The lawmakers, 67 of whom are Republicans, told Chu in a letter that they "are deeply troubled" that the US Department of Energy is continuing to move forward with its plan to terminate the Yucca Mountain project despite recent actions by the US Court of Appeals for the District of Columbia Circuit and a US Nuclear Regulatory Commission Atomic Safety and Licensing Board.

The court has established an expedited schedule to hear arguments in a lawsuit over DOE's termination of the repository project, and the ASLB in late June said the agency does not have the authority to unilaterally withdraw its repository license application.

All 91 lawmakers who signed the letter represent states that have nuclear power or DOE nuclear facilities with high-level defense waste stored on site.

Termination of the Yucca Mountain project would mean that power reactor spent fuel and the department's HLW would remain at its current sites, perhaps for decades, until there is a new path forward for the waste.

The site is roughly 95 miles outside Las Vegas. If licensed, Yucca Mountain would be the site of a deep-geologic repository that would be used to dispose of 70,000 metric tons of spent fuel and HLW. By law, the 70,000 mt cap would be lifted once a second repository is operational in the US.

"The Nuclear Waste Policy Act designated Yucca Mountain as the only candidate site for the national repository," lawmakers said. "Congressional intent is clear--Congress has voted several times to retain Yucca Mountain as the national repository."

Lawmakers asked that DOE recognize "the spirit of the law" and "halt all efforts to reprogram funds or terminate contracts related to Yucca Mountain."

They said they are "deeply disappointed that DOE has overstepped its bounds and has ignored congressional intent without peer review or proper scientific documentation in its actions regarding Yucca Mountain."

--Elaine Hiruo, elaine_hiruo@platts.com