Fukushima Daiichi NPS Prompt Report 2013

This is follow-up information on influence of rainfall from the approaching typhoon on Fukushima Daiichi NPS.

Following overflow of accumulated water inside the dike in the B area (south side) for contaminated water storage tanks, we conducted all-β radioactivity analysis on the accumulated water inside the dike (by simplified measurement^*), and all-β was detected at 37Bq/L.

The all-β radioactivity analysis results on the respective tank areas (by simplified measurement) are as follows.

· H1 area: 200Bq/L
· H2 area (north): 140Bq/L
· H2 area (south): 3,700Bq/L
· H3 area: 4,600Bq/L
· H4 area (north): 170,000Bq/L
· H4 area (east): 2,400Bq/L
· H4 area: 110Bq/L
· H5 area: 430Bq/L
· H6 area: 160Bq/L
· H9 area: 9Bq/L
· H9 area (west): 8Bq/L
· B area (north): 23Bq/L
· B area (south): 37Bq/L
· C area (east): 2Bq/L
· C area (west): 8Bq/L
· E area: 6Bq/L
· G4 area (south): 3Bq/L
· G6 area (north): 8Bq/L
· G6 area (south): 34Bq/L

At around 3: 20 PM yesterday (on September 15), we started transferring the accumulated water inside the dike of the H4 area (north), which showed a high radioactivity level as a result of the all-β radioactivity analysis (by simplified measurement), to another tank in the same area using a temporary pump. We completed the transfer at around 11:20 PM on the same day.
We will sequentially transfer the accumulated water inside the dikes of the other areas to other tanks in the same area in order of their all-β radioactivity levels (the higher the level, the earlier) using a temporary pump.

* Simplified measurement: A total of 500ml of water is taken as a sample from 4 locations inside each dike. Using a GM survey meter, the density was measured from a filter paper moistened with the thus taken sample.

The sampling results on the respective tanks have been posted on our website. Please access the following page for the results:

Further, we conducted analysis on water at the south water outlet and in the drainage channels twice. Conditions at the first and second sampling at the south water outlet and in the drainage channels were as follows:
- The first sampling was conducted before the power station came under influence of rainfall from the approaching typhoon (sampling at the sampling points in the drainage channel B was conducted after the cleaning of the drainage channel B).
-The second sampling was conducted after the power station came under influence of rainfall from the approaching typhoon (after the sandbags at the drainage channel B were swept away).
We will continue monitoring.

[First sampling]
· Seawater near the south water outlet (the drainage channel exit) (T-2)
<Sampled at 10:33 AM on September 15>
Cesium-134: 3.4Bq/L
Cesium-137: 8.1Bq/L
All-β: ND (21Bq/L)

· Junction of the drainage channels B and C (C-1)
<Sampled at 11:35 AM on September 15>
Cesium-134: ND (18Bq/L)
Cesium-137: ND (26Bq/L)
All-β: 52Bq/L

· Point that showed a high dose equivalent rate on August 21 (B-1)
<Sampled at 11:55 AM on September 15>
Cesium-134: 41Bq/L
Cesium-137: 120Bq/L
All-β: 1,700Bq/L

· Downstream of B-1 (B-2)
Not sampled

· Point immediately short of the junction with the drainage channel C (B-3)
<Sampled at 11:50 AM on September 15>
Cesium-134: 300Bq/L
Cesium-137: 670Bq/L
All-β: 2,800Bq/L

· Point near Fureai Intersection in the drainage channel B (B-0-1)
<Sampled at 12:20 PM on September 15>
Cesium-134: 39Bq/L
Cesium-137: 90Bq/L
All-β: 280Bq/L

· Point near the main gate in the drainage channel C (C-0)
<Sampled at 12:10 PM on September 15>
Cesium-134: ND (19Bq/L)
Cesium-137: 33Bq/L
All-β: 69Bq/L

· Drainage channel C OP. 30m exit (C-2)
<Sampled at 10:50 AM on September 15>
Cesium-134: ND (18Bq/L)
Cesium-137: 31Bq/L
All-β: 71Bq/L

[Second sampling]
· Seawater near the south water outlet (the drainage channel exit) (T-2)
Not sampled

· Junction of the drainage channels B and C (C-1)
<Sampled at 3:48 PM on September 15 >
Cesium-134: 23Bq/L
Cesium-137: 60Bq/L
All-β: 250Bq/L

· Point that showed a high dose equivalent rate on August 21 (B-1)
Not sampled

· Downstream of B-1 (B-2)
Not sampled

· Point immediately short of the junction with the drainage channel C (B-3)
<Sampled at 3:42 PM on September 15>
Cesium-134: ND (20Bq/L)
Cesium-137: ND (27Bq/L)
All-β: 310Bq/L

· Point near Fureai Intersection in the drainage channel B (B-0-1)
<Sampled at 3:28 PM on September 15 >
Cesium-134: ND (19Bq/L)
Cesium-137: ND (26Bq/L)
All-β: 67Bq/L

· Point near the main gate in the drainage channel C (C-0)
<Sampled at 3:15 PM on September 15>
Cesium-134: ND (19Bq/L)
Cesium-137: 39Bq/L
All-β: 18Bq/L

· Drainage channel C OP. 30m exit (C-2)
<Sampled at 3:56 AM on September 15>
Cesium-134: ND (19Bq/L)
Cesium-137: ND (28Bq/L)
All-β: 280Bq/L

Here, ND indicates a case where the result was below the detection limit value, and the detection limit value is shown in parentheses.

For the sampling results, please refer to the following page on our website:

http://www.tepco.co.jp/en/nu/fukushima-np/f1/smp/index-e.html