The NRC’s fire protection staff and graphic artists have worked together to create a new introduction to our website’s fire protection pages. The illustrations for the “Prevention,” “Suppression” and “Safe Shutdown” tabs highlight the details in each area of fire protection.
Prevention is a combination of training, NRC inspections and procedures to keep potential fire starters such as welding under control. U.S. reactors have improved their prevention efforts over time. In 1985 they reported 22 significant fires. By the late 1990s, even though more reactors were running, the annual reporting numbers had fallen by more than half. In 2011 U.S. plants reported only six significant fires – less than one fire for every 10 operating reactors.
The next layer of protection involves fighting fires if they occur at or near a reactor. Plants’ fire detection systems are a lot like the smoke detectors in your house. When these detectors go off, however, trained firefighters show up with extinguishers and fire hoses. Many key plant areas also have automatic sprinkler systems. Plants also have plenty of firefighting water available and can get that water onto a fire using onsite staff and equipment or fire engines from nearby communities.
Even with all these measures, U.S. plants must still be able to safely shut down if a fire breaks out. The fire protection approach puts barriers between each reactor’s multiple sets of shutdown equipment, so a fire can’t disable all the equipment at once. The power and control cables are separated to make sure that those systems are available to shut the plant down.
Plants also have alternate control stations if fires disrupt the control room’s ability to manage the situation. The plants have emergency power sources, both installed large diesel generators and portable equipment the NRC required after 9/11. These sources help ensure fires outside the reactor can’t deprive systems of the electricity they need.
Check out the new graphics and fire protection web pages. We hope this information makes the topic easier to understand and gives you a better sense of how layers of protection help ensure nuclear plants remain safe from fires.