Abstract
Nuclear techniques for direct assessment of internally deposited radionuclides are essential for monitoring and dosimetry of members of the public exposed due to radiation accidents. Selection of the methods for detection of internal contamination is determined by nuclear-physical characteristics of the deposits. For the population living in settlements located along the Techa River contaminated in 1950s by liquid radioactive wastes from the plutonium production complex Mayak (Southern Urals, Russia) the main dose-forming radionuclide was 90Sr. It is a bone-seeking radionuclide that incorporates in the skeleton and remains there for many years so it can be detected for long periods after the intake occurred. Measurements of pure beta-emitting 90Sr are possible through detection of bremsstrahlung from the 90Sr/90Y beta rays in the low energy range (30-160 keV) using phoswich detectors. This suggested the development of a unique whole body counter in 1974 for monitoring of the 90Sr- and 137Cs-body burden in the Techa River population with the use of phoswich detectors. Long-term observations with the WBC covering more than 38,000 measurements on over 20,000 people have been made. This has created a unique database for studying strontium and calcium metabolism and for assessment of the internal dose for residents of the Techa River settlements due to ingestion of 90Sr. This paper describes the main results obtained for the Techa River population essential for bone metabolism and dosimetry, epidemiological studies, and radiation protection.