Fracture of Zircaloy-2 Cladding in Iodine Environment

The sensitivity coefficients of neutronic performance parameters in high-conversion LWR cells have been calculated by means of the SAINT code. In order to show the specific features of the sensitivity coefficients in the HCLWR cells, the differences between sensitivities were investigated for cells with different moderator to fuel volume ratios and different Pu enrichments. The burnup dependence of the sensitivities was also discussed with an emphasis on the effect of fission products on the cell parameters.

We have performed the sensitivity analysis for the PROTEUS cores. Group constants of main heavy nuclides were compared for the different cell calculational methods; SRAC and VIM, and the different cross section libraries; JENDL-2 and ENDF/B-IV. The effect of the differences in group constants was estimated for the cell parameters k _∞, reaction rate ratio and coolant void worth. The differences in the ²³⁸U capture and ²³⁹Pu fission group constants in the resolved and unresolved resonance range produced 0.3～1.0% change in k _∞ and 1～6% change in the coolant void worth. These effect was largely dependent on the coolant void fraction.