2006 International RERTR Meeting

Abstracts and Available Papers Presented at the Meeting

CONVERSION OF AUSTRALIA'S HIFAR RESEARCH REACTOR TO LEU FUEL

G. Storr, R. Hall and D. Vittorio
Reactor Operations Division
Australian Nuclear Science and Technology Organisation (ANSTO)
PMB 1 Menai, NSW 2234
Australia

ABSTRACT

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 The LEU fuel was procured from RISO National Laboratory in Denmark, was originally made for use in the DR3 reactor, and was modified to be compatible with HIFAR.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, provides 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 that have been studied for LEU fuel reanalyse operational and accident conditions that have been previously analysed for HEU fuel. In most cases the conclusions provided in each analysis demonstrate there is little difference in behaviour between HEU fuel and LEU fuel in HIFAR under operational and accident conditions. However, there is one significant difference between HEU and LEU fuel as it is 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 presents results from the measurement program undertaken during the conversion to show that the measured parameters were consistent with those calculated for the safety case. HIFAR is now operating safely with a full LEU core and is expected to do so until its final closure, planned for early 2007.

 

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