Sellafield was the site of the world's first nuclear power plant and decades of weapons-making operations.

The U.S.-led team managing multi-billion-dollar decommissioning of the U.K.-based Sellafield site, Europe’s most complex civil nuclear-energy site, will have its contract ended less than one year into its second five-year term.

The U.K.'s Nuclear Decommissioning Authority will retake control of the site license company, Sellafield Ltd., which is now owned by the private consortium called Nuclear Management Partners Ltd. (NMP).

The authority determined that cleanup and decommissioning of the 4-kilometer complex posed too many technical difficulties for NMP and cited problems in its progress.

NMP is led by AECOM, which took over after completing acquisition last fall of URS Corp., which had been consortium leader. The team also includes members AREVA N.C., Paris, and Amec Foster Wheeler plc, London.

The consortium acquired Sellafield Ltd. under a five year extendable contract in 2008. NDA renewed the contract for five more years last April.

The team “brought stability to the site … and delivered important progress on key projects,” said U.K. Energy Minister Ed Davey, but he said that NDA needed to implement a different approach.

“We are surprised and naturally disappointed, especially in light of the considerable progress made at Sellafield since NMP was awarded the contract in 2008,” says Iain Irving, NMP General Manager.

Housing most of the U.K.’s civil nuclear waste from nuclear power and weapons making dating to the 1940s, Sellafield accounts for 60% of NDA's $4.6-billion annual spending.

Rather than outsourcing full control of the site, NDA will emulate strategies used on London’s current Crossrail project and the 2012 Olympic and Paralympic Games by employing what it terms a project delivery parent.

The decision follows a review of various commercial approaches “where the combination of public and private sector comes together to deliver complex programs and taxpayer value,” says NDA’s chief executive officer John Clarke.

Last February, the U.K parliament’s Public Accounts Committee slammed NMP’s progress at Sellafield. “NMP has failed to provide the clear leadership, strong management and improved capabilities,” claimed committee chair Margaret Hodge, citing big delays and huge cost overruns.

Sellafield was the site of world’s first nuclear power plant and later a fuel recycling and waste storage facility.

About 240 of the its 1,400 buildings are nuclear-related.