Fukushima Daiichi NPS Prompt Report 2013

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

Following the work progress updates such as the measures to prevent the expansion of contaminated water leakage from the underground reservoirs to the leakage detection holes announced yesterday (April 10), the following works have been performed today.

[Measures to prevent the expansion of contaminated water leakage from the underground reservoirs to the leakage detection holes]
- Underground reservoir No.1
The temporary pump was started in the morning to pump up the leaked water in the detection holes (northeast/southwest) and return it to the underground reservoir.
- Underground reservoir No.2
As the installation of a temporary pump was completed, the pump was started to pump up the leaked water in the detection holes (northeast/southwest) and return it to the underground reservoir.
- Underground reservoir No.3
The temporary pump is planned to be installed tomorrow. The work to return the leaked water in the detection hole (northeast/southwest) to the underground reservoir will be implemented tomorrow or on later date according to the progress of water transfer from the underground reservoir No.3 to No.6.

As for the underground reservoirs No.1 and No.2, the temporary pumps will be started in the morning and the afternoon tomorrow (once each) or on later date when the sampling of leaked water is performed to return the leaked water in the leakage detection holes (northeast/southwest) to the underground reservoirs.

[Visual inspection of the leakage detection hole (northeast) penetration of the underground reservoir No.2]
Continued from yesterday, the removal work of the impermeable sheet (rainwater protection sheet installed on the upper surface of the reservoir) covering the penetration and the gravels was carried out for visual inspection of the leakage detection hole (northeast) of the underground reservoir No.2. Once the removal of the impermeable sheet installed near the penetration is completed tomorrow, the visual inspection of the penetration will be performed. The results are to be announced.

[Boring investigation to confirm the contamination condition, etc. in the surrounding area of the underground reservoirs]
In order to confirm the contamination condition in the surrounding area of the underground reservoirs and the contamination expansion to the sea side, drilling work to install new observation holes (Holes used to sample water contained in the soil. New observation holes will be installed at 22 locations including 8 in the sea side) was carried out. The drilling work will be continued tomorrow. Water sampling from the observation holes and analysis will be started on April 15 (earliest). The analysis results are to be announced.