The concentration of radioactive materials in water in an underground duct at the Fukushima No. 1 nuclear plant soared 4,000 times from a year ago, Tokyo Electric Power Co. said.
The concentration of radioactive materials in water in an underground duct at the Fukushima No. 1 nuclear plant soared 4,000 times from a year ago, Tokyo Electric Power Co. said.
TEPCO, operator of the crippled plant, said Dec. 9 that highly contaminated water stored at a nearby building may have leaked into the duct.
The utility said it found no increases in radioactivity levels in underground water in other areas, indicating the leak was limited to the duct.
According to TEPCO, about 420 tons of contaminated water amassed in the duct after the tsunami generated by the 2011 Great East Japan Earthquake inundated the plant with seawater.
A survey conducted on Dec. 11, 2014, found 94 becquerels of radioactive cesium-137 per liter in the underground duct. However, a survey on Dec. 3 this year found 390,000 becquerels per liter.
The cesium-137 reading in the contaminated water stored in the nearby building was 19 million becquerels per liter in a Nov. 3 survey.
TEPCO said it is considering pumping out the radioactive water in the duct and filling it with concrete.