Document: NUREG-0800
Document ID: c0c5657a-82df-46c2-8cb5-fad0fd37fb58
Document Type: srp
Title: GASEOUS WASTE MANAGEMENT SYSTEMS1
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070610.pdf
Revision Date: 2023-06
Chapter: 11
Section ID: 11.3
CFR Part: 
CFR Title: 

Content:
d iodine concentrations, and flow rate). The effects of aging and poisoning by airborne contaminants should also be supported by test data. 6. If the potential for an explosive mixture of hydrogen and oxygen exists, the GRS portion of the gaseous waste management systems 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 mixtures. The GRS is normally the only portion of the system that is vulnerable to potential hydrogen explosion.43 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). Small allowances should be made to conform to standard design pressures for off-the-shelf components; i.e., if the system operating pressure is nominally 103 kPa (15 psia) but could approach 138 kPa (20 psia) by 44 45 design, piping could be designed to 2413 kPa (350 psia), , since the next 46 higher standard pressure rating is 4137 kPa (600 psia).47 The process gas stream should be analyzed for potentially explosive mixtures and annunciated both locally and in the control room. b. For systems not designed to withstand a hydrogen explosion, dual gas analyzers (with dual being defined as two independent gas analyzers continuously operating and providing two independent measurements 11.3-7 DRAFT Rev. 3 - April 1996 verifying that hydrogen and/or oxygen are not present in potentially explosive concentrations) with automatic control functions are required to preclude the formation or buildup of explosive hydrogen/ oxygen mixtures. Gas analyzers should annunciate alarms both locally and in the control room. "high alarm" should be set approximately 2% and "High-high alarm" should be set at a maximum of 4% hydrogen or oxygen. Control features to reduce