Document: NUREG-0800
Document ID: 05908428-2f08-4a4f-8512-996c29c86da8
Document Type: srp
Title: have been revised to address Addendum B of the ASME standard and the revised NEI
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0717/ML071700657.pdf
Revision Date: 2023-06
Chapter: 19
Section ID: 19.1
CFR Part: 
CFR Title: 

Content:
the SSCs, operator actions, and plant operational characteristics affected by or important to the application • a description of the cause-effect relationships between the change and the above SSCs, operator actions, and plant operational characteristics (when applicable, e.g., for licence amendment applications) • mapping of the cause-effect relationships onto PRA model elements (when applicable) • definition of the acceptance criteria or guidelines, including identification of the PRA results that will be used to compare against the acceptance criteria or guidelines and how the comparison is to be made. 19.1-6 Revision 2 - June 2007 III.1.2 Scope of Risk Contributors Addressed in the PRA Model Based on the definition of the application, the scope of risk contributors (internal and external initiating events, modes of plant operation) of the PRA can be identified. For example, if the application is designed around using the acceptance guidelines of Regulatory Guide 1.174, the evaluations of core damage frequency (CDF), the change in CDF (ΔCDF), large early release frequency (LERF), and the change in LERF (ΔLERF) should be performed with a full-scope PRA, including external initiating events and all modes of operation. However, since most PRAs do not address this full scope, the decision makers must make allowances for these omissions. Examples of allowances include the introduction of compensatory measures, restriction of the implementation of the proposed change to the aspects of the plant covered by the risk model, and use of bounding arguments to cover the risk contributions not addressed by the model. This SRP section does not address this aspect of decision making but is focused on what information should be provided. The reviewer’s responsibility is to understand the scope of the PRA used in the decision making so that the appropriate appendices to Regulatory Guide 1.200 are identified as references for the review. III.1.3 Parts of the PRA Model