Dangers of Radiation

• Ionising nuclear radiation can damage living things such as human cells and tissues at high doses:
• This can include:

  • Cell death
  • Mutations
  • Cancer
• If the atoms that make up a DNA strand are ionised, then the DNA strand can be damaged

  • If the DNA is damaged, then the cell may die, or the DNA may be mutated when it is replicated
  • If a mutated cell replicates itself then a tumour may develop
  • This is an example of cancer, which is a significant danger of radiation exposure
• Diagram showing the damage caused to DNA by ionising radiation. Sometimes the cell is able to repair the DNA during replication successfully, but incorrect repairs can cause a mutation

  A) ionising radiation

  B) damaged

  C) replicated

  D) mutation

  E) mutation

  
• Acute radiation exposure can have other serious symptoms:

  • It can cause skin burns, similar to severe sunburn
  • Radiation can reduce the amount of white blood cells in the body, making a person more susceptible to infections by lowering their immune system
  • Because of this, it is very important to handle radioactive sources carefully
• Radioactive materials are moved, used and stored in a safe way
• The risks associated with handling radioactive sources can be minimised by following a few simple procedures:

  • Store the sources in lead-lined boxes and keep them at a distance from people
  • Minimise the amount of time you handle sources and return them to their boxes as soon as you have finished using them
  • During use, keep yourself (and others) as far from the sources as possible.
  • When handling the sources do so at arm’s length, using a pair of tongs
• Radioactivity warning sign

  
• Radioactive materials such as used nuclear fuel are transported in special containers called casks

  • These casks can withstand extreme conditions such as fire, cold and being submerged in water
• If an isotope has a long half-life then a sample of it will decay slowly

  • Although it may not emit a lot of radiation, it will remain radioactive for a very long time
• Sources with long half-life values present a risk of contamination for a much longer time
• Radioactive waste with a long half-life is buried underground to prevent it from being released into the environment
• Radioactive waste with long half-lives is buried deep underground
• Safety precautions for all ionising radiation include:

  • reducing exposure time
  • increasing the distance between the source and living tissue
  • using shielding to absorb radiation
• Limiting the amount of time spent near a radioactive source reduces the amount of radiation dose received
• The amount of radiation received by a person is called the dose and is measured in sieverts (Sv)

  • One sievert is a very big dose of radiation
  • It would cause acute radiation poisoning
• Increasing the distance the radiation is away greatly reduces the size of the dosereceived

  • Using tongs instead of your hand when handling a radioactive source can help with this
• Constructing nuclear power plants in remote areas increases their distance from people if there is a problem
• Burying nuclear waste far from places where people live also increases the distance to people
• Radiation shielding is a barrier placed between a radiation source and a person or area to protect them

  • The purpose of shielding is to limit exposure to radiation at a certain location or time
• Barriers absorb the energy from radioactive sources
• Barriers are normally made of lead, water or concrete

  • People handling radioactive sources should wear a lead apron to reduce their exposure
• When X-rays are taken:

  • the area around where the image is needed is shielded
  • the radiologist stands behind a barrier or leaves the room
• A radiologist can stand behind a lead barrier to reduce the amount of radiation they are exposed to