DOE: Tunnel supports not a priority for Yucca

Benjamin Grove

Tuesday, Nov. 30, 2004 | 11:11 a.m.

WASHINGTON -- Yucca Mountain tunnel supports that prevent rock falls ultimately are not "important" to safely isolating nuclear waste, the Energy Department said.

The tunnel supports include rock bolts, wire mesh and steel sets that would help hold up tunnel walls and ceilings. The supports used to be on the Energy Department's Yucca "Q list," a catalog of project systems and materials that would be important to safely contain radiation in the proposed nuclear waste repository -- and therefore subject to quality assurance rules.

But the department removed the tunnel supports from the list as of July, according to the Nuclear Regulatory Commission.

An Oct. 27 memo written by two Yucca inspectors for the NRC confirmed that project managers had removed the tunnel supports from the Q list after the managers concluded the supports had been "inappropriately classified as important to safety or waste isolation."

"That's the dumbest thing I've ever heard," said Rep. Jim Gibbons, R-Nev., a geologist. "I don't believe that anyone in their right mind would say that the rock bolts and the tunnel walls are not a QA issue. It's always a QA issue."

The Energy Department removed the tunnel supports from the Q list after an analysis concluded the tunnel supports would not officially be a part of the overall Yucca safety system designed to isolate highly radioactive waste from the environment for thousands of years, according to the NRC memo.

The department's models and research suggest that safety strategies such as high-tech alloy metal containers covered by titanium "drip shields" are more than enough to isolate waste.

The tunnel supports are an added measure of safety, but ultimately not a necessary one, according to the department.

"The tunnel support system isn't included in the Q list because the other engineered systems provide for radiological protection," DOE spokesman Allen Benson said.

The Energy Department is wrong about that, Gibbons said. Any tunnel collapse or fracture would create new "avenues of escape" for radiation, Gibbons said.

"It's like putting water in a fractured glass," he said.

Benson added that the tunnel supports are subject to an "augmented" quality assurance program "that addresses the same general areas as our nuclear safety QA program."

But Yucca critics believe the tunnel supports should be subject to the "nuclear safety" Q list. The supports would be vital to ultimately isolating radiation at Yucca and should be subject to the future repository's "QA" safety rules -- even if that means increased costs and trouble, critics said.

"Life gets easier when you don't have to do quality assurance on something," said Judy Treichel, executive director of Nevada Nuclear Waste Task Force. "The DOE is always full of bad surprises."

From the Energy Department perspective, the tunnel supports are important for the construction phase of the repository, not the ultimate performance of it, said David Duquette, a member of the Nuclear Waste Technical Review Board, which was created by Congress to be an independent Yucca watchdog.

That makes sense given that far into the future the tunnel supports likely will fail, which is why the department aims to prove that other safety systems like the drip shields and metal containers will not fail, said Duquette, a metals and alloys expert and professor of materials science at Rensselaer Polytechnic Institute in Troy, New York.

Duquette said the review board has not yet fully examined the next logical question: How would rock falls affect the drip shields? And ultimately, would possible drip shield failure lead to increased corrosion of the waste containers?

Duquette said he has not yet seen a full analysis of that question from the Energy Department.

"We do have some concerns about the drip shield itself," Duquette said.

The tunnel support issue is just one on a long list of challenges the state of Nevada plans to make to the Energy Department's application for a license to construct Yucca. Those challenges are part of a broader argument that the department can't construct a safe repository.

Failed supports could allow rock falls that over time could dent metal nuclear waste containers, Yucca critics said. Eventually that could create cracks or small pits on the container surfaces where corrosive moisture or dust could collect, they said.

"This is just another example of cutting corners to save money and accelerate the project," said lawyer Joe Egan, who is leading legal challenges against Yucca for the state of Nevada.

Significant rock falls also could complicate -- even prevent -- the retrieval of waste inside Yucca, Egan said.

Energy Department officials have said they intend to develop Yucca as a retrievable waste repository. Retrievals in the high-temperature tunnels likely would rely on robotic technology that would be hampered by rock falls.

Retrieving waste during an emergency failure of the repository is vital to the Energy Department's argument that Yucca is safe, critics said.

"I would say that is the ultimate safety matter," said Martin Malsch, a lawyer who works with Egan. "If something happens you want to be able to get the waste the hell out of there."

The "de-listing" of the tunnel supports comes as Yucca quality assurance programs have been under fire.

The NRC, which will be responsible for licensing and regulating Yucca, has been critical of quality assurance.

So has the General Accounting Office, the investigative arm of Congress. In April the GAO reported that quality assurance problems could delay the project. Energy Department officials have said they made changes to improve quality assurance.

But the department may have a tough time convincing the NRC that basic tunnel supports should not be on the Q list, Nevada officials said.

"The DOE has been sloppy on QA for years, and they are still playing catch up, and they still can't get it right," said Steve Frishman, a technical consultant to the state of Nevada.

The NRC cannot comment yet on whether or not removing tunnel supports from the Q list raised any red flags among agency officials, NRC spokeswoman Sue Gagner said.

The NRC will review the matter when it reviews the Energy Department's license application, Gagner said.

The Energy Department had planned to submit the application -- a detailed, technical explanation of the entire Yucca safety system -- by year's end. But department officials last week said that submission will be delayed.