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Corporate Information

 
Press Release (Jul 04,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 3:00 pm, July 4)
 
*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 approximately 2:30 am on March 23, seawater injection to the reactor through the reactor feed water system was initiated. -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. -At 8:13 am on July 4, we adjusted injection rate from feed water system piping arrangement to approximately 3.8m3 since decrease in amount of water injection was confirmed. -Water is currently injected at approx. 3.8m3/h through reactor feed water system piping arrangement. -We commenced injection of nitrogen gas into Primary Containment Vessel at 1:31am April 7.
 
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. At 6:27 pm on June 23, we changed the water injection line so that we can inject water to Unit 1 and 2 by the motor driven pump for Unit 1 and stopped the motor driven pump for Unit 2. Water is currently injected at approx. 3.5m3/h through reactor feed water system piping arrangement. -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. Water is currently injected at approx. 9 m3/h through reactor feed water system piping arrangement.
 
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. -At this moment, we do not consider any reactor coolant leakage inside the primary containment vessel has occurred.
 
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 (C) in order to cool the spent fuel pool. -At 2:30 pm on March 20, the reactor achieved cold shutdown. -At this moment, we do not consider any reactor coolant leakage inside the primary containment vessel has occurred.
 
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 (B) of Unit 6 in order to cool the spent fuel pool. -At 7:27 pm on March 20, the reactor achieved cold shutdown. -At this moment, we do not consider any reactor coolant leakage inside the primary containment vessel has occurred.
 
Operation for cooling the spent fuel pools -At 5:21 pm on May 31, we started cyclic cooling of the spent fuel pool in Unit 2 using alternative cooling system for fuel pool cooling and filtering system. -At 7:47 pm on June 30, we started cyclic cooling of the spent fuel pool in Unit 3 using alternative cooling system for fuel pool cooling and filtering system. -We will continuously conduct further water spray depending on the conditions of spent fuel pools, if needed.
 
Others -At 1:30 pm on April 26, we started spraying the dust inhibitor inside the site. -At 11:00 am on May 10, we started transferring accumulated water from the underground level of reactor building to the radiation waste treatment facility of Unit 6. -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. -From 8:00 pm on June17, we started operation of water treatment of accumulated water at accumulated water treatment facility. -At 9:56 am on June 22, we started transferring accumulated water in turbine building of Unit 2 to central waste treatment facility building. -At 8:56 am on June 30, we started transferring the accumulated water from the basement of the turbine building of Unit 3 to Centralized Radiation Waste Treatment Facility (Process Building). -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. -From 10:00 am on July 1 to 4:00 pm on July 3, we transferred low radioactive stored water from outdoor temporary tank to Mega Float. We started transferring water again at 1:30 pm on July 4. -From 10:00 am on July 1 to 4:00 pm on July 3, we transferred accumulated water from inside of turbine building of Unit 6 to temporary tank. We restarted the transfer at 10 am on July 4. -At 9:13 am on June 4, we started freshwater injection to reactor well and temporary storage pool of unit 4 to reduce radioactivity concentration of the turbine building 5th floor. -We will continue to take all measures to ensure the safety and to continue monitoring the surrounding environment around the power station.
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