Tokyo Electric Power Co. said Saturday that a cracked storage pit at the Fukushima No. 1 power plant was the source of a radioactive water leak contaminating the ocean and that it is attempting to fill it with concrete.
According to the utility and the Nuclear and Industrial Safety Agency, the square, concrete-covered pit is situated near an intake used to pump seawater into reactor No. 2.
Although the pit is small, it contains highly contaminated water with a radioactivity exceeding 1,000 millisieverts per hour that is leaking into the ocean from a 20-cm crack, Tepco said.