The decommissioning of nuclear facilities

Decommissioning measures are aimed at cleaning the nuclear power plant structures and systems of radioactive materials, so that the licensee is released from all obligations relating to the licence. In Finland, radioactive waste generated during the decommissioning is mainly disposed of in facilities built in final disposal repositories on the power plant sites.

Necessary technical release barriers are built around the waste and the facilities are closed. In Finland, decommissioning is carried out in such a way that the site can be used as an industrial area after the measures.

Worldwide, operations have ceased in over one hundred nuclear power plant units, and in addition to this, several hundred research reactors and other nuclear facilities have reached the end of their life span. Dismantling of nuclear installations is largely low and intermediate-level waste management: cutting, packaging and disposal of steel and concrete structures. From a radiation protection view, the work is demanding, as some parts of the power plant emit a high level of radiation. While dismantling structures, radioactive dust must be prevented from dispersing and getting into the air.

While the Loviisa and Olkiluoto nuclear power plants will operate for a further 10–35 years, detailed decommissioning plans for the facilities have been drawn up. The plans are updated every six years. The plans are assessed by the Ministry of Economic Affairs and Employment and STUK. Planned new nuclear facilities are also required to take into account the decommissioning stage already during the nuclear facility planning stage. According to the plans, decommissioning will start at the Loviisa units according to a rapid schedule a couple of years after the closure of the plant, i.e. in early 2030s. Decommissioning of the Olkiluoto 1 and 2 units is carried out in a delayed manner, decades after the closure of the plant, approximately in the 2070s.

The first decommissioning of major nuclear power plants has already been completed in the world. The cost and execution are affected by the type of reactor. The decommissioning costs of light-water reactors are estimated to be about 10 per cent of the construction cost of a similar facility.