Document: NUREG-0800
Document ID: 6cd85972-0d5c-413b-9587-fbbfd5521c9f
Document Type: srp
Title: COMPRESSED AIR SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070525.pdf
Revision Date: 2023-06
Chapter: 9
Section ID: 9.3.1
CFR Part: 
CFR Title: 

Content:
ety-related components and systems and subsystems that provide compressed air to non-safety-related components and systems. For the purposes of these technical rationales, those portions of compressed air systems that provide control air to safety-related components and systems are referred to as the instrumentation and control air system (ICAS).61 1. GDC-1 requires that structures, systems, and components important to safety be designed, fabricated, erected, and tested to quality standards commensurate with the importance of the safety functions to be performed. The ICAS provides compressed air or nitrogen required to actuate or control equipment that perform safety-related functions during normal operations, transients, or accidents. Generic Issue 43, "Reliability of Air Systems", identified concerns regarding the reliability of safety-related equipment actuated or controlled by compressed air. As indicated in NUREG-1275 (Reference 7) and Generic Letter 88-14 (Reference 8) related to this generic issue, contamination (e.g., oil, particulate, water, etc.) of compressed air was identified as significant contributor to unreliability in safety-related equipment controlled or actuated by compressed air. In some plant designs, the ICAS or equipment supplied by ICAS may be supplied from backup compressed air sources outside the scope of the ICAS under certain operating conditions. In these cases there is the potential for a contaminated compressed air source to adversely affect the reliability of the ICAS or equipment supplied by the ICAS. Regulatory Guide 1.68.3 recognizes this potential and Position C.9 provides guidance that preoperational testing should verify that equipment designed to be supplied by the instrument and control air system is not being supplied by other compressed air supplies that may have less restrictive air quality requirements. ANSI/ISA-S7.3-R1981 provides air quality criteria that, if followed for the ICAS and backup compressed air sources, will