Browsing by Author "Vittorio, D"
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- ItemConverting HIFAR to low enriched uranium fuel(International Atomic Energy Agency, 2007-11-07) Storr, GJ; Vittorio, D; Hall, RThe 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 The LEU fuel was procured from Risoe National Laboratory in Denmark, was originally made for use in the DR3 reactor, and was modified to be compatible with HIFAR.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
- ItemOPAL Reactor commissioning and operations planning(International Group On Research Reactors, 2005-09-12) Vittorio, D; De Lorenzo, NANSTO's new reactor facility, OPAL, is a multipurpose 20 MW open pool reactor fuelled by 16 low enriched uranium fuel assemblies. INVAP S.E., Argentina, and its Australian subcontractors are responsible for the design, construction and commissioning of the OPAL reactor. Concrete pouring commenced in November 2002 and Commissioning is scheduled to commence in late 2005. In order to support the commissioning process, a systematic inspection and testing program has been implemented to demonstrate the performance of all systems, particularly those with a safety function. Therefore, tests of the systems and components of the OPAL reactor are rigorously performed during the installation, pre-commissioning and commissioning stages. Testing is planned and organised in a logical sequence aimed to demonstrate individual system performance and subsequent integration with other plant systems. In particular, the Commissioning Stages involve a comprehensive series of system integration, fuel loading, power ascension and full power tests, in full accordance with IAEA recommendations. These tests are performed with the application of Commissioning Procedures as issued by INVAP and reviewed by ANSTO in order to ensure completeness and suitability. A Commissioning Plan defines and states the framework for all of the Commissioning activities and four specific plans (named as Stage A/B1/B2/C Specific Commissioning Plan) detail the individual stage. This paper provides a summary of the contents of these Plans and an overview of the operational arrangements that will be implemented in order to ensure safe and efficient commissioning of the OPAL Reactor as well as the further transition to Routine Operation arrangements.
- ItemThe OPAL Research Reactor(Amsterdam: Elsevier, 2021) Vittorio, D; Summerfield, MVThe major nuclear research and development activities in Australia, including the operation of infrastructure and businesses associated with these activities, are conducted by the Australian Nuclear Science and Technology Organisation (ANSTO). ANSTO’s current operations are primarily based around large-scale scientific infrastructure supporting the production of radio-isotopes, particularly for health and medicine and the safe and secure management of radioactive wastes. The most important piece of nuclear infrastructure in Australia is the OPAL research reactor, which is multi-purpose by design with its main applications being neutron beams for research and irradiation of many different materials, some of which allow manufacture of radioisotopes for health and medicine. OPAL is a key part of the supply chain for the manufacture of radioisotopes and radiopharmaceuticals for the health sector and other radioisotopes for a number of other industrial and research sectors. © 2023 Elsevier B.V.
- ItemPlanning for final operation of the HIFAR Reactor(International Group On Research Reactors, 2005-09-12) Vittorio, D; Hall, RThe Australian Nuclear Science and Technology Organisation (ANSTO) has operated the HIFAR research reactor since 1958. Construction of the new OPAL research reactor commenced in 2002 and commissioning is due to commence in late 2005. ANSTO faces a number of challenges during the final year of HIFAR operation and dual operation of HIFAR and the OPAL reactor. These challenges include plant staffing for the dual operation phase, regulatory expectations, HIFAR’s ageing plant and fuel supplies. HIFAR operation has been extended by the procurement of a number of LEU silicide fuel elements purchased from RISO, Denmark, and the implementation of a program to convert to a LEU fuelled core. This will enable continuing operation of HIFAR during the commissioning and early operation phases of the OPAL reactor. A decommissioning plan will be implemented following the final shutdown of HIFAR. This paper discusses the challenges that face ANSTO during the operational transition from HIFAR to the OPAL reactor.
- ItemTraining and qualification of reactor operating personnel(International Atomic Energy Agency, 2007-11-07) Kulak, R; Walsh, P; Vittorio, DThe training and qualification of OPAL Reactor Operations personnel is based on IAEA guidelines which recommend a Systematic approach to training. This involves performance and task based training which when used correctly establishes and maintains the competency and qualifications of staff. OPAL operator training is broadly grouped into classroom theory training, simulator training and practical plant training. The training is carefully structured to ensure that the selected candidate fulfils not only his personal ambitions but also the organisations needs. Our discussions will outline this approach. © The Authors
- ItemUtilisation of the OPAL Research Reactor(European Research Reactor Conference, RRFM, 2019-03-24) Fraihat, R; Vittorio, DThe OPAL Research Reactor incorporates a number of irradiation facilities designed to accommodate various physical target sizes, flux levels and irradiation times. Since the commissioning of the OPAL Research Reactor in 2006, the utilisation of these irradiation facilities has steadily increased based on the requests from stakeholders and specific user groups. This increase in utilisation has required greater awareness of forecast demand and improved integration between the reactors digital operating systems and the enterprise wide management systems. This paper provides an overview of the OPAL irradiation facilities and how they fit in with the overall ANSTO processes together with a discussion about how forecast demand and improved integration have been implemented.