*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. It was assumed to be hydrogen explosion.
-At 3:37 pm on March 25, 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.
 The current water injection volume is approx 5.6 m3/h from the reactor
 feed water system.
-We commenced injection of nitrogen gas into Primary Containment Vessel at
 1:31 am on April 7.
-At 11:22 am on August 10, 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, we completed installation of the cover for the Reactor
 Building in order to contain dispersion of radioactive substances.
 
Unit 2 (Shut down) 
-At approximately 6:00 am on March 15, an abnormal noise began emanating
 from nearby Pressure Suppression Chamber and the pressure within the
 chamber decreased. 
-At 10:10 am on March 26, 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, we started injecting water to the reactor
 through core spray system water injection piping arrangement in addition
 to the water injection through reactor feed water system piping
 arrangement.
 Water is currently injected at approx. 2.9 m3/h through reactor feed
 water system piping arrangement, and at approx. 7.1 m3/h through core
 spray system water injection piping arrangement.
-At 5:21 pm on May 31, 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, we started injecting nitrogen gas into the Primary
 Containment Vessel.
-From 6:00 pm on October 28, we put the gas management system of the
 reactor containment vessel in operation.
-At 11:04 am on November 6, we started operation of radioactive material
 decontamination instrument of spent fuel pool.
 
Unit 3 (Shut down) 
-Explosive sound and white smoke were confirmed at approximately 11:01 am
 on March 14. It was assumed to be hydrogen explosion.
-At 6:02 pm on March 25, 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, we started water injection by core spray
 system in addition to water injection by the reactor feed water system
 piping arrangement. 
 Water is currently injected at approx. 2.3 m3/h through reactor feed
 water system piping arrangement, and at approx. 8.2 m3/h through core
 spray system water injection piping arrangement.
-At 7:47 pm on June 30, 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, injection of nitrogen gas into the Primary
 Containment Vessel started.
 
Unit 4 (Outage due to regular inspection) 
-At around 6 am on March 15, 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, 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. (Hydrazine was also injected from 1:15 pm
 to 2:50 pm on November 17)
-At 11:34 am on August 20, we started an operation of desalination
 equipment in the spent fuel pool.
-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, we started the Residual Heat Removal System Pump
 in order to cool the spent fuel pool.
-At 2:30 pm on March 20, the reactor achieved cold shutdown.
-At 2:45 pm on July 15, we started the operation of the original Residual
 Heat Removal System (System B) by its original seawater pump.
-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, we started the Residual Heat Removal System Pump
 of Unit 6 to cool down Spent Fuel Pool.
-At 7:27 pm on March 20, the reactor achieved cold shutdown. 
-At 2:33 pm on September 15, 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 time, we don't think there is any reactor coolant leakage inside
 the primary containment vessel. 
-From November 15, we started to cleanup work in order to prevent
 performance deterioration of pump caused by inletting sand or other
 materials piled up at the bottom of pump room of intake channel.
 
Others 
-At around 10 am on June 13, 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, 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, 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, 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, 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 9:10 am on November 10, we started transfer of accumulated water from
 the basement of Unit 2 turbine building to Centralized Radiation Waste
 Treatment Facility High Temperature Incinerator Building.
-At 9:25 am on November 15, we started transfer of accumulated water from
 basement of Unit 3 turbine building to Centralized Radiation Waste
 Treatment Facility Building.
-Regarding the oil cooler of (in-vehicle) transformer B system of Okuma
 line power system 3, from which we observed a leakage on October 3,
 materials and equipments have been prepared to start exchanging the oil
 cooler of the transformer from November 22. In order to change the power
 source of the loads which receive power from Okuma line 3 to Okuma line
 2, we stopped operation of water treatment facilities (cesium adsorption
 apparatus, second cesium adsorption apparatus, water desalinations
 (reverse osmosis membrane), and evaporative concentration apparatus) one
 by one from 5:00 am on the same day. There will be no influence on water
 injection into the reactor, because it will be continued using the
 desalinated water stored in the tank. At 2:06pm, we completed switching
 the power source to Okuma line 2. Afterwards, we restarted related
 facilities sequentially, and all facilities which had been stopped were
 resumed at 11:50 pm on the same day
-From 10:00 am to 4:00 pm on November 21, we transferred accumulated water
 from the turbine building of Unit 6 to the temporary tank.
-As part of improving the liability of water injection into the reactors,
 we plan to build reactor water injection facilities at Units 1 to 3. From
 10:22 am on November 21, we started transferring the stored water from
 the condensate storage tank to basement of turbine building of Unit 3
-Regarding the water leakage from pressure hose connecting point of
 absorption side of emergency feed water injection pump located upland of
 Unit 1 on November 18, we started to change these hoses at 9:30 am on
 November 22 and finished the work at 10:20 am on the same day because we
 were ready for the exchange these hoses, there is no effect caused by the
 installation work because we continue water injection into the reactor
 with the regular-use feed water pump located upland.