USA | Nuclear Regulators Question Plants’ Safety Preparations

Posted on June 15, 2011



ROCKVILLE, Md.—U.S. nuclear-safety regulators on Wednesday questioned whether nuclear-plant operators are prepared to deal with a lengthy power outage or a natural disaster such as led to a meltdown at a nuclear complex in Japan.

Nuclear Regulatory Commission Chairman Gregory Jaczko, during an NRC meeting here, questioned why the U.S. isn’t better prepared to deal with the loss of power at a nuclear facility. In Japan, the cooling systems at the Fukushima Daiichi nuclear-power complex lost power for hours following a devastating earthquake and tsunami in March, leading to a partial meltdown and radiation releases from the complex.

Mr. Jaczko said U.S. plants are now able to cope with a complete loss of power for four to eight hours and said there was “pretty clear and obvious evidence that that is not sufficient—and that evidence has been there before Fukushima Daiichi.”

“Much of what happened at Daiichi was not new,” Mr. Jaczko said. “None of those things were unknown phenomena.”

Another commissioner, George Apostolakis, also said he was “a little perplexed” at why the ability to cope with power loss had not been extended.

“We are not omniscient,” responded Charlie Miller, a veteran NRC staffer who is heading a task force assigned to review U.S. nuclear-plant safety in light of the Fukushima disaster. He said NRC staff is ready to make changes.

Mr. Miller pointed out a series of possible holes in the nuclear agency’s regime Wednesday, though agency officials reiterated that none of the problems poses an immediate safety risk.

Current rules for a blackout at a nuclear plant don’t fully account for a Fukushima-like scenario in which the plant loses both on-site and off-site power simultaneously, Mr. Miller said.

At Fukushima, an earthquake and tsunami knocked out both the outside power grid and on-site backup generators, hampering crucial cooling systems.

At some U.S. plants, vents designed to relieve pressure and avoid explosions inside a reactor building aren’t designed to be used during a prolonged blackout and might not function properly, Mr. Miller said.

“Depending on plant-specific design, it may be a challenge to open the vent path in a scenario like the Fukushima accident,” he said. He also said that agency inspectors aren’t required to inspect some vents.

Some emergency equipment that could be needed during a natural disaster isn’t required to be protected from a flood or earthquake and hasn’t always been properly maintained, Mr. Miller said.

On another issue, Mr. Miller said plant operators have developed plans for managing a severe accident on a voluntary basis, but they haven’t consistently implemented the agency’s guidelines for maintaining those plans. Meanwhile, he said, agency inspectors weren’t closely checking that operators were ready to execute the plans.

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