Effects of phosphorous-doping and high temperature annealing on CVD grown 3C-SiC

作     者：van Rooyen, I. J. Neethling, J. H. Henry, A. Janzen, E. Mokoduwe, S. M. van Vuuren, A. Janse Olivier, E. 

作者机构：CSIR Natl Laser Ctr ZA-0001 Pretoria South Africa Nelson Mandela Metropolitan Univ Dept Phys ZA-6031 Port Elizabeth South Africa PBMR ZA-0046 Centurion South Africa Linkoping Univ Dept Phys Chem & Biol S-58183 Linkoping Sweden 

出 版 物：《NUCLEAR ENGINEERING AND DESIGN》 (核工程与设计)

年 卷 期：2012年第251卷

页      面：191-202页

核心收录：

学科分类：08[工学] 0827[工学-核科学与技术] 

基　　金：PBMR's Fuel Optimization Technology Programme 

主　　题：advance coater facility ( ACF ) atomic force microscopy ( AFM ) bright field ( BF ) chemical vapor deposition ( CVD ) coated particle ( CP ) electron back scatter diffraction ( EBSD ) Evans Analytical Group ( EAG ) Fourier transformed infrared ( FTIR ) high resolution transmission electron microscopy ( HRTEM ) high temperature reactors ( HTR ) Linköping University ( LiU ) Nelson Mandela Metropolitan University ( NMMU ) Oakridge National Laboratory ( ORNL ) scanning electron microscopy ( SEM ) secondary ion mass spectrometry ( SIMS ) selected area diffraction ( SAD ) tertiary butyl phosphine ( TBP ) transmission electron microscopy ( TEM ) tri-isotropic ( TRISO ) X-ray diffraction ( XRD ) 

摘      要：The integrity and property behavior of the SiC layer of the Tr-isotropic (TRISO) coated particle (CP) for high temperature reactors (HTR) are very important as the SiC layer is the main barrier for gaseous and metallic fission product release. This study describes the work done on un-irradiated SiC samples prepared with varying phosphorus levels to simulate the presence of phosphorus due to transmutation. Si-30 transmutes to phosphorous (P-31) and other transmutation products during irradiation, which may affect the integrity of the SiC layer. The P-doping levels of the SiC samples used in this study cover the range from 1.1 x 10(15) to 1.2 x 10(19) atom/cm(3) and are therefore relevant to the PBMR operating conditions. Annealing from 1000 degrees C to 2100 degrees C was performed to study the possible changes in nanostructures and various properties due to temperature. Characterization results by X-ray diffraction (XRD), secondary ion mass spectrometry (SIMS), scanning electron microscopy (SEM). transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM), are reported in this article. As grain boundary diffusion is identified as a possible mechanism by which Ag-110m, one of the fission activation products, might be released through intact SiC layer, grain size measurements is also included in this study. Temperature is evidently one of the factors/parameters amongst others known to influence the grain size of SiC and therefore it is important to investigate the effect of high temperature annealing on the SiC grain size. The ASTM E112 method as well as electron back scatter diffraction (EBSD) was used to determine the grain size of various commercial SiC samples and the SiC layer in experimental PBMR Coated Particles (CPs) after annealing at temperatures ranging from 1600 degrees C to 2100 degrees C. The HRTEM micrograph of the decomposition of SiC at 2100 degrees C are shown and discussed. Nanotubes were not identified during