DOE says heat of nuke waste casks would prevent corrosion at Yucca

Benjamin Grove

Wednesday, May 14, 2003 | 10:03 a.m.

WASHINGTON -- Metal containers of nuclear waste are not likely to corrode in the Yucca Mountain repository tunnels because the casks will be so hot they will blast away moisture for at least 1,000 years, Energy Department officials told a review panel Tuesday.

The issues of container corrosion and possible radiation leaks are key to winning approval from the Nuclear Regulatory Commission for the storage of high-level nuclear waste at Yucca Mountain for 10,000 years.

Department laboratory officials provided detailed arguments in support of the project at the regular meeting in Washington of the Nuclear Waste Technical Review Board, a panel appointed by Congress to watchdog the Yucca project. The meeting continued this morning.

Bo Bodvarsson, director of earth sciences for the Lawrence Berkeley National Laboratory, said Tuesday that the tiny amount of water that could seep down into the mountain and into the tunnels would be driven away by heat for at least 1,000 years, possibly 2,500 years, because the Energy Department is embracing a "hot" repository design. The hot design calls for the heat-emitting waste casks to be placed just inches apart, causing higher temperatures in the tunnel.

And Mark Peters, science and technology project manager at Los Alamos National Laboratory, said that even if the "seepage" water entered the tunnels, it would be "benign" to waste containers. He said the chemical makeup of the kinds of moisture in the Yucca tunnels that could corrode the casks is rare and found in small quantities. Peters also said the dust or salts that could accumulate on the casks would not initiate corrosion.

Joe Farmer, senior scientist for chemistry and materials science with Yucca contractor Bechtel SAIC, said studies had proven that samples of alloy 22, the metal that likely would be used to fabricate the waste containers, have not corroded in tests in which the Yucca environment was simulated.

But Nevada experts believe corrosion is a serious problem that Energy Department officials have not adequately studied. The Nevada Nuclear Projects Agency, in its own study, has found that alloy 22 would not be immune to corrosion during the 10,000-year lifetime of the repository.