Preliminary neutronic and thermal-hydraulic analysis of a 2 MW Thorium-based Molten Salt Reactor with Solid Fuel

• A detailed core model of China 2 MW Thorium Molten Salt Reactor with Solid Fuel (TMSR-SF) is developed using MCNP-4C.
• Core physics parameters such as power density distribution, reactivity coefficients and kinetic parameters are obtained.
• Four basic transient conditions are investigated by a home-made code for the 2 MW TMSR-SF, which indicates its inherent safety.

The Fluoride-salt-cooled High temperature Reactor (FHR) is an advanced concept combining attractive attributes by adopting low pressure liquid salt, high temperature coated particle fuel and air-Brayton combined cycle. 2 MW Thorium-based Molten Salt Reactor with Solid Fuel (TMSR-SF) designed by Shanghai Institute of Applied Physics (SINAP) as a test reactor is planned to be constructed. In this paper, the preliminary neutronic and thermal-hydraulic analysis of the TMSR-SF is performed. The neutronic investigation is conducted by developing a validated 3-D model for the reactor with MCNP-4C. Core physics parameters of TMSR-SF including the effective multiplication factor, neutron flux distribution, power density distribution, control system worth, reactivity coefficients and kinetics parameters are obtained, which are used as input parameters for the thermal-hydraulic analysis of the TMSR-SF. The FHR Safety Analysis Code (FSAC) is extended to study the safety characteristics of the TMSR-SF by simulating four types of basic transient conditions including the unprotected loss of flow (ULOF), unprotected overcooling (UOC), unprotected transient overpower (UTOP) and the combination of ULOF and UTOP. The results show that the concept design of TMSR-SF is an inherently safe design with no temperature limits exceeded in the analyzed transient conditions.