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The full-scale cold crucible test on vitrification of sludge batch 4 (SB4) Savannah River Site HLW surrogate using a 418 mm inner diameter stainless steel crucible was carried-out for 66 hrs. Commercially available Frit 503-R4 (8 wt.% Li 2 O, 16 wt.% B 2 O 3 , 76 wt.% SiO 2 ) was used as a glass forming additive at a calcine to frit ratio of 1:1 (50 wt.% calcine, 50 wt.% frit). Two portions of slurry prepared from frit and mixture of chemicals simulating waste in amount of ~750 kg and from frit and waste surrogate prepared by the SRT-MST-2007-00070 procedure in amount of ~1,300 kg with water content of ~27 and ~50 wt.%, respectively, was processed and ~875 kg of the vitrified product in total (~415 + 460 kg) was obtained. Average parameters were as follows: vibration power -121.6 to 134.1 kW, feed rate (capacity) -25.1 to 39.8 kg/hr, glass pour rate (productivity) -14.0 kg/hr specific energy expenses for feed processing -4.8 to 3.4 kW×hr/kg, specific energy expenses for glass production (melting ratio) -8.7 to 9.6 kW×hr/kg, specific glass productivity -2453 kg/(m 2 ×d). The product was composed of major vitreous and minor spinel structure phases. No nepheline phase was found. Average degree of crystallinity was estimated to be ~12 vol.%. Cesium was found to be the most volatile component (up to ~60 wt.% of total). Lithium, sodium and boron are less volatile. Other major feed constituents (Al, Si, Mg, Fe, Mn) were not volatile but their carry-over with gas-vapor flow occurred.

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Bench and commercial-facility experiments have been performed on cold-crucible vitrification of a simulator of high-level wastes from the Savannah River site (USA). The wastes contained up to 29 mass% Fe 2 O 3 and 26 mass% Al 2 O 3 . The specific product flow reached 1700 and 2450 kg/(m 2 ·day) with specific energy consumption 14-16 and 9-10 kW·h/kg, respectively. The crucibles did not undergo any appreciable corrosion during the period of the work performed and are reusable. The product consisted of a borosilicate matrix, containing up to 10 vol.% crystalline phase of spinel. The method of induction melting in a cold crucible is especially effective for crucibles with a large diameter, since the specific productivity increases and the specific energy consumption on the vitrification of high-level wastes decreases.The successful demonstration of the possibility of vitrifying iron-containing high-level wastes -SB2 pulps from tanks at the Savannah River site -by the method of induction melting in a cold crucible [1, 2] has made it possible to proceed to the next stage of the work -a study of the possibility of vitrifying a simulator with a high content of iron and aluminum -SB4 pulps ( Table 1). The same bench and commercial facilities for vitrifying liquid radioactive wastes from the Moscow Scientific and Industrial Association Radon with 520 and 860 mm high cold crucibles with inner diameters 216 and 418 mm, respectively, were used for this purpose.A high concentration of sodium and aluminum in the wastes created a danger of chemically unstable phases of nepheline forming, so that the American specialists developed the frit composition 503-R4, which does not contain sodium oxide [3] and makes it possible to obtain glass, satisfying the criterion SiO 2 /(SiO 2 + Na 2 O + Al 2 O 3 ) > 0.62 (the concentration of the components is expressed in mass fractions), without crystallization of nepheline [4].For the experiment on the bench facility, the wastes simulator was prepared from the reagents with the addition of water. The reagents H 3 BO 3 , Li 2 CO 3 , and SiO 2 were taken in the mass ratio corresponding to be 503-R4 frit: 16 B 2 O 3 , 8 Li 2 O, and 76 SiO 2 . Two portions of a batch were prepared in the form of sludge containing 40 and 60 mass% of wastes oxides in the glass and 31-32 and 42-43 mass% water (B1 and B2), respectively.