Waste vitrification melter

Abstract

A glass melter for vitrifying material including radioactive and hazardous materials. In one embodiment, the melter comprises an inner vessel or container having a solidified glass skull, at least one pair of vertically-oriented, retractable electrodes, a first wall spaced apart from said inner vessel to define a dry annulus therebetween for radiatively cooling the inner vessel, and a second wall spaced apart from said first wall to define a second annulus that serves as a water jacket when filled with water. Each electrode has a protective sleeve therearound with means formed therebetween for passing a purging gas therethrough. A central access nozzle allows waste material and glass formers to be fed into the inner vessel while simultaneously venting the off-gas generated in the inner vessel. Also, the dry annulus can have fluid circulating therethrough for regulated cooling or leak detection. An alternative embodiment contains a top entry glass tap, allowing the removal of vitrifiable material without penetrating the skull of the melter. Another embodiment provides a retractable oxygen lance which provides oxygen control to both the atmosphere above the batch and the batch itself, and a dual melt zone drain assembly which can provide enough energy from cold startup to activate the electrodes. The drain assembly also has a separately heated nozzle which, when deenergized, prevents material from exiting the melter. The melter includes, in the preferred embodiment, a bottom electrode that can provide direct heat input at the drain orifice.