CPR1000全厂断电叠加蒸汽发生器安全阀误开启事故引起的严重事故分析

利用MELCOR程序对CPR1000全厂断电叠加蒸汽发生器(SG)安全阀误开启事故引发的严重事故进行建模与分析，初步实现了对CPR1000严重事故进程的仿真计算与模拟。文中重点分析了无轴封泄漏和辅助给水、有轴封泄漏和辅助给水、有轴封泄漏但无辅助给水3种不同假设条件下CPR1000全厂断电严重事故的响应进程和结果。计算结果显示，SG安全阀误开启对事故进程有重要影响。在无轴封泄漏和辅助给水的情况下，压力容器在9576 s失效；当存在辅助给水时，压力容器失效延后近30000 s；而当存在轴封泄漏时，压力容器失效延后50 s左右。结果证明了发生全场断电叠加SG安全阀误开启事故情况下辅助给水和轴封泄漏对事故起到有效缓解作用。

Analysis of CPR1000 Severe Accident Induced by SBO With SG Safety Valve Stuck Open

The CPR1000 severe accident caused by station blackout (SBO) with the SG safety valve stuck open was modeled and analyzed using MELCOR code, and the simulation of CPR1000 severe accident process was preliminarily achieved. Three assumptions, namely without shaft sealing leakage and auxiliary feed water, with shaft sealing leakage and auxiliary feed water, and with shaft sealing leakage but without auxiliary feed water, were analyzed. The results imply that SG safety valve stuck open has great influence on the accident sequences. According to the calculation results, without shaft sealing leakage and auxiliary feed water, pressure vessel will fail at 9 576 s. When auxiliary feed water supplies, pressure vessel failure delays nearly 30 000 s. When the leakage of the shaft sealing system exists, pressure vessel failure will delay about 50 s. The results show that the auxiliary feed water and the leakage of the shaft sealing system have great mitigation effect on the severe accident induced by SBO with SG safety valve stuck open.