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Corporate Information

 
Press Release (Nov 15,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 3:00 pm, November 15)
  
* 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 3:37 pm on March 25, 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. 
  The current water injection volume is approx 7.8 m3/h from the reactor 
  feed water system. 
- We commenced injection of nitrogen gas into Primary Containment Vessel at 
  1:31 am on April 7. 
- At 11:22 am on August 10, 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, we completed installation of the cover for the Reactor 
  Building in order to contain dispersion of radioactive substances. 
 
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. 
- At 10:10 am on March 26, 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, we started injecting water to the reactor 
  through core spray system water injection piping arrangement in addition 
  to the water injection through reactor feed water system piping arrangement. 
  Water is currently injected at approx. 2.8 m3/h through reactor feed 
  water system piping arrangement, and at approx. 7.3 m3/h through core 
  spray system water injection piping arrangement. 
- At 5:21 pm on May 31, 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, we started injecting nitrogen gas into the Primary 
  Containment Vessel. 
- From 6:00 pm on October 28, we put the gas management system of the 
  reactor containment vessel in operation. On November 14, we implemented 
  sampling survey of gas at gas management system of Unit 2 primary 
  containment vessel. According to its analysis, it is considered that 
  recriticality was not occurred because radioactive Xe-135 at the entrance 
  of gas management system of Unit 2 was below the detection limit 
  (9.2x10-2Bq/cm3) 
- At 11:04 am on November 6, we started operation of radioactive material 
  decontamination instrument of spent fuel pool. 
 
Unit 3 (Shut down) 
- Explosive sound and white smoke were confirmed at approximately 11:01 am 
  on March 14. It was assumed to be hydrogen explosion. 
- At 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. 
- At 2:58 pm on September 1, we started water injection by core spray 
  system in addition to water injection by the reactor feed water system 
  piping arrangement. 
  Water is currently injected at approx. 2.7 m3/h through reactor feed 
  water system piping arrangement, and at approx. 8.1 m3/h through core 
  spray system water injection piping arrangement. 
- At 7:47 pm on June 30, 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, injection of nitrogen gas into the Primary 
  Containment Vessel started. 
 
Unit 4 (Outage due to regular inspection) 
- At around 6 am on March 15, 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, 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 11:34 am on August 20, we started an operation of desalination 
  equipment in the spent fuel pool. 
- 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, we started the Residual Heat Removal System Pump 
  in order to cool the spent fuel pool. 
- At 2:30 pm on March 20, the reactor achieved cold shutdown. 
- At 2:45 pm on July 15, we started the operation of the original Residual 
  Heat Removal System (System B) by its original seawater pump. 
- 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, we started the Residual Heat Removal System Pump 
  of Unit 6 to cool down Spent Fuel Pool. 
- At 7:27 pm on March 20, the reactor achieved cold shutdown. 
- At 2:33 pm on September 15, 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 time, we don't think there is any reactor coolant leakage inside 
  the primary containment vessel. 
- From November 15, due to cleanup work in order to prevent performance 
  deterioration of pump caused by inletting sand or other materials piled 
  up at the bottom of pump room of intake channel, Residual Heat Removal 
  System (A) was shutdown, and stopped cooling the reactor. And Seawater 
  pump of Equipment Water Cooing System (A) was shutdown, and stopped 
  cooling the spent fuel pool. The stop is scheduled from 7:00 am to 5:00 
  pm everyday, and reactor water temperature will rise by approx. 12°C per 
  day, and spent fuel pool water temperature will rise by approx. 3°C per 
  day. (The cleanup work is planned to be finished in a week.) 
 
Others 
- At around 10 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 8 pm on June 17, 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, 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, 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, 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 9:10 am on November 10, we started transfer of accumulated water from 
  the basement of Unit 2 turbine building to Centralized Radiation Waste 
  Treatment Facility High Temperature Incinerator Building. 
- At 9:25 am on November 15, we started transfer of accumulated water from 
  basement of Unit 3 turbine building to Centralized Radiation Waste 
  Treatment Facility Building. 
- At 9:30 am on November 15, at the emergency feed water injection lines of 
  Units 1 to 3, in preparation for the installation of flow control valves 
  to increase the water flow controllability, in order to secure a place to 
  install, we started transfer of a truck on which to load an emergency 
  diesel generator located upland for feed water injection. At 10:37 am on 
  the same day, the transfer of track finished. In line with the transfer 
  we disconnected and then reconnected the power line. Although the diesel 
  generator became unready due to the transfer of track, there is no effect 
  caused by the installation work because we continue water injection into 
  the reactor with the regular-use feed water pump located upland.  
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