Lesson 6 6.14 Worked Example -- Dose Calculation for Decommissioning

The worker would receive a dose of 44.4 microSv (0.0444 mSv), which is:

  • Well below the public dose limit of 1 mSv/yr
  • Well below the occupational dose limit of 20 mSv/yr
  • However, the ALARP principle still applies — the worker should consider whether the time or distance can be increased to further reduce the dose

Key learning point: The inverse square law shows that increasing distance from a source is a very effective way to reduce dose. Doubling the distance reduces the dose rate by a factor of four. In this example, moving from 1.0 m to 1.5 m reduced the dose rate from 50 to 22.2 microSv/h — a reduction of more than 55%.