Tokyo Electric Power Co. decommissioned the No. 5 and No. 6 reactors at its meltdown-stricken Fukushima No. 1 nuclear plant in Fukushima Prefecture on Friday.
The two units were the only ones that survived the Great East Japan Earthquake and subsequent tsunami that hit the aging six-reactor plant in March 2011.
Tepco, as the utility is known, will now focus on containing the vast volumes of radioactive water building up and leaking from the plant, which was heavily damaged by the offshore quake and tidal waves. The decommissioning work is expected to take 30 to 40 years to complete.
Reactors 1 to 3, which were hit by core meltdowns, were decommissioned in April 2012 along with reactor 4, which was damaged by adjacent explosions and was the main repository for the plant’s fuel rods.
After Prime Minister Shinzo Abe pressured Tepco President Naomi Hirose in September last year to decommission the No. 5 and No. 6 reactors, the utility decided in December to retire them and notified trade and industry minister Toshimitsu Motegi.
The utility plans to use No. 5 and No. 6 as research facilities for developing decommissioning technologies because they were basically intact compared with the other four reactors.
With the decommissioning of No. 5 and No. 6, the number of reactors run by Tepco fell to 11 in total: seven at its giant Kashiwazaki-Kariwa plant in Niigata Prefecture and four at the Fukushima No. 2 plant.
As a result, Japan now has a total of 48 commercial reactors. All are currently idle due to the widespread nuclear safety concerns raised by the Fukushima disaster.
The crippled No. 1 reactor was Tepco’s first and came online in March 1971.
The Fukushima No. 1 plant generated a total of 934 billion kilowatt-hours of electricity, which is equivalent to more than three years of power sold by Tepco.