Criteria for limiting radiation risks to the public

Abstract

This paper is concerned with the radiological protection criteria used for setting limits to public radiation risks. It describes the formal basis of the criteria in current use with extensive reference to the recommendations used to formulate statutory limits. Attention is drawn to the limitations of the present concepts for use in estimating risks, and brief comments are made on likely future developments.

It is shown that the current concepts used for defining acceptable industrial augmentations to the radiation environment of the general public are derived from a formalized set of dose limits. These dose limits do not provide an index of risk, furthermore the practical criteria used to supplement them are intended only to ensure that doses received do not exceed the limits. The practical criteria do not provide a means of adequately estimating doses received or risks incurred.

Properly applied, with experience and professional judgement, the present criteria are useful in setting norms of good practice in design and operation. Because of inconsistencies in the dose limits, and the assumptions and approximations in estimating potential doses, any practical rules are necessarily imprecise, and a factor of safety is applied when it is necessary to be certain of working within statutory limits.

The numerical interpretation of concepts based on dose limits will undergo continuous development mainly by advances in knowledge of the pathways to man, human metabolism, and in the mathematical procedures used for deriving organ doses from this data. However, the quantification of risks to populations involves eliminating ambiguities in dose-risk relationships which are orders of magnitude greater than the error in dose estimations.