Evaluation of neutron attenuation properties using helium-4 scintillation detector for dry cask inspection

• Published in: Nuclear Engineering and Technology
• Main Authors: Jihun Moon, Jisu Kim, Heejun Chung, Sung-Woo Kwak, Kyung Taek Lim
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2023
• Subjects: S670e; Helium-4 detector; dry cask; Neutron shielding; Neutron detection; Nuclear engineering. Atomic power; TK9001-9401; Arktis; Arktis*
• Online Access: https://doi.org/10.1016/j.net.2023.06.039; https://doaj.org/article/6fb5f4b80231485aac90e7540abf68d4

In this paper, we demonstrate the neutron attenuation of dry cask shielding materials using the S670e helium-4 detector manufactured by Arktis Radiation Ltd. In particular, two materials expected to be applied to the TN-32 dry cask manufactured by ORANO Korea and KORAD-21 by the Korea Radioactive Waste Agency (KORAD) were utilized. The measured neutron attenuation was compared with our Monte Carlo N-Particle Transport simulation results, and the difference is given as the root mean square (RMS). For the fast neutron case, a rapid decline in neutron counts was observed as a function of increasing material thickness, exhibiting an exponential relationship. The discrepancy between the experimentally acquired data and simulation results for the fast neutron was maintained within a 2.3% RMS. In contrast, the observed thermal neutron count demonstrated an initial rise, attained a maximum value, and exhibited an exponential decline as a function of increasing thickness. In particular, the discrepancy between the measured and simulated peak locations for thermal neutrons displayed an RMS deviation of approximately 17.3–22.4%. Finally, the results suggest that a minimum thickness of 5 cm for Li-6 is necessary to achieve a sufficiently significant cross-section, effectively capturing incoming thermal neutrons within the dry cask.