Effect of Uncertainty in Transfer Rates for the ICRP Publication 67 Biokinetic Model on Dose Estimation for 239Pu from Results of Individual Monitoring

Abstract

The radiation dose due to internal exposures from 239Pu is mainly estimated by measuring actual urinary or faecal excretion of activity and comparing those values with the standard excretion rates calculated from the models of the International Commission on Radiological Protection (ICRP). Recently, on the other hand, uncertainties in the ICRP's models and parameters are under consideration because of the paucity of human data. In addition, there is a possibility of variation between individuals. A code has been developed to reproduce the ICRP's dose coefficients and excretion rates for 239Pu, which is one of the most important elements for occupational exposure. By using this code, the respective transfer rates for the ICRP Publication 67 biokinetic model were modified, and the effect owing to these changes on present hazard assessment was investigated. As a result, it was shown that dose estimates for workers exposed to 239Pu were not very sensitive to changes in these transfer rates.

Eurados review of retrospective dosimetry techniques for internal exposures to ionising radiation and their applications

“…In addition to all the limitations indicated so far, one must consider that in the case of internalization of radionuclides, and even more in mixed internal exposures, an adequate assessment of uncertainties can be hugely complex and requires a detailed formal consideration of the total uncertainty budget on a case by case basis. The key sources can be identified in the paucity of human data and in the potential inter-individual variation (Suzuki et al 2002 ; Paquet et al 2016 ). Nevertheless, formal or even informal assessments, where information is lacking, are essential to ensure the quality and validity of the dose estimation techniques applied (Ainsbury et al 2014 , 2018 ).…”