*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.
  At 7:03 pm on November 24, the injection amount by the feed water system 
  decreased from 5.5 m3/h to 5.0 m3/h to lower the hydrogen density of RPV 
  by increasing the temperature and the steam ratio thereby. 
  The current water injection volume is approx 5 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.
  At 7:11 pm on November 24, in order to lower the hydrogen density of RPV 
  by increasing the temperature and the steam ratio thereby, the water 
  injection amount by the reactor core system decreased from 7.2 m3/h to 
  5.6 m3/h (the injection of feed water system is continuing at 2.9 m3/h) 
  Water is currently injected at approx. 2.8 m3/h through reactor feed
  water system piping arrangement, and at approx. 5.5 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. 
  At 7:19 pm on November 24, in order to lower the hydrogen density of RPV 
  by increasing the temperature and the steam ratio thereby, the water 
  injection amount by the reactor core system decreased from 8.5 m3/h to 
  6.7 m3/h. (the injection of feed water system is continuing at 2.3 m3/h). 
  At 7:09 pm, as the amount of nitrogen included was smaller than that of 
  Units 1 and 2, the amount increased from 14 m3/h to 28.5 m3/h. 
  Water is currently injected at approx. 2.1 m3/h through reactor feed
  water system piping arrangement, and at approx. 6.8 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. 

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. (Hydrazine was also injected from 1:31 pm
  to 3:05 pm on November 24)
- 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.
- From November 15, we started to cleanup work in order to prevent
  performance deterioration of pump caused by inletting sand or other
  materials piled up at the bottom of pump room of intake channel.
  On November 23, we finished all of this clean up work. At around 5:00 pm
  on the same day, when we restarted pump of auxiliary cooling sea water
  system (A) which was stopped due to the work, it was shut down
  automatically right after it was restarted. On November 24, as a result 
  of checkups of the pump except for the power panel switchgear that we 
  are unable to check without overhauling, since we identified no 
  abnormality, the pump resumed at 4:19 pm after a workout to resume by 
  replacing the power panel switchgear. After that at 4:35 pm, as there 
  was no abnormality we resumed cooling down the Spent Fuel Pool water by 
  using the pump (SFP water temperature: 23.5 °C at the time of resumption). 
  Since 10:23 am on November 24, as for the water residual heat removal 
  system (A) pump that has been shutdown to cool down the water of nuclear 
  reactor, we resumed operation by changing our operating method at 4:45 
  pm, (nuclear reactor water temperature: 33.4 °C at the time of 
  resumption).  
- At this moment, we do not think there is any reactor coolant leakage
  inside PCV. 

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 9:10 am on November 10, we started transfer of accumulated water from
  the basement of Unit 2 turbine building to Centralized Radiation Waste
  Treatment Facility High Temperature Incinerator Building.
- At 9:25 am on November 15, we started transfer of accumulated water from
  basement of Unit 3 turbine building to Centralized Radiation Waste
  Treatment Facility Building.
- From 9:31 am to 5:05 pm on November 24, we transferred water from
  On-site Bunker Building to Centralized Radiation Waste Treatment
  Facility Process Building.