*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.
 As we confirmed a change in water injection amount into the reactor at 
 7:20 pm on February 3, we adjusted water injection amount through feed 
 water system from approx. 4.7 m3/h to approx. 4.5 m3/h. 
 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. 2 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. 
 To improve reliability of water injection to the reactors, the injection
 line connecting to the reactor injection pump on the hill was replaced
 with polyethylene pipes and we have been changing the route for reactor 
 injection from feed water system to reactor core spray system in a 
 stepwise manner. After completion of adjusting water flow amount as 
 planned on February 2, tendency of temperature rise at the bottom of PCV 
 was observed. Thus, at 7:20 pm on February 3, we changed the injection 
 amount into Unit 2 reactor through feed water system from approx. 2.9 m3/h 
 to approx. 4.9 m3/h and changed that though reactor core spray system 
 from approx. 5.8 m3/h to approx. 3.8 m3/h (which means setting them at 
 those of before flow adjustment on February 1). As for the temperature 
 rise, the temperature at the upper head of the bottom of PCV has risen to 
 approx. 66.8 °C at the highest (as of 7 am on February 4), but currently, 
 it is approx. 64.8°C (as of 11 am on February 4). The trend of the 
 temperature rise seems to be steady and we will monitor it continuously. 
 The current water injection amount from the reactor feed water system is
 approx. 4.8 m3/h and that from the core spray system is approx. 3.8 m3/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
 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. 
 As we confirmed a change in water injection amount into the reactor at 
 7:20 pm on February 3, we adjusted water injection amount through core 
 spray system from approx. 5.5 m3/h to approx. 6 m3/h. 
 The current water injection amount from the reactor feed water system is
 approx. 3m3/h and that from the core spray system is approx. 6m3/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. (From 1:24 pm to 3:07 pm on February 3,
 2012, we injected hydrazine [corrosion inhibitor].)
-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.
-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.
-At 4:07 pm on February 3, 2012, we started to transfer accumulated water 
 from the basement of T/B, Unit 2 to the Centralized Waste Treatment 
 Facility (Miscellaneous Solid Waste Volume Reduction Treatment Building 
 [High Temperature Incinerator Building] and Process Main Building).  
-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.
-From 10 am to 4 pm on February 3, 2012, we transferred the accumulated
 water from within Unit 6 T/B to the temporary tanks.