Yucca dump draws criticism from international experts

Tuesday, Nov. 13, 2001 | 9:27 a.m.

International review panels have criticized a proposed nuclear waste repository at Yucca Mountain as Energy Secretary Spencer Abraham prepares to recommend the site as the nation's nuclear waste repository.

The scientists, including representatives of the Nuclear Regulatory Commission, are concerned that the Department of Energy lacks sufficient information to prove the site safe to house the nation's high-level nuclear waste for at least 10,000 years.

International experts have been critical of the DOE's study of the saturated zone, where water could carry radiation away from the proposed repository, an article in this month's Physics Today said.

Abe Van Luik, a senior DOE policy adviser, said the Energy Department thought that the saturated zone beneath the proposed repository, where any radioactive contamination would leave the site, was well understood. But the reviewing scientists were "critical" of the DOE's work, he said.

When scientists first began studying Yucca Mountain, 90 miles northwest of Las Vegas, the mountain's volcanic ash was expected to keep most of the radiation from the environment, the reports say. But as DOE studies revealed more ground water than expected, more earthquake faults and the threat of volcanic activity, man-made barriers, such as waste containers and underground metal drip shields, became the major defenses.

Unanswered questions about how the metal used for disposal containers would react to ground water when it is combined with chemicals heated by the waste inside the repository troubled the scientists. Water and heat could corrode the stainless steel containers, they said.

The experts also said the DOE is relying too heavily on the man-made barriers.

"A large amount of experimental and analytical work is needed on the long-term performance of waste package materials to enhance the technical basis and to increase confidence in long-term performance projections," an international scientific team reviewing proposed waste containers said.

The reviewers said they were concerned that DOE has neither the time nor the money to answer serious questions regarding the strength of the containers.

Although the DOE's approach to evaluate Yucca Mountain's performance -- the Total System Performance Assessment -- is adequate, reviewers said the Energy Department needs to convince Nuclear Regulatory Commission staff members that buried waste will not leak from corroded containers and release radiation into the ground water.

The NRC must license Yucca Mountain before the DOE can build a repository. The NRC's scientific consultants have expressed concern about the possibility of a volcano erupting through buried waste at Yucca Mountain, as well as how fast ground water moving through the mountain would release radiation into the environment.