Comparison of calculation and measurements of reaction rates in the outer regions of superphenix

This paper brings together the results of two analyses of the Superphenix start-up measurements in the radial shield. Two different methods of calculation have been used based on SN transport theory (the PROPANE DO formulaire with the BISTRO code) and adjusted diffusion coefficients (the code SNAPSH using ADC method D). The PROPANE DO formulaire was found to give good agreement with the measured thermal flux both in the prediction of radial attenuation and in the reproduction of the axial profile. The ADC method was found to underestimate the attenuation. There were difficulties in reproducing the flux and neutron spectrum at the breeder/shield interface with both methods. This detailed comparison with measured values will assist in the formulation of recommended calculational routes for analysis of fast reactor shielding problems, an example of which has been the proposal of revised uncertainties for the PROPANE DO formulaire