Converting the IPE to a full-scope shutdown risk model

it is now well recognized that conditions occurring during plant shutdown can result in relatively high levels of risk. Southern California Edison (SCE) has for several years sought to manage risks during refueling outages by performing probabilistic evaluations of outage plans using [open quotes]risk-based failure modes and effects analyses[close quotes] to determine the likelihood of both fuel damage and inventory heatup events. In an effort to assess its shutdown risks in as much detail as was done in its recently submitted individual plant examination (IPE), SCE performed a wholesale conversion of its IPE into a full-scope level-1 shutdown probabilistic risk assessment (PRA). With assistance from ERIN Engineering, this effort resulted in a shutdown risk model for the San Onofre nuclear generating station that has become an effective and efficient tool for managing shutdown risk.