A leading scientist is speaking out strongly on design flaws of storage canisters proposed for Yucca Mountain, Nevada, the nations planned depository site for high-level nuclear waste. Paul P. Craig recently quit the Nuclear Waste Technical Review Board and began to amplify his concerns about the shortcomings of the U.S. Dept. of Energy, calling it a schedule-driven massive bureaucracy.
Craig had been a member of the depositorys scientific oversight panel for seven years. His January resignation came on the heels of the departure of Board Chairman Michael L. Corradini, who was criticized for conflicts of interest. Both departures came after a new technical review board report suggesting that radioactive leakage can occur at Yucca Mountain. The news alarmed DOE, which had planned to file an application with the Nuclear Regulatory Commission for the long-awaited projects approval by years end.
Last Oct. 21, the board sent DOE a two-page letter stating that widespread corrosion is likely. Supporting technical evidence said that container corrosion could occur during the thermal pulse phasethe first 1,000 years of stor-
age, when temperatures exceed 95°C.
The DOE container design uses multiple layers of nickel-based Alloy 22 and stainless steel, along with welded lids, to encase spent radioactive fuel rods. The rods are now in temporary storage at nuclear powerplants around the country.
The agency claims that Alloy 22 would permit general corrosion penetration of only 0.03 in. in 10,000 years. Only 1% of the waste packages would lose some of their integrity during the first 10,000 years, the agency predicts.
I am especially concerned about the boards conclusions, responded Margaret S.Y. Chu, director of the Office of Civilian Radioactive Waste Management, in a Dec. 17 letter. Our analyses do not suggest such results.
A scheduled March meeting on seepage, the in-drift environment, and localized corrosion has been post-poned until May 18-19. The DOE has itself in
a box with a design that doesnt work, says Craig, professor emeritus of engineering at the University of California-Davis. They have committed to getting the waste underground by 2010.
Part of the problem lies in Yucca Mountains geology of porous tuff. During the thermal pulse period, heated water inside the rock moves, making thermal conductivity difficult to gauge. Craig says the design could be fixed with more testing, but not on DOEs current timeline. Click here to view chart
Craig is taking findings from the board and drawing implications, which
is beyond the boards mandate, says William D. Barnard, executive director.
Yucca Mountain, 90 miles north of Las Vegas, plays a key role in the Bush administrations National Energy Policy, which calls for 50,000 Mw of new nuclear generation capacity by 2020. A permanent repository would solve a long-standing waste problem: 42,000 metric tons of radioactive plutonium stored at 131 sites in 39 states. The estimated $57.5-billion project would place up to 77,000 metric tons of waste 1,000 ft underground.