Level 1 risk analysis of low power and shutdown operations at a BWR. Phase 2, Results

This paper describes the current status of Phase 2 of the BWR Low Power and Shutdown Accident Frequencies Program being conducted at Sandia National Laboratories for the US Nuclear Regulatory Commission. The major focus of this phase of the project is a detailed analysis of potential accidents that could occur at Grand Gulf while in Cold Shutdown [Plant Operational State (POS) 5] during a refueling outage. POS 5 was selected for detailed examination based upon the results of the Phase 1 Coarse Screening Analysis, the results of which were presented at the Nineteenth Water Reactor Safety Information Meeting. A summary of the project including results and insights from Phase 2 is presented.