EPR unit expected to become commercial in summer 2022 An aerial view of the Olkiluoto nuclear power station in western Finland, showing the newest Olkiluoto-3 EPR plant and the older Olkiluoto-1 and -2 in the background. Courtesy TVO. Finnish utility Teollisuuden Voima Oyj (TVO) has asked national nuclear regulator Stuk for permission to proceed towards first criticality for the Olkiluoto-3 EPR plant in western Finland, the company said in a statement.

According to the statement, TVO also seeks regulatory authorisation to carry out low power tests at the 1,600-MW Generation III EPR unit, supplied by an Areva-Siemens consortium.

First criticality at a nuclear plant means achieving a controlled, self-sustaining nuclear fission chain reaction in the reactor core for the first time.

Areva said hot functional testing at Olkiluoto-3 progressed faster than earlier announced. Fuel was loaded for the first time in the reactor core in late March 2021 followed by hot testing in July.

According to the latest project schedule from August 2021, first criticality was scheduled for January 2022 with first electricity production in February 2022 and regular electricity production in June 2022.

TVO said in June that it had signed agreements with the Olkiluoto-3 EPR plant supplier consortium companies regarding the terms of project completion.

TVO and the plant supplier consortium companies had been negotiating the terms of the project completion since summer 2020.