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Corporate Information

 
Press Release (Feb 21,2012)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 10:00 am, February 21)
  
*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. 4.7 m3/h and that from the core spray system is approx. 1.8 m3/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. 
 - 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 
   feed water system, we started water injection from piping of core spray 
   system to the reactor. 
   With regard to the water injection volume which was increased with 
   temperature figure rising, we adjusted the original volume before 
   temperature increasing (Feed water system: approx. 3.0m3/h, core spray 
   system: approx. 6.0m3/h). At 7:19 pm on February 20, we changed the 
   water injection volume from feed water system from approx.7.6m3/h to 
   approx. 5.6m3/h (The water injection level from core spray system is 
   continuing at approx. 6.0m3/h) 
   The current water injection amount from the reactor feed water system is 
   approx.5.6m3/h and that from the core spray system is approx.6.2m3/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 
   control 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. 
   The current water injection amount from the reactor feed water system is 
   approx. 1.9 m3/h and that from the core spray system is approx. 5 m3/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. 
 - 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. 
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. 
 - 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 9:30 am on February 20, regarding the accumulated water at the 
   basement of Unit 3 Turbine Building, transfer to Centralized Waste 
   Treatment Facility (Miscellaneous Solid Waste Volume Reduction Treatment 
   Building [High Temperature Incinerator Building]) started. 
 - At 9:39 am on February 20, regarding the accumulated water at the 
   basement of Unit 2 Turbine Building, transfer to Centralized Waste 
   Treatment Facility (Miscellaneous Solid Waste Volume Reduction Treatment 
   Building [High Temperature Incinerator Building]) started. 
 - From 10:00 am to 4:00 pm on February 20, we transferred accumulated 
   water from underground floor of turbine building of Unit 6 to temporary 
   tank. At 10:00 am on February 21, we started the transfer. 
 - According to the investigation on trenches on January 19, 2012, high 
   density contaminated water inside was found inside circulating water 
   pump discharge valve pit of Unit 2 water pump room. Therefore, from 
   10:11 am to 5:11 pm on February 20, 2012, we transferred the accumulated 
   water from the pit to the basement of Unit 2 Turbine Building. At 9:50 
   am on February 21, we started the transfer. 
 - At 9:40 am on February 21, at the centralized radiation waste treatment 
   facility, we started transfer of accumulated water from site banker to 
   process main building.  
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