U.S. regulatory recommendations for actinide-only burnup credit in transport and storage casks

In July 1999, the U.S. Nuclear Regulatory Commission (NRC) Spent Fuel Project Office (SFPO) issued Interim Staff Guidance 8 Revision 1 (ISG8R1) to provide recommendations for the use of burnup credit in storage and transport of pressurized-water reactor (PWR) spent fuel. Subsequent to the issuance of ISG8R1, the NRC Office of Regulatory Research (RES) has directed an effort to investigate the technical basis for extending the criteria and recommendations of ISG8R1 to allow improved implementation of burnup credit. This work sponsored by NRC/RES provided the reference material used by the NRC/SFPO to prepare Revision 2 of ISG8 (ISG8R2) that was released in September 2002. This paper discusses each of the six recommendations within ISG8R2 with specific emphasis on the changes implemented with ISG8R2 and the technical basis for the changes. (author)