Finnish power company Teollisuuden Voima Oyj (TVO) on 8 December applied to Finland's Radiation and Nuclear Safety Authority (STUK) for permission to bring the EPR at unit 3 of the Olkiluoto NPP (OL3) to first criticality and conduct low-power tests.
TVO said start up of the unit may be brought forward from the previously announced date of January 2022. "TVO, together with the plant supplier Areva-Siemens consortium, has established that the OL3 EPR project has progressed faster than previously communicated," the company said. "On this basis, TVO has submitted a permission application for making the reactor critical and conducting low-power tests."
The unit will not be connected to the grid during the low-power tests. However, TVO said once permission has been granted, it “will communicate its potential effects on the schedule for starting electricity production”.
The Areva-Siemens consortium is constructing the OL3 plant under a fixed-price turnkey contract. They have joint liability for the contractual obligations until the end of the guarantee period of the unit. Construction of Olkiluoto 3 began in 2005. Completion of the reactor was originally scheduled for 2009, but the project has faced a series of delays and setbacks.
In May, TVO reached a consensus with the plant supplier on project completion, noting then that OL3 was scheduled to be connected to the grid in October 2021 and to begin regular electricity production in February 2022. In August, TVO announced that, due to extended turbine overhaul and inspection works, there would be a further three-month delay to start-up, with first criticality now expected in January 2022, initial electricity production in February 2022 and regular electricity production in June 2022.
Fuel has already been loaded into the core of OL3. The reactor is now in a commissioning phase during which time TVO has conducted a new series of hot functional tests to verify the plant's systems work correctly. Initial hot functional tests - carried out without nuclear fuel in the reactor - were completed in 2018.