search



Corporate Information

 
Press Release (Aug 20,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 10:00 am, Aug. 20)
All 6 units of Fukushima Daiichi Nuclear Power Station have been shut down. 
*New items are underlined 
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. 3.7 ㎥/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 9:00 am on August 10, we started to assemble steel frame for the 
 Reactor Building Cover. 
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 3:30 pm on August 19, as we confirmed decrease in the rate of water 
 injection to the reactor, we adjusted the rate of water injection through 
 reactor feed water system piping arrangement to approximately 3.8㎥. 
 Water is currently injected at approx. 3.7 ㎥/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. 8 ㎥/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 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 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 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 Pump (B).
-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 this time, we don't think there is any reactor coolant leakage inside 
 the primary containment vessel. 
Operation for cooling the Spent Fuel Pools 
-At 5:21 pm on May 31, we started cyclic cooling of Spent Fuel Pool of 
 Unit 2 by using alternative cooling system of the Pool's cooling and 
 filtering system.
-At 7:47 pm on June 30, we started cyclic cooling of Spent Fuel Pool of 
 Unit 3 by using alternative cooling system of the Pool's cooling and 
 filtering system.
-At 12:44 pm on July 31, we started cyclic cooling of Spent Fuel Pool of 
 Unit 4 by using alternative cooling system of the Pool's cooling and 
 filtering system.
-At 11:22 am on Aug 10, we started cyclic cooling of Spent Fuel Pool of 
 Unit 1 by using alternative cooling system of the Pool's cooling and 
 filtering system. 
Others 
-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 around 10 am on June 13, we started the operation of the circulating 
 seawater purification facility installed at the screen area of Units 2 
 and 3.
-At 8:00 pm on June 17, we started operation of Water Treatment Facility 
 against the accumulated water. At 3:50 pm on August 18, we added the 2nd 
 cesium adsorption instrument and started to treat 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.
-From 10:00 am to 5:00 pm on August 18, we transferred accumulated water 
 from the turbine building of Unit 6 to a temporary tank.
-At 4:19 pm on August 18, we transferred accumulated water from the 
 turbine building of Unit 2 to Central Radioactive Waste Treatment 
 Facility.
-At 8:51 am on August 19, we transferred accumulated water from the 
 turbine building of Unit 3 to Central Radioactive Waste Treatment 
 Facility. 
-At 2:00 pm on August 19, we stopped operation of Water Treatment Facility 
 in order to transition to parallel operation of the line from cesium 
 adsorption instrument to decontamination instrument and the line of 2nd 
 cesium adsorption instrument. Afterward at 3:44 pm we started operation 
 of the line from cesium adsorption instrument to decontamination 
 instrument, and at 3:54 pm we started to treat the accumulated water. And 
 at 7:33 pm we started operation of the treatment line of 2nd cesium 
 adsorption instrument, and at 7:41 pm we started to treat the accumulated 
 water by parallel operation. 
back to page top


to TOP