Document: NUREG-0800
Document ID: 7916b088-fb90-4163-84fe-027bd315bcc5
Document Type: srp
Title: REVIEW OF RISK INFORMATION USED TO SUPPORT PERMANENT PLANT-
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0717/ML071700658.pdf
Revision Date: 2023-06
Chapter: 19
Section ID: 19.2
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Content:
well as the equipment required to perform the specific function associated with the action. The equipment should then be dispositioned in accordance with its importance in achieving that function. • For some complex groups of operator actions (e.g., the response to an anticipated transient without scram (ATWS) in a BWR, or the choice to go to recirculation rather than residual heat removal (RHR) in response to a small LOCA in a PWR), the PRA analysts may have chosen to adopt a bounding approach to the accident scenarios that precludes having to address subsequent actions. This could mean that the equipment associated with those actions might be overlooked in the change process. c. Evaluation Findings Reviewers should verify that information provided and review activities conducted support the following conclusions: • The modeling of human performance is appropriate. • Post-accident recovery of failed components is modeled in a defensible way. Recovery probabilities are realistically quantified. The formulation of the model shows decisionmakers the degree to which the apparently low risk significance of certain items is dependent on credit for recovery of failed components (restoration of component function, as opposed to actuation of a compensating system). 19.2-57 June 2007 • When human actions are proposed as compensatory measures as part of a proposed change, licensee actions to ensure operator performance at the level credited in the risk analysis (e.g., by training, procedures, etc.) are also a part of the change request. A.9 Sequence Quantification a. Areas of Review The staff would not generally anticipate the need to perform a detailed review of the quantification of the change in risk; however, some details of the quantification process should be confirmed. Specifically, reviewers should be confident that the licensee's evaluation process is sufficient to account for the potential effects of the proposed change on modeling simplifications and