Uranium and thorium in LSI materials were determined by INAA and α-particles in these materials were also measured. The contents
of uranium and thorium and the α-activity in ceramics and zirconia samples were very high. Calculation of α-flux from uranium
and thorium contents and analysis of α-spectra were carried out for the ceramics and zirconia samples. The calculated values
of α-flux in these samples agreed with the α-flux measured.