David Lochbaum, a nuclear engineer who serves as director of the Nuclear Safety Project with the Union of Concerned Scientists, has the credentials to know whereof he speaks. From March 2009 until March 2010, Lochbaum worked for the Nuclear Regulatory Commission as a Boiling Water Reactor technology instructor at their Technical Training Center.
His duties included teaching the severe accident management guidelines to NRC employees for their initial qualifications and requalifications.
Lochbaum was asked to testify before a joint session of the Energy and Environment and Investigations and Oversight Subcommittees of the House of Representatives Committee on Science, Space, and Technology.
The hearing was held in view of the ongoing nuclear crisis at the Fukushima Daiichi power plant on Japan's Pacific coast after the March 11 earthquake and tsunami destabilized the facility.
Today Tokyo Electric Power Co. officials confirmed that a nuclear fuel meltdown has occurred at one of the plant's six boiling water reactors, and the entire reactor building will be sealed in a covering to prevent further releases of highly radioactive substances.
FirstEnergy's Davis-Besse nuclear power plant is located on the southwest shore of Lake Erie 10 miles north of Oak Harbor, Ohio. (Photo courtesy NRC)
Lochbam told the lawmakers, "Some may argue that what happened at Fukushima Daiichi cannot happen here - that our nuclear power plants are not vulnerable to extended power outages caused by the one-two punch of an earthquake and tsunami."
However, he said, "In June 1998, a tornado disabled the normal power supply for the Davis-Besse nuclear plant in Ohio, just as the earthquake had done for Fukushima Daiichi."
"Outside air temperatures exceeding 90 degrees caused the backup power supply to overheat and fail, just as the tsunami had done at Fukushima Daiichi. The difference was that workers restored the normal power supply for Davis-Besse an hour before the backup power supply failed, while more extensive damage prevented workers at Fukushima Daiichi from restoring its normal power supply for nearly a week, days too late to prevent fuel damage," Lochbaum said.
In NRC terminology, a severe accident is one in which at least some of the fuel melts," said Lochbaum. "In testimony at Congressional hearings, NRC and nuclear industry representatives have claimed that the severe accident management guidelines (SAMG) developed in the wake of reactor meltdown at Three Mile Island would provide reliable protection against the problems faced at Fukushima Daiichi. They have not been telling the whole story."
"As newscaster Paul Harvey used to say, here's the rest of the story."
Lochbaum pointed to a page in the NRC Manual covering the agency's reactor oversight process.
He said, "The fourth column for the severe accident management guidelines entry states: 'The [NRC] staff concluded that regular inspection of SAMG was not appropriate because the guidelines are voluntary and have no regulatory basis."
"The NRC never checks - repeat, never checks - the guidelines to see if they would be effective under severe accident conditions," Lochbaum emphasized.
When he taught severe accident management guidelines to NRC employees for a year starting in March 2009, Lochbaum said, "I and the other instructors emphasized that NRC inspectors were not authorized to evaluate the adequacy of the guidelines. Plant owners are required to have the guidelines while NRC inspectors are required not to assess their effectiveness. It's like maritime inspectors ensuring that passenger liners have lifeboats, but not checking to see that there's sufficient capacity for all passengers and crew members."
"If NRC continues to rely on these guidelines to protect public health, it must evaluate their effectiveness," Lochbaum told the committee members. "It would be too late and too costly to find out after a U.S. nuclear plant disaster that the plant's severe accident management guideline was missing a few key steps or contained a handful of missteps."
Lochbaum also recommended that U.S. nuclear power plants store their spent fuel in dry casks rather than in spent fuel pools, as many do now.
Dry cask storage of nuclear fuel (Photo courtesy NRC)
The fuel stored in dry casks at Fukushima Daiichi experienced the earthquake and the tsunami, said Lochbaum. "It experienced the prolonged power outage. It did not overheat. It was not damaged. It did not produce hydrogen that later exploded. It did not cause the evacuation of a single member of the public. It did not cause a single worker to receive radiation over-exposure."
"The spent fuel pools at nuclear plants in the United States are significantly fuller than those in Japan. As a result, the chances of a spent fuel accident are higher and the consequences would be greater," he warned.
For the first five years after being taken out of the reactor core, spent fuel generates too much heat to be placed into dry casks. After five years, the heat generation rates have dropped low enough to permit dry cask storage, he explained
"It takes no pumps, no power, no switches, and no forced circulation of water to protect spent fuel in dry casks from damage. Instead, air enters an inlet in the bottom of the dry cask, gets warmed by the heat from the spent fuel, and flows out an outlet in the top of the dry cask via the chimney effect. It's the "passive" safety system that worked at Fukushima Daiichi and would work here, if we bothered to use it."
"Instead," explained Lochbaum, "spent fuel pools in America are filled nearly to capacity. Then and only then is spent fuel transferred into dry casks. But the amount of spent fuel transferred is just enough to free up the space needed for the next fuel discharged from the reactor core. This practice maintains the spent fuel pool risk at a level about as high as can be achieved, and exposes millions of Americans to elevated and undue risk."
"The safer way to store spent fuel is to transfer it into dry casks as soon as possible following the five year cooling off period in a spent fuel pool," he said. That's the 'passive' safety system Americans need most."
Republican members of the subcommittees spent their time berating the U.S. Department of Energy for not providing a witness.
Testifying today, Dr. Brian Sheron, director of the Office of Nuclear Regulatory Research at the Nuclear Regulatory Commission, said that efforts are being made to address new concerns.
"Our program of continuous improvement based on operating experience will include evaluation of the significant events in Japan and what we can learn from them," Sheron said.
Exelon's LaSalle nuclear power plant is located 75 miles southwest of Chicago, Illinois. (Photo courtesy Exelon)
"The NRC already has an extensive seismic research program and new information coming out of Japan will be utilized to reassess seismic hazards at existing U.S. plant locations," he said.
Sheron said that "Although no immediate safety issue has been identified, the NRC will take action if our further analysis shows that safety improvements can be justified."
When asked about the safety of existing U.S. nuclear plants, Sheron said there is no evidence that existing plants are not safe.
Lochbaum warned that earthquakes and tsunamis are not the only hazards that can cause the complete loss of power known as a "station blackout."
"Station blackouts constitute 80.6 percent of the overall core damage risk at the LaSalle nuclear plant in Illinois," he said pointing to a chart of station blackout risk prepared by nuclear power plant owners themselves.
"In other words," Lochbaum warned, "the risk from station blackouts is roughly four times the risk from all other causes combined. And LaSalle is located far away from the earthquake faults of California and the tsunami risks of both coasts, so clearly an earthquake and tsunami is not the only path to a station blackout disaster."
Copyright Environment News Service (ENS) 2011. All rights reserved.