RESEARCH INTO THE EFFECT OF PARTICLE SIZE DISTRIBUTION OF NEUTRON-ABSORBING POWDER MATERIALS ON THE COMPACTION IN ABSORBING ROD CLADDINGS

The results of research into the effect of the granulometric compositions of neutron-absorbing powder materials such as boron carbide, dysprosium titanate and dysprosium hafnate and their mixtures in the initial state on the characteristics of backfills in the claddings of both “short” and full-size absorbing rods are presented. It was revealed that the achievement of the maximum backfill density is facilitated by providing the content of a fine fraction of about 30%. The maximum backfill density values achieved for boron carbide, dysprosium titanate, and dysprosium hafnate were 1.82, 5.1, and 5.82 g/cm3 respectively. The optimal modes of vibration compaction (type and frequency of oscillations), which ensure the achievement of the required values of the backfill density in absorbing rods in a short time were defined.