WASHINGTON -- A proposal to expand the capacity of Yucca Mountain drew support from some lawmakers on Thursday as a way for the government to "buy time" while researching long-range recycling methods for nuclear waste.

"Such a move is essential to justify developing a reprocessing program," said Rep. Mike Honda, D-Calif., at a House science subcommittee hearing that discussed the Global Nuclear Energy Partnership, or GNEP, the Bush administration's nuclear fuel recycling strategy.

Honda was echoed by the panel chairman, Rep. Judy Biggert, R-Ill. Biggert said lifting a 70,000 metric ton waste cap that was set by law for Yucca Mountain "certainly buys us some time" to pursue reprocessing in the coming years.

The reprocessing plan has received mixed reviews among experts and on Capitol Hill. Experts assembled by the science panel Thursday applauded the concept, but said the costs and schedules are too ambitious.

"The goals and time lines advanced under the major portion of GNEP are unrealistic," said noted physicist Richard Garwin, a government consultant on technology and arms control.

A plan to expand Yucca Mountain is one feature in a bill announced this week by the Energy Department. It would remove a 70,000 metric ton cap set by law of how much nuclear waste could be stored within tunnels at the site 100 miles northwest of Las Vegas.

Besides being tied to the administration's waste reprocessing strategy, lifting the repository capacity has been sought by nuclear industry officials concerned that Yucca Mountain will be essentially filled by the time it is opened.

Already 55,000 metric tons are in storage at power plants and government reservations, the Energy Department reports.

A 2002 environmental impact study for Yucca Mountain analyzed placing up to 120,000 metric tons of waste into the mountain. According to the Nuclear Energy Institute, other DOE and independent studies have suggested the physical capacity could be two to four times that amount.

Repository expansion is only one element of the measure.

Other provisions broaden federal authority to obtain water and manage environmental and transportation matters.

It also shortens part of the NRC licensing process, and would allow DOE to begin constructing a Nevada railroad and certain buildings and physical features at the site soon after it submits a license plan to the Nuclear Regulatory Commission, possibly in 2008.

Nevada officials who oppose the Yucca project say the bill mounts an assault on state powers and will force larger amounts of radioactive material into the state.

Sen. John Ensign, R-Nev., said Thursday the bill could have been even worse.

Ensign said plans for interim waste storage that could have sent nuclear materials to Yucca Mountain even sooner were deleted from the bill only after he complained to White House chief of staff Andrew Card, and his successor Josh Bolten, in the past few weeks.

Meanwhile Thursday, other machinery on Capitol Hill began turning on the Yucca Mountain bill.

Sens. Pete Domenici, R-N.M., and James Inhofe, R-Okla., who lead energy-related committees, announced they were introducing the legislation in the Senate.

In the House, energy committee chairman Joe Barton, R-Texas, said he still was looking at the Bush administration bill.