(Last updated 7/12/11)
Nuclear energy facilities use independent scientists to estimate the most powerful natural disasters possible within 200 miles of the plant – and then design and build it to endure forces even more powerful. This approach doesn’t just meet federal government standards, it exceeds them.
A typical reactor is protected by about four feet of steel-reinforced concrete with a thick steel liner, and the reactor vessel is made of steel about six inches thick. Steel-reinforced concrete containment structures are designed to withstand the impact of floods, hurricanes, tornadoes and earthquakes.
Within days of the disaster in Japan, the U.S. nuclear energy industry began triple checking the capability of America’s reactors to respond to severe natural events. Specific actions included verifying required materials and equipment are properly located to protect them from a flood, earthquake or other natural phenomena. Specific criteria to protect these facilities from flood damage include:
- When developing tsunami protection plans, plant operators and regulators assess historical data, including wave propagation models and other natural events.
- Each facility is required by federal regulators to have a tsunami and flood protection plan tailored to its specific location. When the Missouri River rose to record flood levels this summer, two reactors in Nebraska took measures to remain safe.
- Among the measures taken by the electric power industry, electric generators are typically positioned and protected in ways that prevent damage from floods, earthquakes and other natural disasters. Fuel tanks for back-up generators are stored underground in a vault or elevated, making them resistant to flooding, even a tsunami.
U.S. nuclear energy facilities have demonstrated their ability to operate safely through extreme conditions. During Hurricane Katrina in 2005, power supplies from the electric grid were curtailed to the Waterford nuclear energy facility in Louisiana, but the plant shut down safely. It maintained safe shutdown conditions on emergency diesel generators for three and a half days until power from the grid was restored.