液态熔盐堆运行安全特性初步研究

液态燃料反应堆与固态燃料反应堆相比，原理上有较大不同。液态熔盐堆中由于燃料流动带走缓发中子先驱核在堆外衰变导致堆芯反应性降低，且裂变产物在堆外回路中衰变也会引起一回路发热。本文使用熔盐堆中子动力学程序Cinsf1D探讨2 MW熔盐堆的临界动力学特性和安全特性，研究零功率临界下不同熔盐流速启泵和停泵导致的缓发中子先驱核流失所需改变的控制棒棒位。同时还计算了2 MW恒定功率情况下稳态运行及降低流速时一回路温度分布，并模拟了2 MW额定功率下停泵事件。停泵后由于缓发中子损失减少反应堆功率先缓慢增加，然后迅速降低到接近余热水平。停泵后堆芯温度缓慢增加后稳定在安全值以内，说明熔盐堆具有本征安全性。

Preliminary Study on Safety Characteristics of Molten Salt Reactor

Compared with solid fuel reactors, there are differences in physics for liquid fuel reactor. As for molten salt reactor (MSR), due to fuel flow in primary loop, the delayed neutron precursors and fission product partly decay out of core, resulting in reactivity loss as well as heat generation in the primary loop. In this paper, the critical dynamics and safety characteristics of MSR were investigated using Cinsf1D code. Considering the loss of delayed neutrons under different fuel flow speeds at zero-power, the corresponding control rod positions were calculated under pump start and stop conditions. Keeping reactor power at 2 MW, the temperature and power were computed for the primary loop system. Finally, the pump stop accident was simulated from rated power 2 MW. After pump stop, the reactor power increases slightly due to the reduction of delayed neutron loss at initial time and then it decreases to approach the decay heat power level quickly. The temperature in core increases slowly and reaches to a balance within safety range. It can be concluded that MSR has intrinsic safety.