*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. 
- From 3:37 pm on March 25, we started injecting freshwater by a motor 
  driven pump which is now powered by the off-site transmission line. 
  Water is currently injected at approx. 3.6 m3/h through reactor feed 
  water system piping arrangement. 
- We commenced injection of nitrogen gas into Primary Containment Vessel at 
  1:31am on April 7. 
- At 9:00 am on August 10, we started to assemble steel frame for the 
  Reactor Building Cover. 
- At 11:22 pm 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. 
 
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. 
- From 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 the reactor feed water system piping 
  arrangement. 
  Water is currently injected at approx. 4 m3/h through reactor feed water 
  system piping arrangement, and at approx. 1 m3/h through core spray 
  system water injection piping arrangement. 
- From 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. 
 
Unit 3 (Shut down) 
- Explosive sound and white smoke were confirmed at approximately 11:01am 
  on March 14. It was assumed to be hydrogen explosion. 
- From 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. 
- From 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. 4 m3/h through reactor feed water 
  system piping arrangement, and at approx. 3 m3/h through core spray 
  system water injection piping arrangement. 
- From 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. 
 
Unit 4 (Outage due to regular inspection) 
- At approximately 6 am on March 15, we confirmed the explosive sound and 
  the sustained damage around the 5th floor rooftop area of Reactor 
  Building. 
- From 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. 
- From 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 time, 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 3:12 pm on September 10, we started cooling the spent fuel pool 
  through the Residual Heat Removal System A using the seawater pump C. We 
  will conduct cooling the reactor and the spent fuel pool by turn through 
  the System A. 
- 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 8:00 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 10:00 am on September 11, we started transferring accumulated water 
  from the turbine building of Unit 3 to the High Temperature Incinerator 
  Building of Centralized Radiation Waste Treatment Facility. After the 
  temporary interruption for the confirmation of the system constitution, 
  we changed the transfer route and started transferring to Process 
  Building of Centralized Radiation Waste Treatment Facility. 
- At 9:51 am on September 13, we started transferring accumulated water 
  from the turbine building of Unit 2 to High Temperature Incinerator 
  Building of Centralized Radiation Waste Treatment Facility. 
- At 3:58 am on September 13, we stopped the cesium absorption instrument 
  and the decontamination instrument for the maintenance of the water 
  treatment facility. Then, after the completion of the maintenance work, 
  we restarted the treatment of the accumulated water at 7:20 pm on 
  September 14. 
- At 9:53 am on September 14, we started transferring accumulated water at 
  Unit 1 condenser to the basement of Unit 1 turbine building. 
- At 11:8 am on September 14, we stopped the operation of cooling 
  facilities of common pool because the common pool power center will be 
  moved with the replace of power panel located at the basement of the 
  spent fuel common pool's building. 
- At approximately 12:40 pm on September 14, we found the inside of 
  full-face masks, which were used by 4 out of 6 partner company workers, 
  contaminated when we were checking the contamination of the masks used in 
  maintenance work of the water treatment system. Then, as a result of the 
  measurement by whole body counter, we have confirmed that no one took in 
  radioactive materials. 
- At approximately 4 pm on September 14, a TEPCO employee who returned from 
  the patrol on the generators of Unit 1 - 4 (outdoors) to Visitors Hall of 
  Fukushima Daini Nuclear Power Station got decontaminated since 
  contamination at his chin and neck was detected. Then as a result of the 
  measurement by whole body counter, we have evaluated that no radioactive 
  materials was taken in. 
- At approximately 8:18 am on September 15, we found a partner company 
  worker unequipped with a charcoal filter to the full-faced mask after the 
  worker entered the site of Fukushima Daiichi Nuclear Power Station. We 
  will check by whole body counter if he took in radioactive materials. 
- At 10 am on September 15, we started transfer of accumulated water from 
  the turbine building of Unit 6 to the temporary tank.