百万千瓦级核电厂停堆工况下的概率安全评价

Probabilistic Safety Assessment to 1000 MW PWR Plant during Shutdown State

对百万千瓦级核电厂停堆运行事故进行内部事件1级概率安全评价(PSA),根据不同的停堆进程分别建立停堆PSA模型,分析经历余热排出系统(RRA)低运行区间(LOI-RRA)水位对电厂风险水平构成的影响;同时采用事故系列先兆标准电厂风险分析模型人员可靠性分析(SPAR-H)方法进行人员可靠性分析,评价其定量化结果的适用性。分析结果表明,停堆工况下的电厂风险不可忽视,在停堆工况下的事故规程有待完善之处,冷停堆工况下由LOI-RRA水位导致堆芯损坏频率明显增加,人因失误是造成停堆高风险的关键因素。

This paper initiates a study focused on level 1 Probability Safety Assessment （PSA） for shutdown operation at 1000MWe PWR. Shutdown PSA models considering different plant outage types are constructed respectively to evaluate the risk of LOI-RRA operation. The application of SPAR-H method is also evaluated. The results show that the potential risk during shutdown should not be ignored; PSA for shutdown states could help to prompt the improvement in procedure to reduce the risk in shutdown condition. Going through the LOI-RRA operation at cool shutdown refueling outage significantly increases the plant risk; the dominant factor contributing to CDF is human error,