Abstract
In January 2007, the NRC issued Revision 1 to Regulatory Guide (RG) 1.200 endorsing Addendum B of the ASME PRA Standard, RA-Sb-2005. Effective January 1, 2008, the probabilistic risk assessment (PRA) supporting any risk-informed application must comply with the requirements of RG 1.200 and the ASME PRA Standard, as explained in NRC’s Regulatory Issue Summary (RIS) 2007-06. Per Section 6 of the ASME PRA Standard, a peer review must be performed to demonstrate compliance with the ASME PRA Standard. In the late 1990s, all nuclear plants in the U. S. had a peer review performed in accordance with NEI 00-02. However, the ASME PRA Standard requirements are more extensive than the review elements in NEI 00-02. Appendix D of NEI 00-02, endorsed by Appendix B of RG 1.200, includes a self-assessment process for using the NEI 00-02 results to, in part; assess a PRA’s compliance with the ASME PRA Standard. The ASME PRA Standard requires a peer review for any PRA element that has been upgraded since the original peer review. There is also the consideration that if the PRA updates have resulted in enough changes to the model that the current model no longer is adequately represented by the model that was originally peer reviewed, then, at their discretion, the utility may request a new peer review. Both the Boiling Water Reactor Owners Group (BWROG) and the Pressurized Water Reactor Owners Group (PWROG) have authorized projects to conduct the peer reviews against RG 1.200, Revision 1 to support risk-informed applications after January, 2008. Two key elements have changed since the original NEI 00-02 peer reviews. These are: (1) the number of specific requirements that need to be reviewed and (2) the need for the utility undergoing a peer review to complete a self-assessment and a roadmap to the documentation supporting their assessment to enable the peer review team to complete their review within a reasonable timeframe. Since the original approval of the ASME PRA Standard in 2003, many plants have performed self-assessments either internally or with the assistance of contractors to ascertain their compliance with the ASME PRA Standard. A number of lessons have been learned as a result of these self-assessments that should be carried forward to the next round of formal peer reviews against Addendum B of the ASME PRA, RA-Sb-2005. This paper examines some of the lessons learned while performing these self-assessments, and provides some guidance for a pre-review self-assessment and as well as some guidelines on compiling a roadmap to support the self-assessment and the peer review.
Published Version
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