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Corporate Information

 
Press Release (Jul 21,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 3:00 pm, July 21)
*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. 3.7m3/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. From 2:25pm on July 17, the motor driven pump 
  of Unit 2 is injecting the freshwater to the Unit 1 and 2 reactors.
  Water is currently injected at approx. 3.8m3/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. 9.0m3/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. 
Injury accident 
- Around 10:06 am on July 18, a worker of the partner company fell from 
  the distribution pole during the connection work of the optical cable 
  near the observatory entrance of the station. He was transported to the 
  Iwaki Kyouritsu Hospital by the helicopter emergency medical service 
  (called "Doctor Heli"). 
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 10:50 am on July 16, we started transfer of the accumulated water from 
  the Turbine Building of Unit 3 to the Process Main Building of the 
  Centralized Radiation Waste Treatment Facility.
- At 10:56 am on July 16, we started transfer of the accumulated water from 
  the Turbine Building of Unit 2 to the Process Main Building of the 
  Centralized Radiation Waste Treatment Facility.
- From 8:30 am on July 18, we started an installation work of a temporary 
  roof for the Unit 3 turbine building in order to cover the roof's opening 
  as a measure for rainwater.
- On July 21, in order to conduct a restoration work for double circuit of 
  Yonomori line which is power source for Unit 5 and Unit 6, we started 
  a power switching work to stop the operation of Okuma Line No.3 which 
  was connected to Yonomori Line No.1. According to this work, we stopped 
  the alternative cooling system for the fuel pool cooling and filtering 
  system of Unit 3 at 8:02 am, the water treatment system at 8:38 am, and 
  the cooling system for the common pool at 8:40 am. After that, upon 
  starting of power receiving from Okuma Line No.2, we started the cooling 
  system for the common pool at 2:41 pm, and the alternative cooling system 
  for the fuel pool cooling and filtering system of Unit 3 at 2:52 pm. 
- At 11:00 am on July 21, we started transferring accumulated water from 
  the Turbine Building of Unit 6 to temporary tanks. 
- 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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