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:
current as-designed [added], as-built and as-operated plant. 7. The standard is a living document. Consequently, it should not impede research. It is structured so that, when improvements in the state of knowledge occur, the standard can easily be updated. Principle 3 recognizes that the technical requirements of a PRA can be, and generally are, performed to different “capabilities.” In developing the various models in the PRA, the different capabilities are distinguished by three attributes, determined by the degree to which the following criteria are met: • The scope and level of detail that reflects the plant design, operation, and maintenance. DG-1362, Page 40 • The use of plant-specific information versus generic information to represent the as-designed, as- built, and as-operated plant. • The degree of realism that is incorporated into the base PRA model to reflect the expected response of the plant. It is recognized that a PRA may not satisfy each technical requirement to the same degree (i.e., capability category as used in an ASME/ANS PRA standard); that is, the capability category achieved for the different technical requirements may vary. This variation can range from (1) the minimum needed to meet the characteristics and attributes for each technical element to (2) the minimum to meet current good practice (i.e., state-of-practice) for each technical element. Further, which capability category is needed to be met for each technical requirement is dependent on the specific application. In general, the staff anticipates that current good practice (i.e., Capability Category II of an ASME/ANS PRA standard) is the level of detail that is acceptable for the majority of applications. However, for some applications, Capability Category I may be acceptable for some requirements. There may be other situations where the state-of-practice is not acceptable for a specific application. For example, it is not state-of-practice to include pipe failures in a