*The 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, 2011. It was assumed to be hydrogen
  explosion.
- At 3:37 pm on March 25, 2011, we started injecting freshwater to the
  reactor and are now injecting fresh water by a motor driven pump
  powered by the off-site transmission line. 
- At 10:11 am on December 10, 2011, in addition to water injection from
  water feeding system, we started water injection from piping of core
  spray system to the reactor.
  Current water injection volume is approx. 4.6 m3/h from the reactor
  feed water system and approx. 1.6 m3/h from the core spray system.
- At 1:31 am on April 7, 2011, we commenced injection of nitrogen gas
  into Primary Containment Vessel.
- At 11:22 am on August 10, 2011, we started cyclic cooling for the water
  in the spent fuel pool by an alternative cooling equipment of the Fuel
  Pool Cooling and Filtering System. 
- On October 28, 2011, we completed installation of the cover for the
  Reactor Building in order to contain dispersion of radioactive
  substances.
- At 4:04 pm on November 30, 2011, we started operation to inject
  nitrogen into the reactor pressure vessel.
- At 6:00 pm on December 19, 2011, a full-scale operation of the PCV gas
  management system started. 

Unit 2 (Shut down) 
- At approximately 6:00 am on March 15, 2011, an abnormal noise began
  emanating from nearby Pressure Suppression Chamber and the pressure
  within the chamber decreased. 
- At 10:10 am on March 26, 2011, we started injecting freshwater to the
  reactor and are now injecting fresh water by a motor driven pump
  powered by the off-site transmission line.
- At 2:59 pm on September 14, 2011, in addition to water injection from
  water feeding system, we started water injection from piping of core
  spray system to the reactor.
  Current water injection volume is approx. 2.8 m3/h from the reactor
  feed water system and approx. 7.1 m3/h from the core spray system.
- At 5:21 pm on May 31, 2011, we started cyclic cooling for the water in
  the spent fuel pool by an alternative cooling equipment of the Fuel
  Pool Cooling and Filtering System. 
- At 8:06 pm on June 28, 2011, we started injecting nitrogen gas into the
  Primary Containment Vessel.
- At 6:00 pm on October 28, 2011, a full-scale operation of the PCV gas
  management system started. 
- At 10:46 am on December 1, 2011, we started the nitrogen injection to
  the Reactor Pressure Vessel. 

Unit 3 (Shut down) 
- Explosive sound and white smoke were confirmed at approximately 11:01
  am on March 14, 2011. It was assumed to be hydrogen explosion.
- At 6:02 pm on March 25, 2011, 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 2:58 pm on September 1, 2011, we started water injection by core
  spray system in addition to water injection by the reactor feed water
  system piping arrangement. 
  Current water injection volume is approx 0.8 m3/h from the reactor feed
  water system and approx. 8.1 m3/h from the core spray system.
- At 7:47 pm on June 30, 2011, we started cyclic cooling for the water in
  the spent fuel pool by an alternative cooling equipment of the Fuel
  Pool Cooling and Filtering System.
- At 9:35 am on January 12, we stopped the Unit 3 spent fuel pool  
  alternative cooling system in order to install a radioactive materials 
  removal equipment in the Unit 3 spent fuel pool (the temperature of the 
  spent fuel pool at the time of the stoppage: approx. 12.7°C). As the 
  estimated increase of the temperature is 0.22°C/h (the outage time: 
  approx. 4 hours 30 minutes), there is no problem regarding the 
  temperature of the spent fuel pool. 
- At 8:01 pm on July 14, 2011, injection of nitrogen gas into the Primary
  Containment Vessel started. 
- At 4:26 pm on November 30, 2011, we started operation to inject
  nitrogen into the reactor pressure vessel. 

Unit 4 (Outage due to regular inspection) 
- At around 6 am on March 15, 2011, we confirmed the explosive sound and
  the sustained damage around the 5th floor rooftop area of Reactor
  Building.
- At 12:44 pm on July 31, 2011, we started cyclic cooling for the water
  in the spent fuel pool by an alternative cooling equipment of the Fuel
  Pool Cooling and Filtering System.
- At 10:58 am on November 29, 2011, in order to decrease more salinity,
  we installed Ion exchange equipment and started the operation of such
  equipment.
- At this moment, we don't think there is any reactor coolant leakage
  inside the primary containment vessel. 

Unit 5 (Outage due to regular inspection) 
- Sufficient level of reactor coolant to ensure safety is maintained.
- At 5:00 am on March 19, 2011, we started the Residual Heat Removal
  System Pump in order to cool the spent fuel pool.
- At 2:45 pm on July 15, 2011, we started the operation of the original
  Residual Heat Removal System (System B) by its original seawater pump.
- At 10:11 am on December 22, 2011, since we finished the recovery work
  of seawater pump (System B) of equipment water cooling system, we made
  a trial run. At 11:25 am on the same day, we confirmed no abnormalities
  and restarted the operation.
- At this moment, we don't think there is any reactor coolant leakage
  inside the primary containment vessel. 

Unit 6 (Outage due to regular inspection) 
- Sufficient level of reactor coolant to ensure safety is maintained.
- At 10:14 pm on March 19, 2011, we started the Residual Heat Removal
  System Pump of Unit 6 to cool down Spent Fuel Pool.
- At 2:33 pm on September 15, 2011, we started separately cooling the
  reactor through the Residual Heat Removal System and the spent fuel
  pool through Equipment Cooling Water System and Fuel Pool Cooling
  System.
- At this moment, we do not think there is any reactor coolant leakage
  inside PCV.
- At 4:20 pm on January 11, in order to avoid the deterioration of the 
  facilities needed to maintain the stable cold shutdown and to improve 
  the high-humidity environment in the Reactor Building, we started up 
  ventilation and air-conditioning system in the building. This air 
  conditioning system inlets and outlets air by high-efficiency particle 
  filter. 

Others 
- At around 10 am on June 13, 2011, we started the operation of the
  circulating seawater purification facility installed at the screen area
  of Unit 2 and 3.
- At 8 pm on June 17, 2011, we started operation of Water Treatment
  Facility against the accumulated water. At 6:00 pm on July 2, we
  started the circulating injection cooling to inject the water, which
  was treated by the accumulated water treatment system, to the reactors
  through the buffer tank.
- At 7:41 pm on August 19, 2011, we started treatment of accumulated
  water by parallel operation of one line from the cesium adsorption
  instrument to the decontamination instrument and the other treatment
  line of the cesium adsorption instrument No.2.
- At 2:06 pm on October 7, 2011, we started to spray purified accumulated
  water brought from Unit 5 and 6 continually in order to prevent dust
  scattering and potential fire outbreaks from the cut down trees.
- On October 28, 2011, we started installation of the water proof wall at
  the sea side, in front of the existing shore protection, Units 1-4, in
  order to contain marine pollution by underground water.
- At 12:25 pm on December 13, 2011, we started the re-circulating
  operation of desalination facility (reverse osmosis membrane type) for
  the purpose of suppression of condensed water after desalination
  treatment.
- From 8:17 am on January 10 to 3:21 pm on January 11, we conducted the
  transfer of the accumulated water from the basement of the Unit 2
  turbine building to the centralized radiation waste treatment facility
  (the process main building).
- From 3:45 pm on January 11 to 8:02 am on January 12, we conducted 
  transfer of the accumulated water from the basement of the Unit 2 
  turbine building to the centralized radiation waste treatment facility 
  (the miscellaneous solid waste volume reduction treatment building [the 
  high temperature incinerator building] and the process main building). 
- From 3:39 pm on January 11 to 8:07 am on January 12, we conducted 
  transfer of the accumulated water from the basement of the Unit 3 
  turbine building to the centralized radiation waste treatment facility 
  (the miscellaneous solid waste volume reduction treatment building [the 
  high temperature incinerator building] and the process main building). 
- From 9:47 am on January 11 to 3:32 pm on the same day, in the
  centralized radiation waste treatment facility we conducted transfer of
  the accumulated water from the on-site bunker building to the process
  main building.
- At 8:58 am on December 20, 2011, we stopped the cesium adsorption
  apparatus in order to adjust the water level in the respective turbine
  buildings and the centralized radiation waste treatment facility (the
  miscellaneous solid waste volume reduction treatment building [the high
  temperature incinerator building] and the process main building).
  At 3:22 pm on January 11, we activated the apparatus. At 3:30 pm on the  
  same day, the flow rate has reached the ordinary level. 
- Because of the finding of accumulated water included radioactive
  materials at the trench between the Process Main Building and the
  Miscellaneous Solid Waste Volume Reduction Treatment Building[High
  Temperature Incinerator Building](December 18, 2011), we started the
  inspection of other trenches at the site on January 11.
  As a result of the inspection of January 11, the locations where 
  accumulated water was discovered and the nuclide analysis results are 
  as follows: 
  · The Unit 2-4 DG connecting duct 
    I-131: below measurable limit, Cs-134: approx. 1.9×100Bq/cm3, 
    Cs-137: approx. 2.6×100Bq/cm3 
  · The accumulated water treatment building - the connecting duct in the 
    Unit 1 turbine building  
    I-131: below measurable limit, Cs-134: approx. 8.8×10-1Bq/cm3, 
    Cs-137: approx. 1.3×100Bq/cm3