风险指引的核电站设备分级概述

Review of the Risk-Informed Categorization of NPPs

核电站的构筑物、系统及设备(以下简称SSC)的安全分级是核电站各项管理要求和规定的基础。由于传统确定论分级自身的特点,使基于此分级的核安全法规,一方面对设备的处理上存在过度的保守性,另一方面又在某些方面存在不够保守的地方。为了使法规对设备处理要求的规定更趋于合理,因此有了风险指引设备分级思想的产生。美国核管会及一部分业主对此分级思想的前景持肯定态度,并制定了多项相应的法规、标准及导则,同时有少数业主对此分级方法进行了试点性的研究。这些举措都将促进该风险指引设备分级思想的发展。通过总结与此分级相关的背景、方法及案例研究,对比传统分级和风险指引的分级方法之间的异同,阐述风险指引分级的方法论,使读者对风险指引分级思想的现状及发展有一个总体的概念,并对其以后的发展提出一些展望。

The categorization of Structures, Systems and Components （SSC） is one of the cornerstones in the design of the nuclear power plant. The regulation requirements based on the current deterministic categorization are over-conservative in some aspects, and on the contrary, some other requirements are too loose. In order to make the requirements reasonable, the risk-informed categorization of SSCs has been presented. USNRC and some owners affirm that this categorization method is available. Therefore, related requirements, standards and guidelines have been established by USNRC, and on the other hand, some pilot studies have been made by those owners. In this paper, we summarized the background, methods and pilot studies related to this categorization. The relationship and difference between the two methods： exiting deterministic one and the risk-informed one are compared, and the methodology about risk-informed categorization is illuminated. In this way, we expect that the readers have an overview about the current status about risk-informed categorization and bring forward some prospects about its development.