750 t of contaminated rainwater leaked to underground / “Bubble came up from the ground”

On 3/10/2015, Tepco announced approx. 750 t of highly contaminated rainwater leaked out of a dam and sank into the ground. The cause has not been identified.


It is a local “dam” to surround contaminated water tanks, which experienced the major leakage. The dam is designed to retain rainfall because rainwater becomes contaminated water soon as it falls on the ground.


In the morning of 3/10/2015, a Tepco employee found the water level decreased to half of last night. As a result of their investigation, water leakage was found near the bottom of an earth dike, and bubble was coming up from the joint part of a gutter and concrete base.

Tepco pumped up the retained water and transferred it to another dam. The estimated leaked volume was 747 m3.

The highest density of All β nuclides was 8,300,000 Bq/m3 in the retained rainwater.

In the first report of Tepco, they reported Strontium-90 density was over 100,000 Bq/m3, but they have not announce the exact reading since then.

Also, they reported the  leaked water was absorbed by the ground but did not flow to the sea for some reason.








Français :

750 T d’eau de pluie radioactive a fuit en sous-sol / “Des bulles ont jailli du sol”


Le 10 mars 2015, Tepco annonce qu’environ 750 tonne d’eau extrêmement radioactive se sont écoulées d’une retenue pour s’infiltrer dans le sol. La cause n’en est pas identifiée.

Il s’agit d’un “barrage” local qui entoure les citernes d’eau extrêmement radioactive, celles qui ont eu une fuite majeure. La retenue est conçue pour retenir les eaux de pluie parce qu’elles se contaminent dès qu’elles arrivent au sol.

Dans la matinée du 10 mars 2015, un employé de Tepco s’est aperçu que le niveau de l’eau était descendu de moitié pendant la nuit précédente. A la suite d’une inspection, ils ont trouvé la fuite au pied d’une digue de terre et des bulles se formaient à la jonction entre la base en béton et un caniveau.
Tepco a pompé les eaux encore retenues pour les transvaser dans une autre retenue. Le volume de la fuite est estimé à 747 m³.
Le record de radioactivité β dans les eaux de pluie retenues restantes est de 8 300 000 (8,3 millions de) Bq/m³.
Dans un premier compte-rendu, Tepco écrit que la radioactivité en strontium 90 dépasse 100 000 Bq/m³ mais depuis ils n’ont pas donné le chiffre exact relevé.
De plus, ils rapportent que la fuite a été absorbée par le sol et qu’elle n’est pas partie dans l’océan, sans autre précision.


About this site

This website updates the latest news about the Fukushima nuclear plant and also archives the past news from 2011. Because it's always updated and added live, articles, categories and the tags are not necessarily fitted in the latest format.
I am the writer of this website. About page remains in 2014. This is because my memory about 311 was clearer than now, 2023, and I think it can have a historical value. Now I'm living in Romania with 3 cats as an independent data scientist.
Actually, nothing has progressed in the plant since 2011. We still don't even know what is going on inside. They must keep cooling the crippled reactors by water, but additionally groundwater keeps flowing into the reactor buildings from the broken parts. This is why highly contaminated water is always produced more than it can circulate. Tepco is planning to officially discharge this water to the Pacific but Tritium is still remaining in it. They dilute this with seawater so that it is legally safe, but scientifically the same amount of radioactive tritium is contained. They say it is safe to discharge, but none of them have drunk it.


March 2015