Document: NUREG-0800
Document ID: ac43f632-9db1-4857-9f56-bfba45965456
Document Type: srp
Title: * These are modifications to a plant’s design, operations, or other activities that require NRC approval. These modifica
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0232/ML023250195.pdf
Revision Date: 2023-06
Chapter: 19
Section ID: 19
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CFR Title: 

Content:
between systems and operator actions needed for accident mitigation. Proposed changes to the plant's design or operations could affect these dependencies; therefore, the evaluation of the risk change should also consider system-operator dependencies. However, since the modeling of these dependencies requires detailed knowledge of the plant systems and procedures, it will not be practical (nor is it intended) for reviewers to verify that all dependencies have been included in the change evaluation. Instead, reviewers should verify that the evaluation used a comprehensive and systematic process to look for these dependencies. Reviewers should rely on their experience with similar change analyses (when applicable) or with PRAs of similar plants, but should be aware that dependencies are in many cases plant-specific and will depend on plant-specific system capabilities and interactions, procedural guidance, and timing of potential accident sequences. SRP 19-A8 b. Review Guidance and Procedures Review guidance in this section consists of a discussion of the dependencies that could be important and that could be affected by changes to the plant’s design or operations. Although most changes will not alter the original PRA dependent failure analysis, some design or procedure changes could introduce new dependencies or affect existing ones. Therefore, reviewers should be cognizant with regard to the following types of dependencies that could exist and could affect the results of the change analysis: Functional Dependencies: These dependencies occur because the function of one system or component depends on that of another system or component. Functional dependencies include interactions that can occur when the change in the function of a system or component causes a physical change in the environment that results in the failure of another system or component. Functional dependencies include the following examples: • Shared component dependencies (e.g., systems or system