Several members of Congress are heading to the mothballed site of a proposed radioactive waste dump in the Nevada desert amid new talk about a decades-old problem—where to dispose of spent nuclear fuel stored at commercial reactors around the U.S.

A congressional tour of Yucca Mountain on Thursday is being led by U.S. Rep. John Shimkus, Republican chairman of the House Environment and the Economy Subcommittee and a supporter of plans to entomb the nation's most radioactive waste 90 miles northwest of Las Vegas.

Shimkus said the trip did not signal a resumption of the Yucca Mountain program because Congress never stopped it.

"You can't restart something that hasn't officially ended," Shimkus said.

The trip comes with momentum building toward restarting the Yucca Mountain project, weeks after U.S. Sen. Harry Reid, a steadfast opponent of burying nuclear waste in Nevada, announced he will retire after 2016. Reid has repeatedly pronounced the project dead while working with President Barack Obama to strangle funding for it. But Obama leaves office next year, too.

Shimkus is from Illinois, a state with several of the country's 109 nuclear power reactors.

"Our nation desperately needs to advance our nuclear waste strategy and Yucca Mountain is a part of the solution," Shimkus said in a statement.

Joining the tour will be Nevada's newest Congress member, GOP Rep. Cresent Hardy—a dissenting voice in an otherwise united front of Nevada elected officials opposed to accepting highly radioactive waste from other states.

In a recent newspaper opinion column, Hardy signaled a willingness to listen to offers for economic support for Nevada schools, new roads and the possibility of a larger share of water from the drought-stricken Colorado River. The visit will be a first for Hardy, whose district includes Yucca Mountain.

Shimkus has called for Congress to fulfill a 1982 promise to spend money collected from commercial utilities to permanently store spent nuclear fuel that will remain dangerously radioactive for more than 10,000 years.

"Seeing the site in person really adds some perspective to the debate as you appreciate just how remote the location is and just how much time and money has been poured into the project," Shimkus said.

Estimates are that $15 billion was spent drilling a 5-mile U-shaped tunnel and studying whether 77,000 tons of hazardous material could remain safe and dry in casks wheeled on rails into a honeycomb of tunnels 1,000 feet underground. Some estimates put the final cost at $100 billion.

Nevada has opposed the project for more than 30 years.

"In my view, it's an issue of public health and safety—and that's not negotiable," said Richard Bryan, a Democrat who was governor when Congress in 1987 made the state the only one under consideration for the site. Bryan fought the project as a U.S. senator and today chairs the Nevada Commission on Nuclear Projects.

Nevada has spent almost $46 million opposing the project since 2001, said Robert Halstead, the agency chief who heads the state's efforts. The state also holds crucial water rights the federal government would need to proceed.

Also on the trip will be Republican Reps. Mark Amodei of Nevada, Bob Latta of Ohio, Dan Newhouse of Washington, and Democratic Rep. Jerry McNerney of California.

"When they see how far it is, and how isolated it is, that'll be helpful," said Dan Schinhofen, a commissioner in Nye County, home to Yucca Mountain. Schinhofen foresees thousands of jobs and economic development if the project is restarted and licensed.

Nevada Republican U.S. Sen. Dean Heller criticized the excursion as a "disingenuous, political sideshow" and said if the trip organizers were interested in fact-finding they would have invited experts from the state to participate.

"I am disappointed this golden opportunity was squandered into nothing more than a poorly disguised gimmick," he said.

"Nevadans have made their intentions clear, they simply do not want nuclear waste stored at Yucca. No amount of political pomp and circumstance will change that."

Congress in 2002 approved the specific site but cut off funding after Reid became Senate majority leader in 2007. Under Obama, the Energy Department shuttered the project and the Nuclear Regulatory Commission halted the licensing process.

A federal court in 2013 ordered the commission to resume licensing, and agency staff in January released a report that appeared to provide wiggle room for adopting rules to open the repository.