次临界或低功率启动工况下控制棒组失控抽出事故DNBR裕量分析

次临界或低功率启动工况下控制棒组失控抽出事故定义为RCC-P Ⅱ类事故，它一直是核电厂安全分析的极限事故之一。本文以典型三环路压水堆为对象，分析了热停堆状态下不同停堆棒组组合对该事故DNBR裕量的影响。研究表明，通过优化热停堆状态下停堆棒组组合，在保证足够的停堆深度下，可进一步提高典型三环路压水堆核电厂在该事故下的DNBR裕量。

DNBR Margin Analysis for Uncontrolled Withdrawal of Rod Cluster Control Assembly Bank From Subcritical or Low Power Startup Condition

Uncontrolled withdrawal of rod cluster control assembly bank from a subcritical or low power startup condition is classified as a RCC-P condition Ⅱ event and always one of the most limiting events in the safety analysis for the nuclear power plant. Based on typical three-loop PWR, the effects of different initial arrangements of the shutdown banks at the hot-shutdown state on the DNBR margin were studied. The results show that the DNBR margin is further increased by optimizing the initial arrangements of the shutdown banks at the hot-shutdown state in order to assure the enough shutdown margins.