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,
Koeberg Nuclear Power Station too expensive to be viable. Nuclear power was considered because it was more economical than transporting coal to the existing fossil-fuel power stations, and construction of new fossil-fuel power-stations, which would have required 300 m tall chimneys to comply with clean-air legislation. Athlone Power Station in the city was too small to provide Cape Town's needs, and the Paarden Island power station (itself too small) has been demolished. Koeberg was one of the first nuclear power stations designed to be specifically resistant to earthquakes. The reactors at the Koeberg nuclear power station are built upon an aseismic raft designed –