Using a coupled dispersion model to estimate depletion of a tritium oxide plume by a forest

Journal Article · Sat May 30 00:00:00 EDT 2020 · Journal of Environmental Radioactivity

DOI:https://doi.org/10.1016/j.jenvrad.2020.106316· OSTI ID:1632837

Viner, Brian J. ^[1]; Goodlove, Sydney ^[1]

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1. Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

Tritium processing facilities may release tritium oxide (HTO) to the atmosphere which poses potential health risks to exposed co-located workers and to offsite individuals. Most radiological consequence analyses determine HTO dose by applying Gaussian plume models to simulate the transport of HTO. Within these models, deposition velocity is used to assess the sum of all deposition processes acting on the plume. While this may account for vegetative and soil uptake or respiration processes, it may currently lack inclusion of the complex interactions within heterogeneous forested environments. In this complex morphology, dispersion patterns are significantly altered by changing flow regimes above and below the forest canopy and by the transfer of plume material across the canopy boundary. To determine the effects of a heterogeneous forest canopy on an airborne HTO plume, a Gaussian plume model coupled with an advection-diffusion plume model was applied to estimate transport in the free atmosphere above the forest and within the forest canopy and understory. During 2012, wind speed and wind direction measurements taken at 5 heights, ranging from 2-m to 28-m, on an instrumented meteorological tower located in a loblolly pine forest at the Department of Energy (DOE) Savannah River Site (SRS), near Aiken, SC. From these measurements, model predictions were made over a full spectrum of meteorological conditions. Deposition and resuspension velocities were calculated based on the model-predicted flux of plume material across the top of the forest canopy. Additionally, net deposition velocity of the plume material was calculated as the difference between the deposition and resuspension velocities. The 1st and 5th percentile net deposition velocities were estimated to be 0.7 cm s-1 and 1.2 cm s-1, respectively.

• Research Organization: Savannah River National Lab (SRNL), Aiken, SC (United States); Savannah River Site (SRS), Aiken, SC (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA)
• Grant/Contract Number: AC09-08SR22470
• OSTI ID: 1632837
• Alternate ID(s): OSTI ID: 1631348
• Report Number(s): SRNS-STI--2020-00200
• Journal Information: Journal of Environmental Radioactivity, Journal Name: Journal of Environmental Radioactivity Journal Issue: C Vol. 220-221; ISSN 0265-931X
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.