In 1991 a consensus was reached the International Atomic Energy Agency, OECD Nuclear Energy Agency and nuclear industry and research representatives of the EEC/EU that underground storage of high-level waste (HLW) is a safe means of long-term waste disposal. The "concentration and containment" strategy, the primary one used by the nuclear industry in western Europe, involves reprocessing spent fuel and separating off a carefully segregated stream of HLW containing over 99% of the total radioactivity. Over the coming years it is intended that these HLW arisings will progressively be incorporated into large, highly stable borosilicate glass blocks, which is a form particularly suitable for long-term storage and final disposal. Work is also continuing on several complementary approaches to waste-management, such as the characterization of radioactive mixed waste products, spent fuel pre-processing, conditioning (in concrete or bitumen) and concentration, and the safety of subterranean radioactive waste (radwaste) repositories.
In Sweden, the Ã„spÃ¶ hard rock project is proceeding with the excavation of a tunnel from the mainland and two spiral boreholes beneath the island to the site of the laboratory 500 metres below ground level. Canada, Finland, France, Japan, the USA and Nirex, the British nuclear waste consortium, are co-sponsors of the project. Nirex also has a project half a mile into the bed-rock below Borrowdale (close to Sellafield). It expects to spend up to five years researching the nature of the rock where it is eventually hoped to develop a major radwaste repository, starting use by 2006-2007. The Hades underground laboratory at Mol, Belgium is also investigating the use of the deep clay substratum for a high-level waste repository.