*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. 3.5 m3/h through reactor feed 
 water system piping arrangement. 
-We commenced injection of nitrogen gas into Primary Containment Vessel at 
 1:31am on April 7. 
-At 9:00 am on August 10, we started to assemble steel frame for the 
 Reactor Building Cover. 
 
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 4:27 pm on September 6, as it was confirmed that there was a decrease 
 in the amount of water injection for the reactor, we adjusted the rate of 
 water injection through reactor feed water system piping arrangement to 
 approx. 3.8 m3/h. 
 Water is currently injected at approx. 3.6 m3/h through reactor feed 
 water system piping arrangement. 
-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 11:01am 
 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 2:09pm to 2:58pm on September 1, we adjusted the water flow into the 
 reactor and started water injection by core spray system in addition to 
 water injection by the reactor feed water system piping arrangement. 
 At 2:43 pm on September 5, we adjusted the rate of water injection 
 through reactor feed water system piping arrangement to approx. 6 m3/h. 
 Water is currently injected at approx. 6 m3/h through reactor feed water 
 system piping arrangement, and at approx. 3 m3/h through core spray 
 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 approximately 6 am on March 15, we confirmed the explosive sound and 
 the sustained damage around the 5th floor rooftop area of Reactor 
 Building. 
-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 this time, we don't think there is any reactor coolant leakage inside 
 the primary containment vessel. 
 
Operation for cooling the Spent Fuel Pools 
-At 5:21 pm on May 31, we started cyclic cooling of Spent Fuel Pool of 
 Unit 2 by using alternative cooling system of the Pool's cooling and 
 filtering system. 
-At 7:47 pm on June 30, we started cyclic cooling of Spent Fuel Pool of 
 Unit 3 by using alternative cooling system of the Pool's cooling and 
 filtering system. 
-At 12:44 pm on July 31, we started cyclic cooling of Spent Fuel Pool of 
 Unit 4 by using alternative cooling system of the Pool's cooling and 
 filtering system. 
-At 11:22 am on Aug 10, we started cyclic cooling of Spent Fuel Pool of 
 Unit 1 by using alternative cooling system of the Pool's cooling and 
 filtering system. 
 
Others 
-At around 10 am on June 13, we started the operation of the circulating 
 seawater purification facility installed at the screen area of Units 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 2nd 
 cesium adsorption instrument. 
-At 11:34 am on August 20, we started operation of the desalting facility 
 for the spent fuel pool of Unit 4 
-At 9:39 am on August 30, we started transferring accumulated water from 
 the turbine building of Unit 2 to Process Building of Centralized 
 Radiation Waste Treatment Facility. 
-At 9:54 am on August 30, we started transferring accumulated water from 
 the turbine building of Unit 3 to High Temperature Incinerator Building 
 of Centralized Radiation Waste Treatment Facility. 
-At 5:51 am on September 6, the decontamination instruments of Waste 
 Treatment Facility stopped with an alarm indicating a mixer trouble* of 
 High Speed Coagulation Settling Facility. We reset and restarted the 
 instruments. However, the same alarm and serious fault alarm went off at 
 6:21 am, and the decontamination instruments and cesium adsorption 
 instruments stopped. Through some investigation, as it was confirmed that  
 the electricity set value of overload trip of decontamination instruments  
 was nearly the same level of that for normal operation, we adjusted the  
 value and at 3:13 pm on the same day we restarted the water treatment  
 facility, and at 4:35 pm the rate reached the rated value.  
-From 10:00 am on September 7, we transferred accumulated water in turbine  
 building of Unit 2 from the condenser to the basement.