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
CFR Part: 
CFR Title: 

Content:
rom proposed changes to plant procedures or changes to operator training included a process to identify these (or similar) activities, and that the licensee evaluated the activities that could be risk contributors. Component Hardware Failure Dependencies: These dependencies, usually referred to as common cause failures (CCFs), cover the failures of usually identical components that may be caused by design, manufacturing, installation, calibration, or operational deficiencies. CCFs are treated quantitatively by common cause failure probabilities or other dependence quantification approaches. Section A.7 of this appendix presents review guidance related to CCFs. Spatial Dependencies: Multiple failures could be caused by events that fail all equipment in a defined space or area. These spatially dependent failures include those caused by internal flooding, fires, seismic events, missiles (e.g., turbine missiles), or any of the other external event initiators. In cases where these events could affect the results of the change evaluation, and where these events are not modeled in the PRA, the dependencies resulting from the unmodeled initiators should be evaluated qualitatively as part of the integrated decisionmaking process. Subsection III.2.2 of this SRP section discusses the required scope of the PRA in more detail. In addition, the change request should include the licensee's consideration of the common influences on component operation such as adverse environment (including excessive temperature, humidity, radiation), inadequate space, inadvertent or spurious sprinkler operation, or routine equipment travel near major components. Reviewers should verify that the change 19.2-49 June 2007 request has used a systematic process to identify potential spatial challenges that could result in multiple failures of SSCs. c. Evaluation Findings Reviewers should verify that information provided and review activities conducted support the following conclusion: Dependencies