Print

Language



Corporate Information

 
Press Release (May 07,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 10:00 am, May 7)

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 nuclear 
  reactor through the feed water system was initiated.
- From 3:37 pm on March 25, we started injecting freshwater and are now 
  injecting fresh water by a motor driven pump powered by the off-site 
  transmission line. From on April 27, we have increased the amount of 
  injecting freshwater from approximately 6 m3/h to approximately 14 m3/h. 
  At 10:14 am on April 29, we put the amount of injecting freshwater back 
  to approximately 6 m3/h.
- As it is suspected that hydrogen gas is accumulated inside reactor 
  containment vessel, we commenced the valve opening operation concerning 
  injection of nitrogen gas into the reactor container vessel at 10:30 pm 
  April 6th and commenced injection at 1:31am April 7.
- At 10:01 am on May 6th, in order to make nuclear reactor flooded to the 
  top of Fuel range, we have increased the amount of injecting freshwater 
  from approximately 6 m3/h to approximately 8m3/h. 
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. 
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. 
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 the 
  Nuclear Reactor Building.
- At this moment, we do not consider any reactor coolant leakage inside 
  the reactor happened. 
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 reactor cold shutdown. 
- At this moment, we do not consider any reactor coolant leakage inside 
  the reactor happened. 
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 reactor cold shutdown. 
- At this moment, we do not consider any reactor coolant leakage inside 
  the reactor happened. 
Operation for cooling the spent fuel pools 
- From 12:38 pm to 5:51pm on May 6th, we conducted water spay to Unit 4 by 
  the concrete pumping vehicle.
- We will continuously conduct further water spray depending on the 
  conditions of spent fuel pools, if needed. 
Others 
- The transfer of high level radioactive wastewater in Unit 2 to the 
  Centralized Radiation Waste Treatment Facility was temporarily suspended 
  at 9:22am on May 7th, due to the construction of injection piping 
  (reactor feeding water system) to reactor of unit3. 
- The transfer of accumulated water in Unit 6 turbine building to a 
  temporary tank was conducted from 2:00 pm to 5:00 pm on May 3.
- From March 27, transfer of accumulated water in Unit 5 turbine building 
  to a condenser has been conducted, and water with the amount of 
  approximately 600m3 has been transferred from March 27 to May 2.
- From May 2, we have started work relating to the set up of exhausters, 
  in order to improve the working environment inside the reactor building 
  of Unit 1. At 4:36 pm on May 5th, all of exhausters(6 units) were 
  started to operation. 
- The transfer of accumulated water in Unit 6 turbine building to a 
  temporary tank was conducted from 2:00 pm to 5:00pm on May 6th.
  The transfer of accumulated water in Unit6 turbine building to a 
  temporary tank was started at 10:00am May 7th. 
- 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