*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 amount from the reactor feed water system is 
  approx. 4.3 m3/h and that from the core spray system is approx. 1.8 m3/h. 
- 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 
  feed water system, we started water injection from piping of core spray 
  system to the reactor. 
  Because the tendency of temperature rise at the bottom of PCV had been 
  accelerated since February 2, we increased the amount of water injected 
  to the reactor and continued monitoring the tendency of the temperature 
  fluctuation. 
- 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 
  control system started. 
  On February 15, sampling for the air of the PCV gas control system was 
  conducted. As a result of the analysis, it was confirmed that xenon 135 
  at the entrance of the system was below the detection limit 
  (1.0X10-1Bq/cm3) and recriticality criteria 1 Bq/cm3. 
- 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 amount from the reactor feed water system is 
  approx. 2.9 m3/h and that from the core spray system is approx. 6.1 m3/h. 
  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. 
  Since 9:50 am on February 10, we have conducted the work to add flow 
  meters to the nitrogen injection line at the side of Primary Containment 
  Vessel of Unit 3 in order to improve the reliability of nitrogen 
  injection activity. During this period, due to this work, we suspended 
  the nitrogen injection task temporarily. 
- 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. 
- 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. 
- In order to conduct inspection of the strainer changeover valve of the 
  pump of the reactor sea water system of Unit 6 from February 14 to 
  February 17, at 10:02 am on February 14, we stopped cooling of the spent 
  fuel pool by the spent fuel pool cooling system (B) and at 10:06 am on 
  the same day, we stopped the pump of the reactor sea water system (A) 
  (spent fuel pool water temperature during the stoppage: approx. 23°C). 
  Because the spent fuel pool cooling system isn't in operation during the 
  inspection, we conduct alternating cooling of the reactor and the spent 
  fuel pool by the residual heat removal system. The water temperature in 
  the reactor and the spent fuel pool are expected to rise up to 37°C and 
  31°C respectively during the inspection, but in terms of the temperature 
  raise, we estimate that it is not a problem. 
- 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 accumulated water containing radioactive materials was found in the 
  trench between Process Main Building and Miscellaneous Solid Waste 
  Volume Reduction Treatment Building (High Temperature Incinerator 
  Building) in Centralized Radiation Waste Treatment Facility (December 18, 
  2011), inspection of other trenches in the site was commenced from 
  January 11. As of the last inspection on February 15, the inspection of 
  trenches etc. were completed. 
  The inspection done on February 15, the result (quick estimation) of 
  inspection is as follows(place and nuclide analysis): 
 - Inside of fire extinction pipe trench(East of Unit 3) 
   I-131: Below the detection limit, Cs-134: 3.4X100Bq/cm3, 
   Cs-137: 4.8X100Bq/cm3 
 - Inside Unit 5 and 6, Transformer disaster prevention pipe trench 
   I-131: Below the detection limit, Cs-134: 1.0X10-1Bq/cm3, 
   Cs-137: 9.3X10-2Bq/cm3 
 - Fire extinction pipe trench(Southwest of Unit 5) 
   I-131: Below the detection limit, Cs-134: 1.4X10-1Bq/cm3, 
   Cs-137: 1.6X10-1Bq/cm3 
- At 9:18 am on January 31, we started transfer of Sub-drain Water of Unit 
  6 to the temporary tank. We will conduct transferring to the temporary 
  tank appropriately. 
- At 2:43 pm on February 10, we started to transfer accumulated water from 
  underground floor of turbine building of Unit 2 to centralized radiation 
  waste treatment facility (Miscellaneous Solid Waste Volume Reduction 
  Treatment Building [High Temperature Incinerator Building]). 
- From 9:57 am on February 12 to 9:50 am on February 16, we completed to 
  transfer accumulated water in the underground of turbine building of 
  Unit 3 to the Centralized Radiation Waste Treatment Facility (Process 
  Main Building). 
- From 10:00 am to 4:00 pm on February 15, we transferred accumulated 
  water at the basement of turbine building of unit 6 to temporary tank. 
- At around 8:30 pm on February 15, we detected radiation from a face of a 
  worker of co-operating company who was collecting and delivering debris 
  at around the Unit 3 and the Solid Waste Storage Facility No1 and 2 by 
  the contamination test at J-Village. After the decontamination of the 
  face, we conducted the contamination test again by whole body counter. 
  As a result, no radioactive materials was taken in(below 2mSv). We 
  evaluated that the radiation was attached when he removed the equipment, 
  because there were no other workers who were detected the radiation at 
  the area and no defects of the equipment situation.