The machine that makes nuclear fuel cheap was designed by a prisoner: Gernot Zippe was an Austrian engineer captured by the Soviets in 1945. He spent a decade in a detained research group where his team worked out the design of the modern gas centrifuge: a thin rotor spinning on a needle bearing, held by a magnet, consuming almost no power. Released in 1956, he was allowed to leave but not to take a single document, so he reconstructed the design from memory in the West, and his architecture became the basis of Europe's enrichment industry. The efficiency gap was amazing - Centrifuges enrich uranium using roughly fifty times less electricity than the gaseous diffusion plants America ran at the time. Diffusion plants were so power hungry that they consumed entire power stations worth of energy. Diffusion is now extinct; the last US plant closed in 2013. Thanks largely to Zippe's rotor, enriched uranium is cheap enough that fuel is a minor line item in the cost of nuclear electricity.