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

Abstract This paper reports on the microstructure and properties of two glass–ceramics based on SiO 2 –Al 2 O 3 –MgO (SAMg) and SiO 2 –Al 2 O 3 –Y 2 O 3 (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 °C, 6.92 × 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 °C, 9–11 × 10 24  n/m 2 ( E  > 1 MeV, about 1.4–1.8 dpa in C), 600 °C, 16–22 × 10 24  n/m 2 ( E  > 1 MeV, about 2.6–3.3 dpa in C) and 820 °C 31–32 × 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.