Browsing by Author "Storr, GJ"

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    Converting HIFAR to low enriched uranium fuel
    (International Atomic Energy Agency, 2007-11-07) Storr, GJ; Vittorio, D; Hall, R
    The Australian Nuclear Science and Technology Organisation (ANSTO) began operating the High Flux Australian Reactor (HIFAR) in 1958, a DIDO-class research reactor operated at a thermal power of 10 MW. On 30th January 2007, after more than 49 years of successful and safe operation HIFAR was finally shutdown. Since that time all the fuel has been successfully removed from the reactor containment building. HIFAR was primarily used for neutron scattering science, service irradiations and isotope production. Over the nearly 50-year operating life of HIFAR a variety of fuel designs have been used. After the 1970s fuel enrichment was reduced in stages from over 90 percent to 19.75% in 2006. The reactor core consisted of 25 fuel elements with uranium-aluminium alloy fuel sections, arranged in concentric tubes. HIFAR was moderated and cooled by heavy water, and the coolant contained within an aluminium tank, which in turn was surrounded by a graphite reflector and concrete biological shielding. Reactor control and shutdown were achieved with six europium tipped cadmium control blades, which moved as a bank between the rows of fuel elements. Two cadmium shutdown rods provided additional shutdown capacity. In May 2006 the HIFAR reactor was fully converted to Low Enriched Uranium fuel. The conversion commenced in October 2004. The LEU fuel was procured from Risoe National Laboratory in Denmark, was originally made for use in the DR3 reactor, and was modified to be compatible with HIFAR. This type of fuel was used safely in DR3 before its closure. A safety analysis report for the approval and use of the LEU fuel which was prepared well in advance of loading the fuel into HIFAR, provided detailed analyses of issues important to reactor and general fuel safety, including, criticality safety outside the reactor, reactor physics, eversafe times, thermal hydraulics and accident analyses. Many of the issues studied for LEU fuel reanalysed operational and accident conditions that had been previously analysed for HEU fuel. In most cases the conclusions provided in each analysis demonstrated there was little difference in behaviour between HEU fuel and LEU fuel in HIFAR under operational and accident conditions. However, there was one significant difference between HEU and LEU fuel as it was shown that in general eversafe times for LEU fuel are greater than for HEU fuel. Consequently, procedures were modified for some operations to ensure compliance with safe heat limits. The paper will present the process undertaken for the conversion of HIFAR, including the development of the safety case, requirements for regulatory approvals, and results from the conversion program. © The Authors
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    Low enrichment Mo-99 target development program at ANSTO
    (Argonne National Laboratory, 2002-11) Donlevy, TM; Anderson, PJ; Storr, GJ; Yeoh, G; Beattie, D; Deura, M; Wassink, D; Braddock, B; Chant, W
    The Australian Nuclear Science and Technology Organisation (ANSTO, formerly AAEC) has been producing fission product Mo-99 in HIFAR, from the irradiation of LEU UO2 targets, for nearly thirty years. Over this period, the U-235 enrichment has been increased in stages, from natural to 1.8% then finally to 2.2%. The decision to provide Australia with a replacement research reactor (RRR) for HIFAR has created an ideal opportunity to review and improve the current Mo-99 production process, right from target design through to chemical processing and waste management. The major focus at this point in time is the development of a LEU target, initially suitable for irradiation in HIFAR and, with subsequent modification, suitable for irradiation in the RRR. We have entered into collaboration with Argonne National Laboratory (RERTR) to develop such a target using uranium metal foil with U-235 enrichment of less than 20%. The first trial irradiation of this target is planned in December 2000 and it will be processed using the current Mo-99 production process at ANSTO. The review of this trial will determine the program for further irradiations.
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    Molten fuel-coolant interactions resulting from power transients in aluminium plate/water moderated reactors.
    (Australian Nuclear Science and Technology Organisation, 1989) Storr, GJ
    The behaviour of two reactors SL1 and SPERT D12 which underwent fast nuclear power transients prior to core destruction by a molten fuel-coolant interaction (MFCI) has been analysed and the results compared with measured data. The calculated spatial melt distribution and the mechanical work done during the events leads to high (approx 250 kJ/kg) conversion efficiencies for this type of interaction when compared with molten drop experiments. A simple model for the steam explosion using static thermodynamic properties of high temperature and pressure steam is used to calculate the dynamics of the reactors following the MFCI.
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    The Opal Research Reactor - its status, achievements and future
    (Australian Nuclear Association, 2011-10-07) Storr, GJ
    Not available. Physical copy available in ANSTO Library at 621.48/17
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    Performance indicators for research reactors
    (International Group On Research Reactors, 2010-09-19) Storr, GJ; Summerfield, MW
    Not available