Updated

After two decades of study and fervent protests from Nevada, President Bush signed a bill Tuesday making Yucca Mountain the nation's central repository for nuclear waste.

"The successful completion of the Yucca Mountain project will ensure our nation has a safe and secure underground facility that will store nuclear waste in a manner that protects our environment and our citizens," White House spokesman Ari Fleischer said in a statement.

The project had been studied for more than 20 years, and Bush signed the measure with no fanfare. Reporters were not allowed to witness the bill-signing.

The House and Senate voted earlier this year to entomb thousands of tons of radioactive waste inside Yucca Mountain — in the desert some 90 miles northwest of Las Vegas.

Nevada's senators, who tried for months to rally their colleagues against the Yucca waste dump, argued that the issue was much broader than Nevada. They hoped concerns over thousands of waste shipments crossing 43 states would sway some lawmakers, but they were defeated.

Bush has long backed Yucca Mountain as a repository site, formally recommending it in February.

Nevada filed a formal protest — as was its right under a 1982 nuclear waste law — leaving it for Congress to make a final decision. The House approved it in May, the Senate this month.

The state has five lawsuits pending against the project, and the Energy Department must still get a license from the Nuclear Regulatory Commission. That process could take up to five years.

Even some Yucca supporters admit that plans to open the site by 2010 may be too optimistic.

Energy Secretary Spencer Abraham said he was convinced that 77,000 tons of waste destined for Yucca could be stored there safely for the tens of thousands of years that it will remain highly radioactive.

The Bush administration and other Yucca site supporters said leaving the radioactive garbage at 131 power plants and defense sites in 39 states would pose an even greater risk than hauling it to Nevada. And they said waste has been transported for years without radiation releases.

But critics, including Senate Majority Leader Tom Daschle, D-S.D., complained that there were still "far too many questions" about the Yucca site and transportation safety issues

Environmentalists dubbed the planned waste shipments "mobile Chernobyl" — a reference to the nuclear disaster in the former Soviet Union. They see a disaster in the making as the radioactive cargo moves past major cities, over bridges and through tunnels on its way to Nevada.

Abraham promised a transportation plan before the end of next year and said stringent safety requirements will provide an "effective first line of defense" against terrorist threats. "We've proven we can move it safely," he said after the Senate vote.