*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.
 Water is currently injected at approx. 3.8 m3/h through reactor feed 
 water system piping arrangement. 
-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. 
-At 1:17 pm on October 26, we started cutting off the designated piping 
 after confirming that the hydrogen density inside the piping for cooling 
 in case of reactor shutdown was less than 0.1 %, as one of the 
 construction work to install gas monitoring system inside the Primary 
 Containment Vessel. At 3:15 pm on the same day, we finished cutting 
 pipes. After that, we conducted welding of blind plates of cut pipes and 
 covering holes of the pipes. At 7:00 pm on the same day, we finished all 
 operations. 

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. 2.9m3/h through reactor feed water 
 system piping arrangement, and at approx. 7.0 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.
-At 10:30 am on October 27, we conducted leak test of the system as a part 
 of construction to settle the gas control system of Primary Containment 
 Vessel at the reactor building of Unit 2. As a result, we confirmed 
 in-leak volume to the system had no problem. In addition, we conducted 
 tentative operation test. As a result, we confirmed operational aspect of 
 electric heater and exhaust fun had no problem. 

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. 2.9 m3/h through reactor feed 
 water system piping arrangement, and at approx. 8.0 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. (hydrazine injected from 1:30 pm to 3:08 pm) 

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 time, 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.
-At 10:00 am on October 20, we started transferring the accumulated water 
 from the basement of turbine building of Unit 3 to the High Temperature 
 Incinerator Building of Central Radioactive Waste Treatment Facility.
-At 10:12 am on October 20, we started transferring the accumulated water 
 from the basement of turbine building of Unit 2 to the Process Main 
 Building of Central Radioactive Waste Treatment Facility.
-From 5:31 pm on October 25 to 2:01 pm on October 26, we transferred the 
 accumulated water brought from the basement of turbine building of Unit 1 
 to the basement of turbine building of Unit 2. 
-From 10:00 am to 4:00 pm on October 26, we transferred the accumulated 
 water from the basement of turbine building of Unit 6 to the temporary 
 tanks. 
-On October 26, we replaced the hose for transferring reverse osmosis 
 membrane concentrated water in Water Desalinations (reverse osmosis 
 membrane) that liquid spoil was found on October 8,
-At 9:47 am on October 26, for the water injection to the reactors of 
 Units 1 to 3, we switched from normal water injection line to emergency 
 water injection line, due to the shutoff of facilities for power source 
 reinforcement work. After that, we switched from emergency water 
 injection line to normal water injection line due to completion of power 
 source reinforcement work. (At 4:10 pm on the same day, we confirmed flow 
 rate stability of Unit 1 and 2. At 3:33 pm on the same day, we confirmed 
 flow rate stability of Unit 3) Along with the switching work, we adjusted 
 the amount of water injection from water feeding system to approximately 
 3.8 m3/h for Unit 1's reactor. For Unit 2, we adjusted the amount of 
 water injection to the reactor to approximately 3 m3/h from water feeding 
 system and to approximately 7 m3/h from Core Spray System. Likewise, for 
 unit 3, we adjusted the amount of water injection to the reactor to 
 approximately 3 m3/h from water feeding system and to approximately 
 8 m3/h from Core Spray System.
-At 10:00 am on October 27, we started transferring accumulated water from 
 the temporary tank to the Mega Float. 
-At 9:55 am on October 27, we switched water injection line of unit 1 and 
 2 from normal water injection line to emergency water injection line to 
 add the vane to adjust flow amount of water injection line to the Unit 
 2's reactor in order to improve the ability to control the water 
 injection amount. At 2:35 pm on the same day, we switched from emergency 
 water injection line to normal water injection line due to completion of 
 the work. Injection amount is stable after the work.