Thermodynamically stable product for permanent storage and disposal of

Abstract

Highly radioactive liquid wastes are permanently stored in a solidification matrix containing the components of a known borosilicate glass together with nucleation agents selected from the group consisting of oxides of Li, K, Mg, Mo and Cr, fluorides of those metals and of Al, and pure noble metals in the elemental form with particles with sizes smaller than 0.1 .mu.m in diameter, and up to 35% by weight of waste fission and corrosion products or waste fission and corrosion products and gadolinium oxide. The product is produced by denitrating and calcining the radioactive waste solution, melting the calcined waste product together with a borosilicate frit containing nucleation agents at a temperature of between 1,050.degree. and 1,200.degree. C, and maintaining it in its melted state for 3 to 5 hours, subsequently cooling the resulting mixture until to a given temperature and maintaining it at this temperature for a given time period to permit nucleation to occur, then elevating the temperature of the mixture with an constant heating rate until to a given higher temperature, maintaining it at this higher temperature for about 24 hours, and finally cooling it with a constant cooling rate to ambient temperature.