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Corporate Information

 
Press Release (Feb 15,2012)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 3:00 pm, February 15)
 *There are no updates. 
 
 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. 4.3 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. 
 Because the tendency of temperature rise at the bottom of PCV had been 
 accelerated since February 2, we increased the amount of water injected 
 to the reactor and continued monitoring the tendency of the temperature 
 fluctuation. 
-On February 14, sampling for the air of Unit 2 PCV gas control system was 
 conducted. As a result of the analysis, it was confirmed that xenon 135 
 at the entrance of the system was below the detection limit (1.0x10-1 
 Bq/cm3) and recriticality criteria 1 Bq/cm3. Thus, recriticality was not 
 confirmed. 
 The current water injection amount from the reactor feed water system is 
 approx.7.6 m3/h and that from the core spray system is approx.10 m3/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. 
-On February 13, sampling was conducted for charcoal filter of Unit 2 PCV 
 gas control system. 
-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. 3 m3/h and that from the core spray system is approx. 6 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. 
 Since 9:50 am on February 10, we have conducted the work to add flow 
 meters to the nitrogen injection line at the side of Primary Containment 
 Vessel of Unit 3 in order to improve the reliability of nitrogen 
 injection activity. During this period, due to this work, we suspended 
 the nitrogen injection task temporarily. 
-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. 
-In order to conduct inspection of the strainer changeover valve of the 
 pump of the reactor sea water system of Unit 6 from February 14 to 
 February 17, at 10:02 am on February 14, we stopped cooling of the spent 
 fuel pool by the spent fuel pool cooling system (B) and at 10:06 am on 
 the same day, we stopped the pump of the reactor sea water system (A) 
 (spent fuel pool water temperature during the stoppage: approx. 23°C). 
 Because the spent fuel pool cooling system isn't in operation during the 
 inspection, we conduct alternating cooling of the reactor and the spent 
 fuel pool by the residual heat removal system. The water temperature in 
 the reactor and the spent fuel pool are expected to rise up to 37°C and 
 31°C respectively during the inspection, but in terms of the temperature 
 raise, we estimate that it is not a problem. 
-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 accumulated water containing radioactive materials was found in the 
 trench between Process Main Building and Miscellaneous Solid Waste Volume 
 Reduction Treatment Building (High Temperature Incinerator Building) in 
 Centralized Radiation Waste Treatment Facility (December 18, 2011), 
 inspection of other trenches in the site was commenced from January 11. 
-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 2:43 pm on February 10, we started to transfer accumulated water from 
 underground floor of turbine building of Unit 2 to centralized radiation 
 waste treatment facility (Miscellaneous Solid Waste Volume Reduction 
 Treatment Building [High Temperature Incinerator Building]). 
-At 9:57 am on February 12, we started to transfer accumulated water in 
 the underground of turbine building of Unit 3 to the Centralized 
 Radiation Waste Treatment Facility (Process Main Building). 
-At 10:00 am to 4:00 pm on February 14, we transferred accumulated water 
 at the basement of turbine building of unit 6 to temporary tank. At 10:00 
 am on February 15, we resumed the transfer. 
-At 8:52 am on February 14, water flow at the 2nd Cesium adsorption 
 apparatus tends to decrease, so we stopped it to wash the inside of the 
 device by reversing the water flow. 
-From 11:45 am to 1:45 pm on February 13, dust sampling was conducted for 
 Unit 2 reactor building opening (Blowout panel). 
-At 10:00 am on February 15, we started the transfer of accumulated water 
 from the basement of turbine building of unit 6 to temporary tank.  
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