Agency Is Seen as Unfazed on Atom Waste

WASHINGTON, June 11 - The plan to bury nuclear waste at Yucca Mountain may need major revisions, but the Energy Department is pressing ahead with the project, according to some independent scientists appointed by President Bush to review the project.
The Yucca repository, near Las Vegas, is years behind schedule and the Energy Department is facing financial penalties for its failure to begin accepting waste from civilian reactor operators in 1998, as mandated under contracts the department signed with utility companies two decades ago. Many of those reactor operators are incurring substantial extra costs as they run out of storage space.
The Energy Department acknowledges some uncertainty about the design, but is promising to apply by the end of this year for a license from the Nuclear Regulatory Commission to build the repository.
Supporters argue that if the repository turned out not to work as expected during its first few decades of operation, physical changes could be made and that, for now, the plan should proceed.
But the design concept is vulnerable to corrosion, according to the Nuclear Waste Technical Review Board, a panel of scientists appointed to review work of the Energy Department.
Last year the board warned that humidity in Yucca Mountain's tunnels could dissolve salt from the rock there, which could then corrode "drip shields," metal tents made of a sophisticated alloy that are meant to keep the containers that would hold the waste dry.
The idea that the drip shields will protect the containers "is based mostly on assumptions that could be unrealistic and overly optimistic," the board said, and the Energy Department's predictions of how the drip shields would perform for thousands of years "are speculative."