Document: NRC Regulatory Guide
Document ID: 22ccfd5e-c5d8-4615-a02c-32369aa9f533
Document Type: regulatory_guide
Title: Acceptability of Probabilistic Risk Assessment Results for Risk-Informed Activities (Rev. 3)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1930/ML19308B636.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.200
CFR Part: 
CFR Title: 

Content:
ld not be considered an upgrade. Clarification . . . “new” should be interpreted as new to the subject PRA even though the methodology in question has been applied in other PRAs and includes newly developed methods that have been used in the base PRA by the analyst. It is not intended to imply a NDM. This interpretation . . . 1-A.2 An “internal review” is recommended in several places. This recommendation is made instead of an “outside” peer review. It needs to be made clear that this internal review is a type of “peer review” and should follow the process and requirements for the peer review requirements. Clarification (d) In the context . . . A focused review would be warranted. (e) When performing an internal review, the objective is to assess that the change to the PRA was correctly performed. In performing this assessment, the reviewer should use as guidance those applicable requirements in the standard. 1-A.3, Examples 8, 10, 17 It is assumed that a change to the base PRA that involves a calculation using the same computer code is a PRA maintenance type change rather than a PRA upgrade type change. This assumption would only be valid if the calculation does not involve any new assumptions and the same analyst is performing the calculation. Clarification Change: . . . . using the same computer code that was used for the prior calculations, given the calculation does not involve any new assumptions and the calculation is performed using the same guidance. NOTE: the words “that was used for the prior calculations” do not appear in Example #8, staff clarification includes these words in Example #8. DG-1362, Appendix A, Page A-7 Table A-1. Staff Position on ASME/ANS RA-Sa-2009 Part 1, General Requirements for an At-Power Level 1 and LERF PRA Index No Issue Position Resolution 1-A.3, Example 18 Changing the definition of core damage without changing the thermal- hydraulic methodology may result in changed success criteria which could change the