*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. 3.8m3/h through reactor feed water 
  system piping arrangement. 
- 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. 

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 reactor feed water system piping 
  arrangement.
  Water is currently injected at approx. 3.8 m3/h through reactor feed 
  water system piping arrangement, and at approx. 6 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 11:01 am 
  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. 2.6 m3/h through reactor feed 
  water system piping arrangement, and at approx. 8.1 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. (From 1:20 pm to 3:10 pm on September 29, 
  we started injection of hydrazine (corrosion inhibitor) in addition to 
  this.)
- 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 around 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 1:57 pm to 3:48pm on September 27, 
  we also injected hydrazine [corrosion inhibitor].)
- 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.
- From 9:45 am to 10:42 am on September 26, the B system (main) of sea 
  water pump on Residual Heat Removal System was switched to the A system 
  (temporary), in order to repair the outlet valve of the 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 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 8:00 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 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 9:54 am on September 15, we started transfer of the accumulated water 
  from the process building of Unit 3 to Centralized Radiation Waste 
  Treatment Facility. At 10:00 am on September 30, we changed to transfer 
  the accumulated water to the turbine building of High Temperature 
  Incinerator Building of Centralized Radiation Waste Treatment Facility. 
- From 10:00 am to 4:00 pm on September 29, we transferred of the 
  accumulated water from the turbine building of Unit 6 to the temporary 
  tank. At 10:00 on September 30, we started the transfer.  
- At around 10:30 am on September 29, the worker of the partner company 
  got water from the drain hose to his full-face mask, when conducting the 
  transfer of the concentrated waste water at the Water Treatment Facility. 
  Since it is assumed that the part around mouth was contaminated when 
  removing the full-face mask, decontamination was conducted by wiping. As 
  the result of the measurement of contamination inside the body of the 
  worker using the whole body counter, we have confirmed that the worker 
  did not take in any radioactive materials.