The federal government yesterday approved a $3.1 billion plan by a private corporation to store tens of thousands of tons of highly radioactive nuclear waste on a Native American reservation in Utah, potentially removing a major obstacle to the nuclear industry's ambitions for renewed growth.

The move paves the way for the industry to circumvent a lengthy political stalemate over a proposed public nuclear waste storage facility at Yucca Mountain in Nevada and could rid dozens of overcrowded nuclear plants around the country of the need to store radioactive products that will remain dangerous for centuries.

Environmental groups and Utah officials said the decision raised the risk of an accident or a deliberate attack, and promised to challenge it in court. One faction of the deeply divided Skull Valley Band of Goshutes, which has agreed to host the facility, said the nuclear waste would debase sacred ground and destroy tribal culture.

The decision by the Nuclear Regulatory Commission to grant a license for the facility cemented a pact made nearly a decade ago between strange bedfellows: utility behemoths that wanted to get tons of radioactive waste off their hands and an obscure Native American tribe that was willing to offer its land in exchange for a still-undisclosed sum of money.

While public waste storage plans such as Yucca Mountain have been plagued by political maneuvering and not-in-my-back yard fights in Congress, Private Fuel Storage, the company that will build the new facility, successfully argued that its agreement was between a private corporation and a sovereign tribe and therefore not subject to the same degree of public review. Environmental groups and the state of Utah have tried repeatedly to intervene but have failed.

"Are you better off having a single site that can be looked after or 72 individual sites, some of which may be on the banks of a great lake or a river or upstream of a major city?" asked Jay Silberg, a Washington lawyer for Private Fuel Storage.

The terms of the company's arrangement with the Skull Valley Band of Goshute Indians have not been disclosed. Silberg said that was proprietary business information.

"If I were storing canisters of rock for someone else, you would not necessarily have the right to get that information," he said. Storing nuclear waste is no different except when it comes to safety issues, he added, and those have involved lengthy public deliberations and thousands of pages of documents.

Silberg said the site eventually could hold as much as 40,000 tons of spent fuel, the radioactive byproduct of nuclear power plants. The waste would sit in powerfully built casks on concrete pads, similar to the way it currently is stored at many of the nation's 103 plants. The earliest the site could become operational would be 2007, Silberg said.

David McIntyre, an NRC spokesman, estimated that plants around the country have about 52,000 tons of spent fuel, with about 10,000 of those tons already sealed in casks.

Opponents immediately signaled that the fight was not over. Utah Gov. Jon Huntsman Jr. (R) promised a court challenge. Sen. Orrin G. Hatch (R-Utah) said the plan would be "dead on arrival." Utah has no nuclear plants of its own and holds no nuclear waste.

Denise Chancellor, Utah's assistant attorney general, who has made the legal case against the facility, said there was a serious risk that an F-16 fighter from the nearby Hill Air Force Base could crash at the site, with catastrophic consequences. She questioned the objectivity of NRC commissioners in ordering that a license be granted.

"They are a regulator but also a promoter of nuclear energy," she said. "Given that dual role, from this side of the table it looks like there is a bias."

The Skull Valley Goshutes are one of several tribes that the nuclear industry sought out to store the waste. The tribe has only about 130 members, including about 85 adults. Tribal chairman Leon Bear long has been a proponent of the facility, but the tribe is riven by divisions. Bear has traded accusations with other factions, and both he and a leader of a faction opposed to the nuclear facility have been found to have misappropriated tribal funds.

Bear did not return a call yesterday.

But Margene Bullcreek, another member of the tribe, accused Bear and the Bureau of Indian Affairs of exceeding their authority. Although the Private Fuel Storage facility is considered an interim facility, Bullcreek said the continuing problems with the Yucca Mountain facility and the political difficulty of moving nuclear fuel a second time once it gets stored somewhere will make the tribal waste storage plan permanent.

"We believe in the sacredness of our water and our air and our environment," she said in a telephone interview yesterday. "The NRC is blind. They have no heart, no feelings. It doesn't matter if it's a reservation."

Dave Lochbaum, of the Union of Concerned Scientists, a group that advocates for nuclear safety, said the private facility did not make sense.

"If the interim storage site is not at the final repository, it means you are moving the spent fuel twice, which means the cost goes up and the safety goes down," he said. "It sounds unsafe and uneconomical."

But Steve Kerekes, a spokesman at the Nuclear Energy Institute, called such fears "hollow." The country has a long track record of moving nuclear waste safely, he said.

Kerekes said the federal government had failed to honor its word to build a permanent facility, which is why member companies of the nuclear industry umbrella trade group had sought a solution of their own.

Referring to the safety concerns of advocacy groups, he said, "If they are so concerned about that, put pressure on the government to meet its obligation."