The Senate’s version of the 2019 National Defense Authorization Act, which could hit the floor for debate this week, is the third piece of federal legislation produced this year to block the Department of Energy’s plan to cancel the Mixed Oxide Fuel Fabrication Facility (MFFF).

The bill, approved by the Senate Armed Services Committee on May 24, includes an amendment from Sen. Lindsey Graham (R-S.C.) that would, for one year, prohibit DOE’s National Nuclear Security Administration (NNSA) from either closing the unfinished facility, or converting the building into a factory for fissile warhead cores called plutonium pits.

The Senate had not released the text of the 2019 NDAA at deadline Monday for Weapons Complex Morning Briefing, but the text of Graham’s amendment was appended to a May 30 court filing by the state of South Carolina, which is suing to prevent the agency from shuttering the MFFF.

“None of the funds authorized to be appropriated or otherwise made available for the Department of Energy by this Act or any other Act for any fiscal year before fiscal year 2020 may be obligated or expended to terminate construction and project support activities at the MOX facility; or to convert the MOX facility to be used for any purpose other than its original mission,” the Graham amendment reads in part.

With Graham’s amendment tucked into the Senate’s version of the NDAA,, three of four major NNSA policy bills this year support continuing until at least fiscal 2020 the MFFF’s mission to convert 34 metric tons of plutonium into commercial nuclear reactor fuel. The House’s version of the 2019 National Defense Authorization Act, which cleared the floor with a strong bipartisan margin, authorizes continued construction of MFFF. The House Appropriations Committee also approved a 2019 NNSA budget that provides $335 million for MFFF construction and nothing for the NNSA’s proposed dilute-and-dispose alternative.

Only the Senate Appropriations Committee has gone along with the Donald Trump administration’s plan to cancel the project. On May 24, the committee approved a 2019 NNSA budget proposal that would give the agency the $220 million it sought in 2019 to halt construction.

In a May 23 letter to Robert Raines, NNSA associate administrator for acquisition and project management, the chief executive of MFFF prime contractor CB&I AREVA MOX Services said that if the NNSA halts construction, the first wave of project layoffs would result in the loss of some 600 employees by early August. Another 300 or so layoffs would follow, according to emails to Raines from MOX Services CEO Robert Wilson.