Finland's Radiation and Nuclear Safety Authority (Stuk) has announced that more time is needed to review the operating permit application from Posiva, the firm responsible for the final disposal of spent nuclear fuel from nuclear facilities operated by TVO and Fortum.
Posiva is building the Onkalo storage cave more than 400m below the surface of Olkiluoto Island on the southwest coast. The firm says it will be the world's first safe final disposal site for nuclear waste.
According to the original timetable, final disposal of spent fuel rods from the Olkiluoto and Loviisa nuclear power plants was to have begun there this year.
Stuk said it spent the second quarter of the year processing the permit application, adding that the process is still ongoing, according to a press release issued on Tuesday.
The watchdog said it was not sure how long it will take to complete the assessment, noting that it involves a large amount of data. It has requested Posiva to update some of the information.
Ultimately, the government will make the final decision about issuing the permit, but it can only grant permission if Stuk's assessment is positive, according to the authority.
It said that the Ministry of Economic Affairs and Employment has asked Stuk to submit its opinion on the matter by the end of this year.
However, Stuk said it is preparing to seek a postponement of that deadline.
Stuk granted Posiva permission to begin excavation of the nuclear fuel repository in 2021.
Founded by TVO and Fortum, Posiva is in charge of disposing spent nuclear fuel and has been working on efforts to construct the repository for more than 16 years.