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Corporate Information

 
Press Release (Jul 29,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 10:00 am, July 29)
*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. 
  Water is currently injected at approx. 3.7 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. 
  Water is currently injected at approx. 3.5m3/h through feed water system 
  piping arrangement.
- At 5:30 pm on July 28, flow rate of injecting water to Unit 2 reactor 
  through feed water system was adjusted to approx. 3.6m3/h after reduction 
  of flow rate was observed. 
  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. 9.0m3/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.
- From 4:53 pm on July 22 to 9:48 am on July 29, we implemented 
  transferring accumulated water at Unit 3 turbine building vertical shaft 
  to the Centralized Radiation Waste Treatment Facility (Process Main 
  Building).
- From 4:56 pm on July 22 to 9:43 am on July 29, we implemented 
  transferring accumulated water at Unit 2 turbine building vertical shaft 
  to the Centralized Radiation Waste Treatment Facility (Process Main 
  Building).
- At 10:00am on July 27, we started to transfer low level accumulated water 
  from the outdoor temporary tank to the "Mega-Float." However, it was 
  stopped at 10:45am due to leakage from the transfer pump. The replacement 
  work was started from 0:30pm and ended at 2:00pm. We implemented the 
  transfer from 10 am to 5 pm on July 28. 
- From 11am to 4 pm on July 28, we transferred accumulated water at Unit 6 
  turbine building to the temporary tank. We resuimed the transfer from 10 
  am on July 29.
- From 2:33 pm to 6:50 pm on July 28, we implemented fresh water injection 
  into the Reactor well and the Drier separator pit of Unit 4, in order to 
  lower the radiation level at 5th floor of the Unit 4 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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