Fukushima Daiichi NPS Prompt Report 2013

This is follow-up information regarding the water leak from the underground reservoirs at Fukushima Daiichi NPS.

The sampling result of all β detected in the drain hole (southwest) of the underground reservoir No.1 in the morning today (April 28) is announced. The density has decreased compared to April 27 and is equivalent to that on April 26.

- Drain hole (southwest) of the underground reservoir No.1
[All β detected in the morning on April 28] 7.4×10^-2Bq/cm³
[All β detected in the afternoon on April 27] 1.1×10⁰Bq/cm³ (Previously announced)
[All β detected in the morning on April 27] 1.1×10⁰Bq/cm³ (Previously announced)
[All β detected in the afternoon on April 26] 4.1×10^-2Bq/cm³ (Previously announced)
[All β detected in the morning on April 26] Below the detection limit (2.6×10^-2Bq/cm³) (Previously announced)

As for the all β in the drain hole (southwest) of the underground reservoir No.1, sampling and analysis are to be performed again this afternoon. The cause of the increase in all β yesterday (April 27) will continue to be investigated and monitoring will be continued.

The results of chloride concentration analysis performed in the drain holes of the underground reservoirs No.1-7 (14 locations) and the leakage detection holes of the underground reservoirs No.1-4 and 6 (sample could not be collected at 2 out of 10 locations) are as follows.

No significant change was found compared to the previous results.

[Chloride concentration analysis results on April 28]

- Drain hole (northeast) of the underground reservoir No.1
Sampling performed at 5:15 AM on April 28
Chloride concentration: 17ppm

- Drain hole (southwest) of the underground reservoir No.1
Sampling performed at 5:05 AM on April 28
Chloride concentration: 6ppm

- Drain hole (northeast) of the underground reservoir No.2
Sampling performed at 5:15 AM on April 28
Chloride concentration: 10ppm

- Drain hole (southwest) of the underground reservoir No.2
Sampling performed at 5:10 AM on April 28
Chloride concentration: 7ppm

- Drain hole (northeast) of the underground reservoir No.3
Sampling performed at 5:25 AM on April 28
Chloride concentration: 7ppm

- Drain hole (southwest) of the underground reservoir No.3
Sampling performed at 5:20 AM on April 28
Chloride concentration: 4ppm

- Drain hole (northeast) of the underground reservoir No.4
Sampling performed at 5:30 AM on April 28
Chloride concentration: 10ppm

- Drain hole (southwest) of the underground reservoir No.4
Sampling performed at 5:35 AM on April 28
Chloride concentration: 9ppm

- Drain hole (northeast) of the underground reservoir No.5
Sampling performed at 5:40 AM on April 28
Chloride concentration: 11ppm

- Drain hole (southwest) of the underground reservoir No.5
Sampling performed at 5:45 AM on April 28
Chloride concentration: 6ppm

- Drain hole (northeast) of the underground reservoir No.6
Sampling performed at 5:55 AM on April 28
Chloride concentration: 10ppm

- Drain hole (southwest) of the underground reservoir No.6
Sampling performed at 5:50 AM on April 28
Chloride concentration: 8ppm

- Drain hole (northeast) of the underground reservoir No.7
Sampling performed at 6:00 AM on April 28
Chloride concentration: 5ppm

- Drain hole (southwest) of the underground reservoir No.7
Sampling performed at 6:05 AM on April 28
Chloride concentration: 6ppm

- Leakage detection hole (northeast) of the underground reservoir No.1
Sampling performed at 8:00 AM on April 28
Chloride concentration: 1200ppm

- Leakage detection hole (southwest) of the underground reservoir No.1
Sampling performed at 8:05 AM on April 28
Chloride concentration: 6ppm

- Leakage detection hole (northeast) of the underground reservoir No.2
Sampling performed at 8:10 AM on April 28
Chloride concentration: 11ppm

- Leakage detection hole (southwest) of the underground reservoir No.2
Sampling performed at 8:15 AM on April 28
Chloride concentration: 11ppm

- Leakage detection hole (northeast) of the underground reservoir No.3
Sampling performed at 8:20 AM on April 28
Chloride concentration: 9ppm

- Leakage detection hole (southwest) of the underground reservoir No.3
Sampling performed at 8:25 AM on April 28
Chloride concentration: 15ppm

- Leakage detection hole (northeast) of the underground reservoir No.4
Sampling performed at 8:35 AM on April 28
Chloride concentration: 8ppm

- Leakage detection hole (southwest) of the underground reservoir No.4
*Sampling was not performed since the amount of sample necessary for analysis could not be obtained.

- Leakage detection hole (northeast) of the underground reservoir No.6
Sampling performed at 8:55 AM on April 28
Chloride concentration: 7ppm

- Leakage detection hole (southwest) of the underground reservoir No.6
*Sampling was not performed since the amount of sample necessary for analysis could not be obtained.

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