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:
he reviewer should conclude that the application provides sufficient information on determining the risk significance of the CCF: a. If the increase in risk from the CCF is calculated using a bounding sensitivity analysis, the bounding sensitivity analysis presumes that the CCF occurs (i.e., that the probability of failure of the surrogate events is 1) and the application describes the baseline risk used to determine the increase in risk (e.g., the basis for the nominal failure probability for the CCF used in the baseline model is 0, meaning the CCF does not occur in the baseline model). b. If the increase in risk from the CCF is calculated using a sensitivity analysis that assumes a conservative value less than 1 for the probability of the CCF, the following conditions are met: i. The application includes a technical basis that demonstrates that an adequate level of defense in depth is provided for the conservative probability less than 1. ii. The application assesses the impact of this assumption on PRA uncertainty and determines whether it is a key assumption. The application also assesses the impact of the assumption on the key principles of risk-informed decision-making, including defense in depth. c. The risk quantification accounts for any dependencies introduced by the CCF, including the ability of operators to perform manual actions affected by the CCF. The following acceptance criteria, which are to be used in conjunction with the information in the application related to the principles of risk-informed decision-making in RG 1.174, apply for CCFs determined to be not risk significant: a. The increase in CDF from the CCF is less than 1x10-6/year. b. The increase in LERF from the CCF is less than 1x10-7/year. 3.4.4 Determining Appropriate Means to Address Common-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