WASHINGTON — When Congress targeted Nevada as the nation's nuclear waste dumping ground, the state didn't have the political power to say no.

Twenty years later, the most ardent foe of the Yucca Mountain nuclear waste dump is about to become Senate majority leader. Nevada Democratic Sen. Harry Reid's new job, which gives him control over what legislation reaches the Senate floor, could deal a crippling blow to the already stumbling project.

Among Reid's first acts after this month's election was to convene a conference call with home-state reporters to declare Yucca Mountain "dead right now."

"It sure is different now than when I came (to the Senate) in 1986," the senator observed.

The dump 90 miles northwest of Las Vegas is planned as the first national repository for radioactive waste. It's supposed to hold 77,000 tons of the material — from commercial power plants reactors and defense sites across the nation — for thousands of years. About 50,000 tons of the waste is now stored in temporary sites at 65 power plants in 31 states. Reid would leave all of it in place.

Originally targeted to open in 1998, Yucca Mountain has been repeatedly set back by lawsuits, money shortfalls and scientific controversies. The Energy Department's best-case opening date is now 2017.

The effort to create a national storage site has already cost about $9 billion, $6.5 billion of which has been spent on Yucca. Four years ago, the Energy Department estimated the project would cost $58 billion to build and operate for the first 100 years. New cost projections are being worked up, and they are expected to total more than $70 billion.

The department proposed legislation earlier this year meant to fix problems with the dump, which is a mounting liability to taxpayers because the government was contractually obligated to take nuclear waste off utilities' hands starting in 1998. Energy Department officials say at least one legislative change — formally withdrawing land around the dump site — is needed before construction can begin.

Reid, however, pledged after the Nov. 7 election that not only will no bill to help Yucca Mountain reach the Senate floor under his leadership, funding for the project also will dry up quickly. Annual spending on the dump that has ranged between $450 million and $550 million in recent years "will be cut back significantly, that will be for sure," he vowed.

Reid said he couldn't single-handedly kill the dump outright, something that would require a vote of Congress and approval by President Bush. But he added: "There's not much to kill."