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:
s, the method described in this guide will be used in the evaluation of (1) construction permit applications, (2) standard reference system preliminary design applications (PDA) or Type-2 final design applications (FDA-2), and (3) licenses to manufacture that are docketed after July 1, 1981, except those portions of a construction permit application that. a. Reference an approved standcrd reference system preliminary or final design (PDA or FDA), or an application for approval of such design. b, Reference an approved standard duplicate plant preliminary or final design (PDDA or FDDA). c. Reference parts of a base plant design qualified and approved for replication. d. Reference a plant design approved or under review for approval for manufacture under a Manufacturing License. This guide will also be used as the basis for evaluating new systems important to safety and replacement valve units ordered after July 1, 198 1, for plants that are operat ing or under construction. 1.148-4 VALUE/IMPACT STATEMENT Background Valve assemblies (i.e., pressure-retaining portions of the valve, its internals, its actuator, and attached functional accessories) installed in nuclear power plants have experi enced numerous malfunctions in the past. Licensee Event Reports (LERs) show that these malfunctions occur at a frequency that is cause for concern. Approximately 3440 LERs were received over the period from 1969 to July 1, 1980. The origin of valve assembly malfunctions varies widely; however, one of the major problems that was recognized at the valve operability meeting held with industry on November 20, 1972, is that equipment specifica tions are deficient in defining the application and the environmental and loading conditions for valve assemblies in nuclear power plants. As a result of the 1972 meeting, effort on developing valve operability standards was initiated under the auspices of the American National Standards Institute Committee N45. Subsequently, this standards