*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 7.8 ㎥/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. 2.8 ㎥/h through reactor feed 
 water system piping arrangement, and at approx. 7.3 ㎥/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. (From 1:29 pm to 3:14 pm on November 14, 
 hydrazine [corrosion inhibitor] was injected in conjunction with the 
 cyclic cooling.) 
-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. 2.7 ㎥/h through reactor feed 
 water system piping arrangement, and at approx. 8.1 ㎥/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. 
-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. 
 
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 10:00 am to 4:00 pm on November 13, we started to transfer the 
 accumulated water from Unit 6 turbine building to the temporary tank. 
-At 0:32 pm on November 14, an alarm went off at the measure (Continuous 
 Dust Monitor) installed in front of the main gate, which had continuously 
 measured the radioactivity concentration in air. The cause of the alarm 
 was assumed to be a defect of the equipment by clogged filters. Around 
 1:08 pm on the same day, the measure was reset and the monitoring was 
 resumed. The dust concentration near the main gate was measured 6 x 10-6 
 [Bq/㎤], which was less than the reference measure for wearing a full 
 face mask, 1 x 10-4 [Bq/㎤]. Although an instruction to wear a full face 
 mask since 0:39 pm was given responding the alarm, around 2:11 pm on the 
 same day it was announced that the workers did not have to wear a full 
 face mask as per normal.