Nuclear Power

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  • Nuclear Power
    • Large amounts of energy are released when small amounts of matter from the nuclei of atoms are destroyed.
    • Nuclear fission involves the splitting of nuclei of fissile fuels that have large atoms, such as the isotopes uranium 235 and plutonium 239
      • Only nuclear fission is commercially viable at the moment.
    • Nuclear fusion involves the joining of the nuclei of small atoms, such as the isotopes hydrogen 2 and hydrogen 3
      • Nuclear fusion is still only a research project
    • Factors that have limited the growth of nuclear power
      • The technology is very complex so it is difficult to use in less technologically advanced societies
      • The complex technology makes it very expensive
      • There is strong public opposition in some countries
        • This is because of the possible link with nuclear weapons and concerns over health and safety
      • There is uncertainty over the long term disposal of radioactive waste
      • Uncertainty over the total costs of nuclear power since no commercial reactor has been fully decommissioned
    • The future
      • The high energy density of nuclear fuels means that reactors require very little fuel. Power stations, therefore, can be located where the transport of large amounts of fuels with a lower energy density would be a problem.
    • Available resources
      • A huge amount of uranium exists but most is found in very low purity ores, which cannot be economically exploited.
    • Level of technological development
      • Uranium 238 is over 100 times as abundant as uranium 235 but it cannot be used in normal reactors. The technology is more complex and therefore more expensive
      • The fusion of hydrogen nuclei releases the huge amounts of energy produced in the Sun. Controlled fusion of hydrogen has been achieved on Earth but the technology is very complex and is many years away from commercial use.
    • Economic Issues
      • The decision to use nuclear power did not include accurate estimates of the total cost of decommissioning, which are still unknown.
    • Environmental Impacts
      • Radioactive waste
        • Radioactive wastes from fuel manufacture
        • Waste fuel after use in the reactor
        • Anything that has become contaminated by contact with the fuel
          • Protective clothing, tools and processing equipment
        • Materials that have been exposed to neutrons from the chain reaction and developed activation products
          • Fuel rod cases, reactor components
        • Radioactive wastes are catergorised according to the level of radiation they emit and whether they generate heat.
          • As long as the waste is contained in sealed containers with adequate absorbing materials or space so the radiation released does not affect the workers or public then waste storage is safe.
          • High level waste includes used uranium fuel rods and can only be stored by vitrification.
            • This is where dried powdered solid waste is mixed with molten glass and allowed to solidify in stainless steel containers, surrounded by concrete to absorb radiation. Air cooling removes the heat of radioactive decay.
          • Intermediate level waste includes the metal tubes that surround the fuel rods.
            • The waste is mixed with cement and stored in stainless steel drums.
          • Low level waste can be solid, liquid or gas.
            • Solid waste includes contaminated equipment and  clothing and is sealed in thick polythene bags, inside steel drums, inside steel truck containers in concrete lined landfill sites
            • Liquid waste includes waste solutions from used fuel reprocessing and storage. It is filtered, including ion exchange, then discharged.
            • Waste in a gaseous state includes gases released from used fuel during storage and reprocessing. It is filtered then released.


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