search



Corporate Information

 
Press Release (Aug 03,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 3:00 pm, Aug 3)
*New items 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. 3.8 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.
  From 5:52 am to 8:33 am on August 3, the nitrogen gas supply was stopped 
  due to switching work of nitrogen gas injection equipment to spare one.
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. 
  Water is currently injected at approx. 3.7 m3/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.
  From 5:52 am to 8:29 am on August 3, the nitrogen gas supply was stopped 
  due to switching work of nitrogen gas injection equipment to spare one. 
  (However, from 5:38 am to 8:27 am, the nitrogen gas injection was 
  continued by using alternative gas supply line.)
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. 9.1 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.
  From 5:52 am to 8:29 am on August 3, the nitrogen gas supply was stopped 
  due to switching work of nitrogen gas injection equipment to spare one.
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 (C) 
  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 0:44 am on July 31, we started cyclic cooking of Spent Fuel Pool of 
  Unit 4 by using alternative cooling system of the Pool's cooling and 
  filtering system.
Others 
- At 11 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 Unit 2 
  and 3.
- At 8 pm on June 17, we started operation of Water Treatment Facility 
  against the accumulated water. 
- At 6 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 4:10 pm on July 30 to 6:49 pm on August 2, we transferred 
  accumulated water at Unit 2 turbine building to Centralized Radiation 
  Waste Treatment Facility.
- From 4:13 pm on July 30, we started transferring accumulated water at 
  Unit 3 turbine building to Centralized Radiation Waste Treatment Facility.
- From 10 am to 5 pm on August 2, we transferred low level accumulated 
  water from temporary outside tank to mega-float.
- At 10 am on August 3, we started transferring of low level accumulated 
  water from temporary outside tank to mega-float.
- From 11 am to 4 pm on August 2, we transferred accumulated water from 
  Unit 6Turbine Building to the temporary tank. 
- At 11 am on August 3, we started transferring accumulated water from 
  Unit 6 Turbine Building to the temporary tank.
back to page top


to TOP