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:
nce provided in Subsection 11.2, "Pump and Valve Operability Assurance Program," of Section 3.9.3 of the Standard Review Plan. A proposed revision to the Standard Review Plan will also affect previous definitions of the term "active." The staff plans to use the following proposed definition: Active valves - valves that, during or following postulated accidents, must perform a mechanical motion in order to shut down the plant, main tain the plant in a safe shutdown condition, or mitigate the consequences of a postulated event. Safety and relief valves provided in accordance with the requirements of ASME Code Section III are specifically included. It appears that component standards usually concentrate on accomplishing a single goal such as providing pressure boundary integrity even though it may be necessary to address a relatively broad subject matter that could include materials properties, design rules, testing rules, and certifica tion requirements in order to meet the desired goal. An example of this approach is Section III of the Code. Simi larly, Section XI, "Rules for Inservice Inspection of Nuclear Power Plant Components," of the Code provides, as one of several goals, rules for inservice testing of valve assemblies, while ANSI N278.1-1975 is directed toward operabiliiy of valve assemblies in systems important to safety. It is there fore evident that the complete spectrum from construction 4 through operability to inservice testing of a valve assembly is covered by separate codes and standards even though there is a necessary relationship among them. Hence, the staff believes that (1) there is a need for a set of comprehen sive requirements to provide the detailed documentation that serves as the basis for construction, assurance of operability. inservice testing, and applicability of and relationship among the separate standards and (2) there should be both technical compatibility and consistent 4As defined in Section III of the Code, "construction" is an