Fortum’s Loviisa nuclear power plant annual outage 2025 completed

FORTUM CORPORATION PRESS RELEASE 6.10.2025

Both units at the Loviisa nuclear power plant are back in production after completion of their annual outages. During the annual outages, about a quarter of the fuel in both units was replaced. In addition to refuelling, several preventive maintenance, servicing, and inspection tasks were carried out. 

The annual outage of the power plant’s Unit 2 was delayed by approximately 12 days and the outage was continued for some time in parallel with the outage of Unit 1. The annual outage of Unit 2 was completed on 18 September 2025. The annual outage of Unit 1 ended on 3 October 2025, about nine days late.

“Several factors contributed to the delay in the annual outage of Unit 2. These included the dropping of the control rod during fuel handling and the additional repair needs identified during inspections, testing and start-up. The delay in the annual outage of Unit 1 was mainly due to boron water leaking onto the reactor deck and the cleaning work required by it,” notes Sasu Valkamo, Senior Vice President of Loviisa power plant.

In conjunction with the annual outage of Unit 2, a defective fuel bundle was removed from the reactor and replaced with another bundle. The cause of the defect will be determined in a fuel analysis to be conducted later. 

“Safety and reliable operation is our guiding star also in annual outages. Annual outage inspections can sometimes uncover maintenance needs or defects that weren’t anticipated, potentially delaying their completion. The equipment and systems are carefully tested before the plant unit is returned to the network after the annual outage,” Valkamo emphasises.

Introduction of new fuel type is progressing as planned

In November 2022, Fortum signed an agreement with the US-based Westinghouse Electric Company for the design, licensing and supply of a new fuel type for the Loviisa power plant. The new fuel type and cooperation with Westinghouse guarantees a reliable Western alternative for fuel deliveries to the Loviisa power plant.

Fortum loaded the first batch of the nuclear fuel supplied by Westinghouse into Unit 2 during the 2024 annual outage. This year, the introduction of the new fuel continued with the loading of additional Westinghouse fuel into Unit 2. A significant amount of the fuel load at Loviisa nuclear power plant is now of Western origin. 

Annual outage ensures the continuation of stable electricity production

Annual maintenance outages support the life cycle management of the Loviisa power plant. Regular maintenance ensures safe and reliable operation of the plant throughout the next operating period and, in the long term, until the current operating licences expire.  

Extending the operating licence for the Loviisa power plant to 2050 means an investment programme worth around one billion euros. The projects included in the programme have already been launched and are progressing as planned, with some of them being advanced particularly during future annual outages. This year, among other things, the employee accommodation village located near the power plant has been renovated. During the annual outage, the high-pressure preheaters in Unit 1 were replaced, valves were replaced with new ones, and the measurement piping was renewed. In addition, preparatory work was also carried out for projects to be implemented in future annual outages.

In 2026, it will be time for extensive annual outage, which will involve starting the modernisation of the low-pressure turbines, the renewal of turbine automation, and the replacement of the main seawater pumps and motors.

Fortum Corporation 

Communications 

Further information: 

Fortum News Desk, newsdesk@fortum.com, +358 40 198 2843

Loviisa Nuclear Power Plant

In 2024, the load factor at Fortum’s fully-owned Loviisa nuclear power plant was 88.3%. In 2024, the power plant produced a total of 7.9 terawatt hours of electricity, which is more than 10% of Finland’s electricity production. Fortum employs about 700 nuclear sector professionals, 570 of them work at the Loviisa power plant. Additionally, nearly 100 permanent employees of other companies work in the power plant area every day. www.fortum.com/loviisa

Fortum 

Fortum is a Nordic energy company. We generate and deliver reliable energy to our customers and the Nordic energy system while at the same time helping industries decarbonise their processes and grow. Our core operations comprise efficient and best-in-class low-carbon power generation, customer services, and heating and cooling. Fortum’s power generation is already 99% from renewable or nuclear sources with one of the lowest specific CO2-emissions in Europe. We are guided by our ambitious SBTi-validated emission reduction targets on our way towards net-zero by 2040. For our ~4,500 employees, we commit to be a safe and inspiring workplace. Fortum's share is listed on Nasdaq Helsinki. fortum.com