Risk-based configuration control: Application of PSA in improving technical specifications and operational safety

Risk-based configuration control is the management of component configurations using a risk perspective to control risk and assure safety. A configuration, as used here, is a set of component operability statuses that define the state of a nuclear power plant. If the component configurations that have high risk implications do not occur, then the risk from the operation of nuclear power plants would be minimal. The control of component configurations, i.e., the management of component statuses, to minimize the risk from components being unavailable, becomes difficult, because the status of a standby safety system component is often not apparent unless it is tested. Controlling plant configuration from a risk-perspective can provide more direct risk control and also more operational flexibility by allowing looser controls in areas unimportant to risk. Risk-based configuration control approaches can be used to replace parts of nuclear power plant Technical Specifications. With the advances in probabilistic safety assessment (PSA) technology, such approaches to improve Technical Specifications and operational safety are feasible. In this paper, we present an analysis of configuration risks, and a framework for risk-based configuration control to achieve the desired control of risk-significant configurations during plant operation