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Press Release (Aug 04,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 10:00 am, Aug 4)
*New items 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. 
 Water is currently injected at approx. 3.8 ㎥/h through reactor 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. 
 Water is currently injected at approx. 3.4 ㎥/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. 9.1 ㎥/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 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 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 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 0:44 am on July 31, we started cyclic cooking of Spent Fuel Pool of 
 Unit 4 by using alternative cooling system of the Pool's cooling and 
 filtering system. 
Others 
-At 11 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 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 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.
-From 4:13 pm on July 30 to 7:17 am on August 4, we transferred 
 accumulated water at Unit 3 turbine building to Centralized Radiation 
 Waste Treatment Facility.
-From 10 am to 5 pm on August 3, we transferred low level accumulated 
 water from temporary outside tank to mega-float.
-From 11 am to 4 pm on August 3, we transferred accumulated water from 
 Unit 6 Turbine Building to the temporary tank. 
-At 7:09 am on August 4, we started transferring accumulated water at 
 Unit 2 turbine building to Centralized Radiation Waste Treatment Facility. 
-At 5:32 am on August 4, we stopped Water Treatment Facility to improve 
 the flow rate. 
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