A report on the Fukushima disaster released this year has yet to shed light on the ‘bigger picture’ behind the meltdown as lead investigators gathered at a forum of the Science Council of Japan for a private panel discussed the necessity of a ‘root-and-branch’ probe into last year’s incident, Asahi Shimbun reports.

Yoichiro Hatamura, Professor emeritus of engineering at the University of Tokyo, who chaired the government inquiry, said that investigations should look into the mistakes made after Tepco engineers failed to notice that water-level gauges were malfunctioning early in the crisis.

Kiyoshi Kurokawa, former chairman of the Science Council of Japan and leader of a Diet investigative committee, said that Japan’s nuclear engineers should improve their expertise and skill by frequent exchanges with foreign counterparts.

Former chairman of the Japan Science and Technology Agency Koichi Kitazawa said, “It would still be an enormous challenge to bring an accident under control if another occurred,” citing the difficulty of gathering evidence from the destroyed reactor buildings after probes turned up insufficient answers.