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Corporate Information

 
Press Release (Nov 17,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 3:00 pm, November 17)
 
* 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 7.6m3/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. 2.7 m3/h through reactor feed water system piping arrangement, and at approx. 7.4 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. - We have been conducting gas analysis by using PCV gas management system since October 28, 2011. However, it was found that some measurement results collected on October 28, November 1, 2 and 14 were evaluated about 10% lower in terms of the concentration of radioactive materials due to computation process error. The error is limited to figures only, and does not affect the criterion of criticality resumption nor evaluation results. - 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. 2.5 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. - From 1:32 pm to 2:55 pm on November 17, to clean primary system strainer by back wash, in order to deal with an alarm indicating decrease of alternative cooling primary system pump suction pressure at the spent fuel pool (SFP) alternative cooling was temporarily stopped. (SFP water temperature when stopped: approx. 19.2°C, SFP water temperature when restarted: 18.8°C * as skimmer surge tank water decreased influenced by outside air, it is presumed that temperature decreased compared with the time it stopped)
 
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. (Hydrazine was also injected from 1:15 pm to 2:50 pm on November 17) - At 11:34 am on August 20, we started an operation of desalination equipment in the spent fuel pool. - At 2:58 pm on November 17, an error alarm of spent fuel pool alternative cooling system went off, and the system automatically shut down. We are currently investigating the cause of alarm. - 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, we started 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.
 
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 10:00 am on November 17, we started transfer of accumulated water from Unit 6 turbine building to temporary tanks. - From 9:15 am to 1:09 pm on November 17, at unit 1 and 2 emergency reactor injection line, flow amount adjusting valve was additionally installed to control the amount of water injection. Water injection to reactor is done through regular reactor water injection line, and therefore the additional installation above has no impact. - At around 10:50 am November 17, a partner company worker confirmed water leakage by pin holes at one point of freshwater transfer line, and three points at concentrated water transfer line of desalination apparatus (RO method). At around 2:30 pm, while transfer was continued at fresh water transfer line, at the same time, leakage repair (repair by tapes) was implemented and completed (leakage amount: little). Leakage was also repaired at concentrated water transfer line (leakage amount: 1 liter). Cesium adsorption apparatus, 2nd adsorption apparatus and concentrated evaporation apparatus continued operation, and therefore there is no major effect with processing accumulated water. Also, concentrated water transfer line is currently not being used, and is isolated.
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