Uncertainties Analysis for the Plutonium Dosimetry Model, Doses-2005, Using Mayak Bioassay Data

Abstract

The Doses-2005 model is a combination of the International Commission on Radiological Protection (ICRP) models modified using data from the Mayak Production Association cohort. Surrogate doses from inhaled plutonium can be assigned to approximately 29% of the Mayak workers using their urine bioassay measurements and other history records. The purpose of this study was to quantify and qualify the uncertainties in the estimates for radiation doses calculated with the Doses-2005 model by using Monte Carlo methods and perturbation theory. The average uncertainty in the yearly dose estimates for most organs was approximately 100% regardless of the transportability classification. The relative source of the uncertainties comes from three main sources: 45% from the urine bioassay measurements, 29% from the Doses-2005 model parameters, and 26% from the reference masses for the organs. The most significant reduction in the overall dose uncertainties would result from improved methods in bioassay measurement with additional improvements generated through further model refinement. Additional uncertainties were determined for dose estimates resulting from changes in the transportability classification and the smoking toggle. A comparison was performed to determine the effect of using the model with data from either urine bioassay or autopsy data; no direct correlation could be established. Analysis of the model using autopsy data and incorporation of results from other research efforts that have utilized plutonium ICRP models could improve the Doses-2005 model and reduce the overall uncertainty in the dose estimates.

Radiation Effects on Mortality from Solid Cancers Other than Lung, Liver, and Bone Cancer in the Mayak Worker Cohort: 1948–2008

“…Estimation of solid cancer risk resulting from prolonged occupational external gamma-exposure is complicated by the fact that radiochemical and Pu production plant workers were potentially exposed to Pu-containing aerosols. We have provided external dose risk estimates that are adjusted for Pu exposure, but this adjustment is limited by several factors: 1) only about 40% of the workers with potential for Pu exposure have urine-bioassay data; 2) routine monitoring did not begin until many years after the largest exposures and appears to have depended on health status; 3) Pu dose estimation from bioassay data is complicated and the resulting estimates have large uncertainties; and 4) the Pu-exposure-potential categories used prior to bioassay-based dose estimates imprecisely characterize Pu exposures [10–12,21,33]. The uncertainties and limitations of the Pu dose and surrogate categories could result in some bias in the external dose estimates.…”

Ischemic Heart Disease in Workers at Mayak PA: Latency of Incidence Risk after Radiation Exposure

“…Secondly, dose estimates are based on measurements. Therefore, although the error is rather large in the case of internal alpha exposures[31], it can be expected to be non-differential. Furthermore, regular medical surveillance is achieved due to annual examinations in the polyclinic for all employees and former employees still living in Ozyorsk.…”

“…Thus, internal radiation burden is lifelong. Finally, uncertainty in internal doses is rather large [31].…”

The “Clinic” Medical-Dosimetric Database of Mayak Production Association Workers: Structure, Characteristics and Prospects of Utilization

“…These dosimetry papers are mainly based on the findings from the Russian Federation-United States of America § All of the descriptive data are given here and subsequently are for the cohort of workers first employed at Mayak during 1948 -1958. (RF-US) project 2.4 "Development of the Improved Dosimetry System for Workers at Mayak Production Association" funded by the U.S. Department of Energy (DOE) (Bess et al 2007;Krahenbuhl et al 2002;Leggett et al 2005;Smetanin et al 2007a and b;Vasilenko et al 2007a and b). It should be noted that the latest improved dose estimates based on the Mayak "Doses-2005" dosimetry system were used in this paper.…”