DOE faces unresolved Yucca issues

Benjamin Grove

Thursday, May 10, 2001 | 11:05 a.m.

WASHINGTON -- Four critical issues under study at Yucca Mountain remain unresolved as the Energy Department this year finalizes plans to recommend the site as the nation's nuclear waste dump.

That's the opinion of the independent U.S. Nuclear Waste Technical Review Board, Chairman Jared Cohon said Wednesday.

Cohon said DOE scientists have these important tasks left unfinished:

Cohon said observers often ask: Should the DOE recommend Yucca Mountain before it answers these questions?

Policymakers, not scientists who make up the board, should make that call, Cohon said.

But with more answers in hand, "the more likely it is that the technical basis for the decision will be strengthened," Cohon said in a written statement.

The 11-member board was created by Congress in 1987, the year lawmakers designated Yucca Mountain, 90 miles northwest of Las Vegas, as the burial ground for the nation's nuclear waste.

The board answers to Congress and reports to the energy secretary about the scientific validity of DOE studies at Yucca.

The board discussed a number of scientific issues pending at Yucca at a regular meeting in Arlington, Va.

Among the controversial debates that percolated: Whether ancient paths of hot water inside the mountain's cracks constituted a Yucca "show stopper."

A Russian geologist and contractor for the state of Nevada said his research shows water triggered by an earthquake bubbled up from beneath Yucca and into the mountain. That kind of water movement could happen again, which would be dangerous if Yucca was full of radioactive waste, Yuri Dublyansky said.

The Yucca project "is not doable," Dublyansky said in an interview.

But a number of other scientists disagree.

Several officials from the U.S. Geological Survey said evidence of ancient water trapped inside Yucca crevices likely trickled down from the surface, rather than bubbling up from the earth.

The water could have been heated by a giant magma mass inside the Earth millions of years ago, Joe Whelan of USGS said.

"If we are correct, and we believe we are, there are no (hydrology) show-stoppers (at Yucca)," Whelan said.

UNLV scientist Jean Cline, who led a widely respected two-year study of water movement at Yucca, agreed.

Cline reasserted her findings released earlier this year: Hot water moved through Yucca, but it was at least 1.9 million, possibly 5.7 million years ago. That's too long ago to suggest it would happen again, she said in an interview.

"We don't see this as being a significant issue," she said.

The DOE sides with Cline, the USGS and others who agree ancient water paths are not problematic, including geochemical expert Robert Bodnar of Virginia Polytechnical Institute, who acted as Cline's team consultant, one DOE official said.

"Unanimity (of opinion) is not required here," William Boyle, a senior DOE adviser, said in an interview.

"It will be up to us to make a convincing argument to the NRC, and explain our position. We will say, 'Here is what we think. Here is what (Dublyansky) thinks.' "

Also at issue Wednesday was the metal waste container that would store the bundles of spent uranium fuel rods for thousands of years. Scientists at Lawrence Livermore National Laboratory are studying how the proposed metal, an alloy called C-22, would stand up to high temperature, rock falls, drips, dust and other disturbances.

A container wall of C-22 alloy 20 millimeters thick could last an estimated 30,000 to 1 million years, said Narasi Sridhar of the Center for Nuclear Waste Regulatory Analysis, a federally funded center sponsored by the Nuclear Regulatory Commission.

Other scientists have said the first container failure would occur around 10,000 years, although one board member said it was "hopeless" to know how long the container would last, given just a few years of research.

The meeting opened with a review of some of the other scientific questions, including whether radioactive chlorine found inside Yucca Mountain along earthquake faults came from 1950s above-ground nuclear bomb tests in the Pacific. That would indicate rainwater had moved down through the mountain in just 50 years.

Other unresolved issues: How the repository should be ventilated; how falling rocks inside the repository could damage waste canisters and drip shields; and whether water found inside the Yucca testing areas "seeped" inside or was condensation.

One anti-nuclear activist spoke, saying the general public is upset that many questions formally submitted during other hearings to the DOE have gone unanswered.

Kevin Kamps of the Nuclear Information and Resource Service, has traveled around the nation trying to draw attention to what NIRS considers the danger of hauling nuclear waste by truck and train cross-country to Nevada.

"It's important to say that the public sees this board as one of the last lines of defense on a very politically charged issue," Kamps said.

The board plans a public meeting in September in Las Vegas.