The U.S. Energy Department yesterday submitted an application seeking to build and operate the nation's first permanent repository for used nuclear fuel at Yucca Mountain in Nevada.

Edward F. Sproat, manager of the Yucca project, said that with funding and approvals, the underground facility could begin accepting waste from shutdown reactor sites and the nation's 104 operating reactors by 2020.

"For our part, today is a very big day," said Energy Secretary Samuel Bodman. "It will put this project, I believe, in a new frame of mind going forward."

The project, estimated to cost between $70 billion and $80 billion, has been delayed by funding problems, legal challenges, and allegations of falsified quality checks. The department initially agreed to take waste from owners of commercial nuclear power plants by 1998, and the owners sued the agency for failing to meet that deadline.

Yesterday's move forward is a "major milestone for the nation," said Steve Kraft, a senior director at the Nuclear Energy Institute.

The 17-volume application was filed with the Nuclear Regulatory Commission. "We are rolling up our sleeves and going to work," NRC spokesman David McIntyre said.

The application is subject to a 90-day review on whether it is complete, McIntyre said. The agency has three years to review the full application, and can notify Congress if it needs a fourth year.

More than 56,000 metric tons of waste is currently stored at 120 sites in 39 states, according to the department. Yucca Mountain could store 70,000 metric tons of waste at the site, 100 miles northwest of Las Vegas.

Opponents of the project, including Senate Majority Leader Harry Reid of Nevada, have vowed to prevent it from ever being built. Reid, a Democrat, has helped to cut congressional funding for the project in an effort to slow or stop its development.

Nevada Gov. Jim Gibbons, another opponent, said: "As long as I am governor, the state will continue to do everything it can to stop Yucca Mountain from becoming reality."

The application prepared for the NRC still lacks a final public radiation-exposure standard that establishes how protective the facility must be from radiation leakage. The EPA had issued a standard designed to be protective for 10,000 years.

But a federal court said it was inadequate and the agency must establish a standard shown to be protective for up to one million years, the time some of the isotopes in the waste will remain dangerous. The EPA has yet to produce that document. But energy officials did not think that would be a problem.

The NRC, which has three years to review the application, can accept it later as an amendment. The NRC's primary job will be to determine whether the repository's design will protect public health, safety and the environment for up to a million years.

Meanwhile, the Energy Department has asked Congress to expand the amount of waste that can be stored. More space for spent fuel will be needed if companies go forward with plans to build new reactors. The NRC, which oversees reactors as well as nuclear waste, is expecting applications for as many as 34 new reactor units by 2010.

This article contains information from the Associated Press.