Lisa Gordon-Hagerty, NNSA, Aiken Tech

National Nuclear Security Administration chief Lisa Gordon-Hagerty pictured here speaking at Aiken Technical College this year.

The federal government has quietly moved a total 1 metric ton of weapons-grade plutonium out of South Carolina, chipping away at a stockpile of potentially lethal nuclear material still at the Savannah River Site.

The cross-country move, done to comply with a late 2017 federal court order, was disclosed Wednesday evening by S.C. Attorney General Alan Wilson, who had sued the U.S. Department of Energy over the stockpile. The DOE had faced a January 2020 deadline to remove the material.

"Today's news that one ton of weapons-grade plutonium has been removed from the state is a victory for South Carolinians and the rule of law," Wilson said in a prepared statement. "The Department of Energy disregarded many of its obligations to the state, and this outcome confirms the state will not sit idly by while the department does so."

Still, roughly 11 metric tons of the nuclear material remain at the Savannah River Site, a 310-square-mile nuclear complex 20 miles south of Aiken and about 130 miles northwest of Charleston. The material is stored at an aging reactor-turned-nuclear-storehouse that has previously been described as in poor condition.

The move comes at a time when Wilson and the state's legal team are trying to get the federal government to pay $200 million in fines levied against the Energy Department for failing to remove the plutonium in a timely manner. The Energy Department has repeatedly drawn the ire of U.S. Sen. Lindsey Graham, R-S.C., and S.C. Gov. Henry McMaster.

Federal law had mandated – beginning Jan. 1, 2016 – that DOE pay South Carolina $100 million for every year it failed to process plutonium at the never-completed Mixed Oxide Fuel Fabrication Facility at SRS or get 1 metric ton of the material out of the state.

DOE had been ordered by a federal court to remove at least 1 metric ton of the material from the site by the start of 2020. The Energy Department's weapons and nonproliferation arm, the National Nuclear Security Administration, has now completed the effort months ahead of the deadline.

To comply with the court order, a half-metric ton was shipped to Nevada prior to November 2018, according to federal court documents. That clandestine campaign incensed that state's governor and its congressional delegation, who complained the shipment was only disclosed after a lawsuit was filed to prevent such a move from happening.

It is not immediately clear where the remaining plutonium – about a half-metric ton – went. Wilson's announcement does not include information about that, and the Energy Department and its semiautonomous NNSA rarely discuss timelines and routes taken, citing security concerns.

But a July 2018 environmental analysis listed Texas, Nevada and New Mexico as potential destinations.

The 1 metric ton in question is intended for use in weapons, according to the environmental study. It would be used to create nuclear weapon cores – triggers – known as plutonium pits.

"This material will ultimately be used for vital national security missions and is not waste," then-NNSA Chief of Staff William "Ike" White wrote in a letter to Nevada leaders last year.

The plutonium pit work would be done at Los Alamos National Laboratory, which is located in northern New Mexico.

The Nevada National Security Site, northwest of Las Vegas, and the Pantex Plant, northeast of Amarillo, Texas, would be staging sites, according to the study. U.S. Secretary of Energy Rick Perry has promised to remove the contentious half-metric ton of plutonium from Nevada by the end of 2026.

In the lead up to Wednesday's declaration, Energy Department and NNSA officials had repeatedly expressed confidence in their shared ability to meet the 2020 South Carolina removal deadline.

Court-required progress updates furthered that narrative.

"The department has devoted significant resources and attention to complying with the court's injunctive order while at the same time ensuring that the removal of defense plutonium occurs as safely as possible in compliance with all applicable laws," one update reads.

In a June interview with the Aiken Standard, NNSA chief Lisa Gordon-Hagerty said the 1 metric ton would "absolutely" be out of the Palmetto State by the end of the year, even making a verbal guarantee.

Gordon-Hagerty, who is also the Energy Department's under secretary for nuclear security, in the same interview said the removal effort is "certainly" resource-intensive, alluding to taxpayer impact.

Colin Demarest is the government and Savannah River Site reporter with the Aiken Standard. Follow him on Twitter: @demarest_colin