Compatibility of two Idaho Chemical Processing Plant glasses with electric melting processes

High-level liquid nuclear wastes produced at the Idaho Chemical Processing Plant (ICPP) was converted to a dry calcine powder. The feasibility of converting this calcine to a durable waste glass is being evaluated at ICPP. Candidate waste glass compositions were developed and plans were made to construct and operate a laboratory electric glass melter at INEL. The Pacific Northwest Laboratory (PNL) examined the electric melter processing characteristics of two Idaho developed waste glasses, ICPP Zr-13 and ICPP Zr-51. This preliminary evaluation found both borosilicate glasses acceptable candidates for electric melting trials. The high temperature resistivity, viscosity, and corrosion behaviors are consistent with PNL melting experience. The ICPP calcine characteristics, waste glass volatility, and waste glass devitrification behavior have not been previously encountered at PNL. Several melter operation and design options are available to deal with all of these conditions. Additional work in three basic areas is, however, suggested for the final candidate waste glass composition: volatility - species identification; corrosion behavior of electrodes at operating temperatures; and means of improving melting rates and glass homogeneity. Reducing the devitrification tendency of the candidate waste glass will significantly improve the stability and control of an electric glass melting process.