Development of Uranium Enrichment Verification System for Nuclear Material Management in Korea

This study developed a field-deployable uranium enrichment verification system based on the infinite thickness method, as tailored to Korea’s nuclear materials and inspection conditions. The system, the Korea–Inspection Multi-Channel Analyzer (K-IMCA), integrates both sodium iodide (NaI) scintillation detectors and high-purity germanium (HPGe) detectors for rapid and accurate measurements, respectively. Custom sample holders and correction algorithms mitigate the effects of measurement geometry, gain variation, wall thickness, and matrix composition. Performance was evaluated using uranium dioxide (UO₂) pellets, fuel rods, and uranium hexafluoride (UF₆) cylinders, and benchmarked against the conventional IAEA’s Inspection Multi-Channel Analyzer (IMCA). For the UO₂ samples, the results remained within the acceptance range corresponding to three standard deviations, supporting their use in safeguards verification. In the UF₆ cylinder measurements, the NaI detectors showed large deviations; however, calibration constants improved consistency, indicating potential applicability under gamma-attenuated challenges. The HPGe detectors produced accurate enrichment results for low-enriched uranium and outperformed the IMCA, though limitations were observed in regions beyond the calibrated enrichment curve. These results demonstrate the K-IMCA’s enhanced applicability over the conventional IMCA and support its use as a reliable verification tool for nuclear material management in Korea.