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Corporate Information

 
Press Release (Feb 01,2012)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 3:00 pm, February 1)
* The 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, 2011. It was assumed to be hydrogen 
  explosion.
- At 3:37 pm on March 25, 2011, 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. 
  At 10:11 am on December 10, 2011, in addition to water injection from 
  water feeding system, we started water injection from piping of core 
  spray system to the reactor.
  The current water injection amount from the reactor feed water system is 
  approx. 4.4m3/h and that from  the core spray system is approx. 2m3/h.
- At 1:31 am on April 7, 2011, we commenced injection of nitrogen gas into 
  Primary Containment Vessel.
- At 11:22 am on August 10, 2011, we started cyclic cooling for the water 
  in the spent fuel pool by an alternative cooling equipment of the Fuel 
  Pool Cooling and Filtering System. 
  At 3:05 pm on January 30, we stopped the operation of the secondary 
  air-fin coolers of spent fuel pool in order to prevent overcooling of 
  alternative cooling system of spent fuel pool of Unit 1. (the temperature 
  of fuel pool at the time of stoppage: 12°C)
- On October 28, 2011, we completed installation of the cover for the 
  Reactor Building in order to contain dispersion of radioactive substances.
- At 4:04 pm on November 30, 2011, we started operation to inject nitrogen 
  into the reactor pressure vessel.
- At 6:00 pm on December 19, 2011, a full-scale operation of the PCV gas 
  management system started.   
Unit 2 (Shut down)  
- At approximately 6:00 am on March 15, 2011, an abnormal noise began 
  emanating from nearby Pressure Suppression Chamber and the pressure 
  within the chamber decreased. 
- At 10:10 am on March 26, 2011, 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. 
- At 2:59 pm on September 14, 2011, in addition to water injection from 
  water feeding system, we started water injection from piping of core 
  spray system to the reactor.
  After we finished replacing the water injection line from the reactor 
  water injection pump on the hill to polyethylene pipe in order to improve 
  the reliability of water injection to the reactor, we have been changing 
  the water injection volume to the reactor gradually. At 11:50 pm on 
  February 1, we adjusted the water injection volume to the reactor through 
  the feed water system from approx. 5 m3/h to approx. 4 m3/h, and the 
  volume from the reactor core spray system from approx. 4 m3/h to approx. 
  5m3/h.   
  At 5:10 pm on January 25, regarding the reactor injection from the feed 
  water system at the Unit 2, we changed the injection line from the pump 
  located uphill to the T/B reactor injecting pump. 
  The current water injection amount from the reactor feed water system is 
  approx. 4m3/h and that from the core spray system is approx. 5m3/h.
- At 5:21 pm on May 31, 2011, we started cyclic cooling for the water in 
  the spent fuel pool by an alternative cooling equipment of the Fuel Pool 
  Cooling and Filtering System. 
- At 8:06 pm on June 28, 2011, we started injecting nitrogen gas into the 
  Primary Containment Vessel.
- At 6:00 pm on October 28, 2011, a full-scale operation of the PCV gas 
  management system started.
- At 10:46 am on December 1, 2011, we started the nitrogen injection to the 
  Reactor Pressure Vessel.
- At 11:50 am on January 19, 2012, we started the operation of the spent 
  fuel pool desalting facility.   
Unit 3 (Shut down)  
- Explosive sound and white smoke were confirmed at approximately 11:01 am 
  on March 14, 2011. It was assumed to be hydrogen explosion.
- At 6:02 pm on March 25, 2011, 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.
- At 2:58 pm on September 1, 2011, we started water injection by core spray 
  system in addition to water injection by the reactor feed water system 
  piping arrangement. 
  At 3:01 pm on January 27, the water injection to the reactor from the 
  feed water injection system was switched from the reactor water injection 
  pump in the turbine building to the reactor water injection pump on the 
  hill.
  After we finished replacing the water injection line from the reactor 
  water injection pump on the hill to polyethylene pipe in order to improve 
  the reliability of water injection to the reactor, we have been changing 
  the water injection volume to the reactor gradually. At 11:50 pm on 
  February 1, we adjusted the water injection volume to the reactor through 
  the feed water system from approx. 5 m3/h to approx. 4 m3/h, and the 
  volume from the reactor core spray system from approx. 4 m3/h to approx. 
  5m3/h.   
  The current water injection amount from the reactor feed water system is 
  approx. 4m3/h and that from the core spray system is approx. 5m3/h.
- At 7:47 pm on June 30, 2011, we started cyclic cooling for the water in 
  the spent fuel pool by an alternative cooling equipment of the Fuel Pool 
  Cooling and Filtering System.
  Regarding the water leakage from Filtrate water supply valve of Unit 3 
  spent fuel pool cooling system occurred on January 29, we removed the 
  valve and completed installation of blanking plate. In addition, we are 
  suspending the secondary cooling tower in order to prevent overcooling of 
  spent fuel pool alternative cooling facility. 
- At 8:01 pm on July 14, 2011, injection of nitrogen gas into the Primary 
  Containment Vessel started. 
- At 4:26 pm on November 30, 2011, we started operation to inject nitrogen 
  into the reactor pressure vessel.
- At 3:18 pm on January 14, we started operation of the radioactive 
  material removal instrument for the spent fuel pool in Unit 3   
Unit 4 (Outage due to regular inspection)  
- At around 6 am on March 15, 2011, we confirmed the explosive sound and 
  the sustained damage around the 5th floor rooftop area of Reactor 
  Building.
- At 12:44 pm on July 31, 2011, we started cyclic cooling for the water in 
  the spent fuel pool by an alternative cooling equipment of the Fuel Pool 
  Cooling and Filtering System.
- At 10:58 am on November 29, 2011, in order to decrease more salinity, we 
  installed Ion exchange equipment and started the operation of such 
  equipment.
- 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, 2011, we started the Residual Heat Removal System 
  Pump in order to cool the spent fuel pool.
- At 2:45 pm on July 15, 2011, we started the operation of the original 
  Residual Heat Removal System (System B) by its original seawater pump.
- At 10:11 am on December 22, 2011, since we finished the recovery work of 
  seawater pump (System B) of equipment water cooling system, we made a 
  trial run. At 11:25 am on the same day, we confirmed no abnormalities and 
  restarted the operation.
- At this moment, 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, 2011, we started the Residual Heat Removal 
  System Pump of Unit 6 to cool down Spent Fuel Pool.
- At 2:33 pm on September 15, 2011, we started separately cooling the 
  reactor through the Residual Heat Removal System and the spent fuel pool 
  through Equipment Cooling Water System and Fuel Pool Cooling System.
- At this moment, we do not think there is any reactor coolant leakage 
  inside PCV.   
Others  
- At around 10:00 am on June 13, 2011, 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, 2011, 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, 2011, 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 
  cesium adsorption instrument No.2.
- At 2:06 pm on October 7, 2011, we started to spray purified accumulated 
  water brought from Unit 5 and 6 continually in order to prevent dust 
  scattering and potential fire outbreaks from the cut down trees.
- On October 28, 2011, we started installation of the water proof wall at 
  the sea side, in front of the existing shore protection, Units 1-4, in 
  order to contain marine pollution by underground water.
- At 12:25 pm on December 13, 2011, we started the re-circulating operation 
  of desalination facility (reverse osmosis membrane type) for the purpose 
  of suppression of condensed water after desalination treatment.
- As finding of accumulated water containing radioactive materials at the 
  trench between the Process Main Building and the Miscellaneous Solid 
  Waste Volume Reduction Treatment Building [High Temperature Incinerator 
  Building] (December 18, 2011), we started the inspection of other 
  trenches at the site on January 11.
- At 4:05 pm on January 30, we started to transfer the accumulated water 
  from the basement of T/B, Unit 2 to the Centralized Waste Treatment 
  Facility (Miscellaneous Solid Waste Volume Reduction Treatment Building 
  [High Temperature Incinerator Building] and Process Main Building) 
  through newly installed polyethylene pipes.
- At 4:12 pm on January 30, we started to transfer the accumulated water 
  from the basement of T/B, Unit 3 to the Centralized Waste Treatment 
  Facility (Miscellaneous Solid Waste Volume Reduction Treatment Building 
  [High Temperature Incinerator Building] and Process Main Building) 
  through newly installed polyethylene pipes.
- At 10:00 am on February 1, we started transfer of the accumulated water 
  from Unit 6 Turbine Building to temporary tanks.
- At 9:18 am on January 31, we started transfer of Sub-drain Water of Unit 
  6 to the temporary tank. We will conduct transferring to the temporary 
  tank appropriately.
- At approx. 10:30 pm on January 31, we found that the water was leaking 
  from the indicator test line in the rack instruments for jet pumps were 
  stored on the first floor in Unit 4 Reactor Building. At 10:43 pm, the 
  leakage was stopped after the main valve leading to the rack was closed. 
  Debris were scattered around on the floor, and the volume of leaked water 
  was approx. 6 litters as far as we could confirmed. Please note that it 
  didn't run off outside of the reactor building. We sampled the water in 
  the test line and measured the radioactivity concentration. From the 
  results, we estimated the water leaked from the reactor well (analysis 
  result: 35.5 Bq/cm3).
- Newly found water leakage after the previous announcement (as of 3:00 pm 
  January 31) is as follows; 
  · Casing of the water injection pump (electrically driven pump for Unit 
    2) at the side of the pure water tank (found approx. at 4:00 pm on 
    January 31) 
    (Filtrate water*: approx. 10 L) 
    * Filtrate water: water taken from the dam
  · Indicator (flow rate transmitter) test line in the instrument rack 
    (instrument rack for the jet pump) at the southwest corner on the first 
    floor of Unit 4 Reactor Building (found approx. at 10:30 pm on January 
    31) (Water from the reactor well: approx. 6 L) 
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