Browsing by Author "Martiniello, J"

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    Establishing a radioanalytical capability to support cyclotron decomissioning
    (South Pacific Environmental Radioactivity Association, 2022-11-20) Thiruvoth, S; Harrison, JJ; Bedwell-Wilson, J; Cunynghame, T; Martiniello, J; Mokhber-Shahin, L; Silitonga, A
    The 30 MeV cyclotron at the National Medical Cyclotron (NMC) ceased operations in October 2009 after producing medical isotopes for application in nuclear medicine for approximately 20 years. Upon its closure a process of decommissioning commenced. Initially, internal components that make up the cyclotron were removed, leaving behind the vault. The vault is predominantly constructed of concrete and steel reinforcements. Neutron activation of these materials produced radioisotopes that will need to be accurately identified and quantified to support decision making around storage and disposal options of these materials. This is a critical aspect of any cyclotron decommissioning project and has safety, environmental and economic implications. A capability to quantify typical radionuclides found in cyclotron materials is being developed at ANSTO. Cyclotron vault materials that may require assessment are concrete, steel and waters. Radionuclides of interest are typically beta- and gamma-emitting neutron activation products. Non-destructive, high resolution gamma spectrometry will be applied to quantify gamma emitting radionuclides such as 152Eu, 154Eu, 134Cs and 60Co. The complex matrix of some reactor materials will cause attenuation of gamma photons and empirical and/or theoretical corrections will be applied. Beta-emitting radionuclides will require a suite of destructive radioanalytical techniques designed to isolate and quantify beta-emitting radionuclides such as 59Fe and 55Fe. Gross beta counting will assist in identifying which samples will require destructive beta analysis. This presentation will outline the approach taken in identifying a sampling strategy and in the method development for non-destructive and destructive analysis and how this can support future cyclotron decommissioning needs of Australia and our region.
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    Establishing a radioanalytical capability to support reactor decommissioning
    (South Pacific Environmental Radioactivity Association, 2018-11-06) Harrison, JJ; Martiniello, J; Mokhber-Shahin, L; Rowling, B; Silitonga, AS; Thiruvoth, S; Vardenega, C; Van De Voorde, R; Wilsher, KL; Wong, HKY
    Australia’s first reactor, the 1O megawatt High Flux Australian Reactor (HIFAR) vi/as operated between 1958 and 2007. HIFAR was one of six DIDO reactors which were installed in the UK, Denmark, Germany and Australia. HIFAR was a multi-purpose reactor, initially used for nuclear material research followed by production of medical radioisotope; an: neutron diffraction experiments. Atter HIFAR was closed, a process of decommissioning commenced. Initially, internal components such as the fuel and heavy water (which acted as primary coolant and neutron moderator) were removed. Currently, HIFAR is in a “care and maintenance" phase whereby short-lived radionuclides can decay and non-radioactive equipment and instrumentation removed. Approximately 1OO research and power reactors have been decommissioned around the world including two of the DIDO class reactors at Harwell, UK and Risø, Denmark. ANSTO can draw on international experience as we as well as experience gained during decommissioning of its own 100 kilowatt Moata reactor in 2010. Accurate identification and quantification of radioactivity is a critical safety, environmental and economic aspect of any nuclear reactor decommissioning project as it supports decision making around long-term storage of disposal options of reactor materials as well as environmental assessment of the reactor site. A capability to quantify typical radionuclides found in reactor materials and environmental samples is being developed at ANSTO. Reactor materials that may require assessment include concrete, graphite and steel and environmental samples include soils and waters. Radionuclides of interest are predominantly beta- and gamma-emitting fission and activation products. Non—destructive, high resolution gamma spectrometry will be applied to quantify gamma emitting radionuclides such as 60Co, 66Zn, 133 Ba, 137Cs, 152 Eu, and 154Eu. The complex matrix of some reactor materials will cause attenuation of gamma photons and empirical and/or theoretical corrections will be applied. Beta-emitting radionuclides with weak or no gamma emission lines cannot be easily identified or quantified in solid materials using non-destructive techniques. This is due to attenuation of the beta particles, the nature of the beta emission spectrum and interferences from other beta- and gamma-emitting radionuclides. A suite of destructive radioanalytical techniques, designed to isolate and quantify beta-emitting radionuclides such as 3H, 14C, 36CI, 55Fe, 63Ni, 98Sr and 99Tc is being developed. This paper will present the timeline for development and the progress to date of this radioanalytical capability which will support the current and future decommissioning needs of Australia and our region.