The ICRP protection policy. The conceptual framework of radiation protection

Within twelve months of the discovery of X-rays in 1895, it was reported that large doses of radioation were harmful to living human tissues. The first radiation protection standards were set to avoid the early effects of acute irradiation. By the 1950s, evidence was mounting for late somatic effects -mainly a small excess of cancers - in irradiated populations. In the late 1980s, sufficient human epidemiological and had been accumulated to allow a comprehensive assessment of carcinogenic radiation risks following the delivery of moderately high doses. Workers and the public are exposed to lower doses and dose-rates that the groups from whom good data are available so that risks have had to be estimated for protection purposes. However, in the 1990s, some confirmation of these risk factors has been derived from occupationally exposed populations. If an estimate is made of the risk per unit dose, then in order to restrict the doses that people receive, levels of acceptable risk must be estabilished for both workers and the public. There has been and continues to be a debate about the definitions of 'acceptable', 'unacceptable' and 'tolerable' and the attributing of numerical values to these definitions. The values differ as between normal operations, the potential for accidents, recovery of contaminated land, and for workers or the public. This paper discusses the issues involved in the quantification of these terms and the way in which the International Commission on Radiological Protection has used acceptability of risk in setting its new standards for protection. (orig.)