Computational investigation of Tehran research reactor graphite reflector replacement with Be, BeO or D2O and its impacts on thermal neutron flux enhancement

Abstract

Thermal neutron flux enhancement is an essential objective to achieve more radioisotope production in the research reactors. Here, the effect of graphite reflector replacement with other customary reflectors on thermal neutron flux enhancement of Tehran Research Reactor (TRR) core has been investigated. The core is modelled using Monte Carlo-based code with the graphite routine reflector and with Be, BeO, and D2O reflectors. The calculations showed that the reflector replacement could result in a little enhancement of thermal neutron flux while beryllium oxide is suggested as the most efficient material (about 2.78% on average per channel). In addition, instead of total reflector conversion, application of some dimensionally optimised BeO blocks located around the irradiation boxes increases the thermal neutron flux up to 2.62%. Moreover, this study demonstrates that compacting the core could significantly enhance the thermal neutron flux up to 58% that is noticeably more than the reflector conversion effect.