Fukushima Daiichi wall seems effective as seawater pollution drops: TEPCO

Tokyo Electric Power Co. said on Nov. 5. that the concentration of radioactive substances in seawater near the shore of its crippled Fukushima Daiichi nuclear plant appears to be declining after the completion of a seaside underground wall there to block the flow of contaminated groundwater into the ocean. The seaside impermeable wall was completed on Oct. 26. “It is possible that we are starting to see positive results but, given the limited data, it is still too early to jump to a conclusion,” TEPCO said. “It would be necessary for us to continue observation over the course of several months.” The amount of radioactive substances that emit beta rays detected in the seawater dropped from 150 becquerels per liter in mid-September to 32 becquerels on Nov. 3, while cesium-137 was down from 16 becquerels to 10 becquerels. TEPCO said it also confirmed a rise in the underground water level on the landside of the revetment. The utility therefore believes it is likely that the new wall is successfully shielding the flow of contaminated groundwater, resulting in the decrease in radioactive substances flowing into the sea from the shore. (Translated by Kyodo News)