Systematic analysis for the thermal stability assessment of 166Ho production using HANARO: An in silico study

Medical radioisotopes (RIs) are widely used in the diagnosis and treatment of tumors. Theranostic RIs, such as ¹³¹I, ¹⁶⁶Ho, ¹⁷⁷Lu, and ¹⁸⁶Re, are particularly notable for their ability to enable diagnosis and treatment simultaneously. Conducting irradiation tests using the High-flux Advanced Neutron Application Reactor (HANARO), a 30-MW multipurpose research reactor, enables the production of these medical RIs. Prior to irradiation tests, it is crucial to assess whether they affect the thermal stability of irradiated materials and the thermal-hydraulic safety of HANARO. This study systematically investigates the feasibility of ¹⁶⁶Ho production using the isotope production irradiation hole of HANARO, focusing on thermal stability. The nuclear heating rates of the RI production target and RI capsule are calculated using MCNP6, and the calculated nuclear heating rates are used for three-dimensional heat transfer analysis using COMSOL Multiphysics. Under the assumed conditions in this study, ¹⁶⁶Ho production did not compromise the thermal stability of the RI production target and RI capsule; consequently, the thermal-hydraulic safety criteria of HANARO could be satisfied. This study can serve as a valuable reference for evaluating the thermal stability of irradiated materials and the thermal-hydraulic safety of HANARO, which must be performed before irradiation tests using HANARO.