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Home  /  PRODUCTION  /  Plant units  /  OL1 and OL2


The nuclear power plant units Olkiluoto 1 and Olkiluoto 2 (OL1 and OL2) plant units are identical: they are boiling water reactors. The current net electrical output of OL1 is 890 megawatts (MW) and that of OL2 is 890 MW. OL1 was first connected to the national grid in September 1978 and OL2 followed in February 1980.

TVO systematically modernizes the OL1 and OL2 plant units during annual outages and modernization projects. Read more about annual outages


Plant units operated safely for the entire year

The combined power output of OL1 and OL2 was 14,089 GWh in 2018. The combined load factor of the plant units was 91.1%. TVO produced in Olkiluoto approximately 16% of all the electricity consumed in Finland.

The plant units operated safely. The net output of OL1 was 6,755 GWh and the load factor was 87.8%. The net output of OL2 was 7,334 GWh and the load factor was 94.3%.

Production diagrams

Annual production 2016

Unplanned automatic reactor trips per 7,000 criticality hours
2016: 0.0
2017: 0.0
2018: 1.3

Uranium as a fuel

The OL1 and OL2 plant units require an annual total of about 40 tonnes of low-enriched uranium for fuel. TVO acquires its fuel through a decentralized supply chain with several suppliers for each stage of the chain.

TVO has long-term contracts with leading uranium suppliers which TVO monitors and assesses on a continuous basis. Uranium is only acquired from suppliers who meet the strict requirements specified by TVO. Read more about uranium.