*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 3:37 pm on March 25, 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. 
  The current water injection volume is approx 7.8 m3/h from the reactor 
  feed water system. 
- We commenced injection of nitrogen gas into Primary Containment Vessel 
  at 1:31 am on April 7. 
- At 11:22 am on August 10, 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, we completed installation of the cover for the Reactor 
  Building in order to contain dispersion of radioactive substances. 
 
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. 
- At 10:10 am on March 26, 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, we started injecting water to the reactor 
  through core spray system water injection piping arrangement in addition 
  to the water injection through reactor feed water system piping 
  arrangement. 
  Water is currently injected at approx. 3 m3/h through reactor feed water 
  system piping arrangement, and at approx. 7.3 m3/h through core spray 
  system water injection piping arrangement. 
- At 5:21 pm on May 31, 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, we started injecting nitrogen gas into the 
  Primary Containment Vessel. 
- From 6:00 pm on October 28, we put the gas management system of the 
  reactor containment vessel in operation. 
- At 11:04 am on November 6, we started operation of radioactive material 
  decontamination instrument of spent fuel pool. 
 
Unit 3 (Shut down) 
- Explosive sound and white smoke were confirmed at approximately 11:01 am 
  on March 14. It was assumed to be hydrogen explosion. 
- At 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 2:58 pm on September 1, we started water injection by core spray 
  system in addition to water injection by the reactor feed water system 
  piping arrangement. 
  Water is currently injected at approx. 2.3 m3/h through reactor feed 
  water system piping arrangement, and at approx. 8 m3/h through core 
  spray system water injection piping arrangement. 
- At 7:47 pm on June 30, 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, injection of nitrogen gas into the Primary 
  Containment Vessel started. 
- At 2:30 pm on November 7, we suspended the alternative cooling in order 
  to clear clogs in the primary strainer resulted from reverse cleaning, 
  as a countermeasure against the alarm suction pressure decrease of 
  alternative primary coolant system pump in spent fuel pool of Unit 3 at 
  Fukushima Daiichi Nuclear Power Station (water temperature of spent fuel 
  pool as of suspension: approx. 24.8°C). After finishing the reverse 
  cleaning of the primary strainer, then, at 7:17 pm on the same day we 
  restarted the alternative cooling (water temperature of spent fuel pool 
  as of restart: approx. 22.5°C *It is supposed that water temperature as 
  of restart became lower than that as of suspension because water in 
  skimmer surge tank was cooled down by outside air. 
 
Unit 4 (Outage due to regular inspection) 
- At around 6 am on March 15, 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, 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 11:34 am on August 20, we started an operation of desalination 
  equipment in the spent fuel pool. 
- At 12:25 am on November 8, RO membrane unit of desalting facility in 
  spent fuel pool, Unit 4 automatically stopped due to the alarm 
  indicating leakage. Responding to the alarm, we confirmed that all the 
  isolation valves of each unit were closed by the interlocks. Also, 
  considering that all the spots at leakage risk were equipped with 
  receiving pans which would be able to store all of the liquid in the 
  unit, we judged that further deterioration of leakage or leakage to 
  outside of the unit was unlikely. We will check the site and situation 
  in the future. The operation of circulating cooling system has been 
  continued. 
- 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, we started the Residual Heat Removal System Pump 
  in order to cool the spent fuel pool. 
- At 2:30 pm on March 20, the reactor achieved cold shutdown. 
- At 2:45 pm on July 15, we started the operation of the original Residual 
  Heat Removal System (System B) by its original seawater pump. 
- 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, we started the Residual Heat Removal System 
  Pump of Unit 6 to cool down Spent Fuel Pool. 
- At 7:27 pm on March 20, the reactor achieved cold shutdown. 
- At 2:33 pm on September 15, 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 time, we don't think there is any reactor coolant leakage inside 
  the primary containment vessel. 
 
Others 
- At around 10 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 8 pm on June 17, 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, 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, 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, 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 10:11 am on November 2, we started transferring the accumulated water 
  from the basement of the Unit 3 turbine building to the High Temperature 
  Incinerator Building of the Centralized Radiation Waste Treatment 
  Facility. 
- At 9:38 am on November 4, we started transferring the accumulated water 
  from the basement of the Unit 2 turbine building to Centralized 
  Radiation Waste Treatment Facility. 
- At around 11:00 am on November 6, since partner companies' workers who 
  went on patrol found that the boiler of evaporative concentration 
  apparatus stopped, we stopped operation of the apparatus 3B and 3C. 
  Since the operation panel on the site alerted "Very low water level in 
  boiler supply water tank", we assumed that the boiler stopped due to 
  this reason. After that, we conducted investigation of the cause of 
  decrease of supply tank water level. When we started a backup pump for 
  transfer of boiler supply water, the alert stopped. Therefore we judged 
  that one pump was troubled. 
  At 2:55 pm on November 7, we started another boiler by using a spare 
  water transfer pump for boiler. Then, we started evaporative 
  concentration apparatus 3B at 5:24 pm and 3C at 6 pm. Causes of the 
  trouble of the water transfer pump for boiler are still under 
  investigation. At 2:24 am on November 8, we manually stopped the boiler 
  of evaporative concentration apparatus in the water desalinations since 
  alarm worked and indicated decrease of water level in boiler water 
  supply tank at 2:20 am. Then, we stopped evaporative concentration 
  apparatus 3B at 2:28 am ad 3C at 2:31 am. Although all the evaporative 
  concentration apparatus stopped, water treatment by the water 
  desalinations (RO membrane system) and water injection to the reactors 
  have been continued. Causes will be investigated in the future.