BASIC CONCEPTS AND PRINCIPLES OF ASSESSMENT: A REVIEW OF THE ADVISORY COMMITTEE REPORT ON THE BIOLOGICAL EFFECTS OF IONIZING RADIATION. The present concepts of a single upper limit for individual and population doses, with the understanding that the risks should be kept as low as practicable, may not be adequate for the future uses of nuclear radiation. This is because of the potential for exposing large populations from the uses of nuclear power and medical radiation. There is a need to compare the biological risks and benefits of radiation applications and its alternatives. The recommendations of the US National Academy of Sciences — National Research Council's Advisory Committee on the Biological Effects of Ionizing Radiation (BEIR) are presented. The Committee estimates of the genetic, somatic and ill health risks from population exposures of 170 mrem are included.