Examination of HIP for production of high density UN kernels

Abstract

Depleted uranium nitride (UN) kernels with diameters ranging from 420 to 858 microns and theoretical densities between 87 and 91 percent were post-processed using hot isostatic pressing (HIP) in argon gas. This treatment was shown to increase the TD up to 96%. Uranium nitride is highly reactive with oxygen. Therefore, a novel crucible design was implemented to remove impurities in the argon gas via in situ gettering to avoid oxidation of the UN kernels. Established characterization techniques for determining average weight, volume, and ellipticity of particle fuel was used for calculating the density before and after HIPing. Micrographs confirm the nearly full densification of the particles using the gettering approach and processing parameters investigated in this work.