Combustível composto avançado UO2-UN com condutividade térmica melhorada e alta densidade

Abstract

Today, many efforts focus on ceramic fuels that can replace standard uranium dioxide (UO2). In this context, uranium nitride (UN) could replace UO2 used in light water reactors (LWRs). The UN fuel has a higher uranium density and better thermal conductivity than UO2. The drawback of UN is a lower oxidation resistance in contact with the water. Regardless, adding a compound that acts as a protective barrier against nitride oxidation, such as ZrN, U3Si2, and UO2, could reduce water oxidation. Early, UO2–UN composites were fabricated by hot pressing UO2–UN powder mixtures within 1300 °C–1590 °C. The manufacturing process adopted for the fuel pellet fabrication changed to the spark plasma sintering (SPS) method. Using SPS can avoid the exceptional resistance to producing a perfect microstructure and the high costs associated with 15N enrichment. The composite fuel suggested is UN-10% U3Si5 verified with FRAPCON code.