* 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.
  The current water injection amount from the reactor feed water system is 
  approx.4.5 m3/h and that from the core spray system is approx. 1.9 m3/h.
- 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 
  feed water system, we started water injection from piping of core spray 
  system to the reactor. 
  Because the tendency of temperature rise at the bottom of PCV had been 
  accelerated since February 2, we increased the amount of water injected 
  to the reactor and continued monitoring the tendency of the temperature 
  fluctuation. Since the temperature had remained high around 70.0 °C, we 
  injected boric acid into the reactor as a safety countermeasures against 
  the re-criticality from 0:19 am to 3:20 am on February 7, and changed the 
  amount of the core spray system injection water from 3.7m3/h to 6.7m3/h 
  at 4:24 am (the amount of the continuing feed water system injection is 
  6.8m3/h). Currently, the temperature is approx. 68.5°C (as of 5 am on 
  February 11). We will monitor the progress continuously.
  6:20 pm on February 10, as decrease of water injection rate into reactor 
  of Unit 2 was observed, adjustment was made from approx.6.3m3/h to 
  approx. 6.8m3/h for feed water system and from approx. 6.6m3/h to approx. 
  6.7m3/h for core spraying system. 
  The current water injection amount from the reactor feed water system is 
  approx. 6.7m3/h and that from the core spray system is approx. 6.7m3/h.
- 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, a full-scale operation of the PCV gas 
  control system started. 
- At 10:46 am on December 1, 2011, we started the nitrogen injection to 
  the Reactor Pressure Vessel.
- At 11:50 am on January 19, 2012, we started the operation of the spent 
  fuel pool desalting facility. 

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 amount from the reactor feed water system is 
  approx. 2.9m3/h and that from the core spray system is approx. 6.1m3/h.
  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. 
  Since 9:50 am on February 10, we have conducted the work to add 
  flowmeters to the nitrogen injection line at the side of Primary 
  Containment Vessel of Unit 3 in order to improve the reliability of 
  nitrogen injection activity. During this period, due to this work, we 
  suspended the nitrogen injection task temporarily.
- At 4:26 pm on November 30, 2011, we started operation to inject nitrogen 
  into the reactor pressure vessel.
- At 3:18 pm on January 14, we started operation of the radioactive 
  material removal instrument for the spent fuel pool in Unit 3 

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. From 1:28 pm to 3:05 pm on February 10, we 
  started injection of hydrazine [corrosion inhibitor].
- 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 10:00 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 8:00 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.
- As accumulated water containing radioactive materials was found in the 
  trench between Process Main Building and Miscellaneous Solid Waste Volume 
  Reduction Treatment Building (High Temperature Incinerator Building) in 
  Centralized Radiation Waste Treatment Facility (December 18, 2011), 
  inspection of other trenches in the site was commenced from January 11.
  As a result of inspection on February 10, location where accumulated 
  water was found and results of nuclide analysis (preliminary result) are 
  shown below; 
  · Unit 6, inside of seawater pipe duct (SW system) 
    I-131:Below detection limit (ND), Cs-134:2.1x10-1Bq/cm3, 
    Cs-137:3.4x10-1Bq/cm3 
  · Unit 5, inside of seawater pipe duct (SW system) 
    I-131:ND, Cs-134:1.4x10-1Bq/cm3, Cs-137:1.5x10-1Bq/cm3 
  · No6, inside of trench for diesel fuel pipe 
    I-131:ND, Cs-134:2.5x10-1Bq/cm3, Cs-137:3.7x10-1Bq/cm3 
  · Unit 6, inside of pipe duct (b/w pump room and MG set build.) 
    I-131:ND, Cs-134:1.1x10-1Bq/cm3, Cs-137:2.0x10-1Bq/cm3 
  · Unit 6, inside of seawater pipe duct (North side, emergency line) 
    I-131:ND, Cs-134:ND, Cs-137:1.2x10-1Bq/cm3 
  · Unit 6, inside of seawater pipe duct (South side, emergency line) 
    I-131:ND, Cs-134:1.4x10-1Bq/cm3, Cs-137:2.0x10-1Bq/cm3 
- At 9:18 am on January 31, we started transfer of Sub-drain Water of Unit 
  6 to the temporary tank. We will conduct transferring to the temporary 
  tank appropriately. 
- At 2:43 pm on February 10, we started to transfer accumulated water from 
  underground floor of turbine building of Unit 2 to centralized radiation 
  waste treatment facility (Miscellaneous Solid Waste Volume Reduction 
  Treatment Building [High Temperature Incinerator Building]). 
- From 10:00 am to 4:00 pm on February 10, 2012, we transferred the 
  accumulated water from the turbine building of Unit 6 to the temporary 
  tank. 
- From 8:45 am to 4:39 pm on February 10, 2012, at the Centralized 
  Radiation Waste Treatment Facility, we transferred accumulated water from 
  On-site Bunker Building to Process Main Building.