New Design of Thorium Molten Salt Reactor Core and Preliminary Safety Analysis

In order to improve the breeding ratio and core safety, new thorium molten salt reactor (TMSR) core is designed. The new designed TMSR core is composed of hexagon moderator elements, which contain SiC tube to form a central fuel channel and employs BeO as moderator. The composition of the fuel salt, adopted in this core, is also optimized. Based on this core design, steady state and transient safety characteristic of TMSR are preliminarily analyzed using coupled multi-physics code. Power/temperature distribution and reactivity coefficients are analyzed for the steady state core, which demonstrated that the core has flat temperature distribution and large negative power coefficients at all power level. Transient simulations are carried out for power start-up, pump speed variation, loss of heat sink and so forth, the temperature and power response are also analyzed. The results indicate that the TMSR core power and temperature are closely related to the control rod position, velocity of flow and composition of fuel salt, and the new designed TMSR has excellent performance of safety under various operating conditions.