*The 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, 2011. It was assumed to be hydrogen 
  explosion.
- At 3:37 pm on March 25, 2011, 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 10:11 am on December 10, 2011, in addition to water injection from 
  water feeding system, we started water injection from piping of core 
  spray system to the reactor.
  Current water injection volume is approx. 4.6 m3/h from the reactor feed 
  water system and approx. 1.8 m3/h from the core spray system.
- At 1:31 am on April 7, 2011, we commenced injection of nitrogen gas into 
  Primary Containment Vessel.
- At 11:22 am on August 10, 2011, 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, 2011, we completed installation of the cover for the 
  Reactor Building in order to contain dispersion of radioactive 
  substances.
- At 4:04 pm on November 30, 2011, we started operation to inject nitrogen 
  into the reactor pressure vessel.
- At 6:00 pm on December 19, 2011, a full-scale operation of the PCV gas 
  management system started.  

Unit 2 (Shut down) 
- At approximately 6:00 am on March 15, 2011, an abnormal noise began 
  emanating from nearby Pressure Suppression Chamber and the pressure 
  within the chamber decreased. 
- At 10:10 am on March 26, 2011, 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, 2011, in addition to water injection from 
  water feeding system, we started water injection from piping of core 
  spray system to the reactor.
  Current water injection volume is approx. 2.9 m3/h from the reactor feed 
  water system and approx. 7.1 m3/h from the core spray system.
- At 5:21 pm on May 31, 2011, 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 1:38 pm on January 10, 2012, the 
  hydrazine (corrosion inhibitor) injection was also started). 
- At 8:06 pm on June 28, 2011, we started injecting nitrogen gas into the 
  Primary Containment Vessel.
- At 6:00 pm on October 28, 2011, a full-scale operation of the PCV gas 
  management system started. 
- At 10:46 am on December 1, 2011, we started the nitrogen injection to 
  the Reactor Pressure Vessel.  

Unit 3 (Shut down) 
- Explosive sound and white smoke were confirmed at approximately 11:01 am 
  on March 14, 2011. It was assumed to be hydrogen explosion.
- At 6:02 pm on March 25, 2011, 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, 2011, we started water injection by core 
  spray system in addition to water injection by the reactor feed water 
  system piping arrangement. 
  At 10:05 am on January 10, because of the replacement work of the water 
  injection piping arrangement from the water feed system in association 
  with the commissioning of reactor injection pump in Turbine Building, we 
  have controlled the amount of injected water to the reactor gradually. 
  The amount of injected water to the reactor from the reactor feed water 
  system was adjusted from approx. 3 m3/h to approx. 2 m3/h, and the 
  amount from the core spray system was adjusted from approx. 6 m3/h to 
  approx. 7 m3/h. 
  Current water injection volume is approx 2 m3/h from the reactor feed 
  water system and approx. 7 m3/h from the core spray system.
- At 7:47 pm on June 30, 2011, 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, 2011, injection of nitrogen gas into the Primary 
  Containment Vessel started. 
- At 4:26 pm on November 30, 2011, we started operation to inject nitrogen 
  into the reactor pressure vessel.  

Unit 4 (Outage due to regular inspection) 
- At around 6 am on March 15, 2011, 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, 2011, 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 10:58 am on November 29, 2011, in order to decrease more salinity, we 
  installed Ion exchange equipment and started the operation of such 
  equipment.
- 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, 2011, we started the Residual Heat Removal 
  System Pump in order to cool the spent fuel pool.
- At 2:45 pm on July 15, 2011, we started the operation of the original 
  Residual Heat Removal System (System B) by its original seawater pump.
- At 10:11 am on December 22, 2011, since we finished the recovery work of 
  seawater pump (System B) of equipment water cooling system, we made a 
  trial run. At 11:25 am on the same day, we confirmed no abnormalities 
  and restarted the operation.
- 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, 2011, we started the Residual Heat Removal 
  System Pump of Unit 6 to cool down Spent Fuel Pool.
- At 2:33 pm on September 15, 2011, 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 moment, we do not think there is any reactor coolant leakage 
  inside PCV.  

Injured and others 
- At 2:22 pm on January 9, 2012, at the Spent Sludge Storage Facility (*) 
  which is under construction, a partner company's worker who had been 
  engaged in concrete placement work reported his physical disorder. He 
  was carried to the emergency medical room of Unit 5/6 and received 
  medical treatment. Because he was in cardiopulmonary arrest, he was 
  carried from Fukushima Daiichi Nuclear Power Station to Iwaki Kyouritsu 
  Hospital at 3:25 pm. No radioactive materials were found to be attached 
  to the worker's body.

  * Spent Sludge Storage Facility: The facility to store radioactive waste 
    (spent sludge), which is produced during the process of accumulated 
    water treatment, on a temporary basis. 

Others 
- At around 10 am on June 13, 2011, 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, 2011, 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, 2011, 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, 2011, 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, 2011, 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 12:25 pm on December 13, 2011, we started the re-circulating 
  operation of desalination facility (reverse osmosis membrane type) for 
  the purpose of suppression of condensed water after desalination 
  treatment.
- From 8:17 am on January 10, 2012, we started to transfer accumulated 
  water from the basement of the turbine building of Unit 2 to the 
  Centralized Radiation Waste Treatment Facility, the Process Main 
  Building.
- At 9:25 am on January 10, second Cesium adsorption apparatus was stopped 
  to backwash the filter because there was a gradual downward tendency. At 
  12:58 pm on the same day, the apparatus was started up and it achieved 
  the steady flow (approx. 36 m3/h) at 1:04 pm. 
- At 10:28 am on January 10, TEPCO staff found a leakage of water from the 
  packing at the bottom of the tank of the concentrated water storage at 
  water desalinations (reverse osmosis membrane type), which was about one 
  drop in one second. The amount of leaked water is approx. 10 litter and 
  is staying on the concrete. After retightening of the bolt at the joint 
  of the tank, we confirmed the leakage was stopped around 12:35 pm on 
  January 10. In addition, sandbags were piled around the water pond to 
  protect its expansion. Because water leaked from waste storage tank, it 
  does not need to stop the water treatment system and there was no impact 
  to the water injection to reactor.