Internal radioactivity monitoring

Some problems obtained by radiation protection practices is presented. As for the regulations in Japan, there are some ambiguities in details among three laws of reactor control, radiation control and ionizing radiation damage prevention, and decisions are sometimes required for health physicist in radiation facilities. ICRP recommendations are employed as a basis for practical radiation control and some interpretations are made on classification of radiation work condition, necessity of air monitoring of work area or personal monitoring, kinds of internal monitoring such as routine or special examination and its examinee, monitoring criteria such as investigation level or derived investigation level in the case of routine or special monitoring, monitoring procedure and plan in general. It is further presented in this review on problems of research and development for internal radiation exposure control. These are development of measurement method of radiation or radionuclides such as tritium, dose assessment and its employable parameter acquisition, and problems concerning to practical radiation protection management and procedures especially for internal exposure. Experiences in JAERI Tokai Laboratory are shown on this matter. It is clarified by the above-written understandings that research and development on items of internal exposure and its dose assessment should be extensively carried out. (Takagi, S.)