search



Corporate Information

 
Press Release (Jul 17,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 10:00 am, July 17)
*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. 3.4m3/h through reactor feed water
  system piping arrangement.
- We commenced injection of nitrogen gas into Primary Containment Vessel at
  1:31am on 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 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 10:50 am on July 16, we started transfer of the accumulated water from
  the Turbine Building of Unit 3 to the Process Main Building of the 
  Centralized Radiation Waste Treatment Facility.
- At 10:56 am on July 16, we started transfer of the accumulated water from
  the Turbine Building of Unit 2 to the Process Main Building of the 
  Centralized Radiation Waste Treatment Facility.
- From 11:22 am to 3:52 pm on July 16, we injected fresh water into the 
  Reactor Well and the Drier Separator Pit of Unit 4, in order to reduce 
  the radiation dose at the 5th floor of the Unit 4 Reactor Building.
- At 4:24 am on July 17, in accordance with the operation for transmission 
  rerouting of the offsite power for Unit 5 and 6 (enhancement of offsite 
  power), we switched the on-site power for Unit 5 and 6 to power receiving 
  from two diesel generators. 
- We will continue to take all measures to ensure the safety and to 
  continue monitoring the surrounding environment around the power station. 
back to page top


to TOP