Feasibility of radioisotope production by neutron spectral selection: Mathematical and computational approaches

Abstract

The main goal is to investigate the theoretical feasibility of producing neutron-rich radioisotopes in a Selective Spectral Resonant Selector (RSS), targeting radiative neutron capture reactions in precursor nuclides. The reaction rates of the precursor nuclides and contaminants were evaluated and converted into normalized activity per unit mass, assuming an arbitrary input intensity. Two distinct RSS MB and MR configurations were considered in the problem-solving approach. RSS MB with a neutron source of 10⁸ n.s⁻¹, 3d exposure time, provides the specific activities (MB.g⁻¹) of close to 896 to ¹⁵³Sm; 306, ¹⁷⁷Lu; 804, ¹⁸⁸Re; 1190 ¹⁶⁶Ho; while RSS MR provides 36 to ¹⁷⁷Lu; 10, ¹⁶⁹Yb; 135, ¹⁹²Ir, as example. As a benchmark, the comparative performance of RSS and traditional radioisotope production was assessed based on an activation potential parameter η, providing values 3.2M, 1.1k, 620 for ¹⁵³Sm,¹⁷⁷Lu,¹⁸⁸Re, respectively, with RSS MR achieving significantly higher potential compared to nuclear reactors. The reaction ¹⁸⁷Re(n,γ)¹⁸⁸Re in a natural abundant target cannot be used in a nuclear reactor due to large contamination; however, RSS MR demonstrates the capability to produce ¹⁸⁸Re with 60 times the activity of the contaminant ¹⁸⁶Re. The specific activities and benchmark parameters from different radionuclides demonstrates the effectiveness of the RSS for radioisotope production.