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:
ormed during the plant history for operating plants • Reflect the success criteria for the systems to mitigate each identified accident sequence • Capture impact of dependencies, including support systems and abnormal environmental impacts • Include both active and passive components and failure modes that impact the function of the system • Include common-cause failures, human errors, unavailability resulting from test and maintenance, etc. DG-1362, Page 17 Table 2. Summary of Technical Characteristics and Attributes of a Level 1, Internal Events PRA for the At-Power Operating Mode Element Technical Characteristics and Attributes Parameter Estimation Analysis • Estimation of parameters associated with initiating event, basic event probability models, recovery actions, and unavailability events using plant-specific and generic data as applicable • Estimation is consistent with component boundaries • Estimation includes a characterization of the uncertainty Human Reliability Analysis • Identification and definition of the HFEs that would result in initiating events or pre- and post-accident HFEs that would impact the mitigation of initiating events • Quantification of the associated human error probabilities (HEPs) considering scenario (where applicable) and plant-specific factors (as available) and including appropriate dependencies (both pre- and post-accident) • NUREG-1792 (Ref. 41) and NUREG-1842 (Ref. 42) provide good practices for meeting the above characteristics and attributes Quantification • Estimation of the CDF for modeled sequences that are not screened as a result of truncation, given as a mean value • Estimation of the accident sequence CDFs for each initiating event group • Truncation values set relative to the total plant CDF such that the CDF is stable with respect to further reduction in the truncation value Technical Elements for Level 2, Internal Events PRA This section identifies the technical elements for a Level 2,