Abstracts and Available Papers Presented at the
1997 International RERTR Meeting

CALCULATION OF MIXED HEU-LEU CORES FOR THE HOR
RESEARCH REACTOR WITH THE SCALE CODE SYSTEM

P.F.A. de Leege, H.P.M. Gibcus, J.E. Hoogenboom,
and J.W. de Vries

Interfaculty Reactor Institute (IRI), Delft University of Technology
Mekelweg 15, 2629 JB Delft, The Netherlands

ABSTRACT

The HOR reactor of Interfaculty Reactor Institute (IRI), Delft, The Netherlands, will be converted to use low enriched fuel (LEU) assemblies. As there are still many usable high enriched (HEU) fuel assemblies present, there will be a considerable reactor operation time with mixed cores with both HEU and LEU fuel assemblies. At IRI a comprehensive reactor physics code system and evaluated nuclear data is implemented for detailed core calculations. One of the backbones of the IRI code system is the well-known SCALE code system package. Full core calculations are performed with the diffusion theory code BOLD VENTURE, the nodal code SILWER, and the Monte Carlo code KENO Va. Results are displayed of a strategy from a HEU core to a mixed HEU-LEU core and eventually a LEU core.