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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 Onkalo final disposal facility. The company is applying for an operating licence for a period from March 2024 to the end of 2070. The encapsulation plant and final disposal facility are intended for the used nuclear fuel generated by TVO's Olkiluoto and Fortum's Loviisa nuclear power plants.
A prerequisite for the government making the final decision on Posiva's application was a positive opinion by the Radiation and Nuclear Safety Authority (STUK). 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 before extending it, in stages, until the end of June 2026. STUK published its safety assessment of Posiva's encapsulation and final disposal facility for used nuclear fuel on 4 August this year, saying the facility meets the safety requirements set for it in the Nuclear Energy Act and Decree, and, "therefore, there is no obstacle to granting the facility an operating licence with regard to radiation and nuclear safety".
The government has now granted Posiva the operating licence taking into account STUK's opinion.
The licence granted to Posiva allows the company to possess, process, store and dispose of a maximum of 6,500 uranium tonnes (tU) of used nuclear fuel generated by the Olkiluoto and Loviisa plants. Under the licence conditions, Posiva may possess, produce, process, store and dispose of low-level and intermediate-level radioactive waste generated by the encapsulation plant and final disposal facility and by the operation and decommissioning of nuclear facilities owned by its shareholders - TVO and Fortum - provided that the total volume of the waste does not exceed 3,000 cubic metres, of which no more than 1,500 cubic metres may be designated for final disposal.
The licence also permits the final disposal of certain other radioactive waste and nuclear materials generated in Finland to a limited extent. This includes certain radioactive waste generated in healthcare and research institutions.
The amount of used nuclear fuel to be disposed of corresponds to approximately 3,300 disposal canisters. Once operations are fully established, the plan is to dispose of a maximum of 60 canisters annually at the plant. The final disposal operations are estimated to continue until the 2120s, after which the repository will be backfilled and closed. After the closure of the facility, responsibility for the used nuclear fuel will be transferred to the State in accordance with the Nuclear Energy Act.
Posiva must ensure that the data sets essential for the final disposal operations are specified and stored to make them available to the State after the closure of the final disposal facility.
Before the facility is commissioned, STUK will conduct the inspection referred to in section 20 of the Nuclear Energy Act to ensure that all conditions for safe operation have been met. Despite the decision on the operating licence issued by the government, Posiva may not start operating the facility before STUK has conducted the inspection.
Posiva is required to submit a periodic safety assessment and an updated long-term safety justification to STUK within ten years of the granting of the licence. Periodic safety assessments will also be carried out during the operation of the facility in accordance with nuclear energy legislation.
"Finland's strong safety culture underpins the production of clean energy," said Minister of Climate and the Environment Sari Multala. "It is our responsibility across generations to ensure the safe and responsible use of nuclear power, from construction through to the final disposal of spent fuel. As a result of more than 40 years of systematic efforts, Finland will launch the first final disposal facility for spent nuclear fuel in the world."
"The decision marks the beginning of a new stage in a process that has continued for more than 40 years," Posiva said. "Posiva will now transition towards production operation which will go on for over a hundred years." However, it added: "The operating licence does not imply an immediate start to production operation. Before final disposal begins, Posiva will finalise the commissioning stage, carrying out the necessary tests and inspections which STUK also needs to verify and approve. No detailed schedule is given at this point for the start-up."
"This is a great and historic day for both Posiva and Finland. In addition to comprehensive expertise, the stability of the society and the predictability of the operational environment were prerequisites for the operating licence" said Posiva President and CEO Ilkka Poikolainen. "This solution has not been built because it was easy. It was built despite not being easy. Because it is the responsible thing to do. And because it is the right thing. Like we have said from the very start: only safe final disposal is possible. That is why we will take the time to complete also the final stages with care."
"A total solution like this is not built by just one organisation, and not in just a few years' time. It has its background in the forward-looking decisions of the society, independent regulatory oversight, strong commitment from our owners, and the efforts of a wide-reaching group of experts. The thanks must go to everybody involved in this work," Poikolainen said.
A deep geological repository comprises a network of highly-engineered underground vaults and tunnels built to permanently dispose of higher activity radioactive waste so that no harmful levels of radiation ever reach the surface environment. Countries such as Sweden, France, the UK and the USA are also pursuing this option.
At Onkalo, used nuclear fuel will be placed in the bedrock, at a depth of about 450 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 first final disposal tunnel that is now being worked on is about 330 metres long and will house a total of about 30 drilled deposition holes.
In late August this year, ahead of being granted an operating licence, Posiva announced that workers had begun drilling the first deposition hole for use at the Onkalo underground used nuclear fuel repository. The drilling of the first deposition hole using the Deposition Hole Boring Machine (DHBM) was started in the 1.9-billion-year-old Olkiluoto bedrock at a depth of more than 400 metres. The deposition hole now under construction is being drilled vertically into the floor of a previously excavated final disposal tunnel. The finished hole will have a depth of 8.4 metres and a diameter of 1.75 metres.
The Onkalo repository
The site for Posiva's repository at Eurajoki, near the Olkiluoto nuclear power plant, was selected in 2000. The Finnish parliament approved the decision-in-principle on the repository project the following year. Posiva - jointly owned by Finnish nuclear utilities Fortum and Teollisuuden Voima Oyj (TVO) - submitted its construction licence application to the Ministry of Employment and the Economy in December 2013. Posiva studied the rock at Olkiluoto and prepared its licence application using results from the Onkalo underground laboratory, which would be expanded to form the basis of the repository. The government granted a construction licence for the project in November 2015 and construction work on the repository started a year later.
In July 2022, Posiva announced that the excavation of the first five actual disposal tunnels had been completed. The total length of the tunnels, whose excavation began in May 2021, is about 1700 metres. It is estimated that 100 deposition tunnels will be excavated during the 100-year operational period of the final disposal facility, and will have a total length of about 35 kilometres. The maximum length of each tunnel will be 350 metres. The tunnels will be about 4.5 metres high and about 3.5 metres wide.
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