PRUDENCE AND CONSERVATISM IN RADIATION PROTECTION: A CASE STUDY.

Prudence is a cornerstone of radiation protection philosophy. However, whilst the concept is clearly valid at the level of principle, it is nonetheless necessary to ask 'How should prudence be applied in the context of various practical situations.' This is perhaps particularly important where exposures are low-within the range of natural background, where changes in the level of protection will have no meaningful impact whatsoever on the overall exposure level of any individual. The concept of prudence is applied at a 'top tier' level through the application of the Linear No Threshold hypothesis. In day-to-day protection considerations, including many types of dose assessments, the concept of prudence has translated into the need to take a conservative approach. This paper considers the combined impact of accumulated layers of conservatism, using the example of clearance as a case study. It concludes that doses actually resulting from the clearance process are typically more than two orders of magnitude below the internationally agreed objective of 'some tens of µSv y-1', which was itself established on the basis of considerable prudence. The implications of this outcome are discussed.