At 2:48PM on March 11th, the reactor of Fukushima Daini Nuclear Power
Station Unit 1 (Boiling Water Reactor, rated output 1,100 Megawatts) shut
down due to the impact of the earthquake.
Reactor Core Isolation Cooling System was used to inject water into the
reactor to cool it. Today at 4:50AM, water injection by Make-up Water
Condensate System begun.
Subsequently, at 5:32AM, the temperature of the suppression chamber
exceeded 100 degrees.
As the reactor pressure suppression function was lost, at 5:32AM, it was
determined that a specific incident stipulated in article 15, clause 1 has
Safety and Impact to the Environment
- Currently, water level to cool irradiated fuels in the reactor is
- Indication of monitoring posts installed in the site boundary is not
different from normal. Currently, no radiation impact to the external
environment has been confirmed.
We will continue monitoring in detail discharge of radioactive material
from exhaust stack and discharge canal.