“…Among many candidate ceramics, such as Al 2 O 3 , SiC, Si 3 N 4 , and AlN, magnesium aluminate spinel (MgAl 2 O 4 , Mg-Al spinel) shows excellent characteristics, even after highfluence neutron irradiation. Many studies on the neutronirradiation effects of spinel have been performed by Clinard, Hurley, and Hobbs et al, 7,[9][10][11][12][13][14][15][16] Kinoshita and co-workers, [17][18][19][20][21] Tucker et al, 22 Garner and co-workers, 23,24 Sickafus and coworkers, 25,26 Ibara et al, 27 and Yano and co-workers, [28][29][30][31][32][33][34] and exceptionally high performance of this ceramic has been established after irradiation up to high neutron fluences. The mechanism of insensitivity of Mg-Al spinel to neutron irradiation has been attributed to the difficulty in clustering point defects or dislocation loops and, consequently, void formation (based on crystal chemical considerations), 9,12,17,19,21 the presence of structural vacancies, 17,18 and the marked propensity of cation disorder.…”