The three key principles of radiological protection are justification, optimization

and dose limitation.

These principles are defined as follows:

1 The Principle ofJustification — Any decision that alters the radiation exposure situation should do more good than harm.

2 The Principle of Optimization of Protection — The likelihood of incurring exposure, the number of people exposed, and the magnitude of their individual doses should all be kept as low as reasonably achievable, taking into account economic and societal factors.

3 The Principle of Application ofDose Limits — The total dose to any individual from regulated sources in planned exposure situations other than medical exposure of patients should not exceed the appropriate limits specified by the ICRP.

The principles of justification and optimization apply in all three exposure situations whereas the principle of application of dose limits applies only for doses expected to be incurred with certainty as a result of planned exposure situations.

Exposure categories

Three categories of exposure are distinguished: occupational exposures, public exposures, and medical exposures of patients (and comforters, carers, and volunteers in research). This chapter is concerned with radiation protection in the nuclear fuel cycle and so the emphasis is on occupational and public protection in planned and emergency exposure situations.