*Updates are underlined 

All 6 units of Fukushima Daiichi Nuclear Power Station have been shut downv. 

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. 4.8 m3/h from the reactor feed
  water system and approx. 1.9 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.
  Water is currently injected at approx.1.9m3/h through reactor feed water
  system piping arrangement and at approx. 8.2m3/h from piping of core
  spray system to the reactor.
- 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 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, we put the gas management system of the
  reactor containment vessel in operation.
- 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. 
  The current water injection volume is approx 2.9 m3/h from the reactor
  feed water system and approx. 6.1 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. 

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 9:13 am on January 4, 2012, we suspended the second cesium adsorption
  apparatus due to reverse cleaning of the filters because the amount of
  disposal water of the second cesium adsorption apparatus decreased
  generally since the start of operation on December 27, 2011. At 2:36 pm
  on the same day, we restarted to operate the second cesium adsorption
  apparatus and confirmed that the flow rate had steadied at 2:48 pm.
- 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.
- Since December 22, 2011, the atmospheric temperatures at point C of Unit
  1 Primary Containment Vessel (PCV) monitored by the Containment
  Atmospheric Monitoring System had risen (the atmospheric temperature of
  the PCV on December 22 was approx. 38°C, at 7 pm on December 27 was
  approx. 49°C). The other temperatures had not risen, so we conducted a
  survey checking the reliability of the meters from 9 am to 10 am on
  December 28, and we confirmed that there are no problems. From 11:00am
  to 12:15pm on the same day, we adjusted the volume of Nitrogen injection,
  from approx. 8 m3/h to approx.18 m3/h, and emission of the gas
  management system, from approx. 23 m3/h to approx.30 m3/h, in order to
  identify the cause by monitoring the system with the same injection and
  emission volume as before December 22. The temperature went up to
  approx. 54.6°C at 6:00 pm on December 28 at its maximum and fell to
  approx. 42.3°C at 11:00 am on January 4, 2012. Temperatures at other two
  points also indicated slight increases but are currently in the stable
  status.
   Point D: (Maximum) approx. 35.8°C at 5:00 pm on December 29, 2011 →
            approx. 32.1°C at 11:00 am on January 4, 2012. 
   Point E: (Maximum) approx. 40.0°C at 5:00 pm on December 29, 2011 →
            approx. 35.1°C at 11:00 am on January 4, 2012. 
  We will continuously conduct the survey for the cause of temperature
  increase and surveillance of the plant.
- At 10:01 am on January 3, 2012, we started to transfer accumulated water
  from the basement of turbine building of Unit 3 to the Centralized
  Radiation Waste Treatment Facility (Miscellaneous Solid Waste Volume
  Reduction Treatment Building [High Temperature Incinerator Building] and
  the Process Main Building).
- At 10:00 am on January 4, 2012, we started to transfer accumulated water
  from the basement of turbine building of Unit 6 to temporary tank.
- On January 3, 2012, we conducted dust sampling at the upper part of Unit 
  1 reactor building at emission filter of Unit 1 reactor building cover.