Ionising radiation

• Uses of ionising radiation

  INDUSTRY:

  • test rock porosity in oil/gas exploration
  • strengthen polymers by creating cross- links in molecules

  HEALTHCARE:

  • cancer treatment

  NUCLEAR FISSION/FUSION

  • Nuclear weapons
• Risk Benefit Analysis

  • symptoms may take too long to develop, esp.from chronic exposure to low doses
  • benefitters and those at risk from activity may be in different locations ( nuclear elec. users and uranium miners)
• Sources of Ionising radiation

  NATURAL:

  Sun- charged sub atomic particles reach atmosphere, then absorbed releasing high energy EM radiation

  Ground radon - uranium atoms decay, radon produced and releases Alpha radiation which travels up cracks and escapes into atmosphere

  ANTHROPOGENIC:

  Occupational- nuclear elec. generation, aircraft flight crews, mining

  Consumer products - smoke detectors, camping gas mantles contain radionuclides
• Alpha radiation

  • travels short distances
  • low penetration - absorbed by clothing
  • high absorption - dangerous if ingested as particles are absorbed in tissue
• Beta radiation

  • travels medium distances
  • moderately absorbed
  • sources near body still pose risk
• Gamma radiation

  • travels long distances
  • not easily absorbed - lower danger
• Factors that affect impacts - Half life

  Time taken for half of original isotope to decay

  • Isotopes with short HL release all their radiation quickly, more dangerous (more emissions) but not for long
  • Isotopes with longer HLs emit small amounts and are less dangerous
  • HLs of decades ( medium HL) are concerning, high rate of release and last for most of peoples lives.
• Control of exposure

  STRATEGIES:

  • Enclosed radioactive source
  • materials to absorb radiation
  • protective clothing
  • distance from source
  • decontamination
• High level waste management

  VITRIFICATION:

  • solid waste mixed with molten glass, solidifies in steel containers surrounded by concrete. Air cooling removes heat from radioactive decay.
• Intermediate level waste - management

  Metal tubes that surround the rods and filters from waste repossessing. Mixed with cement and stored in steel drums.
• Low level solids - management

  Sealed in thick polythene bags, inside steel drums, inside steel containers in concrete lined landfills
• Low level liquids - management

  Waste solutions from used fuel reprocessing and storage. Filtered,(ion exchange) then discharged
• Low level gases - management

  Emmisions from used fuels in storage and reprocessing. Filtered and released.