Neutronic performance of fully ceramic microencapsulated of uranium oxycarbide and uranium nitride composite fuel in SMR

The existing commercial nuclear power plants (PWR and BWR) utilize the oxide fuels, i.e., UO2. This fuel selection is not questionable, where the safety and economy are the top priority in the nuclear industry. In this work, the potential advantages of microencapsulated fuels to System Integrated Modular Advanced Reactor SMART has been explored. The UN and UCO have been considered as the candidate fuel material for the SMART reactor. The detailed design and fuel assembly configurations with different fuel types of the SMART reactor have been investigated for criticality with depletion (burn up), fuel and moderator temperature coefficients, and power peaking factor using OpenMC. The fissile and fertile fuel elements with coated particles are embedded in graphite matrices. The results are presented with a review of attributes and potential benefits. The nitride fuel has an advantage of mechanical stability, enhanced thermal conductivity, and high fuel density compared to dioxide fuel (UO2). The melting point of standard fuel, UN, and UCO are similar. Thus, they have higher safety margins under NPP's operating conditions. Therefore, nitride (UN) and carbide (UCO) fuel types are more attractive than standard uranium oxides because they are safer and beneficial. The dioxide fuel (UO2) is considered as the reference and compared with candidate material. The neutronic assessment within SMART core specification examined the effective multiplication factor, thermal flux distribution, axial and radial power distribution, and power peaking factor at the beginning, and end of the fuel cycle. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study explores the potential advantages of microencapsulated fuels for the SMART reactor, investigating detailed designs and fuel assembly configurations with different fuel types, and their effects on criticality, burn up, and power peaking factor. The nitride (UN) and carbide (UCO) fuel types are considered safer and more beneficial compared to standard uranium oxides due to their mechanical stability, enhanced thermal conductivity, and high fuel density.