Document: NUREG-0800
Document ID: 65414bbc-012c-477d-8c25-466f94c1671f
Document Type: srp
Title: GASEOUS WASTE MANAGEMENT SYSTEMS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052350105.pdf
Revision Date: 2023-06
Chapter: 11
Section ID: 11.3
CFR Part: 
CFR Title: 

Content:
ide 1.140 are used for design purposes, they should be supported by test data under operating or simulated operating conditions (temperature, pressure, humidity, expected iodine concen- 'trations, 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 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. 11.3-4 Rev. 2 - July 1981 a. For a system designed to withstand the effects of a hydrogen explosion, the design pressure of the system should be approxi- mately 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 15 psia but could approach 20 psia by design, piping could be designed to 350 psia, since the next higher standard pressure rating is 600 psia. The process gas stream should be analyzed for potentiallW- 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 inde- pendent measurements verifying that hydrogen and/or oxygen are not present in potentially-explosive concentrations) with automatic control functions are required to preclude the for- mation 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 potential for