search



Corporate Information

 
Press Release (May 04,2011)
Plant Status of Fukushima Daiichi Nuclear Power Station (as of 10:00 am, May 4)
Updates 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 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.  
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 
- We will continuously conduct further water spray depending on the
  conditions of spent fuel pools, if needed.  
Others 
- Regarding the transfer of high level radioactive wastewater in Unit 2
  to the Centralized Radiation Waste Treatment Facility, while we
  temporarily suspended transfer due to the inspection of transferring
  facilities at 9:16 am on April 29, transfer was restarted at 2:05pm on
  April 30.
- 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. 
- 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