FOR IMMEDIATE RELEASE: December 12, 2002
Contact: Bob Loux at (775) 687-3744 or
Dana Pretner at (702) 967-2222 or (702) 682-7565
LABORATORY EXPERIMENTS INDICATE THAT METAL ALLOY NUCLEAR WASTE CONTAINERS AT YUCCA MOUNTAIN WILL IN TIME DISSOLVE
Scientists: Moisture, heat, other conditions could imperil containers
(Las Vegas) - Scientists working for the State of Nevada today told the National Academy of Sciences' Board of Radioactive Waste Management that metal alloy containers designed to hold high-level nuclear waste at the proposed Yucca Mountain nuclear waste repository will quickly dissolve under expected Yucca Mountain conditions.
Dr. Roger Staehle and Dr. Don Shettel conducted the experiments at Catholic University using conditions simulating those anticipated at Yucca Mountain, 90 miles northwest of Las Vegas. They told the board that given the expected natural conditions at Yucca Mountain - including moisture and heat - manmade metal alloy containers will not safely hold high-level nuclear waste for the required regulatory period, but in time will dissolve.
"These findings reinforce our belief that the U.S. Department of Energy and the Nuclear Regulatory Commission have long used fuzzy science to prop up their plans to dump the nation's nuclear waste in Nevada," said Nevada Nuclear Projects Agency Executive Director Bob Loux. "Once again, the scientific facts are proving the fallacy of DOE's assertion that Yucca Mountain is safe for the long-term storage of nuclear waste."
A critical element of the proposed Yucca Mountain repository is an engineered barrier system incorporating nuclear waste canisters composed of C-22 Hastelloy and a drip shield made of titanium-7 metal. The drip shield is designed to divert any water seepage and prevent it from reaching the waste canisters.
Dr. Staehle and Dr. Shettel have been conducting laboratory experiments to assess the stability of the two key barrier metals, C-22 and Ti-7, under anticipated repository conditions. These conditions include rock dust and precipitates covering the drip shield and hot canisters; fracture and rock-pore water dripping and flowing; microbial/fungal reactions; and man-made intrusive materials.
Using simulated Yucca Mountain pore water, Dr. Staehle's and Dr. Shettel's experiments strongly suggest that heating in the repository will produce a powerful acid vapor called aqua regia, which is so potent it even dissolves gold. As this caustic vapor condenses and evaporates, concentrated acid and solid precipitates form. The solid precipitates in turn attract water vapor from the air and form additional very strong acids. Under these conditions, at temperatures ranging from 70 degrees Celsius (158 degrees Fahrenheit) to 145 C (293 F), the engineered-barrier metals C-22 and Ti-7 dissolve.
The scientists' findings just add to the list of problems with C-22 and Ti-7. Previously, laboratory results showed that lead, mercury, fluorine, and possibly other trace elements in the water and rock of Yucca Mountain would hinder the ability of C-22 and Ti-7 to contain the nuclear wastes for the required period of time.
DOE's performance models for Yucca Mountain depend heavily on these containers to meet safety regulations, as the geology contributes almost nothing to waste isolation. " If the waste containers won't perform as DOE predicts, and the geology plays nearly no role in containing the waste, the site should be abandoned," said Bob Loux, Nevada's nuclear agency head.