2006 International RERTR Meeting

Abstracts and Available Papers Presented at the Meeting

Design Study for a Low Enriched Uranium Core of the High Flux Isotope Reactor

R. T. Primm, III, R. J. Ellis, J. C. Gehin, and D. L. Moses
Oak Ridge National Laboratory
One Bethel Valley Road
Oak Ridge, Tennessee 37831-6399 - USA

ABSTRACT

Neutronics and thermal hydraulics studies for the High Flux Isotope Reactor (HFIR) show that low-enriched uranium (LEU) fuel elements can operate at equivalent power (85 megawatts-thermal) and core lifetime (26 days) as the current highly enriched uranium fuel elements. The low-enriched uranium (LEU) fuel is a metal alloy; uranium-10 weight percent molybdenum (U-10Mo) metal foil with radially "continuously graded" fuel meat thickness. However, the LEU fuel design results in a 15 percent reduction in peak thermal neutron flux in the beryllium reflector of the HFIR compared to the current HEU fuel. The LEU HFIR core weighs 30% more than the HEU core. A minimum U-10Mo foil thickness of 83.8 microns (3.3 mils) is required to compensate for power peaking in the LEU core although this value could be increased significantly without much penalty. The maximum U-10Mo foil thickness in the graded design is 457 microns (18 mils). For LEU dispersion fuel, the operating power for HFIR would be reduced considerably below 85 MW_th due to thermal considerations for an equivalent 26-day cycle.

 

---

---