Experimental validation of a physics-based CRUD growth model using dedicated PWR loop tests

The model previously developed to predict CRUD growth during the operation of PWRs was validated through the benchmark study for CRUD loop experiments. Because of the difference in the operation conditions between the CRUD loop and PWRs, there is a difference in the growth mechanism of the CRUD layer. Two CRUD loop experiments conducted in the UNIST and KAERI were selected as benchmark cases in this benchmark study. The model predicted similar growth behavior for the porous CRUD layer under the UNIST loop operating conditions, although there was a slight mismatch in the axial distribution and the deposition of the dense CRUD layer, which formed after the loop operation. In contrast, the model overestimated CRUD growth in the seven KAERI loop experiments when using the default sticking probability. A sensitivity study showed that reducing the sticking probability yielded better agreement with all experimental measurements. The uncertainties in the benchmark study were analyzed in terms of differences in operational conditions and CRUD growth mechanisms. This study aimed to identify the limitations of loop-based benchmarking and to suggest future research directions. These insights can be used to improve the detail and accuracy of CRUD growth predictions under both PWR and loop operation conditions.