Design rules for industrial-scale sintering of UB4-UBC composites with high uranium density

TL;DR

This paper presents scalable synthesis, structural analysis, and oxidation behavior of UB4-UBC composites, highlighting their potential as high-density, accident-tolerant nuclear fuel materials.

Contribution

It introduces an industrially scalable method for producing uranium boride composites and analyzes their high-temperature stability and oxidation properties.

Findings

UB4-UBC composites have higher uranium loading than monolithic UB4.

The composites show promising oxidation resistance at high temperatures.

In situ SXRD reveals structural evolution during high-temperature exposure.

Abstract

Uranium borides are promising candidate fuel forms for use in advanced nuclear reactors due to their high thermal conductivity and potential for dual use as both fuel and burnable absorber materials. In this work, uranium tetraboride (UB$_4$) and uranium monoboroncarbide (UBC) composites were synthesized using an industrially scalable borocarbothermic reduction method. The high-temperature structural evolution of the as-synthesized borides was investigated using in situ synchrotron X-ray diffraction (SXRD). The oxidation behavior was further characterized using a combination of SXRD and thermogravimetric analysis (TGA), allowing direct comparison with other potential accident-tolerant fuels such as UB$_2$, U$_3$Si$_2$, UC, and UN. The UB$_4$-UBC composite shows higher uranium loading than monolithic UB$_4$ and demonstrates promising oxidation behavior at elevated temperature, pointing to its potential as an improved uranium boride-based fuel form.