Fukushima Daiichi NPS Prompt Report 2013

Yesterday (on October 22), at the contaminated water storage tanks in H9 west and H9 tank area, we started the water drain from the notch tank after analyzing the water inside the notch tank, and making sure the water met the emission standard.

The following rainfall caused the water level rise inside the dikes at H9 west and H9 tank areas, and further rainfall is anticipated, therefore, we opened the drain valve at these tank areas, and started to drain the water from inside to outside the dike.^*1
(*1Prior to the water drain, we conducted the water analysis sampled at the four corners inside the dike of each tank area, and made sure the water met the emission standard.)

The measurement results and the dike valve opening time at each tank area are as follows.

<H9 west tank area>
The drain valve was opened at 12:24 AM.
- Cesium-134: Below the detection limit value (the detection limit value: 13Bq/L)
- Cesium-137: Below the detection limit value (the detection limit value: 17Bq/L)
- Sr-90: Below the detection limit (the detection limit value: 2.3Bq/L)

<H9 tank area>
The drain valve was opened at 12:28 AM.
- Cesium-134: Below the detection limit value (the detection limit value: 13Bq/L)
- Cesium-137: Below the detection limit value (the detection limit value: 17Bq/L)
- Sr-90: Below the detection limit (the detection limit value: 2.3Bq/L)

*For the tank area map of Fukushima Daiichi NPS, please refer to the second page on the following URL.
http://www.tepco.co.jp/en/nu/fukushima-np/handouts/2013/images/handouts_131021_07-e.pdf

*Emission standard:
- Cesium-134: Below 15Bq/L
- Cesium-137: Below 25Bq/L
- No other γ detection (excluding natural nuclide)
- Sr-90: Below 10Bq/L (by simplified measurement method)
- Other nuclide meeting the notification level (referring to water quality inside the tank)