It has surfaced that Tokyo Electric Power Co. provided misleading information to the Diet investigation committee tasked to determine the causes of the March 11, 2011, nuclear catastrophe at Tepco's Fukushima No. 1 nuclear power plant, thus preventing the examination of critical components of the No. 1 reactor, one of three Fukushima reactors that suffered meltdowns.

It is impossible to believe Tepco's explanation that it had no intention of obstructing the committee's work. The Diet should restart its investigation and Tepco should fully cooperate.

The committee had learned from eyewitness accounts by subcontract workers that, shortly before the reactor was hit by the March 11, 2011, tsunami, water was leaking on the fourth floor, where two isolation condensers (ICs) are located, of the building housing the No. 1 reactor. Isolation condensers turn steam vapor into water without using electricity and inject water into reactors to cool them by utilizing gravity in emergencies. The ICs in question stopped functioning shortly after the plant was hit by the 3/11 earthquake.