AIKEN, South Carolina - The US Department of Energy has sealed off access to two reactors at a former nuclear weapons plant near the South Carolina-Georgia border.

Energy officials say the P and R reactors at the Savannah River Site were sealed off Wednesday with about 260,000 cubic yards (200,000 cubic meters) of concrete grout.

The reactors have been shut down for more than 40 years. The cleanup was funded as a stimulus project.

The complex near Aiken, South Carolina, received $1.6 billion in federal stimulus money to create or save more than 3,000 jobs at the site, which once produced plutonium and tritium for nuclear bombs.

Work is now focused primarily on research and cleaning up areas contaminated during weapons production.