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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 880 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.

Kayttokerroin_eng.pngTVO 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 yearSahkontuotanto_eng.png

The combined power output of OL1 and OL2 was 13,415 GWh in 2017. The combined load factor of the plant units was 87,2%. TVO produced approximately 16% of all the electricity consumed in Finland.
The plant units operated safely. The net output of OL1 was 7,158 GWh and the load factor was 93,1%. The net output of OL2 was 6,256 GWh and the load factor was 81.3%.


Production diagrams

Weekly production
OL1: Monthly production
OL2: Weekly production
OL2: Monthly production

Annual production 2017
Annual production 2016
Annual production 2015

Unplanned automatic reactor trips per 7,000 criticality hours
2015: 0.0
2016: 0.0
2017: 0.0

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.