*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.
-From 3:37 pm on March 25, we started injecting freshwater by a motor 
 driven pump which is now powered by the off-site transmission line.
 Water is currently injected at approx. 3.8m3/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. 

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. 
-From 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. 3.8 m3/h through reactor feed 
 water system piping arrangement, and at approx. 6 m3/h through core spray 
 system water injection piping arrangement.
-From 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. 

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.
-From 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.
-From 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. 2.6 m3/h through reactor feed 
 water system piping arrangement, and at approx. 8.1 m3/h through core 
 spray system water injection piping arrangement.
-From 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 3:00 pm on September 30, we stopped the 
 Fuel Pool Cooling and Filtering System in order to install an additional 
 transformer panel for the operation. At 7:26 pm, the power was restored 
 and the cooling by the equipment was resumed. 
-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.
-From 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. (From 1:57 pm to 3:48pm on September 27, we 
 also injected hydrazine [corrosion inhibitor].)
-From 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.
-From 9:45 am to 10:42 am on September 26, the B system (main) of sea 
 water pump on Residual Heat Removal System was switched to the A system 
 (temporary), in order to repair the outlet valve of the pump. Afterwards, 
 the repair was finished. From 11:21 am to 11:34 on September 30, the A 
 system (temporary) of sea water pump was switched to the B system (main).
-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 8:00 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 9:51 am on September 13, we started transferring accumulated water 
 from the turbine building of Unit 2 to High Temperature Incinerator 
 Building of Centralized Radiation Waste Treatment Facility. 
-At 10:00 am on September 30, we started transferring accumulated water 
 from the turbine building of Unit 6 to High Temperature Incinerator 
 Building of Centralized Radiation Waste Treatment Facility.
-At 10:00 am to 4:00 pm on September 30, we transferred the accumulated 
 water from the turbine building of Unit 6 to the temporary tank. 
-At 2:19 pm on September 30, the cesium adsorption instruments stopped 
 automatically due to the overload of transfer pump (A) for cesium 
 adsorption treated water. At 5:38 pm, transfer pump (B) was initiated and 
 the water treatment by the apparatus was resumed.