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:
licensee should consider the impact of the proposed licensing basis change on each of the layers of defense: • Robust plant design to survive hazards and minimize challenges that could result should an event occur – The change should not significantly increase the likelihood of initiating events or create new significant initiating events. • Prevention of a severe accident (core damage) should an event occur – The change should not significantly impact the availability and reliability of SSCs that provide the safety functions that prevent plant challenges from progressing to core damage. DG-1285, Page 19 • Containment of the source term should a severe accident occur – The change should not significantly impact the containment function or SSCs that support that function such as containment fan coolers and sprays. • Protection of the public from any releases of radioactive material – The change should not significantly reduce the effectiveness of the emergency preparedness program including the ability to detect and measure releases of radioactivity, notify offsite agencies and the public, and shelter or evacuate the public as necessary. 2. Preserve adequate capability of design features without an overreliance on programmatic activities as compensatory measures. The proposed licensing basis change should not substitute programmatic activities for design features to an extent that significantly reduces the reliability and availability of design features to perform their safety functions without overreliance on programmatic activities. The evaluation of the proposed licensing basis change should demonstrate that the change does not result in an excessive reliance on programmatic activities that are used to compensate for an intended reduction in the capability of engineered safety features. To evaluate this factor, the licensee should first determine whether the proposed licensing basis change necessitates compensatory measures. If not, this should be