Document: NRC Regulatory Guide
Document ID: 82659041-98b0-4721-b25d-c4fb2ea394d0
Document Type: regulatory_guide
Title: An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis (Rev. 3)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1635/ML16358A153.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.174
CFR Part: 
CFR Title: 

Content:
ld demonstrate that the change does not: • Create a significant increase in the likelihood or consequence of an event that simultaneously challenges multiple barriers. • Introduce a new event that would simultaneously impact multiple barriers. To evaluate this factor, the licensee should consider achieving the following objectives to ensure that the proposed licensing basis change maintains consistency with the defense-in- depth philosophy: • The change does not result in a significant increase in the frequency of existing challenges to the integrity of the barriers. • The proposal does not significantly increase the failure probability of any individual barrier. • The proposal does not introduce new or additional failure dependencies among barriers that significantly increase the likelihood of failure compared to the existing conditions. DG-1285, Page 22 6. Preserve sufficient defense against human errors. The proposed licensing basis change should not significantly increase the potential for or create new human errors that might adversely impact one or more layers of defense. The evaluation of the proposed licensing basis change should demonstrate that the change does not adversely affect the ability of plant staff to perform actions. To evaluate this factor, the licensee should determine whether the proposed licensing basis change would: • Create new human actions that are important to preserving any of the layers of defense. • Place a significantly increased mental or physical demand on individuals responding to events. • Significantly increase the probability of existing human errors. Consideration of human actions should include errors for operators, maintenance personnel, and other plant staff. 7. Continue to meet the intent of the plant’s design criteria. The proposed licensing basis change should not affect meeting the intent of the plant’s design criteria referenced in the licensing basis. The evaluation of the proposed licensing basis