Effects of neutron irradiation on glass ceramics as pressure-less joining materials for SiC based components for nuclear applications

This paper reports on the microstructure and properties of two glass-ceramics based on SiO2-Al2O3-MgO (SAMg) and SiO2-Al2O3-Y2O3 (SAY), which have been designed to be used as pressure-less low activation joining materials for SiC/SiC and SiC based components for nuclear applications. Glass-ceramic pellets (SAY and SAMg) were irradiated for approximately 1 year in the reactor core of the LVR-15 research reactor at Nuclear Research Institute Rez, Czech Republic, at about 50 degrees C, 6.92 x 10(24) n/m(2) (E > 1 MeV, about 1 dpa in steel); SiC/SiC composites joined by SAY were irradiated about 1 year at High Flux Reactor (HFR), Petten, The Netherlands, 550 degrees C, 9-11 x 10(24) n/m(2) (E > 1 MeV, about 1.4-1.8 dpa in C), 600 degrees C, 16-22 x 10(24) n/m(2) (E > 1 MeV, about 2.6-3.3 dpa in C) and 820 degrees C 31-32 x 10(24) n/m(2) (E > 1 MeV, about 5 dpa in C). Optical microscopy with image analysis and scanning electron microscopy (SEM) with X-ray microanalysis (EDS) were used to investigate the glass-ceramics morphology and composition, showing a remarkable similarity before and after neutron irradiation for both glass-ceramics. Comparison of bending strength for irradiated and non-irradiated SAY joined SiC/SiC indicate that the mechanical strength is unaffected by irradiation at these conditions. (C) 2012 Elsevier B.V. All rights reserved.