EPA Proposes Exposure Limits for Yucca Mountain

The Environmental Protection Agency (search) is proposing new radiation exposure limits for a planned nuclear waste dump in Nevada, a revision aimed at protecting the public for as long as 1 million years, agency officials said Tuesday.

The proposed new standard is intended to satisfy a court decision a year ago that said the EPA's initial requirements were inadequate. The ruling threatened to cripple the project at Yucca Mountain (search), 90 miles northwest of Las Vegas, unless the EPA developed new rules.

The proposal was discussed by government officials speaking on condition of anonymity because the decision was being announced by the agency later Tuesday.

Yucca Mountain is planned as a national repository for spent commercial reactor fuel and high-level defense waste. The opening date has been repeatedly delayed and is now expected in 2012 or later.

The EPA proposal, which would become final after a public comment period, will establish a two-tier standard that limits the level of radiation exposure to the public from the waste dump -- one for a period of up to 10,000 years and another for well beyond that to as long as 1 million years, the officials told The Associated Press.

A federal appeals court in July, 2004, said that the EPA had violated the direction from Congress when it had earlier limited its exposure standards to 10,000 years. A National Academy of Sciences report had said such a standard should target the periods of greatest radiation levels from the waste, a period well beyond 10,000 years.

Under the revised standard, a person near the site must be exposed to no more than an additional 15 millirems of radiation over a year up until 10,000 years as a result of radiation leaking from the buried waste through groundwater or other sources, according to EPA officials.

After 10,000 years the standard requires that the maximum radiation from the dump be at a level that assures people living near the site will not received total radiation amounts exceeding the national average from natural background sources.

Average background radiation over a year nationwide is about 350 millirems a year.

The Yucca Mountain waste site is being designed to accept highly radioactive used reactor fuel from commercial nuclear power plants around the country as well as some defense waste. The government had hoped to open the underground site by 2010, but that timetable has slipped to 2012 or possibly later.

President Bush gave the project the go-ahead in 2002, despite strong opposition from Nevada officials. But the project has been plagued by a series of problems since then, from budget shortfalls to a demand by the court to rework the radiation standards.

Craig Stevens, a spokesman for the Energy Department, said the administration is firmly committed to pushing ahead with the Yucca project.

"This is a standard that we can certainly meet," said Stevens, when told of the EPA's two-tier approach.

The Energy Department hopes to submit a formal application for a license for Yucca Mountain with the Nuclear Regulatory Commission early next year, although Stevens said the department was not setting a date.

The NRC must issue both a construction and operating license for the site. Nevada officials have vowed to fight the project before the NRC.

The nuclear industry has pushed for a central repository for reactor waste, arguing that the government promised such a site be available. Currently there are some 50,000 tons of reactor waste -- in the form of spent fuel rods -- at commercial reactors in 31 states.