News Academy of Engineering Sciences A.M. Prokhorov Annotation << Back The effect of irradiation on the structure and properties of carbonitride fuel A.B. Gaiduchenko G.E. Kiknadze E.M. Remiz Samples of U-Zr-C-N nuclear fuel were investigated. Duration of irradiation of fuel rod from which samples were cut was 8300 hours; more than 30 years have passed after irradiation. The microstructure of the fuel samples was investigated by scanning electron microscopy. Three annular zones along tablet radius are clearly distinguished in all samples: middle zone, the inner and outer zones, characterized by the different types of porosity: technological pores (size 1–5 μm) and radiation pores (10–20 nm) of regular shape are presented. The gap between cladding and fuel was investigated. The gap between fuel and cladding is not overgrown during irradiation. Its width at different places is between 50 and 100 μm. Layer of re-condensed fuel of thickness 40–60 μm in the form of columnar crystals is presented on inner surface of cladding. The distribution of uranium in the recondensed fuel-cladding interface was studied by X-ray analysis. Keywords: nuclear thermal propulsion reactor, carbonitride nuclear fuel, X-ray analysis, scanning electron microscopy. Contacts: E-mail: gaiduchenko@irtm.kiae.ru Pp. 31-37.