Key Issues
Nuclear Power Plant Fire Protection
<< Previous
Creation of Regulations
The NRC issued fire protection guidance to utilities shortly after the Browns Ferry fire and, over the next several years, developed a regulation with detailed requirements related to fire prevention and detection, fire brigade training, and other areas of fire protection. The NRC codified these requirements in 1981 in 10 CFR 50.48 and 10 CFR 50, Appendix R.
These regulations, still in force, require plants to protect critical structures and reactor equipment “important to safe shutdown” in the unlikely event of a fire. Utilities use various devices—fire detectors, heat sensors, remote cameras, automatic sprinklers and others—to aid them in this mission.
The regulation also requires plants to protect at least one set of systems needed to shut down the plant safely—one of the major lessons of the Browns Ferry fire. Plants now must separate certain systems and components by at least 20 feet or provide a comparable level of protection.
A utility can meet the requirement with either a fire barrier rated for one hour, plus automatic suppression and detection equipment, or with a three-hour-rated barrier.
These fire-rating requirements are somewhat arbitrary. They apply equally to all areas where fire barriers are in place, regardless of the actual fire hazard. In practice, however, the NRC has granted exemptions for plant areas where the fire hazard is low and where features of the plant make it extremely difficult to install a fire barrier. In addition, the NRC has recently added a voluntary option to 10 CFR 50.48 that allows performance-based approaches that model expected fire sizes and effects.
The inaccessibility of some plant areas posed problems for firefighters battling the Browns Ferry fire. Some burning cable trays, for example, were 30 feet above the floor and difficult to reach with fire hoses. The NRC solution: built-in, automatic fire suppression systems.
False actuation of sprinkler systems, however, could damage electrical equipment. Some companies have asked the NRC to use manual systems in areas with electrical equipment. The NRC has granted some requests.
Creation of Regulations
The NRC issued fire protection guidance to utilities shortly after the Browns Ferry fire and, over the next several years, developed a regulation with detailed requirements related to fire prevention and detection, fire brigade training, and other areas of fire protection. The NRC codified these requirements in 1981 in 10 CFR 50.48 and 10 CFR 50, Appendix R.
These regulations, still in force, require plants to protect critical structures and reactor equipment “important to safe shutdown” in the unlikely event of a fire. Utilities use various devices—fire detectors, heat sensors, remote cameras, automatic sprinklers and others—to aid them in this mission.
The regulation also requires plants to protect at least one set of systems needed to shut down the plant safely—one of the major lessons of the Browns Ferry fire. Plants now must separate certain systems and components by at least 20 feet or provide a comparable level of protection.
A utility can meet the requirement with either a fire barrier rated for one hour, plus automatic suppression and detection equipment, or with a three-hour-rated barrier.
These fire-rating requirements are somewhat arbitrary. They apply equally to all areas where fire barriers are in place, regardless of the actual fire hazard. In practice, however, the NRC has granted exemptions for plant areas where the fire hazard is low and where features of the plant make it extremely difficult to install a fire barrier. In addition, the NRC has recently added a voluntary option to 10 CFR 50.48 that allows performance-based approaches that model expected fire sizes and effects.
The inaccessibility of some plant areas posed problems for firefighters battling the Browns Ferry fire. Some burning cable trays, for example, were 30 feet above the floor and difficult to reach with fire hoses. The NRC solution: built-in, automatic fire suppression systems.
False actuation of sprinkler systems, however, could damage electrical equipment. Some companies have asked the NRC to use manual systems in areas with electrical equipment. The NRC has granted some requests.
Next Page: "Defense-in-Depth" >>
Pages 1 2 3 4 5 6