钠冷快堆停堆保护方案研究

在借鉴中国实验快堆（CEFR）热工模型建模经验的基础上，利用Relap5程序建立霞浦示范快堆（CFR）的主要系统模型，并参考快堆安全分析中的预期瞬态无停堆保护（ATWS）的分析方法，对发生反应性意外引入事故时的安全裕度和停堆保护进行仿真研究。仿真结果表明，额定功率下发生反应性引入时，不会触发短周期的报警和停堆；当发生补偿棒失控提升5 s和10 s时的反应性意外引入事故，目前一回路保护参数整定值、信号测量延迟及安全棒落棒时间可以取其他值；当补偿棒失控提升15 s时，在目前的设计下，核功率和功率流量比信号能确保事故下的反应堆状态符合事故验收准则。当其他保护信号失效，堆芯出口钠温所触发的停堆保护若要实现同样的功能，则需保证反应堆在14.85 s之前进入深度次临界。 

Research on Shutdown Protection Scheme for Sodium Cooled Fast Reactor

Based on the modeling experience of CEFR thermal-hydraulics model, the main system model of CFR is established through Relap code. According to the Anticipated Transient without Scram(ATWS) in the safety analysis of the fast reactor, the safety margin and shutdown protection in the event of reactivity accident introduction are studied. The results show that when the accident occurred at rated power, the alarm and shutdown signal of short-period was not triggered. Besides, the current setting value of each protection parameters in the primary loop, the signal measurement delay and drop time of scram rod can be taken from other values, when the reactivity insertion accident of uncontrolled shim rod withdrawal for 5 s or 10 s occurs. While for 15 s, the power and P/F signal can ensure that the reactor status meets the requirements of the accident acceptance criteria in the current design. To achieve the same function for shutdown protection triggered by sodium temperature at core outlet, it is necessary to make sure that the reactor is in depth subcritical before 14.85 s when the other protection signals fail.