[en] The bases for control of electric melters with high level radioactive waste feed are complex. Preliminary limits are described for vitreous immobilization of high level radioactive waste at the US Department of Energy's Savannah River Site (SRS) in the Defense Waste Processing Facility (DWPF). Limits will be finalized based on extensive operation of the actual DWPF equipment, using simulated radioactive feed. Radioactive waste-glass production requires chemical control to assure adequate durability (aqueous leach resistance), physical control limits and glass composition control to assure continuous melter operation, and to sustain glass production. Glass composition, melter feed batching and melter temperature control are used to produce waste glass with adequate durability in a manner which avoids the formation of phases which are disruptive to melting or reduce melter life. Alternative control methods of product and process controls have been considered. It has been determined that product control and glass melting temperature controls the quality of the glass product. Further, it has been determined that process control is necessary to maintain the efficient operation of the facility. The essential requirements are maintenance of melter operation, control of the chemical composition of the mixtures fed to waste glass melters, and a minimum time at temperature to fuse the feed into a glass product. Variables considered for control in waste glass production include: temperature, glass residence time in melter, glass composition, glass durability limits, glass solubility limits, waste loading limits, glass redox control, combustible gas accumulation and sooting, glass cooling rate control, glass devitrification control, and glass cracking control. 56 refs., 1 tab