Document: NRC Regulatory Guide
Document ID: 2459a562-8984-421c-8058-d096dbb9617c
Document Type: regulatory_guide
Title: Guidelines for Categorizing Structures, Systems, and Components in Nuclear Power Plants According to Their Safety Significance
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0314/ML031430373.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.201
CFR Part: 
CFR Title: 

Content:
the categorization process described in 10 CFR 50.69 and in NEI 00-04 is primarily based on system/structure functions, the categorization process must be implemented on a system/structure-basis; not selected components within a system. This is supported by the fact that system boundaries are to be defined under the “System Engineering Assessment” step of the categorization process outlined in Section 2. 4. Section 2 In this section and throughout NEI 00-04, reference is often made to a licensee’s “PRA.” This phrase is commonly used by industry when referring strictly to a licensee’s internal events Level I PRA. The NRC staff interprets the intent of this phrase in NEI 00-04, when not explicitly (or by context) limited to a specific analysis, to refer to the spectrum of analyses covering the range of initiating events (e.g., internal events and external events), analysis types (e.g., PRA, margins- type analyses, simplified risk analyses, and hazard screening assessments), and operating modes (i.e., full power and low power/shutdown). Although it is clear from the text of Section 2, NEI should clarify the intent of Figure 2-1 that the “Detailed Engineering Review of HSS Components” is an optional task and is not an essential or required part of the risk-informed categorization process. (Note: NEI 00-04 uses the terms high safety-significant and low safety-significant; these correspond to the terms safety-significant and low safety-significant, as used in the proposed rule). 3 5. Section 3.2 The NRC staff is currently preparing a Regulatory Guide and associated Standard Review Plan (SRP) chapter to address the issue of PRA quality. These documents will address the use of NEI 00-02, which when finalized, is expected to contain a licensee self-assessment process that complements the peer review criteria with those of the American Society of Mechanical Engineers (ASME) PRA standard not addressed in NEI 00-02. The NRC staff expects the final version of