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Onagawa

Onagawa, nuclear power plant in Japan, operates one boiling water reactor with 796 MW net installed capacity and has been in service since 1984. One more unit has its operation suspended.

Unit Onagawa 2 has been operating for 31 years, since 1995. Its 1,592 MW net are enough to supply about 5,010,000 households.

Country
Japan
Units
3
Technology
BWR
Net capacity
796 MWe
First grid connection
1984
Operator
Tohoku Electric Power
Owner
Tohoku Electric Power Co Inc
Status
Operating
Operating capacity
796 MWe
net electrical
Units
3
1 operating · 1 suspended
First start-up
1984
Onagawa
Photo: Wikimedia Commons · author and license

Units

UnitTypeModelStatusMWeMWtConstruction startGrid connectionClosureLoad factor
Onagawa 1Boiling water (BWR)BWR-4Shut down4981,593Jul 1980Nov 1983Dec 2018—
Onagawa 2Boiling water (BWR)BWR-5Operating7962,436Apr 12, 1991Dec 23, 1994—63.3 % (2024)
Onagawa 3Boiling water (BWR)BWR-5Offline, no restart pending7962,436Jan 1998May 2001——

Data: IAEA PRIS · Wikipedia · updated on Sep 17, 2026

Onagawa 1, a 498 MWe BWR (BWR-4), started construction in 1980 and operated from 1983 to 2018.

Onagawa 2, a 796 MWe BWR (BWR-5), started construction in 1991, was connected to the grid in 1994 and is still operating, with a 63.3% load factor in 2024.

Onagawa 3, a 796 MWe BWR (BWR-5), started construction in 1998, was connected to the grid in 2001 and is currently suspended.

Operator: Tohoku Electric Power.

Owner: Tohoku Electric Power Co Inc (Onagawa 1, Onagawa 2, Onagawa 3).

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