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- Nuclear fission: splitting atoms
- giving off extraordinary amounts of (steam producing) heat
- huge unstable atoms are hit with neutrons (usually of radioactive uranium 235)
- Process releases energy & more neutrons
- Neutrons hit other uranium atoms
- chain reaction
Nuclear fuel rods inside a power station
- Control rods (neutron absorbing material) can be raised or lowered between the fuel rods to control the reaction
- Reactors are cooled by the same water used to moderate the fuel cycle
- Fuel rods are inserted into water to make superheated, high pressure steam (300 C)
- Steam is radioactive
- a closed loop heat exchanger is used to transfer heat to non radioactive water
Nuclear meltdown & melt-through
- meltdown
- fuel rods overheat
- leaves a molten mass of fuel and fission products at the bottom of the reactor vessel (in the casting)
- melt through
- molten fuel and fission products leak through the casing into the environment
Nuclear power generation summary
- Uranium fuel rods, bombarded with neutrons which break apart U 235 atoms (fission)
- Reaction releases large amounts of heat
- Water directed through heat to make steam
- Steam turns turbine connected to generator
