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Press Release (Sep 21,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 10:00 am, Sep. 21)
 
*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. - From 3:37 pm on March 25, we started injecting freshwater by a motor driven pump which is now powered by the off-site transmission line. Water is currently injected at approx. 3.7 m3/h through reactor feed water system piping arrangement. - We commenced injection of nitrogen gas into Primary Containment Vessel at 1:31am on April 7. - At 11:22 pm 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.
 
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. - From 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. 3.6 m3/h through reactor feed water system piping arrangement, and at approx. 4.1 m3/h through core spray system water injection piping arrangement. - From 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.
 
Unit 3 (Shut down) - Explosive sound and white smoke were confirmed at approximately 11:01am on March 14. It was assumed to be hydrogen explosion. - From 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. - From 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. 3.9 m3/h through reactor feed water system piping arrangement, and at approx. 8.2 m3/h through core spray system water injection piping arrangement. - From 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 approximately 6:00 am on March 15, we confirmed the explosive sound and the sustained damage around the 5th floor rooftop area of Reactor Building. - From 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. - From 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.
 
Others - At approximately 10:00 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 8:00 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 9:51 am on September 13, we started transferring accumulated water from the turbine building of Unit 2 to High Temperature Incinerator Building of Centralized Radiation Waste Treatment Facility. - At 9:54 am on September 15, we started transfer of the accumulated water from the turbine building of Unit 3 to Centralized Radiation Waste Treatment Facility. - From 10:00 am to 4:00 pm on September 20, we transferred the accumulated water from the turbine building of Unit 6 to temporary tanks. At 10:00 am on September 21, we started again.
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