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Corporate Information

 
Press Release (Jul 16,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 10:00 am, July 16)
*Updates from previous press release 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. 
 Water is currently injected at approx. 3.7m3/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. 3.3m3/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.
-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.
-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.
-Regarding the Residual Heat Removal System, we had been utilizing 
 temporary sea water cooling pump, however, at 10:16 am on July 15, we 
 recovered the original Residual Heat Removal System Pump (B)and started 
 it at 2:45 pm. 
-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 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 11:22 on July 12, in order to reduce radiation level on the 5th floor 
 of the reactor building of Unit 4, we started fresh water injection to 
 the reactor well and the pool to put equipment temporarily. However we 
 found water leakage from injection water line and stopped the injection 
 on 12:03 on the same day. As a result of survey, we found water leakage 
 from a connection part with water hose. On July 13, after changing the 
 hose, we started water injection at 11:50 am, but we found water leakage 
 from injection water line and stopped water injection at 12:45 am. After 
 changing the hose, we injected water from 1:05 pm to 7:15pm on July 15.
-From 10:00 am to 5:00 pm on July 15, we transferred low radioactive 
 accumulated water from the outside temporary tanks to Mega Float.
-At 5:14 am on July 15, we stopped the water treatment facility to 
 investigate the cause of reduction from rated water flow. We started the 
 water treatment facility at 2:21 pm and restarted treatment of 
 accumulated water at 2:48 pm, July 15. 
-At 5:28 am, July 16, in order to change the route of the off-site power 
 supply (reinforce the off-site power), we switched the power source of 
 Units 5 and 6 to diesel generators (two). 
-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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