Fukushima Daiichi NPS Prompt Report 2013

This is follow-up information on the "water leak at a tank in the H4 area in Fukushima Daiichi Nuclear Power Station" found on August 19.

In connection with the water leaking from the drain valve at the H4 area tank dike, we conducted analysis on water in the groundwater bypass pump wells No.7-No.10 (4 locations) yesterday (on August 29), and we would like to announce the results.

<Pump well No.7>
(Sampling on August 29)
Tritium : 470Bq/L
All β :Below the detection limit value (16Bq/L)

<Pump well No.8>
(Sampling on August 29)
Tritium : 56Bq/L
All β : Below the detection limit value (16Bq/L)

<Pump well No.9>
(Sampling on August 29)
Tritium : 38Bq/L
All β : Below the detection limit value (16Bq/L)

<Pump well No.10>
(Sampling on August 29)
Tritium : 290Bq/L
All β : Below the detection limit value (16Bq/L)

* In a case where the result is below the detection limit value, the detection limit value is shown in the parentheses.

The tritium densities in the groundwater bypass pump wells No.1-No.12 measured from December 2012 to March 2013 in preparation for bringing the groundwater bypass into operation were 9 to 450Bq/L. Additionally, the results obtained this time are sufficiently low compared to the density limit by the announcement of Reactor Regulation (60,000Bq/L).