Magnox fuel rod, c 1968.
© Science Museum / Science & Society Picture Library
These fuel rods have a key role in the workings of magnox nuclear power stations. The rods are long bars of natural uranium clad in magnox, a magnesium alloy. The rods fit into vertical slots in the core of the reactor, and help the proces of fision. During fision, energy is released and the reactor heats up. Carbon dioxide gas is pumped in to cool the reactor and then piped to a boiler where it heats water. The steam this produces is then used to drive electricity generators.