Consideration on the critical group, with respect to radioactive waste management

In this paper the concept of critical group is regulated following the historical flow and evolved to concrete application field. In the consideration of radiation protection to the member of public, the direct pickup of individual is scarce. In such a case, the concept of critical group is usually used, which is a concept of group handling of public radiation protection. Critical group is defined as a small group having homogeneous factors, i.e. age, dietary habits etc., which affect the estimation of radiation dose, and represent an individual who is expecting to receive the highest dose in the population. Critical group is usually used as an important concept in case of the estimations of nuclear facility siting and safety of radioactive waste disposal. This concept is used for dealing with a population from a part of the public radiation protection, coping with the concept of collective dose. As a result of investigation and discussion, the points and subjects are summarized as follows: (1) evolution of critical group concept in ICRP, IAEA etc., (2) concrete examples of critical group concept application, (3) especially, application of critical group concept in the field of radioactive waste management. (author)