The Three Mile Island nuclear power plant unit that partially melted down in 1979 and shut down since was acquired Oct. 15 by Utah-based cleanup firm EnergySolutions in what it says will be its most technically challenging decommissioning project to date.

The contract at the Middletown, Pa., site needs a sign-off by the U.S. Nuclear Regulatory Commission and state regulators and is not set to be final until next year.

The purchase of Unit 2 from First­Energy Corp. includes its license and estimated $871-million waste cleanup trust fund. The unit has been in monitored storage for 26 years. About 99% of its nuclear fuel was removed and shipped for storage at the Idaho National Laboratory.

EnergySolutions and Jingoli, a New Jersey nuclear power construction firm, have a joint venture to decommission the unit. The firms now are involved in project planning prior to the sale close, with actual remediation not set to start for several years. 

Exelon, the utility company owner of Thhree Mile Island's Unit 1 since 1999, shut down its operation on Sept. 20 for economic reasons. State legislators in May failed to pass a $500-million bailout to keep the plant open. Its decommissioning plan is unclear.

For Unit 2, decommissioning will include disassembly and segmentation of remaining reactor vessel internals; segmentation of the reactor vessel and vessel head; and removal of steam generators, freestanding concrete and other remaining internal structures after earlier meltdown cleanup.

Unit 2’s decommissioning schedule under NRC’s SAFSTOR method calls for work to begin in 2041 finish by 2053.

EnergySolutions is expected to propose an accelerated process. Schedule changes will be made public later, a firm spokesman told ENR, also citing “best practices and lessons learned from other decommissioning projects.”

EnergySolutions has used NRC’s quicker method of decommissioning at the two-unit, 2,080-MW Zion Nuclear station in Illinois, where cleanup was accelerated by 12 years and will be complete next spring.

The firm also will finish takedown of the 50-MW La Crosse station in Wisconsin next year. It took over the plant in 2016.

Energy­Solutions in April signed a contract to decommission the 484-MW Fort Calhoun Nuclear power station in Nebraska.