The safety of the American people, not political pressure from the energy industry, should be the overriding concern

Senate Majority Leader Tom Daschle

The site - Yucca Mountain some 150 kilometres (90 miles) from Las Vegas - was singled out 15 years ago as America's potential nuclear waste repository.

Under government plans, more than 70,000 metric tons of radioactive material from US nuclear power plants would be stored deep inside the mountain for about 10,000 years.

Debate

US Energy Secretary Spencer Abraham, who formally recommended Yucca Mountain to President George W Bush, called the site "scientifically sound and suitable".

He said a single nuclear waste site was crucial for national security since the 11 September attacks on New York and Washington, which raised concern about guarding America's radioactive material.

Nuclear waste from the United States' 103 nuclear power plants is growing at the rate of 2,000 tons a year and is currently warehoused at reactor sites in 31 US states.

"There are compelling national interests that require us to complete the siting process and move forward with the development of a repository, as Congress mandated almost 20 years ago," Mr Abraham wrote in a letter to Nevada's Republican State Governor Kenny Guinn.

US nuclear waste grows at a rate of 2,000 tons per year

But Nevada officials reacted with anger to the announcement and vowed to fight the plans - if necessary in court.

"This decision stinks," said Governor Guinn.

The Nevada authorities argue that despite years of intense research, experts have not been able to show adequately that the public can be protected from future radiation.

Environmental groups and Nevada lawmakers have also expressed concern over future volcanic activity near the site, possible earthquakes and underground water movements.

But the government says these issues have either been resolved in previous studies or can be dealt with during the licensing process for the design of the facility.

Battle in Congress

Even if Yucca Mountain is finally approved, no waste would be shipped to the site until 2010 at the earliest.

And although the energy department endorsement is a key step, the Yucca Mountain project still faces several obstacles before construction can begin.

The next battleground is in Congress where the Nevada congressional delegation is likely to get support from Senate Majority Leader Tom Daschle, who has described the government endorsement of the project as "unfortunate and premature".

"The safety of the American people, not political pressure from the energy industry, should be the overriding concern," Mr Daschle said in a statement.

Spencer Abraham says Yucca Mountain is safe

He added that scores of studies were still underway and until they are finished, the government should not choose a site.

Mr Daschle, a Democrat, is from South Dakota which, like Nevada, has no nuclear power plants.

Several Congressmen have welcomed the government plans and the nuclear industry has hailed them as a breakthrough.

Correspondents say some states with nuclear power plants are keen to ship radioactive waste outside their borders.

Since choosing the site in 1987, the federal government has spent more than $6 billion studying Yucca Mountain.

A tunnel has been dug into it where massive heaters have sought to simulate the high temperatures that can be expected from the highly radioactive wastes once they are put in a labyrinth of underground bunkers.