Kernbrennstoff
Nuclear fuel is any material that is consumed to derive nuclear energy. Technically speaking, all matter can be a nuclear fuel because any element under the right conditions will release nuclear energy, but the materials commonly referred to as nuclear fuels are those that will produce energy without being placed under extreme duress. Nuclear fuel is a material that can be 'burned' by nuclear fission or fusion to derive nuclear energy. "Nuclear fuel" can refer to the fuel itself, or to physical objects (for example bundles composed of fuel rods) composed of the fuel material, mixed with structural, neutron moderating, or neutron reflecting materials.