*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. 
- At 5:43 am on November 9, cooling system of spent fuel pool was stopped 
  due to the switching work of electricity to enhance security of 
  electricity source. It will be shut down until 4:30 pm. The temperature 
  at the time was 22°C and the temperature of spent fuel pool will be 
  estimated to increase around 1-2°C. 
- 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 5:41 am on November 9, cooling system of spent fuel pool was stopped 
  due to the switching work of electricity to enhance security of 
  electricity source. It will be shut down until 4:30 pm. The temperature 
  at the time was 22°C and the temperature of spent fuel pool will be 
  estimated to increase about 3°C. 
- 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 9:22 am on November 9, dust sampling commenced at open mouth of 
  reactor building (blowout panel). 
 
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 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 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. Thereafter, as a result  
  of the inspection of inlet strainer of boiler make up water transfer  
  pumps (A) and (B), plugging was found due to water scale of filtered water  
  attached to inside of the pipe, after removing those contaminations,  
  evaporated concentration apparatus 3B and 3C was restarted at 5:08 pm on  
  the same day. At 4:45 am on November 9, as pressure decrease of make up  
  water transfer pump (A), operation was switched to transfer pump (B).  
  Thereafter, as pressure decrease was also observed for transfer pump (B),  
  at 9:14 am, evaporative concentration apparatus 3B, AC, at 9:16 am, make  
  up water transfer pump (B) and at 9:21 am, boiler (B) was stopped.  
- At 4:23 am on November 8, as allophone was observed from the motor of  
  cesium adsorption treatment water transfer pump (B), cesium adsorption  
  apparatus was stopped. After switched to (A) pump, at 4:54 pm, it was  
  restarted and reached to normal operation flow (approx. 18m3/h) at 5:00  
  pm. We will investigate the cause. As the apparatus stop time was short,  
  there was no significant effect on the water treatment.  
- At 10:00 am on November 9, transfer of accumulated water from turbine  
  building of unit 6 to temporary tank was started.