Abstracts and Available Papers Presented at the
1999 International RERTR Meeting

ALTERNATIVE LEU DESIGNS FOR THE FRM-II
 WITH POWER LEVELS OF 20-22 MW*

N. A. Hanan, R. S. Smith, and J. E. Matos
Argonne National Laboratory
Argonne, Illinois 60439-4815 USA

ABSTRACT

Alternative LEU Designs for the FRM-II have been developed by the RERTR Program at Argonne National Laboratory (ANL) at the request of an FRM-II Expert Commission established by the German Federal Government in January 1999 to evaluate the options for using LEU fuel instead of HEU fuel in cores with power levels of 20 MW. The ANL designs would use the same building structure and maintain as many of the HEU design features as practical. The range of potential LEU fuels was expanded from previous studies to include already-tested silicide fuels with uranium densities up to 6.7 g/cm³ and the new U-Mo fuels that show excellent prospects for achieving uranium densities in the 8-9 g/cm³ range. For each of the LEU cores, the design parameters were chosen to match the 50 day cycle length of the HEU core and to maximize the thermal neutron flux in the Cold Neutron Source and beam tubes. The studies concluded that an LEU core with a diameter of about 29 cm instead of 24 cm in HEU design and operating at a power level of 20 MW would have thermal neutron fluxes that are 0.85-0.86 times that of the HEU design in the Cold Neutron Source. With a potential future upgrade to a power of 22 MW, this ratio would increase to 0.92-0.93.

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