DOE geologist says earthquakes no threat to Yucca Mountain

RENO, Nev. - Large earthquakes are expected over the life of a nuclear waste dump planned at Yucca Mountain but pose no threat of busting open the high-level radioactive repository, a leading government geologist says.

"We expect some relatively large earthquakes," said Tim Sullivan, an Energy Department geologist who led the DOE's most recent viability assessment of the site.

Earthquakes of the magnitude of 6 to 7 have occurred at Yucca Mountain northwest of Las Vegas in the past 10,000 years "and several times in the last 100,000 years," Sullivan said Tuesday night.

"Earthquakes will occur in the future. We can't prevent that. But our systems will be protected from earthquakes," he said in an interview with The Associated Press.

Sullivan was among DOE official who traveled to the University of Nevada, Reno, campus Tuesday to help provide a status report on the proposal to build the repository in Nevada.

Yucca Mountain, a ridge of volcanic rock 100 miles northwest of Las Vegas, is the only site the DOE is studying to entomb the nation's high-level radioactive waste - 77,000 tons of primarily solid, spent fuel pellets from commercial power reactors that will be encased in steel-nickel containers.

Concerns about potential threats due to the temblors reemerged last month after a series of quakes shook the desert northwest of Las Vegas about 35 miles from Yucca Mountain.

The biggest jolt, a magnitude 4.7, struck the Frenchman Flat area on Jan. 27.

Nevada's congressional delegation was quick to publicize the incidents and step up their condemnation of plans to build the repository there.

"This is just another serious warning about the unsuitability of the Yucca Mountain site," Rep. Jim Gibbons, R-Nev., said. "I hope the Department of Energy is taking seriously these early warning signs of geologic instability in the area."

Geologists said the latest earthquakes have been near or along the Rock Valley Fault. That's the same fault geologists believe triggered a much stronger, magnitude-5.6 earthquake at Little Skull Mountain on June 29, 1992.

"These earthquakes are no surprise to us," Sullivan told AP.

"It does not change things. We are well aware earthquakes occur in Southern Nevada," he said.

Sullivan said DOE scientists were doing their best to put the quakes in perspective.

"I recognize there is a public perception and a correct one that earthquakes cause catastrophes," he said.

"But those catastrophic events occur because of poorly designed structures," he said.

Scientists are using 20 years of modern research experience in California to construct the earthquake-proof repository, Sullivan said.

He said the DOE's conclusions must be confirmed by the Nuclear Regulatory Commission, which "has a thorough understanding of earthquake issues."

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