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Corporate Information

 
Press Release (Oct 29,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 3:00 pm, Oct. 29)
 
*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.
- At 4:10 pm on October 28, in order to ensure containing steam generation 
  and to make the working environment better in the covering of the 
  Reactor Building, we increased the water injection to the Reactor via 
  the reactor feed water system from 3.8 m3/h to 4.5 m3/h. 
  The current water injection volume is approx 4.3 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. 2.8m3/h through reactor feed 
  water system piping arrangement, and at approx. 7 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.
- At 10:30 am on October 27, we conducted leak test of the system as a 
  part of construction to settle the gas control system of Primary 
  Containment Vessel at the reactor building of Unit 2. As a result, we 
  confirmed in-leak volume to the system had no problem. In addition, we 
  conducted tentative operation test. As a result, we confirmed 
  operational aspect of electric heater and exhaust fun had no problem.
  At 12:53 pm on October 28, we activated the exhaust fan of the gas 
  management system of the reactor containment vessel in the reactor 
  building and started test operation. As we confirmed stable operation of 
  the system, from 6:00 pm on the same day, we put the system in operation. 
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. 2.6 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 time, 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. 
Injuries 
- At 8:30 am on October 29, two workers from the cooperating companies 
  were injured during dismantling of the large crane used to install the 
  cover for the Reactor Building, Unit 1 within the site boundary. At 9:50 
  am, one worker departed the emergency room, Units 5 and 6 and will be 
  transported to a hospital by an air ambulance. The other worker will be 
  transported to the hospital by a company vehicle. At 10:35 am on October 
  29, we transported one worker to Fukushima Medical University Hospital 
  by an air ambulance. At 2:20 pm on the same date, we transported the 
  other worker to Sogo Iwaki Kyoritsu Hospital, Iwaki City. 
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.
- At 10:12 am on October 20, we started transferring the accumulated water 
  from the basement of turbine building of Unit 2 to the Process Main 
  Building of Central Radioactive Waste Treatment Facility. At 9:32 am on 
  October 28, we stopped transferring the accumulated water from the 
  basement of turbine building of Unit 2 to the Process Main Building of 
  Central Radioactive Waste Treatment Facility temporarily, and after 
  checking the systematic diagram, at 9:54 am on October 28 we changed the 
  destination of transferring the accumulated water to High Temperature 
  Incinerator Building of Centralized Radiation Waste Treatment Facility. 
- From 10:00 am to 4:00 pm on October 28, we transferred accumulated water 
  from temporary tanks to Mega Float.
- 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. 
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