|FIND A BUSINESS||» OR Search By Biz Name, Location|
New questions raised on Davis-Besse's safety
07/16/02John Mangels and John Funk
Plain Dealer reporters
A watchdog group is raising serious new concerns about the Davis-Besse nuclear power plant, including the possibility that bacteria are boring through the steel barrier that shields the reactor from the outside world.
The Union of Concerned Scientists also questions whether the radiation monitors inside Davis-Besse and many other plants may fail when they are needed most, during an accident.
The organization, well regarded by the Nuclear Regulatory Commission, is worried that neither Davis-Besse's operators nor the NRC itself is identifying and correcting such problems while the crippled reactor is undergoing extensive repairs.
"There is pitifully little information being released that suggests, let alone demonstrates, that the company is backing its words with actions," David Lochbaum, nuclear safety engineer for the Union of Concerned Scientists, said in a letter yesterday to the federal regulators who are overseeing Davis-Besse.
The scientists' group has a long history of measured, scientifically based critiques of the nuclear power industry.
Lochbaum is a 17-year veteran of nuclear plants and is considered an authority on safety matters.
The NRC is taking a much more passive role at Davis-Besse than the commission has in investigations of accidents and near-misses at other plants, Lochbaum said.
This is why his organization and 14 others want an independent review before the government allows the plant to restart.
The NRC has been concentrating on FirstEnergy's plan to replace the reactor's damaged lid, a process that has never before been attempted in this country. It also is investigating how the damage could have gone undetected. NRC officials "haven't gotten down to some of the other issues," Lochbaum said. Also, FirstEnergy has been less forthcoming with the NRC than have other nuclear operators in similar situations, he said.
The NRC is studying Lochbaum's concerns and an independent review but had no comment yesterday. "Obviously we'll take a look and respond," said spokesman Jan Strasma. Some of the 14 safety questions that Lochbaum raised may be discussed today, when the Davis-Besse oversight panel meets in Oak Harbor, near the plant, 23 miles east of Toledo.
The NRC began investigating the plant in early March, after FirstEnergy workers performing a repair on the reactor's lid accidentally discovered that boric acid in the reactor's coolant had leaked through cracks and eaten a hole the size of a bread loaf all the way through the 6½-inch-thick metal.
Only a thin sheet of stainless steel kept the radioactive coolant from spewing out of the reactor and into the containment building, in what could have been a major accident.
The containment building's last and biggest barrier to keep radiation from escaping the plant is a nearly 300-foot-tall steel "can," or liner. One of Lochbaum's concerns is the condition of that liner; specifically whether tiny organisms in soil and groundwater might be devouring the 1½-inch-thick steel from the outside, in an area that's difficult to inspect.
Davis-Besse two years ago reported to the NRC that water had seeped through the waterproof membrane that surrounds the foundation of the 2½-foot-thick concrete containment building, passed through pores in the concrete wall and puddled in small areas next to the steel liner.
At the time of the inspection, the visible portion of the liner did not appear to have been damaged, the company's report said. The parts of the liner embedded in concrete couldn't be examined, but conditions there were less likely to allow corrosion, the inspectors reasoned.
FirstEnergy didn't propose doing anything about the leak, and the NRC didn't seek any action, Lochbaum said. At the time of the inspection, the company discounted the possibility that the groundwater leaking into the containment building might contain types of bacteria known to have caused damage at other plants. However, the NRC warned of such a scenario as long ago as 1985, in one of several advisories it issued to nuclear plants about "microbiologically induced corrosion." Bacteria capable of boring into construction materials have been found in everything from soil and water to oil, the NRC notice said.
FirstEnergy workers "deluded themselves that untreated groundwater at Davis-Besse, unlike untreated groundwater elsewhere on the planet, cannot contain harmful micro-organisms," Lochbaum wrote yesterday.
That same lack of caution led the company to allow leaking boric acid to remain on the reactor's lid for years, in the belief that it would never corrode through the metal, he said.
FirstEnergy last week ordered tests of the water found at the leak sites for the presence of bacteria, spokesman Todd Schneider said. The results will not be known for several weeks. The company, at the suggestion of NRC officials, plans to test the entire containment liner for leaks later this summer.
The other major concern that has emerged from Davis-Besse's near-miss is the vulnerability of radiation monitors inside the reactor building. The continuously operated monitors are supposed to give reactor operators information about the level of radiation - a powerful indicator of possible reactor leakage.
In the event of an accident, the monitor readings help operators determine the condition of the reactor core and help company and safety officials make decisions about evacuation.
The monitors at Davis-Besse repeatedly malfunctioned during the last four years because their air filters were choked with airborne rust from the corroding reactor lid. Workers had known of the problem since 1999 but were unable to pinpoint its source.
Lochbaum's worry is that if such a small leak was capable of disabling the monitors, a major rupture of reactor piping and the resultant haze of steam and debris would quickly have the same effect, depriving operators of information during conditions that could lead to a meltdown.
Radiation monitors at other nuclear plants are similar to those at Davis-Besse, and thus would be susceptible to the same problem, Lochbaum said. The NRC apparently has not considered such a possibility, he said.
FirstEnergy will examine the ramifications of monitor-clogging if the NRC decides Lochbaum's questions merit action, Schneider said. Davis-Besse has other ways of monitoring radiation around the reactor that would not be affected by airborne debris, he said.
To reach these Plain Dealer reporters:
email@example.com, firstname.lastname@example.org, 216-999-4138
© 2002 The Plain Dealer. Used with permission.
© 2002 cleveland.com. All Rights Reserved.