Posiva Oy is a nuclear waste management company, owned jointly by Teollisuuden Voima Oy (60%) and Fortum Power and Heat Ltd. (40%). Posiva Oy is responsible for research into the final disposal of spent nuclear fuel of the owners and for the construction, operation and eventual decommissioning and dismantling of the final disposal facility.

In December 2003 a programme for monitoring at Olkiluoto during construction and operation of ONKALO (the underground rock characterization facility) was presented. A summary of the observations and measurements is reported annually for five disciplines: Rock Mechanics, Hydrogeochemistry, Hydrology and hydrogeology, Environment and Foreign Materials.

Key role in consortium: Participation in work packages 1, 2, 5 and 6.

Key participant: Jere Lahdenperä