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Corporate Information

 
Press Release (Aug 05,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 3:00 pm, Aug 5)
 
*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. 3.9 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. 
 
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. 3.9 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.
  Water is currently injected at approx. 9.1 m3/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 11:00 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 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 7:09 am on August 4, we started transferring accumulated water at 
  Unit 2 turbine building to Centralized Radiation Waste Treatment Facility.
- At 8:42 am on August 5, we started transferring accumulated water at Unit 
  3 turbine building to Centralized Radiation Waste Treatment Facility.
- At 10:00 am on August 5, we started transferring water of low level 
  radioactive water from the outside temporary tank to the Mega-float.
- At 11:00 am on August 5, we started transferring accumulated water at 
  Unit 6 turbine building to the temporary tank. 
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