Validation Study on SFR Core Bowing Codes using Joyo Ex-Core Experiment Data: Multiple Duct Bowing Benchmark

Assembly core bowing and core radial expansion are important features in sodium-cooled fast reactors due to the sensitivity of the reactivity feedbacks to small displacements of the active fuel in the core.These negative feedbacks are especially important during abnormal transients such as unprotected transient overpower and unprotected loss of flow.To characterize the negative feedback effects, accurate prediction of the fuel assembly displacement is important.The objective of this study is to increase confidence in the estimation of core duct bowing using multi-duct thermal bowing experiment data.Through a bilateral United States -Japan collaboration, ANL, JAEA, and CRIEPI performed thermal bowing analysis of their core bowing codes comparing the results to validation data of multi-duct thermal bowing and contact force measurements.Comparisons of the analysis results with the experimental measurements showed the core bowing codes were able to reasonably predict the assembly bowing displacement values and contact at the load pads.