Originally known as the Nuclear Industry Radioactive Waste Executive, it became the limited company United Kingdom Nirex Limited in 1985. The ownership of Nirex was transferred from the nuclear industry to the UK Government departments DEFRA and DTI in April 2005, and then to the UK's Nuclear Decommissioning Authority (NDA) in November 2006. Nirex's staff and functions were integrated into the NDA in April 2007, at which point Nirex ceased trading as a separate entity. Nirex's role continues through the activities of the Radioactive Waste Management Directorate of the NDA.
Nirex had gained widespread notoriety during the 1980s as the focus for widespread public opposition to the burying of nuclear waste in the UK. Nirex was based at Harwell, Oxfordshire and had several roles:
Nirex was also involved in keeping the UK abreast of international expertise in research and development into the disposal of radioactive waste.
During the mid 1980s proposals for nuclear waste repositories at Billingham, Elstow, Bradwell, Fulbeck, and South Killingholme were abandoned due to local opposition. In October 1992 Nirex announced plans to build a “Rock Characterisation Facility” or RCF at Sellafield. Nirex critics including Cumbria County Council, Friends of the Earth and Greenpeace argued that the RCF was an integral part of Nirex's repository plans and in effect a 'trojan horse' for an intended nuclear waste repository. It was also successfully argued that the RCF proposal was scientifically flawed; and that Nirex's scientific knowledge was insufficient to prove that disposal was safe for any site. In 1997, following a five month local planning inquiry, the Secretary of State for the Environment rejected Nirex's case.
The Inquiry Inspector said “chemical containment is new and untried, with more experimentation and modelling development indubitably required. This work would to my mind be particularly difficult and important because of the problems of meaningfully testing some of the components of the concept. Implicitly Nirex feels unable to credit the notion that this barrier would fail; but the lack of any calculation based on an adverse, as distinct from a conservative, interpretation of this chemical containment seems to me to be an unfortunate omission from the emerging safety case, particularly having regard to FOE's impressive critique of the concept.”