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Corporate Information

 
Press Release (Jun 29,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 10:00 pm, June 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. 3.5m3/h through reactor feed water 
  system piping arrangement.
- We commenced injection of nitrogen gas into Primary Containment Vessel at
  1:31am 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 freshwater by a motor driven pump powered by the 
  off-site transmission line. 
  At 6:27 pm on June 23, we changed the water injection line so that we can
  inject water to Unit 1 and 2 by the motor driven pump for Unit 1 and 
  stopped the motor driven pump for Unit 2. 
  Water is currently injected at approx. 3.5m3/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 m3/h through reactor feed water 
  system piping arrangement.

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 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. 
- We will continuously conduct further water spray depending on the 
  conditions of spent fuel pools, if needed.

Others
- At 1:30 pm on April 26, we started spraying the dust inhibitor inside the
  site. 
- 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 June17, we started operation of water treatment of 
  accumulated water at accumulated water treatment facility. 
- At 9:56 am on June 22, we started transferring accumulated water in 
  turbine building of Unit 2 to central waste treatment facility building.
- At 4:20 pm on June 27, the operation of circulation injection cooling was
  initiated by injecting water from the filter water tank as well as usage 
  of the treated water regarding water injection to the reactor. At 5:55 
  pm, since we confirmed a leakage from the pipe which supplies water from 
  treated water tank to injection pump of reactor, we stopped supplying 
  treated water. Subsequently, we have implemented measures against the 
  leakage at pipe joint. At 2:36 pm on June 28, we started operation of 
  supply pump for treated water, and resumed the operation of circulation
  injection cooling at 3:55 pm.
- At around 3:00 pm on June 28, water blot was confirmed at the outlet
  flange of the processing transfer pump of the accumulated water treatment
  system, and a saucer was installed at 3:45 pm. After that, no increase
  of the blot has been confirmed.
- At 8:10 am on June 29, (two) minute holes were confirmed at the hose for
  the injection cooling system of the accumulated water treatment system,
  and we temporally repaired them. We will replace the hose as soon as the
  supply is ready.
- From 9:40 am to 3:29 pm on June 28, we injected fresh water to the 
  reactor well (unit 4) and temporally dry separation pool for environment 
  improvement (reduce radio active dose) on 5th floor reactor building of 
  unit 4. 
- At 12:00 pm on June 28, we found the water level gauge (manometer) of 
  temporary tank where accumulated water from turbine building in Unit 6 
  will be transferred lying on the floor. Since accumulated water was 
  leaking from the gauge, we stopped it by closing main valve. For safety, 
  we measured surface dose rate around and confirmed the result to be 
  equivalent to that of surrounding area.
- 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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