Characterization of Changes in Properties and Microstructure of Glassy Polymeric Carbon Following Au Ion Irradiation
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1215-V16-26
Characterization of Changes in Properties and Microstructure of Glassy Polymeric Carbon Following Au Ion Irradiation Malek Abunaemeh1,2*, Mohamed Seif3, Young Yang4, Lumin Wang5, Yanbin Chen5, Ibidapo Ojo1,2, Claudiu Muntele1 and Daryush Ila1,2 1
Center for Irradiation of Materials, Alabama A&M University Research Institute, Normal, AL 35762 2 Physics Department, Alabama A&M University, Normal, AL 35762 3 Mechanical Engineering Department, Alabama A&M University, Normal, AL 35762 4 Engineering Physics Department, University of Wisconsin, Madison, WI, 53706 5 Department of Nuclear Engineering & Radiological Sciences, University of Michigan, Ann Arbor, MI 48109-2104 * Corresponding author
Abstract The TRISO fuel has been used in some of the Generation IV nuclear reactor designs [1,2]. It consists of a fuel kernel of UOx coated with several layers of materials with different functions. Pyrolytic carbon (PyC) is one of the materials in the layers. In this study we investigate the possibility of using Glassy Polymeric Carbon (GPC) as an alternative to PyC. In this work, we are comparing the changes in physical and microstructure properties of GPC after exposure to irradiation fluence of 5 MeV Au equivalent to a 1 displacement per atom (dpa) at samples prepared at 1000, 1500 and 2000°C. The GPC material is manufactured and tested at the Center for Irradiation Materials (CIM) at Alabama A&M University. Transmission electron microscopy (TEM), Rutherford backscattering spectroscopy (RBS), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy were used for the analysis. INTRODUCTION Current high temperature gas cooled rectors are designed with the use of coated fuel particles that are dispersed in a graphite matrix to form fuel elements called Tristructural-isotropic (TRISO) [1,2]. As seen in figure 1[3], TRISO consists of a microspherical kernel of uranium oxide (UOx) coated with a layer of porous carbon buffer surrounding it to contain any particle dimensions changes or gas buildup. This layer is followed with an inner pyrolitic carbon (PyC) followed by a layer of silicon carbide (SiC) followed by an outer PyC layer.
Figure 1: TRISO fuel layers structure
The pebbles or the graphite blocks containing the TRISO fuel is directly immersed in the cooling fluid that extracts the heat outside of the reactor core while keeping the inside within the operational temperature limits [4,5]. If the fissile fuel is in direct contact with the cooling fluid, there are great chances that radioactive fission fragments will be carried out of the reactor core and contaminate all other equipment [6]. Therefore, in order to minimize such leaks, TRISO is designed with PyC as the diffusion barrier material. GPC is widely used for various applications from artificial heart valves to heatexchangers and other high-tech products that are developed for the space and medical industries. This lightweight material can maintain dimensional and chemical stability in adverse environment and very high temperatures (up to 3000°C). The
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