Document: 10 CFR Part 50
Document ID: e5e51d71-6583-44f4-85e4-1d59c4ed1c3c
Document Type: cfr
Title: Combustible gas control for nuclear power reactors.
Source: 10 CFR Part 50
Source URL: https://www.ecfr.gov/current/title-10/part-50/section-50.44
Revision Date: 
Chapter: 
Section ID: 50.44
CFR Part: 50
CFR Title: 10

Content:
n approvals, design certifications, combined licenses or manufacturing licenses under part 52 of this chapter , any of which are issued after October 16, 2003. ( 1 ) Mixed atmosphere. All containments must have a capability for ensuring a mixed atmosphere during design-basis and significant beyond design-basis accidents. ( 2 ) Combustible gas control. All containments must have an inerted atmosphere, or must limit hydrogen concentrations in containment during and following an accident that releases an equivalent amount of hydrogen as would be generated from a 100 percent fuel clad-coolant reaction, uniformly distributed, to less than 10 percent (by volume) and maintain containment structural integrity and appropriate accident mitigating features. ( 3 ) Equipment Survivability. Containments that do not rely upon an inerted atmosphere to control combustible gases must be able to establish and maintain safe shutdown and containment structural integrity with systems and components capable of performing their functions during and after exposure to the environmental conditions created by the burning of hydrogen. Environmental conditions caused by local detonations of hydrogen must also be included, unless such detonations can be shown unlikely to occur. The amount of hydrogen to be considered must be equivalent to that generated from a fuel clad-coolant reaction involving 100 percent of the fuel cladding surrounding the active fuel region. ( 4 ) Monitoring. ( i ) Equipment must be provided for monitoring oxygen in containments that use an inerted atmosphere for combustible gas control. Equipment for monitoring oxygen must be functional, reliable, and capable of continuously measuring the concentration of oxygen in the containment atmosphere following a significant beyond design-basis accident for combustible gas control and accident management, including emergency planning. ( ii ) Equipment must be provided for monitoring hydrogen in the containment. Equipment for