DEVELOPMENT OF AN INHALATION INTAKE MODEL FOR ~(241)Am BASED ON MAYAK PRODUCTION ASSOCIATION WORKER DATA

摘要

Americium-241 is a significant radiation hazard at facilities that handle or reprocess spent nuclear fuels. An inhalation intake model for ~(241)Am was developed using autopsy data obtained from former workers at the Radiochemical and Plutonium Production Plants at the Mayak Production Association (Mayak PA), Ozyorsk, Russia. Accumulation of ~(241)Am in the body can occur though direct exposure to ~(241)Am (termed here "exogenous" exposures), usually as an inhaled aerosol, or though exposure to ~(241)Pu that decays inside the body to ~(241)Am (termed here "endogenous" exposures). Metabolism of endogenous and exogenous ~(241)Am can differ, with endogenous ~(241)Am being initially related to the behavior of ~(241)Pu. For the model, it was assumed that intakes of ~(241)Am and ~(241)Pu were functionally associated with intakes of ~(239)Pu. The current Mayak Worker Dosimetry System model (MWDS-2008) was used to describe metabolism of plutonium and americium in the respiratory tract. The ICRP-30 model was used for the gastrointestinal tract, the ICRP-67 model was used for metabolism after absorption into the blood for americium, and the "Leggett modification" of the ICRP-67 model for plutonium was used for systemic, non-pulmonary organs. The proposed inhalation intake model for americium provides estimates for internal doses from ~(241)Am from both exogenous and endogenous sources.