ASNC upgrade for nuclear material accountancy of ACPF

• Published in: Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment Accelerators, spectrometers, detectors and associated equipment, 2018-02, Vol.880, p.58-66
• Main Authors: Seo, Hee, Ahn, Seong-Kyu, Lee, Chaehun, Oh, Jong-Myeong, Yoon, Seonkwang
• Format: Article
• Language: English
• Subjects: Neutron detector; Non-destructive assay; Nuclear material accountancy; Safeguards
• ISSN: 0168-9002; 1872-9576
• DOI: 10.1016/j.nima.2017.10.045

A safeguards neutron coincidence counter for nuclear material accountancy of the Advanced spent-fuel Conditioning Process Facility (ACPF), known as the ACP Safeguards Neutron Counter (ASNC), was upgraded to improve its remote-handling and maintenance capabilities. Based on the results of the previous design study, the neutron counter was completely rebuilt, and various detector parameters for neutron coincidence counting (i.e., high-voltage plateau, efficiency profile, dead time, die-away time, gate length, doubles gate fraction, and stability) were experimentally determined. The measurement data showed good agreement with the MCNP simulation results. To the best of the authors’ knowledge, the ASNC is the only safeguards neutron coincidence counter in the world that is installed and operated in a hot-cell. The final goals to be achieved were (1) to evaluate the uncertainty level of the ASNC in nuclear material accountancy of the process materials of the oxide-reduction process for spent fuels and (2) to evaluate the applicability of the neutron coincidence counting technique within a strong radiation field (e.g., in a hot-cell environment). •The ACP safeguards neutron counter (ASNC) for nuclear material accountancy of the ACPF was upgraded.•The remote-handling and maintenance capabilities for hot-cell operation were improved.•Various parameters were measured and determined for detector characterization.