MWDS-2016: THE SLOW DISSOLUTION RATE FOR PLUTONIUM NITRATE INTAKES AT THE MAYAK FACILITY

Journal Article · Sun Jan 20 23:00:00 EST 2019 · Radiation Protection Dosimetry

DOI:https://doi.org/10.1093/rpd/ncy296· OSTI ID:1580164

Bull, R. K. ^[1]; Puncher, M. ^[2]

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1. Nuvia Limited, Didcot, Oxon, UK
2. Public Health England, Chilton, Didcot, Oxon, UK

Abstract

The slow dissolution rate of material deposited in the lung plays a key role in determining the eventual radiation dose received by the lung. It is therefore of great importance to establish a reliable value for this parameter, to incorporate into the latest Mayak Worker Dosimetry System (MWDS-2016). Disparate values have been obtained for the slow dissolution rate of plutonium nitrate. A volunteer study performed by Public Health England (PHE) and an analysis of United States Transuranium and Uranium Registries (USTUR) case 0269 have yielded slow dissolution rates in the region of 10–40 × 10−4 d−1. However, autopsies performed on 20 Mayak workers, exposed predominantly to nitrates, have resulted in estimates of slow dissolution rates of around 2.4 × 10−4 d−1. Three hypotheses have been proposed to explain this discrepancy: (1) a slower dissolution rate in the interstitium, (2) a third exponential component in the dissolution function and (3) a small component of oxide in the aerosol to which Mayak ‘nitrate’ workers were exposed. This paper describes tests of these competing hypotheses. Bayesian methods have been applied to the following datasets: PHE volunteer data; Beagle dog data; USTUR cases and Mayak worker data. It is concluded that a mixture of oxide and nitrate material, with the oxide forming ~14% of the intake, best describes the Mayak dissolution rate, without introducing values for other parameters which conflict with other studies.

• Sponsoring Organization: USDOE
• OSTI ID: 1580164
• Alternate ID(s): OSTI ID: 22900218
• Journal Information: Radiation Protection Dosimetry, Journal Name: Radiation Protection Dosimetry Journal Issue: 2 Vol. 185; ISSN 0144-8420
• Publisher: Oxford University Press
• Country of Publication: United Kingdom
• Language: English