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Corporate Information

 
Press Release (Jun 29,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 3:00 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.
- Since the amount of water injected into the reactor was decreased at 
  1:49 pm on June 29, we adjust water injection at approx. 3.5 m3/h 
  through reactor feed water system piping arrangement. Water is currently 
  injected at approx. 3.5 m3/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. 3.5 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 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.
- At 2:45 pm on June 29, we started injecting water into Unit 3 using a 
  temporary motor driven pump. 
- 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. At 10:59 am, we replaced the pipe with 
  a new one while operation of the processing transfer pump was suspended. 
  We started to operate circulating injection cooling at 1:33 pm. 
- At around 9:30 am on June 29, water leakage was confirmed at the drain 
  of lower part of the primary storage tank for water desalinations 
  reverse osmosis membrane concentrated water in the accumulated water 
  treatment system. We stopped the leakage by installing a drain cap at 
  10:30 am. 
- Since an alarm showing water leakage was sounded in the On-site Bunker 
  Building at 2:49 pm, the accumulated water treatment system was stopped 
  at 2:53 pm. 
- 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.
- At around 11:45 am on June 29, while going to the accumulated water 
  treatment system for inspection, a worker of a partner company was out 
  of the Main Anti-Earthquake Building, wearing his mask without a filter 
  for one minute. He returned to the Main Anti-Earthquake Building 
  immediately after he noticed it. The result of Whole Body Counter 
  examination suggests that the level of internal radioactivity was 
  extremely low enough not to affect his body. 
- 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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