A scientific advisory panel's warning about metal casks corroding at high temperatures and releasing radioactivity will not slow plans to build a national nuclear waste dump in the Nevada desert, the Energy Department said Wednesday.
"We have long studied the issues of corrosion at Yucca Mountain," DOE spokesman Joe Davis said in response to a letter of concern from the Nuclear Waste Technical Review Board.
"What it comes down to is whether the repository is operated at lower temperatures or higher temperatures," Davis said from Washington, D.C.
He said the Energy Department's application to the Nuclear Regulatory Commission to license the repository 90 miles northwest of Las Vegas would answer the review board's concerns. The Nuclear Waste Technical Review Board was created to monitor technical and scientific performance at the Yucca Mountain project and report to Congress.
"No matter what our design, we believe we can meet the environmental and regulatory standards for operating the repository," Davis said.
In a letter to Margaret Chu, the federal official in charge of the repository, review board members said that at extreme temperatures of 200 to 300 degrees Fahrenheit given off by the stored radioactive material, water seeping into repository tunnels will react with salts from the soil and eat away at flaws in containment canisters.
"Because of the seriousness of these corrosion concerns, we strongly urge you to re-examine the current repository design and proposed operation," the letter states. "The board believes that the high temperatures of the current design and operation will result in perforation of the waste packages."
David Duquette, a board member who co-authored the letter, said the panel did not address whether radioactivity released from the stored nuclear waste would be lethal.
"This isn't necessarily a show-stopper," said Duquette, chairman of the science and engineering department at Rensselaer Polytechnic Institute in Troy, N.Y. "We're suggesting to them, 'Get your temperatures down.' If they do that, we would feel more comfortable that the containers would not corrode to the point of failure."
The letter focuses on the performance of casks built of Alloy 22, a combination of nickel and chromium alloys with other elements including molybdenum. Duquette called the alloy the best known material for nuclear waste containers.
Davis said Energy Department and Yucca Mountain scientists think such casks will safely contain spent nuclear fuel at the repository, which is being constructed 1,000 feet under an ancient volcanic ridge.
Spacing the canisters farther apart would reduce the temperature in the tunnels and reduce the corrosion risk, he said.
Plans are still being developed for shipping spent nuclear fuel to Nevada from more than 100 commercial, industrial and military sites in 39 states. Officials have focused on key rail lines running through Chicago and St. Louis, and truck routes from the northeast and southwest converging in Omaha, Neb., before heading west on Interstate 80.
Bob Loux, director of the state Nuclear Projects Office and Nevada Gov. Kenny Guinn's anti-Yucca chief, said the Energy Department has been counting on both man-made and geologic design features to contain radioactivity for the 10,000 years that the federal Environmental Protection Agency requires.
"This is a fairly serious blow to DOE plans," Loux said of the review board's finding. "The waste is lethal for 250,000 years, EPA says the site only needs to perform for 10,000 years. The comments made by the board mirror a state of Nevada study that the canisters are very unlikely to last even 1,000 years."
The Energy Department plans by the end of 2004 to submit to the Nuclear Regulatory Commission an application to open and operate the repository beginning in 2010.
The Bush administration and Congress have approved the site, but the Nuclear Regulatory Commission will decide whether the project may open.
On the Net:
Yucca Mountain project: http://www.ymp.gov/
Nuclear Regulatory Commission: http://www.nrc.gov/
Nevada's Agency for Nuclear Projects: http://www.state.nv.us/nucwaste
Nuclear Waste Technical Review Board: http://www.nwtrb.gov