Modeling and simulation of radiation profiles for spent fuel verification using OFPS in wet storage pools

Optical Fiber radiation Probe System (OFPS) is a verification equipment for physical inventory verification (PIV) of spent fuel bundles in the wet storage pools. In this study, a Monte Carlo simulation method using the ORIGEN code and Geant4 toolkit to generate the radiation profile for PIV was investigated to evaluate the performance of the OFPS. (1) The radioactivity of spent fuel bundles was calculated using ORIGEN code, (2) the wet storage pool environment was modeled using Geant4 simulations, and the contribution of each bundle to the detector signal was calculated. (3) The radiation profiles for PIV were generated using both data sets. The generated profile was compared to the experimental profile and demonstrated a close match. The proposed simulation method is expected to enable the prediction of OFPS measurement results and evaluate the performance of the OFPS.