A Wall Street Journal report -after interviews with former TEPCO engineers and executives- throws more light on the failure of power and cooling at certain reactors in Fukushima Daiichi that led to the nuclear meltdown. The difference not grasped at the time turned out to be the critical difference between the reactors where electricity to cool the reactors worked and where the the electricity failed. Of the 10 nuclear reactors at Fukushima, only the 4 with the earlier Mark 1 design failed. These reactors were the earliest reactors installed by G.E. beginning in the 1970's. The Mark 1 reactors were serviced by an American engineering firm called Ebasco. Ebasco designed the reactor buildings really small so that they would be compact and economical. Because of the small size of the reactor buildings the generators providing the electricity supplies to the Mark 1 reactors could not be installed inside the reactor buildings made of fortified concrete and were installed in buildings outside lacking similiar protection. These outhoused generator buildings could not withstand the tsunami, resulting in the loss of power and cooling for these reactors, and leading eventually to the meltdown. The reactors with the Mark II and later designs were installed along with the generators in the same fortified concrete buildings, and these survived the tsunami without disruption in power supplies and cooling. This critical difference was noted by older TEPCO executives who were intervewed, but nothing was done about this because of the added cost of making the major modifications that would be needed. The regulatory system also failed to catch the problems with the original blueprints and design for housing the reactors and generators for cooling reactors. In 2001 the original 30 year operating permit for the Fukushima Daiichi nuclear reactor was renewed, and again in 2011 for another ten year period. Japan's Nuclear and Industrial Safety Agency is part of the industry ministry, and not kept separate and independent from the nuclear industry, a structural flaw. The ministry considered its job to be promoting nuclear power, and increasing nuclear power from 30% in 2010 to 50% of Japan's electricity output. One inspection official says fundamental design and construction of the reactors from a 30-40 year old design were never looked at in safety reviews by regulators approving the extensions. He even goes to the point of saying that the reviews focussed on things like pipes and fittings, missing entirely the safety of the outhouse buildings housing the generators. One of the top TEPCO engineers says this difference stood out like a sore thumb when did a walk through during inspections. He failed to get the support from fellow engineers and Tepco executives for changes that would add to the cost....