Document: NUREG-0800
Document ID: 545a669a-51a1-4b1f-9d90-78ee08ca0845
Document Type: srp
Title: COMBUSTIBLE GAS CONTROL IN CONTAINMENT
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070463.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.2.5
CFR Part: 
CFR Title: 

Content:
ustible gas control systems to assureensure that containment integrity is maintained, the systems provided to reduce the concentration of hydrogen or oxygen in the containment will be accepted, from a functional standpoint, if analyses indicate that a single system train is capable of maintaining the concentration of hydrogen or oxygen below the concentration limits specified in Table 1 of Regulatory Guide 1.7. Acceptance of the functional capability of the systems is based on confirmatory analyses performed by CSBSCSB using the COGAP code as described in the Appendix A of this SRP section and the system operating parameters presented in the safety analysis report. The proposed operation of the combustible gas control equipment, excluding containment atmosphere dilution (CAD) systems, is acceptable if there is an appropriate margin, e.g., on the order of 0.5 v/o, between the limiting hydrogen concentration limit and the hydrogen concentration at which the equipment would be actuated. The proposed operation of CAD systems will be acceptable if there is a margin of 1 v/o between the limiting hydrogen or oxygen concentration limit, depending on which gas is being controlled, and the concentration at which the system would be actuated. This additional margin is needed to allow time for the CAD system to become operational. Repressurization of the containment should be limited to less than 50% of the containment design pressure. 5. In meeting the requirements of 10 CFR Part 50, §§ 50.34, 50.44 and 50.46 and GDC 41 regarding the functional capability of the combustible gas control systems to assureensure that containment integrity is maintained, system components such as ductwork and equipment housings, e.g., for fans, fan coolers, filters, and recombiners, should be capable of withstanding all related environmental conditions imposed on them, including external transient differential pressures and internal pressure surges without loss of function. A description of the