Fukushima Daiichi NPS Prompt Report 2013

We conducted a purification test of wells (sub-drain pits) located next to the Units 1-4 buildings at Fukushima Daiichi NPS, and detected radioactive materials in water accumulated in the pits. One possible cause of the entrance of radioactive materials there is fallout. We are installing new observation wells around the Units 1-4 buildings to find out the influence of fallout.

Yesterday (on September 11), we sampled water in the newly installed sub-drain observation well (1T-4) at the sea-facing side of Unit 1 Turbine Building, and the newly installed sub-drain observation wells (2T-1 and 2T-2) at the sea-facing side of 1-R of Unit 2 Turbine Building. We would like to announce measurement results for radioactive materials such as cesium and all β as we obtained the results today (on September 12).

<Sub-drain observation well 1T-4 (at the sea-facing side of Unit 1 Turbine Building)>
- Sampled on September 11
Cesium-134: ND (0.46Bq/L)
Cesium-137: 0.88Bq/L
All-β: 9500Bq/L

<Sub-drain observation well 2T-1 (at the sea-facing side of Unit 2 Turbine Building)>
- Sampled on September 11
Cesium-134: ND (0.36Bq/L)
Cesium-137: 0.66Bq/L
All-β: ND (24Bq/L)

<Sub-drain observation well 2T-2 (at the sea-facing side of Unit 2 Turbine Building)>
- Sampled on September 11
Cesium-134: ND (0.47Bq/L)
Cesium-137: ND (0.60Bq/L)
All-β: 830Bq/L

* ND indicates a case where the result is below the detection limit value. The detection limit value is shown in parentheses.

The tritium density in water in the sub-drain observation well 4T-1 at the sea-facing side of Unit 4 Turbine Building, sampled on September 9, was 1800Bq/L.

<Sub-drain observation well 4T-1 (at the sea-facing and south side of Unit 4 Turbine Building)>
- Sampled on September 9
Tritium: 1800Bq/L
Cesium-134: ND (0.38Bq/L) (previously announced)
Cesium-137: ND (0.44Bq/L) (previously announced)
All-β: ND (17Bq/L) (previously announced)

* ND indicates a case where the result is below the detection limit value. The detection limit value is shown in parentheses.

For the past sampling results, please refer to the following page on our website:
http://www.tepco.co.jp/en/nu/fukushima-np/f1/smp/index-e.html