钠冷快堆反应性意外引入事故时停堆保护研究

Research on Shutdown Protection of Sodium-cooled Fast Reactor for Reactivity Accident Introduction

在反应堆系统中,当反应堆处于异常工况时,如果运行参数超出保护限值,则由保护系统触发相关保护动作,以保证反应堆的状态符合事故验收准则的要求。本文将通过Simulink建立钠冷快堆主要系统模型,在发生反应性意外引入事故时,借鉴快堆事故分析中预期瞬态无停堆保护(ATWS)的分析方法,基于相应保护参数的测量误差和数据处理过程对反应堆一回路的保护参数及其整定值进行研究,并确保钠冷快堆的状态在整个反应性引入事故过程中符合钠冷快堆的事故验收准则。仿真结果表明,当发生补偿棒失控提升5 s和10 s时,目前的堆芯出口钠温、功率、功率流量比等保护参数的整定值、信号测量延迟及落棒时间可取其他值。当补偿棒失控提升15 s时,只要保证保护参数整定值、相应参数的信号测量延迟及落棒时间能使反应堆在36.45 s前进入深度次临界都是可以的。

In the reactor system,when the reactor is in abnormal condition,if the operation parameters exceed the protection limit,the relevant protection actions will be triggered by protection system to ensure that the state of the reactor meets the requirements of the accident acceptance criteria.The main system model of sodium-cooled fast reactor was established by Simulink in the paper.For reactivity accident introduction,the protection parameters and their setting values of the primary loop of the reactor were studied based on the measurement error and data processing of corresponding protection parameters,in the same manner as anticipated transient without scram(ATWS)for fast reactor analysis,and the state of the sodium-cooled fast reactor met the accident acceptance criteria for sodium-cooled fast reactor during the entire reactivity accident introduction.The results show that the current setting values of protection parameters,such as sodium temperature at core outlet,power and power-flow ratio as well as the signal measurement delay and the falling time of the rod can be taken from other values,when the shim rod is accidentally lifted for 5 s or 10 s.While for 15 s,as long as the setting value of the protection parameter,the signal measurement delay of the corresponding parameter and the falling time of the rod can make the reactor enter the depth subcritical before 36.45 s,the state of the reactor will still meet the requirement of the accident acceptance criteria.