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Corporate Information

 
Press Release (Jun 19,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 3:00 pm, June 19)
*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 powered by the off-site transmission line. We are now 
  injecting freshwater by a motor driven pump powered by the off-site 
  transmission line. Current injected water amount is approx. 4.5 m3/h 
  through feed water system.
- As it was suspected that hydrogen gas had been accumulated inside 
  Primary Containment Vessel, in order to prevent increase in density of 
  oxygen, we commenced the valve opening operation concerning injection of 
  nitrogen gas into the primary containment vessel at 10:30 pm on April 6 
  and commenced injection 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. 
  The current rate of water injection is approx. 5 m3/h through the 
  reactor feed water system piping arrangement. 
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.
  The current rate of water injection is approx. 11.5 m3/h through the 
  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. 
- From 4:05 pm to 7:23 pm on June 18, the injection of fresh water to 
  spent fuel pool of Unit 4 was implemented using temporary water 
  injecting system (hydrazine was also injected from 4:29 pm and completed 
  at 6:33 pm on same day)
- 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. On May 27, we started spraying dust inhibitor to Turbine 
  Building of Units 1, and implemented spraying the dust inhibitor to 
  other turbine and reactor buildings of Units 1 to 4 and completed on 
  June 18th.
- At 2:00 pm on May 1, we started transferring accumulated water in the 
  turbine building of Unit 6 to temporary tanks.
- 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 12:42 pm on June 11, we started to operate local exhausters in order 
  to improve inside environment of Unit 2 Reactor Building.
- 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.
- At 2:20 pm on June17, we started transferring accumulated water in the 
  vertical shaft (trench) of the turbine building of Unit 2 to the 
  condenser in the turbine building of Unit 1. However, at 2:59 pm we 
  stopped the operation of the transfer pump since water flux was not 
  observed. The cause is currently under investigation.
- From 8:00 pm on June17, we started operation of water treatment of 
  accumulated water at accumulated water treatment facility. At 0:54 am on 
  June18, we stopped operation of the facility temporarily due to the 
  radiation dose at surface level measured up to the basis of exchange 
  filter of Cesium adsorption Instruments.
- At 1:31 pm on June 18, we started transfer of accumulated water at 
  basement level in the Unit 3 turbine building to the centralized 
  radiation waste treatment facility (Miscellaneous Solid Waste Volume 
  Reduction Treatment Building).
- From 9:14 am to 11:57 am on June 19, we injected fresh water to the 
  reactor wells and pools for setting temporary equipment of Unit 4 and 
  Unit 5, in order to improve the working environment (to reduce radiation 
  dose) in the 5th floor of the reactor building of Unit 4 and Unit 5. 
- 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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