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Corporate Information

 
Press Release (Oct 30,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 3:30 pm, Oct. 30)
 
*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 3:05 pm on October 30, we adjusted the amount of water injected to the 
 reactor approx.6.5 m3/h in order to improve the working condition inside 
 the covers by mitigating the evaporation from the reactor building. 
 The current water injection volume is approx 6.5 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 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. 
 Regarding the hydrogen concentration of the gas management system of the 
 reactor containment vessel in Unit 2, we confirmed that it increased to 
 approx. 2.3vol% at 5:00pm on 29 October, which was approx. 1vol% at the 
 beginning of the operation. Therefore we adjusted the amount of injecting 
 nitrogen gas from approx.14 Nm3/h to 16.5 Nm3/h in order to avoid 
 exceeding the combustible threshold concentration (4vol%) of hydrogen. 
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 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. 
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 and provided medical treatment including operation. At 2:20 pm 
 on the same date, we transported the other worker to Sogo Iwaki Kyoritsu 
 Hospital, Iwaki City and provided medical checkup. 
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. 
-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 10:00 am on October 30, we started transferring accumulated water from 
 the turbine building of Unit 6 to the temporarily build tank. 
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