Date of Award

1-1-2009

Document Type

Campus Access Thesis

Department

Nuclear Engineering

First Advisor

Travis W. Knight

Abstract

Recent studies of TRISO fuel behavior have shown a number of problems with the conventional SiC TRISO coating system at very high temperature, not unlike the temperatures obtainable in the very high temperature reactor (VHTR) design. These problems include but are not limited to over pressurization of the kernel due to fission gas buildup as well as kernel migration, in the presence of a temperature gradient, known as the amoeba effect. To negate these problems a solution of adding a ZrC gettering layer between the kernel and PyC buffer layer has been proposed. The purpose of this study is to provide insight into the coating parameters and how they affect the coating properties. Advanced TRISO coatings consisting of a ZrC getter are applied to surrogate kernels which represent the oxide fuel kernel of a VHTR. The coatings are then analyzed via optical and electron microscopy techniques to visually verify coating integrity. Further analysis is done using XRD to confirm that ZrC has been deposited. Density measurements are performed using a helium pycnometer to ensure coating densities meet or exceed 95% theoretical density.

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