In total, the station has 6 boiling water reactors which together have a power generation capacity of 4.69 GW.
Fukushima Daichi was the 1st nuclear plant to be constructed and operated entirely by Tokyo Electric Power Company (TEPCO).
Following a major earthquake, a 15-metre tsunami disabled the power supply and cooling of 3 Fukushima Daiichi reactors, causing a nuclear accident beginning on 11 March 2011.
All 3 cores largely melted in the 1st 3 days.
The earthquake measured 8.9 on the Richter magnitude scale, which was much more than the plant’s bearing capacity.
The reactors proved robust seismically, but vulnerable to the tsunami.
As a result of the accident large amounts of radioactive substances were released into the environment.
On April 12 nuclear regulators elevated the severity level of the nuclear emergency from 5 to 7 - the highest level on the scale created by the IAEA - placing it in the same category as the Chernobyl accident.
Apart from cooling, the basic ongoing task was to prevent release of radioactive materials, particularly in contaminated water leaked from the 3 units.
There have been no deaths or cases of radiation sickness from the nuclear accident, but over 100,000 people were evacuated from their homes as a preventative measure.
In the long term, the operator, TEPCO, plans to recover the reactor cores part of which have melted and of the fuel elements in the fuel pools and to dispose of them.
Subsequently the plant is to be dismantled.
From November 2013 to December 2014, the fuel elements in the fuel pools of unit 4 were recovered.
In units 1 and 3 recovery of fuel elements is planned to start in 2017 after preparatory work like removal of debris and the erection of a housing have been completed.
Since the reactor cores melted according to analysis entirely or partially in blocks 1 to 3, conventional methods for the recovery of the nuclear fuel from the damaged reactors can be used only with difficulty.
An exact timing has not yet been announced by TEPCO.
According to current estimates the total decommissioning will last about 30 to 40 years.
