WASHINGTON -- Nevada's senators say White House environmental advisers were supposed to have completed a new Yucca Mountain analysis by now, and they are demanding to know where it is.

Federal law requires the White House Council of Environmental Quality to prepare impact studies to accompany proposed bills, the senators said.

So Sen.'s Harry Reid, D-Nev., and John Ensign, R-Nev., asked council Chairman James Connaughton in a letter Wednesday for the report on a Yucca Mountain bill that the Bush administration sent to Capitol Hill on April 5.

"The CEQ must provide this analysis to Congress," Ensign said.

The demand was viewed as a fresh shot across the bow of the Bush administration as the Nevada senators load new ammunition against the proposed nuclear waste repository.

Aides said the senators suspect a report has not been written. Reid and Ensign would plan to bring that up at a Yucca Mountain hearing set for next Thursday before the Senate Energy and Natural Resources Committee.

"CEQ's analysis is necessary for members of Congress and the public to understand the impact and parameters of the proposal," Reid and Ensign said in the letter.

A CEQ spokeswoman on Thursday declined to discuss the status of any Yucca Mountain report or to confirm whether one has been written. The spokeswoman would not say if the White House believes one was required or not.

"We will be responding to the senators' letter and we will share the response after the senators see it," spokeswoman Kristy Hellmer said.

The Senate committee is scheduled to examine a Bush administration bill that aims to clear away some of the obstacles that Energy Department officials say are holding up the repository project.

The measure would reclassify the Yucca Mountain fund so DOE can gain access to funds needed for construction.

It would withdraw the site 100 miles northwest of Las Vegas from public land status, and would lift a 70,000-metric-ton cap on how much nuclear waste can be placed inside the mountain.

The bill also would make it easier for DOE to claim water rights for the repository despite Nevada opposition. It also would expand the energy secretary's authority on nuclear waste transportation.