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:
other particulate matter that could degrade the systems operation or capability. d. For power cycle waste offgas systems relying on activated carbon delay tanks or beds, the above environmental design criteria are deemed applicable, but should be evaluated and applied taking into consideration the system’s specific design features. 3. System Design Criteria Normal atmospheric cleanup systems should be designed in accordance with ASME AG-1b-2009 as modified and supplemented by the following: a. Normal atmosphere cleanup systems need not be redundant or designed to seismic Category I requirements, but they should consist of at least the following components: (1) high-efficiency particulate air (HEPA) filters upstream of adsorbers, (2) iodine adsorbers (typically impregnated activated carbon), if iodine removal from the airstream is anticipated, (3) fans, (4) interspersed ducts, dampers, and instrumentation, (5) prefilters upstream of HEPA filters, if needed to reduce particulate loading of the HEPA filters and achieve an acceptable service life, (6) postfilters downstream of adsorbers, if needed to retain carbon fines, and (7) heating elements or cooling coils, or both, if necessary to control humidity before filtration. b. The volumetric airflow rate of a single filtration unit should be limited to 850 cubic meters (30,000 cubic feet) per minute unless reliable in-place testing can be assured. If a higher flow capacity is needed, consider a system design with multiple, parallel units. c. Normal atmosphere cleanup systems should be provided with instrumentation recommended in Section IA of ASME AG-1b-2009 for monitoring and alarming pertinent airflow rates and pressure drops. d. Normal atmosphere cleanup systems design should limit personnel radiation exposure by incorporation of features that facilitate inspection, testing, and maintenance consistent with the guidance of Regulatory Guide 8.8, “Information Relevant to Ensuring that Occupational Radiation Exposures