An attempt to explain the risk to the Fukushima nuclear plants following the earthquake: The plants are designed to shut automatically, which halts the main nuc

An attempt to explain the risk to the Fukushima nuclear plants following the earthquake: The plants are designed to shut automatically, which halts the main nuclear fission reaction, but there is a residual amou ntense heat within the system. Back-up generators should kick in to power the coolin mechanisms needed to dissipate that heat - b they fail, as appears to have happened here, temperatures rise. If this isn't stopped, the reactor vessel itself could eventually melt an eak. Right? Has anybody found any documents if Japan has been notified or warned about these backup systems of these plants? It sound like a design failure to me. (I know nothing about nuclear power plants)