钍基熔盐核能系统

Safety analysis of graphite core in molten salt test

reactor Derek Tsang

SINAP

16.09.2013

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!