Linear thermal expansion of thoria, urania-thoria, and their dispersions in beryllia in the range 20-1000°C, together with improved data for beryllia

Abstract

Differences in the thermal expansion properties of the dispersed phase and matrix of a beryllia based fuel can give rise to stresses in the material on cooling. In beryllia the strains can be very large. By means of a dilatometric method the linear thermal expansion properties of thoria, urania -thoria L(U,Th)O2 with U:Th = 1:10 J and dispersions of 20 vol. per cent of each in beryllia for the range 20—1000ºC have been measured. The results are given, together with some improved data for beryllia. The data obtained for thoria are compared with published data and the thermal expansion of composite bodies is discussed. There is evidence that the particles of the dispersed phase are bonded to the matrix.