Local flow blockage analysis with checkerboard configuration in a wire wrapped fuel subassembly using the ASFRE code

Nishimura, Masahiro ; Fukano, Yoshitaka  

Deterministic evaluation of localflow blockage (LB) on the basis of state-of-the-art knowledge was performed using ASFRE code. In order to evaluate the effect of the realistic accidental condition, nominal power and flow rate were used for the analyses. Moreover the realistic blockage feature in the subassembly was newly adopted on the basis of existing experimental data which means LB in hound's-tooth pattern at a cross-section was assumed for the fuel subassemblies of wire spacer type. As the result, it was founds that the temperature increase in the downstream of LB was smaller than that in the past safety licensing because the flow pass is available around the blockage. And it was concluded that LB never lead to the large core damage from the evaluation results even if the blockage conditions beyond design criteria are assumed.