Closing the loop on the nuclear fuel cycle is a long-cherished dream of the nuclear energy industry. Just like medieval alchemists toiling over their vials in hopes of finding the recipe of turning lead into gold, or inventors racking their brains over the designs of perpetual motion machines, the nuclear power industry, time and again, strives to build a magic reactor that would breed its own fuel. Just imagine: you load fresh fuel into the reactor; the fuel burns, generating power for millions of consumers; its resource is gradually running out… but wait! It’s a miracle!… the fissile material is not only not depleting, but the reactor is actually making more! You unload the fuel, a few tweaks here and there, and there you go: a fresh fuel load. What could be better? Only, maybe, the Fountain of Youth. But the magic in fairy tales has no price: It’s a hero’s reward for wit and valor. With the looped-up nuclear fuel cycle, however, the price is clear: generation of highly toxic, weapons-grade plutonium, super-expensive safety measures needed for spent fuel reprocessing, and risks of massive accidents wreaking more damage than heretofore was known to man. Above: Distillatio, scene in an alchemist laboratory, by Jan van der Straet, late 16th cent. (Source: Wikimedia Commons).