Joule ceramic melter research annual report for 1986/87

Engineering work on the full-scale Joule Ceramic Melter has been suspended owing to a reduction in funding. Work on the Experimental Test Melter has included the measurement of temperature distributions and electrical resistivity on a charge of precursor 241 glass. A new metallic viscometer for measuring viscosity in situ has been tested. Some simplified mathematical models of various conducting sediments have been examined. Batches of the reference glass 241 for present PFR waste have been made by pot vitrification and the rotary calciner/metallic melter routes. Foaming occurred during pot vitrification. Crystalline phases and sediments of RuO2 with reduced electrical resistivity were formed. The presence of Na NO3 in PFR waste leads to problems during calcination which can be alleviated by adding Al. (author)