Teollisuuden Voima Oyj’s Interim Report 1 January–30 September 2024

Electricity production at OL2 was suspended on 9 September 2024 due to an increase in humidity observed at the turbine plant’s generator. The plant unit reconnected to the grid on 6 October 2024 following the replacement of the failed rotor. Electricity production at OL2 will initially continue at a lower power level of 725 MW, while the plant unit’s full power output is 890 MW. Power has been limited in order to reduce the risk of rotor failure while the cause of the failure remains unclear. The power limitations are expected to last for several months, potentially until the next annual outage.

The scheduling of annual outages at the Olkiluoto power plant was modified in September 2024. The schedule estimates had been based on the duration of the planned work phases. The scheduling principles were now modified to also prepare for delays caused by unanticipated defect repairs based on earlier experience. The outage schedules for the Olkiluoto power plants have been announced until 2027.

The maximum production limitation of 1,570 MW set by the grid operator Fingrid Oyj (Fingrid) on OL3’s production has been increased to 1,590 MW. OL3’s power has also been limited in situations where adequate grid load limitation capacity has not been available from Fingrid. Furthermore, output at all three Olkiluoto plant units has been reduced in situations where electricity generation has been high in the Nordic countries. Production from all three plant units substantially supports Finland’s self-sufficiency in terms of electricity and helps in achieving the goals for carbon neutrality.

Since 1 September 2024, OL3 has been part of the down-regulation market of Fingrid’s frequency restoration reserve. This market is used for balancing the electrical grid in situations of temporary excess electricity generation. The Olkiluoto nuclear power plant units have previously not been included in the regulation market. Tenders for participating in the down-regulation market are made by TVO on the owners’ behalf.

An environmental impact assessment programme (EIA programme) concerning the possible service life extension and power uprating of the OL1 and OL2 plant units is under way and it is estimated to be completed during the latter part of the year.

In September 2024, TVO submitted to the Radiation and Nuclear Safety Authority (STUK) a special report concerning the brief exposure of four people to high radiation dose rates during a repair on hoist equipment at OL3 in June 2024. The exposure occurred during the lifting of a test fuel element. The exposure resulted in no personal injuries.

The test operation of final disposal for spent nuclear fuel (joint functional test) started at Olkiluoto on 30 August 2024. The joint functional test involves testing the final disposal without spent nuclear fuel. During the test operation stage, equipment and systems of the disposal facility will be operated together for the first time, in accordance with the planned processes. The test operation ensures safe final disposal before the actual operations are started.

The processing of Posiva’s operating licence application at STUK is progressing. STUK’s safety assessment and statement concerning the operating licence application of the disposal facility for spent nuclear fuel is expected to be complete in the coming months.

Full Interim Report can be found here.