Investigation of Zirconium Carbide Ceramic Coating on Surrogate Kernels Deposited by Plasma-Pulsed Laser Deposition: A Preliminary Study

Abstract

High Temperature Gas-cooled Reactor (HTGR) is one of advanced nuclear reactors with high safety system feature. Indonesia has a plan to build HTGR as an Experimental Power Reactor (in Indonesian: RDE - Reaktor Daya Eksperimental). One of the safety system feature is its fuel system. There are two types of fuel of HTGR i.e. pebble bed type and prismatic type which all of the types are containing TRISO (Tri-Structural Isotropic) which consist of Inner Pyrolitic Carbon, SiC (Silicon Carbide) dan Outer Pyrolitic Carbon. One of the issues of the system is silver (Ag) and palladium (Pd) as the fission product could interact with SiC layer and cause corrosion. One of the candidate to resolve the issue is to replace SiC with ZrC (Zirconium Carbide). In this preliminary study, Zirconium Carbide ceramic has been deposited on a surrogate (uranium-free) fuel microkernels using PLD Plasma-Pulsed Laser Deposition. The parameter during ZrC deposition were temperature of 850°C for the substrate, the number of laser shots of 90,000 and the oxygen background gas with 40 sccm (standard cubic centimeters per minute) with the chamber pressure of 235 mTorr. Thereafter, the samples were analyzed using OM - Microscope Optic, SEM-EDS - Scanning Electron Microscope – Energy Dispersive X-ray Spectroscope, XRD – X-Ray Diffractometer and AFM – Atomic Force Microscope. The results exhibited that the ceramic coating could deposited on the surface of the substrate surface with homogeneously and sticky. The surface was very smooth within the nano-meter range order of ∼80-120 nm of surface roughness. Nevertheless, the results indicated that some of ZrC was react with oxygen at high temperature on the surface of the sample and deposited on the surface of surrogate microkernels.