Document: NUREG-0800
Document ID: fe8ec6c2-e960-404c-854f-55c77bde1672
Document Type: srp
Title: NUREG-0800
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML2400/ML24005A077.pdf
Revision Date: 2024-05
Chapter: 7
Section ID: 7
CFR Part: 
CFR Title: 

Content:
on-Cause Failures Point 3 of SRM-SECY-22-0076 states that applicants must demonstrate the adequacy of any design techniques, prevention measures, or mitigation measures, other than diversity, that are credited in the assessment. Point 3 also states that the level of technical justification demonstrating the adequacy of these techniques or measures, other than diversity, to address CCFs must be commensurate with the risk significance of each CCF. Point 3 concludes by stating that, if a postulated CCF is risk significant and the assessment does not demonstrate the adequacy of other design techniques, prevention measures, or mitigation measures, then a BTP 7-19-34 Revision 9 — May 2024 diverse means must be provided. For risk-significant CCFs, the level of technical justification needed can be determined by mapping the increase in risk from the CCF to the acceptance guidelines in RG 1.174. For example, a higher level of technical justification is needed for CCFs that fall in Region I than for those that fall in Region II of figures 4 or 5 in RG 1.174. The most recent plant-specific CDF and LERF should be used for the mapping. Acceptance Criteria for Determining Appropriate Means to Address Common-Cause Failures If a CCF is not risk significant (i.e., the increase in risk from the CCF falls in Region III of figures 4 and 5 of RG 1.174), then the reviewer should conclude that standard design and verification and validation processes are sufficient to address the CCF. If a CCF is risk significant and the application meets the acceptance criteria below, with a level of technical justification commensurate with the risk significance of the CCF (as characterized by mapping its increase in risk to the regions in RG 1.174), then the reviewer should conclude that appropriate means to address the CCF have been applied: a. The application identifies the CCF vulnerabilities or causes. If these CCF vulnerabilities or causes are identified using a hazard analysis technique, then