By John Altdorfer
Photographs Courtesy of U.S. Dept. of Energy

As mountains go, Yucca Mountain doesn’t really measure up. A crooked spine of dusty volcanic ridges, it nearly blends into the desolate landscape as it crisscrosses the Nevada desert, some 160 kilometers northwest of Las Vegas. Rising barely 300 meters from its base, Yucca Mountain fails to inspire the imagination of climbers, artists, or tourists. Yet, for scores of scientists and engineers, the rambling rock formation provides a towering source of motivation as they work toward creating a safe, permanent repository for America’s nuclear fuel waste products.

Rock-Solid Proof

“The Yucca Mountain Project is an incredible scientific challenge,” says Peggy McCullough, vice president and deputy general manager of Bechtel SAIC, a joint-venture company of Bechtel and Science Applications International Corporation. “There is a tremendous amount of brainpower and creativity at work here.”

In the early 1980s, the U.S. government green-lighted the initiative to find a safe, secure way to dispose of the nation’s growing nuclear waste. Almost immediately, hundreds of world-class engineers, geologists, seismologists, volcanologists, chemists, and other specialists converged on Yucca Mountain. After receiving a five-year government contract in February 2001, nearly 2,000 Bechtel SAIC employees and subcontractors built on that 20 years of research to conduct even more extensive studies, computer modeling, and sophisticated analytic surveys exploring the site’s repository potential.

“Yucca Mountain has all the geotechnical characteristics the government mandated for a waste site,” says Michael Voegele, Bechtel SAIC senior technical advisor. “There’s no place like it in the United States.”

Located at the edge of a parcel of land officially known as Area 25—part of a nuclear testing site established by President Truman—Yucca Mountain is far from any population centers.

Water Safety

“It’s all about protecting and preserving the safety of the water,” Voegele says. “We can bury waste there roughly 300 meters below ground surface and still be 300 or more meters above the water table.” He also points out that there is no free water in the rock that could corrode the canisters holding the waste. Some of the stone in the mountain is like a sponge. It will only transmit water after it is saturated, and because rainfall averages only six inches a year, “Yucca Mountain will be in a desert even when the next Ice Age comes along.”

Laying out a game plan for the next 10 millennia presents more than a few challenges. One of the biggest for Bechtel SAIC is convincing the U.S. government that Yucca Mountain will endure the test of time.

“It is a very difficult calculation,” says Voegele. “We’ve built some 13 kilometers of test tunnels that provide access to study processes governing water movement in the mountain, and we’ve drilled more than 450 boreholes to help understand the water table surfaces.” And that’s only the start. In a 46-meter-long, full-scale repository simulation, containers are filled with electrical resistance heaters to determine how the mountain will react to the heat of nuclear waste. And some 6,000 measuring instruments help scientists understand how water moves through the rock in response to that heat. “There’s never been a test on that scale or level of detail,” says Voegele.

Ultimately, the proof of Yucca Mountain’s suitability lies in multiple lines of evidence. “We’ve prepared a design, written up the scientific documents, and spent hundreds of millions of dollars on the most advanced testing to back up the results of 20 years of drilling and research at the site,” says Voegele. “Now we need to build a case for believable projections of how things will work thousands of years in the future.”

Ready for Construction

With the future always in sight, Bechtel SAIC in November 2004 delivered a 5,000-page draft of the license application the U.S. Department of Energy will eventually submit to the U.S. Nuclear Regulatory Commission (NRC). Although the NRC approval process could take up to three years, the team is preparing for day one of construction.

“When the license is approved,” says McCullough, “we’ll start drilling holes for 66 kilometers of emplacement tunnels zigzagging across the inside of the mountain. Each tunnel will be five meters in diameter, with a flat-bottomed insert so the canisters can be placed inside.”

To reinforce the natural strength of the mountain, structural supports will line each horizontal tunnel. When completed, remotely operated robots will fill the tunnels with the 4.5-meter-long, 1.5-meter- diameter canisters and seal the tunnels. Current plans call for the site to receive radioactive waste for 25 years, and then to monitor the waste for an additional period before Yucca Mountain is permanently shuttered.

As Bechtel SAIC moves forward at Yucca Mountain, nations around the globe are paying attention. “The conclusion of every country looking at the issue is that the only ethical solution is to place these wastes underground, as safely as possible,” says Voegele. “No one wants to leave their waste where it is now. For the United States, Yucca Mountain is the best option.” In the United States alone, radioactive waste now sits in aboveground pools of water at 74 nuclear power plants—not the safest or most secure storage method.

“This project is unique,” says Allen Benson, director of communications for DOE’s Office of Repository Development. “The United States is the only country to have a disposal site like Yucca Mountain. And the rest of the world will be watching to see how well we succeed.”

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