Matters concerning the improvement of safety guidelines related to the use of risk-informative methods in determining the safety class of elements of nuclear power plants in the process of design and assessment of malfunctions are considered. Clarifi cations of the terms and defi nitions used are proposed. Considerable attention is given to the interpretation and calculation of the conditional probability of a severe accident in the event of a single failure of an NPP element and disruptions characterized by a complex of failures. Relations are given for calculating the indicated probability in terms of signifi cance indicators for the elements (complex of elements) of NPP. Proposals are formulated to clarify the criteria for the classifi cation of disruptions of operation, taking into account the guidelines presented in the top-level regulatory documents. The proposed indicator ensures that the assessment methods used for different types of disturbances are consistent. Recommendations for improving the risk-informative approach to decision-making during NPP operation are described.

审议了有关改进与在设计和评估故障过程中使用风险信息方法确定核电厂要素的安全等级有关的安全导则的事项。建议澄清所使用的术语和定义。在核电厂元件的单一故障和以复杂故障为特征的中断事件中，对严重事故的条件概率的解释和计算给予了相当大的关注。给出了计算 NPP 元素（元素的复合体）显着性指标的指示概率的关系。制定提案以明确运营中断的分类标准，考虑到顶级监管文件中提出的指导方针。建议的指标确保用于不同类型干扰的评估方法是一致的。描述了改进核电厂运行期间决策的风险信息方法的建议。