Document: NRC Regulatory Guide
Document ID: 3e914c02-41b3-4c0b-9c94-7e4a07215354
Document Type: regulatory_guide
Title: Guidance on Making Changes to Emergency Plans for Nuclear Power Reactors (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1505/ML15054A370.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.219
CFR Part: 
CFR Title: 

Content:
eves will reduce the effectiveness of its emergency plan. Based on its review, the NRC may conclude that the changes (1) do not reduce the effectiveness of the plan, (2) do reduce the effectiveness of the plan but that the NRC continues to have reasonable assurance that adequate protective measures can and will be taken, or (3) unacceptably affect the NRC’s reasonable assurance determination. DG-1324, Page 9 1.2 Role of Conservatism in 10 CFR 50.54(q) Change Evaluations The NRC has always expected, and continues to expect, licensees to make conservative decisions for the operation of nuclear power reactors. Conservative decisionmaking is prudent when the data needed for the decision are unknown or uncertain. Nonetheless, licensees need to remain alert to the possibility of unintended consequences and consider these outcomes in their decisions. The emphasis in emergency preparedness is on prudent risk reduction measures. An overly conservative decision during an emergency response could trigger actions that could place the public at unnecessary risk, thus resulting in a nonconservative situation; “more” is not always “better.” For example, changing a protective action recommendation (PAR) procedure to mandate a default 5-mile, 360-degree evacuation in lieu of considering the actual wind variability at the time of the event may appear conservative because more people would be evacuated. However, the approach could expose individuals upwind of the plant to unnecessary evacuation risks without the benefits of the associated radiation dose avoidance, resulting in a nonconservative situation. 1.3 Role of Probabilistic Risk Assessment Insights in 10 CFR 50.54(q) Change Evaluations The NRC policy statement, “Safety Goals for the Operation of Nuclear Power Plants” (51 FR 30028; August 4, 1986) (Ref. 9), states that emergency preparedness is a “defense-in-depth measure.” Emergency preparedness is carried out as a matter of prudence rather than in response to