TVA says reactors designed to handle big earthquakes

The nuclear reactor that exploded in Japan on Saturday is similar in design to TVA's oldest nuclear power plant at Browns Ferry in Alabama.

In fact, the Fukushima Daiichi plant was designed to withstand a stronger earthquake than Browns Ferry, which like the damaged Japanese plant is a General Electric Mark 1 boiling-water reactor.

"It's hard to believe in the wake of this accident that nuclear power is safe, reliable or cheap," said Sandy Kurtz, a Chattanooga anti-nuclear activist who is part of a group fighting TVA plans to build another nuclear plant in Hollywood, Ala.

The Fukushima plant was struck by an 8.9-magnitude earthquake far greater than any that has ever hit a nuclear power plant. But the quake and the wall of water that flooded and cut off power sources to the plant appear to have combined to lead to problems cooling the reactor core.

TVA spokesman Ray Golden said U.S. reactors are built to handle the biggest earthquakes that have occurred where they are located.

"The Japanese nuclear plants are in a much higher area of earthquake risk and magnitude than are TVA's plants, and we obviously don't have the risk of a tsunami like what we saw in Japan," he said.

TVA's Sequoyah Nuclear plant near Soddy-Daisy and the Watts Bar plant near Spring City each are built to withstand a 5.9-magnitude earthquake, regarded as a moderate quake. Browns Ferry in Alabama, where stronger quakes are possible, is designed to withstand a strong earthquake of up to a magnitude of 6.9.

David Lochbaum, a senior scientist in Chattanooga for the Union of Concerned Scientists, said the Japanese plant explosion underscores the need for U.S. regulators to address the need for better backup power, fire protection and emergency evacuation at U.S. reactors.

The tsunami knocked out the power grid and the Fukushima plant's emergency diesel generators. Battery-powered generators failed to maintain adequate power until other power sources could be restored, Lochbaum said.

Former Nuclear Regulatory Commission member Peter Bradford said the nuclear industry needs better ways to relocate people when accidents happen in cities close to nuclear plants like Chattanooga.

"The viability of U.S. emergency plans at densely populated reactor sites may have to be re-examined to determine whether they can be implemented in the context of a nuclear accident precipitated by a natural disaster," Bradford said. "This was always a theoretical possibility. Now it's real."