The Onkalo facility with the Olkiluoto plant in the background

Finland's Radiation and Nuclear Safety Authority has said it is on track to complete its assessment of Posiva Oy's operating licence application for the world's first used nuclear fuel repository and submit its statement to the Ministry of Economic Affairs and Employment "well before the end of the year".

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.

According to Project Manager Antti Tynkkynen, STUK is now in the final stages of assessing the operating licence.

"STUK has already received and processed a large part of the material and we have been able to start preparing the safety assessment," he said. "Once we receive the rest of the needed material and the clarifications we have requested, the assessment can be completed and the statement prepared quickly.

"A lot does also depend on Posiva's own schedules and whether they will make further changes to the final disposal systems," Tynkkynen added.

STUK said the effects of any changes must be assessed from the point of view of the safety justification concerning long-term safety. Posiva must provide detailed descriptions of even the smallest changes. That takes time, as does STUK's review.

STUK said that in the last third of 2024, it received several updated licence application materials from Posiva for review. Posiva has also made technical changes to the final disposal systems, which is why they have also updated the related materials for STUK to review.

"The process has also been delayed due to deficiencies and inconsistencies in the material Posiva has provided to STUK," it noted. "STUK has submitted requests for clarification to Posiva and is awaiting answers to several questions."

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 announced in late August the start of a trial run - expected to take several months - of the operation of the final disposal facility, albeit still without the used fuel.