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Press Release (Sep 01,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 3:00 pm, Sep. 1)
 
*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.
- 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. 3.6m3/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. 3.7 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.
- From 2:09pm to 2:58pm on September 1, we controlled the water flow into 
  the reactor and started water injection by core spray system in addition 
  to water injection by the 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 5:00 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 (System B) by its original seawater pump.
- 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.
- 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. (From 11am to 1pm on September 1, hydrazine [corrosion 
  inhibitor] is injected.) 
- 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 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 30, we started transferring accumulated water from
  the turbine building of Unit 2 to Process Building of Centralized
  Radiation Waste Treatment Facility.
- At 9:54 am on August 30, we started transferring accumulated water from
  the turbine building of Unit 3 to High Temperature Incinerator Building
  of Centralized Radiation Waste Treatment Facility.
- At 10:00 am on September 1, we started transferring accumulated water
  from the turbine building of Unit 6 to a temporary tank. 
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