Naturally occurring radiation sources: existing or planned exposure situation?

After more than fifteen years of application, ICRP Publication 60 has been revised. The revision was based upon the concept of 'controllable dose' as the dose or sum of doses to an individual from a particular source that can reasonably be controlled by whatever means. The new recommendations have been published as ICRP Publication 103. The European Basic Safety Standards as well as the International Basic Safety Standards are currently under revision as a result of the new recommendations from ICRP. According to the ICRP, there have been indications that some changes to the structure and terminology of the system of protection were desirable in order to improve clarity and utility. In particular the distinction between practices and interventions may not have been clearly understood and the ICRP now recognises three types of exposure situations, which replace the previous categorisation into practices and interventions. These exposure situations are intended to cover the entire range of exposure situations: (1) planned exposure, (2) existing exposure and (3) emergency exposure. There are situations of exposure to naturally occurring radiation sources in different occupations, e.g. exposure to radon and radon progeny in workplaces other than where the exposure is required by or is directly related to the work and aircrew exposed to cosmic radiation. In the European (Euratom) and the International Basic Safety Standards, these exposure situations are treated conceptually different-either as a planned exposure situation or as an existing exposure situation. This note reviews the change of exposure situations from Publication 60 to Publication 103 and the implications for the revision of both the International and the European Basic Safety Standards. The paper draws some conclusions on the classification of the exposure situations in the two basic safety standards based on a logical interpretation of the ICRP recommendations. It is recommended that the European and the International Basic Safety Standards should be harmonised to avoid confusion among users of the standards.