Fukushima Daiichi NPS Prompt Report 2013

This is follow-up information regarding the water leak from the underground reservoirs at Fukushima Daiichi NPS.

The results of sampling performed on April 27 in the observation holes of the underground reservoirs are as follows.
- Drain holes of the underground reservoirs No.1-7
- Leakage detection holes of the underground reservoirs No.1-4 and 6

The all β in the drain hole (southwest) of the underground reservoir No.1 was found to have increased to approx. 10 times more compared to the day before yesterday^*.
* The result was compared with the day before yesterday (April 25) as the result on the previous day (April 26) was below the detection limit.

- Drain hole (southwest) of the underground reservoir No.1
[All β detected on April 25] 9.9×10^-2Bq/cm³
[All β detected on April 27] 1.1×10⁰Bq/cm³

The water samples obtained in the drain hole (southwest) of the underground reservoir No.1 in the afternoon yesterday (April 26) and today (April 27) are currently being analyzed. The results are to be announced.

As for the results obtained in the drain hole (northeast) and the leakage detection hole (northeast, southwest) of the underground reservoir No.1, no significant change was found compared to the previous day.

- Drain hole (northeast) of the underground reservoir No.1
[All β detected on April 26] 5.5×10¹Bq/cm³
[All β detected on April 27] 5.8×10¹Bq/cm³
- Leakage detection hole (northeast) of the underground reservoir No.1
[All β detected on April 26] 3.4×10⁴Bq/cm³
[All β detected on April 27] 3.4×10⁴Bq/cm³
- Leakage detection hole (southwest) of the underground reservoir No.1
[All β detected on April 26] 1.4×10^-1Bq/cm³
[All β detected on April 27] 1.4×10^-1Bq/cm³

The results of sampling performed in the drain holes of the underground reservoirs No.2-7 (12 locations) and the leakage detection holes of the underground reservoirs No.2-4 and 6 (sample could not be collected at 2 out of 8 locations) on April 27 are also announced. No significant change was found with the results compared to the previous day.

Please refer to our web page for the sampling results.
http://www.tepco.co.jp/en/nu/fukushima-np/f1/smp/2013/images/chosui_13042705-e.pdf

The water level, etc. of the underground reservoirs will continue to be intensively monitored.