Method of making annular pellets for use as burnable neutron absorbers.

摘要

Annular pellets of burnable poison specifically boron carbide, B4C, in a matrix of a refractory material, specifically aluminum oxide, Al2O3, are produced, The pellets are of small wall thickness. Powders of the Al2O3 and the B4C are milled in a ball mill in water in which a wetting agent, a surfactant and a deflocculant are included to produce a slurry. Organic binders and plasticizers are added. Then the slurry is spray dried in a centrifugal separator. The resulting powder is poured into a mold and a tubular green body is formed by isostatic pressure. The tube may be sintered to size as a whole and then cut into lengths; i,e., pellets, or the green body may be cut into green-body pellets which are then sintered.