A short-term station blackout (STSBO) accident has been considered as one of risk dominant sequences for nuclear power plants (NPPs). Unless appropriate mitigation actions are not taken, a rapid damage of the reactor core and thereby a severe accident may result in. This paper presents best practice analysis results on the evolution of the severe accident sequences and fission product (FP) source terms expected during the STSBO accident of a reference pressurized water reactor. In addition, this study aims to analyze the impact of dedicated severe accident mitigation/management actions on the results of interest through the established modeling approach. As the modeling and simulation tools for the analysis, MELCOR2.2 and MAAP5.05, were used to compare the analysis results of interest such as the integrities of the reactor coolant system (RCS) pressure boundary and the reactor/containment building, the generation of flammable gases (such as hydrogen and carbon monoxide), and the environmental release of the FP cesium. As a key finding, this study demonstrated that both codes similarly predicted the environmental release of the FP cesium as well as the general trend of the evolution of the severe accident sequences and plant responses. Of particular interest was the substantial difference in predicting the generation of the flammable gases by the two codes. Relevant insights are summarized in terms of particular points of interest.

短期停电（STSBO）事故已被视为核电站（NPP）的风险主导序列之一。除非不采取适当的缓解措施，否则可能导致反应堆堆芯快速损坏，从而导致严重事故。参考压水堆的STSBO事故。此外，本研究旨在通过建立的建模方法来分析专门的严重事故缓解/管理措施对目标结果的影响。作为用于分析的建模和仿真工具MELCOR2.2和MAAP5.05，用来比较感兴趣的分析结果，例如反应堆冷却剂系统（RCS）压力边界和反应堆/防护建筑物的完整性，可燃气体（例如氢气和一氧化碳）的产生以及反应堆的环境释放FP铯。作为一项重要发现，这项研究表明，两个法规都相似地预测了FP铯的环境释放以及严重事故序列和植物反应的总体发展趋势。特别令人感兴趣的是，根据这两个规范，在预测可燃气体的产生方面存在实质性差异。根据特定的兴趣点总结了相关的见解。FP铯的环境释放。作为一项重要发现，这项研究表明，两个法规都相似地预测了FP铯的环境释放以及严重事故序列和植物反应的总体发展趋势。特别令人感兴趣的是，根据这两个规范，在预测可燃气体的产生方面存在实质性差异。根据特定的兴趣点总结了相关的见解。FP铯的环境释放。作为一项重要发现，这项研究表明，两个法规都相似地预测了FP铯的环境释放以及严重事故序列和植物反应的总体发展趋势。特别令人感兴趣的是，根据这两个规范，在预测可燃气体的产生方面存在实质性差异。根据特定的兴趣点总结了相关的见解。