GEOLOGIC DISPOSAL OF SPENT NUCLEAR FUEL: FINNISH PERSPECTIVE

Olkiluoto Island, which is located in SW Finland, has been designated as the final repository for the high-level nuclear waste generated by the nuclear power plants operated by the power companies Teollisuuden Voima Oyj (TVO) and Fortum Power & Heat Oy (Fortum), and the repository is expected to become operational approximately at 2020. Posiva Oy is an expert organisation responsible for the management and implementation of the nuclear waste repository at Olkiluoto and is owned by TVO and Fortum. By the end of 2012, Posiva Oy submitted the application for construction licence for the final disposal facility and as such reached a significant milestone in the project. In the future, the work carried out at Olkiluoto will increasingly focus on the preparation of the implementation of the actual final disposal facility. A total of 9,000 tonnes of high-level nuclear waste will be disposed of from the four existing nuclear power plant units, the one currently under construction at Olkiluoto (Olkiluoto 3) and the planned sixth unit (Olkiluoto 4).

The Palaeoproterozoic bedrock at Olkiluoto (1.9–1.8 Ga) comprises mainly of supracrustal highgrade metamorphic rocks with evidence of polyphase deformation. The general suitability of the Olkiluoto bedrock for the final disposal of nuclear waste has been confirmed with studies carried out in the underground characterization facility, located in the central part of Olkiluoto and called ONKALO. The data from the investigations carried out in the underground facility and surface have been used to develop procedures for locating suitable rock volumes for the final disposal facilities, that is, tunnels and disposal holes. In the next few years, Posiva will carry out a series of tests in the underground research facility to ensure adequate competence and preparedness prior the onset of the actual final disposal.