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 (May 14) 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
- Groundwater bypass (investigation holes a-c, pump wells 1-4)
- Observation holes on the sea side: (1)-(4)

Though the all β density in the leakage detection hole (southwest) of the underground reservoir No.3 yesterday (May 14) was about five times more compared to the previous results (May 13), the value is within the range of the past measurement results and an increase in density was not found in the drain hole (southwest) located on the outside of the leakage detection hole.

In other locations, no significant change was found with the results compared to the previous results (groundwater bypass (investigation holes a-c, pump wells 1-4): May 7, observation holes on the sea side (1)-(4): May 6, other locations: May 13).

The results of tritium sampling performed on May 6 and 7 (analysis performed once a week) are announced as follows.
- Groundwater bypass (investigation holes a-c, pump wells 1-4)
- Observation holes on the sea side (1)-(8)

Since the analysis method has been changed with lower detection limits for the purpose of further improving the detection accuracy, tritium was detected in 11 locations. The tritium detected in 9 (out of 11) locations was below the detection limit (approx. 2-3×10^-1 Bq/cm³) of the previous analysis (performed from April 29 to May 1). As the density is equivalent to the analysis results obtained in the groundwater bypass pump wells, etc. in the past, it is not considered to be a newly occurring increase in density. In other 2 locations, no significant change was found compared to the previous analysis.
Therefore, it is considered that there is no significant change with the tritium analysis results compared to the previous analysis results (April 29-May 1).

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

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