ATK Energy EU Ltd (a United Kingdom subsidiary of SNCL), together with its legacy subsidiaries held the contracts and licenses to operate, defuel, and decommission 22 Magnox nuclear power reactors at 10 geographically dispersed sites (904 acres comprising 1,000 buildings and 10M ft2 of floor space, including reactor buildings, turbine halls, spent fuel storage ponds and handling facilities, waste management facilities, and ancillary buildings/infrastructure). This work was performed on behalf of the Nuclear Decommissioning Authority (NDA), a UK Government entity similar to DOE Environmental Management (EM) in mission and purpose.