A New Tone'S Method In Apollo3 And Its Application To ZPPR Benchmarks

International audienceThis paper presents a newly developed resonance self-shielding method based on Tone's method in APOLLO3 for fast reactor calculations. The new method is based on the simplified models, the narrow resonance approximation for the slowing down source and Tone's approximation for group collision probability matrix. It utilizes the mathematical probability tables as quadrature formulas in calculating the effective cross sections. Numerical results for the ZPPR drawer calculations show that, in case of the double column fuel drawer, Tone's method gives equivalent precision to the subgroup method while reducing largely the total number of the collision probability matrix calculations hence the CPU time. In case of the single column fuel drawer with presence of a uranium metal material, Tone's method obtains less precise results than those of the subgroup method due to less precise heterogeneous-homogeneous equivalence