Abstract In a liquid-fueled molten salt reactor (MSR), the fuel salt acts as both fuel and coolant, and the fission energy is released into the fuel salt immediately. The delayed neutron precursors drift through the graphite channels in the core and the primary loop during operation. Therefore, the dynamics for a MSR is characterized by the strong interplay between the neutronics and thermal hydraulics, which is significantly different from that of a solid-fueled reactor, such as PWR. In this study, a dynamic analysis for a graphite moderated, fluoride based, liquid-fueled molten salt reactor with a power of 2 MWth (TMSR-LF) is carried out based on a coupled neutronics/thermal hydraulics code named TMSR-2D. The steady-state characteristics including the distributions of flow field, temperature and neutron fluxes, and effective delayed neutron fraction under different fuel flow rates, transients perturbed by fuel pump start-up and coast-down, overcooling and overheating of inlet fuel and reactivity insertion are simulated and analyzed. The numerical results indicate that the dynamic behavior of TMSR-LF is acceptable in the aspect of reactor safety. Furthermore, the dynamic analysis offers valuable information for future construction and operation of this experimental reactor.

中文翻译：

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2 MW液体燃料熔盐反应堆的动力学分析

摘要 在液态燃料熔盐反应堆（MSR）中，燃料盐既是燃料又是冷却剂，裂变能立即释放到燃料盐中。延迟中子前体在运行期间漂移通过核心和初级回路中的石墨通道。因此，MSR 的动力学特点是中子学和热工水力之间的强烈相互作用，这与固体燃料反应堆（如压水堆）的动力学有很大不同。在这项研究中，基于名为 TMSR-2D 的耦合中子学/热工水力学代码对功率为 2 MWth 的石墨慢化、氟化物基液体燃料熔盐反应堆 (TMSR-LF) 进行了动力学分析。稳态特性包括流场分布、温度分布和中子通量分布，模拟分析了不同燃料流量下的有效延迟中子分数、燃料泵启动和惯性停机、入口燃料过冷和过热以及反应性插入所扰动的瞬态。数值结果表明，TMSR-LF的动力行为在反应堆安全方面是可以接受的。此外，动态分析为该实验反应堆的未来建设和运行提供了有价值的信息。