Abstracts and Available Papers Presented at the
2002 International RERTR Meeting

LOW ENRICHMENT Mo-99 TARGET DEVELOPMENT PROGRAM AT ANSTO

Therese M. Donlevy, Peter J. Anderson, David Beattie, Ben Braddock, Scott Fulton,
Robert Godfrey, Russell Law, Scott McNiven, Pertti Sirkka, Greg Storr, David Wassink, Alan Wong, Guan Yeoh

Australian Nuclear Science and Technology Organisation,
Private Mail Bag 1, Menai 2234, New South Wales, Australia

ABSTRACT

The Australian Nuclear Science and Technology Organisation (ANSTO, formerly AAEC) has been producing fission product Mo-99 in HIFAR, from the irradiation of Low Enrichment Uranium (LEU) UO₂ targets, for nearly thirty years. Over this period, the U-235 enrichment has been increased in stages, from natural to 1.8% 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 from target design through to chemical processing and waste management options. ANSTO has entered into a collaboration with Argonne National Laboratory (RERTR) to develop a target using uranium metal foil with U-235 enrichment of less than 20%

The initial focus has been to demonstrate use of LEU foil targets in HIFAR, using existing irradiation methodology.   The current effort focussed on designing a target assembly with optimised thermohydraulic characteristics to accommodate larger LEU foils to meet Mo-99 production needs.  The ultimate goal is to produce an LEU target suitable for use in the Replacement Research Reactor when it is commissioned in 2005.  This paper reports our activities on:

• The regulatory approval processes required in order to undertake irradiation of this new target
• Supporting calculations (neutronics, computational fluid dynamics) for safety submission.
• Design challenges and changes to prototype irradiation can
• Trial irradiation of LEU foil target in HIFAR
• Future target and rig development program at ANSTO

---

---