On October 15, 2012, a worker of a cooperative company found a water leakage in a corridor in the back of the large equipment hatch on the first floor of Unit 3 Turbine Building at Fukushima Daiichi Nuclear Power Station. At around 10:10 AM on the same day, a TEPCO employee confirmed the leakage. As we stopped the pump transferring the accumulated water from Unit 3 Turbine Building basement to the Central Radioactive Waste Treatment Facility (Miscellaneous Solid Waste Volume Reduction Treatment Building [High Temperature Incinerator Building]) at 10:18 AM, the leakage was stopped at 11:16 AM. The leaked water remained on the floor on the downside of the slope in the back of the large equipment hatch and there was no leakage to the outside of the building.
The area affected by the leakage was approx. 3m x approx. 6m and approx. 5mm in depth, and the leakage amount was estimated to be approx. 90L. As a result of nuclide analysis of the leaked water, cesium 134 density was approx. 1.0 x 10⁴ Bq/cm³ and cesium 137 density was approx. 1.8 x 10⁴ Bq/cm³. The leaked water was identified to be the accumulated water of the Turbine Building.

On October 17, we received a directive document* "Radioactive Water Leakage in Unit 3 Turbine Building at TEPCO Fukushima Daiichi Nuclear Power Station (Direction)" from the Nuclear Regulation Authority.

(Previously announced on October 18, 2012)

In accordance with the direction given, we have put together a report attached addressing the measures against radioactive water leakage in the Turbine Building and submitted it to the Nuclear Regulation Authority today.

Attachment
"Measures against Radioactive Water Leakage in Unit 3 Turbine Building at Fukushima Daiichi Nuclear Power Station" (PDF 1.37MB)