Document: NRC Regulatory Guide
Document ID: 22ccfd5e-c5d8-4615-a02c-32369aa9f533
Document Type: regulatory_guide
Title: Acceptability of Probabilistic Risk Assessment Results for Risk-Informed Activities (Rev. 3)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1930/ML19308B636.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.200
CFR Part: 
CFR Title: 

Content:
venience in the knowledge that a more detailed model would produce different results. base PRA The base PRA is the PRA from which results or insights are derived or that is modified and/or manipulated to support a risk-informed NRC regulatory activity. In some cases, such as applications related to Title 10 of the Code of Federal Regulations Section 50.69 (Ref. 13), the PRA used in the application may be the base PRA. The base PRA provides a quantitative assessment of the identified risk of the as-built and as-operated plant in terms of scenarios that result in undesired consequences (e.g., core damage or a large early release) and their frequencies and is comprised of specific technical elements in performing the quantification. The base PRA serves as the foundational representation of the as-built and as-operated plant necessary to support an application. consensus method/model In the context of risk-informed regulatory decisions, a consensus method or model approach is one that the NRC has used or accepted for the specific risk- informed application for which it is proposed. A consensus method or model may also have a publicly available published basis and may have been peer reviewed and widely adopted by an appropriate stakeholder group. conservative Relates to the use of information (e.g., assumptions) such that the assessed outcome is meant to be less realistic in a cautious manner as compared to the expected outcome. current good practice (or state of practice) Practices that are widely accepted by and implemented throughout the commercial nuclear power industry; have been shown to be technically acceptable in well-documented analyses or engineering assessments that are publicly available; and are accepted by the NRC. demonstrably conservative Relates to the use of information (e.g., assumptions) that provides high confidence that the assessed outcome is as conservative as it is portrayed to be. DG-1362, Page 55 key assumption An assumption is considered to