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- Nuclear Engineering Professor Questions Feds' Commitment to Yucca Mountain

- Outrage of the Week

Nuclear Engineering Professor Questions Feds' Commitment to Yucca Mountain
A University of Michigan nuclear engineering professor is questioning the validity of the federal government's studies that claim the Yucca Mountain nuclear waste repository 100 miles northwest of Las Vegas is geologically safe for the long-term disposal of 70,000 metric tons of high-level nuclear waste.

In fact, Rodney C. Ewing -- whose multidisciplinary expertise also spans geology and materials science -- is so disturbed by the results of a 20-year U.S. Department of Energy (DOE) study that he is writing a book due in early 2004 which will focus on Yucca Mountain's many unresolved technical issues.

In the March 2003 edition of Scientific American magazine, Ewing states his belief that the amount of research DOE has performed at Yucca Mountain -- based on findings from 75,000 feet of core samples and 18,000 geologic and water specimens retrieved from the site -- are "not the way you measure good science, any more than you judge the merits of a book by the number of words."  He also believes the federal government is tailoring regulations to fit Yucca Mountain, instead of choosing a site that meets existing nuclear waste disposal policies.

Ewing is one of Yucca Mountains' most knowledgeable and credible critics, having served on the Yucca Mountain peer-review panel. According to Scientific American, Ewing believes that the mass of information collected by DOE at Yucca Mountain generates more questions than it answers.

"We've learned a lot about this mountain, but when you look at the substance of it, our knowledge is actually quite thin," Ewing told the magazine.

The crux of the DOE's Yucca Mountain risk evaluation is a computer calculation that attempts to predict the fate of nuclear waste buried there for thousands of years.  Because this "probabilistic performance assessment" found no potential flaws, DOE pushed for development of Yucca Mountain and, in 2002, the Bush administration and Congress approved the site.  DOE is expected to file for a construction permit by late 2004, after which the Nuclear Regulatory Commission (NRC) will have four years to determine the repository's future; with NRC approval, DOE can then begin construction.

However, Ewing believes there are myriad problems associated with the government's exclusive investment in Yucca Mountain.  Primarily, he argues that the DOE has changed the rules of the game to fit the site. Most notably, DOE abandoned the long-standing, traditionally-held geologic disposal philosophy of "defense in depth," which relies on favorable geology and engineered barriers to isolate nuclear wastes. Instead, DOE adopted site-specific standards to meet the needs of Yucca Mountain. 

"Instead of devising a regulation and finding a site that meets it," Ewing said, "we picked a site and made a regulation for it."

Ewing also cited other examples where the government's research has fallen short of addressing the dangers of storing nuclear waste at Yucca Mountain.  For example, he said the Environmental Protection Agency's (EPA) designation of 18 kilometers (about 11 miles) as the point for measuring radioactive exposure is too distant from the source, and that the 10,000-year limit for measurements is too short as exposures likely will peak millenia later.

"We should do the analysis first to find out when the peak dose occurs, rather than setting the time limit in advance," he said.

Geologic variables as potential seismic and volcanic activity are inadequately addressed, Ewing said, adding that long-term corrosion rates for Alloy 22, a relatively untested metal which is being proposed for containers that will store nuclear wastes at Yucca Mountain, are difficult to predict. 

"We're betting on a new material about which we know little, while making optimistic assumptions about its behavior under conditions we can only guess at," Ewing said. "Uncertainties throughout the model are rolled together, which makes it hard to tell whether any of the barriers are effective."

Despite his concerns over Yucca Mountain, Ewing -- according to Scientific American -- maintains his belief in the validity of geologic waste disposal and nuclear power.  He supports the underground Waste Isolation Pilot Plant (WIPP) in New Mexico (Ewing served on the project's review panel), where work started in 1999 after 20 years of study.  Contrasting WIPP to Yucca Mountain, Ewing said nuclear wastes at the New Mexico facility are not as "hot," meaning a much smaller amount of radioactivity will ultimately be stored there.  While reducing the possibility of thermal problems, the geology at WIPP also is much simpler than Yucca Mountain, meaning there are fewer issues related to water and potential seismic and volcanic activity, according to Ewing.

As the Yucca Mountain project progresses, Ewing sees little opportunity for further scientific input at the site. "The game is not rigged like a crooked card game, but the lack of choice at every step drives us inexorably to Yucca Mountain," he said.

However, Ewing has not halted his battle against the project: In collaboration with geologist Allison Macfarlane of the Massachusetts Institute of Technology, he is writing a book due in 2004 about the government's failure to adequately address scientific issues associated with Yucca Mountain.

(Editor's note: The complete profile of Prof. Rodney C. Ewing can be viewed by visiting http://www.sciam.com/article.cfm?articleID=0004CF54-4981-1E40-89E0809EC588EEDF&catID=2)