초록 ▼

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 surfact

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 turbular 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.

대표청구항 ▼

The method of making an annular neutron-absorber body for use as a burnable poison in a nuclear reactor, said body being porous and having substantially uniform density, the radial thickness of said body being small and substantially uniform, throughout its length, the said method comprising: (a) mi

The method of making an annular neutron-absorber body for use as a burnable poison in a nuclear reactor, said body being porous and having substantially uniform density, the radial thickness of said body being small and substantially uniform, throughout its length, the said method comprising: (a) mixing a first powder with a second powder, said first powder to form a matrix, and being selected from one or more of the class consisting of aluminum oxide (Al2O3) and zirconium oxide (ZrO2), said second powder being a neutron absorber and being selected from one or more of the class of elements consisting of boron, gadolinium, samarium, cadmium, europium, hafnium, dysprosium and indium or their compounds; (b) milling and grinding the mixture of said first powder and said second powder in a liquid to produce a slurry in which said powders are homogenized and coarse agglomerates are eliminated, said slurry including water, and small but effective quantities of a wetting agent; (c) drying said slurry to produce a dry mass of said mixture of said first and second powders; (d) adding to said mass of powders means capable of adding strength to a green body to be formed of said mass of powders; (e) depositing said mass of powders into a mold in which said mass may be subjected to isostatic pressure; (f) subjecting said mass of powders in said mold to isostatic pressure to form a green body having the form of an annular neutron-absorber body; and (g) heating said green body at a temperature such as to drive off said strength-adding means and to sinter said green body to form said neutron-absorber body.