WASHINGTON — Lawmakers agreed Monday to cut 2006 spending for Yucca Mountain well below past-year levels and President Bush's budget request, reflecting the faltering prospects for locating the nation's nuclear waste dump in the Nevada desert.

House and Senate negotiators also ditched a House plan to supplement Yucca Mountain with interim storage sites for nuclear waste, settling instead on spending $50 million to promote recycling spent nuclear fuel.

In finishing work on a $30.5 billion bill to fund energy and water projects, lawmakers agreed to spend $450 million in 2006 on Yucca Mountain, the planned underground repository for 77,000 tons of the nation's most radioactive nuclear waste.

The project's budget was $577 million in each of the past two years, and Bush asked for $650 million for the dump in his 2006 budget request.

The final figure also was less than the House and the Senate agreed to separately earlier this year, but lawmakers and aides said delays on the project kept the number low.

"No matter what side of Yucca you're on, the truth of the matter is Yucca is . . . not on the schedule that even was predicted the last time. It's behind schedule," said Sen. Pete Domenici, R-N.M., chairman of the Senate Appropriations Committee's energy and water subcommittee.

"We think that this will keep what should be done on schedule," he told reporters.

Two years ago, the Energy Department projected needing $1.2 billion for Yucca Mountain in 2006. That was when officials were hoping to quickly submit a license application to the Nuclear Regulatory Commission and open the dump by 2010.

Since then, a series of setbacks — including a required rewrite of radiation safety standards — have slowed the project.

Now it's not clear when the license application will be submitted, and the projected opening date has slipped to 2012, at the earliest.

"While this funding decision may force us to go at a slower pace, it will not deter us from our principles of using sound science to develop a high-quality license application and a disposal facility that is safe and reliable to operate," Energy Department spokesman Craig Stevens said.

Sen. Harry Reid, D-Nev., who has opposed locating the dump 90 miles northwest of Las Vegas, said the project is "fraught with inadequate science and insidious mismanagement."

"The project is never going to open and each year we grow closer to killing it," he said.

Lawmakers deleted a House proposal to spend $10 million for the Energy Department to produce a plan for temporary above-ground storage for spent reactor fuel from commercial nuclear power plants.

Instead the bill contains $50 million for spent fuel recycling, including $20 million for states or localities to compete to host a recycling facility and $30 million for research and other work.

The bill is expected to be approved later this week by the full House and Senate.