"While I was with Tokyo Electric Power Co. (Tepco), a question was raised internally as to whether or not the measuring pipe installed at the Fukushima No. 1 nuclear power plant, the diameter of which is about the same as that of a human thumb, can withstand an earthquake. But Tepco has yet to make clear whether or not the March 2011 earthquake damaged that pipe," says Toshio Kimura, a former Tepco plant engineer.

Kimura, 49, who served the company for 17 years from 1983 to 2000 and worked at Fukushima No. 1 for 12 years, is strongly of the view that pipes in the plant were damaged seriously by the quake before a subsequent tsunami struck the plant.

He thus casts doubt on Tepco's position that the tsunami caused loss of all the power sources, thus leading to the disaster. He says, "An effective means of determining the true cause of the accident would have been to analyze recorded data related to transient phenomena — data that show what happened near the reactor cores. Even though more than two years have passed since the disaster, however, Tepco has only released partial data.