Browsing by Author "Pandelus, SB"
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- ItemDeveloping international radiological risk assessment tools for Australian arid environments(South Pacific Environmental Radioactivity Association, 2018-11-06) Popelka-Filcoff, RS; Pring, A; Pandelus, SB; Johns, SM; Tucker, W; Rossouw, D; Lenehan, CE; Hondros, J; Hirth, GA; Carpenter, JG; Johansen, MP; Payne, TE; Roberts, M; Levingstone, K; Tuft, K; Duff, TRecent international and Australian regulatory guidance llCRP 108 and ARRANSA Env. Prot. Guide, 2015) has increased the need for effective tools to assess radiological impacts in the environment. The existing internationally accepted methods and models are generally based on data collected in the northern hemisphere and there is a recognised lack of southern hemisphere data, particularly from Australia. When applying the models and methods in Australia, acknowledgement of this lack of data is required which tends to undermine public and regulatory confidence in the assessment. Development of an Australian-specific data set is essential to a better understanding and more credible environmental impact assessment process. In addition, decision-making by operators and regulatory authorities will be based on more relevant local information This presentation describes a collaborative project between university, government and industry researchers and a national industry funding body, aimed at developing a more complete understanding of radiological uptake of native flora and fauna in arid Australian environments. The presentation will cover the framework and sampling and analysis approaches from arid environments, and how these fit into international practice. lnitial data and concentration ratios from analysis of Dodonaea viscosa and Acacia ligulata, rabbits and feral cats and corresponding soil will be presented. Analytical methods include high-resolution gamma spectroscopy with low limits of detection, alpha spectroscopy, elemental analysis by inductively coupled plasma mass spectrometry, scanning electron microscopy. ant"; 3."; 5 Novel approaches to data collection and analysis protocols are used, which form the basis of the databases use: :. i"e internationally accepted models and comparison to extant studies. The project lays the infrastructure towards an effective Australian intenface with existing tools (e.g. ERICA) and assessment for extended long-term studies for industry and regulators. The results of this project build a foundation for environmental radionuclide assessment for Australia's specific climate and species, and build a framework for a comprehensive Australian context and understanding of radionuciides and their concentration ratios as well as towards screening levels which may vary depending on location and species. This project has an industry-wide impact in the generation of robust data sets towards modelling in arid environments.
- ItemPhase analysis of Australian uranium ore concentrates determined by variable temperature synchrotron powder x-ray diffraction(American Chemical Society, 2021-07-22) Pandelus, SB; Kennedy, BJ; Murphy, GL; Brand, HEA; Keegan, EA; Pring, A; Popelka-Filcoff, RSThe chemical speciation of uranium oxides is sensitive to the provenance of the samples and their storage conditions. Here, we use diffraction methods to characterize the phases found in three aged (>10 years) uranium ore concentrates of different origins as well as in situ analysis of the thermally induced structural transitions of these materials. The structures of the crystalline phases found in the three samples have been refined, using high-resolution synchrotron X-ray diffraction data. Rietveld analysis of the samples from the Olympic Dam and Ranger uranium mines has revealed the presence of crystalline α-UO2(OH)2, together with metaschoepite (UO2)4O(OH)6·5H2O, in the aged U3O8 samples, and it is speculated that this forms as a consequence of the corrosion of U3O8 in the presence of metaschoepite. The third sample, from the Beverley uranium mine, contains the peroxide [UO2(η2-O2)(H2O)2] (metastudtite) together with α-UO2(OH)2 and metaschoepite. A core–shell model is proposed to account for the broadening of the diffraction peaks of the U3O8 evident in the samples. © 2021 American Chemical Society
- ItemRadionuclide uptake mechanisms by native flora in the vicinity of uranium mines in arid South Australia(ICRP, 2019-11-17) Pandelus, SB; Pring, A; Johansen, MP; Payne, TE; Stopic, A; Spooner, NA; Kalnins, GAG; Popelka-Filcoff, RSEnvironmental risk assessments for radiological impacts follow internationally accepted methods including use of the Environmental Risk from Ionising Contaminants: Assessment and Management (ERICA) tool. Concentration ratios (ratio of radionuclides in an organism to that of its host soil/water- CR) are an essential input for these models. However, the available international input data are primarily from temperate Europe and North America, and may not apply in arid conditions. Previous studies have shown that Australian native species accumulate radionuclides from their environment differently when compared to similar species from other climates. This research aims to develop a concentration ratio dataset relevant for U and Th series radionuclides in arid and semi-arid conditions. Olympic Dam, operated by BHP, is a large copper, uranium, gold and silver producer in South Australia, and utilises underground mining, with the ore being processed on site. To examine radionuclide uptake mechanisms by native flora, samples of flora and adjacent soil have been collected at Olympic Dam. Analyses of flora and soil samples included gamma-ray spectroscopy, neutron activation analysis, alpha-particle spectroscopy and inductively coupled plasma mass spectrometry (ICP-MS). Alternative analytical methods have been incorporated including alpha track analysis for flora samples. Alpha track analysis uses a nuclear emulsion gel layer applied to the individual leaf sample. Analysis of the gel is used to identify radionuclide accumulation and spatially-resolve its location within structures of the leaves. Soil from the surface to 10 cm below the surface was analysed by ICP-MS. Results show a gradient of uranium concentration from 4 ppm at the surface to 0.5 ppm at a depth of 10 cm. The soil depth profile data show that the most probable mechanism of radionuclide transport is airborne and therefore any potential uptake into flora is influenced by the depositional effects on the soil surface. Overall this research provides a better understanding of the behaviour of radionuclides in an arid environment and provides data on the mechanisms of radionuclide uptake in flora. It augments existing international data for use in models in Australia and other localities with similar arid environments.