Effective dose of internal irradiation for residents of the most contaminated areas of Bryansk and Kaluga oblasts

Measurements of the ^134,137Cs content in the bodies of the residents of the most contaminated areas of Bryansk and Kaluga oblasts have been performed since 1986. Data which make it possible to evaluate the individual and average effective dose of internal irradiation have been obtained. The work has been supported by calibration and verification of the measurement means and methods. It has been established that the individual dose is described by a nearly log-normal distribution with a long “tail” at doses substantially above the average and median values. This indicates the existence of groups with an elevated radiation risk so that these groups should be treated first when preventative-medical and protective measures are taken. It is shown that for the most highly contaminated regions of Bryansk and Kaluga oblasts most of the effective dose of internal irradiation is formed over a period of 8–10 years after the accident. __________ Translated from Atomnaya énergiya, Vol. 103, No. 3, pp. 192–197, September, 2007.