Risk managed technical specifications

Abstract

Application of probabilistic risk assessment (PRA) technology has become an essential component in the decision-making processes associated with the operation and regulation of commercial nuclear power plants (NPPs). As PRA technology has matured, it increasingly has been utilized to provide risk insights in the support of both operational and regulatory decision-making. This paper describes the next significant application of PRA technology to risk inform NPP operation. This Risk Managed Technical Specification (RMTS) application utilizes the results of the plant PRA to determine risk-informed technical specification (TS) allowed out of service times (AOTs). The RMTS process utilizes the PRA results to specify appropriate configuration specific TS AOTs and ensures the risk of events that could result in core damage or large early release are maintained below acceptable levels. In addition, RMTS requires development of integrated risk management actions to actively mitigate risks associated with the inoperability of TS structures, systems and components (SSCs). RMTS has been approved for implementation at commercial NPPs in the United States with the South Texas Project Electric Generating Station (STPEGS) serving as the initial application. In this paper we describe the programmatic requirements necessary to implement RMTS and provide several examples illustrating its application; thus demonstrating the applicability of RMTS to manage nuclear safety risk while simultaneously enhancing operational flexibility.