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Press Release (Mar 12,2011)
Plant Status of Fukushima Daini Nuclear Power Station (as of 3PM arch 12th )
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, there was an alarm indicating that one of the control rods 
was not properly inserted, however, at 10:43am the alarm was automatically
called off. Other control rods have 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 had been done by the Reactor Core 
Isolation Cooling System, but at 3:48AM, injection by Make-up Water 
Condensate System begun.
- At 6:08PM, we announced the increase in reactor containment vessel 
pressure, assumed to be due to leakage of reactor coolant. However, we 
do not believe there is leakage of reactor coolant in the containment 
vessel at this moment.
- At 5:22AM, the temperature of the suppression chamber exceeded 100 
degrees. As the reactor pressure suppression function was lost, at 5:22AM,
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 commenced at around 9:43am.

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 had been done by the Reactor Core 
Isolation Cooling System, but at 4:50AM, injection by Make-up Water 
Condensate System begun.
- We do not believe there is leakage of reactor coolant in the containment
vessel.
- At 5:22AM, the temperature of the suppression chamber exceeded 100 
degrees. As the reactor pressure suppression function was lost, at 5:22AM,
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 commenced at around 10:33AM and completed at 10:58AM.

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
- Reactor Core Isolation Cooling System is turned off. Currently, 
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.
- 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 commenced at around 12:08PM and completed at 12:13AM.
- At 12:15PM, the reactor achieved cold shut down. 

Unit 4 (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
- Reactor Core Isolation Cooling System is turned off. Currently, 
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, the temperature of the suppression chamber exceeded 100 degrees. 
As the reactor pressure suppression function was lost, at 6:07AM, 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 commenced at around 11:44AM and completed at 11:52AM.

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.
There is no missing person within the power station.
We are presently checking on the site situation of each plant while 
keeping the situation of aftershock and Tsunami in mind.
A seriously injured worker is still trapped in the crane operating console
of the exhaust stack and his breathing and pulse cannot be confirmed. 
Currently, the rescue efforts are under way. 
A worker was lightly injured spraining his left ankle and cutting both 
knees when he fell while walking at the site. After medical treatment 
and subsequent rest, the worker has got back his workplace. 
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