10 Valves That Workers Were Supposed to Close Were Open at Fukushima No. 1 Nuclear Plant, Believed to be Cause of Radioactive Water Leak

Yomiuri Shimbun file photo
Tokyo Electric Power Company Holdings Inc. headquarters in Chiyoda Ward, Tokyo

Ten manual valves that workers were supposed to close were open on an equipment at the Fukushima No. 1 nuclear power plant when contaminated water leaked from a pipe at the plant, Tokyo Electric Power Company Holdings, Inc. said Thursday.

About 5.5 tons of contaminated water containing radioactive materials mixed with cleaning water leaked Wednesday when workers were cleaning the equipment. The water is believed to have leaked from the open valves.

No leakage into the sea has been detected, nor any increase in radiation out side the plant, according to the company.