Finland’s Radiation & Nuclear Safety Authority (STUK – Säteilyturvakeskus) in its monitoring report from the last third of 2023 indicates that Posiva Oy, which is responsible for the final disposal of used nuclear fuel, is progressing without major problems, but at a slightly slower pace than was previously anticipated. Posiva is constructing the world's first final used nuclear fuel disposal facility in Olkiluoto in Eurajoki. However, before it can start the operation of the facility it needs a permit from the Government. The permit decision requires a statement from STUK.

The Ministry of Labour & Business (TEM Työ- ja elinkeinoministeriö) had requested STUK's opinion by the end of 2023 but, as the processing of the licence application data is still ongoing at STUK has requested additional time from TEM for issuing the statement until the end of 2024.

STUK says in its third-year report that the material to be inspected for the safety assessment for the operating licence is very large. Furthermore, STUK has not always been able to make its assessments based on the materials first submitted by Posiva and has required updates. Therefore, the processing of the material has taken longer than expected.

Posiva, owned by Teollisuuden Voima Oyj’s Olkiluoto NPP and Fortum Power & Heat Oy’s Loviisa NPP, applied for a construction licence application to TEM in December 2013. Posiva investigated the rock at Olkiluoto and based its licence application on results from the Onkalo underground laboratory, which will be expanded to form the basis of the repository. The government granted a construction licence in November 2015 and work began in December 2016. The site for the repository was selected in 2000 and parliament approved the decision-in-principle for the project in 2001.

Posiva has been preparing for the disposal of used nuclear fuel for more than 40 years. Its encapsulation plant is located above ground, and the fuel repository of the underground disposal facility is located in the bedrock at a depth of approximately 400-430 metres. Once it receives the operating licence, Posiva can start the final disposal of used fuel generated by the two NPPs, which were hoping to use the facility between 2024 and 2070. The facility will operate for about 100 years.

By the end of 2023, STUK had not only prepared a safety assessment, but also continued to supervise Posiva and its work. The matters to be monitored include the installation of equipment in the encapsulation plant, test runs and test run plans, as well as the ongoing rock construction work in the underground final disposal locations. It is also monitoring and inspecting the security arrangements of Posiva's final disposal facility, the safety culture of the organisation and Posiva's readiness to start final disposal operations.


Image: Final disposal concept in Olkiluoto (courtesy of Posiva Oy)