Contractor teams now managing two of the U.S. Energy Dept.’s largest nuclear waste cleanup projects at its giant Hanford former weapons site in Washington state gained new contract extensions.

The agency decided this month to delay planned multiyear awards because it is still weighing bidding team proposals and lacks sufficient time for contract transition.

The estimated 10-year contracts, worth at least $23 billion in total, had been set to take effect on Oct.1.

The latest one-year extensions were announced in an Aug. 13 memo sent to DOE Hanford site employees, according to the Tri-Cities Herald newspaper in Richland, Wash.

One of the affected contracts is held by Washington River Protection Solutions, led by AECOM and Atkins.

It involves work to maintain and finally close 144 aging underground waste tanks in the next decade. The tanks, built since World War II, once stored up to 56 million gallons of chemical and radioactive waste.

The contractor is one of three teams said to be vying for the estimated $13-billion follow-on award. Others are Fluor Corp., teamed with BWX Technologies; and Jacobs Engineering with Honeywell.

The other contract, now held by Jacobs’ CH2M unit to manage cleanup in the 560-sq-mile Hanford site’s central region, is valued at about $10 billion.

It includes management of a highly radioactive and decaying former plutonium handling plant that is seen as a growing environmental risk to the site, but whose demolition plan could still be more than a decade away, as well as removal of contaminated sludge near the Columbia River and groundwater treatment.

The tank farm and central Hanford contracts are set to be indefinite-delivery/indefinite-quantity awards, with work done through individual task orders. Contract bidders have not been identified.

Jacobs moved to boost its sector expertise, with an Aug. 20 announcement of a deal to buy the nuclear business of Wood Group PLC for about $300 million that is set to close next year.

While the unit has worked primarily in the U.K., it includes a 2,000-person staff and provides “technical and consulting services across the nuclear life cycle, including new build, operational support and decommissioning,” said Credit Suisse stock analyst Jamie Cook.