A federal judge granted the order Tuesday to vacate a judgement favoring environmentalists in a plutonium pit lawsuit and stop the case from going to an appeals court.

The defendants, the Department of Energy and its semiautonomous National Nuclear Security Administration (NNSA), asked district judge Mary Geiger Lewis to vacate her Sept. 30 judgement validating the plaintiffs’ complaint that the federal government “violated the National Environmental Policy Act (‘NEPA’)” by failing to review the environmental effects of making plutonium pits in two states, a Wednesday court filing shows.

Lewis granted the motion to vacate the judgement on Nov. 26, about a week after the defendants made it.

After the judgement in the U.S. District Court for South Carolina, Aiken, Lewis ordered the antinuclear plaintiffs and the federal defendants to figure out how NNSA can conduct both a meaningful environmental review and continue development of the South Carolina pit plant. After many extensions, the parties have until Dec. 12 to figure out how to do that. 

“Given that this case is on-going with remedy proceedings underway,” the federal government wrote in its motion to vacate, “and to ensure that the time to appeal has not yet begun to run, Federal Defendants respectfully request that the Judgment be vacated until the Court’s proceedings are final to prevent any uncertainty as to the timely filing of a Notice of Appeal.”

The plaintiff antinuclear groups filed a lawsuit in 2021 saying they wanted the NNSA to stop development of a planned plutonium pit factory at the Savannah River Site in Aiken, S.C., while the agency reviewed the environmental effects of its plan to make plutonium pits both there and at the Los Alamos National Laboratory in New Mexico. 

NNSA said holding up the Savannah River plant for another environmental review could delay production of pits in South Carolina by five years. NNSA now estimates that the plant will come online in 2032 or so.

A spokesperson for the U.S. attorney’s office said the Dec. 12 deadline for negotiations remained in place but otherwise declined to comment on the case. 

NNSA had argued that it did not need to do another program-wide review of plutonium pit production because it had already done one in 2008. The agency believed it completed its environmental due diligence in 2020 by supplementing the 2008 review with new analyses specific to Los Alamos and Savannah River.

Lewis disagreed.