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Corporate Information

 
Press Release (Jun 06,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 10:00 am, June 6)
  
 
*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 powered by the off-site transmission line. We are now 
 injecting freshwater by a motor driven pump powered by the off-site 
 transmission line. 
 The current rate of water injection is approx. 5 m 3/h through reactor 
 feed water system piping arrangement. 
-As it was suspected that hydrogen gas had been accumulated inside Primary 
 Containment Vessel, we commenced the valve opening operation concerning 
 injection of nitrogen gas into the primary containment vessel at 10:30 pm 
 on April 6 and commenced injection 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 
 and are now injecting freshwater by a motor driven pump powered by the 
 off-site transmission line. 
 The current rate of water injection is approx. 5 m3/h through the reactor 
 feed water system piping arrangement. 
 
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. 
 The current rate of water injection is approx. 11.5 m3/h through the 
 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. 
-From 1:08 pm to 3:14 pm on June 5, we conducted the water injection to 
 the spent fuel pool of Unit 3 by a temporary motor driven pump (from 1:14 
 pm to 2:16 pm, we added hydrazine (antioxidant)). 
-We will continuously conduct further water spray depending on the 
 conditions of spent fuel pools, if needed. 
 
Injured person etc. 
-At around 10:00 am on June 5, because one of the workers of cooperative 
 firm who were conducting power cable laying operation in the power 
 station yard complained of bad health, we airlifted him to Iwaki Kyoritsu 
 Hospital by Helicopter Emergency Medical Service. 
-And, at around 10:15 am on June 5, because another worker of cooperative 
 firm who were conducting the same operation also complained of bad health, 
 we took him to Fukushima Rosai Hospital by ambulance. 
 
Others 
-At 1:30 pm on April 26, we started spraying the dust inhibitor inside the 
 site. 
 On May 27, we started spraying dust inhibitor to Turbine Building of 
 Units 1. We will implement spraying the dust inhibitor to other turbine 
 and reactor buildings of Units 1 to 4. 
-At 2:00 pm on May 1, we started transferring accumulated water in the 
 turbine building of Unit 6 to temporary tanks. 
-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 6:39 pm on June 4, we started transferring accumulated water from 
 vertical shafts (trenches) of turbine building of Unit 2 to Process Main 
 Building. 
-At 6:26 pm on June 5, we started transferring accumulated water from the 
 turbine building of Unit 3 to the condenser. 
-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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