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ORNL-TM-1997

C o n t r a c t No. W-7405-eng-26

MFPALS AND CERAMICS DIVISION

AN EVALUATION OF THE MOLTEN SALT REACTOR

EXPERIMENT

HASTELLOY N SURVEILLANCE SPECIMENS - FIRST GROUP

NOVEMBER 1967

OAK RIDGE NATIONAL LABORATORY Oak R i d g e , Tennessee operated by UNION CARBIDE CORPORATION f o r the U.S. ATOMIC ENERGY COMMISSION

THlS EOCUMENf Is

iii

........................... Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . Experimental Details . . . . . . . . . . . . . . . . . . . . . Surveillance Asseuibly . . . . . . . . . . . . . . . . . . &terials . . . . . . . . . . . . . . . . . . . . . . . . . Test Specimens . . . . . . . . . . . . . . . . . . . . . . Irradiation Conditions . . . . . . . . . .-. . . . . . . . Testing Techniques . . . . . . . . . . . . . . . . . . . . Test Results . . . . . . . . . . . . . . . . . . . . . . . Discussion of Results . . . . . . . . . . . . . . . . . . . . Summary and Conclusions . . . . . . . . . . . . . . . . . . . Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .

Abstract

Page 1 1

2 4 4 6 8 9

49 52

AN EVALUATION OF THE MOLTENSALT REACTOREXPERIMENT HASTELLOYNSURVEILLANCESPEK!IMENS-FIRSTGROUP H.'E.

McCoy, Jr.

ABSTRACT We have tested the first group of surveillance specimens from the Molten Salt Reactor Experiment,core. They were removed after 7823 Mwhr of reactor operation during which the specimens were held at 645 + 1O'C for 4800 hr and accumulated a thermal dose of 1.3 x 102' neutrons/cm2. The high-temperature ductility was reduced, but the reduction was similar to that observed for these materials when irradiated in the Oak Ridge Reactor in a helium environment. The low-temperature ductility was reduced, and this is thought to be due to the formation of intergranular MeC. The specimens showed no evidence of corrosion; however, a carbon-rich layer, 1 to 2 mils in depth, was noted where the Hastelloy N and graphite were in contact. The mechanical properties of the Hastelloy N appear adequate for the continued satisfactory operation of the MSRE. Test results are presented for the effects of several variables on the tensile ductility of irradiated and unirradiated Hastelloy N. These variables included test temperature, strain rate, and prestraining.

INTRODUCTION

The Molten Salt Reactor Experiment is a single region reactor that is fueled by a molten fluoride salt (65 LiF, 29.1 BeF2, 5 ZrF4, and contained by Hastelloy 0.9 UF4 mole $), moderated by unclad graphite,

(Ni-16 MO-7 Cr-4 Fe-O.05 C, â&#x20AC;&#x2DC;w-t $). The details of the reactor design and We knew that the neutron environment construction can be found elsewhere.' - graphite and would produce some changes inthe two structural , I -I_._.. .materials . of these Hasteiloy N. Although we were very confident of the compatibility L 'R. C. Robertson, MSRE Design and Operations of Reactor Design, ORNL-TM-728 (January 1965).

t .

Report,

Pt.

1, Description

2 materials with the fluoride s a l t , we needed t o keep abreast of t h e possible

development of corrosion problems within the reactor i t s e l f .

For these reasons, we developed a surveillance program t h a t would allow us t o follow the property changes of graphite and Hastellcry N specimens as the reactor operated. The reactor went c r i t i c a l on June 1, 1965, and a f t e r numerous

small problems were solved, assumed normal operation on Mziy 1966.

The

present group of surveillance specimens was i n the reactor from Septeuiber 8, 1965, t o July 28, 1966, and was removed a f t e r 7823 Mwhr of operation (designated "first group").

This report covers t h e tests t h a t

were run on Fhe Hastelloy N specimens t h a t were removed.

Surveillance Asseuibly' The core surveillance assembly was designed by W. H. Cook and others,

and t h e d e t a i l s have been reported previously.2

The f a c i l i t y i s shown

p i c t o r i a l l y and schematically i n Fig. 1. The specimens are arranged i n three stringers. Each stringer i s about 62 in. long and consists of t w o Hastelloy N rods and a graphite section made up of various pieces that are. Y

joined by pinning and tongue-and-groove joints.

The Hastelloy N rod has periodic reduced sections 1 1/8 in. long x 1/8 in. i n diameter and can be

4, k

cut i n t o small t e n s i l e specimens after it i s removed f r o m t h e reactor. Three stringers are joined together so t h a t they can be separated i n a hot c e l l and reassembled with one o r more new stringers f o r reinsertion i n t o the reactor.

The assernbled stringers f i t i n t o a perforated Hastelloy N

basket t h a t i s inserted i n t o an a x i a l position about 3.6 in. f r o m t h e core center line.

*W. H. Cook, MSR Program Semiann. Progr. Rept. Aug. 31, 1965, ORNL-3872, p. 87.

BT PHOTO et671

( Fig. 1. MSRE Surveillance Fixture,

R = REMOVABLE STRINGER

II)

When the basket was removed on July 18, 1966, some of the specimens were bent and the e n t i r e assenibly had t o be replaced.3

Slight modifications

'in the design were made, and the assembly was removed recently and found $0

be i n excellent condition. A control f a c i l i t y i s associaCed with the surveillance program.

u t i l i z e s a "fuel s a l t " containing depleted uranium i n a s t a t i c pot t h a t i s heated e l e c t r i c a l l y .

The temperature i s controlled by the HRE computer so

t h a t the temperature matches that of the reactor.

Thus, these specimens

a r e exposed t o conditions the same as those i n the reactor except f o r t h e s t a t i c s a l t and t h e absence of a neutron flux. There i s another surveillance f a c i l i t y for Hastelloy N located outside the core i n a v e r t i c a l position about 4.5 in. f r o m t h e vessel. specimens are- exposed t o the c e l l environment (N2

+ 2-54

02).

These

They were

not 'removed during the first group. lkterials

Two heats of Hastellay N were used i n t h i s program: heats 5081 and 5085. Both of these heats were air-melted by S t e l l i t e Division of Union Carbide Corporation, and their chemical analyses a r e given i n Table 1, Heat 5085 w a s used for making the cylindrical portion of t h e core vessel,

and heat 5081 was used for various p a r t s inside the reactor.

I Y

Test Specimens The specimens were put i n t o t h e reactor as rods 62 i n . long by 1/4 in. i n diameter with reduced sections 1/8 in. i n diameter by 1 1/8 in. long. 'The long rod was made i n seven pieces and welded together \

t o obtain the 62-in.-long rod.

After removal f r o m t h e reactor, the rod

was sawed i n t o small specimens with a gage section 1 l/8 in: long by

1/8 in. i n diameter.

Each rod i s designated by a l e t t e r and the individual

%. H. Cook, MSR Program Semiann. Progr. Rept. Aug. 31, 1966, ORNL-4037, p. 97. Ann.

%. H. Cook, "Molten Salt Reactor Program," Metals and Ceramics Div. Prom. Rept. June 30, 1967, ORNL-4170, Chap. 34 ( i n press).

U e

. 5

Table 1. Chemical Analysis of Surveillance Heats 'content, w t Element Heat 5085

Heat 5081

6.2

6.1

3.3

3.4

16.3

16.4

0.054

0.58

0.15

0.10

0.07

0.67

0.65

0.20

P S

0.013

0.012

0.004

0.002

0.02

0.05

4.01

43.01

0.01

0.0038

0.0050

bal

0.059 I

0.52

--.

w* specimens are numbered beginning a t the bottom of t h e rod and increasing t o 27 a t the top. The rods i n t h e first group were bent, and it was necessary t o examine

each specimen with an optical comparator t o determine whether it was

If’the t o t a l indicated runout of the gage section was greater than 0.002 in., t h e specimen was not used. The best specimens were used f o r the higher temperature t e s t s where the expected s t r a i n s were smallest. The results from a b r i t t l e material are affected more seriously by specimen alignment than are those from a d u c t i l e material. suitable‘for use.

The materials were received i n the m i l l annealed condition (lhr a t They were given a M h e r anneal of 2 h r a t 900°C p r i o r t o

1177°C).

insertion i n t o the reactor and t h e control f a c i l i t y . s

Irradiation Conditions The specimens from the first group were i n the reactor from . September 8, 1965, t o July 28, 1966.

The reactor had operated 0.0066 &hr

when the specimens were inserted and 7823 Mwhr when they were removed. They were at temperature f o r 4800 h r w i t h the temperature range being 645 f 10°C.

Huwever, t h e material was only exposed t o s a l t f o r 2796 hr,

The f l u x was measured by H. B. Piper5 using s t a i n l e s s s t e e l wires t h a t were attached t o the surveillance specimens.

p r o f i l e s a r e shown i n Figs. 2 and 3 along with t h e a x i a l location of each specimen.

The thermal and fast f l u x k

The peak thermal dose, based on the 59Co(n,7)60Co transmutation,

lo2’

was 1.3 X

neutrons/cm2 and t h e fast dose (>1.22 Mev), based on the

58Ni(n,p) 58Co transmutation, was 3 X

lo1’

neutrons/cm2.

The cross section

used f o r t h e 59Co(n,7)60Co transmutation was 22.25 barns, and that f o r the 58Ni(n,p)58Co transmutation was 0.1262 barns. 5H. B. Piper, private commication.

7 ORNL-DWG

67-7932

NEUTRON

MTL ENERGY

REACTION <0.876 eV 58Fe(n.y)5sFe <0.876 eV 59C~(n.7)60Co <0.876 eV 58Fe(n,y)5sFe EXPOSURE-7823 MW-hr

A Fe 0

SS SS

inches

Fig. 2. Measurements of the Thermal Flux for the NSRE Core Specimens -First Group.

ORN L- OW0 67-7933

MTL Fe 0 SS 0 SS

1.4

1.2

ENERGY

> 2.02 MeV 54Fe(n,p) 54Mn

> 4.22 MeV 5eNi(n,p)58Co > 2.02 MeV 54Fe(n,p)58Mn EXPOSURE

- 7823 MW-hr

0.8

0.6

0.4

0.2

inches \

Fig. 3. Measurements of the Fast Flux for the MSRE Core Specimens First Group.

8 Testing Techniques The laboratory creep-rupture tests were run i n conventional creep

machines of the dead load and lever arm types.

The s t r a i n was measured by

a d i a l indicator t h a t shared the t o t a l movement of the specimen and part of the load t r a i n .

The zero s t r a i n measurement was taken immediately a f t e r

the load was applied.

The temperature accuracy was *0.75$, the guaranteed

accuracy of t h e Chromel-P-Alumel thermocouples used. The postirradiation creep-rupture t e s t s were run i n lever arm machines t h a t were located i n hot c e l l s . The s t r a i n was measured by an extensometer with rods attached t o the upper and lower specimen grips. The r e l a t i v e .

movement of these two rods was measured by a l i n e a r d i f f e r e n t i a l t r a n s former, and the transformer signal was recorded. measurements i s d i f f i c u l t t o determine.

The accuracy of t h e s t r a i n

The extensometer (mechanical and

e l e c t r i c a l portions) produced measurements that could be read t o about

&0.02$ s t r a i n ; however, other factors (temperature changes i n t h e c e l l , mechanical vibrations, etc.) probably combined t o give an overall accuracy of k0. I$ s t r a i n .

This i s considerably better than the specimen-to-specimen

reproducibility t h a t one would expect for r e l a t i v e l y b r i t t l e materials. !he temperature measuring and control system was the same a s t h a t used i n the laboratory with only one exception.

I n t h e laboratory, t h e control

system was stabilized a t t h e desiredtemperature by use of a recorder with an expanded scale.

I n the tests i n t h e hot c e l l s , the control point was

established by s e t t i n g the controller without the a i d of the eaanded-scale recorder.

This e r r o r and the thermcouple accuracy combine t o give a

temperature uncertainty of about *l$. The t e n s i l e t e s t s were run on Instron Universal Testing Machines.

The

s t r a i n measurements were taken from the crosshead travel. The t e s t environment was a i r i n a l l cases.

Metallographic examination

showed t h a t the depth of oxidation was small (4.002 in.), and hence we f e e l t h a t the environment did not appreciably influence the test r e s u l t s .

LJ I

c I

T e s t Results

Since the surveillance assembly was b nt, it w a s necessary t

remove

a l l t h e specimens i n t h e first group, and we had about 50 specimens of each heat a f t e r - t h e bent ones were discarded.

Thus, we had enough specimens

t o run t h e desired t e s t s f o r surveillance purposes and enough t o look a t

some f u r t h e r variables t h a t a r e of value i n understanding t h e behavior of. i r r a d i a t e d Hastelloy N.

We s h a l l present a l l the r e s u l t s t h a t were obtained

even though much of t h i s idormation has l i t t l e d i r e c t bearing on t h e s a f e operation of t h e l43RE.

Since the rupture d u c t i l i t y i s of primary impor-

tance, we shall be most concerned w i t h t h i s property. The results of t e n s i l e t e s t s on t h e control specimens of heat 5081 a r e given i n Table 2.

The t o t a l elongations a t f r a c t u r e as a function of

temperature a r e shown i n Fig. 4 f o r s t r a i n rates of 0.05 and 0.002 min-l. This material exhibits t h e d u c t i l i t y minimum t h a t i s c h a r a c t e r i s t i c of

nickel-base alloys.

The temperature of the minimum d u c t i l i t y seems t o

decrease w i t h decreasing s t r a i n rate.

Several of t h e specimens were run

a t various s t r a i n rates over the range of 2 t o 0.002 min”.

The results

of these t e s t s a r e a l s o given i n Table 2, and t h e f r a c t u r e elongations are given i n Fig. 5.

The f r a c t u r e elongation i s very s e n s i t i v e t o s t r a i n rate

a t 650”C, but r e l a t i v e l y insensitive a t higher and lower temperatures. The r e s u l t s o f , t h e tests on t h e surveillance specimens from heat 5081

a r e summarized i n Table 3,

The elongation a t f r a c t u r e i s p l o t t e d as a

function of temperature i n Fig. 6. The irradiated material i s characterized by a sharp drop i n d u c t i l i t y with increasing temperature above about 500°C. The d u c t i l i t y continues t o decrease with increasing temperature r a t h e r than exhibiting a d u c t i l i t y minimum like t h e unirradiated material (Fig. 4). The d u c t i l i t y i s lower a t a s t r a i n r a t e of 0.002 min” than a t 0.05 min-l, but t h e difference decreases with increasing temperature. demonstrated quite w e l l i n

This point i s

i g . 7 where the dependence of the d u c t i l i t y on

s t r a i n rate i s shown f o r several temperatures. We have looked individually a t t h e properties of t h e surveillance and control specimens of heat 5081; l e t us now compare these properties.

The

r a t i o s of t h e property f o r t h e i r r a d i a t e d material t o t h a t of t h e unirradiated material a r e compared i n Fig. 8 as a function of temperature.

Table 2.

Specimen Number

("C)

0.05

47,700

llS,700

55.9

57.6

48.8

67.4

.AC-11

200

0.05

40,200

l07,100

53.3

54.6

42.0

58.9

CC-27 CC-26 CC-25 AC-22 CC-24 CC-23 BC- 8

400 400

.coo

2 0.5 0.2 0.05 0.02 0.005 0.002

41,400 34,600 36,300 36,700 37,800 34,700 37,100

94,500 97,000 97,900 100,600 99,900 97,400

50.4 53.7 52.2 51.0 51.7 55.4 52.9

53.6 58.2 53.8 52.0 56.0 ' 56.3 55.2

42.4 46.6 42.7 48.7 41.7 44.0 46.7

cc-21 CC-19 CC-29 CC-18 AC-19 CC-17 CC-16 AC-24 BC-9

500 500 500 500 500 500 500 500 500

2 2 0.5 0.2 0.05 0.02 0.005 0.002 0.002

36,200 35,200 52,600 36,800 35,800 34,900 34,700 35,000 36,200

93,200 92,700 105,400 98,800 97,800 97,600 92,500 97,700 95,300

52.0 52.4 45.8 55.0 53.6 . 55.5 54.4 44.9 46.2

56.0 56.0 49.4 57.0 56.6 56.6 55.4. 45.3 47.0

48.8 42.6 40.5 51.1 46.2 46.2 40.3 33.6 38.1

67.4 55.8 52.0 72.0 62.0 62.5 51.6 41.0 48.2

AC-20 AC-25

550 550

0.05 0.002

35,900 37,300

93,300 80,300

49.7 22.8

51.1 23.7

40.3 23.0

51.8 26.2

AC-18 AC-29

600 600

0.05 0.002

34,900 37,400

81,200 71,400

31.8 21.3

32.3 21.7

31.0 19.9

37.2 22.4

400

400 400 400

Street3 ( p s i ) Yield Ultimate

Elongation ($1 Uniform Total

Strain Rate (min-l)

AC-8

Test Temperature

Results of T e n s i l e Tests on IBRE S u r v e i l l a n c e Control Specimens Heat 5081 Reduction i n Area

($1

True Fracture Strain (Q)

55.7 63.1 56.0 66.8 54.4 58.6 63.0

I-'

Table 2 (continued)

Specimen Number

Test Temperature ($1

Strain' Rate (min-l)

Stress (psi) Piem Ultimate

Elongation ($) Uniform Total

Reduction i n Area

True Fracture Strain

($1

52.4 46.8 39.0 29.3 24.6 17.7 23.1 23.2

36.9 37.2 28.8 23.4 23.1 19.0 24.4 21.6

46.3 46.5 34.0 26.4 26.2 21.1 28.0 21.4

BC-10 cc-8 AC-4 AC-10 AC-27 AC-7 AC- 5 AC-17

650 650 650 650 650 650 650 650

2 2 0.5 0.2 0.05 0.02 0.005 0.002

36,'300 42,400 32,900 36,300 32,400 34,400 33,900 33,600

88,500 85,200 81,500 78,200 68,400 65,200 68,400 66,700

AC-28 AC-16

700 700

0.05 0.00

39,500 32,400

68,400 63,100

18.8 20.0

19.8 29.3

25.8 23.5

14.9 21.7

760 760 760 760 760 760 760

2 0.5 0.2 0.05 0.02 0.005 0.002

41,600 30,800 32,100 29,900 32,400 32,700 32,600

76,600 72,700 71,900 64,500 63,800 54,500 47,200

36.8 37.1 33.3 25.1 20.0 12'7 9.4

40.8 40.2 38.9 41.6 43.8 39.2 39.5

24.4 30.7 21.9 35.0 42.4 41.0 42.7

28.0 36.9 24.7 43.1 55.3 52.9 56.0

CC-15 CC-14

850 850

2 0.5

33,200 28,900

66,300 60,600

30.0 23.2

48.0 49.2

46.3 43.9

62.5 58.2

cc-12 AC-6 cc-11 cc-10 AC-15

850 850 850 850 850

0.2 0.05 0.02 0.005 0.002

29,600 28,300 30,000 29,200 26,400

54,100 43,400

16.3 11.2 7.8 2.0 1.5

51.4 53.2 43.6 44.4 45.0

50.8 49.8 48.7 50.9 43.9

71.1 69.0 67.0 71.6 58.3

cc-2 cc-9 cc-5 AC-12 cc-4 cc-3 AC-14

40,400

30,600 26,400

51.5

44.4 37.1 28.5 23.8 16.8 22.6 22.8

I-J

Fig. 4. Tensile Ductilities of MSRE Surveillance Control Specimens, Heat 5081.

. , I

1 1 1 1 1

I 1 1 1 1

Fig. 5. Influence of Strain Rate on the Ductility of MSRE Surveillance Control Specimens, Heat 5081.

Table 3.

Specimen Number

Test Temperature

D-16 D-19

Results of T e n s i l e T e s t s on MSRE S u r v e i l l a n c e Specimens Heat 5081 Strain Rate (min-l)

Stress ( p s i ) Pield Ultimate

25 25

0.05 0.05

51,lQO 54,100

105,500 109,000

D-15

200

0.05

42,700

F-2 F-1 E-15 F-7 D- 24 F-23 F-10 F-19

400

("a

Elongation ($) Uniform Total

Reduction i n Area ( $1

38.5 42.6

38.7 42.6.

31.3 25.9

99,600

49.0

49.4

33.3

51.6 33.9 49.1

34.4

400

91,400 88,300 93,800 92,200 94,100 91,700 93,300 92,500

49.2

0.5. 0.2 0.05 0.02 0.005 0.002

41,200 43,700 39,900 38,300 37,100 37,800 38,80G 39,100

F-5

450

0.002

38,200

86,900

F-8 F-20 E-6 D- 9 E-25 E- 12 F-13 E-9

500 500 500 . 500 500 500 500 500

2 0.5 0.2 0.05 0.02 0.005 0.002 0,002

44,000 36,400 37,300 38,600 36,600 3 8,000 38,800 38,000

85,600 87,000 86,500 90,200 83,600 76,800 75,800 84,800

D-25 F-27

550 550

0.05 0.002

35,400 42,200

E- 23 E-24

600 600

0.05 0.002

35,200 36,100

400 400 400 400 400 400

T r u e Fracture Strain

(46)

37.0 30.0

40.7

33.3

47.1

50.9 46.1 50.4 47.7

32.3

42.0 39.5 41.5 46.9 40.7 44.7 47.7 38.9

37.8

38.6

25.8

30.1

44.4

22.4 31.0

46.0 44.1 48.5 51.0 37.5 24.1 23.1 32.1

31.6 36.2 32.1 31.9 30.2 24.2 21.9 29.8

77,800 62,700

31.6 11.8

32.1 13.8

26.1 3.34

30.3 6.5

74,800 62,100

25.6 15.0

26.4 15.8

31.8 16.7

38.2 18.3

33.2

48.3 49.4 49.3 45.8 49.9

43.1 47.8 50.6 37.0 23.3

51.0

32.5

33.9 37.2 36.0 37.7

38.2 45.2 38.7 38.7 35.8 27.8 24.9 35.4

...

. ..

_ *.

. ..

.-..~

~". , . ., ., ~. _.,."" ,...

"^_

.. . ...

. .,

, ,,..

...

. .

Table 3 (continued)

Specimen Number

Test Temperature ( "C)

Strain Rate (min-1)

Stress ( p s i ) Yield Ultimate

Elongation (&> Uniform Total

Reduction in Area

True Fracture Strain

($1

21.8 15.4 2.9 22.5 13.9 17.6 14.6 11,6

24.4 16.9 21.5 58.4 25.4 14.8 19.1 15.9 12.2

F-18 F-6 F-26 F -3 E-3 E-7 E-13 E-19 E- 14

650 650 650 650 650 650 650 650 650

2 0.5 0.5 0.5 0.2 0.05 0.02 0.005 0.002

36,700 33,400 30,500 34,300 37;200 34,600 33,800 34,600 34,400

61,100 63,900 34,900 75,600 64,200 57,200 53,600 53,000 48,400

20.8 18.2 2.6 34.0 14.9 13.8 11.1 10.8 8.2

24.0 18.9 3.7 35.3 15.8 14.3 12.9 11.3 9.0

E- 22 E-2

700 700

0.05 0.002

31,700 33,800

53,900 44,000

13.8 4.8

14.2 5.5

12.9 6.7

13.9 6.9

F-22 D-8 D-13 E- 8 D-10 D-27 E-20

760 760 760 760 760 760 760

2 0.5 0.2 0.05 0.02 0.005 0.002

36,100 31,000 31,300 31,400 32,000 36,500 32,100

57,600 49,100 49,400 43,200 42,200 40,600 36,700

18.8 12.0 11.9 6.7 5.2 4.0 1.9

22.0

14.7 11.0 10.2 6.2

3.3

15.9 $11.5 10.5 6.1 4.6 2.6 3.6

E-4 E-27 Ell F-17 D- 14 D-23 E-21

850 850 850 850 850 850 850

2 0.5 092 0.05 0.02 0.005 0,002

32,700 33,600 30,700 30,600 20,200 21,800

39,100 38,600 32,400 30,700 20,200 21,800

8.7 5.4 1.6 2.3 1.7 0.3 0.7

9.0 5.5 0.8 2.4 0.9 0.2 0.3

4.4 3.5 3.0 1.8 1.2

0.7 0.7

12.9

12.4 7.4 5.7 4.3 3.9 8.4 4.6

3.8 2.3 2.0 2.0 2.1

29.1

4.6 2.6

. . ,

15 ORNL-OW 67-244

I E = .os MIN-I

& .002

MIN-I

TEST TEMP. *C

Fig. 7. Influence of Strain Rate on the Ductility of Hastelloy N (Heat 5081) MSRE Surveillance Specimens.

16 4.2

4.0

+ 0

YELD STRESS

A ULTIMATE

STRESS

m TOTAL ELONGATION min-’

C 0

400

200

300

400

500

700

600

800

900

to00

TEST TEMPERATURE PC)

Fig. 8 .

Comparative Tensile Properties of I r r a d i a t e d and Unirradiated

M5FE Surveillance Specimens, Heat 5081. The y i e l d stress is unaffected by i r r a d i a t i o n .

The ultimate s t r e s s i s

reduced approximately 846 up t o about 600°C where t h e reduction becomes greater w i t h increasing temperature. The t o t a l elongation a t f r a c t u r e f o r t h e i r r a d i a t e d m t e r i a l i s lower by about 3O$ a t room temperature, but recovers t o be almost equivalent a t 400°C.

A s t h e temperature i s increased above 400”C, t h e d u c t i l i t y of t h e

irrailiated material drops t o where it i s only about 4%of t h a t of t h e

unirradiated specimens.

The s t r a i n r a t e versus temperature data a r e 11

t r e a t e d i n a similar way i n Fig. 9. A t 400°C t h e surveillance and control specimens have about t h e same d u c t i l i t y with only a s l i g h t decrease i n t h e r a t i o with decreasing s t r a i n r a t e .

A t 500°C there i s a sharp drop i n t h e

r a t i o a t a s t r a i n r a t e of about 0.05 min”.

This sharp change i n s t r a i n

r a t e s e n s i t i v i t y i s probably’due t o the t r a n s i t i o n from transgranular t o intergranular fracture.

!be r a t i o i s a b i t confusing a t 650°C; i t s r i s e

with decreasing s t r a i n r a t e i s due t o the f a c t t h a t t h e d u c t i l i t y of t h e control specimens decreases more rapidly with decreasing s t r a i n r a t e than that of t h e surveillance specimens.

A t 760 and 850°C the r a t i o becomes

quite small and i t s dependence on s t r a i n r a t e becomes l e s s .

8 5 0 0 OC

.I STRAIN RATE, MIN.-~

.01

V0SO0C

Fig. 9. Comparative p u c t i l i t i e s of MSRE Surveillance Specimens as a Function of S t r a i n Rate, Heat 5081. The r e s u l t s of t h e t e n s i l e t e s t s on the control specimens of heat 5085 a r e given i n Table 4. The t o t a l elongation a t f r a c t u r e i s p l o t t e d i n Fig. 10 as a function of t h e test temperature.

The c h a r a c t e r i s t i c d u c t i l i t y minimum i s obtained, but t h e temperature of t h e minimum d u c t i l i t y does not appear t o be sensitive t o s t r a i n r a t e . The r e s u l t s of t h e t e n s i l e t e s t s on t h e surveillance specimens from

heat 5085 a r e given i n Table 5.

The fracture elongation i s p l o t t e d a s a

function of t e s t temperature i n Fig. 11. The d u c t i l i t y drops precipitously above 500째C w i t h t h e elongation being lower a t t h e lower s t r a i n r a t e . The r a t i o of t h e i r r a d i a t e d property t o t h a t of t h e unirradiated property f o r heat 508 The y i e l d and ultimat

shown i n Fig. 12 as a function of temperature.

resses of t h i s heat a r e influenced about the same

by i r r a d i a t i o n as those pf heat 5081 (Fig. 8 ) .

The elongation a t low temperatures i s not reduced a s much by irradiation, but it does not recover as the

t e s t temperature i s increased.

. -

. ._,..._._I

.......

.. .."... .

." ....

. .. ,

. . .~ . .

Table 4, Results of Tensile Tests on MSRE Surveillance Control Specimens Heat 5085

Specimen Number

Test Temperature

("a

DC-24

FC-3 E-20

DC-23 DC-19 Dc-26 E-18 DC-13 FC-2

DC-17 E-16 DC-14

Dc-25 Dc-5 Dc-10 Dc-3 DC-9 Dc-22 Dc-8

25 25

0.05 0.05

200 400

0.05

500 I

Strain R a te (min-1)

500 550 550 550 600 600 650 650 700 700 760 760 850 850 '

0.05 0.05 0.002

0.05 0.002 0.002

0.05 0.002

0.05 0.002 0.05 0.002 0.05 0.002 0.G5 0.002

Stress ( p s i ) Yield Ultimate

Elongation CQ) Total

Uniform

Reduction True Fracture i n Area Strain

(9) 46,200 45,500 39,100 34,800 33,600 33,400 33,700 32,500 33,600

109,200 111,200 105,200 95,800 94,300 91,700 89,200 74,000 77,900

40.0

32,200 32,100 31,800 31,500 29,200 30,900 28,100 28,900 25,700 27,900

78,300 69,600 70,100 62,500 64,000 62,100 60,800 51,500 45,100 28,400

33.8 26.5 25.8 22.8

28.4

29.5 28.3 33.0 35.1.

46.8 48.6 47.6 48.8 43.3 47.0

26.5 30.3

22.3 27.0 11.0 11.5 1.4

40.0 46.8 49.8 48.8

28.61 31.45 36.69 39.01 41.48 37.78 35.19 26.1

($1 33.8 39.5

33.98

46.1 49.6 54.1 47.7 43.4 30.2 41.6

34.6 27.3

32.60

37.8

25.55

26.8

29.97 27.15' 28.14 24.04 32.16 36.07 47.23 43 e 76

29.6 35.9 31.8 33.2 27.5 38.7 44.8 64.1 55.7

49.3 44.3 47.5 27.5 31.0

24.3

38.8 39.2

? !3

ORNL-DWG 67-244

o E = .002 MIN-

500

I 600

700

800

900

TEST TEMP, "C Fig. 10. Tensile Ductilities of E R E Surveillance Control Specimens, Heat 5085.

1000

..........

,. ..............

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

........

.ll.l*l."

......

. . ~.

........

..,~I..

Table 5.

Test Specimen Number

Temperature ("C)

Results of Tensile Tests on USRE Surveillance Specimens Heat 5085

Strain Rate (min-l) 2

Stress ( p s i )

Elongation ($)

Reduction i n Area

True Fracture Strain

Total

($1

25.6 26.7

28.4 27.3

17.1 19.7

19.0 22.0

100,300

34.3

34.5

26.0

30.1

Yield

Ultimate

Uniform

62,300 50,200

101,500 95,600

48,100

C-27 A-25

25 25

A-16

0,5 0.05

A-15

200

0.05

39,500

94,100

37.8

38.6

28.2

33.3

A-26

400

0.05

35,700

$7,300

35.0

36.0

26.3

30.6

A-9 B-23

500 500

0.05 0.002

34,900 34,000

8'7,900 71,600

42.2 21.9

42.8 23.1

33.9 27.9

40.0 32.6

B-1 B-5

550 550

0.05 0.002

42,000 33,700

74,000 55,100

19.6 10.4

20,o 12.7

18.7 14.7

20.9 15.9

B-26 B-4

600 600

0.05 0.002

32,500 32,300

62,000 52,000

18.2. 11.1

19.6

21.7 12.5

24.5

12.0

B-19 '8-6

650 650

0.05 0,002

32,000 32,100

52,800 42,900

12.6 6.5

13.7 9.4

13.9 7.9

c-20'

c-1

700 700

0.05 0.002

29,900 37,800

43,600 43,100

9.3 2.4

12.3 2.8

5.6 5.9

B-2 c-21

760 760

0.05 0.002

28,900 28,010

41,100 33,700

8.0 2.4

8.5 3.5

10.0 2.3

B-20

850 850

0.05 0.002

27,900 20,600

31,400 20,600

2.5 0.8

3.8

C-8

, I

1.8

0.65 1.3,

13.5 15.0 8.1 9.4 5.9 10.5 2.0 0.20 0.60

......

.l..*l...-..l*.*..

.,,

c i

Fig. 11. Tensile Ductilities of MSRE Surveillance Specimens, Heat 5085.

4 .O

57- 2455

-A-

>. >.t t a = w

g 0.8 $n E f

-t--

O O W Wt-

2 Q6

2s 3

0.4

0.2

cd c

100

200

300

400

500

600

700

800

900

TEST TEMPERATURE ("CI

Fig. 12. Comparative Tensile Properties of Irradiated and Unirradiated MSRE Surveillance Specimens, Heat 5085.

4000

22 The elongations a t f a i l u r e f o r the two heats of material are compared i n Figs. 13 and 14.

A t a s t r a i n r a t e of 0.05 min'l

(Fig. 13) there are

several minor variations i n the d u c t i l i t i e s of the control specimens.

The

main difference i s t h a t the d u c t i l i t y of heat 5085 i s consistently lower up t o about 500째C.

Both heats of the surveillance specimens exhibit a

reduction i n d u c t i l i t y at a test temperature of 25째C; however, the reduction is greater f o r heat 5085.

The d u c t i l i t y of heat 5081 re'covers

some with increasing test temperature, but heat 5085 maintains i t s reduced ductility.

Above about 500째C the d u c t i l i t y of t h e controls drops rapidly,

but t h e d u c t i l i t y of t h e irradiated surveillance specimens decreases more Both heats have very s i m i l a r d u c t i l i t i e s a t temperatures above

rapidly. 600째C.

The d u c t i l i t i e s of t h e two heats at a s t r a i n r a t e of 0.002 min-'

are compared i n Fig. U. The control specimens of both heats exhibited very similar d u c t i l i t i e s , the characteristic d u c t i l i t y minimum being exhibited.

The irradiated surveillance specimens have much lower

d u c t i l i t i e s , but the values are very similar f o r t h e two heats.

TEST TEMP.

Fig. 13. Comparative Tensile Ductilities of IERE Surveillance Specimens and Their Controls a t a S t r a i n Rate of 0.05 min'l.

23 60

-8z 40 0 5 z 30 sw 20 2

io P

0 0

100

200

400

300

500

600

700

800

I000

900

TEST TEMPERATURE ("C)

Fig. 14. Comparative Tensile D u c t i l i t i e s of M3RE Surveillance Specimens and Their Controls at a S t r a i n Rate of 0.002 min-l. W e took a b r i e f look a t how t h e t e n s i l e properties of t h e material

varied as a function of heat treatment i n t h e unirradiated s t a t e .

The

properties of heat 5081 i n several metallurgical conditions are given i n Table 6.

The anneal f o r 2 h r a t 900°C generally decreased the strength

and increased t h e rupture s t r a i n over t h a t of t h e as-received material. One exception t o t h i s behavior i s an increase i n ultimate stress a t 650°C The exposure t o molten salt a t 650°C

due t o t h e 2 h r anneal a t 900°C.

f o r 4800 h r caused a decrease i n t h e d u c t i l i t y and s l i g h t variations i n t h e strength.

The t e n s i l e properties of heat 5085 i n t h e unirradiated The properties of t h i s heat are not

condition are given i n Table 7. significantly different i n t

2 h r a t 900°C.

The exposure

as-received condition and after annealing molten salt a t 650°C caused a general

decrease of 10 t o 20% i n t h e rupture d u c t i l i t y , but t h e strength was not affected significantly. The p o s t i r r a d i a t i o n t

i l e properties of several heats of MSRE

material are compared i n Table 8.

The first two sets of data f o r

heat 5065 show t h a t t h e p o s t i r r a d i a t i o n properties w e r e not affected by

. . . . . . . .

..i_ .".I_,~

i_i

....

. . . . . -.

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

......

Table 6, Tensile Properties of Unirradiated Hastellay N Heat 5081 Specimen Number

5006 5005 5004 5008 5007

Test Temperature

("a

25 500 500 650 650

4300 4303

500

4301 4302

650 650

AC- 8 AC- 19 BC-9

AC-27 AC- 17

25 500 500 650 650

Strain Rat e (min-l)

Reduction in Area

($1 As-received 77,400 130,600 38,200 103,300 40,000 103,200 39,100 73,400 38,200 65,100

0.05 0.05 0.002 0.05 0.002

Elongation ($) Dnlrorm Tot a1

Stress (psi) U L t imate Yield

Annealed 2 hr at 900째C 0.05 52,600 125,300 0.05 32,000 100,300 0.05 32,200 81,800 0.002 32,900 74,900 r

Annealed 2 hr at 900째C plus 4800 hr in MSRE I 0.05 47,700 118,700 0.05 35,800 97,800 0.002 36,200 95,300 0.05 32,400 68,400 0.002 33,600 66,700

44.9 53.3

46.9

51.2 18.0 14.4

19.8 15.2

59.5

56.7 57.8 31.7 29.0

50.5 44.4 29.9 31.8

60.7 33.9

29.5

salt at 650째C 55.9 57.6 53.6 56.6 46.2 47.0 23.8 24.6

22.8

48.0 34.0 41.5 19.1 15.8

55.3 52.6

23.2

48.8 46.2 38.1 23.1 '21.6

3 '

Table 7. Tensile Properties of Unirradiated Hastelloy N Heat 5085

Specimen Number

Test Temperature ( "C>

Strain Rate (min-l)

Stress (psi) Yield Ultimate

Elongation ( 8 ) Uniform Tota1

Reduction in Area

($1 As-received

25 427 60 65 650 650. 760

76 77 2 84 78 2 85 2 83 79 80 81

982

0.05 0.05 0.02 0.05 0.02 0.002 0.05 0.05 0.05

25 500 500 650

0.05 0.05 0.002 0.05

871

4295 4298 4299 4296

52,200 116,400 30,700 102,900 32,200 85,100 28,700 80,700 31,900 65,000 64,300 30,500 32,100 61,500 30,700 42,300 23,100 23,100 Annealed 2 hr at 900째C

51,500 32,600 33,500 29,600

120,800 94,800 100,200 75,800

51.3 57.6 46.6 35.5 25.8 22.6 24.7 9.0 1.8

52.5 59.4 47.6 36.7 31.8 24.1 27.0 31.8 40.2

56.3 49.9 40.4 33.2 27.2 28.8 31.9 33.4 43.9

52.3 51.2 52.0 31.7

53.1 54.1 53.3 33.7

42.2 40.9 41.7 34.6

Annealed 2 hr at 900째C plus 4800 hr in MSRE salt at 650째C FC-3 E19 DC-26 E-14 E-25

25 500 500 650 650

0.05 0.05 0.002 0.05 0.002

45,500 33,600 33,400 31,800 31,500

111,200 94$300 91,700 70,100 62,500

46.8 48.8 43.3 25.8 22.8

46.8 49.3 44.3 26.8 24.3

31.5 41.5, 37.8 30.0 27.2

.- .-- -.-...~... "

Table 8. Specimen Number

Heat Mber

-..

^ "

P o s t i r r a d i a t i o n Tensile Propertiesa of Several Heats of NSRE Hastelloy N

Boron Level

(m)

Irradiation Temperature ( 'C)

Thermal Dose (neutrons/cm2)

Teat Temperature ( 'C)

Strain Rate (min-1)

Streas ( p s i ) eld U l t lmate

gtaadtL

Reduction i n Area ( %)

x 1020 57@

2289'

5065 5065 5065 5065 5065 5065 5065 5065 5065 5065 5065 5065

20 20 20 20 20 20 20 20 20 20 20 20

43 43 43 43 43 43 43 43 43 43 43 43

8.5 8.5

5067 5067 5067

20 20 20 38 38 38 20 20 20

500-700 500400

1.4 1.4 1.4 1.4 1.4 1.4 1.4 1.4 1.4

5085 5085 5085

5065 5065 5065

8.5 8.5

Experiment ORR-149 25 200 650 650

871

0.05

8.5 8.5

871

0.002

25 200 650

0.05

650 871 .87l

0.002 0.05

8.5 8.5

500-700

0.05 0.05 0.002

8.5 8.5 8.5 8.5

500400 500400 500-700 500400 500400 5woo

0.05

0.05 0.05

0.002

Experiment ORR-155 25 650 650 25 650 650 25 650 650

0.05 0.05 0.002 0.05 0.05 0.002 0.05 0.05 0.W

31.5 36.1 26.3 12.2 1.7 0.9 30.0 37.3 25.3 __ .~ 13.7 1.7 0.8

35.5 39.2 27.3 13.1 1.8 1.8 33.6 39.8 25.8 ~. . 14.3 1.9 1.6

59,000 123,700 38,400 66,800 36,400 59 900 46,300 110:600 30,800 64,400 30,200 51,800 50,100 ll7,OOO 37,400 62,100 34,800 49,100

49.4 14.0 9.6 41.1 18.0 9.3 54.4 12.3 6.4

51.2 14.0 9.6 41.2 21.2 9.9 56.1 12.4 6.5

45.4 20.5 16.0 40.3 19.1 u.4 53.2 17.2 15.3

49,100 42,200 41,200 42,600 41,900

68,600 56,300 59,000 51,800

9.4

46,OOO

9.1 8.2 10.8 5.9 2.8

11.3 6.1 2.8

14-7 11.7 14.7 10.2 5.6

46,700 37,700 40,000

76,200 53,300 57,500

21.6 9.3 11.4

22.2 10.0 ll.6

28.8 10.1 17.5

511100 105,500 34,600 57,200 34,400 48,400 48,100 100,300 32,000 52,800 32,100 42,900

38.5 13.8 8.2 34.3

38.7

31.3 13.9 11.6 26.0 13.9 7.9

102,900 l35,100 44,600 82,300 ll9,600 76,900 40,800 57,400 33,m

36,400

23,200 23,400 101,500 132,200 78,ll8,300 35,100 77,700 38,100 66,200 37,100 38,500 25,900 25,900

52.0 54.8 24.5 , 21.9 3.25 6.07 55.2 45.9 22.6 17.3 2.94 5.26

Experiment Ern(-41-31 1273' 1276' 1270b 127g' 1274

5065 5065

383' 380b 384i-J

5065 5065

&la' E-7 E-14' A-16'

5081

5c65

5065 5065

5065

20 20 20 20 20

600 600 600 600 600

f 100

20 20 20

4.50

4.50 c150

f 100

f 100 f 100 f

100

3.5 3.5 3.5 3.5 3.5

550 600

0.002 0.002

650 650. 760

0.05

0.002 0.002

Experiment Ern(-41-30 650 650 650

0.05

0.002 0.002

8.5

Experiment USRE

E-$ B-6

5081 5081 5085 5085 5085

50 50

50 38 38 38

650 650 650 650 650 650

1.3 1.3 1.3 1.3 1.3 1.3

a h a d t a t a d in a helium environment except for apeciuens from bAa received.

650 650 25 650 650

DBRE.

0.05 0.05 0.002 0.05

0.05 0.002

'Annealed 8 hr a t 871%. dAnnenled 2 hr at 900%

12.6

6.5

14.3 9.0 34.5 13.7 9.4

,tis whether t h e , m a t e r i a l was i r r a d i a t e d i n t h e as-received condition o r whether it w a s annealed 8 h r a t 871°C. These specimens were irradiated a t

43"C, and t h e d u c t i l i t i e s a t 25°C (0.05 min'') 34 t o 36 and I 3 t o 14$, respectively.

and 650°C (0.002 min-l) were

When i r r a d i a t e d a t an elevated

temperature, t h i s same heat had elongations a t 650°C (0.002 min'l)

6.5 and 6.1%. Heats 5067 and 5085'showed somewhat b e t t e r d u c t i l i t i e s a t 650°C (0.002 min-l) with values of 9 t o 10% being obtained f o r i r r a d i a t i o n s a t elevated temperatures.

The d u c t i l i t i e s of t h e two surveillance heats

a t 650°C agree closely with those observed previously f o r heats 5085 i

and 5067. However, t h e room temperature d u c t i l i t i e s a r e lower than those observed f o r any heat of material i r r a d i a t e d a t an elevated temperature.

Heat 5081 was included i n another experiment i n t h e Oak Ridge Research Reactor,6 and the r e s u l t s are compared with those f o r the MSRE surveillance specimens i n Fig. 15.

These r e s u l t s indicate t h a t t h e properties of the

material are unaffected by the s a l t environment.

6w. R. Martin and J. R. Weir, "Effect of Elevated Temperature I r r a d i a t i o n on t h e Strength and Ductility of t h e Nickel-Base Alloy, Hastelloy N," Nucl. Appl. 1(2), 160-67 (1965). 1c

--z

ORNL-DWG 67-353t

1.a

r=0.002 m i d

E9 0.8 5 W -I

THIS STUDY, 4,,=1.3 x1020nvt,

ORNL-TM-1005. +,h=9Xi020nv T=7000C

0.6

400

500

600 700 800 TEST TEMPERATURE CC)

900

4000

Fig. 15. Comparative Effects of I r r a d i a t i o n i n E R E and ORR on t h e Ductility of Hastelloy N, Heat 5081.

W *

We a l s o ran several creep-rupture t e s t s on the i r r a d i a t e d materials t o evaluate t h e i r properties under creep conditions. For comparison, t h e results of several creep-rupture t e s t s on unirradiated heat 5081 are given i n Table 9.

O f t h e two heat treatments investigated, 2 hr a t 900°C and

the st&eillance

control treatment, the l a t t e r resulted i n slightly lower

rupture strains.

The creep-rupture data are plotted i n Fig. 16, and the

IERE surveillance control specimens exhibit a s l i g h t l y reduced rupture

However, the minimum creep r a t e i s the same a f t e r the two heat

life.

treatments (Fig. 17). *

Table 9.

Creep-Rupture Properties of Unirradiated Hastellay N a t 650°C Heat 5081 ~~

Test Nuniber

Stress (Psi 1

Rupture Life

Rupture Strain

Reduction i n Area

($1

Minimum Creep Rat e

(%/W

Annealed 2 hr a t 900°C 6159

70,000

5.1

35.0

12.8

2.1

6155

55,000

71.8

33.9

29.2

0.26

6156

47,000

76.0

12.4

27.0

6157

40,000

648.3

42.5

25.2

0.091 0.032

6158

32,400

2133.3

46.8

20.1

0.012

6160a

27,000

2349.0

10.2

3.7

O.oOLc7

Annealed 2 hr a t 900°C plus 4800 h r a t 650°C i n MSRE s a l t 6077

55,000

40.7

24.3

21.9

0.25

6075

47,000

147.9

27.2

21.9

0.098

6076 6071

40,000 32,400

321.0 848.0

31.1

26.7 16.1

0.061 0. ol4

16.5

%iscontinued p r i o r t o f a i l u r e .

ORNL-DWG 67-7934

PRETEST ANNEAL A 2 hr AT 9OO0C MSRE CONTROLS

2 40 v)

E v)

io 0

roo

40'

io2 RUPTURE LIFE (hr)

Fig. 16.

Creep-Rupture Properties of Hastelloy N a t 650째C, Heat 5081.

ORNL-DWG 67-7935

E ' in 20

IO-^

lo-2

40째 MINIMUM CREEP RATE (%/hr)

Fig. 17.

Minimum Creep Rate of Hastelloy N a t 650째C, Heat 5081.

L) The creep-rupture properties of heat 5085 were investigated i n three conditions

- as-received,

annealed 2 h r a t '900"C, and 2 hr a t 900°C plus The rupture s t r a i n of the as-received

4800 hr i n molten s a l t (Table 10).

material i s improved by annealing at 90O0C, but the long aging treatment a t 650°C brings about a slight reduction i n the f r a c t u r e d u c t i l i t y . Figure 18 compares the rupture l i f e a f t e r the various heat treatments. The pattern i s the same as t h a t f o r t h e d u c t i l i t y with t h e m i n i m strength being observed f o r the as-received material and the maximum f o r t h e material However, the minimum creep r a t e was unaffected by

annealed 2 hr a t 900°C. heat treatment (Fig. 19).

Table 10.

Creep-Rupture Properties of Unirradiated Hastellay N a t 650°C Heat 5085

Test Muuiber

Stress (Psi 1

Rupture Ef e

Rupture Strain

Reduction i n Area

($1

(hr)

H n i m Creep Rate

(4)

(Vhr)

21.9 13.3 14.6 5.6 5.6 6.4 7.1

9.0 0.27 0.086 0.024 0.024 0.006 0.006

As-recezved 70, OOO 55, OOO 47, OOO 40, OOO 40,000 30, OOO 30, OOO

3792 3710 3781 3713 37l4 3975 3795

0.4 10.8 48.6 179.5 215.7 672.6 1030.0

28.0 10.9 12.5 10.9 2.4.0

6.3

9.4

Annealed 2 hr a t 900OC 6153 6l49 6150 6151 6152a 6154

70,000 55, OOO 47,000 40, OOO 32,400 27,000

4.1 49.5 246.8 725.1 2386.0 2445.0

32.6 22.6 38.5 37.6 37.7 9.0

30.7 30.8 28.9 18.4 19.9 4.0

2.1 0.26 0.084 0.029 0,009 0.0035

Annealed 2 hr a t 900°C plus 4800 hr a t 650°C i n E R E s a l t 6074 6073 6072 6070

55,000 47,000 40,000 32,400

20.5 124.6 513.3 2054.6

20.8 31.2 22.3 26.7

21.9 22.9 19.7 16.7

0.30 0.080 0.029 0.0082

%iscontinued p r i o r t o Tailme.

31 ORNL-DWG 67-7936

io 0 40-'

to' 1 8 RUPTURE TIME (hr)

Fig. 18. Creep-Rupture Properties of Hastelloy N a t 65OoC, Heat 5085.

I ORNL- DWG 67-7937

i t

io+

IO-'

100

10'

MINIMUM CREEP RATE (%/hr)

Fig. 19. Minimum Creep Rate of Hastelloy N a t 650째C, Heat 5085.

32 The r e s u l t s of t h e t e s t s on the surveillance specimens are given

i n Table ll. The properties ( d u c t i l i t y and strength) of heat 5081 a r e superior t o those of heat 5085.

However, a comparison of these data w i t h

those f o r the control specimens i n Tables 9 and 10 shows t h a t i r r a d i a t i o n has significantly reduced the rupture l i f e and d u c t i l i t y of both heats. The rupture l i v e s are compared i n Fig. 20 f o r both heats of material i n the irradiated and unirradiated conditions. greater as the s t r e s s l e v e l increases.

The effect of i r r a d i a t i o n i s

The minimum creep r a t e s of the

two heats of material i n the i r r a d i a t e d and unirradiated conditions are compared i n Fig. 21.

This parameter appears t o be independent of the

variables being studied with the possible exception of the i r r a d i a t e d specimens exhibiting a higher s t r a i n r a t e a t t h e 47,000-psi s t r e s s level. Table 11. Postirradiation Creep-Rugture Properties of b5Rl3 Surveillance Specimens a t 650째C

Rupture I;ife

Rupture Strain

Reduction i n Area

M h i m u n Creep

Test Nunher

Heat Number

Stress (psi)

R-230

5085

47,000

0.8

1.45

10.0

0.81

R-266

5085

40,000

24.2

1.57

9.7

0.031

5085

32,400

148.2

1.05

6.5

0.006

R-250

5085

27,000

25.2

1.86

2.2

0. ow

R-229

5081

47,000

8.7

2.28

9.2

0.20

R-231

5081

40,000

. 98.7

.2.65

5.8

0.017

R-226

5081

32,400

474.0

3.78

4.0

0.0059

R-233

5081

27,000

2137.1

4.25

0.58

0.0009

R-267

(hr)

(4)

a Annealed 2 h r a t 9oO째C p r i o r t o irradiation.

33 ORNL-DWG 67-7938

fn v)

Iv)

0 IO+

roo

IO‘

io2

io3

io4

RUPTURE TIME ( h r )

Fig. 20. Comparative Creep-Rupture Properties of Surveillance and Control Specimens a t 650°C.

34 The results of the creep-rupture tests on t h e surveillance specimens

were compfured with data which we had obtained on t h e

"MSmmaterials"

other i r r a d i a t i o n experiments i n the Om. The results used i n t h i s comparison are given i n Table 12. Fig. 22.

The creep-rupture l i v e s a r e compared i n ,

The data f o r heat 5085 agree quite w e l l w i t h those obtained

previously i n t h e ORR f o r t h i s same heat and several other =E However, the results f o r heat 5981 are slightly superior.

heats.

The f r a c t u r e

s t r a i n s f o r the various heats of i r r a d i a t e d material a r e compared i n Fig. 23. The data indicate a minimum d u c t i l i t y f o r a rupture l i f e of 1t o 10 h r with

d u c t i l i t y increasing with increasing rupture l i f e . heat 5085 a f t e r i r r a d i a t i o n i n t h e

MSm i s

A lower d u c t i l i t y of f

a l s o indicated, although t h e

data s c a t t e r will not permit t h i s as an unequivocal conclusion.

The

superior d u c t i l i t y of heat 5081 and t h e l e a s t d u c t i l i t y of heat 5065 (heat used f o r the top and bottom heads of MSRE) are c l e a r l y i l l u s t r a t e d . Since t r a n s i e n t s may occur i n which t h e material i s s t r a i n e d a t some temperature other than t h e operating temperature (650°C), we ran a series of t e s t s t o determine what e f f e c t such t r a n s i e n t s could have on the f r a c t u r e s t r a i n at 650°C.

The r e s u l t s of these tests a r e given i n Table 13.

The specimens w e r e strained a t other temperatures and then quickly cooled or heated t o 65OOC and t e s t e d t o failure.

Even though .the prestraining

treatments carried t h e specimens as far as 37% of t h e s t r a i n t o f a i l u r e , the s t r a i n a t 650°C was not decreased.

I n f a c t , the prestraining a t

760 and 850°C seemed t o improve t h e a b i l i t y of the material t o s t r a i n a t 650 "C

. Several of the specimens w e r e examined metallographically a f t e r

testing.

Figure 24 shows the microstructure of a control specimen from

heat 5 0 8 1 t h a t was t e s t e d a t 25°C.

The specimen has undergone extensive

'deformation, and the f r a c t u r e i s t y p i c a l of a transgranular shear-type failure.

There i s no evidence of intergranular cracking.

I n contrast,

the i r r a d i a t e d specimen f r o m t h e same heat, shown i n Fig. 25, failed

intergranularly with less s t r a i n and considerable intergranular cracking. A t 650°C t h e f a i l u r e of t h e control specimen was predominantly

intergranular (Fig. 26).

The failure of t h e surveillance specimen was

a l s o intergranular a t 650°C with no microstructural evidence of p l a s t i c deformation (Fig. 27)

Table 12, Postirradiation Creep-Rupture Properties of Irradiateda Hastelloy N at 650째C

Test Number

Thermal Dose ( neutrons/ cm2)

Experiment Number

Stress (Psi)

Rupture Life (

Rupture Strain

2.8 -62.6 765.8 1907.8 28.6 13.0 17.7 117.0 135.7

0.59 2.23 1.75 2.28 0.98 0.60 0.66 1.45

0.0019 0 0010 0.028 0.018 0.016 0.0049 0.0083

361.4

2;78

0.0056

6.7 49.3 102.8 2625.8 247.6

1.90 1.61 2.88 3.70 1.48

0.25 0.0098 0.0023 0.0009 0.0055

Minimum Creep

(4)

1020

Heat 5065

R-15 R-13 R-35 R-12 R-159 . R-167 - R-65 R-168 R-215

3.0 3.0 3.0 3 .o 5.2 5.2 5.2 5.2 1.4

om-138 ORR-138 ORR-138 OM-138 ORR-148 ORR-148 ORR-148 ORR-148 ORR-155

39,800 32,400 27,000 21,500 40,000 40,000 35,000 30,000 32,400

0.46

0.086 0.011

Heat 5067

R-214

ORR-155

1.4

32,400 Heat 5085,

R-14 R-11 R-41 R-10 R-206

2.0 2.0 2.0 2.0 1.4

y r r a d i a t i o n environment:

ORR-140 ORR-140 ORR-140 Om-140 ORR-155

39,800 32,400 27,000 21,500 32,400

He-1 vol $ 0 2 .

All specimens i n t h e as-received condition.

......

~ . . . ..

....

il,

...

. . .. "_

.-fl g

. . ..

4 4

1 4

I I

- 7

"_"_

I I

....

I I

A 0

rl d

a, c,

~.~ . . " ". . . . .

.- .

Table 13.

Specimen

Number '

H f e c t s of P r e s t r a i rling on theaTensile Properties of Hastelloy N Heat 5081

Pretreatment'

Stress (psi) Yield ultimate

Elongationb ($) h i f o r m Total

None

!kue Strain

($1

34,600

53,000

10.8

11.3

14.6

15.9

E- 14

34,400

48,400

8.2

9.0

11.6

12.2

F-11

Strained !$ at 4 0 " ~ 45,900

54,700

8.0

10.0

8.2

F-25

Strained 5$ at 500°C

47,700

58,300

10.9

11.5

14.2

15.4

F-24

Strafned 5$ a t 600°C

47,900

58,500

10.4

11.3

11.0

11.,3

D-11

Strained 2$ at 700°C

40,200

54,000

9.7

10.6

14.2

15.4

F-4

Strained l$ at 760°C

35,500

56,400

11.9

12.6

15.5

16.9

F-16

Strained 0.s a t 850°C

35,700

59,800

15.2

15.9

13.5

14.7

E-19

Reduction i n Area

Fraction of' Rupture Strain a t Prestrainin Temperature

a Ruptured a t 650°C: S t r a i n rate = 0.002 min'l. bPrestraining carried out a t a s t r a i n r a t e of 0.002 min-1. C

Inciudes only the s t r a i n a t 650°C.

32 ,

38 I

Fig. 24. Photomicrographs of Control Specimen AC-8 from Heat 5081 (a) Fracture. (b) Edge Tested a t 25"C,and a t a S t r a i n Rate of 0.05 min'l. of specimen about l/4 in. from fracture. Etchant: glyceria regia.

b;! c

Fig. 25. Photomicrographs- of Surveillance Specimen D-16 from Heat 5081 Tested a t 25Â°C and a t a S t r a i n R a t e of 0.05 minâ&#x20AC;&#x2122;l. (a) Fracture. (b) Edge of specimen about 1/4 in. from fracture. Etchant: glyceria regia.

41 The f a i l u r e of t h e control material f r ~ mheat 5085 was found t o be

However, t h e elongated grains

predominantly intergranular (Fig. 28).

a t t e s t t o the large amount of s t r a i n t h a t has occurred. p r e c i p i t a t e s have been i d e n t i f i e d as M&,

The large

and they normally f r a c t u r e when

strained a t temperatures less than about 500°C. The surveillance specimen from heat 5085 t e s t e d a t 25°C i s shown i n Fig. 29.

The f a i l u r e i s largely

intergranular with numerous intergranular cracks i n t h e microstructure. The edge’ of t h e .specimen (Fig. 29b) i s quite clean w i t h no evidence of corrosion or material deposition.

However, t h e p a r t of t h e specimen t h a t

touched t h e .graphite i n the surveillance assenibly was found t o have a c t near t h e surface varying from 1 t o 2 m i l s i n depth (Fig. 30). as not distributed uniformly around the specimen and varied i n form from a lamellar t o a rope-like intergranular product.

A t 650°C t h e

f a i l u r e of t h e control specimen was predominantly intergranular (Fig. 31). The surface reaction praduct observed i n specimens from t h e reactor where

they were i n contact with t h e graphite was a l s o noted i n t h e control specimens (Fig. 32).

Although t h e micrographs t h a t have been shown are

f o r heat 5085, the surface reaction was a l s o noted i n heat 5081. Electron microprobe examination showed that t h i s layer contained‘fgom 0.3 t o 1.5 w t ’$ C, indicating t h a t t h e r e was some t r a n s f e r of carbon from the graphite t o t h e Hastelloy N where the two materials were i n contact.

Figure 33 shows t h e f r a c t u r e of t h e surveillance specimen from heat 5085 t h a t was t e s t e d a t 650°C.

The failure is predominantly i n t e r g r a n u l a r v i t h

no metallographic evidence of p l a s t i c deformation. IWraction r e p l i c a s were made on t h e surveillance and control specimens. This technique involves depositing carbon on a polished surface of the specimen and then dissolving e l e c t r o l y t i c a l l y t h e matrix i n a solution of

lo$ HC1 i n ethanol u n t i l t h e carbon f a l l s f r e e . attacked by t h e s o l u t i o washing and drying, t h e

The p r e c i p i t a t e s are not

they a r e held by the carbon. ca ca

examined i n t h e e l

After s u i t a b l e

ron microscope.

Transmission electron micrographs can be made as w e l l as selected area d i f f r a c t i o n patterns f o r phase identification.

An extraction r e p l i c a of

a control specimen from heat 5081 i s shown i n Fig. 34. The predominant feature i s the r e l a t i v e l y large p r e c i p i t a t e s t h a t have been i d e n t i f i e d

Fig. 28. Photomicrographs of Control Specimen E - 2 4 from Heat 5085 (a) Fracture. (b) Edge Tested a t 25OC and a t a Strain Rate of 0.05 an". of specimen about 1/4 in. from fracture. Etchant: glyceria regia.

u 9

)

Fig. 29, Photomicrographs of Surveillance Specimen A-16 from Heat 5085 Tested a t 25째C and a t a Strain Rate of 0.05 min'l. (a) Fracture. (b) Edge of specimen about 1/4 in. from fracture. Etchant: glyceria regia.

Fig. 30. Cross Section of t h e Buttonhead of Surveillance Specimen A-16 from Heat 5085 Tested a t 25OC. (a) 100 X. (b) 500 X.

LIJ r

Fig. 31. Photomicrographs of Control Specimen DC-25 from Heat 5085 (a) Fracture. Tested a t 650째C and a t a S t r a i n Rate of 0.002 min-l. (b) Edge of specimen about 1/4 in. from fracture. Etchant: glyceria regia.

Fig. 32. Photomicrographs of t h e Cross Section of the 3uttonhead of Specimen E-25. ( a ) 100 X. (b) 500 X. Etchant: glyceria regia.

Fig. 33. Fracture of Surveillance Specimen 3-6 from Heat 50815 Tested a t 6150째Cand a t a S t r a i n Rate of 0.002 min-l. Etchant: glyceria regia.

Fig. 34.

Extraction Replica from Control Specimen, Heat 5081.

. 48

as MgC.

A ' r e p l i c a i s sham i n Fig. 35 f o r a surveillance specimen from

heat 5081. The large MgC p a r t i c l e s are present, but t h e r e i s a l o t of f

f i n e intergranular p r e c i p i t a t e that has a l s o been i d e n t i f i e d a s MgC. The i r r a d i a t i o n appears t o enhance t h e formation of t h e f i n e intergranular i

precipitate.

Fig. 35.

Extraction Replica From Surveillance Specimen, Heat 5081.

49 DISCUSSION OF €ESULTS Because of the large amount of data presented, we w i l l briefly recapitulate t h e most important observations. 1. The control specimens from both heats of Hastelloy N exhibited the c h a r a c t e r i s t i c d u c t i l i t y minimum i n the temperature range of 600 t o 700°C.

The d u c t i l i t y a t various temperatures was reasonably insensitive

t o s t r a i n r a t e except near 650°C where t h e d u c t i l i t y decreased with decreasing s t r a i n r a t e .

2. After i r r a d i a t i o n t h e t e n s i l e d u c t i l i t y was reduced significantly. There was an unexpected reduction i n t h e room temperature d u c t i l i t y w i t h fracture s t r a i n s i n t h e range of 35 t o 40%being observed. fractures w e r e obtained a t room temperature i n heat 5085.

Intergranular The f r a c t u r e

s t r a i n generally became lower as t h e t e s t temperature was increased and the s t r a i n r a t e decreased,

A t elevated temperatures (40W50"C) the f r a c t u r e s t r a i n s were

equivalent f o r t h e two heats of surveillance specimens and were found t o be t h e same as those observed previously i n other experiments where molten salt was not present.

4. Creep-rupture tests run on unirradiated specimens indicated t h a t the p r e t e s t anneal of 2 h r a t 900°C improved the rupture strength and d u c t i l i t y over t h a t of the material i n the as-received condition. Thus, t h e stress-relieving anneals a t 871°C used i n fabricating t h e BERE improved t h e base properties. However, t h e long exposure of t h e control specimens a t 650°C (operating temperature of t h e BERE) caused slight reductions i n rupture strength and d u c t i l i t y . 5.

The creep-rupture l i f e of t h e surveillance specimens was less

than t h a t of t h e control specimens, t h e e f f e c t being greater a t t h e higher stress levels.

Heat 5085 was

ffected much as we had observed

previously i n other experiments on t h i s same heat and other MSRE heats. Heat 5081 exhibited a sign 6.

The creep-rupture

smaller e f f e c t . f irradiated Hastelloy N goes

through a minimum value f o r a rupture l i f e of from 1 t'o 10 h r f r a c t u r e s t r a i n increases as the rupture l i f e increases (or t h e ' s t r e s s l e v e l decreases).

Heat 5081 exhibited appreciably higher fra

ins

than did heat 5085.

Heat 5065 (material used f o r the top and bottom

heads of t h e MBE) exhibited the lowest d u c t i l i t y of any heat examined t o date.

A s e r i e s of t e n s i l e t e s t s indicated t h a t prestraining at

temperatures Over the range of 400 t o 850째C did not appreciably lower the fracture s t r a i n of t h e material when t e s t e d . t o f a i l u r e a t 65OOC.

8. Neither t h e control nor t h e surveillance specimens showed any evidence of corrosion.

However, there was a surface product from

0.001 t o 0.002 in. i n depth t h a t formed where t h e Hastelloy N and graphite were i n contact.

Microprobe studies indicate t h a t t h i s layer i s high i n

carbon, and hence t h e reaction product i s probably a metal carbide. 9.

Extraction replicas indicated t h a t more intergranular precipitate

f o r m d i n the surveillance specimens than i n t h e controls. Thus, irradiation must enhance t h e nucleation and growth of t h e p r e c i p i t a t e (identified a s Q C )

The changes i n t h e unirradiated properties of these heats of

Hastellay N have been demonstrated p r e v i ~ u s l y . ~However, these changes a r e r e l a t i v e l y small, and t h e properties do not appear t o be deteriorating enough f o r concern.

They a r e probably due t o t h e solution and

reprecipitation of &C. The effects of irradiation on Hastelloy N are drastic, but p r e t t y

much a s expected.

Previous work had Shawn a reduction i n the rupture

d u c t i l i t y i n postirradiation t e n s i l e and creep-rupture tests at elevated temperatures. 8, the '%(n,a)

These e f f e c t s are attributed t o t h e helium produced by

transmutation.

Many of the d e t a i l s of t h e r o l e of helium

i n metals have been reviewed by Harries,1째 and we have applied these

'H. E. McCoy, Influence of Several Metallurgical Variables on the Tensile Properties of Hastelloy N, ORNL-3661 (August 1964). 8W. R. Martin and J. R. Weir, "Wfect of Elevated Temperature Irradiation on t h e Strength and Ductility of t h e Nickel-Base Alloy, Hastelloy N," Nucl. Appl. 1(2), 160-67 (1965).

W. R. &&in and J. R. W e i r , "Postirradiation Creep and Stress3(3), 167 (1967). Rupture of Hastellay N," Nucl. Appl. -

'%. R. wries, "Neutron Irradiation Embrittlement of Austenitic Stainless Steels and Nickel-Base Alloys," J. B r i t . Nucl. Energy SOC. 5, 74 (1966). =:

iJ s

51 /'

ideas t o Hastelloy N i n two-recent papers. 11,12 Hence, we s h a l l not

discuss the mechanism whereby helium a l t e r s t h e properties.

There a r e some questions concerning the comparison o r thermal f l u x measurements

f o r the MSRE and Om. However, about 30 t o 40% of t h e

was transmuted

i n the surveillance specimens with a r e s u l t i n g atomic f r a c t i o n of helium of about 1 X lo+.

W e f e e l t h a t , a t l e a s t a t l o w s t r a i n rates, t h e

deterioration of properties s a t u r a t e s a t helium l e v e l s an order of magnitude lower.

Hence, t h e exact helium l e v e l i s r a t h e r academic, and the high-

temperature properties have probably s t a b i l i z e d unless cohtinued exposure

a t 650째C causes metallurgical changes t h a t a r e detrimental.

The drop i n

d u c t i l i t y a t low temperatures is somewhat surprising and bears watching.

;'F

i i

However, t h e d u c t i l i t y l e v e l s a r e s t i l l quite reasonable. \

The mechanical properties appear unaffected by the salt.

This i s

evidenced by the excellent agreement between t h e r e s u l t s of tests on

i i 1

materials i r r a d i a t e d i n t h e MSRE and t h e ORR (helium environment).

small amount of carburization t h a t occurred i n t h e Hastelloy N which was

!i i

i I 1

1 3

The

i n contact with graphite was not surprising and did not extend t o alarming depths. The very low stress l e v e l s i n t h e MSRE during normal operation, 13 coupled w i t h t h e experimental observation t h a t t h e deteriora$ion of t h e creep-rupture properties (rupture l i f e and d u c t i l i t y ) due t o i r r a d i a t i o n becomes smaller a t low stresses, indicate t h a t t r a n s i e n t conditions o f f e r

t h e greatest r i s k of f a i l u r e .

does not appear a t t h i s t i m e that the l i f e of t h e MSRE w i l l be limited by

Thus, w i t h reasonable care i n operation, it

radiation damage t o t h e Hastelloy N.

"H. E. McCoy, Jr., and J. R. Weir, Jr., In- and &-Reactor StressRupture Properties of Hastelloy N Tubing, ORNL-TM-1906 (September 1967). I ~

I I

"H. E. McCoy, Jr., and J. R. Weir, Jr., EFfects o f I r r a d i a t i o n on t h e Mechanical Properties of Two Vacuum-Melted Heats of Hastelloy N, ( t o be published).

13R. B. Briggs, private communication.

SUMbKRY 'AND CONCLXTSIONS

We have t e s t e d he first group of surveillance specimens from -he They were removed a f t e r 7800 Mwhr of operation during which

KSRE core.

t h e specimens were held a t 645 f 10째C f o r 4800 hr and accumulated a thermal dose of 1.3 X

lo2'

neutrons/cm2.

Specimens were exposed t o

molten salt t o d q l i c a t e t h e thermal history of t h e surveillance specimens.

Two heats of material, 5081 and 5085, were used with both sharing similar deterioration of t e n s i l e d u c t i l i t y a t elevated temperatures. However, heat 5085 (cylindrical core vessel) exhibited a greater loss of creeps

rupture strength and d u c t i l i t y .

!be property changes were quite similar

t o those that had been observed f o r these same materials after i r r a d i a t i o n i n the ORR where the environment was helium. reduction

iiz

There was a significant

t h e low-temperature d u c t i l i t y , but fracture s t r a i n s of

35 to 404 were s t i l l obtained.

This change i n properties i s probably

due t o the formation of intergranular MgC.

W e noted the formation of a carbon-rich layer on the Hastellay N where it was i n contact with graphite.

This layer was only 1t o 2 mils

deep and probably would have l i t t l e e f f e c t on the mechanical properties of thick sections.

S a c r i f i c i a l metal shims were placed i n the MSRF,

where the graphite and Hastelloy N were i n contact, s o the noted

carburization should present no problems i n the WFB.

The mechanical properties of t h e Hastellay N appear t o be quite adequate f o r the normal operating conditions of the M3RE.

However,

transients should be p r w e n t e d t h a t expose the material t o high stresses I

or s t r a i n s .

ACKNOWLEDGMENTS The author i s indebted t o numerous persons f o r assistance i n t h i s

Study.

W. H. Cook and A. Taboada

- Design of surveillance asselllbly and insertion of specimens.

W. H. Cook and H. B. Piper -Flux measurements. J. R. Weir, Jr., and W. H. Cook -Review of manuscript.

53 R. E. Gehlbach -Prepared t h e extraction replicas.

E. J. Lawrence and J. L. a r i f f i t h

- Assembled

survei'llance and control specimens i n fixture.

P. Haubenreich and WRE Operation Staff

- Ekercised

extreme care i n i n s e r t ing and removing t h e surveillance specimens.

E. M. King and Hot C e l l Operation Staff -Developed techniques f o r c u t t i n g long rods i n t o individual specimens, determined specimen straightness, and offered ass,istance i n running creep and t e n s i l e tests.

B. C. lillams, B.

kNabb, N. 0. Pleasant -Ran t e n s i l e and creep tests on surveillance and control specimens.

E. M. Thomas, V. G. Lane, and J. Feltner

- Processed t e s t

data.

H. R. Tinch and E. Lee -Metallography on control and surveillance specimens.

'Metals and Ceramics Reports Office -Preparation of manuscript. Graphic Arts

- Preparation

of drawings.

55 ORNL-TM-1997 INTERNAL DISTRIBUTION

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42. I

43. 44.

45. 46.

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55. 56.

57. S. J. D i t t o 58. A. S. D w o r k i n 59. 60. 61. 62. 63.

64. 65. 66. 67. 68. 69. 70. 71. 72. 73.

74. 75.

J. R. Engel

E. D. L. A. H. J. C. R. H. W. A. R. B. P. D.

76. C. 77. P. 78. F. 79. P. 80. J. 81-83. M. 84. H. 85. R. 86. T. 87. H.

88. W. 89. 90. 91. 92. 93. 94. 95. 96. 97. 98. 99. 100. 101. 102. 103. 1W.

P. R. M. M. C.

T. H. S. A. J. C. J. R. A. E. M.

P. Epler E. Ferguson M. Ferris P. Fraas A. Friedman H Frye, Jr. H. Gabbard B. Gallaher E. Goeller R. G r i m e s G. G r i n d e l l H. Guyman A. H a n n a f o r d H. H a r l e y G. Harman 0. Harms S. H a r r i l l N. H a u b e n r e i c h A. H e d d l e s o n G. H e r n d o n R. H i g h t o w e r R. H i l l W. H o f f m a n W. H o r t o n L. H u d s o n Inouye H. Jordan R. K a s t e n J. K e d 1 T. K e l l e y J. K e l l y R. K e n n e d y W. K e r l i n T. K e r r S. K i r s l i s I, Ki-akoviak W. K r e w s o n E. Lamb A. Lane B. Lindauer P. Litman L. h n g , Jr. I. Lundin

56 105. 106. 107. 108. 109. 110. 111. 112-116. 117.

won MacPherson MacF’herson Martin Mathews L. Matthews W. McClung E. McCoy, Jr. F. McDuffie K. McGlothlan J. McHargue E. McNeese S. Meyer L. Moore P. Nichols L. Nicholson L. C. Oakes P. Patriarca A. M. Perry H. B. Piper B. E. Prince J. L. Redford M. Richardson R. C. Robinson H. C. Roller M. W. Rosenthal H. C. Savage W. F. Schaffer C. E. Schilling Dunlap Scott

R. H. R. C. C. C. R. H. H. 118. C. 119. C. 120. L. 121. A. 122. R. 123. J. 124. E.

125. 126. I27.

128. 129. 130. 131. 132. 133. 134-138. 139. l40. 141. 142.

N. G. E. D. E.

Uf H. C. J. G. A. 148. F. 149. G. U O . 0. 151. P. 152. W. 153. I. 154. R. 155. H. 156. J. 157. E. 158. R. 159. J. 160. C. 161. ,B. 162. A. 163. J. 164. W. 165. K. 166. M. 167. J. 168. L. 169. G. 170. H.

143. 144. 145. 146. 147..

E. Sea’gren E. Sessions H. Shaffer M. Slaughter N. Smith J. Smith P. Smith L. Smith G. Smith F. Spencer Spiewak C. Steffy H. Stone R. Tallackson H. Taylor E. Thoma S. Watson F. Weaver H. Webster M. Weinberg R. W e i r , Jr. J. Werner W. West E. Whatley C. White V. Wilson Young C. Young

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187.

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J. D. H. A. J. F. C. W. W. T. A. D. G. D. R.

Giambusso, AEC, Washington L. Gregg, Bard Hall, Cornell University D. Haines, AM=, Washington E. Johnson, @, Washington L. Kittermn, AEE, Washington J. -kin, AEC, Oak Ridge Operations W. BkIntosh, AEC, Washington B. W i n , Atomics International G. Mason, Atomics International W. E y e r s , Atomics Internati6nal E. Reardon, AEC, Canoga Park Area Office M. Roth, AEC, Oak Ridge Operations

188. M. Shaw, AEC, Washington 189. 190. 191. 192. 193. 194. 195. . 196. 197-211.

U c

M. Simmons, AEC, Washington L. Smalley, AEC, Washington R. Stamp, AEC, Canoga Park Area Office K. Stevens, AEC, Washington R. F. Sweek, AEC, Washington A. Taboada, AEC, Washington R. F. Wilson, Atomics International , Laboratory and University Division, AEC, Oak Ridge Operations Division Technical Information Ektension

J. W. S. D.