World’s first small nuclear plant may be built next to a home in Kuopio

Kuopio may become home to the world’s first commercial small nuclear plant designed solely to produce district heating, with a home less than 300 metres from the planned site.

Yle reports that Kuopio Energia, the city’s energy utility, has signed a preliminary feasibility agreement with Steady Energy, a Finnish start-up developing what it calls the world’s first commercial district-heating nuclear reactor. The existing Haapaniemi biomass plant, which supplies both heat and electricity, is due to reach the end of its operational life in 2035, leaving district heating without a dedicated source.

Steady Energy’s light-water reactor would have an output of 50 MW; Kuopio Energia envisions installing two units for a total of 100 MW. The plant would be built underground in a rock cavern, with used fuel stored on site. A second potential supplier, France’s Calogena, offers a smaller 30 MW unit.

Kuopio Energia is also exploring small nuclear options in Helsinki, Jyväskylä and Kerava, but the project is most advanced in Kuopio, where Steady Energy estimates a two-reactor plant would cost about €200 million. Possible sites include Sorsasalo in the north and Hepomäki in the south; both are near Kallavesi, the lake from which Kuopio draws its drinking water.

The Finnish Radiation and Nuclear Safety Authority (STUK) eased rules in 2024 by removing fixed distance requirements for nuclear plants, allowing case-by-case safety assessments instead. STUK has already conducted an international review of Steady Energy’s design and found the concept appropriate, though substantial additional work is still needed before a construction licence can be sought, likely around 2028.