Document: NUREG-0800
Document ID: e32f0820-4e33-476e-aa36-4ca8c2c64af0
Document Type: srp
Title: Use of Probabilistic Risk Assessment in Plant-Specific, Risk-Informed Decisionmaking:
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0119/ML011940192.pdf
Revision Date: 2023-06
Chapter: 19
Section ID: 19.0
CFR Part: 
CFR Title: 

Content:
t should also include an evaluation of the licensee's process for modeling the system change as well as a spot-check of the revised system models and results. Reviewers should verify that, in modeling the change, the licensee appropriately modified the system logic models to reflect changes in the plant's configuration including changes to the system design, system performance characteristics, system alignments, operational procedures, and operational philosophies. In particular, reviewers should address the following considerations: The analysis of the change should account for the effects of the change on the definition of system success. That is, if the proposed application affects component configurations, expected operability conditions, failure modes and their effects, and alternative success and potential failure paths, these should be taken into account. In addition, the licensee should show that the justification used in the original analysis to exclude components, component failure modes, or flow diversion paths, etc. remain valid in light of the proposed change. The analysis should also identify and account for changes that could affect environmental conditions that could cause system failure (e.g., room temperature, containment pressure, etc.). The analysis should account for interfaces with other systems and dependence on support functions; this is particularly important if dependencies on motive power, control power, component cooling, room cooling, or any interlocks have been altered by an application. Other dependencies that licensees should consider include the dependency on automatic system initiation and the conditions that must exist for automatic start, essential manual actions to initiate or control the system, and the resources required to fulfill mission success (e.g., water sources, air, fuel oil, etc.). When applicable, licensees should factor these dependencies into the analysis of the change. When proposed changes deal with proceduralized