The US Court of Appeals for the Fourth Circuit on Tuesday allowed the US Department of Energy (DOE) to halt construction on a mixed oxide fuel (MOX) fabrication facility project in South Carolina.

The appeals court granted a motion to stay an injunction granted by the US District Court of South Carolina that had prevented the DOE and National Nuclear Security Administration (NNSA) from ending construction on the plant.

The MOX facility blends weapons-grade plutonium into fuel for use in commercial nuclear power plants. Construction on the facility began in 2007. The DOE intended to stop construction on the project and instead dispose of plutonium through a dilute and dispose method. The state of South Carolina petitioned for the injunction to prevent the DOE and NNSA from ending construction on the project.

The district judge granted the injunction against the DOE and NNSA because there has been no official commitment to remove the plutonium from South Carolina and no certification has been provided that the alternative plan is less expensive. Although some plutonium is being removed from South Carolina to be sent to the Waste Isolation Pilot Plant (WIPP) in New Mexico, none of the plutonium being sent to WIPP was intended to be disposed of in the MOX facility. The district court ruled that a certification of cost that was provided by the DOE would likely not meet accuracy requirements. The district court also found that the DOE needed to complete an environmental impact for the plutonium which is to remain in South Carolina.

The court of appeals’ order will allow the DOE and NNSA to grant a stop work order on the construction of the MOX facility. The DOE originally planned on issuing a stop work order on June 11. The court of appeals gave no explanation on why the motion of stay was granted.