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Corporate Information

 
Press Release (Jul 13,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 10:00 am, July 13)
*Updates from previous press release 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. 3.4m3/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. 
  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. 9m3/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 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 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 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 3:15 pm on July 10, we started transferring the accumulated water from 
  the turbine building of Unit 3 to Centralized Radiation Waste Treatment 
  Facility Process Main Building.
- At 8:51 am on July 12, we found some leakage around the connection part 
  at the liquid chemical injection line of coagulation setting devices in 
  accumulated water treatment facilities and therefore stopped the 
  operation of the facilities. Afterward, we repaired the leakage part at 
  4:19 pm, started operation of the accumulated water treatment facilities 
  at 4:28 pm and resumed the accumulated water treatment at 4:58 pm. Also 
  water injection to the reactor has been carried on during this time. 
- From 11:00 am to 4:00 pm on July 12, we transferred low radioactive 
  accumulate water in the outside temporary tanks to the Mega Float.
- At 11:22 on July 12, in order to reduce radiation level on the 5th floor 
  of the reactor building of Unit 4, we started fresh water injection to 
  the reactor well and the pool to put equipment temporarily. However we 
  found water leakage from injection water line and stopped the injection 
  on 12:03 on the same day. As a result of survey, we found water leakage 
  from a connection part with water hose. Today we will restart the water 
  injection after changing the hose.
- As a countermeasure against seawater leakage from the piping of the 
  outside temporary residual heat removal seawater system of the residual 
  heat removal system of the Unit 5 occurred on July 3, we bound the piping 
  tightly. However we found the similar part after reconfirmation of the 
  site, in terms of preventive maintenance, we stopped the residual heat 
  removal system at 6:30 am on July 13, stopped outside temporary seawater 
  cooling pump at 6:44 am, and then started the piping replacement. 
- At 10:00 am on July 13, we started transferring low radioactive 
  accumulate water in the outside temporary tanks to the Mega Float. 
- 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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