Energy Department officials and contractors have known since the 1970s that tanks of liquid radioactive wastes at the Hanford, Wash., nuclear weapons plant could explode, but failed to inform superiors or take corrective action, according to an internal investigation made public yesterday.
The investigation by the Energy Department's Office of Nuclear Safety is one of several parallel inquiries into safety issues at Hanford that have reinforced fears of an explosion in the waste storage tanks and demonstrated that the department is unsure how to cope with the threat.
Two independent panels of nuclear experts disagreed yesterday about the seriousness of the explosion threat. But Sen. John Glenn (D-Ohio), who presided at a hearing about Hanford yesterday, said the Energy Department's management of the Hanford tank farm raises the specter of a mammoth explosion on the scale of the 1957 disaster at Kyshtym in the Soviet Union, which forced evacuation of 10,000 people.
Leo P. Duffy, the Energy Department's waste management director, said he recently visited Kyshtym and concluded that "the situation at Hanford is quite different" because the temperatures of the wastes are kept low enough to avoid an explosion. But he acknowledged that the department's only proposed method of disposing of the wastes -- vitrification, or fusion into glass that would be stored in an underground repository -- is being reevaluated because of technical problems with a similar program at the Savannah River, S.C., plant.
The 570-square-mile Hanford reservation was created from scratch on the plains of eastern Washington in 1943 to produce plutonium for the first nuclear bombs created by the Manhattan Project. Its production reactors are inactive now, and the facility's principal mission is to clean up after itself -- a task that is proving dangerous and expensive.
More than 64 million gallons of radioactive and toxic liquid wastes from plutonium processing are stored underground at Hanford in 149 single-shell tanks and 28 double-shell tanks. More than 1 million gallons are believed to have leaked into the ground since the early 1950s.
Last October, Glenn's Governmental Affairs Committee made public a 1984 Energy Department study indicating that ferrocyanide wastes in the single-shell tanks or hydrogen gas emitted by wastes in the double-hull tanks could explode, with what Glenn called potentially "catastrophic consequences."
One tank in particular, known as SY101, is regularly "burping" hydrogen, defying scientists' efforts to find the cause. Glenn's staff has reported that at least three "major steam explosions" occurred in the 1950s and 1960s.
On July 23, Energy Secretary James D. Watkins's Advisory Committee on Nuclear Facility Safety informed him that "the waste tanks are a serious problem. The possibility of an explosion of an unstable chemical (such as ferrocyanide) or a flammable gas must be taken seriously because the magnitude of the radioactive inventory available for dispersal."
The board's chairman, John F. Ahearne, said members worried that "the operating staff appears to be unconcerned about the hazard" and apparently assumes that because no serious accident has occurred, none will. Ahearne said yesterday that such an attitude is "a prescription for potential disaster."
But a similar panel, the congressionally appointed Defense Nuclear Facilities Safety Board, has shown less alarm. Consultants hired by that panel told Chairman John T. Conway in April that "the team found little cause for concern with the Hanford waste storage tanks" other than SY101.
Conway told Glenn yesterday that his group has found a "low probability" of an explosion in the single-shell tanks. "The potential for a spontaneous chemical explosion in the double-walled tanks is not well understood at this time, although evaluation of the existing information indicates there does not appear to be an imminent hazard to the general public," he said.
Peter M. Blush, director of the Energy Department Office of Nuclear Safety, who directed the investigation of the waste tank history, said department employees and the contractors who have run the plant have known since the 1970s that the tanks were potentially explosive, but did not take appropriate safety measures.
The DOE regional office did not supervise the contractor closely enough, his report said, failed to investigate reported problems and exhibited "generally inadequate" sensitivity to safety issues. Blush attributed these failings to "complacency, a lack of discipline in operations, poor management" and other failures.
The department's Hanford manager, Mike Lawrence, resigned last month. Watkins has named a trusted aide, John D. Wagoner, to replace him.
Ron Bliss, waste management vice president of Westinghouse Hanford Corp., principal contractor at Hanford, said Blush's report was "very unbalanced." He said much of it focused on events in the 1970s, before Westinghouse arrived on the scene.
"I don't agree that there has been a plot to keep this material quiet," he said. Existence of the hydrogen buildup has been shown in safety reports for many years, he said. With all the other problems afflicting Hanford, it "wasn't a high priority" because it was so well known.