Further delay in Finnish repository licence review

Radioactive waste management company Posiva submitted its application, together with related information, to the Ministry of Economic Affairs and Employment on 30 December 2021 for an operating licence for the used fuel encapsulation plant and final disposal facility currently under construction at Olkiluoto. The repository is expected to begin operations in the mid-2020s. Posiva is applying for an operating licence for a period from March 2024 to the end of 2070.

The government will make the final decision on Posiva's application, but a positive opinion by the Radiation and Nuclear Safety Authority (STUK) is required beforehand. The regulator began its review in May 2022 after concluding Posiva had provided sufficient material. The ministry had requested STUK's opinion on the application by the end of 2023. However, in January last year, STUK requested the deadline for its opinion be extended until the end of 2024. In December, the ministry extended the deadline for the regulator's opinion to 31 December 2025.

The ministry has now extended the deadline until the end of June 2026, "if it is possible to do so by then". According to STUK, the new timetable is possible, but tight, for both the authority and the licence applicant.

Although STUK's assessment of the application is in the final stages, the statement and safety assessment cannot be completed until it has assessed and approved all of Posiva's operating licence application materials.

"We have already received and approved most of Posiva's operating permit application materials," said STUK Project Manager Antti Tynkkynen. She said STUK has still made requests for clarification on the latest materials updated by Posiva, and expects to receive Posiva's responses in early 2026.

"Overall, the processing of the operating licence application is close to completion, but delays have been caused by deficiencies in the documentation, updates due to plant modifications made by Posiva, and the scope of the updates," STUK said in its latest quarterly report on its assessment. "In addition, STUK has identified uncertainties in the safety case review, the effects of which on long-term safety still need to be analysed."

At the repository, used fuel will be placed in the bedrock, at a depth of about 430 metres. The disposal system consists of a tightly sealed iron-copper canister, a bentonite buffer enclosing the canister, a tunnel backfilling material made of swellable clay, the seal structures of the tunnels and premises, and the enclosing rock.

The government granted Posiva a construction licence for the project in November 2015 and construction work on the repository started in December 2016. Once it receives the operating licence, Posiva can start the final disposal of the used fuel generated from the operation of TVO's Olkiluoto and Fortum's Loviisa nuclear power plants. The operation will last for about 100 years before the repository is closed.

"Posiva's project is the first in the world, so it understandably takes time to justify things and requires great care and expertise," STUK said. "In particular, the demonstration of the performance of the clay material, which acts as one of the barriers to the spread of radioactive substances, is still under way. Posiva replaced the clay material in the original plans with another, and the effects of the new material on the long-term safety of the final disposal still need to be assessed."