*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 ㎥/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 ㎥/h through reactor feed 
 water system piping arrangement, and at approx. 7.2 ㎥/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.
-On November 22, we sampled gases in gas management system in primary 
 containment vessel of Unit 2 to analyze nuclides. As a result of nuclides 
 analysis, we evaluated that there is no recriticality since the density 
 of Xe-135 is below the detection limits (1.1 x 10-1 Bq/cm3) and that 
 indicates the analyzed figure is below the determination criteria for 
 recriticality such as 1 Bq/㎤. Regarding Xe-135, we decided to use the 
 sampling result at gas vial container at inlet in gas management system 
 to evaluate the recriticality based on the "Report with regard to "Policy 
 on the mid term security" for the Units 1 to 4 of Fukushima Daiichi 
 Nuclear Power Station to Nuclear and Industrial Safety Agency at the 
 Ministry of Economy, Trade and Industry (1) (revision)" (Press released 
 on November 9th) because charcoal filter was used to detect Xe-135 and we 
 evaluated that they are created by spontaneous fission. 
 * Detection Limits Charcoal Filter: Order of 10-6, Gas Vial Container: 
   Order of 10-1 
-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. 2.2 ㎥/h through reactor feed 
 water system piping arrangement, and at approx. 8.2 ㎥/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.
-On November 23, we finished all of this clean up work. At around 5:00 pm 
 on the same day, when we restarted pump of auxiliary cooling sea water 
 system (A) which was stopped due to the work, it was shut down 
 automatically right after it was restarted. Currently the cause is under 
 investigation. Reactor water and Spent Fuel Pool are planned to be cooled 
 alternatively by pump of residual heat removal system (A) until the pump 
 is recovered. The rise of increase in temperature of reactor water is 
 about 1.2°C/h and spent fuel pool is about 0.3°C/h and we think there are 
 no problems on these values.
 
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.
-As organized the preparation work of change of the hose for condensed 
 water transferring line and desalination transferring line with the water 
 desalinations (reverse osmosis membrane type) which water leak was found on 
 November 17, we had changed the hose from November 22 to 23. 
-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 to 9:45 am on November 24, we had transferred the 
 stored water from the condensate storage tank to basement of turbine 
 building of Unit 3
-At 9:31 am on November 24, we started transferring water from On-site 
 Bunker Building to Centralized Radiation Waste Treatment Facility Process 
 Building.