本标准仅限于分析从堆芯损坏开始到放射性核素释放到环境或确定不会发生释放到环境的严重事故的进展。它包括对反应堆容器、安全壳结构和可能参与辐射释放到环境中的相邻结构内部发生的各种现象的分析。该分析涉及通过概率逻辑结构（如安全壳事件树（CET）（或等效物））携带假定的事故序列，并确定放射性核素释放特征（e。 g、 ，幅度和时间）的各种途径通过大学英语四级考试。本标准包括从反应堆运行的所有模式（在功率、停堆和过渡状态下）引发的假定事故序列。它还包括ASME/ANS RA-Sa-2009《核电厂应用1级/大提前释放频率概率风险评估标准》中所述的内部事件和/或外部危害引发的事故序列。

This standard is limited to analyzing the progression of severe accidents from the onset of core damage through radionuclide release to the environment or a determination that a release to the environment will not occur. It includes the analysis of the various phenomena that occur inside the reactor vessel, the containment structure, and neighboring structures that might participate in the radiological release pathway to the environment. This analysis involves carrying the postulated accident sequences through a probabilistic logic structure such as a containment event tree (CET) (or equivalent) and determining the radionuclide release characteristics (e.g., magnitude and timing) for the various pathways through the CET. This standard includes postulated accident sequences initiated from all modes of reactor operation (at-power, shutdown, and transition states). It also includes accident sequences initiated by internal events and/or external hazards addressed in ASME/ANS RA-Sa-2009, Standard for Level 1/Large Early Release Frequency Probabilistic Risk Assessment for Nuclear Power Plant Applications.