LOS ANGELES -- The mixing system planned for the Hanford vitrification plant's high-level radioactive waste could wear out in only a few months rather than last the 40-year lifetime of the plant, according to a union official and Department of Energy documents obtained by Hanford Challenge.
Despite the concerns raised in the documents, DOE gave Bechtel National, its contractor for the vit plant, the go ahead to complete fabrication of the tanks that use the mixing system, according to Hanford Challenge.
A federal engineering review team found in late July that Bechtel's safety evaluation of key equipment at the $12.2 billion plant was incomplete and that "the risks are more serious" than Bechtel acknowledged when it sought approval to continue with construction, the documents say.
Senior scientists at the site said in emails that Bechtel's designs for tanks and mixing equipment are flawed and work should be stopped on that part of the construction project. However, DOE told Bechtel National on Aug. 3 that it could proceed, according to Hanford Challenge.
The same day, Richard McNulty, president of the American Federation of Government Employees Local 788, filed a stop work order, which any Hanford worker with a safety concern has the authority to order.
It was quickly overridden by management, according to Hanford Challenge.
Two days later, the union filed a grievance alleging that DOE management violated DOE safety orders and regulations. The union represents DOE scientists and engineers.
DOE officials in Washington, D.C., responded to allegations, saying they believed the problems were fixable and that they had authorized Bechtel to keep going for the time being.
Bechtel officials said Friday that the matter was not a safety issue and that sticking to the current construction schedule would save money.
Whether the mixing system would operate safely became a high-profile issue at the vitrification plant last summer, when Walter Tamosaitis, the researching and technology chief for Bechtel subcontractor URS Corp., was abruptly removed from his job at the plant. He has filed a whistleblower lawsuit claiming he was removed for raising operational safety concerns, which Bechtel has denied.
The vit plant is being built to turn up to 56 million gallons of radioactive waste left from plutonium production at Hanford into a stable glass form for disposal. Adequate mixing is required to prevent plutonium from building up at the bottom of the tanks, risking a criticality, and to prevent the build up of explosive hydrogen gas.
Pulse jet mixers have been designed that suck up waste and then shoot it back out to keep high-level radioactive waste mixed without using moving parts into the tank. The equipment will be too contaminated to allow humans to enter the tank area make repairs once the plant starts operating.
A government engineering team and a separate safety team evaluated the Bechtel design and determined that it did not meet safety requirements set by DOE, and that Bechtel had failed to justify a request to continue construction.
In an Aug. 2 letter, Dale Knutson, the DOE project manager for the vit plant at Hanford, told Bechtel officials that their requests to continue construction had "insufficient information for demonstrating that the ... vessels will meet their credited safety functions."
But Knutson authorized Bechtel to continue construction anyway, including welding shut tanks. Bechtel officials said that welding the tanks shut now would not prevent modifications later if additional testing showed they were necessary.
That authorization has fueled a new round of turmoil among engineers and scientists who had found Bechtel's design deficient, McNulty said.
"Clearly, the management system or safety culture is broken," said Donald H. Alexander, a chemist in the division of nuclear safety, in an Aug. 2 email to top DOE officials. "I find the behavior of management to be appalling."
Alexander said he was pressured to concur on technical issues but refused, and that top managers at the project had attempted to discredit his technical work.
A series of tests with nonradioactive materials in the past year showed that the mixing system wore out in only a few months, according to McNulty and DOE documents.
Significant erosion was found on equipment called "wear plates" installed at the bottom of the tank, according to Hanford Challenge.
If the mixers wear out or fail once highly radioactive material is flowing through the tanks, it would be theoretically impossible to fix the problem and could paralyze the project, the scientists say.
After consulting with his membership, McNulty sought a stop-work order from Knutson, asserting that the decision to proceed presented an imminent safety hazard.
"The design of the tanks is flawed," said Tom Carpenter, Hanford Challenge executive director. "The tests showed it and the safety engineers showed it. The decision to let Bechtel continue transfers the economic risk to the taxpayers. It amounts to a decision to approve a defective design."
Energy Department spokesman Jen Stutsman defended the decision, saying the tanks will not be installed until additional testing demonstrates whether the mixing system will work.
"We will not allow the vessels to be installed until the results from large-scale testing have shown that the vessel designs will safely and effectively handle the waste at the site," she said. "The Department of Energy is continuing to closely oversee the design, construction and testing of the ... plant to ensure that it will operate safely and effectively."