A novel coated-particle design and fluidized-bed chemical vapor deposition preparation method for fuel-element identification in a nuclear reactor

摘要

Particle coating is an important method that can be used to expand particle-technology applications.Coated-particle design and preparation for nuclear fuel-element trajectory tracing were focused on in this paper.Particles that contain elemental cobalt were selected because of the characteristic gamma ray spectra of 60Co.A novel particle-structure design was proposed by coating particles that contain elemental cobalt with a high-density silicon-carbide (SiC) layer.During the coating process with the highdensity SiC layer,cobalt metal was formed and diffused towards the coating,so an inner SiC-CoxSi layer was designed and obtained by fluidized-bed chemical vapor deposition coupled with in-situ chemical reaction.The coating layers were studied by X-ray diffractometry,scanning electron microscopy,and energy dispersive X-ray spectroscopy techniques.The chemical composition was also determined by inductively coupled plasma optical emission spectrometry.The novel particle design can reduce the formation of metallic cobalt and prevent cobalt diffusion in the coating process,which can maintain safety in a nuclear reactor for an extended period.The experimental results also validated that coated particles maintain their structural integrity at extremely high temperatures (～1950 ℃),which meets the requirements of next-generation nuclear reactors.