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Corporate Information

 
Press Release (Feb 01,2012)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 10:00 am, 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.
- 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 11:25   
  pm on January 31, we adjusted the water injection volume to the reactor   
  of Unit 1 through the feed water system from approx. 5.8 m3/h to approx.  
  4.5 m3/h, and the volume from the reactor core spray system from approx.  
  0.9 m3/h to approx. 2.0m3/h.   
  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.
  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. 5.1m3/h and that from the core spray system is approx. 4m3/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.
  The current water injection amount from the reactor feed water system is
  approx. 5m3/h and that from the core spray system is approx. 4m3/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.
  Places the accumulated water was found by the inspection on January 31  
  and its nuclide analyses results (provisional) are as follows;    
    ·Discharge pit of the circulation water pump in the pump room, Unit 4     
     I-131: Below detection limit, Cs-134: 4.5X100Bq/cm3,  
     Cs-137: 6.3X100Bq/cm3   
    ·Cable duct at the start-up transformer, Unit 1     
     I-131: Below detection limit, Cs-134: 2.2X100Bq/cm3,   
     Cs-137: 3.0X100Bq/cm3   
    ·We confirmed that no water was accumulated in the trench on the  
     north of former Administration Office Building.  
- 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.
- From 9:35 am to 3:33 pm on January 31, we transferred the accumulated
  water from site bunker to process main building in the centralized
  radiation waste treatment facility.
- From 10:00 am to 4:00 pm on January 31, we transferred the accumulated
  water from the basement of turbine building of Unit 6 to temporary tanks.
- 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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