Sensitivity on the spatial assay for safeguards in the designed device

Tomographical assay technology was developed to simulate the sensitivity of detection of the replaced dummy and the fuel rods in spent fuel assembly for safeguard purposes. A remotely operated system was designed to assay the internal nuclear materials distribution. Monte Carlo code simulation was performed to find the optimum condition for accurate assay. From the sensitivity simulation, the reconstruction showed relatively less sensitivity at the center rod and an enhanced result at the outer fuel zone. Nevertheless, the missing rod and the fuel rod were reconstructed satisfactorily in the assembly.