The inventor Henry Bessemer discovered that directing a blast of air at melted iron in a furnace would burn out the impurities that made the iron brittle.

The 300 holes in each blade, most of them thinner than a human hair, are engineered to spread a coat of cool air over the spinning blades so they aren't melted by 3,000f exhaust gases.

Japanese experts say the fuel rods inside the reactor were fully exposed to the air and melted.