WASHINGTON -- Long-range prospects for a nuclear waste repository at Yucca Mountain are clouded because there is no fix in sight for budget shortfalls that are plaguing the Nevada program, an Energy Department official said recently.

Ward Sproat, director of the Office of Civilian Radioactive Waste Management, said DOE is poised to meet a key licensing milestone by the end of the summer after budget cuts forced the latest in a series of retoolings.

But Sproat said the department has abandoned its "best achievable" goal of having a repository opened by 2017. Now, he said, DOE is reluctant to set a new target.

"A firm date cannot be set until the funding issue is resolved," Sproat said in a speech to the National Association of Regulatory Utility Commissioners, the organization of state public service officials.

Sproat urged the state officials to step up lobbying for Congress to pass a bill that would loosen the strings on the fund earmarked to pay for the repository.

Ratepayers for nuclear utilities are charged a fraction of a penny per kilowatt hour of electricity they consume, a rate that has built the fund to a $21 billion balance.

At some point, more than $1 billion will be needed annually for construction, DOE officials have said. But budget caps in Congress, plus the efforts of repository opponents like Sen. Harry Reid, D-Nev., have limited annual payouts to around $400 million.

"Until we get this issue fixed I can't, nor can anyone else, tell you with any degree of certainty when the repository is going to open," he said. "This is the single biggest issue we as a country need to address so this repository can go forward."

At $400 million a year, "We are never, ever going to build this repository with that kind of cash flow funding -- it just ain't going to happen," Sproat said.

The longer a repository goes unopened, the more taxpayers will pay to utilities who have sued the Department of Energy for delays, Sproat said.

If Yucca were to open by 2017, the liability would total an estimated $7 billion, he said. A 2020 opening would cost $11 billion in legal settlements and judgments.

Sproat said those numbers are getting the attention of lawmakers.

"We are talking big bucks," he said. "It is one of the levers that gets people interested and gets them to understand we just can't leave things the way they are."

Sproat said DOE plans to file a repository license application "sometime this summer" with the Nuclear Regulatory Commission.

Spending limits engineered by Reid in this year's budget caused DOE to push back a June 30 target.