*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.
  The Current water injection volume is approx. 4.5 m3/h from the reactor 
  feed water system and approx. 1.8 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.
  At 10:04 am on January 22, we adjusted the water injection rate to the  
  reactor in order to switch the water injection piping for reactor  
  injection pump on the hill gradually. We kept the amount of water  
  injection through the reactor feed water system at approx. 6.0 m3/h and  
  adjusted the amount of water injection through the core spray system  
  from approx. 3.9 m3/h to 3.0 m3/h.  
  The Current water injection volume is approx. 6.0 m3/h from the reactor 
  feed water system and approx. 3.0 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.
- At 11:50 am on January 19, 2012, we started the operation of the spent 
  fuel pool desalting facility. 

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.
  The Current water injection volume is approx 5.1 m3/h from the reactor 
  feed water system and approx. 3.8 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 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.
- At 3:18 pm on January 14, we started operation of the radioactive 
  material removal instrument for the spent fuel pool in Unit 3 

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 (from 1:30 pm to 3:14 pm on January 12, 
  2012, we injected hydrazine [corrosion inhibitor] in conjunction with 
  the cyclic cooling).
- 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. 

Others 
- At around 10:00 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 8:00 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.
- As finding of accumulated water containing 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. 
- From 3:37 pm on January 20 to 10:03 am on January 22, we transferred 
  accumulated water from the basement, T/B, Unit 1 to the basement, T/B, 
  Unit 2.
- At 3:23 pm on January 20, we started transferring accumulated water from 
  the basement of T/B, Unit 2 to the Central Radioactive Waste Treatment 
  Facility (Miscellaneous Solid Waste Volume Reduction Treatment Building 
  [High Temperature Incinerator Building]).
  At 7:02 am on January 21, a worker from the cooperating company found 
  water leakage from the transfer piping at the large equipment hatch, T/B, 
  Unit 4.
  We checked the work site and observed water leakage from a flange of the 
  piping to a valve unit. Part of water dripped to the floor outside of 
  the valve unit. At 7:48 am on the same date, we stopped the transfer 
  pump for the accumulated water. At 7:55 am, we confirmed that the 
  dripping of water stopped. The water was within the T/B and there was no 
  leakage to outdoor, no leakage to the sea. The volume of water dripped 
  to the floor of T/B was approx 2 liters. The surface dose rate was 
  0.1mSv/h. We believe that this was not high density contaminated water. 
  The location of the leak was at a flange of newly installed piping. 
  After installation of the piping, we checked leakage using water at the 
  vertical pit, Unit 1*. We estimate that that water was pushed out and 
  dripped to the floor. After that, from 1:58 pm to 2:49 pm, we conducted 
  flushing of the transfer piping and confirmed that there was no leakage. 
  We will change the hose hereafter. Regarding the cause of the leakage, 
  we estimate that shielding material over the hose became load to the 
  connection part and it lost the sealing characteristics, and then it 
  reached leakage. The shielding material over the hose was removed. On  
  January 22, after we conducted replacement of the hose and leakage check,  
  at 2:33 pm, we started transferring accumulated water to the Central  
  Radioactive Waste Treatment Facility (Miscellaneous Solid Waste Volume  
  Reduction Treatment Building [High Temperature Incinerator Building]).  
  * water at the vertical pit, Unit 1: we estimate that this was a mixture 
    of seawater and rainwater. The measurement result on January 14 was as 
    below:
    (I-131: below detectable limit [1.7X10-2Bq/cm3], 
     Cs-134: 1.8X10-1Bq/cm3, Cs-137: 2X10-1Bq/cm3)
- From 3:17 pm on January 20 to 2:18 pm on January 21, we transferred 
  accumulated water from the basement of T/B, Unit 3 to the Central 
  Radioactive Waste Treatment Facility (Miscellaneous Solid Waste Volume 
  Reduction Treatment Building [High Temperature Incinerator Building]). 
  As water leakage occurred on the piping for transferring accumulated 
  water from the basement of T/B, Unit 2 to the Central Radioactive Waste 
  Treatment Facility (Miscellaneous Solid Waste Volume Reduction Treatment 
  Building [High Temperature Incinerator Building]), we started checking 
  similar flanges to confirm leakage. At 2:30 pm, we found seepage at one 
  location (without water dripping). We will change the hose after 
  flushing of the transfer piping. Regarding the cause of the seepage, we 
  estimate that shielding material over the hose became load to the 
  connection part and it lost the sealing characteristics, and then it 
  reached seepage. The shielding material over the hose was removed. From  
  0:07 pm to 0:40 pm on January 22, we conducted flushing, and after  
  replacement of the hose and leakage check, at 2:30 pm, we started  
  transferring accumulated water to the Central Radioactive Waste  
  Treatment Facility (Miscellaneous Solid Waste Volume Reduction Treatment  
  Building [High Temperature Incinerator Building]).