Protection against enhanced levels of natural radiation: concepts and regulatory approaches

摘要

In the recent years, exposures to enhanced natural radiation came into the focus of radiation protection. A variety of exposure types have to be taken into consideration. Any regulation of enhanced exposures to natural radiation sources may have large social, economic and political consequences. Unfortunately, there has been little or no international harmonisation yet, and a comprehensive, systematic approach totally consistent with regulation of artificial sources seems not to be achievable in the next few years. However, consistency should be striven for in the approaches to different types of exposures to enhanced natural radiation. In the European Basic Safety Standards, "work activities," within which the "presence of natural radiation sources leads to a significant increase in the exposure of workers or members of the public which cannot be disregarded from the radiation protection point of view," are regulated separately from practices and interventions. It is shown how a recommended regulatory four-step procedure may be applied to the inclusion of the different exposure types in the radiation protection system. Criteria for solving at least some of the problems of control of enhanced natural radiation exposures within the future radiation protection legislation in Germany are discussed. In particular, approaches to regulate occupational exposure to cosmic radiation, to radon progeny and to NORM, public exposure to NORM residues in relation to residues from former mining and milling activities in connection with restoration programmes, and public exposure to radon in dwellings are discussed in detail. The still controversial problem of how radon should be evaluated is discussed as well.