Document: NRC Regulatory Guide
Document ID: 8a2332d3-66ca-40af-84e1-507db8b26559
Document Type: regulatory_guide
Title: TRIAL - Acceptability of Probabilistic Risk Assessment Results for Non-Light Water Reactor Risk-Informed Activities
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2123/ML21235A008.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.247
CFR Part: 
CFR Title: 

Content:
emonstrate that the PRA has been developed and used in a technically acceptable manner, including the appropriateness of the assumptions and approximations used in developing the PRA. • Identify the application-specific acceptance criteria and demonstrate that they have been met. The following sections provide more detailed guidance on each of these aspects of the staff assessment. PRA acceptability for a given risk-informed activity is determined in the context of the staff positions in this RG and relevant application-specific regulatory guidance. C.3.1 Probabilistic Risk Assessment Scope, Level of Detail, and Degree of Plant Representation The scope of a PRA needed to support an application will depend on the application-specific regulatory requirements, and the acceptability of the scope will be measured in terms of whether the applicant or holder of a license, certification, or permit meets those requirements. Application-specific guidance documents are expected to provide direction on meeting such requirements. For plants in the preoperational stages of the plant life cycle, the PRA and its results used to support an application are expected to reflect the as-designed, as-to-be-built, or as-to-be-operated plant. For operating plants, the PRA should reflect the as-built and as-operated plant. When used for risk-informed decision-making, the PRA should always reflect the best available information for the plant. For most applications, an applicant or holder of a license, certification, or permit should address all radiological sources, all hazards, all POSs, and all levels of analysis, as discussed in Regulatory RG 1.247, Page 61 Position C.1.1 of this RG. The staff will assess the appropriateness of the justification for any deviations from this scope. C.3.2 Development and Use of an Acceptable Probabilistic Risk Assessment The staff positions in Regulatory Positions C.1 through C.1.4 represent the minimum capability the staff has determined that a PRA should