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 in the underground reservoirs yesterday (April 30) are as follows.
- Drain holes of the underground reservoirs No.1-7
- Leakage detection holes of the underground reservoirs No.1-4 and 6
- Observation holes of the underground reservoirs (around reservoirs No.1-3): A1-A19
- Observation holes of the underground reservoirs (around reservoir No.6): B1-B3
- Observation holes on the sea side (1)-(6)
- Groundwater bypass investigation holes a-c
- Groundwater bypass pump wells 1-4
- Observation holes on the sea side (8)

The all β and γdensities were confirmed to have decreased in the leakage detection hole (northeast) of the underground reservoir No.1.

Other than the above, no significant change was found in the drain holes of the underground reservoirs No.1-7, the leakage detection holes of the underground reservoirs No.1-4 and 6, the observation holes of the underground reservoirs (around the underground reservoirs No.1-3 and 6) and the groundwater bypass (investigation holes and pump wells) compared to the previous analysis results.

As for the observation hole on the sea side (8), a newly added sampling location, the chloride concentration was 8ppm and the all β was below the detection limit.

Please visit our web page for the sampling results.
http://www.tepco.co.jp/en/nu/fukushima-np/f1/smp/2013/images/chosui_13050101-e.pdf

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