Tepco started discharging the contaminated groundwater to the Pacific on 9/14/2015, Tepco reported.
It was discharged for nearly 6 hours in daytime. The reported volume of contaminated water was 838 tons.
The discharged water was pumped up from 20 of 41 wells called “sub-drain” situated beside crippled reactor buildings 1 ~ 4.
10,800,000 Bq/m3 of Cs-134/137 and 16,000,000 Bq/m3 of Tritium were measured from the water pumped this August. Tepco announced they purified water before discharging, however unremovable nuclide Tritium still remains in water. 390,000 ~ 600,000 Bq/m3 of Tritium was detected from “filtered” water from third party organization’s analysis.