Dangers of Radiation

Dangers, monitoring, dosage and safe use of ionising radiation

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  • Created by: Ciara
  • Created on: 08-03-13 18:05

Dangers...

(Includes: A, B, G, protons, neutrons & Xrays)

Ionising Radiation hazardous because it damages living cells by:

  • Destroying Cell membranes; killing the cells.
  • Damaging vital molecules (i.e. DNA) directly.
  • Damaging indirectly by producing 'Free radical ions' which react with vital molecules, which damages cell nuclei and causes uncontrollable cell division& growth which is the cause of tumors that could be cancerous. (Somatic effect)
  • (Genetic effect): damaged DNA in sex cells can cause mutations that could be inherited in future generations. 
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Monitoring...

Film Badges

  • People who use equiptment that produces ionising radiation must wear a film badge to monitor exposure.
  • Exposure to each form of ionisation is then estimated from the blackening of the film when developed.
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Dose and Limits...

DOSE:

  • Biological effects from ionising radiation depend on the dose; which is measured in terms of energy absorbed per unit mass of matter from the radiation.
  • The same dose of two different types of ionising radiation (A, B, G etc...) have different effects.
  • 'A' radiation produces more ions per millimeter than 'G' in the same substances so is more damaging BUT 'A' radiation from a source outside of the body can't penetrate skin so less damage than if it were inside the body.

LIMITS:

  • Every dose has a dose equivilent in Sieverts (Sv), which is the dose due to 250KV Xrays that would have the same effect: 1mSv of 'a'has the same biological effect as 10mSv of 250KV Xrays.
  • Maximum permissible exposure limit for annual dose equivilent: recommended limit is 15mSv.
  • Average dose of equivilent for a radiation worker is 2mSv.
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Background Radiation...

Occurs naturally due to:
(Descending in average radiation per year)

  • Air (radon gases etc...)
  • Medical uses
  • Ground & Buildings
  • Food & Drink
  • Cosmic Rays
  • Nuclear Weapons
  • Air Travel
  • Nuclear Power

And varies with respect to geography (Geological features!)

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Safe use of Radioactive Materials

1.Storage: 

  • Lead lined containers- Most sources produce gamma radiation aswell as Alpha & Beta, so lining must be thick enough to reduce Gamma radiation to roughly background level.
  • Regulations require containers to be kept under 'lock & key'.

2.Using Radioactive Material:

  • No source can come into contact with skin
  • should be transfered using handling tools (robots, long tongs, glove boxes), so the source is ALARA (As low as reasonably achievable) 
  • Liquid, gas & powders are kept in sealed containers, so radioactive gas can't be inhaled; liquid can't be spashed or drunk.
  • Radioactive sources shouldn't be used beyond necessity- more exposure= greater dose recieved.
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