Document: NRC Regulatory Guide
Document ID: 60ac4a53-3f72-4e92-9ad2-39c736cf2135
Document Type: regulatory_guide
Title: Functional Specification for Active Valve Assemblies in Systems Important to Safety in Nuclear Power Plants
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0037/ML003739979.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.148
CFR Part: 
CFR Title: 

Content:
ide 1.70, Revision 3, "Standard Format and Content of Safety Analysis Reports for Nuclear Power Plants." Additionally, all applicants are cognizant of NRC staff positions on valve assembly operability as identified in Regulatory Guide 1.48, "Design Limits and Loading Combinations for Seismic Category I Fluid System Components," and Sections 3.9.3 and 3.9.6 of the Standard Review Plan. It is therefore evident that the proposed guide does not introduce a new or additional safety subject. However, ANSI N278.1-1975 was published approxi mately 5 years ago, and there are indications that it has not been extensively used. It appears that the question of which valve assemblies should meet the standard determines the potential impact. Since the staff recommends initial applica tion of the standard to active valve assemblies, which are addressed in Section 3.9.3.2 of Regulatory Guide 1.70, the impact should be restricted to situations where specific deficiencies exist in individual applicant equipment specifica tions. A thorough process to identify additional active valve assemblies in systems important to safety that should have functional specifications in accordance with ANSI N278.1 1975 would require extensive staff time because differing plant system characteristics make it difficult to establish generic groups. The term "safety-related" affects this process because Regulatory Guide 1.26, "Quality Group Classifications and Standards for Water-, Steam-, and Radioactive-Waste-Containing Components of Nuclear Power Plants," refers to Quality Groups A, B, C, and D for safety-related components. However, it may not be desirable or necessary to have all the detail required in the standard for all valve assemblies that may be classified in accordance with Regulatory Guide 1.26. Another potential area of concern relates primarily to purchasing valve assemblies by a licensee or its agent. Application of the specification requirements of this standard to preselected valve