Recent interest in using uranium mononitride (UN) as the fission core for accident tolerant nuclear fuels in the form of tristructural isotropic (TRISO) particle fuels has brought forth the importance of investigating different routes in synthesizing UN. Other than synthesizing UN, such investigations should also unveil potential pathways that could lead to the fabrication of high density UN; densities up to 95% theoretical density. Furthermore, the replacement of UO2 by UN in nuclear fuels has been considered because of UN's desirable chemical and physical properties such as high fissile metal density, high melting point, and high thermal conductivity compared to UO2. In this presentation, we discuss a synthetic route to UN in the form of microspheres via higher nitrides, especially uranium sesquinitride (U2N3). In this process, microspheres of carbon-incorporated UO2 or UO3 were first synthesized using an internal gelation process. These oxides were nitridized in N2 gas environment to form U2N3, which was then fully converted into UN. Chemical and physical characteristics such as phase purities, microstructure, and densities of higher nitrides as well as the mononitride will be discussed in this presentation.

Synthesis of uranium mononitride microspheres via higher uranium nitrides

248th National Meeting (2014)

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