Study on a new design of Tehran Research Reactor for radionuclide production based on fast neutrons using MCNPX code

Highlights: • Medical isotope production using fast neutron flux is investigated. • Tehran Research Reactor is considered for radionuclide production. • New flux trap designs are proposed to enhance the fast neutron flux. • MCNPX code is employed to investigate the results. • The results all indicate a significant enhancement in production yield. - Abstract: The aim of this work is to increase the magnitude of the fast neutron flux inside the flux trap where radionuclides are produced. For this purpose, three new designs of the flux trap are proposed and the obtained fast and thermal neutron fluxes compared with each other. The first and second proposed designs were a sealed cube contained air and D₂O, respectively. The results of calculated production yield all indicated the superiority of the latter by a factor of 55% in comparison to the first proposed design. The third proposed design was based on changing the surrounding of the sealed cube by locating two fuel plates near that. In this case, the production yield increased up to 70%.