Important Report from TEPCO

The Tokyo Electric Power Company, Incorporated, would like to make comments on subjects that are reported by the newspapers, TV or websites.

Damaged thermometer caused increase in temperature in the lower part of Reactor Pressure Vessel of Unit 2. Found out it remains cold shut down status.

February 16, 2012

At the beginning of February, it was found that one of the thermometers in the lower part of Reactor Pressure Vessel (RPV) indicated the temperature increase. TEPCO investigated both the possibilities; whether the temperature increased locally or the thermometer was damaged. We continuously monitor the situation while we increased the water injection up to double on step-by-step basis in order to prioritize the cooling of the Reactor.

We concluded from following two reasons that the increase in temperature was due to the damage of the thermometer and the lower part of the RPV is actually cooled adequately; all other thermometers in RPV and Primary Containment Vessel (PCV) indicated the temperature drop in line with increased the water injection, and higher resistance value than normal was measured when investigated the electric circuit.

It was also confirmed that Xenon concentration was below detection limit when gas sampling of PCV, which means th ere no re-criticality was happened. There is no difference of the concentration of the radioactive Cesium, compared with that measured before the temperature increase.

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