In 2012 a review and comment ballot containing requirements for use of the Standard on ALWRs was issued. The ballot is based on the ASME/ANS PRA Standard (i.e., RA-Sa-2009). The ballot was developed by the Joint Committee on Nuclear Risk Management (JCNRM) working group (WG) on ALWRs. Based on the charter of the working group and stakeholder interest, Parts 1 through 5 of the Standard have been addressed. Thus, address internal events at power, internal flooding at power, internal fires at power, and seismic at power have been addressed. Other external events started in 2012 and will be balloted in 2013. Low power and shutdown (LP/SD) modes, and Level 2 PRA and Level 3 PRA Standards (when they are available) will then be considered. A formal ballot for Parts 1 through 5 is planned for 2013. This paper provides the approach and results.
The mandatory appendix is important because an ALWR plant in the preoperational cannot meet the standard as written, and the US NRC expects that the PRA will meet the Standard. Thus changes are needed to the standard to address the differences in preoperational and operational plants and the differences in current generation and ALWR plants. This will assist vendors and licensees in successfully developing PRAs to meet US NRC requirements.
