Neutron-Induced Medical Radioisotope Production in a Conceptual Accelerator-Driven System, Fueled with Uranium Carbide

Abstract

In this study, the medical radioisotope production performance of a conceptual accelerator-driven system is investigated. Lead-bismuth eutectic is used as target material. The fuel core of the considered accelerator-driven system is divided into ten subzones, loaded with uranium carbide and various isotopes (isotopes of copper, gold, cobalt, holmium, rhenium, scandium, and thulium) and cooled with light water. As is known, light water is an effective moderator of neutrons as well as a good coolant. The fuel and the isotopes are separately placed as cylindrical rods with a cladding of carbon composite. The volume fractions of fuel, isotope, cladding and coolant are selected as 25%, 35%, 10% and 30%, respectively. The copper rods are placed into the first five subzones due to the fact that copper isotopes have low capture cross-section. In the case of the each radioisotope production, one of the other considered isotopes that have higher capture cross-section are placed into the following five subzones for optimization of fission, fissile breeding and radioisotope production. The graphite zone is located around the fuel core to reflect the escaping neutrons. Boron carbide (B4C) is used as shielding material. In order to produce more neutrons (about 25-30 neutrons per 1 GeV proton), the target is irradiated with a continuous beam of 1 GeV protons. All neutronic computations have been performed with the high-energy Monte Carlo N-Particle Transport Code using the LA150 data library. The neutronic results obtained from these calculations show that the examined accelerator-driven system has a high neutronic capability, in terms of production of thermal power, fissile fuels, and medical radioisotopes.