UO2-Eu2O3 compound fuel fabrication via spark plasma sintering

UO2-based nuclear fuel containing integral fuel burnable absorbers (IFBA) is an economically and technically efficient solution for optimization of nuclear power reactors operation. The paper studies a new way to obtain compound UO2-Eu2O3 pellet fuel using an unconventional spark plasma sintering technology (SPS). Earlier unknown data on densification dynamics of (U,Eu)O-2 solid solution and its formation under SPS conditions is presented for IFBA content of 2 and 8 wt% introduced via ultra-sonication in the liquid phase. Structural changes in the fuel compositions depending on sintering temperature and IFBA content have been identified by the means of metallography and electron microscopy. A complex of measurements have been done to correlate materials microhardness (HV), compressive strength (sigma(cs)), and density (rho) with synthesis conditions. Pore and defect formation in the Eu2O3-rich regions of the UO2 ceramics is proved to be governed by Kirkendall effect, which was observed for conventional sintering approaches. Presented results are new and complement fundamental understanding the scope of opportunities unconventional SPS technique provides for nuclear power industry. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

The study investigates the use of unconventional spark plasma sintering technology (SPS) to produce composite UO2-Eu2O3 pellet fuel and presents data on densification dynamics and formation of (U,Eu)O-2 solid solution. Structural changes in the fuel compositions depending on sintering temperature and IFBA content were identified through metallography and electron microscopy. The formation of pores and defects in the Eu2O3-rich regions of UO2 ceramics is found to be controlled by the Kirkendall effect.