Nuclear Experts: Portion of Fukushima’s molten fuel believed to have “moved into earth”
TEPCO officials estimate that approximately 300 tons of toxic water is rushing into the Pacific Ocean daily, enough to fill an Olympic-sized swimming pool every eight days.
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Although no one can confirm where the melted fuel cores are located, some experts believe some of the radioactive material from the damaged core has moved into the earth. The recent spike in radiation levels in the water may therefore be coming from groundwater coming into contact with the melted cores.
Earlier this month, TEPCO said that radiation levels in its groundwater observation hole located on the east side of the complex had reached 310 becquerels per litre for cesium-134 and 650 becquerels per litre for cesium-137.
According to the World Health Organization, drinking water at 300 becquerels per litre would be approximately equal to one year's exposure to natural background radiation, or 10 to 15 chest X-rays.
http://www.ctvnews.ca/sci-tech/japan-s-fukushima-nuclear-plant-leaks-what-you-need-to-know-1.1423249