Analysis of shutdown technical specifications using the low power and shutdown risk model for the Surry Nuclear Power Plant

This paper describes a risk-based screening analysis that was performed on the Surry nuclear power station to evaluate the adequacy of technical specifications (TS) for the PWRs during shutdown periods. Of particular concern was the risk sensitivity to allowable TS configurations while at reduced reactor coolant system inventory conditions since incidents have occurred in plants over recent years during this time. A typical refueling outage was analyzed to determine the plant configurations created due to surveillance testing and maintenance activities. The impact from single and multiple component outages were identified so their risk influence on the plant configuration could be assessed. From these results, generic insights into the efficiency of existing TS to control high risk configurations were obtained as well as the applicability and ability of the risk-based methodology employed to make the determination