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Corporate Information

 
Press Release (Jul 30,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 3:00 pm, July 30)
*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 11:57 am on July 30, the amount of water injection through feed water 
 system piping arrangement was adjusted to approx. 3.6 m3/h. 
 Water is currently injected at approx. 3.6 m3/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. 
-At 11:57 am on July 30, the amount of water injection through feed water 
 system piping arrangement was adjusted to approx. 3.6 m3/h. 
 Water is currently injected at approx. 3.6m3/h through 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. 8.9m3/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 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 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. (From 11:12 am to 12:57 pm on July 30, we also injected 
 hydrazine as corrosion inhibitor.) 
-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 10:00 am on July 30, we started transferring low level accumulated
 water from temporary tank to Mega Float.
-At 11:00 am on July 30, we transferred accumulated water at Unit 6 
 turbine building to the temporary tank. 
-At 11:04 am on July 30, we transferred accumulated water at spent fuel 
 common pool building to the water desalinations tank.  
-From 1:16 pm to 2:47 pm on July 30, fresh water was injected to the 
 reactor well and drier separator pit in Unit 4 to reduce the amount of 
 radiation dose in 5th floor of the reactor building. 
-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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