COLUMBIA — The Department of Energy is reviewing bids from companies who want to operate part of the Savannah River Site, the sprawling former nuclear weapons complex near Aiken.

The site's current contract is worth more than $1 billion and the work is being split up between operating the decade-old site and environmental cleanup, and managing nuclear waste left over from Cold War weapons production.

The bidding closed in June to handle environmental cleanup and operate the Savannah River National Laboratory in a contract worth about $722 million.

"The bids are in and we're evaluating them," Energy Department spokesman Jim Giusti said Tuesday. No date is set for announcing the winner. The existing contract ends in June 2008.

Two companies are bidding for work, which employs about 6,200 people. Washington Savannah River Co. has been the primary contractor at the site since 1989, when it bought Westinghouse Government Services. A partnership led by Fluor Corp., Savannah River Nuclear Solutions, also is bidding for the contract.

The Energy Department now is developing bid documents for Savannah River's other primary operation: managing liquid nuclear waste left over from the Cold War. About 2,500 people work at the site monitoring and handling some of the nation's most radioactive materials, including what dating back to Savannah River's role in producing nuclear weapons.

The Washington group also plans to bid for that work; the Flour-led group will not.