10 Décembre 2015
December 10, 2015
Dec. 10, 2015 - Updated 02:54 UTC+1
The operator of the Fukushima Daiichi nuclear power plant says levels of radioactivity in underground tunnels have sharply risen.
Tokyo Electric Power Company has detected 482,000 becquerels per liter of radioactive cesium in water samples taken from the tunnels on December 3rd. That's 4000 times higher than data taken in December last year.
The samples also contained 500,000 becquerels of a beta-ray-emitting substance, up 4,100 times from the same period.
Around 400 to 500 tons of radioactive water, including seawater washed ashore in the March 2011 tsunami, is still pooled in the tunnels.
The tunnels lie next to a structure used to temporarily store highly radioactive water, which cooled melted nuclear fuel inside the damaged reactors.
TEPCO officials say it is unlikely the wastewater stored in the building has seeped into the tunnels.
They say the water level in the tunnels is higher than that in the building and measures are in place to stop the toxic water from leaking out.
They plan to investigate what caused the spike in radiation.
They say there has been no leakage out of the tunnels as radiation levels in underground water nearby have not risen.