Washington (CNN) -- An Energy Department official Wednesday defended the Obama administration's decision to pull the plug on a long-planned Nevada repository for nuclear waste in the face of questions from Congress about whether the move was legal.
"The department is acting responsibly in terminating the Yucca Mountain project," Peter Lyons, the assistant energy secretary for nuclear power, told a House subcommittee. "We can and we should do better than the Yucca Mountain project."
Congress designated Yucca Mountain in 1987 as the storage facility for U.S. nuclear waste, some of which can remain hazardous for centuries. The U.S. government has spent nearly $100 billion to build the facility, which was designed to store tens of thousands of tons of radioactive waste from civilian and military nuclear facilities.
The Energy Department announced in 2010 it was dropping its request for an operating license for the facility, arguing that years of intense opposition made it unworkable. Lyons told the House Energy and Commerce subcommittee on the environment and the economy that the United States needs "a new option with a higher certainty of success."
But picking a new site for the national nuclear waste dump "would likely take decades and cost billions of dollars," according to a newly released report from congressional auditors. And Lyons came in for sharp questions from Republicans, who argued that the attempt to kill Yucca Mountain violated the federal law that declared it the nation's nuclear waste dump.
"It is the law, period," said Rep. Doc Hastings, R-Washington, who appeared as a witness before the panel. "Now, some may disagree with the law, but it is the law."
Hastings' district includes the badly contaminated Hanford nuclear weapons plant, currently the subject of a multibillion-dollar, multidecade cleanup effort. He called the decision "purely political," noting that the Energy Department has been unable to cite any technical reason for ending the Yucca Mountain project.
"Changing the goalposts at halftime will unnecessarily add risk to the project and has the potential to waste limited cleanup dollars that are already difficult to secure," he said.
The site, about 100 miles northwest of Las Vegas, has been widely opposed for decades. Among its chief opponents has been Nevada Democratic Sen. Harry Reid, now Senate majority leader.
Rep. Shelley Berkley, a Las Vegas-area Democrat, told the subcommittee that polling shows more than three-quarters of Nevadans oppose Yucca Mountain.
"We don't want our home turned into a nuclear garbage dump, and we oppose more wasteful spending on a $100 billion dinosaur in the Nevada desert that should have gone extinct years ago," Berkley said.
However, Gary Hollis, the chairman of Nevada's Nye County Commission, said the project has the support of its surrounding community.
"All five Nye County commissioners expressed their support for Yucca Mountain, and all were elected or re-elected by our citizens," he said.
And even some Democrats on the committee questioned what would be done with the thousands of tons of wastes now in temporary storage around the country without Yucca Mountain, which had been scheduled to open in 2020.
"This question was going on when I was the chairman of this committee. And as a matter of fact, it was going on when I was a young member of this body," said Rep. John Dingell, D-Michigan, who was first elected in 1955. "When is it I can look forward to being young enough that I'm going to get an answer on these questions?"
The Energy Department has established a blue-ribbon commission to look into new plans for storing nuclear waste. Lyon disputed the auditors' findings that replacing Yucca Mountain would take decades, arguing that other alternatives could be found and put into service before the repository's expected completion.