The U.S. Department of Energy plans to extend two major environmental cleanup contracts for up to a year at a contaminated nuclear site in Washington state.

The Tri-City Herald reported Tuesday that the extensions were granted at the Hanford Nuclear Reservation to allow work to continue uninterrupted while the Department of Energy completes the acquisition process that is underway.

The Energy Department said evaluations for the new contracts continue.

The Plutonium Uranium Extraction Plant was built in 1956 and is heavily contaminated after being used to help produce plutonium for the nation's nuclear weapons program.

RELATED: Cleanup estimate for Hanford nuclear site increases by $82 billion

Washington River Protection Solutions is expected to continue managing and retrieve 56 million gallons of radioactive waste in underground tanks.

CH2M Hill Plateau Remediation Co. is expected to continue cleanup at the site's center.

Also see | Washington state prevails over DOJ in Hanford workers' comp lawsuit