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Corporate Information

 
Press Release (Aug 24,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 3:00 pm, Aug. 24)
*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. 3.7 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. 3.8 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. 7 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 (System 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. 
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. (From 10:35 am to 0:29 pm on Aug 24, we injected 
  hydrazine (corrosion inhibitor) as well.) 
- 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 12:44 pm 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. 
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 Units 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 7:41 pm on August 19, we started treatment of accumulated water by 
  parallel operation of one line from the cesium adsorption instrument to 
  the decontamination instrument and the other treatment line of the 2nd 
  cesium adsorption instrument. 
- At approximately 4:00 pm August 23, we confirmed that Water Desalination 
  1B (Type of Reverse Osmosis Membrane) had stopped. We adjusted a water 
  flow rate control device and at 6:20 pm on the same day, we restarted the 
  facility.
- At 4:19 pm on August 18, we transferred accumulated water from the 
  turbine building of Unit 2 to Central Radioactive Waste Treatment 
  Facility.
- At 11:34 am on August 20, we started operation of the desalting facility 
  for the spent fuel pool of Unit 4
- At 9:39 am on August 21, we started transfer of accumulated water from 
  the turbine building of Unit 3 to Miscellaneous Solid Waste Volume 
  Reduction Treatment Building (High Temperature Incinerator Building), but 
  temporarily suspended the transfer and confirmed the system structure. On 
  August 23, we started two transfer pumps and started transferring to 
  Solid Waste Volume Reduction Treatment Building (High Temperature 
  Incinerator Building) and Process Main Building in Centralized Radiation 
  Waste Treatment Facility.
  Then at 9:30 am on August 24, we stopped transferring to Solid Waste 
  Volume Reduction Treatment Building (High Temperature Incinerator 
  Building) and changed the transfer to Process Main Building in 
  Centralized Radiation Waste Treatment Facility by two transfer pumps. 
- At 10:00 am on August 23, we started transfer of accumulated water from 
  the turbine building of Unit 6 to temporary tanks. 
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