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Corporate Information

 
Press Release (Mar 14,2011)
Plant Status of Fukushima Daini Nuclear Power Station (as of 8:00 am March 14th)
 
[New Items are underlined] 
 
Unit 1 (shut down at 2:48pm on March 11th)
- Reactor is shut down and reactor water level is stable.
- Offsite power is available.
- At 8:19am, Mar 12th, there was an alarm indicating that one of the 
  control rods was not properly inserted, however, at 10:43am, Mar 12th 
  the alarm was spontaneously called off. Other control rods has been 
  confirmed that they are fully inserted (reactor is in subcritical 
  status)
- Status of main steam isolation valve: closed
- Injection of water into the reactor is done by Make-up Water Condensate 
  System.
- We do not believe there is leakage of reactor coolant in the containment 
  vessel at this moment.
- At 5:22am, Mar 12th, the temperature of the suppression chamber exceeded 
  100 degrees. As the reactor pressure suppression function was lost, at 
  5:22am, Mar 12th, it was determined that a specific incident stipulated 
  in article 15, clause 1 has occurred.
- We decided to prepare implementing measures to reduce the pressure of 
  the reactor containment vessel (partial discharge of air containing 
  radioactive materials) in order to fully secure safety. This preparation 
  work started at around 9:43am, Mar 12th and finished at 6:30pm, Mar 12th.
- Restoration work in reactor cooling function that was conducted to 
  achieve reactor cold shutdown has been completed and cooling of the 
  reactor has been commenced at 1:24 am, Mar 14th.
 
Unit 2 (shut down at 2:48pm on March 11th)
- Reactor is shut down and reactor water level is stable.
- Offsite power is available.
- Control rods are fully inserted (reactor is in subcritical status)
- Status of main steam isolation valve: closed
- Injection of water into the reactor is done by Make-up Water Condensate 
  System.
- We do not believe there is leakage of reactor coolant in the containment 
  vessel.
- At 5:32am, Mar 12th, the temperature of the suppression chamber exceeded 
  100 degrees. As the reactor pressure suppression function was lost, 
  at 5:32am, Mar 12th, it was determined that a specific incident 
  stipulated in article 15, clause 1 has occurred.
- We decided to prepare implementing measures to reduce the pressure of 
  the reactor containment vessel (partial discharge of air containing 
  radioactive materials) in order to fully secure safety. This preparation 
  work started at around 10:33am, Mar 12th and finished at 10:58pm, Mar 
  12th.
- Restoration work in reactor cooling function is in progress to achieve 
  reactor cold shutdown.
- Restoration work in reactor cooling function that was conducted to 
  achieve reactor cold shutdown has been completed and cooling of the 
  reactor has been commenced at 7:13 am, Mar 14th. 
 
Unit 3 (shut down at 2:48pm on March 11th)
- Reactor is shut down and reactor water level is stable.
- Offsite power is available.
- Control rods are fully inserted (reactor is in subcritical status)
- Status of main steam isolation valve: closed
- We do not believe there is leakage of reactor coolant in the containment 
  vessel.
- We decided to prepare implementing measures to reduce the pressure of 
  the reactor containment vessel (partial discharge of air containing 
  radioactive materials) in order to fully secure safety. The preparation 
  woke started at around 12:08pm, Mar 12th and finished at 12:13pm, Mar 
  12th.
- Reactor cold shutdown at 12:15pm, Mar 12th 
 
Unit 4 (shut down at 2:48pm on March 11th)
- Reactor is shut down and reactor water level is stable.
- Offsite power is available.
- At 0:43PM, there was a signal indicating that one of the control rods 
  may have not properly inserted. However, we confirmed that it was 
  inserted completely by another signal. We will inspect the reason of 
  this.
- Status of main steam isolation valve: closed
- Injection of water into the reactor is done by Make-up Water Condensate 
  System.
- We do not believe there is leakage of reactor coolant in the containment 
  vessel.
- In order to cool down the reactor, injection of water into the reactor 
  had been done by the Reactor Core Isolation Cooling System, however, 
  At 6:07am, Mar 12th, the temperature of the suppression chamber exceeded 
  100 degrees. As the reactor pressure suppression function was lost, at 
  6:07am, Mar 12th, it was determined that a specific incident stipulated 
  in article 15, clause 1 has occurred.
- We decided to prepare implementing measures to reduce the pressure of 
  the reactor containment vessel (partial discharge of air containing 
  radioactive materials) in order to fully secure safety. The preparation 
  woke started at around 11:44am, Mar 12th and finished at around 11:52am, 
  Mar 12th.
- Restoration work in reactor cooling function is in progress to achieve 
  reactor cold shutdown. 
 
Indication from monitoring posts installed at the site boundary did not 
show any difference from ordinary level.
No radiation impact to the external environment has been confirmed. We 
will continue to monitor in detail the possibility of radioactive material 
being discharged from exhaust stack or discharge canal. 
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