Characterisation of anthropogenic radioactive particles from former weapon test sites in Australia

Former nuclear test sites on Australian territories such as those at Maralinga and the Montebello islands have been remediated to varying extents but wide-spread radioactivity still remains. Fission and neutron-activation products at the test sites have been decaying over time but long-lived radioisotopes such as uranium and plutonium persist within the environment, predominantly in the form of discrete particles. These particles vary widely in composition depending upon the detonation characteristics and local geology, and are widely dispersed around each site. Radioactive particles are the dominant form of radionuclides at the former test sites and the future distribution of radioactive contaminants in the environment at these sites is largely dependent upon their fate and behaviour. The weathering of particles in the environment and the potential release of the radioactivity they contain is influenced by a range of factors including particle morphology, elemental composition and chemical form, and the prevailing environmental conditions. Radioactive particles have been isolated from soils and sediments from Australian test sites and characterised using photostimulated luminescence (PSL)-autoradiography, scanning electron microscopy energy dispersive X-ray spectroscopy (SEM-EDS), Synchrotron X-ray fluorescence microscopy (XFM) and particle-induced X-ray emission (PIXE). The characteristics of the particles and potential implications for their long term fate will be discussed in the context of the techniques applied and the environments in which the particles were found.

Keywords

Nuclear test sites, Nuclear weapons, Australia, Radioactivity, Fission, Environment, Particles, Soils, Sediments, PIXE analysis

Citation

Young, E., Johansen, M., Child, D. P., Hotchkis, M. A. C., Howell, N., Pastuovic, Z., Howard, D. L., Palmer, N., & Davis, J. (2018). Characterisation of anthropogenic radioactive particles from former weapon test sites in Australia. Paper presented to the SPERA Conference 2018, "Bringing environmental radioactivity research to Western Australia, Perth, Western Australia, 6 - 9 November 2018, (pp. 55).