*Updates are underlined 

All 6 units of Fukushima Daiichi Nuclear Power Station have been shut down. 

Unit 1 (Shut down) 
- Explosive sound and white smoke were confirmed after the big quake 
  occurred at 3:36 pm on March 12. It was assumed to be hydrogen explosion.
- At approximately 2:30 am on March 23, seawater injection to the reactor 
  through the reactor feed water system was initiated.
- From 3:37 pm on March 25, we started injecting freshwater by a motor 
  driven pump powered by the off-site transmission line. We are now 
  injecting freshwater by a motor driven pump powered by the off-site 
  transmission line. At 10:02 am on June 21 we changed the rate of water 
  injection to the reactor from approx. 4.5m3/h to approx. 4.0m3/h through 
  reactor feed water system piping arrangement. Water is currently injected
  at approx. 4 m3/h through reactor feed water system piping arrangement.
- As it was suspected that hydrogen gas had been accumulated inside Primary
  Containment Vessel, in order to prevent increase in density of oxygen, we
  commenced the valve opening operation concerning injection of nitrogen 
  gas into the primary containment vessel at 10:30 pm on April 6 and 
  commenced injection at 1:31am April 7.
  At 11:55 am on June 21 we temporarily stopped operating the nitrogen 
  supply equipment to Unit 1 Primary Containment Vessel due to work of 
  power supply for alternative cooling equipment of Unit 1 spent fuel pool 
  cooling and filtering system. 

Unit 2 (Shut down) 
- At approximately 6:00 am on March 15, an abnormal noise began emanating 
  from nearby Pressure Suppression Chamber and the pressure within the 
  chamber decreased. 
- From 10:10 am on March 26, we started injecting freshwater to the reactor
  and are now injecting freshwater by a motor driven pump powered by the 
  off-site transmission line. 
  At 10:04 am on June 21 we changed the rate of water injection to Unit 2 
  Reactor from approx. 5 m3/h to approx. 4.5m3/h through reactor feed water 
  system piping arrangement. Water is currently injected at approx. 
  4.5m3/h through reactor feed water system piping arrangement. 

Unit 3 (Shut down) 
- Explosive sound and white smoke were confirmed at approximately 11:01am 
  on March 14. It was assumed to be hydrogen explosion.
- From 6:02 pm on March 25, we started injecting fresh water to the reactor
  and are now injecting fresh water by a motor driven pump powered by the 
  off-site transmission line.
  At 10:06 am on June 21 we changed the rate of water injection to Unit 3 
  Reactor from approx. 11 m3/h to approx. 10 m3/h through reactor feed 
  water system piping arrangement. Water is currently injected at approx. 
  10 m3/h through reactor feed water system piping arrangement. 

Unit 4 (Outage due to regular inspection) 
- At approximately 6:00 am on March 15, we confirmed the explosive sound 
  and the sustained damage around the 5th floor rooftop area of Reactor 
  Building.
- At this moment, we do not consider any reactor coolant leakage inside the
  primary containment vessel has occurred. 

Unit 5 (Outage due to regular inspection) 
- Sufficient level of reactor coolant to ensure safety is maintained.
- At 5:00 am on March 19, we started the Residual Heat Removal System Pump 
  (C) in order to cool the spent fuel pool.
- At 2:30 pm on March 20, the reactor achieved cold shutdown. 
- At this moment, we do not consider any reactor coolant leakage inside the
  primary containment vessel has occurred. 

Unit 6 (Outage due to regular inspection) 
- Sufficient level of reactor coolant to ensure safety is maintained.
- At 10:14 pm on March 19, we started the Residual Heat Removal System Pump
  (B) of Unit 6 in order to cool the spent fuel pool.
- At 7:27 pm on March 20, the reactor achieved cold shutdown. 
- At this moment, we do not consider any reactor coolant leakage inside the
  primary containment vessel has occurred. 

Operation for cooling the spent fuel pools 
- At 5:21 pm on May 31, we started cyclic cooling of the spent fuel pool in
  Unit 2 using alternative cooling system for fuel pool cooling and 
  filtering system. 
- We will continuously conduct further water spray depending on the 
  conditions of spent fuel pools, if needed. 

Others 
- At 1:30 pm on April 26, we started spraying the dust inhibitor inside the
  site. 
- At 2:00 pm on May 1, we started transferring accumulated water in the 
  turbine building of Unit 6 to temporary tanks.
- At 11:00 am on May 10, we started transferring accumulated water from the
  underground level of reactor building to the radiation waste treatment 
  facility of Unit 6.
- At 12:42 pm on June 11, we started to operate local exhausters in order 
  to improve inside environment of Unit 2 Reactor Building. At 8:51 pm on 
  June 19, we slightly opened the airlock of the reactor building, and at 
  5:00 am on June 20 we fully opened it. At 2:30 pm on the same day we 
  opened the truck bay door of the reactor building. We confirmed a 
  monitored result of dose rate in the air and confirmed that there was no 
  external impact.
- At approximately 10:00 am on June 13, we started the operation of the 
  circulating seawater purification facility installed at the screen area 
  of Unit 2 and 3.
- At 2:20 pm on June17, we started transferring accumulated water in the 
  vertical shaft (trench) of the turbine building of Unit 2 to the 
  condenser in the turbine building of Unit 1. However, at 2:59 pm we 
  stopped the operation of the transfer pump since water flux was not 
  observed. The transfer pump that we had confirmed did not properly work 
  was switched to other ones and we resumed transfer of accumulated water 
  at 1:37 pm on June 20.
- From 8:00 pm on June17, we started operation of water treatment of 
  accumulated water at accumulated water treatment facility. At 12:54 am on
  June18, we stopped operation of the facility temporarily due to the 
  radiation dose at surface level measured up to the basis of exchange 
  filter of Cesium adsorption Instruments.
- At 9:49 am on June 20, we started fresh water injection to the reactor 
  wells and pools for temporary storage of equipments of Unit 4 and Unit 5,
  in order to improve the working environment (to reduce radiation dose) on
  the 5th floor of the reactor building of Unit 4 and Unit 5.
- We will continue to take all measures to ensure the safety and to 
  continue monitoring the surrounding environment around the power station.