Document: NUREG-0800
Document ID: 936f16a2-5593-4498-8533-ddca55910376
Document Type: srp
Title: COMBUSTIBLE GAS CONTROL IN CONTAINMENT
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340704.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.2.5
CFR Part: 
CFR Title: 

Content:
rovide systems to control the concentration of hydrogen or oxygen in the containment atmosphere following postulated accidents, the fission product decay energy used in the calculation of hydrogen and oxygen production from radiolysis of the emergency core cooling water and sump water is acceptable if it is equal to or more conservative than the decay energy model given in Branch Technical Position ASB 9-2 in SRP Section 9.2.5. 3. In meeting the requirements of 10 CFR Part 50, §§ 50.44 and 50.46 to provide the capability for insuring a mixed atmosphere in the containment, and of GDC 41 to provide systems as necessary to assure that containment integrity is maintained, a system should be provided to mix the combustible gases within the containment. The functional design of this system will depend on the type of containment. This system may consist of a fan, a fan cooler, or containment spray. An analysis should be presented which shows that excessive stratification of combustible gases will not occur within the containment or within a containment subcompartment. For containments which rely on convective mixing in conjunction with system operation to mix the combustible gases, the containment internal structures must have design features which promote the free circulation of the atmosphere. An analysis of the effectiveness of these features for convective mixing should be presented. This analysis is acceptable if it can be shown that combustible gases will not accumulate within a compartment or cubicle to form an com- bustible mixture. 6.2.5-4 Rev. 2 - July 1981 4. In meeting thb requirements of 10 CFR Part 50, §§ 50.44 and 50.46 and GDC 41 regarding the functional capability of the combustible gas control systems to assure that containment integrity is maintained, the systems provided to reduce the concentration of hydrogen or oxygen in the contain- ment will be accepted, from a functional standpoint, if analyses indicate that a single system train is capable of