Sellafield with extension options to 17 years. On 13 January 2015, the NDA announced that NMP would lose the management contract for Sellafield Ltd. as the "complexity and technical uncertainties presented significantly greater challenges than other NDA sites", and the site was therefore "less well suited" to the NDA's existing standard management model. The new structure, which came into effect on 1 April 2016, saw Sellafield Ltd. become a subsidiary of the NDA. Activities at the Sellafield site primarily support decommissioning of historic plants, and reprocessing fuel from UK and international nuclear reactors. Decommissioning projects include the Windscale Piles, Calder Hall,
Hartlepool Nuclear Power Station for a prototype fluidised bed combustion (FBC) coal station at Grimethorpe in Yorkshire. Because of this, the UK missed out on pioneering FBC technology, before it became internationally recognised as the best way of burning coal. Sited from Seaton Carew, and in the middle of the industrial complex of Teesside, the station was to be built closer to any major urban area than any nuclear power station site had been. To make this acceptable, the station's reactors were to be housed in prestressed concrete pressure vessels. The construction of the power station which was undertaken by Nuclear Design & Construction