RESUMO
The purpose of this paper is to present (1) the method of assessing the contribution of short-lived radioiodines to the thyroid for members of the public in Fukushima and neighbouring prefectures based on available data and (2) the results of a realistic assessment of such a contribution. The estimates of that contribution for the inhalation intake that occurred on the day of the main fallout (15 March 2011) are within 15 % of the dose to the thyroid from (131)I. The contribution to the thyroid dose from intake of (132)Te is higher than that from the intake of (133)I by a factor of â¼3. The contribution of short-lived radioiodines to the thyroid dose for the public in the case of inhalation intake occurring as early as March 12 might be as great as 30-40 %.
Assuntos
Acidente Nuclear de Fukushima , Radioisótopos do Iodo/farmacocinética , Modelos Biológicos , Cinza Radioativa/análise , Radiometria/métodos , Glândula Tireoide/metabolismo , Absorção de Radiação/fisiologia , Administração por Inalação , Simulação por Computador , Meia-Vida , Humanos , Radioisótopos do Iodo/administração & dosagem , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
An example of a numerical method application for minimum detectable annual dose calculation that can be guaranteed by the operating monitoring programmes for plutonium and uranium is presented. The method analyses the frequency distribution for a total number of counts obtained in n measurements performed during n monitoring intervals that are inside the calendar year. Urine sample radiometric measurement technique for plutonium and uranium operating monitoring programmes is investigated, showing dependences of the detection limits on the frequency of measurements, on number of calendar years under observation and on the activity median aerodynamic diameter (AMAD). Only a probability density function (PDF), for the background number of counts, stochastic variability of urine excretion and uncertainty of the intake pattern were taken into account as the main variables influencing the calculated detection limits. But there is no limitation for the proposed method to include the variability of other influencing model parameters in the calculation procedure.
