AP1000核电厂应对全厂断电事故的稳压器防满溢对策研究

AP1000核电厂若在全厂断电事故下丧失正常给水，会引起稳压器满溢，将通过稳压器安全阀排放液体冷却剂，引起反应堆冷却剂水装量流失，增大反应堆堆芯裸露的风险。与此同时，安全壳内的放射性水平因稳压器满溢可能会增大，增大向环境排放大量放射物质的可能。为防止稳压器满溢，本工作进行了解决或缓解稳压器满溢的对策研究。结果表明，增大非能动余热排出系统（PRHRS）热交换器的传热面积，可防止稳压器满溢；合理降低安全壳内置换料水箱（IRWST）的背压，可增大达到稳压器满溢的裕度，有效地缓解稳压器满溢；增大稳压器的自由容积，可防止稳压器满溢。此结论对AP1000核电厂的设计和事故分析有一定的参考作用。

AP1000 Plant Pressurizer Overfilling Prevention Study Against Station Blackout Accident

If loss of main feed-water occurs in a station blackout accident for AP1000 plant, the pressurizer will overfill and the coolant will be discharged through pressurizer safety valves. It results in a loss of coolant accident, RCS inventory will decrease, and the risk of reactor core uncovering increases. Because of the coolant discharging, the atmosphere radiation level in the containment may be raised, while the possibility of radioactive release to the environment increases. In order to prevent pressurizer overfilling, an effective strategy to avoid and mitigate pressurizer overfilling was provided. The results show that increasing heat transfer areas of PRHRS heat exchanger can prevent pressurizer overfilling; reasonable decreasing of IRWST back pressure can enhance margins of pressurizer overfilling, and mitigate pressurizer overfilling phenomena; increasing pressurizer volumes can also avoid pressurizer overfilling. The conclusions have reference value in helping design and safety analysis of AP1000 plant.