Document: NRC Regulatory Guide
Document ID: dff52070-b179-4367-bf66-5d1107c54315
Document Type: regulatory_guide
Title: Design, Inspection, and Testing Criteria for Air Filtration and Adsorption Units of Normal Atmosphere Cleanup Systems in Light-Water-Cooled Nuclear Power Plants + HISTORY – HISTORY 06/2012 – DG-1280 , Proposed Revision 3 10/2000 – DG-1103 , Proposed Revision 2 (Rev. 3)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1127/ML11273A057.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.140
CFR Part: 
CFR Title: 

Content:
nclude low-flow air or inert gas bleed, cooling coils, cleanup unit isolation, or water sprays. (2) If a water-based fire suppression or prevention (cooling) system is installed in a normal atmosphere cleanup system housing, it should be designed for manual actuation unless a reasonable possibility exists that iodine desorption and adsorbent autoignition could occur in the housing. If autoignition is a reasonable possibility, the fire suppression system should have both manual and automatic actuation. The fire suppression system should use open spray nozzles of sufficient size, number, and location to provide complete coverage over the entire surface of the combustible filter/adsorber media. The fire system should be hard piped and supplied with a reliable source of water of adequate pressure and flow. Location of the water supply manual actuation device should be remote from the cleanup system housing and consistent with the guidance of Regulatory Guide 8.8 (Ref. 10). Reliable mechanical or electrical detection devices sensing temperature, smoke, carbon monoxide, or other indications of fire ignition should be included in the system for manual and automatic actuation methods. Monitoring indicators for these detector outputs should be remote from the system housings and consistent with the guidance of Regulatory Guide 8.8 and support the manual actuation capability. Cross-zoning of detectors may be used for automatic actuation. (3) For portions of atmospheric clean up systems and power cycle off gas systems (such as filter housings, delay tanks or beds, and low-points in ductwork), the design should consider features to collect and drain accumulated water from various sources. The presence and accumulation of water within portions of these systems may be attributed to condensation and from water-based fire suppression systems, when triggered. The design should provide the means to collect and route water to the appropriate radioactive waste management system given