Finnish small nuclear power developer Steady Energy has secured a loan of €10.5m ($12.1m) from Business Finland to finance its test facility, construction of which is currently under way in Salmisaari, Helsinki. This state-backed financing covers more than half of the estimated €15–€20m budget required to construct its full-scale pilot facility.
The Salmisaari Pilot Plant is being built inside the former turbine hall of the decommissioned Salmisaari B coal-fired power plant in central Helsinki. Construction began following a lease agreement with energy firm Helen Ltd, with operations scheduled to begin in spring 2027.
The test reactor stands 10 metres tall, matching the physical layout of the intended commercial units. For the safety and validation tests, the reactor’s uranium core will be replaced with electric heating elements. The heat generated during these extensive safety and operational tests will not be wasted; it will be fed directly into Helen Ltd’s Helsinki district heating network.
This test facility will mathematically and physically verify safety systems under real-world conditions, preventing the lengthy licensing delays and cost overruns historically associated with standard nuclear projects. The pilot serves as the final rehearsal before deploying the LDR-50, a shipping-container-sized, 50 MW thermal reactor designed by the VTT Technical Research Centre of Finland.
The commercial models are specifically designed to be buried underground within cities, safely and cleanly hooking into existing municipal heating grids. Steady Energy aims to break ground on its first commercial nuclear plant within three years. It has already signed preliminary agreements for 15 commercial reactors across Finnish municipalities and a cooperation agreement with the Korea District Heating Corporation (KDHC) in South Korea
“Our plant is small and probably the simplest in the world. This means we can build a full-scale unit specifically for safety testing,” said Hannes Haapalahti, Chief Technology Officer at Steady Energy. “In terms of design, our goal is to be ready to begin building the first plant within three years.”
Jussi Åkerberg, Programme Manager at Business Finland, noted: “Steady Energy’s project is precisely the kind of bold and ambitious renewal that Finland needs to build next-generation energy expertise, industrial competitiveness and exports.”
In Finland, the cities of Helsinki, Jyväskylä, Kerava and Kuopio are exploring the use of small nuclear power for district heating. In Kuopio, an environmental impact assessment and zoning are under way.
