对CAP1400安全壳有效性的进一步研究

Further Study on Containment Effectiveness for CAP1400

摘要: 堆腔淹没失效将导致安全壳失效，是CAP1400二级概率安全评价(PSA)安全壳有效性分析中的一个保守假设。为更大程度地体现安全壳设计和严重事故缓解措施对安全壳有效性的贡献，对该假设进行了探讨。通过梳理CAP1400能够用于应对堆外严重事故现象的现有设计特性，以扩展事件树的方式评估了CAP1400示范工程安全壳在蒸汽爆炸、熔融物-混凝土相互作用等主要堆外事故进程中保持完整性的概率，进一步研究了CAP1400示范工程安全壳的有效性。重新评估的CAP1400示范工程安全壳有效性结果有较明显的提高，这对论证CAP1400示范工程满足“十三五”新建核电要求也起到了促进作用。

Abstract: One of the conservative assumptions in level two PSA analysis of CAP1400 containment effectiveness is that failure of cavity flooding leads to failure of containment. A discussion was made on this assumption in order to further demonstrate the contribution of containment design and severe accident mitigation features to containment effectiveness. By sorting out the CAP1400 design features that can be used to cope with ex-vessel severe accident phenomena, in a way of expansion of containment event tree probability was assessed, whether CAP1400 containment can maintain integrity during the ex-vessel process such as steam explosion and core-concrete interaction. Therefore containment effectiveness for the first CAP1400 unit was further studied. The result shows that reassessed effectiveness was relatively enhanced and promoted demonstration that the first CAP1400 unit fulfilled the safety goal for new-constructed units required by the thirteenth Five-Year Plan.