*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 volume is approx. 4.5 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.
  We are gradually adjusting the water injection rate to Reactor, Unit 2 
  in order to switch the water injection piping for reactor injection pump 
  on the hill. At 9:55 am on January 21, we adjusted the amount of the 
  water injection from approx. 5.0 m3/h to approx. 6.0 m3/h through the 
  reactor feed water system, from approx. 5.0 m3/h to approx. 4.0 m3/h 
  through the core spray system. 
  The Current water injection volume is approx. 6.0 m3/h from the reactor
  feed water system and approx. 4.0 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 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.
- 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 volume is approx 5.0 m3/h from the reactor
  feed water system and approx. 3.9 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.
- 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 1:30 pm to 3:14 pm on January 12,
  2012, we injected hydrazine [corrosion inhibitor] in conjunction with
  the cyclic cooling).
- 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 finding of accumulated water containing radioactive materials at the
  trench between the Process Main Building and the Miscellaneous Solid
  Waste Volume Reduction Treatment Building [High Temperature Incinerator
  Building] (December 18, 2011), we started the inspection of other
  trenches at the site on January 11. 
  As a result of the inspection on January 20, the places where
  accumulated water was confirmed and the nuclide analysis results
  (preliminary results) are as follows:
  Off-gas piping duct, Unit 3 
  I-131: below detection limit, Cs-134: 3.1x101Bq/cm3, 
  Cs-137:4.1x101Bq/cm3 
- At 9:42 on January 19, we started injecting water to unit 3 condensate
  storage tank. At 6:00 pm on the same day, we finished filling water. At 
  9:05 am on January 21, we restarted filling water. 
- From 10:00 am to 4:00 pm on January 20, we transferred accumulated water
  from the basement, T/B, Unit 6 to temporary tanks.
- At 3:37 pm on January 20, we started transferring accumulated water from 
  the basement, T/B, Unit 1 to the basement, T/B, Unit 2. 
- At 3:23 pm on January 20, we started transferring accumulated water from 
  the basement of T/B, Unit 2 to the Central Radioactive Waste Treatment 
  Facility (Miscellaneous Solid Waste Volume Reduction Treatment Building 
  [High Temperature Incinerator Building]). 
  At 7:02 am on January 21, a worker from the cooperating company found 
  water leakage from the transfer piping at the large equipment hatch, T/B, 
  Unit 4. 
  We checked the work site and observed water leakage from a flange of the 
  piping to a valve unit. Part of water dripped to the floor outside of 
  the valve unit. At 7:48 am on the same date, we stopped the transfer 
  pump for the accumulated water. At 7:55 am, we confirmed that the 
  dripping of water stopped. The water was within the T/B and there was no 
  leakage to outdoor, no leakage to the sea. The volume of water dripped 
  to the floor of T/B was approx 2 liters. The surface dose rate was 
  0.1mSv/h. We will conduct flushing of the transfer piping for 
  accumulated water, check the flange and repair. 
- At 3:17 pm on January 20, we started transferring accumulated water from 
  the basement of T/B, Unit 3 to the Central Radioactive Waste Treatment 
  Facility (Miscellaneous Solid Waste Volume Reduction Treatment Building 
  [High Temperature Incinerator Building]).