Fukushima nuclear plant: Toxic isotope found in groundwater

"Tokyo Electric Power Company (Tepco) said tests showed Strontium-90 was present at 30 times the legal rate"

BBC report

Although I am slightly confused as further down the report claims that the groundwater is being contained by concrete foundations. Now from what I know of the plans and elevations of the site, if its contained in foundations then it sure as hell isn't groundwater.

Surely groundwater implies that the leak is through the concrete and actually into the ground, and hence on its way downwards to the water table?

Originally posted by UltraMind
Although I am slightly confused as further down the report claims that the groundwater is being contained by concrete foundations. Now from what I know of the plans and elevations of the site, if its contained in foundations then it sure as hell isn't groundwater.

I wouldn't call it groundwater either, so maybe it's a translation issue or something? The water is pretty far underground but if it's inside the structure I wouldn't call it groundwater. I suspect it's below the torus but above the bottom floor of the secondary containment structure in the left view of this diagram:



In addition, they probably also have some contamination of the real groundwater from leaking storage tanks outside the structure, though I suspect the radiation levels are probably a lot worse inside.