DOE scientists unsure of scenario at Yucca

Wednesday, Jan. 26, 2000 | 12:03 p.m.

Department of Energy scientists expressed doubts Tuesday over whether they will be able to prove their case for a high-level nuclear waste repository at Yucca Mountain, the lone site under consideration for burial of 77,000 tons of highly radioactive waste.

The department is planning to build tunnels 1,000 feet deep inside Yucca, 90 miles northwest of Las Vegas, to keep deadly radiation away from people and the environment. No one has ever built, operated or tested such a project. Priscilla Nelson of the independent Nuclear Waste Technical Review Board, whose meeting in Las Vegas continues today, posed a crucial question late Tuesday: What if the uncertainty increases as the DOE gets more information about a repository at Yucca?

"You've hit a point, the crux of a difficult problem," said Abe van Luik, DOE's senior policy adviser on the Yucca project. He did not say the site would be abandoned.

Van Luik and other DOE scientists conceded that there are many gaps in the scientific knowledge of how Yucca Mountain will perform as a repository over the long haul. Sufficient information could take 125 or more years to gather, van Luik said.

"I have been in meetings with scientists drowning in uncertainties, who left wringing their hands saying, 'This is impossible,' " said van Luik, referring to an international meeting of petroleum experts who said their work was uncertain, but good enough to guide exploration and exploitation for oil..

Between sessions in the hallways, van Luik, board members and others conceded that currently the evidence for building a repository at Yucca Mountain is thin.

Scientists still don't know what happens over time to Yucca's rock when heated as it would be by radioactive waste buried inside. Nor do they know where the small amount of ground water that flows through the mountain goes and whether water deep within the mountain could rise to the repository's level. Ground water poses a danger of corroding containers holding the radioactive waste. The DOE will have to prove to the Nuclear Regulatory Commission that radiation will not escape in ground water or the air for 10,000 years.

If a repository is built, the DOE wants Congress to fund studies for up to 125 years to monitor the buried wastes. Whether Congress provides that money is a great concern, van Luik said.

No one knows what the final design of a Yucca repository would look like, since studies still have not identified all of the potential problems. "There is nothing simple about this process and just because we come in with the right number in the equation doesn't mean a repository will get a license," van Luik said. The DOE expects to apply for a license as early as 2003; the earliest the repository could open is 2010.

The DOE presented little more than sketches of the enormous gaps scientists face in explaining how Yucca will keep radiation from commercial reactor and nuclear weapons wastes away from people and the environment.

What will it take for the DOE, regulators or Congress to say no to a Yucca repository, wondered Judy Treichel, director of the Nuclear Waste Task Force, a citizen-based information clearinghouse. No answer was offered. Many Southern Nevada residents are frustrated by the lack of answers, believing the repository will be built regardless of the science because there are no alternatives, she said.

"What is it that will make you say no?" Treichel said. "We always seem to be moving closer to it -- to saying yes."

In fact, the DOE next week will hear testimony on its bid to reject specific guidelines for approving a Yucca repository that were set in 1987. DOE officials instead want to be able to judge the mountain's suitability on a computer model that considers of the factors.

Jared Cohon, review board chairman, voiced the same concern after listening to the morning's presentations.

"I'm troubled and somewhat surprised at the lack of enthusiasm for quantifying uncertainty in the performance of the repository," Cohon said.

Two experts who measure risk from hazardous activities urged the DOE to put detailed information into its plan, which scientists expect to unveil in November.

Daniele Veneziano of the Massachusetts Institute of Technology urged the DOE to quit guessing and tell the public how a Yucca repository might behave over time.