Finnish fuel encapsulation plant enters installation phase

Posiva awarded Finnish construction company Skanska a contract for the used fuel encapsulation plant project preparation phase in November 2018. This was followed by a contract for the implementation phase of the project in June 2019. The value of that contract to Skanska was about EUR45 million (USD48 million). Construction of the facility began in September 2019.

Skanska Talonrakennus Oy has now handed over the completed building - some 72 metres in length and about 40 metres wide - to Posiva for the installation of the nuclear systems and commissioning of the process systems of the encapsulation plant.

"During the installation of nuclear systems, in particular, plenty of equipment and technology not in service anywhere else in the world will be introduced to the plant," Posiva noted.

It said the safety class SC3 crane to be used in the reception hall for the fuel transport casks has already passed the commissioning procedure. In addition, a remotely-operated manipulator has already been installed on the ceiling of the handling cell.

In addition to Skanska Talonrakennus Oy and its subcontractors, Ilmastointi Salminen Oy and Vesi-Vasa Oy have carried out work related to building services as Posiva's contractors. Sweco Oy is in charge of technical construction design, AFRY Finland Oy of electrical design and Elomatic Oy of the design of heating, ventilation, and air conditioning (HVAC) systems.

The encapsulation plant is part of Posiva's final disposal facility complex. Once the final disposal operation starts, used nuclear fuel will be transported from interim storage to the encapsulation plant where it will be packed into final disposal canisters made of copper and spheroidal graphite cast iron. From the encapsulation plant, the cannisters will be transferred into the underground tunnels of the repository, located at a depth of 400-450 metres, and further into deposition holes lined with a bentonite buffer. Operation of the repository is expected to begin in 2023.

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 - 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. Posiva is still required to obtain a separate operating licence for the facility.