s , I n d u s t r y and Trade A d m i n i s t r a t i o n , U.S. Department of Commerce, Washington, DC, J a n u a r y 1979.

B-6 1983 U.S. I n d u s t r i a l Outlook f o r 250 I n d u s t r i e s w i t h P r o j e c t i o n s f o r Bureau of I n d u s t r i a l Economies, U.S. Department of Commerce, Washington, DC, J a n u a r y 1983.

-1987 '

I n d u s t r i a l Energy Use, Assessment, June 1983.

OTA-E-198,

Congress,

U.S.

O f f i c e of

Technology

C. C. Burwell, Glassmaking: A Case Study of t h e Form Value of Elect r i c i t y Used i n Manufacturing, ORAU/IEA-82-9(M), I n s t i t u t e f o r Energy A n a l y s i s , Oak Ridge A s s o c i a t e d U n i v e r s i t i e s , Oak Ridge, TN, J u l y 1982.

Burwell, I n d u s t r i a l E l e c t r i f i c a t i o n : C u r r e n t Trends, ORAU/IEA-834(M), I n s t i t u t e f o r Energy A n a l y s i s , Oak Ridge A s s o c i a t e d U n i v e r s i t i e s , Oak Ridge, TN, February 1983. 6 . C.

E l e c t r i c Power Supply and Demand 1983-1992, North American E l e c t r i c Rel i a b i l i t y C o u n c i l , P r i n c e t o n , N J , J u l y 1983. Energy P r o j e c t i o n s t o t h e Year 2010, DOE/PE-0029/2, Energy, Washington, DC, October 1983.

U.S.

Department of

G. Samuels, Op t i a n s f o r E l e c t r i c i t y U s e and Management d u r i n g a Petroleum S h o r t a g e , ORNL-5918, Oak Ridge N a t i o n a l L a b o r a t o r y , Oak Ridge, TN, J a n u a r y 1983.

GAD S-Gener a t ing Ava i 1a b i 1i t y Data Sy s t e m , Equipment Ava i 1a b i 1i t y Report 1972-1981. North American E l e c t r i c R e l i a b i l i t y Council. P r i n c e t o n , N J .

Monthly Energy Review, DOE/EIA-0035/80, Washington, DC, J u l y 1980.

U.S.

Department

Energy,

1 3 t h Annual Review of O v e r a l l R e l i a b i l i t y and Adequacy of Bulk Power Supply i n t h e E l e c t r i c U t i l i t y Systems of North America, North American E l e c t r i c R e l i a b i l i t y C o u n c i l , P r i n c e t o n , N J , August 1983. S. Kichen and L. P i t t e l , (December 5 , 1983).

"Utilities:

"Around t h e S t a t e L e g i s l a t u r e s , " 1984).

Are t h e Good T i m e s Over?," Forbes

Modern M a t u r i t y (December 198+January

APPENDIX C

DISCUSSION OF CONCEPTS NOT INCLUDED FOR ASSESSMENT

Many r e a c t o r c o n c e p t s were proposed and c o n s i d e r e d f o r assessment i n NPOVS. A l i s t of t h o s e c o n c e p t s t h a t were not s e l e c t e d f o r d e t a i l e d assessment f o l l o w s . The e x c l u s i o n of c o n c e p t s w a s based p r i m a r i l y on t h e ground r u l e s a1 though o t h e r c o n s i d e r a t i o n s c o n t r i b u t e d t o t h e select i o n process. E x p l a n a t i o n s are i n c l u d e d w i t h e a c h concept. LWR APWR -

The Advanced PWR by Westinghouse i s c o n s i d e r e d s u f f i c i e n t l y developed t o be a v a i l a b l e now; hence, t h e r e i s no m e r i t i n NPOVS assessment of t h e concept as a f u t u r e v i a b l e option. Furthermore, s a f e t y r e l i e s s u b s t a n t i a l l y on c o n v e n t i o n a l and e n g i n e e r e d systems. ABWR - The Advanced BWR by General E l e c t r i c i s c o n s i d e r e d s u f f i c i e n t l y developed t o be a v a i l a b l e now; hence, t h e r e i s no merit i n NPOVS assessment of t h e concept as a f u t u r e v i a b l e option. Some of t h e Advanced BWR f e a t u r e s are ref l e c t e d i n t h e small BWR and, t h u s , a r e being c o n s i d e r e d S a f e t y r e l i e s s u b s t a n t i a l l y on c o n v e n t i o n a l i n NPOVS. engineered s y st e m s CNSS - The c o n s o l i d a t e d Nuclear Steam Supply System concept by B&W i s based on a v a i l a b l e t e c h n o l o g y and i n c l u d e d l i t t l e emphasis on p a s s i v e s a f e t y . Steam-Cooled LWR - T h i s "Schultz-Edlund" concept h a s no c u r r e n t act i v e vendor promoting it. As a r e s u l t , i t i s judged t h a t t h e concept w i l l n o t be a v a i l a b l e as a demonstrated o p t i o n by 2010. W-NUPACK 600 The small [600 MW(e)] barge-mounted p l a n t o f f e r s numerous c o s t a d v a n t a g e s based on t h e maximum use of f a c t o r y q u a l i t y f a b r i c a t i o n , s t a n d a r d i z a t i o n , and modularization. Westinghouse proposes marketing t h e p l a n t w i t h a n NRC f i n a l d e s i g n a p p r o v a l s o t h a t u t i l i t i e s would f a c e p r i m a r i l y o n l y t h e s i t e s u i t a b i l i t y issues i n l i c e n s i n g . NUPACK w i l l probably i n c o r p o r a t e o t h e r d e s i g n s i m p l i f i c a t i o n and advanced f u e l c y c l e f e a t u r e s of t h e APWR. Although NUPACK r e l i e s s i g n i f i c a n t l y on p a s s i v e s a f e t y i t i s more t r a d i t i o n a l i n i t s approach, p r i m a r i l y employing engineered s a f e t y features. CE-Realistic A l t e r n a t i v e Reactor T h i s concept c a l l s f o r a s e l f p r e s s u r i z i n g , s i n g l e v e s s e l , r e a c t o r - s t e a m g e n e r a t o r modIt i s s i m i l a r i n many ways t o t h e CNSS, but u s e s ule. n a t u r a l c i r c u l a t i o n f o r powered o p e r a t i o n and does n o t r e l y on t h e use of c o n t r o l r o d s o r s o l u b l e p o i s o n f o r cont r o l d u r i n g burnup. P r e s s u r e feedback i s t h e c o n t r o l mechanism under powered o p e r a t i o n . Design s i m p l i f i c a t i o n has been employed t o l i m i t t h e e f f e c t s of many a n t i c i p a t e d t r a n s i e n t s and t r a d i t i o n a l d e s i g n b a s i s e v e n t s f o r convent i o n a l LWRs, but t h e u l t i m a t e s a f e t y r e s p o n s e would s t i l l r e l y on t h e i n t e r v e n t i o n of e n g i n e e r e d s a f e t y f e a t u r e s .

C-l

c-2 HWR -

CANDU

LMR Large

The Canadian heavy water r e a c t o r s have s e r v e d t h e i r domest i c needs w e l l and have been deployed i n s e v e r a l o t h e r countries. Thus i t i s a v i a b l e o p t i o n , but t h e r e i s no U.S. sponsor and t h e concept depends on e n g i n e e r e d s a f e t y f e a t u r e s f o r decay h e a t removal. A principal rational c o s t advantage d e r i v e s from i t s u s e of n a t u r a l uranium. However, t h i s advantage i s l o s t when enrichment e x i s t s , as i n t h e United S t a t e s . A smaller r e a c t o r , CANDU 300 h a s been announced r e c e n t l y which i s t o have improved f e a t u r e s f o r s a f e t y and r e l i a b i l i t y , but i t r e l i e s on e n g i n e e r e d s a f e t y systems and does not meet a p a s s i v e s a f e t y c r i teria.

Pool - T h i s c o l l e c t i v e term a p p l i e s t o s e v e r a l c o n c e p t s t h a t are being demonstrated i n o t h e r c o u n t r i e s and some conThe c o n c e p t s reviewed c e p t s s t u d i e d i n t h e United S t a t e s . have no a c t i v e U.S. vendors promoting them and, hence, are n o t c o n s i d e r e d a v a i l a b l e by 2010. However, t h e EPKI-COMO program r e c e n t l y t u r n e d a t t e n t i o n t o a l a r g e pool d e s i g n . Large Loop - The l a r g e l o o p LMR c o n c e p t s ( o t h e r t h a n t h e LSPB) have no a c t i v e proponent t h a t would accomplish a d e m o n s t r a t i o n of t h e concept by 2010. These c o n c e p t s are d e s i g n e d w i t h a c t i v e , d i v e r s e , and redundant s a f e t y and do not emphasize passive safety. The economic approach t o t h e l a r g e l o o p LMR i s based on t h e need f o r t h e b r e e d e r and t h u s do n o t meet t h e economic ground r u l e w i t h p r e s e n t and near-term fuel prices. w-Pool - The Westinghouse pool LMR concept w a s one of t h e cont e n d e r s f o r t h e DOE s u p p o r t of advanced c o n c e p t s . Origi n a l l y r e l y i n g on an i n t e g r a t e d f u e l c y c l e w i t h o n - s i t e r e p r o c e s s i n g and r e f a b r i c a t i o n , i t w a s l a t e r changed n o t t o r e q u i r e t h e i n t e g r a l f u e l cycle. Not enough informat i o n and d e t a i l have been a v a i l a b l e t o NPOVS t o i n c l u d e t h i s concept i n t h e d e t a i l e d assessment. Hybrid - The Stone & Webster concept i s based on two v e s s e l s , one f o r t h e c o r e and one f o r components, connected by pipes. Not enough i n f o r m a t i o n i s a v a i l a b l e t o NPOVS t o i n c l u d e t h i s concept i n t h e d e t a i l e d assessment. Thermal LMR - The moderated c o r e , cooled by l i q u i d metal, h a s no c u r r e n t sponsor. It i s judged as n o t a v a i l a b l e by t h e y e a r 2010, and not enough i n f o r m a t i o n i s a v a i l a b l e f o r i t t o be c o n s i d e r e d i n an assessment. There i s l i t t l e i n f o r mation about i t s p r e s e n t economic p o t e n t i a l or i t s p a s s i v e safety features. IFR The I n t e g r a l F a s t Reactor, based on m e t a l l i c f u e l , i n t e g r a t e d p y r o m e t a l l u r g i c a l r e p r o c e s s i n g and on-si te f a b r i c a t i o n , w i t h t h e emphasis on m e t a l l i c f u e l , i s promoted by ANL. The r e a c t o r p o r t i o n of t h e concept was n o t developed i n s u f f i c i e n t d e t a i l f o r assessment. The l a c k of an a c t i v e vendor c o n t r i b u t e d t o t h e concept not being judged

c-3 a v a i l a b l e f o r deployment by 2010. However, f e a t u r e s of t h i s c o n c e p t have been i n c o r p o r a t e d i n t h e SAFR and PRISM concepts t h a t a r e included i n t h i s report. Also, an a n a l y s i s of t h e f u e l c y c l e i s p r e s e n t e d i n Appendix E. GCR -

MSR -

HTR

GCFR

AGR

T h i s c o l l e c t i v e name a p p l i e s t o v a r i o u s v e r s i o n s of t h e High-Temperature Gas-Cooled Reactors. Of t h e s e , t h e " Side-by-Side" p r i s m a t i c f u e l c o n c e p t was chosen f o r assessment. Other c o n c e p t s were n o t examined i n d e t a i l b e c a u s e t h e side-by-side modular c o n c e p t had been s e l e c t e d However, f o r d e t a i l e d s t u d y w i t h i n t h e U.S. HTR Program. e x p e r i e n c e from t h e p e b b l e bed c o n c e p t now o p e r a t i n g i n two German d e m o n s t r a t i o n u n i t s w a s u t i l i z e d i n t h e study. The 860-MWe l a r g e HTR h a s been i n c l u d e d as an appended r e f e r e n c e s i n c e much of t h e HTR t e c h n o l o g y d e v e l opment has been r e l a t e d t o t h i s c o n c e p t and because i t has s i g n i f i c a n t p a s s i v e f e a t u r e s , see Appendix F. The Gas-Cooled F a s t R e a c t o r h a s no c u r r e n t a c t i v e proponent and hence i s judged n o t t o be a v a i l a b l e by t h e y e a r 2010. Also, t h e a v a i l a b l e d e s i g n s f o r a GCFR do n o t i n corporate s i g n i f i c a n t passive safety features. This B r i t i s h d e s i g n e d and o p e r a t e d GCR h a s r e a c h e d a p o i n t of v i r t u a l s t a n d a r d i z a t i o n i n t h e Heysham I1 and T o r n e s s s i n g l e - c a v i t y PCRV d e s i g n s . These p l a n t s s h a r e t h e l a r g e c a p i t a l i n v e s t m e n t r e q u i r e m e n t s of t h e l a r g e HTR but a t a lower power r a t i n g due t o lower g a s t e m p e r a t u r e s f o r t h e carbon d i o x i d e c o o l a n t . Therefore, competitive c a p i t a l c o s t s i n a U.S. market would be very d o u b t f u l . Recent t e s t s a t Hinkley P o i n t B have shown a d e q u a t e p a s s i v e c o o l i n g of t h e p r e s s u r i z e d c o r e t o t h e PCRV c o n c r e t e w i t h o u t damaging f u e l o r l i n e r ; however, t h e d e p r e s s u r i z e d c o r e c o o l i n g does r e q u i r e f o r c e d c o n v e c t i o n . As a t F o r t St. V r a i n , l i n e r c o o l i n g of t h e PCRV must be m a i n t a i n e d t o ret a i n any r e l e a s e d f i s s i o n p r o d u c t s r e s u l t i n g from a dep r e s s u r i z e d l o s s of normal h e a t s i n k .

All Molten S a l t R e a c t o r v e r s i o n s are e x c l u d e d from de-

MSR

t a i l e d a s s e s s m e n t s i n c e h a v i n g no c u r r e n t a c t i v e prop o n e n t , t h e y c a n n o t become a v a i l a b l e by 2010. Designs f o r molten s a l t c o n c e p t s d a t e back many y e a r s . Passive s a f e t y i s n o t a d v e r t i s e d , a l t h o u g h many p a s s i v e f e a t u r e s a r e e v i d e n t and some can be c o n s i d e r e d " i n h e r e n t " t o l i q u i d f u e l systems. Economic estimates t h a t were made a r e a l l obsol e t e and cannot be used f o r e v a l u a t i n g economic v i a b i l i t y . Other

A few o t h e r c o n c e p t s ( " e x o t i c a " ) such as t h e f l u i d i z e d bed r e a c t o r were b r i e f l y c o n s i d e r e d and r e j e c t e d f o r l a c k of d e s i g n i n f o r m a t i o n , l a c k of a s p o n s o r , and i n s u f f i c i e n t other information.

APPENDIX D R&D GOALS AND SPECIFIC REQUIREMENTS FOR L I Q U I D METAL REACTOR (LMR) CONCEPTS

Table D.l i s a d e t a i l e d p r e s e n t a t i o n of R&D needs judged by t h e LMK d e s i g n e r s as e s s e n t i a l o r i m p o r t a n t t o t h e s u c c e s s of t h e i r s p e c i f i c power p l a n t designs.1-3 S i m i l a r needs have been combined. The t a b l e a l s o i n d i c a t e s which R&D needs might a p p l y t o o t h e r r e a c t o r c o n c e p t s and It should be p r o v i d e s j u s t i f i c a t i o n f o r i n c l u s i o n of each need. emphasized t h a t Table D. 1 i n c l u d e s only t h o s e R&D t a s k s r e q u i r e d t o complete a d e s i g n t o meet r e q u i r e m e n t s and s p e c i f i c a t i o n s . S e v e r a l c h a l l e n g e s were i d e n t i f i e d f o r t h e LMR i n d u s t r y i n t h e sect i o n d e a l i n g w i t h a d v a n t a g e s and d i s a d v a n t a g e s of t h e concepts. Conside r a t i o n i s g i v e n h e r e t o g e n e r a l R&D g o a l s which could h e l p meet t h e s e challenges. However, t o p u t t h i s d i s c u s s i o n i n p e r s p e c t i v e , two a s s e r t i o n s a r e made and p o t e n t i a l g o a l s formulated. F i r s t , t h e LMR h a s a long-term p o t e n t i a l f o r breeding t o extend f u e l r e s o u r c e s . Therefore, one g o a l should be t o m a i n t a i n t h e c a p a b i l i t y t o meet t h i s c h a l l e n g e . W e a l s o assert t h a t t h e worldwide n u c l e a r program w i l l be s u s t a i n e d through t h e NPOVS t i m e frame, t h a t a s i g n i f i c a n t market f o r LYR c o n v e r t e r s a n d / o r b r e e d e r s e v e n t u a l l y w i l l develop, and t h a t U.S. i n d u s t r y w i l l seek a s h a r e of t h i s market. Thus, a second g o a l should be t o s u s t a i n a c o m p e t i t i v e LMti i n d u s t r i a l p o t e n t i a l i n t h e United S t a t e s f o r a s i g n i f i c a n t range i n growth r a t e s of domestic and f o r e i g n power needs. A c o m p e t i t i v e i n d u s t r y would have an a d e q u a t e number of p r o p e r l y t r a i n e d t e c h n o l o g i s t s , up-to-date and a p p r o p r i a t e f a c i l i t i e s , and a c o m p e t i t i v e d e s i g n t o sell. These g e n e r a l R&D needs have been o r g a n i z e d i n t h e form of a h i e r a r c h y i n Table D.2 where t h e s e g o a l s and programs have been c a t e g o r i z e d w i t h i n t h r e e major headings. This t a b l e , though p r e l i m i n a r y , p r o v i d e s a framework f o r e v a l u a t i n g t h e importance of v a r i o u s R&D a c t i v i t i e s . For example, one could d e t e r m i n e t h e relat i v e importance of t h e l i s t e d and augmented K&D t a s k s under t h e s c e n a r i o of low, modest, and high growth rates f o r t h e u t i l i t y i n d u s t r y . Prel i m i n a r y a s s e s s m e n t s i n d i c a t e t h a t t h e l i s t of R&D t a s k s i s n o t s e n s i t i v e t o t h e s c h e d u l e ; only t h e r e l a t i v e importance of t h e R&D t a s k s was s c e n a r i o dependent.

D- 1

Table D.l.

S p e c i f i c r e s e a r c h a n d d e v e l o p m e n t n e e d s i d e n t i f i e d f o r t h e LMR c o n c e p t

LMR c o n c e p t s f o r which t h e K & D n e e d s was i d e n t i f i e d (*) o r a p p l i c a b l e (X)

R e s e a r c h and Development ( R & D ) n e e d s i d e n t i f i e d by t h e d e s i g n e r as e s s e n t i a l o r important

LSPB

SAFK

PRISM

Other concepts f o r which t h e R&D may b e a p p l i c a b l e

I,hX

HTR

J u s t i f i c a t i o n f o r t h e R&D n e e d Demonstrates low c o s t

Supports licensing

Increases Investor o r public confidence

SAFETY-RELATED REQUIREMENTS Advanced Core D e s i g n

E v a l u a t e c o r e f e a t u r e s which c a n a s s u r e a benign c o r e r e s p o n s e t o c o r e d i s r u p t i v e accident i n i t i a t o r s . D e m o n s t r a t e a l o w - c o s t and r e l i a b l e approach f o r a s e l f - a c t u a t e d shutdown s y s t e m . P r o v i d e e x p e r i m e n t a L v e r i f i c a t i o n s of t h i s c o n c e p t needed f o r licensing discussions. Develop h i g h t e m p e r a t u r e , wide r a n g e , f i s s i o n c h a n n e l s and i o n chambers f o r power m o n i t o r i n g a t i n - v e s s e l l o c a t i o n s , and h i g h s e n s i t i v i t y s o u r c e - r a n g e f i s s i o n channels f o r s t a r t u p monitoring. Perform experiments t o demonstrate t h e e f f e c t i v e n e s s of B4C as a n i n - v e s s e l s h i e l d and v e r i f y s h i e l d design. P e r f o r m d e t a i l e d s h i e l d i n g and f l u x c a l c u l a t i o n s needed f o r t h e d e s i g n . Perform c o r e c r i t i c a l experiments a t ZPPR t o p r o v i d e n u c l e a r p a r a m e t e r s and d e t e c t o r r e q u i r e m e n t s , and t e s t l o a d i n g sequences f o r a l l cores considered. P r o v i d e a n a l y t i c a l v e r i f i c a t i o n of b e n i g n r e s p o n s e of t h e c o r e t o a l l design basis accidents.

U I

Table D.l.

S p e c i f i c r e s e a r c h a n d d e v e l o p m e n t n e e d s i d e n t i f i e d f o r t h e LMR c o n c e p t ( c o n t i n u e d )

LMR c o n c e p t s f o r which t h e R&D n e e d s was i d e n t i f i e d (*) o r a p p l i c a b l e (X)

R e s e a r c h and Development (R&D) n e e d s i d e n t i f i e d by t h e d e s i g n e r as e s s e n t i a l o r i m p o r t a n t

LSPB

SAFR

PRISM

Develop w t h o d o l o g i e s f o r a s s i g n i n g p r o b a b i l i t i e s f o r accident sequences a s s o c i a t e d w i t h core d i s r u p t i v e accidents. These p r o b a b i l i t i e s a r e t o be u s e d i n E v e n t Trees and PRA s t u d i e s f o r c o r e r e s p o n s e s and s t r u c t u r a l responses.

E v a l u a t e t h e r e a c t o r s y s t e m and o t h e r system responses t o earthquakes t o d e t e r m i n e seismic e v e n t c a t e g o r i e s , evaluate safety s y s t e m r e l i a b i l i t i e s , a n d p r o v i d e i n p u t s t o PRA s t u d i e s .

D e v e l o p n e c e s s a r y i n p u t and p e r f o r m a n a l y s e s needed t o q u a n t i f y c o n t a i n m e n t r e s p o n s e e v e n t trees f o r a c c i d e n t sequences.

P e r f o r m s e i s m i c a n a l y s i s and tests t o p r e d i c t t h e r e s p o n s e of t h e c o r e a n d r e a c t o r assembly t o a s e i s m i c e v e n t . V a l i d a t e t h e code used through experimental t e s t s . Collect and a p p l y d a t a on j o i n t f a i l u r e p r o b a b i l i t i e s o f . key components f o r u s e i n r e l i a b i l i t y and r i s k a s s e s s m e n t calculations.

Other concepts f o r which t h e R&D may be a p p l i c a b l e

LWR

HTR

J u s t i f i c a t i o n f o r t h e R&D n e e d Demonstrates low c o s t

Supports licensing

I n c r e a s e s I n v e s t o r or public confidence

Table D.l.

S p e c i f i c r e s e a r c h and d e v e l o p m e n t n e e d s i d e n t i f i e d f o r t h e lMR c o n c e p t ( c o n t i n u e d )

LMR c o n c e p t s f o r which t h e RbD n e e d s was i d e n t i f i e d (*) o r a p p l i c a b l e (X)

R e s e a r c h and Development (R&D) n e e d s i d e n t i f i e d by t h e d e s i g n e r a s e s s e n t i a l OK i m p o r t a n t Develop and v e r i f y a 3-D c o u p l e d thermoh y d r a u l i c , mechanical, n e u t r o n i c , trans i e n t code u s e d t o s u p p o r t t h e d e s i g n of i n h e r e n t l y s a f e r e a c t o r c o r e s . Develop a t h e r m a l - h y d r a u l i c s c o r e t o c h a r a c t e r i z e t e m p e r a t u r e and f l o w f i e l d s i n large cores.

LSPB

SAFR

PRISM

LWR

HTR

J u s t i f i c a t i o n f o r t h e RdD n e e d Demonstrates low c o s t

P e r f o r m t e s t i n g and a n a l y s i s t o q u a n t i f y c o r r o s i o n and f i s s i o n p r o d u c t m i g r a t i o n and p l a t e o u t i n a s e a l e d v e s s e l w i t h o u t cleanup systems.

Supports licensing

P r o v i d e f r i c t i o n a n d wear c o r r e l a t i o n s t o s u p p o r t i n n o v a t i v e c o r e holddown designs.

D e v e l o p and v a l i d a t e a n a n a l y s i s code t h a t can c a l c u l a t e d e f o r m a t i o n s of v a r i o u s c o r e components due t o c r e e p a n d s w e l l i n g and c a l c u l a t e m e c h a n i c a l l o a d s t h e r e b y produced.

Other concepts f o r which t h e R 6 D may be a p p l i c a b l e

Increases Investor o r public confidence

Shutdown Heat Removal P e r f o r m e x p e r i m e n t a l s i m u l a t i o n s of DRACS, RVACS, and RACS s y s t e m s t o e v a l u a t e t h e i r passive design f e a t u r e s , demonstrate t h e i r o p e r a t i n g p r i n c i p l e s , and o p t i m i z e t h e i r performance. Review 1984 t e s t s of t h e CRBRP NDHX s y s t e m and u n d e r s t a n d u n c e r t a i n t i e s i n t h e p e r f o r m a n c e of t h i s s y s t e m a t low a i r f l o w c o n d i t i o n s . P e r f o r m 3-D t h e r m a l - h y d r a u l i c a n a l y s i s of t h e KVACs performance. P e r f o m tests of a s s o c i a t e d flow c o n t r o l devices.

T a b l e D.l.

S p e c i f i c r e s e a r c h a n d d e v e l o p m e n t n e e d s i d e n t i f i e d f o r t h e &R

LMR c o n c e p t s f o r which t h e R & D n e e d s was i d e n t i f i e d (*) or a p p l i c a b l e (X) R e s e a r c h and Development (R&D) n e e d s i d e n t i f i e d by t h e d e s i g n e r as e s s e n t i a l o r i m p o r t a n t

LSPB

SAFR

PRISM

Other concepts f o r which t h e R&D may be a p p l i c a b l e

LWR

HTR

concept (continued)

J u s t i f i c a t i o n f o r t h e R&D need Demonstrates low c o s t

Supports, licensing

D e t e r m i n e and i n c r e a s e , i f n e c e s s a r y , t h e immunity of t h e d e c a y h e a t r e m o v a l f u n c t i o n t o sodium f i r e s .

Perform tests t o v e r i f y design margins f o r c r e e p of b e l l o w s i n p i p i n g s y s t e m s a t e l e v a t e d temperature.

D e s i g n a n d e v a l u a t e t h e p e r f o r m a n c e of a metal (U-Pu-Zr) c o r e . T e s t f u e l assemblies i n t o demonstrate performance f o r n o r m a l and o f f - n o r m a l conditions.

E v a l u a t e and d e m o n s t r a t e t h e r e p r o c e s s i n g and r e f a b r i c a t i o n of m e t a l fuel.

Validate s a f e t y claims associated with metal f u e l .

Increases Investor o r public confidence X

FUEL- RELATED REQU I KEMENTS I n t e g r a l Fast Reactor X

Long-life core P e r f o r m e x t e n d e d b u r n u p tests a t FFTF of c o r e materials, and b l a n k e t , and c o n t r o l assemblies. Demonstrate RBCB p e r f o r m a n c e a t EBR-11.

T a b l e D.l.

S p e c i f i c r e s e a r c h and d e v e l o p m e n t n e e d s i d e n t i f i e d f o r t h e J A R c o n c e p t ( c o n t i n u e d )

LMR c o n c e p t s f o r which t h e R&D n e e d s was i d e n t i f i e d (*) OK a p p l i c a b l e ( X ) R e s e a r c h and Development (RLD) n e e d s i d e n t i f i e d by t h e d e s i g n e r as e s s e n t i a l OK i m p o r t a n t ~

LSPB

SAFR

PKISM

Other concepts f o r which t h e R&D may be a p p l i c a b l e

LWR

HTR

J u s t i f i c a t i o n f o r t h e R&D n e e d DelnOnStKateS low c o s t

Supports licensing

Increases Investor o r public confidence

~~~~

P e r f o r m c h a r a c t e r i z a t i o n t e s t of c l a d d i n g a n d d u c t materials a t FFTF t o d e t e r m i n e i r r a d i a t i o n e f i e c t s a t prototypic temperatures. P e r f o r m t r a n s i e n t t e s t s of h i g h burnup f u e l p i n s t o d e m o n s t r a t e r e l i a b l e performance under upset conditions.

P m

Automated F u e l F a b r i c a t i o n E v a l u a t e a p p r o a c h e s and p r o v i d e c o n c e p t u a l d e s i g n of f a b r i c a t i o n p r o c e s s e s and e q u i p m e n t s y s t e m r e q u i r e men t s

SYSTEM-AND COMPONENT-KELATED REQUIREMENTS P l a n t Experience U t i l i z e operating reactor experience and d a t a t o e v a l u a t e s h i e l d i n g p r e d i c t i o n s , c o r e performance p r e d i c t i o n s , and f l u x m o n i t o r r e s p o n s e s , and v e r i f y under-sodium-viewing d e v i c e p e r f o r m a n c e . E s t a b l i s h a n d t e s t methods t o d e t e c t , l o c a t e , and f i x steam g e n e r a t o r l e a k s . F a b r i c a t e a p r o t o t y p i c d e t e c t i o n and l o c a t i o n system.

T a b l e D. 1.

S p e c i f i c r e s e a r c h a n d d e v e l o p m e n t n e e d s i d e n t i f i e d f o r t h e LMR c o n c e p t ( c o n t i n u e d )

~~~

LMR c o n c e p t s f o r which t h e R6D n e e d s was i d e n t i f i e d (*) o r a p p l i c a b l e (X)

R e s e a r c h and Development (R&D) n e e d s i d e n t i f i e d by t h e d e s i g n e r as e s s e n t i a l or i m p o r t a n t Improve t h e d e s i g n of c o n v e n t i o n a l c o l d t r a p s o r d e v e l o p new d e s i g n s which a r e more r e l i a b l e , t h e r e b y i m p r o v i n g p l a n t availability. P e r f o r m a n a l y s e s and t e s t i n g a s s o c i a t e d w i t h t h e PHTS s i p h o n b r e a k e r t o d e t e r m i n e i t s position, size, erosionlcorrosion r e s i s t a n c e and r e l i a b i l i t y .

LSPB

SAFR

PRISM

Other concepts f o r which t h e R6D may be a p p l i c a b l e

LWR

HTR

J u s t i f i c a t i o n f o r t h e R&D n e e d Demonstrates low c o s t

Supports licensing

Increases Investor o r public confidence

Advanced P l a n t Technology P e r f o r m h y d r a u l i c tests, u s i n g a s c a l e model, of t h e t e m p e r a t u r e and f l u i d f l o w of t h e plenum, IHX, v e s s e l w a l l , a n d r e a c t o r v e s s e l u n d e r normal power a n d n a t u r a l c i r c u l a t i o n conditions. Evaluate various candidate mterials a s i n - v e s s e l i n s u l a t i o n between t h e c l o s u r e h e a d and sodium s u r f a c e , w i t h p a r t i c u l a r a t t e n t i o n g i v e n t o French d e s i g n s .

S t u d y t h e e f f e c t i v e n e s s of r e d a n as a t h e r m a l b a r r i e r and p r e s s u r e s e a l .

D e v e l o p a n a p p r o a c h f o r a u t o m a t i n g maint e n a n c e f u n c t i o n s f o r a multi-module reactor site. I n v e s t i g a t e methods f o r v a l i d a t i o n a n d v e r i f i c a t i o n of s o f t w a r e u s e d i n r e a c t o r c o n t r o l and p r o t e c t i o n systems.

P v

Table D.l.

S p e c i f i c r e s e a r c h a n d d e v e l o p m e n t n e e d s i d e n t i f i e d f o r t h e LMR c o n c e p t ( c o n t i n u e d )

LMR c o n c e p t s f o r which t h e R&D needs w a s i d e n t i f i e d (*) o r a p p l i c a b l e (X)

R e s e a r c h and Development (RbD) n e e d s i d e n t i f i e d by t h e d e s i g n e r a s e s s e n t i a l o r important

LSPB

SAFR

PKISM

Conduct steam g e n e r a t o r e n d u r a n c e t e s t s t o d e m o n s t r a t e long-term i n t e g r i t y . Investigate other options t o simplify t h e o v e r a l l system. I n v e s t i g a t e t h e p e r f o r m a n c e of b o o s t e r t u b e s i n s t e a m generators. Recommend o r r e f e r e n c e s y s t e m and i d e n t i f y n e c e s s a r y key f e a t u r e s tests.

Verify t h a t e x i s t i n g inspection techn i q u e s f o r SGs meet code r e q u i r e m e n t s a n d d e v e l o p new t e c h n i q u e s which m i g h t be used a t e l e v a t e d t e m p e r a t u r e s and i n t h e p r e s e n c e of sodium.

Improve c o m p u t e r code p r e d i c t i o n s of SG p e r f o r m a n c e u n d e r low sodium f l o w conditions.

I n v e s t i g a t e a d v a n c e d i n s t r u m e n t a t i o n and c o n t r o l s t r e s s automation, d i s t r i b u t e d c o n t r o l m u l t i p l e x i n g , improve measurement s e n s o r s and s y s t e m s , s i m p l i f i e d m a i n t e n a n c e , u s e of a r t i f i c i a l i n t e l l i g e n c e , o p e r a t o r a i d s , and human e n g i n e e r i n g .

Other concepts f o r which t h e R&D may b e a p p l i c a b l e

LWR

HTK

J u s t i f i c a t i o n f o r t h e K&D n e e d

Demonstrates low c o s t

Supports licensing

Increases Investor o r public confidence X

Steam G e n e r a t o r P e r f o r m a n c e

Improved Mat e r i a l s O b t a i n code a p p r o v a l f o r advanced m a t e r i a l s and s i m p l i f y o r improve code tules t o r c o n v e n t i o n i a l m a t e r i a l s .

Table D.1.

Specific research and development needs identified for the ZMR concept (continued)

LMR concepts for which the R&D needs was identified ( * ) or applicable (X) Research and Development (R&D) needs identified by the designer as essential or important Perform thermal striping tests for various candidate materials for upper internal designs.

LSPB

SAFR

Evaluate materials which could enhance radiative heat transfer associated with decay heat removal systems. Evaluate purification methods for primary sodium and cover gas in a sealed, vessel during normal operation, and during refueling. Verify the capability of an under sodium viewing system to satisfy in-service inspection requirements and refueling inspection requirements. Perfom component testing and obtain information from the British and French concerning location of failed fuel using a sodium sipper. Develop channel mission monitor

a high sensitivity, fission with remote signal transcapabilities for use as a of initial core loadings.

PRISM

Other concepts for which the R&D may be applicable

LWR X

HTR

Justification for the R6D need Demonstrates Supports Increases Investor or low cost licensing public confidence X

Table D.l.

S p e c i f i c r e s e a r c h a n d d e v e l o p m e n t n e e d s i d e n t i f i e d f o r t h e LMR c o n c e p t ( c o n t i n u e d )

LMR c o n c e p t s f o r which t h e R6D n e e d s was i d e n t i f i e d (*) O K a p p l i c a b l e (X) K e s e a r c h and Development ( W D ) n e e d s i d e n t i f i e d by the d e s i g n e r as e s s e n t i a l o r i m p o r t a n t

LSPB

SAFR

PRISM

Develop a d v a n c e d pool-pumps s u c h as a compact, s e l f - c o o l e d e l e c t r o m a g n e t i c pump a n d a s h r o u d e d i n d u c e r pump.

T e s t c o n t r o l rod d r i v e - l i n e designs which p r o v i d e i n h e r e n t n e g a t i v e r e a c t i v i t y i n r e s p o n s e t o core excursions.

I n c r e a s e c o n f i d e n c e i n t h e u s e of f l e x i b l e j o i n t s i n piping system t h r o u g h t h e i r t e s t i n g a t EBR-11.

D e t e r m i n e f l o w d i s t r i b u t i o n s and i n v e s t i g a t e v i b r a t i o n s f o r IHXs t h r o u g h tests of p h y s i c a l models.

Other concepts f o r which t h e K6D may b e a p p l i c a b l e

LWR

HTR

J u s t i f i c a t i o n f o r t h e R&D need Demonstrates low c o s t

Supports licensing

I n c r e a s e s I n v e s t o r OK public confidence

Advanced Sodium Component F e a t u r e T e s t s

ti t-

D e v e l o p a c o n c e p t u a l d e s i g n of an i n n o v a t i v e r e f u e l i n g and maint e n a n c e s y s t e m , and d e m o n s t r a t e key f e a t u r e s by t e s t i n g . D e m o n s t r a t e t h e f u n c t i o n i n g of t h e core support systems through tests using a n engineering s c a l e model. Develop methods f o r under-sodium, i n - s e r v i c e i n s p e c t i o n of h e a t exchanges.

Table D.l.

Specific research and development needs identified for the LMR concept (continued)

LMR concepts for which the R&D needs was identified ( * ) or applicable (X) Research and Development (R&D) needs identified by the designer as essential or important Perform tests of the reliability of the bearings and seals for the rotating plug of the closure head. Perform test to demonstrate the performance under design and abnormal conditions of centrifuga1 pumps, inducer pumps, and electromagnetic pumps. Perform tests to verify that primary and secondary control rod systems satisfy design requirements.

LSPB

SAFR PRISM

Other concepts for which the R&D may be applicable

LWR

HTR

Justification for the R6D need Demonstrates Supports low cost licensing

U I

*One or more of the needs of the associated list was specifically identified for this design. 'One

Increases Investor or public confidence

or more of the needs of the associated list would be applicable for this design.

Table D.2.

A hierarchy of R&D tasks to keep the LMR/Breeder option as healthy and competitive as possible considering a realistic range in future nuclear energy usage ~

Maintain an adequate work force of technologists and appropriate up-to-date facilities

Continue to improve LMR designs so that the concepts available will be competitive

Support R&D that increases the design options available for new LMR concepts and significantly improves the technology

Complete and demonstrate technical solutions to long-established design challenges

Materials research for higher operating temperatures and improved efficiencies Steam generator designs to eliminate sodium-water reactions (double-wall concepts) or provide instrumentation for more accurate and reliable detection

Demonstrate passive safety against core-di sruptive accidents Establish the plant size and configurations which have the potential for lowest power costs Demonstrate cost competitive offsite and/or on-site reprocessing and refabrication

Continue to solve institutional problems and improve the marketability of LMR concepts ~

-~ ~

provide monetary incentives for utilities and industry to build LMR demonstration plants and facilities (for example, license them as R&D facilities Encourage and support R&D that increases consumption of electrical energy within the guidelines of national policy (for example, support storage battery research to make electric cars attractive) Decrease the complexity and shorten the time required for licensing (for example, one step licensing process) Increase utility involvement in LMR technology through personnel exchanges, joint research, etc.

Improved instrumentation and control to incorporate advances in automation, artificial intelligence, digital control etc.

Demonstrate simpler, passive, decay heat removal concepts

Complement non-U.S. R6D and commercialization activities so information exchange with other countires will be mutually beneficial

Advanced oxide fuel designs for higher burnup, and metal fuels for safety and reprocessing advantages

Strive for a significantly better reactor design with convincing advantages in cost, public acceptance, licensability, etc.

If required, obtain support for LMR technologists and R&D facilities from closely related areas such as defense, space research, etc., so that their skills will be maintained

Improved core designs for a once-through cycle so that reprocessing is not necessary for cost competitiveness

Produce, test, and qualify whole plant designs andfor components such as steam generators, pumps, etc., which can be sold to non-U.S. markets

Support university research to maintain a continuous supply of technologists

Support standardization of design for improved licensability

tl I P N

D-13 REFERENCES FOR APPENDIX D

LSPB Research and Development Requirements, CDS 500-6, U.S. ment of Energy, D.C., September 1984. Washington, TECHNOLOGY

SAFR Requirements f o r Base Technology Program, 149T1000002, Rockwell I n t e r n a t i o n a l Rocketdyne D i v i s i o n , Canoga P a r k , C a l i f o r n i a , January 1985. APPLIED TECHNOLOGY.

L e t t e r number XL-897-850016 Gavigan, d a t e d January 11, Requirements Statements."

from 1985,

DepartAPPLIED

L. N. S a l e r n o t o F r a n c i s X. "WBS2B0.5 I n i t i a l PRISM R&D

APP,ENDIX E L I Q U I D METAL REACTOR (LMR) FUEL REPROCESSINGREFABRICATION EVALUATION

J. T. B e l l and D. C. Hampson

This evaluation ms developed t o compare IMR f u e l recycle systems f o r oxide and metal f u e l s . An adequate data base wa8 not then available, particularly f o r the metal fueZ of the Integral Fast Reactor (IFR). An extensive p r o g m of study is now i n progress a t Argonne National Laboratory t o develop a metal f u e l system f o r the LMR and thus f i l l t h i s void. Although the following e v a l u a t i m i s preliminary, it i l l u s t r a t e s the questions that must be resolved t o arrive a t a f i n a l comparison of the f u e l systems. The conclusions should be viewed qualit a t i v e l y since the quantitative r e s u l t s are subject t o revision as new data are developed by the Argonne study. However, our principal concerns f o r Argonne's e s t i m t e s of the amount of research and development required and for the project costs, both of which are lower than our analysis indicates, have not been alleviated by work published t o date. On the other hand, the s c i e n t i f i c quality of the process research reported appears t o be excellent. T h i s e v a l u a t i o n c l a s s i f i e s f a s t r e a c t o r f u e l s as e i t h e r o x i d e o r metal. Reprocessing of oxide f u e l s i s c o n s i d e r e d o n l y w i t h t h e Purex p r o c e s s , and t h e r e s u l t s are based p r i m a r i l y on ORNL e x p e r i e n c e over t h r e e decades. Metal f u e l s r e p r o c e s s i n g i s c o n s i d e r e d f o r an Argonne N a t i o n a l Laboratory (ANL)-developed p y r o p r o c e s s t h a t i n c l u d e s molten s a l t and e l e c t r o c h e m i c a l t e c h n i q u e s . The d i s c u s s i o n of Purex p r o c e s s i n g w i l l r e l a t e d i r e c t l y t o any f a s t r e a c t o r concept w i t h mixed-oxide (MOX) f u e l , w h i l e t h e d i s c u s s i o n of metal f u e l r e p r o c e s s i n g r e l a t e s d i r e c t l y t o t h e Argonne I n t e g r a l F a s t R e a c t o r (IFR). The t o t a l r e a c t o r o u t p u t f o r each concept i s assumed t o be 1300 MW(e). Most s t u d i e s and programs f o r oxide f u e l r e p r o c e s s i n g have been f o r s u b s t a n t i a l l y l a r g e r p l a n t s . The small s i z e h e r e i s chosen t o match t h e IFR concept. These two f u e l r e p r o c e s s i n g schemes w i l l be compared, and t h e r e s u l t i n g a n a l y s i s s h o u l d be g e n e r i c a l l y a p p l i c a b l e t o o t h e r r e a c t o r c o n c e p t s when m e t a l and o x i d e f u e l s are c o n s i d e r e d . The metal f u e l c o u l d be p r o c e s s e d by t h e Purex r o u t e w i t h minor modifications. However, t h i s would d i s c a r d one of t h e prime b e n e f i t s of t h e p y r o p r o c e s s , which i s t h a t t h e f u e l remains e s s e n t i a l l y i n a metal s t a t e which i s amenable t o r e f a b r i c a t i o n s t e p s developed f o r t h e metal fuels. The metal f u e l r e f a b r i c a t i o n p r o c e s s i s somewhat less complic a t e d t h a n t h e p e l l e t p r e s s i n g p r o c e s s e n v i s i o n e d f o r t h e MOX f u e l s .

A c o s t e s t i m a t e f o r t h e Purex r e p r o c e s s i n g of o x i d e f u e l s w i l l be more a c c u r a t e t h a n t h a t f o r metal f u e l s because t h e Purex p r o c e s s , i n c l u d i n g management of i t s wastes, h a s a l r e a d y been developed t o t h e conc e p t u a l d e s i g n s t a g e s f o r t h e Hot E n g i n e e r i n g F a c i l i t y (HEF) i n 1978 and t h e Breeder Reprocessing E n g i n e e r i n g Test (BRET) i n 1984. The fuseds a l t e l e c t r o - r e f i n i n g p r o c e s s (FSER) proposed f o r r e p r o c e s s i n g metal

E-1

E- 2 f u e l s is i n t h e development and p r o o f - o f - p r i n c i p l e s t a g e s . Although t h e FSER p r o c e s s i s less developed, o u r a n a l y s i s w i l l assume t h a t t h i s process f o r metal f u e l s i s v a l i d , i n p r i n c i p l e , and t h a t d e s i g n of equipment f o r a Hot Experiment P l a n t (HEP) could b e -g i n i n 1986 f o r t h e o x i d e f u e l and i n 1989 f o r t h e metal f u e l . It i s assumed t h a t an HEP f o r e i t h e r p r o c e s s i s r e q u i r e d t o p r o v i d e d e s i g n d a t a f o r a commercial demonstration r e p r o c e s s i n g plant. T h i s e v a l u a t i o n a p p l i e s t o t h e 1985-2005 t i m e frame and i s based on a commercial d e m o n s t r a t i o n r e a c t o r i n 2005. The s c h e d u l e would r e q u i r e a f u e l r e p r o c e s s i n g d e m o n s t r a t i o n p l a n t about 3 y e a r s l a t e r . To meet t h e 2005 g o a l , we have assumed t h a t c e r t a i n major f a c i l i t i e s are a v a i l a b l e now. The F a s t Flux T e s t F a c i l i t y (FFTF) a t Hanford would be used f o r i r r a d i a t i n g o x i d e f u e l s , and t h e Fuels and Materials Examination F a c i l i t y (FMEF), a l s o a t Hanford, would be used f o r a n o x i d e f u e l HEP. The Experimental Breeder Reactor No. 2 (EBR 11) and a s s o c i a t e d F u e l Cycle F a c i l i t y (FCF) a t Idaho F a l l s would be used f o r i r r a d i a t i n g metal f u e l s and f o r a molten s a l t - e l e c t r o c h e m i c a l HEP, r e s p e c t i v e l y . I n b o t h cases, i t i s assumed t h a t the e x i s t i n g f a c i l i t i e s (FMEF and FCF) can be modified and equipped t o p r o v i d e t h e f u n c t i o n s of t h e HEP. Each HEP would be used t o develop and d e m o n s t r a t e t h e p r o o f - o f - p r i n c i p l e of t h e r e s p e c t i v e p r o c e s s and would r e c e i v e i r r a d i a t e d f u e l s s u p p l i e d by It t h e a s s o c i a t e d r e a c t o r (FFTF f o r MOX, and EBR 11 f o r metal f u e l s ) . should be noted t h a t t h e FFTF does not have b l a n k e t e l e m e n t s , which would be p r e s e n t i n a d e m o n s t r a t i o n f a s t b r e e d e r r e a c t o r (FBR). The proof-of-principle d e m o n s t r a t i o n s would p r o v i d e the t e c h n i c a l informaIt i s t i o n n e c e s s a r y f o r t h e d e s i g n of a d e m o n s t r a t i o n f a c i l i t y . assumed t h a t t h e s e HEPs would c o n t r i b u t e s u f f i c i e n t l y t o d e s i g n i n f o r m a t i o n t o j u s t i f y a second d e m o n s t r a t i o n p l a n t . However, t h e l a t t e r may commercial p l a n t . Without t h e s e f a c i l i t i e s , i t i s be a f i r s t - o f - a - k i n d u n l i k e l y t h a t e i t h e r p r o c e s s could be commercially demonstrated i n t h e NPOVS t i m e frame.

E. 1 Schedules f o r Development of Commercial Demonstration

The 2OOG-2010 p e r i o d h a s been s e l e c t e d as a f e a s i b l e o b j e c t i v e f o r d e m o n s t r a t i o n of a s e l e c t e d new power r e a c t o r and t h e a s s o c i a t e d f u e l cycle. Although t h e n e c e s s a r y t i m e f o r r e p r o c e s s i n g would be 3 t o 5 y e a r s a f t e r t h e d e m o n s t r a t i o n r e a c t o r goes on l i n e , a f u l l y developed f u e l c y c l e would be e s s e n t i a l t o a d o p t i o n of t h e I F R concept. To e s t a b l i s h s c h e d u l e s f o r d e v e l o p i n g t h e r e p r o c e s s i n g / r e f a b r i c a t i o n systems f o r o x i d e and metal f u e l s , i t w a s presumed t h a t a n e x i s t i n g f a c i l i t y could be modified f o r s p e c i f i c needs of e a c h p r o c e s s . This f u r t h e r i m p l i e s t h a t t h e u s e of t h e FCF f o r metal f u e l s o r t h e FMEF f o r o x i d e f u e l s would be a d e q u a t e t o p r o v i d e p r o o f - o f - p r i n c i p l e i n f o r m a t i o n f o r e i t h e r f u e l cycle. However, u s e of t h e s e e x i s t i n g f a c i l i t i e s would not p r o v i d e t h e hard-schedule f i n a n c i a l d a t a f o r c o n s t r u c t i o n t h a t a r e r e q u i r e d f o r t h e commercial phase; such d a t a would be a product of t h e d e m o n s t r a t i o n phase.

E-3 The major d i f f e r e n c e between t h e two s c h e d u l e s i s t h a t t h e metal f u e l r e p r o c e s s i n g must be i n i t i a t e d w i t h a p r o c e s s / w a s t e development p h a s e , w h i l e t h i s work i s n o t needed f o r t h e o x i d e f u e l r e p r o c e s s i n g program. Adequate development work has been done on t h e o x i d e program t o p e r m i t immediate i n i t i a t i o n of t h e d e s i g n a c t i v i t i e s . The metal f u e l r e c y c l e program would be d i v i d e d i n t o t h r e e components: p r o c e s s / w a s t e development proof-of-principle 0

r u n s i n t h e FCF, and

d e s i g n and c o n s t r u c t i o n of l o c a t i o n t o be determined.

a demonstration f u e l cycle plant at a

The o x i d e f u e l r e c y c l e program would be d i v i d e d i n t o two major component s: 0

proof-of-principle

d e s i g n and c o n s t r u c t i o n of l o c a t i o n t o be determined.

Three c o n s t r a i n t s metal f u e l processing:

r u n s i n t h e FMEF, and

have

a demonstration f u e l cycle plant at a

been

incorporated

into

the

schedule

for

The p r o c e s s must be proven on a l a b o r a t o r y scale p r i o r t o d e s i g n of t h e m o d i f i c a t i o n s f o r t h e FCF.

C o l d - t e s t i n g of t h e p r o c e s s must be s u c c e s s f u l l y completed i n t h e FCF p r i o r t o s t a r t of d e s i g n f o r t h e d e m o n s t r a t i o n p l a n t .

H o t - t e s t i n g of b o t h t h e s e p a r a t i o n p r o c e s s and t h e waste p r o c e s s s h o u l d be completed p r i o r t o s t a r t of c o n s t r u c t i o n of t h e demons t r a t i o n plant.

The one c o n s t r a i n t t h a t was deemed n e c e s s a r y f o r o x i d e f u e l p r o c e s s i n g w a s t h a t t h e i n t e g r a t e d h o t - t e s t i n g s h o u l d be completed p r i o r t o s t a r t of c o n s t r u c t i o n of t h e d e m o n s t r a t i o n p l a n t . R e f a b r i c a t i o n of b o t h f u e l s must be i n c l u d e d i n t h e r e s p e c t i v e HEP, and p r q o f - t e s t i n g should be comp l e t e d b e f o r e i n i t i a l c o n s t r u c t i o n of t h e d e m o n s t r a t i o n f a c i l i t y . The two s c h e d u l e s are based on a commitment t o conduct t h e v a r i o u s a c t i v i t i e s w i t h i n t h e t i m e frames shown. T h i s i s c r i t i c a l , and d e l a y s i n any phases of t h e program would be r e f l e c t e d i n c o r r e s p o n d i n g d e l a y s i n s u b s e q u e n t phases. As can be s e e n i n t h e t a b l e a t t h e end of t h i s s e c t i o n , t h e r e i s l i t t l e room f o r s l i p p a g e i n e i t h e r f u e l c y c l e schedule. These are t h e most o p t i m i s t i c f e a s i b l e s c h e d u l e s and are g i v e n o n l y t o show t h a t a 2005 o b j e c t i v e could be a c h i e v e d . These s c h e d u l e s can be accomplished o n l y i f t h e f o l l o w i n g a r e done:

E- 4 1.

The m e t a l - f u e l s c h e d u l e i s s t a r t e d immediately.

Experimental r e a c t o r space f o r f u e l t e s t i n g is dedicated t o t h i s effort.

E x i s t i n g f a c i l i t i e s are a v a i l a b l e and d e d i c a t e d (There i s no t i m e f o r c o n s t r u c t i o n of new HEPs.)

Waste management i s developed p a r a l l e l t o t h e chemical processing. ( T h i s w i l l r e q u i r e an a d d i t i o n a l e f f o r t i n t h e metal f u e l s program s i n c e l i t t l e work has been done f o r t h i s waste t o d a t e . The n e c e s s a r y development may e x t e n d p a s t t h e 1997 d a t e . )

F u e l f a b r i c a t i o n must be developed s i m u l t a n e o u s l y w i t h t h e c h e m i c a l reprocessing.

Plutonium must be a v a i l a b l e f o r f u e l t e s t i n g and f o r i r r a d i a t i o n i n o r d e r t o have a d e q u a t e s p e n t f u e l a v a i l a b l e f o r e i t h e r HEP i n t h e 1991 t i m e frame.

the

HEPs.

Summary Schedule f o r Development

Laboratory experimentation s t a r t e d Complete l a b o r a t o r y e x p e r i m e n t a t i o n S t a r t equipment d e s i g n f o r FCF o r FMEF S t a r t m o d i f i c a t i o n s t o FCF o r FMEF I n s t a l l equipment i n FCF o r FMEF Complete bas e experiment a1 program S t a r t design demonstration plant S t a r t c o n s t r u c t i o n of d e m o n s t r a t i o n p l a n t S t a r t d e s i g n of d e m o n s t r a t i o n equipment I n s t a l l d e m o n s t r a t i o n equipment Complete c o n s t r u c t i o n S t a r t operating t h e demonstration plant

*NR i n d i c a t e s s t e p s n o t r e q u i r e d . be advanced one y e a r .

E.2

Thus,

Metal

Oxide

1985 1987 1988 1989 1990 1997 1994 1998 1996 2000 2002 2004

NR* NR* 1988 1989 1991 1993 1989 1993 199 1 1996 1997 1999

t h e o x i d e s c h e d u l e could

The Two P r o c e s s e s

The f l o w s h e e t f o r pyrochemical p r o c e s s i n g of metal f u e l 1 and a n e q u i v a l e n t Purex f l o w s h e e t f o r o x i d e f u e l s 2 were e v a l u a t e d . The blockdiagram f l o w s h e e t s d e s c r i b e d below are based on t h e c o n c e p t u a l d e s i g n e f f o r t s f o r commercial-scale f u e l c y c l e f a c i l i t i e s t o s e r v e 1200 t o 1400 MW(e) e l e c t r i c i t y g e n e r a t i n g c a p a c i t y ( n i n e PRISM modules o r f o u r SAFR power p a k s ) . R e f a b r i c a t i o n f l o w s h e e t s f o l l o w Argonne i n f o r m a t i o n f o r metal f u e l s and t h e mechanical-blending p e l l e t forming p r o c e s s f o r oxide fuels.

E-5 E.2.1

The Pyrochemical P r o c e s s f o r Metal F u e l s

The p r e s e n t IFR concept (1985) i n c l u d e s a r e a c t o r - g e n e r a t o r s y s t e m o p e r a t i n g i n a f u e l break-even c o n v e r t e r mode but c o n s t r u c t e d w i t h t h e p o t e n t i a l of o p e r a t i n g i n a f u e l b r e e d e r mode. For t h i s a n a l y s i s , mult i p l e r e a c t o r s are c o n s i d e r e d i n a 1300-MW(e) u n i t w i t h a s s o c i a t e d f u e l cycle f a c i l i t i e s . A f u e l burnup of 11% i s proposed w i t h o u t an a x i a l blanket. The break-even o p e r a t i o n r e q u i r e s a r e p r o c e s s i n g system w i t h a t h r o u g h p u t of 7.5 t o n n e s / y e a r ( t / a ) ( 3 0 k g / d ) of c o r e f u e l and 8 t / a ( 3 3 kg/d) of combined i n t e r n a l and r a d i a l b l a n k e t f u e l . 3 However, i f the r e a c t o r has p o t e n t i a l f o r f u t u r e f u e l breeding, t h e reprocessing f a c i l i t y must be i n i t i a l l y c o n s t r u c t e d t o accommodate t h e b r e e d e r s y s tem. The p r e v i o u s l y proposed IFR b r e e d e r r e q u i r e d r e p r o c e s s i n g c a p a c i t i e s of 7.5 and 18 t / a (30 and 72 kg/d) of c o r e and b l a n k e t f u e l , respectively. This a n a l y s i s w i l l c o n s i d e r o n l y t h e h i g h e r - c a p a c i t y r e q u i r e m e n t s f o r t h e b r e e d e r mode. Again, no a x i a l b l a n k e t i s assumed. A block-diagram f l o w s h e e t f o r r e p r o c e s s i n g metal f u e l i s shown i n A s p e c i a l committee a p p o i n t e d by t h e U n i v e r s i t y of Chicago Fig. E.l. has reviewed t h e c h e m i s t r y proposed f o r t h e r e p r o c e s s i n g of metal f u e l ; f u r t h e r d i s c u s s i o n i s n o t p r e s e n t e d here. The c o r e and t h e b l a n k e t f u e l i n i t i a l l y must be p r o c e s s e d s e p a r a t e l y , and t h e plutonium from t h e b l a n k e t f u e l i s added t o t h e c o r e f u e l . The b l a n k e t f u e l i s d i s assembled, chopped, and d i s s o l v e d from t h e c l a d d i n g by an e l e c t r o d i s s o l u t i o n process. The f u e l d i s s o l v e d i n cadmium i s c o n t a c t e d w i t h a s a l t m i x t u r e t o o x i d i z e t h e plutonium t o PuC13, which t r a n s f e r s i n t o t h e salt solution. Some of t h e uranium and most of t h e f i s s i o n p r o d u c t s w i l l a l s o be o x i d i z e d and d i s s o l v e d i n t o t h e s a l t . Noble metal f i s s i o n p r o d u c t s w i l l remain predominantly w i t h t h e u n o x i d i z e d uranium. After t h i s h a l i d e slagging, the s a l t s o l u t i o n is t r a n s f e r r e d t o the process l i n e f o r t h e c o r e f u e l and i s c o p r o c e s s e d through t h e e l e c t r o l y s i s scheme. Some problems w i t h t h e h a l i d e s l a g g i n g p r o c e s s i n c l u d e waste h a n d l i n g and c o n t r o l of t h e metal o x i d a t i o n . The plutonium i s o x i d i z e d by adding u c l 3 t o t h e s a l t s o l u t i o n . The amount r e q u i r e d w i l l depend on t h e amount of f i s s i o n p r o d u c t s t h a t o x i d i z e b e f o r e t h e plutonium o x i d i z e s . The added uranium a l s o r e p l a c e s t h a t consumed i n t h e b l a n k e t .

A s shown i n block form i n Fig. E.l, t h e f u e l b u n d l e s are d i s assembled and t h e i n d i v i d u a l c o r e f u e l p i n s are p u n c t u r e d t o release g a s e o u s f i s s i o n p r o d u c t s and t h e n chopped i n t o s h o r t segments. I f an a x i a l b l a n k e t had been i n c l u d e d , t h a t material would be m e c h a n i c a l l y s e p a r a t e d and t r a n s f e r r e d t o t h e d e c l a d d i n g and t h e h a l i d e s l a g g i n g process f o r b l a n k e t f u e l . The chopped c o r e f u e l i s d i s s o l v e d i n t o cadmium; t h e c l a d d i n g does n o t d i s s o l v e . The s a l t s o l u t i o n from t h e h a l i d e s l a g g i n g of t h e b l a n k e t f u e l i s added t o t h e cadmium. T h i s r e s u l t s i n a two-phase l i q u i d system - a molten s a l t phase i n c o n t a c t w i t h a m o l t e n metal phase. Also, t h e c l a d d i n g and t h e u n d i s s o l v e d f u e l make up a s o l i d phase i n t h e cadmium l i q u i d metal. In electrorefining, the m e t a l phase i s used as t h e anode, and a c a t h o d e i s p l a c e d i n t h e s a l t phase. The PuC13 i s e l e c t r o - r e d u c e d t o plutonium from t h e s a l t phase o n t o t h e cathode. Plutonium i s t r a n s f e r r e d from t h e m e t a l t o t h e s a l t phase by The same e l e c t r o l y s i s mechanism o x i d a t i o n a t t h e anode t o PuC13.

E-6 ORNL DWG 8 5 - 4 9 2

CLAD WASTE

3 DECLADDING STEP

A I

SODIUM REMOVAL

ISALT

The block diagram flowsheet for pyro-electro-chemical Figure E.l. reprocessing fast reactor metal fuel. Numbered blocks indicate space requirements in the containment, and multiple numbers per block indicate duplicate equipment. The decladding step, block 3 , has not been defined but is thought to be feasible by an electrochemical process. Any such process will likely require at least three additional space requirements. The letters a, b, c, d indicate a sequence of steps following the electro-refining. During startup of the reactor with enriched uranium, the core uranium cannot be isotopically diluted with blanket uranium, and the blanket fuel may need to pass two times (or more) through the halide slagging step to reduce to uranium content.

E- 7

a p p l i e s t o t h e r e d u c t i o n of u C l 3 t o uranium and of Z r C l s t o zirconium, Control and t h e p r o d u c t i s a m i x t u r e o r an a l l o y of t h e t h r e e metals. of t h e r e d u c i n g p o t e n t i a l can p a r t i a l l y s e g r e g a t e t h e metals on t h e cathode.

E.2.2

The Purex P r o c e s s f o r Oxide F u e l s

The assumed LMR d e s i g n , as f o r t h e metal f u e l e d system, i s a 1300-MW(e) f a c i l i t y . The c o r e and b l a n k e t f u e l s can be p r o c e s s e d i n t h e same equipment. A r e p r o c e s s i n g f a c i l i t y on t h e s i t e f o r t h i s 1300-MW(e) complex would r e q u i r e a c a p a c i t y of 35 t / a (8 t / a of c o r e and 27 t / a of b l a n k e t f u e l ) o r about 140 kg/d a t 2 5 0 d / a . The Purex p r o c e s s f o r r e p r o c e s s i n g o x i d e f u e l s i s diagrammed i n Both t h e c o r e and t h e Fig. E.2 and h a s been p r e v i o u s l y d e s c r i b e d . 2 b l a n k e t f u e l s are p r o c e s s e d through t h e same equipment. The head-end o p e r a t i o n i n v o l v e s d i s a s s e m b l y of t h e f u e l bundles and chopping of f u e l i n t o 1-in. segments. D i s s o l u t i o n i n c l u d e s t r a n s f e r of f u e l from t h e c l a d d i n g i n t o n i t r i c a c i d and removal of c l a d d i n g h u l l s from t h e process. I n t h e f e e d p r e p a r a t i o n s t e p , t h e c h e m i s t r y of t h e d i s s o l v e d f u e l is adjusted f o r solvent extraction. The d e t a i l s of s o l v e n t e x t r a c t i o n s t r o n g l y depend on t h e c h a r a c t e r i s t i c s r e q u i r e d f o r t h e plutonium and uranium p r o d u c t s . Our e v a l u a t i o n w i l l be based on a c o n v e n t i o n a l Purex s o l v e n t e x t r a c t i o n , i n which t h e s o l v e n t e x t r a c t i o n s t e p y i e l d s p u r e uranium and plutonium p r o d u c t s . The p r o d u c t - c o n v e r s i o n s t e p c o n v e r t s aqueous n i t r a t e s o l u t i o n s of plutonium and uranium i n t o t h e r e s p e c t i v e o x i d e s . The r e f e r e n c e d e s i g n i n c l u d e s o x a l a t e p r e c i p i t a t i o n f o l l o w e d by t h e r m a l decomposition.

E.2.3

F a b r i c a t i o n of Metal F u e l s f o r IFR

F a b r i c a t i o n of t h e metal c o r e and b l a n k e t f u e l s w i l l i n v o l v e separate operations i n the i n i t i a l steps. However, t h e same equipment can be used d u r i n g and a f t e r t h e f u e l - r o d assembly s t a g e . All f a b r i c a t i o n s t e p s must be conducted r e m o t e l y w i t h i n t h i c k containment s h i e l d i n g because b o t h t h e r e c y c l e uranium from t h e h a l i d e s l a g g i n g and t h e r e p r o c e s s e d plutonium/uranium/zirconium w i l l r e t a i n a p p r e c i a b l e q u a n t i t i e s of f i s s i o n products. F i g u r e E.3 shows a block diagram f o r n e t a l f u e l f a b r i c a t i o n , which i s i n a c c o r d w i t h t h e f a b r i c a t i o n of EBR I1 f u e l . A s i n t h e r e p r o c e s s i n g , t h e c a p a c i t y f o r f u e l f a b r i c a t i o n must be c a p a b l e of q u a n t i t i e s f o r t h e b r e e d i n g d e s i g n b a s i s , so t h a t t h e IFR w i l l have b r e e d i n g as a f u t u r e o p t i o n . Batch s i z e s may be l i m i t e d by c r i t i c a l i t y c o n s i d e r a t i o n s . The c r i t i c a l i t y s a f e t y a n a l y s i s f o r t h e s e p r o c e s s s t e p s has not been comp l e t e d , and t h e r e f o r e t h e e f f e c t of c r i t i c a l i t y on b a t c h s i z e s cannot be firmly evaluated. IFR b r e e d e r systems w i t h a t o t a l o u t p u t of 1300 MW(e) w i l l require a t o t a l processing-refabrication c a p a c i t y of 2 5 . 5 t / a (30 kg/d and 7 2 kg/d f o r t h e c o r e and b l a n k e t f u e l s , r e s p e c t i v e l y , f o r

ORNL

DWG 85-493

LOW-LEVEL LIQUID WASTE

IRRADIATED FUEL

Na REMOVAL

TO HEPA

m I

SOLIDS. AQUEOUS LlOUlDS, AND GASES

---

ORGANIC LIQUIDS

L___T___J 27

HLW VITRIFICATION

HVITRIFIED I $8

HLW

F i g u r e E.2. The b l o c k diagram f l o w s h e e t f o r Purex r e p r o c e s s i n g of f a s t r e a c t o r o x i d e f u e l . Numbered b l o c k s i n d i c a t e p r o c e s s s t e p s t h a t r e q u i r e s p a c e i n t h e containment f a c i l i t y , and a number common t o more t h a n one block i n d i c a t e s t h a t t h e s e s t e p s s h a r e a s p a c e . For example, t h e s o l v e n t e x t r a c t i o n s t e p s , 8 9 , are accomplished i n a n e i g h t - p a c k of c e n t r i f u g a l c o n t a c t o r s .

E-9

ORNL OWG 8 5 - 5 2 3

+ 6

CAN LOADING

WELD AND LEAK TEST

STOR E

AND BOW TEST

INSPECT

f--k--l TENSILE

DEMOLD AND SHEAR

STRAIGHTEN SPADE

CASTING

:*; 5' WASTE

I I I

CORE4 FUEL

INJECTION CASTING

SPADE

DEMOLD AND SHEAR

INSPECT

Figure E . 3 .

The block diagram flowsheet for fabrication of fast

reactor metal fuel.

Numbered blocks indicate processes or steps that

require space in the containment facility, and multiple numbers per A single number on several blocks block indicate duplicate equipment. indicates that these steps are accomplished in a common space.

250 d / a ) . Thus, as a r e s u l t of c r i t i c a l i t y c o n s i d e r a t i o n s , t h e c o r e and t h e b l a n k e t p r o c e s s may each r e q u i r e more t h a n one i n j e c t i o n c a s t i n g unit. The cast f u e l w i l l be c o o l e d and t h e mold removed. The s p e n t mold becomes TRU waste b u t c o u l d , p e r h a p s , be c l e a n e d t o l o w - l e v e l status. The f u e l w i l l t h e n be i n s p e c t e d and a c h e m i c a l a n a l y s i s completed. The f u e l t h a t p a s s e s i n s p e c t i o n w i l l be l o a d e d , a l o n g w i t h some sodium, i n t o new c l a d d i n g . The c l a d d i n g w i l l be s u b s e q u e n t l y welded and leak-tested. Approved f u e l r o d s w i l l be bonded i n t o b u n d l e s , and t h i s The p o s i t i o n i n g s p a d e on t h e bottom of t h e bonding w i l l be i n s p e c t e d . f u e l r o d s w i l l be s t r a i g h t e n e d , and t h e r o d s w i l l be loaded i n t o a n assembly. F i n a l l y , e a c h assembly w i l l be equipped w i t h t h e hexagonal can i n s e r t and welded. T e n s i l e t e s t i n g w i l l be performed, and t h e approved a s s e m b l i e s w i l l be examined t o a s s u r e meeting t h e r e q u i r e m e n t s for insertion into the reactor.

E.2.4

F a b r i c a t i o n of Oxide F u e l s

Feed material f o r f a b r i c a t i o n of o x i d e f u e l s w i l l have r e l a t i v e l y low gamma a c t i v i t y because t h e Purex p r o c e s s removes e s s e n t i a l l y a l l of t h e fission-product e l e m e n t s from t h e plutonium/uranium p r o d u c t s . T h e r e f o r e , t h i s f a b r i c a t i o n can be housed i n a low-level c o n t a i n m e n t facility. However, automated remote o p e r a t i o n s and maintenance w i l l be r e q u i r e d because of t h e long-term i n c r e a s e i n t h e even-numbered p l u t o n ium i s o t o p e s . The 130041W(e) r e a c t o r system w i l l r e q u i r e 8, 9 , and 18 t / a of c o r e , a x i a l , and r a d i a l b l a n k e t f u e l s , r e s p e c t i v e l y . While t h e Purex r e p r o c e s s i n g must h a n d l e a l l 35 t / a of s p e n t f u e l , t h e f a b r i c a t i o n f a c i l i t y w i l l p r e p a r e o n l y t h e c o r e f u e l (8 t / a ) ; t h e b l a n k e t The vendor f u e l ( 2 7 t / a ) w i l l be purchased from a n i n d e p e n d e n t vendor. could be any of t h o s e t h a t c u r r e n t l y s u p p l y LWR f u e l . A block-type s c h e m a t i c f o r f a b r i c a t i o n of o x i d e b r e e d e r f u e l i s shown i n Fig. E . 4 . This flowsheet is i n accord with t h e f a b r i c a t i o n The r e c y c l e d flow-sheet f o r t h e Secure Automated F a b r i c a t i o n l i n e . The Pu02 and t h e U02 are f i r s t blended i n t h e p r o p e r b a t c h q u a n t i t i e s . mixed o x i d e i s m i l l e d t o a c h i e v e u n i f o r m i t y , and a b i n d e r material i s added. The f i n e material i s t h e n compacted i n t o g r a n u l e s , and a l u b r i T h i s m i x t u r e i s p r e s s e d i n t o p e l l e t s and loaded i n t o c a n t is added. b o a t s f o r h i g h - t e m p e r a t u r e t r e a t m e n t , which s e r v e s t o remove t h e b i n d i n g m a t e r i a l and s i n t e r t h e p e l l e t s . The s i n t e r e d p e l l e t s undergo s e v e r a l g r i n d i n g , g a u g i n g , c l e a n i n g , and i n s p e c t i o n s t e p s b e f o r e t h e y a r e l o a d e d i n t o the cladding jackets. The loaded j a c k e t s are f i l l e d w i t h helium and welded c l o s e d . HeLium l e a k - t e s t i n g and u l t r a s o n i c t e s t i n g are carr i e d out successively. The f u e l r o d s proceed t h r o u g h f i s s i l e a s s a y and p h y s i c a l i n s p e c t i o n , and r o d s t h a t p a s s a l l i n s p e c t i o n s are wrapped w i t h s p a c e r w i r e and assembled i n t o bundles. A f i n a l i n s p e c t i o n of t h e assembled bundles completes t h e f a b r i c a t i o n p r o c e s s .

E-ll

ORNL

2 1

RECYCLE

BATCHING BLENDING

MILLING AND BINDER ADDITION

r s

COMPACTION AND GRANULATION

LUBRICANT ADDITION

SURFACE INSPECTION

GRINDING

PELLET STORAGE

DEBINDING AND SINTERING

BOAT CLEANUP AND INSPECTION

COLUMN MAKEUP

HELIUM FILL AND WELD

PIN LOAD

STORE

INSPECT

DWG 85-524

WRAP

I C -

ANALYSIS

HELIUM LEAK TEST

VISUAL DIMENSION CHECK

PELLET PRESSING AND BOAT LOADING

WELD ULTRASONIC TESTING

FISSILE ASSAY COMPONEN1 PLACEMENT

E-12

E.3

COSTS OF DEMONSTRATION PLANTS FOR REPROCESSING AND REFABRICATING METAL AND OXIDE FUELS

C o s t s have been e s t i m a t e d f o r t h e f u e l c y c l e p l a n t s f o r f a s t react o r f a c i l i t i e s w i t h 1300-MW(e) o u t p u t s . I n Table E . l , through-puts f o r such r e p r o c e s s i n g f a c i l i t i e s are g i v e n as t o n n e s p e r y e a r ( t / a ) f o r metal f u e l from an IFR c o n c e p t u a l r e a c t o r o p e r a t i n g as a b r e e d e r and f o r Reprocessing of o x i d e f u e l from a PRISM c o n c e p t u a l b r e e d e r r e a c t o r . e i t h e r t y p e of f u e l i s conducted i n r e m o t e l y o p e r a t e d , s h i e l d e d f a c i l ities. R e f a b r i c a t i o n of both t h e c o r e and b l a n k e t of t h e metal f u e l i s conducted i n remotely o p e r a t e d , s h i e l d e d f a c i l i t i e s . However f o r o x i d e f u e l s , only t h e c o r e i s r e f a b r i c a t e d r e m o t e l y , t h e b l a n k e t f u e l i s purchased from a commercial vendor. Table E.l. F u e l t h r o u g h p u t s ( t / a ) f o r r e p r o c e s s i n g and r e f a b r i c a t i n g metal and o x i d e f u e l s from 1300-MW(e) f a s t r e a c t o r s

Core A x i a l Metal f u e l Oxide f u e l

7.5 8

0 9

Ref a b r i R a d i a l Reprocess c a t i o n Purchase 18 18

25 e5 35

25.5 8

0 27

Total for remote operations 51

The c o s t s of r e p r o c e s s i n g and r e f a b r i c a t i o n f a c i l i t i e s are h i g h l y dependent on t h e s i z e s of t h e containment b u i l d i n g s , because of t h e s h i e l d i n g and v e n t i l a t i o n r e q u i r e m e n t s . Therefore, t h e r e l a t i v e costs of f u e l c y c l e s f o r oxide o r m e t a l FBR f u e l s can be based on t h e r e l a t i v e s i z e s of t h e r e q u i r e d f a c i l i t i e s . As a f i r s t a p p r o x i m a t i o n f o r compari n g c o s t s , we have assumed t h a t c a p i t a l c o s t s are p r o p o r t i o n a l t o t h e number of p r o c e s s s t e p s t h a t r e q u i r e space i n t h e s h i e l d e d , remotely operated f a c i l i t y . W e have numbered such s t e p s i n Figs. E.l-E.4. S e v e r a l s t u d i e s have c a l c u l a t e d and examined t h e e f f e c t s of v a r i o u s parameters on r e p r o c e s s i n g c o s t s f o r o x i d e f u e l s . Those are summarized i n Ref. 5. Those c o s t s and t h e c o s t s h e r e i n are e x p r e s s e d as c u r r e n t d o l l a r l e v e l i z e d c o s t s (1984 d o l l a r s ) . I f t h e annual l e v e l i z e d f i x e d charge r a t e had been based upon c o n s t a n t d o l l a r s , t h e a p p a r e n t c o s t would have been lower. Using t h e same s c a l i n g f a c t o r s (0.5) t h a t are used i n t h o s e s t u d i e s and assuming, as d i d Delene e t a1.,5 t h a t a f a c i l i t y f o r r e p r o c e s s i n g 150 t / a would c o s t $1.02 b i l l i o n , we estimate t h a t t h e c a p i t a l c o s t of an o x i d e f u e l r e p r o c e s s i n g f a c i l i t y f o r a 1300-MW(e) LMR would be $492 m i l l i o n . The v a l i d i t y of t h i s c o s t f i g u r e i s supp o r t e d by t h e r e c e n t l y p u b l i s h e d c o s t s f o r t h e newest LWR r e p r o c e s s i n g p l a n t i n t h e F e d e r a l Republic of Germany.6 I n t h a t document, $1.6 b i l l i o n i s t h e c o s t r e p o r t e d f o r a 500-t/a LWR r e p r o c e s s i n g p l a n t (excludi n g c o s t s of t h e r e f a b r i c a t i o n f a c i l i t y ) . When s c a l e d downward t o t h e 35-t/a p l a n t , t h i s y i e l d s $423 m i l l i o n . S i n c e t h e c o s t s of r e p r o c e s s i n g LMR f u e l s are g e n e r a l l y h i g h e r (up t o 50%) t h a n t h o s e f o r LWR f u e l s , t h e

E-13 two d e r i v e d c o s t s are comparable, and c o n f i d e n c e i n t h e i r v a l i d i t y i s increased. However, p r e l i m i n a r y r e s u l t s of an ORNJL s t u d y c u r r e n t l y i n p r o g r e s s f o r a small o n s i t e f a c i l i t y s u g g e s t a c o s t of $270 m i l l i o n compared t o t h e above d e r i v e d $492 m i l l i o n f o r r e p r o c e s s i n g of o x i d e f u e l s i n a 35 t / a f a ~ i l i t y . W ~e have used t h e s e t w o c o s t f i g u r e s t o c a l c u l a t e lower and upper boundary c o s t s f o r r e p r o c e s s i n g and r e f a b r i c a t i o n . The o x i d e f u e l r e p r o c e s s i n g c o s t s were d e r i v e d from t h e s e v a l u e s , w h i l e t h e c o s t s f o r r e f a b r i c a t i n g t h e o x i d e f u e l and b l a n k e t were based on t h e h i g h end of t h e v a l u e s g i v e n i n Table 2.12 of Ref. 5. The high-end v a l u e s were used t o r e f l e c t t h e c o s t d i s a d v a n t a g e f o r a small-throughput plant. The c o r r e s p o n d i n g c o s t estimates f o r a metal f u e l r e p r o c e s s i n g and r e f a b r i c a t i n g p l a n t have not been p r e p a r e d i n t h e same d e t a i l as t h o s e f o r t h e oxide f u e l plants. Because of t h i s , t h e v a l u e s d e r i v e d f o r t h e metal f u e l c y c l e do n o t have t h e same v a l i d i t y as t h o s e f o r t h e o x i d e f u e l cycle. However, we t h i n k t h e r e s u l t s are g e n e r a l l y c o r r e c t and A more d e t a i l e d d e s i g n s t u d y a c c e p t a b l e as a b a s i s f o r comparison. would be r e q u i r e d t o p r o v i d e c o s t estimates of e q u a l v a l i d i t y t o t h o s e f o r t h e oxide f u e l plants.* S i n c e t h e number of major s t e p s r e q u i r e d f o r p r o c e s s i n g of metal f u e l s i s comparable t o t h a t r e q u i r e d f o r o x i d e f u e l s ( s e e F i g s . E . l and E.2), t h e c o s t of t h e o x i d e r e p r o c e s s i n g p l a n t w a s used as a c o s t b a s i s However, metal f u e l r e p r o c e s s i n g f o r t h e metal r e p r o c e s s i n g p l a n t . equipment may n o t r e q u i r e t h e head h e i g h t t h a t i s needed f o r o x i d e r e p r o c e s s i n g equipment. T h e r e f o r e , t h e i n i t i a l b a s e c o s t f o r t h e metal f u e l w a s reduced by 20% b e f o r e s c a l i n g f o r c a p a c i t i e s w a s done. The 20% r e d u c t i o n i s based on t h e r e s u l t i n g reduced need f o r c o n c r e t e and r e i n forcement, r e l a t i v e t o t h e t o t a l r e i n f o r c e d concrete requirements f o r t h e t o t a l c e l l . T h i s reduced base c o s t was t h e n a d j u s t e d f o r s i z e based on c a p a c i t y , u s i n g a 0.5 s c a l i n g f a c t o r . The f a c i l i t y r e q u i r e m e n t s f o r r e p r o c e s s i n g o r r e f a b r i c a t i n g m e t a l f u e l s are similar. T h e r e f o r e , t h e c o s t s f o r r e f a b r i c a t i o n of t h e metal f u e l s were based on t h e r e l a t i v e number of s t e p s r e q u i r e d f o r r e f a b r i c a t i o n (i.e., 20) as compared w i t h t h e number of s t e p s r e q u i r e d f o r Thus, t h e r e p r o c e s s i n g of t h e metal f u e l (i.e., 2 5 ) t o t h e 0.5 power. r e f a b r i c a t i o n c a p i t a l c o s t s are: (2O/25)Oo5 = 0.894 t i m e s t h e metal reprocessing c a p i t a l costs. The t o t a l waste c o s t s were based on t h e r a t e of 1 mill/kWh and hence were $9.1 m i l l i o n a n n u a l l y . The c o s t of new b l a n k e t o x i d e f u e l w a s based on t h e h i g h range i n Table 2.12 of Ref. 5. The h i g h r a n g e , $500/kg, w a s used because of t h e r e l a t i v e l y low q u a n t i t y t o be purchased. Hardware c o s t s , e s t i m a t e d a t $50,000 p e r f u e l assembly, w e r e

*Costs were n o t a v a i l a b l e from ANL on t h e IFR f u e l c y c l e f a c i l i t i e s d u r i n g t h e p e r i o d i n which t h i s r e p o r t was being p r e p a r e d . However, s i n c e t h a t t i m e ANL has developed a concept and c o s t estimates. ANL should be c o n t a c t e d f o r needed d e t a i l s of t h i s i n f o r m a t i o n .

E-14 based on e x p e r i e n c e a t t h e FFTF and t h e EBR 11.. were s c a l e d u s i n g a s i z i n g exponent of 0.7.

The o p e r a t i n g c o s t s

The c o s t summary i s g i v e n i n Table E.2. This information suggests t h a t t h e r e i s no s i g n i f i c a n t economic advantage i n a m e t a l - f u e l o r a n o x i d e - f u e l FBR based on t h e c o s t s of r e p r o c e s s i n g and r e f a b r i c a t i n g t h e fuel. C a l c u l a t i o n s were made t o p r o v i d e comparable v a l u e s f o r p r o c e s s i n g oxide f u e l i n a l a r g e f u e l c y c l e f a c i l i t y (1500 t / a ) , assuming t h a t i t e x i s t e d and t h a t t h e f u e l was both r e p r o c e s s e d and f a b r i c a t e d t h e r e . The c o s t b a s i s w a s t a k e n from Table 2 . 1 3 of Ref. 5. The r e s u l t s showed c o s t s of 4.7 t o 6.3 mills/kWh f o r 80% r e a c t o r c a p a c i t y f a c t o r s . It i s obvious t h a t t h e c o s t s d e r i v e d h e r e f o r a 35-t/a f a c i l i t y are h i g h when c o n v e r t e d t o t h e u n i t c o s t ( $ / k g ) b a s i s o r t o mills/kWh, and when compared t o c o s t s i n a l a r g e f a c i l i t y . T h i s i s a f u n c t i o n of t h e low c a p a c i t y r e q u i r e m e n t s f o r e i t h e r of t h e p r o c e s s e s . The 25-35 t / a p l a n t s a r e a f a c t o r of 50 smaller, and t h e c o s t v a l u e s r e f l e c t t h i s ; however, t h e c o s t comparisons should be more v a l i d t h a n t h e a b s o l u t e v a l u e s , s i n c e b o t h t h e metal and t h e o x i d e p r o c e s s e s were c o s t e d on a p p r o x i m a t e l y t h e same b a s i s . Options o t h e r t h a n i n t e g r a l r e p r o c e s s i n g have been s u g g e s t e d , as f o l l o w s :

S t o r e t h e s p e n t f u e l u n t i l s u f f i c i e n t q u a n t i t i e s are accumulated f o r l a r g e - s c a l e commercial r e p r o c e s s i n g .

Ship t h e s p e n t f u e l t o a l a r g e i n t e r n a t i o n a l r e p r o c e s s i n g f a c i l i t y s e t up as a c o o p e r a t i v e v e n t u r e .

Reprocess f u e l i n a s m a l l d e d i c a t e d e x p e r i m e n t a l f a c i l i t y such as BRET, s u b s i d i z e d by r e s e a r c h and development funds ( f o r e a r l y power plants).

Reprocess LMFBR f u e l "hybrid" c o n c e p t ) .

Reprocess IMFBR f u e l i n e x i s t i n g u t i l i z i n g p a r t of t h e i r c a p a c i t y a p p r o p r i a t e m o d i f i c a t i o n s are made.

E.4

joint

facility

U.S. for

with

LWR

fuel

(the

reprocessing f a c i l i t i e s , c i v i l i a n purposes, a f t e r

I S S U E S THAT NEED ATTENTION

The c o l o c a t i o n of f u e l r e p r o c e s s i n g f a c i l i t i e s w i t h f a s t r e a c t o r s can r e q u i r e t h a t a l l r e g u l a t o r y concerns f o r both t h e r e a c t o r and i t s a s s o c i a t e d r e p r o c e s s i n g f a c i l i t y be a d d r e s s e d b e f o r e a p p r o v a l of t h e r e a c t o r is obtained. W e have d e f i n e d s e v e r a l i s s u e s i n e a c h of s i x areas of t h e r e a c t o r - r e p r o c e s s i n g - r e f a b r i c a t i o n combination and have added a comment on each i s s u e .

E-15

T a b l e E.2. Cost summary f o r r e p r o c e s s i n g and r e f a b r i c a t i n g metal and oxide FBR f u e l a

Fuel t y p e

Reprocessing c o s t s ( $ l o 6 ) Annual capital

Capi t a 1

Annual operating

T o t a l annual

Metal f u e l (20-year) 25.5 t / a (30-year)

184-3 3 6 184-33 6

42-76 3 1-56

13 13

55-89 44-49

Oxide f u e l (20-year) 3 5 t / a (30-year)

270492 270492

61-1

45-

16 16

71-127 61- 98

11 82

R e f a b r i c a t i o n annual c o s t s ( $ l o 6 )

Metal f u e l (20-year) 25.5 t / a (30-year) Oxide f u e l (20- o r 8 t/a 30-year)

C a p i t a l and operating

Hardware

Pur c h a s e s

Total

48-80 39-61

10 10

58-90 49-7 1

13.5

25.6

Combined annual c o s t s ( $ l o 6 ) Repro.

Ref ab.

Waste

Total

Metal f u e l (20-year) (30-year)

55-89 44-69

58-90 49-7 1

9.1 9.1

122-1 88 102-149

Oxide f u e l (20-year) (30-year)

77-127 61- 98

9.1 9.1

126176 110-147

39 39

Busbar c o s t s a t 80% r e a c t o r c a p a c i t y ( m i 11s/ kWh)

Metal f u e l (20-year) (25.5 t / a ) (30-year)

13.4-20.6 11.6-16.3

Oxide f u e l (20-year) (35 t / a ) (30-year)

13.8-19.3 12.1-16.1

Oxide f u e l (20-Year) 1500 t / a (30-year)

6.3 4.7

aA c o n s t a n t waste c o s t of 1 mill/kWh, o r $9.1 m i l l i o n p e r y e a r , i s assumed.

E-16 1.

Waste One of t h e major q u e s t i o n s t h a t needs t o be r e s o l v e d f o r t h e metal f u e l p r o c e s s i n g concept i s the means of h a n d l i n g t h e waste. Before t h i s q u e s t i o n can be answered, c o n s i d e r a b l e e x p e r i mental work i s r e q u i r e d t o d e f i n e where each of t h e major waste Once t h e i s o t o p e s w i l l r e s i d e as a r e s u l t of t h e s e p r o c e s s e s . l o c a t i o n s and t h e q u a n t i t i e s of t h e wastes are d e f i n e d , s p e c i f i c d i s p o s a l methods can be determined.

I n t h e area of waste d i s p o s a l , t h e r e are many q u e s t i o n s r e l a t i v e t o t h e s p e c i f i c c r i t e r i a f o r t h e wastes and waste c o n t a i n e r s f o r Such e i t h e r metal o r oxide f u e l s . i f i c a t i o n b e f o r e f i n a l d e s i g n could f u e l , c o n s i d e r a b l e development work proposed p r o c e s s e s , p a r t i c u l a r l y i n t h e d i s p o s a l product. 2.

q u e s t i o n s would r e q u i r e c l a r be completed. For t h e metal would be n e c e s s a r y t o v e r i f y t h e area of imperviousness of

Environment - The e n v i r o n m e n t a l r e q u i r e m e n t s f o r t h e t o t a l f u e l c y c l e need t o be c l a r i f i e d b e f o r e t h e e x p e r i m e n t a l work i s comp l e t e d , p a r t i c u l a r l y f o r metal f u e l , s i n c e l i t t l e e x p e r i e n c e and no s o u r c e terms a r e a v a i l a b l e . This would r e q u i r e an e a r l y d e d i c a t i o n t o , and f u n d i n g for, such a p r o j e c t . Again, c l a r i f i c a t i o n i s needed as t o what s p e c i f i c c r i t e r i a o r r e g u l a t i o n s would apply t o t h e releases from an FBR f u e l c y c l e . The c u r r e n t r e g u l a t i o n s (40CFR190) a p p l y s p e c i f i c a l l y t o t h e "uranium f u e l c y c l e " f o r l i g h t - w a t e r r e a c t o r s . It i s n o t c l e a r whether 40CFR61 w a s i n t e n d e d t o cover f u e l r e p r o c e s s i n g from nonuranium f u e l c y c l e s (Par. I V B). This needs c l a r i f i c a t i o n .

S a f e t y and L i c e n s i n g - A t p r e s e n t , t h e r e are no approved d e s i g n Can t h e s e be c r i t e r i a f o r LMRs o r f o r t h e f u e l c y c l e f a c i l i t i e s . approved i n t i m e t o be i n c l u d e d i n t h e d e s i g n p r o c e s s ? A t p r e s e n t t h e r e are a l s o no r e g u l a t i o n s (NRC) which d e f i n e t h e criteria f o r f u e l cycle f a c i l i t i e s . Appendix P t o lOCFR!jO, which has been proposed ( b u t not approved) , c o n t a i n s s a f e t y c r i t e r i a based on aqueous p r o c e s s i n g . It could be m o d i f i e d t o cover pyrop r o c e s s i n g ; however, t h i s would have t o be done w e l l i n advance of t h e f i n a l d e s i g n of a d e m o n s t r a t i o n f a c i l i t y , i n o r d e r f o r t h e req u i r e m e n t s t o be i n c l u d e d i n t h e f i n a l d e s i g n .

It i s n o t clear t h a t t h e s a f e g u a r d s r e q u i r e m e n t s f o r t h e metal f u e l r e p r o c e s s i n g and f a b r i c a t i o n would be t h e same as t h o s e f o r s i m i l a r o p e r a t i o n s on t h e o x i d e f u e l . However, t h e metal f u e l would always be h i g h l y r a d i o a c t i v e and t h u s less a t t r a c t i v e f o r d i v e r s i o n . For e i t h e r t h e o x i d e o r m e t a l f u e l c y c l e , t r a n s p o r t a t i o n i s reduced by using the i n t e g r a l f u e l cycle. Would any s a f e t y o r l i c e n s i n g w a i v e r s be r e q u i r e d f o r e i t h e r FMEF o r FCF i n o r d e r f o r them t o meet DOE r e q u i r e m e n t s , and could t h e s e w a i v e r s be o b t a i n e d ?

E-17

P u b l i c Acceptance - P u b l i c a c c e p t a n c e has been a major problem f o r less complex p r o j e c t s t h a n t h e s e t h a t are proposed. Could t h i s become a major problem? Although t h e p u b l i c may a c c e p t a r e a c t o r o r s e v e r a l r e a c t o r s a t a s i t e , t h e a d d i t i o n of a f u e l c y c l e f a c i l i t y t o t h i s " n u c l e a r park," may r e q u i r e a g r e a t d e a l more e d u c a t i o n t h a n b e f o r e . This could be p a r t i c u l a r l y i m p o r t a n t f o r t h e management and d i s p o s a l of wastes

I n d u s t r y Acceptance - A major c o n s i d e r a t i o n w i l l be t h e w i l l i n g n e s s of i n d u s t r y t o become i n v o l v e d i n a complex, total-power program such as t h a t proposed f o r t h e IFR. How would i n d u s t r y propose t o handle t h i s ? A.

I n t h e c o u r s e of t h i s s t u d y , we have observed t h a t u t i l i t i e s would n o t f e e l c o m f o r t a b l e w i t h s t a f f i n g and managing t h e d i v e r s e f a c i l i t i e s required f o r a t o t a l f u e l cycle. T h e i r background and t r a i n i n g are r e l a t e d t o power g e n e r a t i o n and do n o t i n c l u d e t h e c o m p l e x i t i e s , c o s t s , and r i s k s of t h e s e o t h e r It may be more p r a c t i c a l t o have a s e p a r a t e o p e r a t i n g elements. organization with the appropriate t e c h n i c a l expertise.

B. A r e t h e economics of one c e n t r a l f u e l c y c l e compatible w i t h a l i m i t e d - (one-) r e a c t o r complex d u r i n g e a r l y y e a r s when o n l y one o r two r e a c t o r s are i n o p e r a t i o n ?

A f u e l c y c l e f a c i l i t y must be o r i g i n a l l y d e s i g n e d and b u i l t t o h a n d l e t h e t o t a l o u t p u t from a l l t h e r e a c t o r s a t t h e s i t e . T h e r e f o r e , t h e major c o s t s - t h o s e of c o n s t r u c t i o n would be i n c u r r e d a t some t i m e b e f o r e t h e t o t a l c a p a c i t y of t h e f a c i l i t y was needed. The i n t r o d u c t i o n of t h e f u e l c y c l e might be d e l a y e d somewhat by s t o r i n g t h e f u e l a f t e r d i s c h a r g e . This would proAn economic b a l a n c e v i d e an i n v e n t o r y f o r t h e f u t u r e r e a c t o r s . would have t o be made i n o r d e r t o d e f i n e t h e optimum s t o r a g e period. The normal p l a n t l i f e f o r r e p r o c e s s i n g i s assumed t o be 20 t o 30 y e a r s , as opposed t o an assumed r e a c t o r l i f e of 30 t o 40 y e a r s , however, t h e optimum l i f e t i m e s f o r b o t h r e a c t o r s and r e p r o c e s s i n g p l a n t s r e q u i r e f u r t h e r s t u d y and may prove t o be much l o n g e r .

C. How l a r g e an a n a l y t i c a l complex w i l l be r e q u i r e d ? R e a c t o r s , per se, do not r e q u i r e an e x t e n s i v e a n a l y t i c a l capability. The o v e r a l l complex would r e q u i r e e x t e n s i v e remotely operated f a c i l i t i e s f o r determining chemical, m e t a l l u r g i c a l , p h y s i c a l p r o p e r t i e s , and f o r a n a l y t i c a l c h e m i s t r y measurements.

D. Does t h e o p e r a t o r have s u f f i c i e n t backup t e c h n i c a l c a p a b i l i t i e s a v a i l a b l e ( a n a l y t i c a l l a b o r a t o r i e s , m e t a l l u r g i c a l caves, e t c . ) t o h e l p r e s o l v e day-to-day problems?

E-18 The s u p p o r t f a c i l i t i e s r e q u i r e d t o s e r v i c e a r e a c t o r f u e l c y c l e complex would be much more e x t e n s i v e t h a n t h o s e r e q u i r e d f o r a r e a c t o r alone.

E. Can r e a c t o r ( s ) be dependent on o n l y one f u e l s o u r c e and one d i s p o s a l method? How do r e a c t o r s o p e r a t e i n case of a 1- t o 2-year shutdown of f u e l c y c l e ? A l l of t h e f a c i l i t i e s i n v o l v e d i n t h e r e a c t o r c y c l e - f u e l s o u r c e , f u e l s t o r a g e and d i s p o s a l , and waste d i s p o s a l - are remotely o p e r a t e d and m a i n t a i n e d . They would be d i f f i c u l t t o d u p l i c a t e on s h o r t s c h e d u l e i n case a major problem developed i n any p a r t of t h e system. Thus, the metal f u e l r e a c t o r s would n o t have a f a l l - b a c k o p t i o n , u n l e s s and u n t i l s e v e r a l s i m i l a r f a c i l i t i e s were a v a i l a b l e . The l a t t e r c i r c u m s t a n c e would r e q u i r e shipment of s p e n t and r e f a b r i c a t e d f u e l .

F. What is t h e d e s i g n l i f e of t h e f u e l c y c l e complex? r e f u r b i s h e d - and how of t e n ?

Can i t b e

The d e s i g n l i f e of f u e l c y c l e f a c i l i t i e s i s normally 2030 y e a r s . The Savannah River P l a n t i s 30 y e a r s o l d and s t i l l operating well. There are no o t h e r p l a n t s t h a t have o p e r a t e d longer. It would appear f e a s i b l e t o r e p l a c e equipment and serv i c e s w i t h i n a p l a n t t o e x t e n d l o n g e v i t y , p r o v i d i n g remote h a n d l i n g c a p a b i l i t i e s were a d e q u a t e . G.

How much plutonium i s needed f o r t h e r e a c t o r program, a t what rate would i t be s u p p l i e d , and from what s o u r c e ? Two q u e s t i o n s are concerned w i t h t h e a v a i l a b i l i t y of f u e l (and plutonium) f o r i n i t i a l s t a r t u p . F i r s t , i s plutonium a v a i l a b l e t o p r o v i d e enough metal f u e l (e.g., one f u e l assembly p e r week) t o s u p p o r t t h e p i l o t - p l a n t program f o r t h e 2 t o 3 y e a r s t h a t i s n e c e s s a r y t o develop t h e p r o c e s s and waste-process system? And second, what i s t h e s o u r c e of t h e plutonium and t h e manufacturi n g c a p a b i l i t y t o produce t h e i n i t i a l two t o t h r e e c o r e s t h a t would be r e q u i r e d f o r e i t h e r t h e metal- o r o x i d e - f u e l demonstrat i o n r e a c t o r p r i o r t o r e c y c l i n g f u e l from t h e f u e l c y c l e f a c i l i ties? W i l l t h e r e be any problem i n f i n d i n g a vendor who w i l l gear up f o r such a l i m i t e d program?

Reactor I n t e r f a c e s

A. Can a r e a c t o r o p e r a t e t h a t may be n e c e s s a r y tonium due t o r e c y c l e , compensate f o r t h i s ? the fuel?)

w i t h t h e h i g h e r plutonium c o n c e n t r a t i o n s t o compensate f o r t h e l e s s - f i s s i l e pluo r does t h e a d d i t i o n of t h e b l a n k e t f u e l (Would t h i s a f f e c t t h e m e l t i n g p o i n t of

E-19 With e a c h r e c y c l e of f u e l , t h e n o n f i s s i l e i s o t o p e s of plutonium i n c r e a s e ; t h u s , h i g h e r - q u a l i t y plutonium may be r e q u i r e d t o proA h i g h e r plutonium concenv i d e t h e r e q u i s i t e f i s s i l e loading. t r a t i o n , w i t h o u t o t h e r a d j u s t m e n t s , could r e s u l t i n a lower melting point f o r the fuel. T h i s would have t o be e v a l u a t e d from t h e r e a c t o r s a f e t y v i e w p o i n t . These changes may be magnif i e d d u r i n g t h e i n i t i a l p h a s e s , when t h e f i s s i l e material i s changing from 235U t o plutonium. B.

How l a r g e a v a r i a n c e i n s p e c i f i c a t i o n s of f u e l w i l l t h e system accept? V a r i a t i o n s i n metal f u e l a l l o y c o m p o s i t i o n and f i s s i l e composit i o n can a f f e c t r e a c t o r performance. They can a l s o a f f e c t t h e p r e c i s i o n of t h e burnup c a l c u l a t i o n s , which may be t h e i n p u t Previous reactor cores v a l u e s f o r t h e f u e l c y c l e SNM b a l a n c e . ( a l b e i t e x p e r i m e n t a l i n n a t u r e ) have had h i g h a c c u r a c y and prec i s i o n r e q u i r e m e n t s f o r f u e l composition. In t h i s case, b o t h t h e a n a l y t i c a l d e t e r m i n a t i o n s and t h e f i n a l a d j u s t m e n t w i l l be accomplished by remote means, which may n o t produce t h e d e s i g n e d uniformity.

C. Is t h e f u e l t o be s p e c i f i e d by p e r c e n t a g e of plutonium, percent a g e of f i s s i l e plutonium o r t o t a l r e a c t i v i t y ? be determined?

How i s t h i s t o

If r e a c t i v i t y measurements are r e q u i r e d , t h e n s p e c i a l instrument a t i o n w i l l have t o be developed. D.

How are uranium/plutonium c o n c e n t r a t i o n s c o n t r o l l e d t o meet req u i r e m e n t s of ( B ) and ( C ) above?

A s e p a r a t e s t e p may be needed between r e p r o c e s s i n g and r e f a b r i c a t i o n which would permit composition a d j u s t m e n t . E.5

Conclusions

The f l o w s h e e t s d e s c r i b e d h e r e a p p e a r t o p r o v i d e a v i a b l e p r o c e s s f o r e i t h e r t h e oxide- o r t h e m e t a l - f u e l c y c l e . It i s r e c o g n i z e d t h a t a d d i t i o n a l development work i s n e c e s s a r y f o r t h e metal f u e l c y c l e , b u t t h i s does n o t a p p e a r t o p r e s e n t a major problem. Although some areas w i t h i n t h e metal f u e l r e p r o c e s s i n g - w a s t e h a n d l i n g f l o w s h e e t s may change as more development work i s done, t h e r e i s no r e a s o n t o e x p e c t t h e s e m o d i f i c a t i o n s t o a f f e c t our o v e r a l l c o n c l u s i o n s . It must be emphasized t h a t t h e c o s t v a l u e s p r e s e n t e d h e r e are gene r i c i n n a t u r e and may be more a c c u r a t e i n a c o m p a r a t i v e s e n s e t h a n i n an a b s o l u t e sense. It must a l s o be p o i n t e d o u t t h a t t h e p r i n c i p a l c o s t a d v a n t a g e of t h e m e t a l - f u e l c y c l e ( i . e . , t h e r e l a t i v e l y small number of

E-20 s t e p s r e q u i r e d f o r r e f a b r i c a t i o n ) , i s l a r g e l y o f f s e t by b l a n k e t f a b r i c a tion costs. The b l a n k e t f o r t h e metal f u e l must be r e f a b r i c a t e d r e m o t e l y , w h i l e t h e o x i d e b l a n k e t can be f a b r i c a t e d by an e x i s t i n g LWR f u e l f a b r i c a t i o n u s i n g c o n t a c t means, which i s c o n s i d e r a b l y less expensive. Because of t h e s e c o n s i d e r a t i o n s , no a p p r e c i a b l e d i f f e r e n c e was found between t h e o v e r a l l c o s t s f o r t h e m e t a l - f u e l c y c l e and t h o s e f o r t h e o x i d e - f u e l c y c l e . Although t h e c a l c u l a t e d u n i t o r bus b a r c o s t s f o r a s m a l l (35 t / a ) i n t e g r a t e d f u e l c y c l e do n o t a p p e a r t o be a t t r a c t i v e , t h e c o r r e s p o n d i n g f u e l c y c l e c o s t s f o r a p r o j e c t e d l a r g e (1500 t / a ) f a c i l i t y a p p e a r t o be c o m p e t i t i v e . A much more d e t a i l e d c o s t s t u d y would be r e q u i r e d t o r e f i n e t h e v a l u e s p r e s e n t e d here. Consideration must a l s o be g i v e n t o t h e i d e n t i f i e d p o t e n t i a l r e g u l a t o r y , s o c i a l , and i n d u s t r i a l acceptance issues. As discussed, t h e schedules presented here i n d i c a t e t h a t e i t h e r t h e m e t a l - f u e l o r t h e o x i d e - f u e l c y c l e could be c l o s e d w i t h i n t h e a l l o t t e d t i m e frame (2000-2010). Although t h e s c h e d u l e s c o n t a i n leeway t o prov i d e f o r small d e l a y s i n o b t a i n i n g f u n d i n g o r i n c l a r i f y i n g development u n c e r t a i n t i e s , t h e r e are s e v e r a l t e c h n i c a l and i n s t i t u t i o n a l problems which must be r e s o l v e d e a r l y f o r any i n t e g r a l r e a c t o r and f u e l c y c l e f a c i l i t y t o meet t h e p r o j e c t e d t i m e frame.

E-21 REFERENCES FOR APPENDIX E

T h i s f l o w s h e e t was developed from t h a t i n i t i a l l y provided i n ANLIFR-7, Stream Flows and Compositions f o r P r e l i m i n a r y P y r o p r o c e s s F l o w s h e e t s , March, 1985. The f l o w s h e e t i n c l u d e s m o d i f i c a t i o n s found i n t h e ANL-IFR s e r i e s of r e p o r t s and provided by ANL s t a f f i n p e r s o n a l communications.

P r e l i m i n a r y S a f e t y A n a l y s i s R e p o r t , Vol. 4, Nuclear F u e l Recovery and R e c y c l i n g C e n t e r , XN-FR-32, NRC Docket No. 50-564, Exxon Nuclear Co., Inc. (1977).

M. J. L i n e b e r r y , R.

D. Phipps and J. P. Burelbach, Commercial-side IFR Fuel Cycle F a c i l i t y : Conceptual Design and Cost E s t i m a t e , ANL-IFR-25, October 1985.

D. H. Nyman, â&#x20AC;&#x153; S e c u r e Automated F u e l F a b r i c a t i o n , P r o c e e d i n g s , Conference on Remote Systems Technology, 2 , (1983).

I. Bowers, and M. L. Myers, A Reference Data Base f o r Nuclear and Coal-Fired Power G e n e r a t i o n Cost A n a l y s i s , DOE/NE 0044R (1985).

Nada S t a n i e , Nucl. F u e l 13-14 ( J u l y 1, 1985).

R. B a l e n t and J. M. Y e d i d i a , D r a f t , Large-Scale, Fuel Cycle P l a n , DOE/EPRI, J u l y 1985.

31st

J. G. Delene, H.

Burch, p r i v a t e communication, J u l y 1985. P r o t o t y p e Breeder

APPENDIX F 860 MM(e) LARGE HIGH TEMPERATURE GAS-COOLED REACTOR (HTGR)

The 2240 MW(t) r e a c t o r c o r e i s c o n t a i n e d w i t h i n a p r e s t r e s s e d conc r e t e r e a c t o r v e s s e l (PCRV), w i t h t h e c o r e i n t h e c e n t e r c a v i t y and t h e steam g e n e r a t o r s and a u x i l i a r y h e a t exchangers i n pods i n t h e PCRV s u r rounding t h e c0re.l The c o r e i s c o o l e d w i t h p r e s s u r i z e d h e l i u m , modera t e d and r e f l e c t e d w i t h g r a p h i t e , and f u e l e d w i t h a m i x t u r e of uranium It i s c o n s t r u c t e d of p r i s m a t i c hexagonal g r a p h i t e b l o c k s and thorium. w i t h v e r t i c a l h o l e s f o r c o o l a n t c h a n n e l s , f u e l r o d s , and c o n t r o l r o d s . Helium c o o l a n t f l o w s from f o u r e l e c t r i c - m o t o r - d r i v e n c i r c u l a t o r s downward t h r o u g h t h e c o r e , through f o u r steam g e n e r a t o r s , and back t o t h e circulators. S u p e r h e a t e d steam produced i n once-through steam generat o r s i s expanded t h r o u g h a tandem compound t u r b i n e g e n e r a t o r .

In a d d i t i o n t o t h e f o u r primary c o o l a n t l o o p s , t h r e e c o r e a u x i l i a r y h e a t removal system l o o p s are a l s o p r o v i d e d . Each l o o p c o n s i s t s of a g a s l w a t e r h e a t exchanger w i t h a n e l e c t r i c - m o t o r - d r i v e n circulator Should t h e main l o o p s not b e l o c a t e d i n a c a v i t y i n t h e PCRV w a l l . a v a i l a b l e , c o o l a n t i s c i r c u l a t e d from t h e r e a c t o r c o r e through t h e auxi l i a r y h e a t exchangers where h e a t i s t r a n s f e r r e d t o t h e c o r e a u x i l i a r y c o o l i n g water system f o r e v e n t u a l r e j e c t i o n from c o o l i n g t o w e r s t o t h e atmosphere. The a v e r a g e c o r e power d e n s i t y i s about 6 kW/1 and t h e o p e r a t i n g p r e s s u r e i s about 7 MPa. The c o o l a n t g a s e x i t s t h e c o r e a t a b o u t Steam c o n d i t i o n s a t t h e t u r b i n e i n l e t are 17.3 MPa and 541째C 690째C. p r o v i d i n g a t h e r m a l e f f i c i e n c y of 38%. The PCRV and a n c i l l a r y s y s t e m s containment b u i l d i n g , which i s a a r e housed inside a reactor c o n v e n t i o n a l s t e e l - l i n e d r e i n f o r c e d containment s t r u c t u r e . Typically, balance-of-plant systems are housed i n s e p a r a t e b u i l d i n g s depending on f u n c t i o n and s e r v i c e . The advantageous s a f e t y c h a r a c t e r i s t i c s of t h e l a r g e HTGR are based on t h e high h e a t c a p a c i t y of t h e g r a p h i t e c o r e and r e f l e c t o r , t h e h i g h t e m p e r a t u r e c a p a b i l i t y of t h e f u e l and m o d e r a t o r , t h e u s e of a c o o l a n t which does not change phase and h a s no r e a c t i v i t y e f f e c t a s s o c i a t e d w i t h d e n s i t y changes, t h e i n h e r e n t shutdown mechanisms a s s o c i a t e d w i t h a nega t i v e t e m p e r a t u r e c o e f f i c i e n t , and t h e u s e of a PCRV which i s a redundant s t r u c t u r e t h a t precludes c a t a s t r o p h i c f a i l u r e . The low c o r e power d e n s i t y i n combination w i t h t h e g r a p h i t e moderator l e a d s t o r e l a t i v e l y slow f u e l t e m p e r a t u r e rises f o l l o w i n g l o s s - o f - c o o l i n g a c c i d e n t s ; t h e g r a p h i t e moderator and t h e ceramic f u e l are s t a b l e t o v e r y h i g h temp e r a t u r e s , p r o v i d i n g a h i g h d e g r e e of f i s s i o n p r o d u c t r e t e n t i o n w i t h i n t h e f u e l c o a t i n g s up t o a b o u t 1600-1800째C, and w i t h o n l y l i m i t e d release up t o about 2000째C. The helium c o o l a n t does n o t undergo c h e m i c a l react i o n s w i t h i n t h e r e a c t o r c i r c u i t , and t h e use of a g a s c o o l a n t p r o v i d e s unambiguous c o o l a n t c o n d i t i o n s . Further, t h e l a r g e negative temperature c o e f f i c i e n t of r e a c t i v i t y f o r t h e f u e l makes f a s t - a c t i n g shutdown systems unnecessary.

F- 1

F- 2 N o n e t h e l e s s , i f t h e r e i s a complete l o s s of f o r c e d c o n v e c t i o n under d e p r e s s u r i z e d c o n d i t i o n s , t h e a f t e r h e a t g e n e r a t e d i n t h e c o r e would e v e n t u a l l y cause p l a n t damage and s i g n i f i c a n t f u e l p a r t i c l e c o a t i n g f a i l u r e s , s i n c e f u e l t e m p e r a t u r e s would rise t o v a l u e s g r e a t e r t h a n 2000째C. As a r e s u l t , e n g i n e e r e d s a f e t y systems are used t o supplement t h e i n h e r e n t c h a r a c t e r i s t i c s of t h e r e a c t o r and i n c l u d e t h e independent a u x i l i a r y c o o l i n g systems, independent and emergency r e a c t i v i t y shutdown systems, and t h e r e a c t o r containment b u i l d i n g .

REFERENCES FOR APPENDIX F

Gas-Cooled

Reactor Associates, HTGR Steam Cycle/ C o g e n e r a t i o n Lead P l a n t , Conceptual Design Summary Report, HCR-20101, February 1985. APPLIED TECHNOLOGY.

2230 MW(t)

APPENDIX G EVALUATION OF CLAIMS FOR THE MODULAR HIGH TEMPERATURE REACTOR (HTR)

T h i s appendix summarizes s a f e t y and economic claims which have been examined by NPOVS f o r t h e modular HTR.

Modular HTR S a f e t y C l a i m s The b a s i c s a f e t y claims of t h e modular HTR are: 0

d o s e s t o t h e p u b l i c w i l l not exceed v a l u e s which would r e q u i r e p u b l i c e v a c u a t i o n [ a c c o r d i n g t o E P A ' s P r o t e c t i v e A c t i o n Guideper p l a n t l i n e s (PAG)] t o a f r e q u e n c y of g r e a t e r t h a n 5 x year.

Meet t h e NRC i n t e r i m s a f e t y g o a l s .

F u r t h e r , t o a c h i e v e t h e s e g o a l s , a f i l t e r e d confinement, r a t h e r t h a n a c o n v e n t i o n a l containment i s s u f f i c i e n t .

A s s p e c i f i e d under R&D needs, S e c t i o n 3.5.3.1, term d a t a w i l l be needed t o assess t h i s claim.

a d d i t i o n a l source

R e l a t i v e t o investment p r o t e c t i o n , t h e c l a i m i s t h a t t h e cumulative frequency of e v e n t s l e a d i n g t o p l a n t l o s s i s l e s s t h a n 1 0 - 5 / p l a n t year. T h i s i s below t h e NPOVS c r i t e r i o n No. 2. 2.

Modular HTR Claims f o r Core Heatup A c c i d e n t s ( w i t h Scram) C i r c u l a t i n g a c t i v i t y and f i s s i o n product p l a t e o u t are s u f f i c i e n t l y low and f u e l performance d u r i n g normal o p e r a t i o n is s u f f i c i e n t l y good t h a t d o s e s can be m a i n t a i n e d below EPA's g u i d e l i n e s f o r p u b l i c e v a c u a t i o n i n c o r e heatup a c c i d e n t s so l o n g as t h e f u e l i s maint a i n e d below 1600 'C

To v e r i f y t h i s claim r e q u i r e s a d d i t i o n a l d a t a r e l a t i v e t o t h e s o u r c e term as is s p e c i f i e d i n t h e R&D needs, S e c t i o n 3.5.3.1 of t h i s report.

With l o s s of t h e main c i r c u l a t o r o r l o s s of c o o l i n g water flow t o t h e steam g e n e r a t o r , and w i t h l o s s of t h e a u x i l i a r y h e a t removal system, h e a t t r a n s p o r t t o t h e v e s s e l c o o l i n g system l i m i t s t h e f u e l I f t h e primary system i s d e p r e s s u r i z e d , t e m p e r a t u r e s t o 1200'C. h e a t t r a n s p o r t t o t h e v e s s e l c o o l i n g system l i m i t s f u e l temperat u r e s t o 1600'C. F u r t h e r , under n e i t h e r c i r c u m s t a n c e w i l l t h e r e be component damage.

G- 1

G-2

T h i s c l a i m is e s s e n t i a l l y s u p p o r t e d by s e v e r a l a n a l y s e s i n t h e United S t a t e s and West Germany. F u r t h e r s e n s i t i v i t y s t u d i e s are needed t o examine t h e impact of u n c e r t a i n t i e s i n v a r i o u s parameters on t e m p e r a t u r e s of f u e l and v e s s e l i n t e r n a l s . C.

With a l o s s of a l l a c t i v e and p a s s i v e e n g i n e e r e d c o o l i n g systems, There would h e a t t r a n s f e r t o t h e e a r t h l i m i t s t h e f u e l t o 1600째C. be component damage ( r e a c t o r v e s s e l and i n t e r n a l s ) . This i s dependent on s o i l p r o p e r t i e s and would r e q u i r e conf i r m a t o r y a n a l y s i s f o r e a c h site.

Modular HTR S a f e t y C l a i m s f o r T r a n s i e n t s w i t h o u t Scram

Although t h e c o r e i s provided w i t h h i g h l y r e l i a b l e p r i m a r y and reserve shutdown systems, r a p i d i n s e r t i o n of c o n t r o l material i s n o t r e q u i r e d f o r c o r e heatup t r a n s i e n t s i n v o l v i n g t h e f o l l o w i n g :

l o s s of c o o l i n g water flow t o t h e steam g e n e r a t o r , o

l o s s of f o r c e d c i r c u l a t i o n of helium,

depressurization.

For t h e s e e v e n t s which l e a d t o c o r e h e a t u p , t h e i n c r e a s e i n f u e l temp e r a t u r e s , combined w i t h t h e n e g a t i v e t e m p e r a t u r e c o e f f i c i e n t of react i v i t y drives the reactor subcritical. Peak t e m p e r a t u r e s d u r i n g t h e c o r e heatup are not s i g n i f i c a n t l y g r e a t e r t h a n w i t h scram. After s e v e r a l hours, depending on t h e s p e c i f i c thermal t r a n s i e n t c o n s i d e r e d , t h e f u e l w i l l have cooled s u f f i c i e n t l y and t h e xenon w i l l have decayed s u f f i c i e n t l y t o cause r e c r i t i c a l i t y . Evidence t h a t t h i s claim can be met f o r c o n d i t i o n s i n v o l v i n g l o s s of f o r c e d helium c i r c u l a t i o n i s provided by t e s t s which have been performed a t t h e AVR.l 4.

Modular HTR S a f e t y / I n v e s t m e n t P r o t e c t i o n C l a i m s f o r Water Ingress

Modular HTR proponents claim t h a t water i n g r e s s i s n o t a p u b l i c s a f e t y concern f o r t h e f o l l o w i n g r e a s o n s : e

t h e r e a c t i v i t y i n s e r t e d can be compensated by t h e c o n t r o l and shutdown s y s t e m s t h e chemical r e a c t i o n between water and g r a p h i t e i s a s e l f l i m i t i n g , endothermic r e a c t i o n

G-3

no flammable o r cornbustible g a s m i x t u r e w i l l be produced i n t h e confinement s i n c e t h e primary system s a f e t y r e l i e f v a l v e w i l l l i f t and d i s c h a r g e such g a s t h r o u g h p a r t i c u l a t e f i l t e r s and up a s t a c k i n t o t h e atmosphere

F u r t h e r , t h e claim i s made t h a t a l o n g o u t a g e would be p r e v e n t e d e i t h e r by a c t i v e e n g i n e e r e d systems ( m o i s t u r e m o n i t o r i n g , steam g e n e r a t o r i s o l a t i o n and dump), o r by a combination of t h e s e systems and o p e r a t o r actions. To examine t h e s a f e t y a s p e c t s of t h i s claim w i l l r e q u i r e computat i o n of t e m p e r a t u r e c o e f f i c i e n t s and c o n t r o l rod worth under c o n d i t i o n s of water i n g r e s s , computation of t h e r e a c t i v i t y i n s e r t i o n and i n s e r t i o n r a t e due t o water i n g r e s s , and a n a l y s i s of t h e r e s u l t i n g t h e r m a l transient. An a n a l y s i s of t h e chemical r e a c t i o n and i t s consequences s h o u l d a l s o be performed f o r t h e s p e c i f i c materials, geometry and assumed s e q u e n c e s of e v e n t s .

Modular HTR S a f e t y C l a i m s f o r A i r I n g r e s s

A s e r i o u s a i r i n g r e s s a c c i d e n t i s c o n s i d e r e d by p r o p o n e n t s t o be an extremely u n l i k e l y event (<5 x p e r r e a c t o r y e a r ) and t h u s i s n o t t r e a t e d as a d e s i g n b a s i s e v e n t . The claim i s t h a t e x c e s s i v e o x i d a t i o n of g r a p h i t e and r e s u l t a n t f i s s i o n product release can o c c u r o n l y i f t h e r e are r m l t i p l e r u p t u r e s i n t h e primary system, t h e r e i s no f o r c e d c o o l i n g , and much more t h a n one e n c l o s u r e volume of a i r reacts w i t h t h e graphite. I f t h e r e i s f o r c e d c o o l i n g c a p a b i l i t y , even w i t h a m i x t u r e of helium and a i r a t a t m o s p h e r i c p r e s s u r e , c o r e t e m p e r a t u r e s can be reduced t o 400째C i n a few hours. The r a t e of o x i d a t i o n a t 400째C and below i s v e r y low and no l o n g e r a s a f e t y concern. F i n a l l y , with a l a r g e a i r i n g r e s s , t h e h e a t g e n e r a t i o n by o x i d a t i o n i s very small r e l a t i v e t o decay h e a t g e n e r a t i o n , so c o r e t e m p e r a t u r e s are n o t e x p e c t e d t o be s i g n i f i c a n t l y g r e a t e r than f o r a depressurized core heatup accident.

To examine t h e l i c e n s i n g a s p e c t s of an a i r i n g r e s s e v e n t , i t may be n e c e s s a r y t o d e t e r m i n e t h e r i s k a s s o c i a t e d w i t h a i r i n g r e s s and t o comp a r e t h a t r i s k w i t h t h e t o t a l r i s k from normal o p e r a t i o n of t h e p l a n t . To examine t h e consequences of a i r i n g r e s s r e q u i r e s a n a l y t i c a l model development ( c u r r e n t l y i n p r o g r e s s ) f o r a c c i d e n t s i m u l a t i o n , an unders t a n d i n g of t h e g a s exchange between t h e primary system and t h e c o n f i n e ment and a thorough u n d e r s t a n d i n g of t h e o x i d a t i o n p r o c e s s . Further p r o v i s i o n s i n t h e confinement t o l i m i t a i r a c c e s s i b i l i t y should be examined f o r p r a c t i c a l i t y .

Economics and C o n s t r u c t i b i l i t y C l a i m s

Claim. T o t a l power g e n e r a t i o n c o s t s are c o m p e t i t i v e w i t h c o a l a* p l a n t s of e q u a l c a p a c i t y . *

G-

Evaluation. Because of t h e p r e l i m i n a r y c o n c e p t u a l n a t u r e of t h e d e s i g n , t h e r e are l a r g e u n c e r t a i n t i e s , e s p e c i a l l y i n c a p i t a l i n v e s t m e n t costs. C e r t a i n l y , i t can be claimed t h a t t h i s c o n c e p t h o l d s s i g n i f i c a n t promise t o be c o m p e t i t i v e . Design and c o s t s t u d i e s s h o u l d c o n t i n u e t o b e t t e r d e f i n e t h e economic c o m p e t i t i v e n e s s w i t h c o a l . It i s recommended t h a t s t u d i e s be c a r r i e d o u t t o p r o v i d e improved c a p i t a1 c o s t es t i m a t es by :

(1)

Continued development of t h e d e s i g n t o t h e p o i n t t h a t q u a n t i t i e s of commodities and l a b o r can be e s t i m a t e d and compared w i t h c u r r e n t LWR and c o a l - f i r e d p l a n t e x p e r i e n c e .

(2)

Development of estimates of i n d i r e c t c o s t s (e.g., manhours o f d e s i g n e n g i n e e r i n g and p r o j e c t management, i n s t e a d of r e l y i n g on percentages).

(3)

S t a r t i n g with a "first-of-a-kind" plant, development of s t r a t e g y f o r a r r i v i n g a t t h e c o s t of an "Nth-of-a-kind plant.

b. Claim. S i g n i f i c a n t c a p i t a l investment c o s t savings a c h i e v e d through use of a c o n f i n e m e n t , r a t h e r t h a n c o n t a i n m e n t .

the

are

Evaluation. B e c h t e l made a s t u d y i n FY 1982 (Ref. 4 ) i n which t h e added d i r e c t c o s t f o r containment f o r a modular HTR p l a n t w i t h 8 r e a c t o r s w a s e s t i m a t e d t o be $70 x l o 6 . E s c a l a t i o n t o 1985 and a d d i t i o n of i n d i r e c t c o s t s i n c r e a s e s t h i s amount t o a b o u t $120 x l o 6 o r $150/ kW(e), which i s a s i g n i f i c a n t c o s t .

c. C l a i m . Systems o u t s i d e t h e n u c l e a r i s l a n d can be p r o c u r e d and i n s t a l l e d t o non-nuclear s t a n d a r d s r e s u l t i n g i n an o v e r a l l s a v i n g s i n c a p i t a l i n v e s t m e n t c o s t of a p p r o x i m a t e l y 10% (Ref. 5 ) . Evaluation. It has been documented6y7 t h a t t h e c o s t of non-nuclear The p o r t i o n s of LWR p l a n t s i s much h i g h e r t h a n f o r c o a l - f i r e d p l a n t s . r e a s o n s c i t e d a r e as f o l l o w s : 0

N u c l e a r q u a l i t y s t a n d a r d s a f f e c t t h e a t t i t u d e s of a l l p e r s o n s working on t h e e n t i r e p r o j e c t - management, e n g i n e e r i n g , and crafts.

Bulk materials f o r t h e e n t i r e b o l t s , embedments, small bore cured and handled as r e q u i r e d program t o e l i m i n a t e danger safety-related s t r u c t u r e s and stitution.

Non-safety s t r u c t u r e s a d j o i n i n g s a f e t y - r e l a t e d s t r u c t u r e s are d e s i g n e d t o p r e v e n t c o l l a p s e i n t h e e v e n t of a d e s i g n b a s i s earthquake o r tornado.

p r o j e c t , such as r e b a r , anchor p i p i n g , and c o n c r e t e , are proby a n u c l e a r q u a l i t y a s s u r a n c e of d e g r a d i n g t h e q u a l i t y of systems by i n a d v e r t e n t sub-

G- 5

Management and s u p e r v i s i o n are p r e o c c u p i e d w i t h problems associated with safety-related f a c i l i t i e s and o f t e n n e g l e c t p l a n n i n g f o r non-sa f e t y f a c i 1 i t i es

B e c h t e l a d d r e s s e s t h e s e problems by p r o p o s i n g t o p r o v i d e p h y s i c a l separ a t i o n between t h e n u c l e a r and non-nuclear f a c i l i t i e s and between t h e c o n s t r u c t i o n f o r c e s so t h a t t h e low p r o d u c t i v i t y e x p e r i e n c e d i n n u c l e a r c o n s t r u c t i o n i s n o t t r a n s f e r r e d t o t h e non-nuclear a r e a s . Our a n a l y s i s a s a p p l i e d t o c u r r e n t T,WRs c o n f i r m s t h e 10% l e v e l of s a v i n g s i n i n v e s t ment c o s t . 8 However, t h e r e a r e a l s o r e a s o n s why t h e s e s a v i n g s may n o t be f u l l y r e a l i z e d : e

D i s p e r s i o n of p l a n t f a c i l i t i e s w i t h l o n g e r r u n s f o r p i p i n g and w i r i n g and c a b l e s .

Duplication facilities.

construction

management

and

construction

The e n t i r e q u e s t i o n of s e p a r a t i o n of f a c i l i t i e s t o a c h i e v e i n c r e a s e d l a b o r p r o d u c t i v i t y i s a l s o a management i s s u e . For example, a few U.S. u t i l i t i e s have been a b l e t o b u i l d LWK p l a n t s w i t h about one-half t h e R&D should be d i r e c t e d toward l a b o r c o n t e n t of t h e a v e r a g e L'VR p l a n t . 7 d e t e r m i n i n g how b e s t t o manage and o r g a n i z e n u c l e a r c o n s t r u c t i o n projects t o assure higher labor productivity. S e p a r a t i o n of c o n s t r u c t i o n i s one o r g a n i z a t i o n a l a p p r o a c h t o promoting b e t t e r management. Claim. A v a i l a b i l i t y can exceed 80% w i t h f u t h e r d e s i g n improved. ments. Use of two o r f o u r t u r b i n e g e n e r a t o r sets c o u l d i n c r e a s e a v a i l ability. E v a l u a t i o n . HTK Program a v a i l a b i l i t y s t u d i e s are c o n t i n u i n g i n t h e DOE program. Achievement of such v a l u e s depends upon t h e unscheduled o u t a g e s which w i l l o c c u r , as w e l l as on r e f u e l i n g and s c h e d u l e d o u t a g e times. E s t i m a t e s of unscheduled o u t a g e s and r e f u e l i n g times are u n c e r t a i n in our e v a l u a t i o n ; w h i l e >80% a v a i l a b i l i t y a p p e a r s t o be a c h i e v a b l e ( s e e below), i t cannot be a s s u r e d a t t h i s t i m e . The North American E l e c t r i c R e l i a b i l i t y Council (NEKC) Equipment A v a i l a b i l i t y Report f o r t h e 10-year p e r i o d 1 9 7 4 4 9 8 3 s u p p o r t s t h e claim of smaller t u r b i n e g e n e r a t o r s c o n t r i b u t i n g t o h i g h e r o v e r a l l p l a n t availability. As shown i n T a b l e 3 . 4 of Volume 111, f o s s i l p l a n t t u r b i n e - g e n e r a t o r s e t s i n 400 MW(e) and below s i z e s have d i s t i n c t l y lower f o r c e d and s c h e d u l e d o u t a g e rates and h i g h e r a v a i l a b i l i t i e s t h a n turbine-generator sets i n the l a r g e r sizes. The a d v a n t a g e i s even more s i g n i f i c a n t â&#x201A;Ź o r n u c l e a r p l a n t t u r bine-genera t o r sets b e l ow 80O-Mw( e ) s i z e , compared w i t h t h o s e above 800 MW(e). It a l s o i s observed t h a t sets have a d i s t i n c t performance nuclear plant turbine-generator a d v a n t a g e over f o s s i l sets i n a l l s i z e ranges. It is s p e c u l a t e d t h a t t h i s may be due t o t h e lower steam t e m p e r a t u r e s and p r e s s u r e s and r o t a t i o n a l s p e e d s of n u c l e a r t u r b i n e - g e n e r a t o r sets, which r e s u l t i n a less s e v e r e o p e r a t i n g environment.

G- 6

A s shown i n Table 3.5 of Volume 111 t h e area having t h e g r e a t e s t reactor p o t e n t i a l f o r LWR p l a n t a v a i l a b i l i t y improvement i s w i t h t h e It i s obvious t h a t p l a n t a v a i l a b i l i t y improveand a s s o c i a t e d systems. ment R&D must c o n c e n t r a t e on t h e r e a c t o r and i t s r e l a t e d s y s t e m s . For example, a 50% r e d u c t i o n i n r e a c t o r scheduled o u t a g e f a c t o r p l u s a 50% r e d u c t i o n i n r e a c t o r f o r c e d o u t a g e rate would r e s u l t i n 80% o v e r a l l plant equivalent a v a i l a b i l i t y . The above LWR d a t a p r o v i d e s s t r o n g s u p p o r t t h a t t h e modular HTR g o a l can be achieved.

A four-module p l a n t can be c o n s t r u c t e d i n 36 months e* C l a i m . from s t a r t of s i t e work t o commercial o p e r a t i o n of t h e second t u r b i n e . 2

Evaluation. T h i s is an o p t i m i s t i c s c h e d u l e when judged by U.S. e x p e r i e n c e , but a p p e a r s p o s s i b l e . The modular HTR s c h e d u l e i s based on It should be rea n e v a l u a t i o n of t h e c o n c e p t u a l d e s i g n by F k c h t e l . examined a f t e r t h e d e s i g n has been c a r r i e d t o p o i n t of e s t i m a t i n g quant i t i e s of c o n s t r u c t i o n m a t e r i a l s ( s t r u c t u r a l s t e e l , c o n c r e t e , p i p i n g , and w i r i n g , ) and l a b o r manhours. This w i l l p r o v i d e a firmer b a s i s f o r e s t i m a t i n g e l a p s e d t i m e f o r p l a c i n g equipment and materials. The c o n s t r u c t i o n s c h e d u l e should be r e e v a l u a t e d as t h e d e s i g n p r o g r e s s e s . f.

Claim.

The p l a n t can be o p e r a t e d and m a i n t a i n e d by a s t a f f of

306 (Ref. 2). Evaluation. T h i s estimate is based on a p r e l i m i n a r y a n a l y s i s of In comparison, t y p i c a l s t a f f i n g f o r c u r r e n t s t a f f i n g requirements. l a r g e UJR p l a n t s i s -400. The modular HTR s t a f f i n g estimate i s based on t h e f o l l o w i n g assumptions:

R e g u l a t o r y p r o c e d u r e s have been f i t t i n g by maintenance f o r c e s ) .

stabilized

(i.e.

back-

P l a n t c o n t r o l is h i g h l y automated, p e r m i t t i n g f o u r r e a c t o r s by one c o n t r o l o p e r a t o r s t a t i o n .

P l a n t i s designed f o r maintenance w i t h one module o f f l i n e res u l t i n g i n minimum r e q u i r e m e n t s f o r peak maintenance f o r c e s .

P l a n t s e c u r i t y i s h i g h l y automated, r e q u i r i n g minimum s e c u r i t y forces.

o p e r a t i o n of

These a s s u m p t i o n s , a l o n g w i t h t h e smaller t u r b i n e - g e n e r a t o r s i z e r e q u i r i n g less maintenance p e r s o n n e l , are t h e p r i n c i p a l r e a s o n s f o r t h e reduced s t a f f i n g . F u r t h e r s t u d i e s of o p e r a t i o n and maintenance s t a f f i n g should be performed, u s i n g a t a s k - a n a l y s i s approach, e s p e c i a l l y i n t h e area of c o n t r o l o p e r a t i o n of m u l t i p l e r e a c t o r s by a s i n g l e c o n t r o l opera t i o n and i t s r e l a t i o n t o s a f e t y .

Claim. Adding c a p a c i t y i n small i n c r e m e n t s i s / w i l l be a gs i g n i f i c a n t E i n a n c i a l goal of u t i l i t i e s and r e s u l t s i n less f i n a n c i a l risk.

G- 7

Evaluation. I n a t i m e p e r i o d of low l o a d growth, h i g h f i n a n c i n g and c o n s t r u c t i o n c o s t s , and r e l u c t a n c e of p u b l i c u t i l i t y commissions t o g r a n t rate a d j u s t m e n t s , t h i s claim a p p e a r s i n t u i t i v e l y obvious. Two r e c e n t d r a f t s t u d i e s by Los Alamos N a t i o n a l L a b o r a t o r y (LANL) and Applied D e c i s i o n A n a l y s i s 8 , s u p p o r t t h i s claim. Both s t u d i e s a t t e m p t e d t o q u a n t i f y t h e a d d i t i o n a l c a p i t a l investment c o s t t h a t u t i l i t i e s could a f f o r d t o pay f o r smaller, s h o r t e r l e a d time p l a n t s i n comparison w i t h l a r g e r , l o n g e r l e a d t i m e p l a n t s , w h i l e c o n t i n u i n g t o meet t h e i r financial goals. LANL found t h a t a r e d u c t i o n from l o n g t o medium l e a d tiines p e r m i t s t h e u t i l i t y company t o pay 40-50% more i n o v e r n i g h t c o n s t r u c t i o n c o s t s , and a r e d u c t i o n from long t o s h o r t l e a d times permits a four-fold increase i n the overnight construction cost. From a r a t e p a y e r v i e w p o i n t , Boyd e t found t h a t u t i l i t i e s could pay approxi m a t e l y $200/kW(e) c a p i t a l investment c o s t premium f o r smaller u n i t s i z e s and s h o r t e r l e a d times f o r u t i l i t y system s i z e s 3000 MW(e) and larger. From t h e s h a r e h o l d e r viewpoint, t h e a f f o r d a b l e c a p i t a l i n v e s t ment c o s t premium was found t o be two t o t h r e e times h i g h e r t h a n from t h e r a t e p a y e r viewpoint. The f i n d i n g s a r e g e n e r a l i n t h a t t h e y a p p l y t o any type of power p l a n t , they are a l s o s e n s i t i v e t o a number of p a r a m e t e r s (e.g., system s i z e , e x i s t i n g g e n e r a t i o n m i x , l o a d growth r a t e , and f i n a n c i n g ) . However, s e n s i t i v i t y a n a l y s e s i n both s t u d i e s e recommend, however, t h a t t h e s t u d i e s i n t h i s area s u p p o r t t h e claim. W be c o n t i n u e d and r e f i n e d t o d e v e l o p a complete u n d e r s t a n d i n g of t h e economics of small n u c l e a r p l a n t s .

G- 8

REFEKENCK3 FOR APPENDIX G 1.

K. J. KrGger and G. P. Ivens, “ S a f e t y - r e l a t e d E x p e r i e n c e s w i t h t h e AVR-Reactor,” p r e s e n t e d a t t h e IAEA S p e c i a l i s t s ’ Meeting on S a f e t y and Accident A n a l y s i s f o r Gas-Cooled R e a c t o r s , Oak Ridge, Tennessee, May 13-15, 1985.

P r e l i m i n a r y Concept D e s c r i p t i o n Report, 4 x 250 ElW(t) HTGR P l a n t Side-by-Side S t e e l Vessel P r i s m a t i c Core Concept, HTGR-85-142, e t a l . , f o r Gas-Cooled R e a c t o r i s s u e d by B e c h t e l Group, Inc., Associates, San Diego, California, October 1985. AP PL I E U TECHNOLOGY.

HTGK Program Concept E v a l u a t i o n P l a n f o r Small HTGRs, GCRA 84-009, Gas-Cooled Reactor A s s o c i a t e s , San Diego, C a l i f o r n i a , October 31, 1984.

Modular HTGR Balance of P l a n t Design and Cost S t a t u s R e p o r t , Bechtel Group, Inc., San F r a n c i s c o , C a l i f o r n i a , September 1982.

Modular

C o n s t r u c t i b i l i t y Assessment f o r Modular High-Temperature Gas-Cooled R e a c t o r s , Bechtel Group, Inc., San F r a n c i s c o , C a l i f o r n i a , .July 1982.

Phase IV Update of t h e EEDB, DOE/NE-0051/1, United E n g i n e e r s and C o n s t r u c t o r s , Inc., P h i 1ade 1p h i a , Pennsyl v a n i a , Septelnber 1984.

Andrew Ford, The Market € o r New Electric G e n e r a t i n g Capacity: A F i n a n c i a l F e a s i b i l i t y Case Study, Los Alamos N a t i o n a l L a b o r a t o r y , Los Alamos, New Nexico, June 1984.

D. W. Boyd e t a l . , The P o t e n t i a l Impact o€ M o d u l a r i t y vs. U t i l i t y G e n e r a t i o n Investment D e c i s i o n s , D e c i s i o n Focus, Inc. and Applied D e c i s i o n A n a l y s i s , Inc., f o r t h e E l e c t r i c Power Research I n s t i t u t e , P a l o A l t o , C a l i f o r n i a , March 1984.

HTGR System Design and C o s t Suminary, (;CFR-00693, Group, Inc., San F r a n c i s c o , C a l i f o r q i a , September 1983.

Bechtel

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1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15-16. 17. 18. 19. 20-24. 25. 26.

E. T. S. J. R. H. R. J. W. R. J. T. W. R. J. H. G. C. U. P. D.

D. D. J. T. S. I. B. R. D. A. C. E. G. M. G. L. F.

Aebischer Anderson Ball Bell Booth Bowers Braid Buchanan Burch Cantor Cleveland Cole Craddick Davis Delene Dodds, Jr. Flanagan W. Forsberg Gat M. Haas C. Hampson

27. 28. 29. 30. 31-47. 48. 49. 50. 51. 52. 53. 54-73. 74* 75. 76-93. 94. 95. 96. 97. 98-99. 100.

J. E. Jones Jr. P. R. Kasten F. A. D. F. L.

C. Maienschein P. Malinauskas L. Moses R. Mynatt C. Oakes S. Rayner T. H. Row D. L. Selby H. E. Trammel1 D. B. Trauger R. E. Uhrig D. K. Wehe J. D. White T. J. Wilbanks R. G. Wymer Central Research Library Document Reference Section Laboratory Records Department Laboratory Records (RC)

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101. Office of Assistant Manager for Energy Research and Development, ORO, DOE, Oak Ridge, TN 37831. 102-177. Distribution Category UC-79T, Liquid Metal Fast Breeder Reactors: Applied Technology. 178-283. Nuclear Power Options Viability Study Distribution.

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