Bennett's reasoning echoes arguments made for years by opponents of PFS, including Gov. Jon Huntsman Jr.'s office and the offices of the two governors who preceded him.

The simple fact of the matter, Bennett said, is that the volumes of nuclear waste being generated by a resurgent nuclear energy industry means PFS will become permanent even if Yucca Mountain opens.

"Yucca Mountain is not going to become the single repository for nuclear waste," he said, referring to PFS as the alternative repository.

News of Bennett pulling his support was welcomed by groups against having high-level nuclear waste in both Utah and Nevada. They have opposed storage for the same reasons that Bennett cited in his Tuesday speech.

The governor said in a statement that Bennett's new position "represents a highly rational approach and a long-term fix to a problem that promises to affect us short term. I've had the opportunity to discuss this issue with Sen. Reid on several occasions and agree with his conclusions," Huntsman said.

Also welcoming Bennett's decision was Healthy Environment Alliance of Utah, which for years has fought both the shipping of high-level nuclear waste and the establishment of a repository in either state.

"We're glad to see the leadership Sen. Bennett is showing, to work with our neighbors in the West and force the generators of this waste to share the responsibility of managing it," said Jason Groenewold, director of HEAL, which is based in Salt Lake City.

Groenewold said he hopes Hatch will soon join in "the call for not dumping nuclear waste on the Western states." The material should be stored where it is generated until the United States develops a reasonable long-term solution, he said, adding that he believes Bennett's speech was needed to help solidify that effort.

"No one was going to come to Utah's aid in this fight to stop nuclear waste storage in Utah unless we reached out and created alliances" with others with a common interest, Groenewold said. "And Sen. Bennett's actions indicate his willingness to extend an olive branch to those who we've alienated in the past."

Rep. Jim Matheson, D-Utah, and a longtime opponent of Yucca Mountain, added that he "recognized that Utah and Nevada should be united against the arrogance of the East Coast dumping its waste on the West. We still have never addressed the transportation risks, whether on the roads or rails to Skull Valley or Yucca Mountain. That is why this lethal cargo should stay where it is until an acceptable disposal solution can be found."