Conceptual design of a high-performance hybrid object for applications of the fast neutron irradiation in MTRs

Fast neutron irradiation is one of the most strategic radiation applications of research reactors. Usually, it is performed around the reactor core containing lower neutron flux. In this paper, a hybrid object has been introduced and analyzed to enhance irradiating applications of the fast neutrons in the core of a Material Testing Reactor (MTR). The tool includes an old-type low-consumed HEU control fuel element, a dry channel, and a Cd filter. It is supposed to be installed at the internal neutron trap (D4 positions) of TRR core configuration. Calculating results are very promising for using the proposed tool to increase neutron fluxes, reduce thermal and epi-thermal neutron fluxes, and shift the neutron spectrum toward the fast neutron region (hardening effect) at the chosen irradiating location. Primary safety parameters are also checked and passed successfully. Furthermore, there are also some other presented safety items which must be checked carefully and conservatively in order to refabricate and install such a irradiating tool in an in-core location of a MTR.