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Corporate Information

 
Press Release (Jul 24,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 3:00 pm, July 24)
*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 approximately 2:30 am on March 23, seawater injection to the reactor 
 through the reactor feed water system was initiated.
-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. 
-At 11:10 am on July 24 we confirmed some decrease of injection amount of 
 water into the reactor and therefore we have changed the amount and have 
 been injecting water at approx. 3.8㎥/h. 
 Water is currently injected at approx. 3.5㎥/h through feed water system 
 piping arrangement.
-We commenced injection of nitrogen gas into Primary Containment Vessel 
 at 1:31am on April 7. 
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. From 2:25pm on July 17, the motor driven pump 
 of Unit 2 is injecting the freshwater to the Unit 1 and 2 reactors.
-At 9:35 am on July 23, since the volume of injected water into the 
 reactor was found to be decreased, we adjusted the volume up to 3.8㎥/h. 
 Hence, water is currently injected at approx. 3.8㎥/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.
 Water is currently injected at approx. 9.0㎥/h through reactor feed water 
 system piping arrangement.
-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 6:00 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 do not consider any reactor coolant leakage inside the 
 primary containment vessel has occurred. 
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 
 (C) 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 Pump (B).
-At this moment, we do not consider any reactor coolant leakage inside the 
 primary containment vessel has occurred. 
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 
 (B) of Unit 6 in order to cool the spent fuel pool.
-At 7:27 pm on March 20, the reactor achieved cold shutdown. 
-At this moment, we do not consider any reactor coolant leakage inside the 
 primary containment vessel has occurred. 
Operation for cooling the spent fuel pools 
-At 5:21 pm on May 31, we started cyclic cooling of the spent fuel pool in 
 Unit 2 using alternative cooling system for fuel pool cooling and 
 filtering system. 
-At 7:47 pm on June 30, we started cyclic cooling of the spent fuel pool 
 in Unit 3 using alternative cooling system for fuel pool cooling and 
 filtering system.
-We will continuously conduct further water spray depending on the 
 conditions of spent fuel pools, if needed. 
Others 
-At 11:00 am on May 10, we started transferring accumulated water from the 
 underground level of reactor building to the radiation waste treatment 
 facility of Unit 6.
-At approximately 10:00 am on June 13, we started the operation of the 
 circulating seawater purification facility installed at the screen area 
 of Unit 2 and 3.
-From 8:00 pm on June 17, we started operation of water treatment of 
 accumulated water at accumulated water treatment facility. 
-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 4:53 pm on July 22, we started transferring accumulated water at Unit 
 3 turbine building vertical shaft to the Centralized Radiation Waste 
 Treatment Facility (Process Main Building).
-At 4:56 pm on July 22, we started transferring accumulated water at Unit 
 2 turbine building vertical shaft to the Centralized Radiation Waste 
 Treatment Facility (Process Main Building).
-From 11 am to 6 pm on July 23, we transferred accumulated water from the 
 turbine building of Unit 6 to the temporary tank.
-Water treatment facility, which was stopped for the work to restore 
 double circuit of Yonomori line which is power source for Unit 5 and Unit 
 6, started its operation at 3:26 pm on July 23, and the treatment of 
 accumulated water was resumed at 4:27 pm.
-At 10:37 am on July 24, in order to decrease the radiation dose in the 
 5th floor in the reactor building of Unit 4, we started to inject fresh 
 water into the reactor well and the drier separator pit of the Unit. 
-At 11:00 am on July 24, we started to transfer accumulated water from 
 the turbine building of Unit 6 to the temporary tank. 
-We will continue to take all measures to ensure the safety and to 
 continue monitoring the surrounding environment around the power station. 
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