Document: NRC Regulatory Guide
Document ID: 25a5daff-c390-423e-a736-7744b82624bb
Document Type: regulatory_guide
Title: Preoperational Testing of Instrument Air Systems
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1306/ML13064A110.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.80
CFR Part: 
CFR Title: 

Content:
an improperly set dryer refrigerant expansion valve. In other cases, the freezing was caused by unusually cold weather. This guide should also be considered applicable to instrument systems utilizing other gases such as nitrogen. The applicant is responsible for the development of a suitable preoperational test program for the instrument air system, the preparation of adequate procedures for carrying out the program, the proper conduct of the preoperational tests, and the validity of the test results. A significant consideration related to the performance of the instrument air system is how the valves controlled by the system will respond to the loss of instrument air supply. Valves are designed to respond in a given manner, i.e., fail open, fail closed, or fail as is, if the instrument air supply is lost. Verification of design response to a loss-of-instrument-air accident is an essential part of testing at the preoperational stage, at which time it can be accomplished with a minimum risk to power plant equipment and personnel. The test will also provide a means for determining the adequacy of operating and emergency procedures for coping with a loss of instrument air supply. C. REGULATORY POSITION As part of the initial preoperational testing program, and also after major modifications or repairs to a facility, the instrument air system should be tested as. described below to verify that all components function properly and that the systems respond as designed to a loss-of-instrument-air-supply accident. 1. The test program for the instrument air system and its associated equipment should include applicable checks, verifications, tests, and reports outlined in Regulatory Guide 1.68, "Preoperational and Initial Startup Test Programs for Water-Cooled Power Reactors" as a prerequisite to or in conjunction with the tests of this regulatory guide. 2. Compressors, aftercoolers, oil separator units, and air receivers should be tested to verify proper operation according