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1181-DD13-06

Study of Silicon Carbide Ceramics Malek Abunaemeh , Ibidapo Ojo1, Mohamed Seif2, Claudiu Muntele1 and Daryush ILA1 1 Center for Irradiation of Materials, Alabama A&M University, Normal, AL 35762 2 Mechanical Engineering Department, Alabama A&M University, Normal, AL 35762 1

Abstract The TRISO fuel that is intended to be used for the generation IV nuclear reactor design consists of a fuel kernel of Uranium Oxide (UOx) coated in several layers of materials with different functions. One consideration for some of these layers is Silicon Carbide (SiC) [1]. The design, manufacture and fabrication of SiC are done at the Center for Irradiation of Materials (CIM). This light weight material can maintain dimensional and chemical stability in adverse environments and very high temperatures. The characterization of the elemental makeup of the SiC material used is done using X-ray photoelectron spectroscopy (XPS). Nano-indentation is used to determine the hardness, stiffness and Young's Modulus of the material. Raman Spectroscopy is used to characterize the chemical bonding for different sample preparation temperatures. Introduction Tristructural-isotropic (TRISO) fuel particles were originally developed in Germany for high-temperature gas-cooled reactors[1].The first nuclear reactor to use TRISO fuels was the AVR, a prototype pebble bed reactor at Jülich Research Centre in West Germany, and the first power plant was the THTR-300, a thorium high-temperature nuclear reactor rated at 300 MW electric. TRISO fuels are also being used in experimental reactors such as the HTR-10 in China and the HTTR in Japan. TRISO is a type of micro fuel particle. It consists of a fuel kernel composed of Uranium dioxide (UOX) [1,2] in the center, coated with four layers of three isotropic materials. The four layers are a porous buffer layer made of carbon, followed by a dense inner layer of pyrolytic carbon (PyC), followed by a ceramic layer of SiC to retain fusion products at elevated temperatures and to give the TRISO particle more structural integrity, followed by a dense outer layer of PyC. TRISO fuel particles are designed not to crack due to the stresses from different processes (such as differential thermal expansion or fusion gas pressure) at temperatures beyond 1600°C. Therefore it can contain the fuel in the worst accident scenarios in a properly designed reactor. Two such reactor designs are the pebble bed reactor (PBR), in which thousands of TRISO fuel particles are dispersed into graphite pebbles, and the prismatic-block gas-cooled reactor (such as the GT-MHR), in which the TRISO fuel particles are fabricated into compacts particles[2] and placed in a graphite block matrix. Both of these reactor designs are very high temperature reactors (VHTR) [formally known as the high-temperature gas-cooled reactors (HTGR) [2], one of the six classes of reactor designs in the Generation IV initiative. The TRISO fuel is directly immersed in the cooling fluid that extracts the heat outside of the reactor core while keeping the inside wi