Fukushima Daiichi NPS Prompt Report 2013

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

The samples obtained in the observation holes of the underground reservoirs on April 26 have been reanalyzed. The results are as follows.

The analysis results announced at 2:25 AM today (April 27) indicated that all β with density slightly above the detection limit (2.8x10^-2Bq/cm³) was detected in 13 out of 22 observation holes of the underground reservoirs (Max: 4.8×10^-2Bq/cm³). However, the reanalysis results indicate that all β with density slightly above the detection limit (3.0x10^-2Bq/cm³) was detected in 2 out of 22 observation holes of the underground reservoirs (Max: 3.7×10^-2Bq/cm³).

The all β densities detected in the reanalysis were equivalent to those announced previously. The reason why the all β detected in the previous analysis was not detected this time is considered to be due to the fluctuation within the range of detection limit.

The results of sampling performed in the drain holes and the leakage detection holes of the underground reservoirs yesterday (April 26) are also announced.
- Drain holes of the underground reservoirs No.1-7
- Leakage detection holes of the underground reservoirs No.1-4 and 6

No significant change was found with the analysis results obtained yesterday (April 26) compared to the day before yesterday (April 25).

Please visit our web page for the sampling results (obtained on April 26, 2013 [2]).
http://www.tepco.co.jp/en/nu/fukushima-np/f1/smp/2013/images/chosui_13042702-e.pdf

Analysis results of the samples obtained in the underground reservoirs (obtained on April 26)
http://www.tepco.co.jp/en/nu/fukushima-np/f1/smp/2013/images/chosui_13042703-e.pdf

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