NDA The Nuclear Decommissioning Authority (NDA) is a non-departmental public body of the Department for Business, Energy and Industrial Strategy, formed by the Energy Act 2004. It evolved from the Coal and Nuclear Liabilities Unit of the Department of Trade and Industry. It came into existence during late 2004, and took on its main functions on 1 April 2005. Its purpose is to deliver the decommissioning and clean-up of the UK’s civil nuclear legacy in a safe and cost-effective manner, and where possible to accelerate programmes of work that reduce hazard. The NDA does not directly manage the UK's nuclear sites. It oversees the work through contracts with specially designed companies known as Site Licence Companies. The NDA determines the overall strategy and priorities for managing decommissioning.