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Smith R, Ellender M, Guo C, Hammond D, Laycock A, Leonard MO, Wright M, Davidson M, Malard V, Payet M, Grisolia C, Blanchardon E. Biokinetics and Internal Dosimetry of Tritiated Steel Particles. Toxics 2022; 10:toxics10100602. [PMID: 36287882 PMCID: PMC9607624 DOI: 10.3390/toxics10100602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/05/2022] [Accepted: 10/06/2022] [Indexed: 05/14/2023]
Abstract
Decommissioning fission and fusion facilities can result in the production of airborne particles containing tritium that could inadvertently be inhaled by workers directly involved in the operations, and potentially others, resulting in internal exposures to tritium. Of particular interest in this context, given the potentially large masses of material involved, is tritiated steel. The International Commission on Radiological Protection (ICRP) has recommended committed effective dose coefficients for inhalation of some tritiated materials, but not specifically for tritiated steel. The lack of a dose coefficient for tritiated steel is a concern given the potential importance of the material. To address this knowledge gap, a "dissolution" study, in vivo biokinetic study in a rodent model (1 MBq intratracheal instillation, 3-month follow-up) and associated state-of-the-art modelling were undertaken to derive dose coefficients for model tritiated steel particles. A committed effective dose coefficient for the inhalation of 3.3 × 10-12 Sv Bq-1 was evaluated for the particles, reflecting an activity median aerodynamic diameter (AMAD) of 13.3 µm, with the value for a reference AMAD for workers (5 µm) of 5.6 × 10-12 Sv Bq-1 that may be applied to occupational inhalation exposure to tritiated steel particles.
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Affiliation(s)
- Rachel Smith
- Radiation Chemicals and Environmental Hazards, UK Health Security Agency, Harwell Campus, Didcot OX11 0RQ, UK
- Correspondence: (R.S.); (E.B.)
| | - Michele Ellender
- Radiation Chemicals and Environmental Hazards, UK Health Security Agency, Harwell Campus, Didcot OX11 0RQ, UK
| | - Chang Guo
- Radiation Chemicals and Environmental Hazards, UK Health Security Agency, Harwell Campus, Didcot OX11 0RQ, UK
| | - Derek Hammond
- Radiation Chemicals and Environmental Hazards, UK Health Security Agency, Harwell Campus, Didcot OX11 0RQ, UK
| | - Adam Laycock
- Radiation Chemicals and Environmental Hazards, UK Health Security Agency, Harwell Campus, Didcot OX11 0RQ, UK
| | - Martin O. Leonard
- Radiation Chemicals and Environmental Hazards, UK Health Security Agency, Harwell Campus, Didcot OX11 0RQ, UK
| | - Matthew Wright
- Radiation Chemicals and Environmental Hazards, UK Health Security Agency, Harwell Campus, Didcot OX11 0RQ, UK
| | - Michael Davidson
- Radiation Chemicals and Environmental Hazards, UK Health Security Agency, Harwell Campus, Didcot OX11 0RQ, UK
| | - Véronique Malard
- Biosciences and Biotechnology Institute of Aix-Marseille (BIAM) (Aix-Marseille University, French Alternative Energies and Atomic Energy Commission (CEA), French National Centre for Scientific Research (CNRS)), 13108 Saint Paul-Lez-Durance, France
| | - Mickaël Payet
- Institute for Magnetic Fusion Research (IRFM), French Alternative Energies and Atomic Energy Commission (CEA), 13108 Saint-Paul-lez-Durance, France
| | - Christian Grisolia
- Institute for Magnetic Fusion Research (IRFM), French Alternative Energies and Atomic Energy Commission (CEA), 13108 Saint-Paul-lez-Durance, France
| | - Eric Blanchardon
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), 92260 Fontenay-aux-Roses, France
- Correspondence: (R.S.); (E.B.)
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Bull RK, Puncher M. MWDS-2016: THE SLOW DISSOLUTION RATE FOR PLUTONIUM NITRATE INTAKES AT THE MAYAK FACILITY. Radiat Prot Dosimetry 2019; 185:201-207. [PMID: 30668839 DOI: 10.1093/rpd/ncy296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 12/13/2018] [Accepted: 12/20/2018] [Indexed: 06/09/2023]
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.
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Affiliation(s)
| | - M Puncher
- Public Health England, Chilton, Didcot, Oxon, UK
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