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Corporate Information

 
Press Release (Aug 11,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 3:00 pm, Aug 11)
 
*New items 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. 3.9 m3/h through reactor feed 
  water system piping arrangement.
- We commenced injection of nitrogen gas into Primary Containment Vessel 
  at 1:31am on April 7.
- At 9:00 am on August 10, we started to assemble steel frame for the 
  Reactor Building Cover. 
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. 3.9 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. However at 4:22 pm on August 10, we 
  adjusted the flow rate of injection water to the reactor.
  Water is currently injected at approx. 9.1 m3/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 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 don't think there is any reactor coolant leakage 
  inside the primary containment vessel. 
Unit 5 (Outage due to regular inspection) 
- Sufficient level of reactor coolant to ensure safety is maintained.
- At 5 am on March 19, we started the Residual Heat Removal System Pump 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 time, we don't think there is any reactor coolant leakage inside 
  the primary containment vessel. 
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 of Unit 6 to cool down Spent Fuel Pool.
- At 7:27 pm on March 20, the reactor achieved cold shutdown. 
- At this time, we don't think there is any reactor coolant leakage inside 
  the primary containment vessel.
- From 9:30 am to 1:40 pm on August 9, we conducted plumbing between 
  temporary pump and residual heat removal system pump (A) to enforce the 
  connection method. We stopped the power source of residual heat removal 
  system pump (B) during this work. Even though cooling of a reactor and a 
  spent fuel pool were temporarily suspended, there are no safety issues 
  regarding this. 
Operation for cooling the Spent Fuel Pools 
- At 5:21 pm on May 31, we started cyclic cooling of Spent Fuel Pool of 
  Unit 2 by using alternative cooling system of the Pool's cooling and 
  filtering system.
- At 7:47 pm on June 30, we started cyclic cooling of Spent Fuel Pool of 
  Unit 3 by using alternative cooling system of the Pool's cooling and 
  filtering system.
- At 0:44 am on July 31, we started cyclic cooling of Spent Fuel Pool of 
  Unit 4 by using alternative cooling system of the Pool's cooling and 
  filtering system.
- At 11:22 am on Aug 10, we started cyclic cooling of Spent Fuel Pool of 
  Unit 1 by using alternative cooling system of the Pool's cooling and 
  filtering system. 
Injured 
- Around 12:05 pm on August 10, one partner company worker who was mowing 
  for curing of water treatment hose at west side of Centralized Radiation 
  Waste Treatment Facility (outside) was injured his right leg by sickle 
  and was transferred to the Fukushima Rosai Hospital by the ambulance. 
  Diagnose was given as contusion of right leg. 
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 around 10 am on June 13, we started the operation of the circulating 
  seawater purification facility installed at the screen area of Unit 2 
  and 3.
- At 8:00 pm on June 17, we started operation of Water Treatment Facility 
  against the accumulated water. 
- 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 8:42 am on August 5, we started transferring accumulated water at 
  Unit 3 turbine building to Centralized Radiation Waste Treatment 
  Facility.
- At 10:00 am on August 9, we started transferring low level accumulated 
  water from outdoor temporary tanks to Mega Float. However, at 10:12 am, 
  since leakage was confirmed from the transferring pipes cabled at 
  outside, we stopped transferring. Thereafter, such pipes were replaced 
  and at 1:35 pm, we resumed transferring.
- At 11:00 am on August 9, we started transferring of accumulated water 
  from inside the Unit 6 turbine building to temporary tanks and finished 
  on 5:00 pm on August 10.
- At 4:47 pm on August 10, we started transferring of accumulated water 
  from turbine building of unit 2 to Centralized Radiation Waste Treatment 
  Facility.
- At 10:00 am on August 11, we started transferring of accumulated water 
  from inside the Unit 6 turbine building to temporary tanks.
- At 11:20 am on August 11, as we found a little water leakage (about one 
  drop of water per 20 seconds) in the primary hose of the circulating 
  cooling equipment for the spent fuel pool in the centralized radiation 
  waste treatment facility of Unit 4, we covered and reinforced the 
  leakage part with plastic. We are planning to replace the hose, etc. We 
  have continued circulating cooling of the spent fuel pool. 
- At 12: 25 pm on August 11, water treatment facility stopped due to the 
  malfunction of the water level indicator of the decontamination 
  instrument tank, but we replaced the broken one with another and 
  activated it at 12:40 pm, and then at 12:58 pm resumed treating the 
  accumulated water. 
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