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:
ting of Valves in Nuclear Power Plants," of Section XI of the Code. b. Section 3.2, "Structural Requirements," should be supplemented by the following: (I) The interdependence and number of cycles, if applicable, of time, temperatures, pressures, and dynamic loading resulting from plant transients. (2) The time relationship between applied seismic loadings and other concurrent loadings. (3) The frequency response spectra for the operating basis earthquake and the safe shutdown earthquake as well as other potential forcing functions such as those from attached piping, pumps, restraints, or other equipment as applied to valves. (4) The maximum static and dynamic differential pressure (considering all plant operating conditions) that exists across the closure device, including potential water hammer, for which valve assembly operation is to be ensured. c. Section 3.3, "Operational Requirements," should be supplemented by the following: (1) The first paragraph should be supplemented to require that the desired position of the valve assembly in the event of loss of actuator power be specified, e.g., fail open, fail closed, fail as is. (2) In item e of Section 3.3.1, "Operating Condi tions," the phrase "Normal and Abnormal Plant Operation" should be interpreted to include the events covered by plant "Operational Modes (Condition)," 6 and by the Transient and Accident Classification of Chapter 15, "Accident Anal ysis," of Regulatory Guide 1.70. The functional specification should state whether the specific valve assembly safety function applies to events defined in the plant Operational Modes (Condition) or in the Transient and Accident Classi fication. The specification should also indicate whether the actual valve assembly operation (open, close, or regulate fluid flow) occurs during or after the specified event. (3) Instead of item e of 3.3.2, the followingshould be used: "e. motor power and duty requirements, including stall current." (4) Instead of Section 3.3.2.1,