BRAENNBAR ABSORBATORKROPP FOER ANVAENDNING I EN KAERNBRAENSLEPATRON

摘要

An improved annular burnable poison pellet of aluminum oxide-boron carbide (Al2O3-B4C) adapted for positioning in the annular space of concentrically disposed zircaloy tubes. Each tubular pellet is fabricated from Al2O3 powders of moderate sintering activity which serves as a matrix for B4C medium size particle distrbution. Special pellet moisture controls are incorporated in the pellet for moisture stability and the pellet is sintered in the temperature range of 1630 DEG -1650 DEG C. This method of fabrication produces a pellet about 2 inch long with a wall thickness of about 0.020 inch to 0.040 inch. Fabricating each pellet to about 70% theoretical density gives an optimum compromise between fabricability, microstructure, strength and moisture absorption.