STUK’s supervision ensured the safety of nuclear power plants

In 2023, the Radiation and Nuclear Safety Authority (STUK) supervised the safety of the nuclear power plants in operation and ensured that current decrees and regulations were complied with and that there were no significant incidents that jeopardized safety. Last year, STUK carried out a total of 36 inspections in accordance with the operational inspection programme at the nuclear power plants in Loviisa and Olkiluoto. Some of the inspections were related to the annual maintenance of the plants.

Nuclear safety supervision is based on the obligations and responsibilities set out in the Nuclear Energy Act (990/1987). The licensee must ensure safety, and STUK confirms through its supervision that the licensee assumes its responsibility.

Last year, STUK carried out 16 inspections of Fortum Power and Heat Oy’s (Fortum) nuclear power plant in Loviisa in accordance with the operational inspection programme. Inspections were carried out at the plant site and as a combination of remote and on-site inspections, as so-called hybrid inspections. 

Fortum carried out a so-called short annual maintenance for both units of the nuclear power plant at the beginning of autumn 2023. During the annual maintenance, special attention is paid to radiation safety, as work is carried out in places that are not accessible during normal operations of the plant due to radiation. The annual maintenance work was carried out safely and the radiation doses of those involved in the maintenance work remained low.

At the beginning of 2023, STUK issued its statement on the continued operation of the Loviisa nuclear power plant units until 2050. In its statement, STUK stated that Fortum has taken care of the safety of the Lovisa 1 and 2 nuclear power plant units in accordance with the regulations in force. According to STUK's assessment, Fortum also has the necessary prerequisites, procedures, expertise and resources to continue to operate safely and to manage the ageing of the plant. The permit for continued use was granted by the Government in February 2023. 

"Fortum’s new permit has been reflected in STUK’s monitoring work: we make sure that all matters at the plant are in order in terms of service life management and the plans for interim storage of spent fuel for additional years are clear. We also wanted to get a clear picture of Fortum's modification work management, as with the new permit, Fortum will be initiating extensive renovations in the coming years to ensure that the plant’s safe service life will continue from 2030 to 2050. We will continue with these monitoring priorities at STUK in 2024," says Project Manager Tomi Koskiniemi.

The commissioning phase of Olkiluoto 3 successfully completed

During the past year, STUK carried out a total of 20 inspections in accordance with the inspection programme for Teollisuuden Voima Oyj’s (TVO) Olkiluoto nuclear power plant. Olkiluoto’s first and second units underwent annual maintenance in spring 2023. Approximately 30 experts from the Radiation and Nuclear Safety Authority (STUK) supervised the annual maintenance. According to STUK's control findings, the annual maintenance was carried out safely.

STUK continued to monitor the commissioning phase power tests of the Olkiluoto 3 plant unit. The commissioning tests carried out on the plant were successful as a whole from the point of view of nuclear safety. After commissioning, the plant started to produce electricity on a regular basis in April 2023. STUK followed the first operating period of the Olkiluoto 3 
plant unit, and no such significant deviations in the plant’s operational safety were found which would have had an immediate impact on safety.

"During 2023, a significant milestone was reached for the Olkiluoto 3 plant and its supervision, when the trial runs were successfully completed and regular electricity production started. Now monitoring continues in the same way as at other nuclear power plants in Finland," says Project Manager Essi Vanhanen from STUK.

Environmental monitoring near power plants

The nuclear power companies are responsible for the safety of the nuclear power plants. The power companies also monitor the radiation and radioactive substances in the power plant environment. STUK’s supervision complements and verifies the companies’ own environmental monitoring.

STUK monitors the radiation situation of the environment by collecting samples from the land and sea environment as well as outdoor air near the power plants. STUK also monitors the levels of radioactive substances in people living in the vicinity of the power plants.

STUK’s monitoring report "Ydinvoimalaitosten ympäristön säteilyvalvonta Suomessa 2023" (Radiation monitoring of nuclear power plant environment in Finland 2023) will be published in early summer 2024.

Read more about supervision of nuclear safety