Document: NUREG-0800
Document ID: faf774de-7226-41f8-ba11-7cf612907af6
Document Type: srp
Title: GASEOUS WASTE MANAGEMENT SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1306/ML13065A119.pdf
Revision Date: 2023-06
Chapter: 11
Section ID: 11.3
CFR Part: 
CFR Title: 

Content:
g system should minimize sample losses and distortion of the sample's chemical and physical properties. 9. If the potential for explosive mixtures of hydrogen and oxygen exists, the GRS portion of the GWMS should either be designed to withstand the effects of a hydrogen explosion or be provided with dual gas analyzers with automatic control functions to preclude the formation or buildup of explosive gas mixtures. The GRS is normally the only portion of the system that is vulnerable to potential hydrogen explosion. A. For a system designed to withstand the effects of a hydrogen explosion, the design pressure of the system should be approximately 20 times the operating absolute pressure (including the intermediate stage condenser for BWR offgas systems). B. Small allowances should be made to conform to standard design pressures for off-the-shelf components (e.g., if the system operating pressure is nominally 103 kPa (15 psia) but could approach 138 kPa (20 psia) by design, piping could be designed to 2413 kPa (350 psia), since the next higher standard pressure rating is 4137 kPa (600 psia)). C. The process gas stream should be analyzed for potentially explosive gas mixtures and annunciated both locally and in the control room. 11.3-14 Draft Revision 4 – August 2014 D. For systems not designed to withstand a hydrogen explosion, dual gas analyzers with automatic control functions should preclude the formation or buildup of explosive hydrogen/oxygen mixtures. In this context, “dual gas analyzers” is defined as two independent gas analyzers continuously operating and providing two independent measurements verifying that hydrogen and/or oxygen are not present in potentially explosive concentrations. Gas analyzers should annunciate alarms both locally and in the control room. Analyzer “high alarm” setpoints should be set at approximately 2 percent and “high-high alarm” setpoints should be set at a maximum of 4 percent hydrogen or oxygen. Control features to