Finnish approach to safeguard in the context of geological disposal of spent nuclear fuel

Olkiluoto, situated at the west coast of Finland, was approved as a site for final disposal of Finnish spent nuclear fuel. The decision-in-principle (DIP) was made by the government and ratified by Parliament in May 2001 by a clear majority of votes (159 votes were in favour, only three were against, and there were 37 abstentions). Hosting municipality, Eurajoki, had also supported the DIP application earlier with clear majority. From now on Posiva, the company who is responsible for the final disposal of spent nuclear fuel, will perform detailed investigations in the Olkiluoto area. Above all, this includes construction of underground rock characterisation facility, ONKALO, which goes 400-600 m deep under the Earth's surface. Excavations of ONKALO will begin in 2004. It is expected, that the ONKALO will become a part of final underground repository. The construction licence for final disposal plant, comprising of an encapsulation facility and an underground repository, will be applied around 2012 and construction process of is planned to start 2013-2014. According to current plans operation of the plant will start 2020. Safeguarding final disposal process is a challenge. Design information verification of underground facility is difficult after construction of the tunnels. Some geophysical methods exist to perform design information verification after construction, but they may create ambiguous results. Re-verification of nuclear fuel, which is a cornerstone of present safeguards approaches, will not be possible after disposal. The roles and responsibilities of the parties involved (operator, STUK., EURATOM, IAEA) must be determined with care. (author)