Top > Releases ･ Announcements > Fukushima Daiichi NPS Prompt Report > 2013 > Water Leak from the Underground Reservoirs in Fukushima Daiichi Nuclear Power Station (Follow-up Information No.47)
This is follow-up information regarding the water leak from the underground reservoirs at Fukushima Daiichi NPS.
The results of all β density analysis of the samples collected in the drain holes of the underground reservoirs No.1-7 (at 14 locations) and the leakage detection holes of the underground reservoirs No.1-4 and 6 (sampling could not be performed in 2 out of 10 locations) yesterday (April 12) morning are as follows.
Since the all β density in the drain hole (northeast) of the underground reservoir No.1 has increased during the period from April 10 to 12, it was judged that there may have been a small amount of water leakage from the sheet on the outside (bentonite sheet) to the outside.
Since there is no drainage in the surrounding area, there is no possibility that the leaked water has flowed out to the sea.
Though the incident has occurred in the controlled area, the condition has been judged to be subject to the application of Article 19-17, Item 10 of the Rule for the Installation, Operation, etc. of Commercial Nuclear Power Reactors (Rule for Commercial Nuclear Power Reactors) ("in the case that leakage of radioactive materials, etc. occurs in the controlled area due to a reactor facility failure or other unexpected incidents") at 11:28 AM on April 13. This incident is reported in accordance with Article 168 of the Technical specification for nuclear reactor facility at Fukushima Daiichi Nuclear Power Station (Report).
Please refer to the document on iodine and cesium radioactivity analysis results available in our web page.
URL: http://www.tepco.co.jp/en/nu/fukushima-np/f1/smp/index-e.html
- Drain hole (northeast) of the underground reservoir No.1
Sampling performed at 5:10 AM on April 12
Chloride concentration: 14ppm (Previously announced)
Iodine 131: Below the detection limit (Detection limit: 2.7×10-2Bq/cm3)
Cesium 134: Below the detection limit (Detection limit: 5.3×10-2Bq/cm3)
Cesium 137: Below the detection limit (Detection limit: 6.5×10-2Bq/cm3)
All β: 1.5×100Bq/cm3
- Drain hole (southwest) of the underground reservoir No.1
Sampling performed at 5:10 AM on April 12
Chloride concentration: 7ppm (Previously announced)
Iodine 131: Below the detection limit (Detection limit: 3.2×10-2Bq/cm3)
Cesium 134: Below the detection limit (Detection limit: 4.8×10-2Bq/cm3)
Cesium 137: Below the detection limit (Detection limit: 7.2×10-2Bq/cm3)
All β: 3.5×10-2Bq/cm3
- Drain hole (northeast) of the underground reservoir No.2
Sampling performed at 5:20 AM on April 12
Chloride concentration: 12ppm (Previously announced)
Iodine 131: Below the detection limit (Detection limit: 2.6×10-2Bq/cm3)
Cesium 134: Below the detection limit (Detection limit: 5.4×10-2Bq/cm3)
Cesium 137: Below the detection limit (Detection limit: 6.6×10-2Bq/cm3)
All β: 4.5×101Bq/cm3
- Drain hole (southwest) of the underground reservoir No.2
Sampling performed at 5:20 AM on April 12
Chloride concentration: 8ppm (Previously announced)
Iodine 131: Below the detection limit (Detection limit: 3.1×10-2Bq/cm3)
Cesium 134: Below the detection limit (Detection limit: 5.3×10-2Bq/cm3)
Cesium 137: Below the detection limit (Detection limit: 6.9×10-2Bq/cm3)
All β: 3.1×10-1Bq/cm3)
- Drain hole (northeast) of the underground reservoir No.3
Sampling performed at 5:30 AM on April 12
Chloride concentration: 7ppm (Previously announced)
Iodine 131: Below the detection limit (Detection limit: 2.4×10-2Bq/cm3)
Cesium 134: Below the detection limit (Detection limit: 4.9×10-2Bq/cm3)
Cesium 137: Below the detection limit (Detection limit: 6.6×10-2Bq/cm3)
All β: 1.6×10-1Bq/cm3
- Drain hole (southwest) of the underground reservoir No.3
Sampling performed at 5:30 AM on April 12
Chloride concentration: 6ppm (Previously announced)
Iodine 131: Below the detection limit (Detection limit: 3.4×10-2Bq/cm3)
Cesium 134: Below the detection limit (Detection limit: 5.2×10-2Bq/cm3)
Cesium 137: Below the detection limit (Detection limit: 6.8×10-2Bq/cm3)
All β: 6.7×10-1Bq/cm3
- Drain hole (northeast) of the underground reservoir No.4
Sampling performed at 5:50 AM on April 12
Chloride concentration: 10ppm (Previously announced)
Iodine 131: Below the detection limit (Detection limit: 2.8×10-2Bq/cm3)
Cesium 134: Below the detection limit (Detection limit: 4.9×10-2Bq/cm3)
Cesium 137: Below the detection limit (Detection limit: 6.8×10-2Bq/cm3)
All β: 1.3×10-1Bq/cm3
- Drain hole (southwest) of the underground reservoir No.4
Sampling performed at 5:50 AM on April 12
Chloride concentration: 8ppm (Previously announced)
Iodine 131: Below the detection limit (Detection limit: 2.7×10-2Bq/cm3)
Cesium 134: Below the detection limit (Detection limit: 5.7×10-2Bq/cm3)
Cesium 137: Below the detection limit (Detection limit: 6.8×10-2Bq/cm3)
All β: 7.5×10-2Bq/cm3
- Drain hole (northeast) of the underground reservoir No.5
Sampling performed at 6:30 AM on April 12
Chloride concentration: 8ppm (Previously announced)
Iodine 131: Below the detection limit (Detection limit: 2.4×10-2Bq/cm3)
Cesium 134: Below the detection limit (Detection limit: 4.8×10-2Bq/cm3)
Cesium 137: Below the detection limit (Detection limit: 6.6×10-2Bq/cm3)
All β: 8.8×10-1Bq/cm3
- Drain hole (southwest) of the underground reservoir No.5
Sampling performed at 6:30 AM on April 12
Chloride concentration: 9ppm (Previously announced)
Iodine 131: Below the detection limit (Detection limit: 2.8×10-2Bq/cm3)
Cesium 134: Below the detection limit (Detection limit: 5.3×10-2Bq/cm3)
Cesium 137: Below the detection limit (Detection limit: 6.9×10-2Bq/cm3)
All β: 6.2×10-2Bq/cm3
- Drain hole (northeast) of the underground reservoir No.6
Sampling performed at 6:20 AM on April 12
Chloride concentration: 13ppm (Previously announced)
Iodine 131: Below the detection limit (Detection limit: 2.8×10-2Bq/cm3)
Cesium 134: Below the detection limit (Detection limit: 5.0×10-2Bq/cm3)
Cesium 137: Below the detection limit (Detection limit: 6.5×10-2Bq/cm3)
All β: 3.1×10-2Bq/cm3
- Drain hole (southwest) of the underground reservoir No.6
Sampling performed at 6:20 AM on April 12
Chloride concentration: 8ppm (Previously announced)
Iodine 131: Below the detection limit (Detection limit: 3.0×10-2Bq/cm3)
Cesium 134: Below the detection limit (Detection limit: 5.8×10-2Bq/cm3)
Cesium 137: Below the detection limit (Detection limit: 7.0×10-2Bq/cm3)
All β: 5.0×10-2Bq/cm3
- Drain hole (northeast) of the underground reservoir No.7
Sampling performed at 6:10 AM on April 12
Chloride concentration: 7ppm (Previously announced)
Iodine 131: Below the detection limit (Detection limit: 2.7×10-2Bq/cm3)
Cesium 134: Below the detection limit (Detection limit: 5.2×10-2Bq/cm3)
Cesium 137: Below the detection limit (Detection limit: 6.5×10-2Bq/cm3)
All β: 4.5×10-2Bq/cm3
- Drain hole (southwest) of the underground reservoir No.7
Sampling performed at 6:10 AM on April 12
Chloride concentration: 9ppm (Previously announced)
Iodine 131: Below the detection limit (Detection limit: 2.3×10-2Bq/cm3)
Cesium 134: Below the detection limit (Detection limit: 4.8×10-2Bq/cm3)
Cesium 137: Below the detection limit (Detection limit: 6.5×10-2Bq/cm3)
All β: 9.5×10-2Bq/cm3
- Leakage detection hole (northeast) of the underground reservoir No.1
Sampling performed at 9:00 AM on April 12
Chloride concentration: 1100ppm (Previously announced)
Iodine 131: Below the detection limit (Detection limit: 1.9×10-1Bq/cm3)
Cesium 134: Below the detection limit (Detection limit: 2.4×10-1Bq/cm3)
Cesium 137: Below the detection limit (Detection limit: 1.1×10-1Bq/cm3)
All β: 3.2×104Bq/cm3
- Leakage detection hole (southwest) of the underground reservoir No.1
Sampling performed at 9:20 AM on April 12
Chloride concentration: 7ppm (Previously announced)
Iodine 131: Below the detection limit (Detection limit: 2.8×10-2Bq/cm3)
Cesium 134: Below the detection limit (Detection limit: 5.0×10-2Bq/cm3)
Cesium 137: Below the detection limit (Detection limit: 6.6×10-2Bq/cm3)
All β: 1.2×10-1Bq/cm3
- Leakage detection hole (northeast) of the underground reservoir No.2
Sampling performed at 10:40 AM on April 12
Chloride concentration: 250ppm (Previously announced)
Iodine 131: Below the detection limit (Detection limit: 6.7×10-2Bq/cm3)
Cesium 134: Below the detection limit (Detection limit: 6.3×10-2Bq/cm3)
Cesium 137: 1.1×10-1Bq/cm3
All β: 6.7×103Bq/cm3
- Leakage detection hole (southwest) of the underground reservoir No.2
Sampling performed at 9:40 AM on April 12
Chloride concentration: 10ppm (Previously announced)
Iodine 131: Below the detection limit (Detection limit: 2.8×10-2Bq/cm3)
Cesium 134: Below the detection limit (Detection limit: 5.0×10-2Bq/cm3)
Cesium 137: Below the detection limit (Detection limit: 6.5×10-2Bq/cm3)
All β: 2.7×100Bq/cm3
- Leakage detection hole (northeast) of the underground reservoir No.3
Sampling performed at 10:30 AM on April 12
Chloride concentration: 8ppm (Previously announced)
Iodine 131: Below the detection limit (Detection limit: 2.7×10-2Bq/cm3)
Cesium 134: Below the detection limit (Detection limit: 5.1×10-2Bq/cm3)
Cesium 137: Below the detection limit (Detection limit: 6.9×10-2Bq/cm3)
All β: 1.6×10-2Bq/cm3
- Leakage detection hole (southwest) of the underground reservoir No.3
Sampling performed at 10:05 AM on April 12
Chloride concentration: 270ppm (Previously announced)
Iodine 131: Below the detection limit (Detection limit: 5.8×10-2Bq/cm3)
Cesium 134: Below the detection limit (Detection limit: 6.4×10-2Bq/cm3)
Cesium 137: Below the detection limit (Detection limit: 7.5×10-2Bq/cm3)
All β: 2.0×103Bq/cm3
- Leakage detection hole (northeast) of the underground reservoir No.4
Sampling performed at 11:10 AM on April 12
Chloride concentration: 9ppm (Previously announced)
Iodine 131: Below the detection limit (Detection limit: 2.2×10-2Bq/cm3)
Cesium 134: Below the detection limit (Detection limit: 4.9×10-2Bq/cm3)
Cesium 137: Below the detection limit (Detection limit: 6.7×10-2Bq/cm3)
All β: Below the detection limit (Detection limit: 1.4×10-2Bq/cm3)
- 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 11:15 AM on April 12
Chloride concentration: 6ppm (Previously announced)
Iodine 131: Below the detection limit (Detection limit: 2.8×10-2Bq/cm3)
Cesium 134: Below the detection limit (Detection limit: 5.1×10-2Bq/cm3)
Cesium 137: Below the detection limit (Detection limit: 6.8×10-2Bq/cm3)
All β: 2.1×10-2Bq/cm3
- 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 of concern will continue to be intensively monitored.
© Tokyo Electric Power Company Holdings, Inc.
