Safety analysis of graphite core in molten salt test reactor Derek Tsang SINAP 16.09.2013
钍基熔盐核能系统
Introduction v The Chinese Academy of Sciences (CAS) has launched a Thorium Molten Salt Reactor (TMSR) research project in 2011. v 350M USD for 5 years v To develop generation IV molten salt reactors. v Multipurpose applications of high temperature nuclear energy. v To build two molten salt test reactors between 2015 and 2017. v A CAS center for TMSR research has been set up at the Shanghai Institute of Applied Physics (SINAP) to lead the project.
• SINAP has a light source: Shanghai Synchrotron Radiation Facility (SSRF) • 150 MeV Linear accelerator. • 3.5 GeV Booster, 180m circumference • 3.5 GeV Storage Ring, 432m circumference • Number of Cells = 20
Introduction v Two types of molten salt reactors: v Molten salt and molten salt-cooled reactor.
v Molten salt reactors use salt as fuel and coolant v Molten salt-cooled reactors use TRISO fuel and salt as coolant only. v Molten salt reactors may have a fully closed fuel cycle, however, online reprocessing is challenging. v Molten salt-cooled reactors have a once-through fuel cycle, however, have high temperature and efficiency.
Molten salt coolant v Coolant salt has v Good thermal conductivity v High boiling point v Nuclear system can operate at much lower pressure than high temperature gas cooled reactor
v High melting point v Trap fission products in an accident
v Large heat capacity v During accident the temperature of the core rises slowly
10MW salt-cooled test reactor v TMSR SF1 v Built around 2015~2016 v Aims: v To gain experiences on design, construction and operation v To validate models, analyses and codes v To test the equipment and safety features v To accumulate operation data for larger-size reactors design and licensing
10MW salt-cooled test reactor v TRISO is used as nuclear fuel v 6cm diameter fuel pebbles
v Graphite is used as moderator and reflector v Primary coolant is FLiBe salt v Operating temperature is between 600°C and 650 °C v Core dimensions is 2.6m(dia.) x 3.0m(h)
10MW salt-cooled test reactor
Challenges for the 10MW test reactor & Reactor licensing Ø No molten salt-cooled or molten salt reactor has been licensed in China before Ø The regulators in China have limited exposure to either molten salt-cooled or molten salt reactor.
& Stress analysis & Material properties & Irradiation data
Graphite stress analysis v Density of graphite: 1.77g/cm3 v Density of molten salt: 1.99g/cm3 v Buoyant force acts on graphite bricks! v Graphite bricks must be constrained within the core! v Solid liquid interaction
Graphite problems v Molten salt may penetrate into graphite. v Modify graphite material properties?!? v How to measure Young’s modulus with molten salt at high temperature: v Dynamic method v Static method
Graphite Irradiation program v Measure irradiated graphite material properties v Young’s modulus v CTE v Dimensional change v Thermal conductivity v Tensile strength v Compressive strength
v With and without molten salt.
Graphite experiments v Shaking table 2m x 2m v Seismic test on graphite component
Thank you!