Browsing by Author "Pandelus, SB"

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    Developing 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, T
    Recent 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.
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    Phase 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, RS
    The 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