Bloomberg reports today: "One of the reactors in the crippled Fukushima nuclear plant may have been relying on flawed steel to hold the radiation in its core, according to an engineer who helped build its containment vessel four decades ago.
Mitsuhiko Tanaka says he helped conceal a manufacturing defect in the $250 million steel vessel installed at the Fukushima Dai-Ichi No. 4 reactor while working for a unit of Hitachi Ltd. (6501) in 1974. The reactor, which Tanaka has called a “time bomb,” was shut for maintenance when the March 11 earthquake triggered a 7-meter (23-foot) tsunami that disabled cooling systems at the plant, leading to explosions and radiation leaks."