U.S. Reactor Back-up Batteries Weak

Monday, April 4, 2011 @ 02:04 PM gHale

Almost all American nuclear power plants have backup batteries that would last only half as long as those at Japan’s troubled Fukushima Daiichi plant did after a tsunami knocked out power there, an expert testified at a Senate committee briefing on nuclear safety.

In addition, just 11 of the U.S.’ 104 plants had eight-hour batteries, and 93 had four-hour batteries. Those batteries are not powerful enough to run pumps that direct cooling water, but they can operate valves and can power instruments that give readings of water levels, flow and temperatures

U.S. reactors with underpowered batteries.

U.S. reactors with underpowered batteries.

An industry watchdog, addressing the Senate Energy and Natural Resources Committee, conceded battery life was “one of the obvious places” that nuclear operators would examine for potential improvements. David Lochbaum, a nuclear expert at the Union of Concerned Scientists, which generally takes a critical tone toward nuclear reactors, said eleven of the nation’s 104 plants had eight-hour batteries, and 93 had four-hour batteries.

After the March 11 tsunami disabled the local electricity grid at the Fukushima Daiichi plant and the plant’s emergency diesel generators, the failure of the batteries deprived the plant’s operators of those crucial measurements.

Addressing the committee with Lochbaum was Anthony R. Pietrangelo, senior vice president and chief nuclear officer of the Nuclear Energy Institute (NEI), the industry trade association. “To get to 48 hours, or 72 hours, pick a number,” he said of the backup batteries. “We’re going to have to take a hard look and see what resources would be required.”

Pietrangelo said one alternative to adding long-lasting batteries could be having portable diesel generators available for quick dispatch to a reactor. There is already a stockpile of some equipment intended to cope with a severe accident or terrorist attack, he said.

Representative Edward J. Markey (D-Massachusetts), said plans to introduce legislation to require that American plants acquire 72-hour batteries along with fourteen days of fuel for the backup diesel generators.

Fukushima reportedly had seven days of diesel fuel, but the tsunami washed the tanks away; most American plants bury their tanks for safety, according to industry officials.

The bill would also impose a moratorium on license renewals and on new plant licenses.

Another expert who spoke before the Senate committee, William Borchardt, the chief staff official of the Nuclear Regulatory Commission (NRC), said the Fukushima crisis would have no impact on the commission’s granting of new licenses or license extensions.

If Japan’s experience shows the U.S. needs changes in reactors, he said, then the changes will take place immediately, regardless of the status of the plant’s license, license extension or license application.

Another American practice that appears likely to undergo reevaluation in view of Japan’s crisis is filling pools with spent fuel to the maximum extent possible. Markey and others called for reducing the risk by moving some fuel to dry casks, something that occurs now only when the pool is at capacity.