"Labeling tags were not attached to 1,500 valves controlling the flow of radioactive water in piping and other equipment at the Fukushima No. 1 nuclear power plant in the aftermath of the March 2011 disaster, sources said.
The revelation shows that plant operator Tokyo Electric Power Co.'s measures to deal with the accident are still lagging three years after the triple meltdown triggered by the Great East Japan Earthquake and tsunami.
Tags are used to indicate where pipes and other equipment are connected to prevent workers from operating the wrong valves and releasing radioactive water to the wrong places. The pipes connect contaminated water storage tanks, pumps and other equipment."