Ruthenium, palladium and rhodium, which belong to noble metals group (NM), are fission products in high-level waste (HLW) resulting from reprocessing of nuclear spent fuel. All HLW vitrification facilities have experienced operational problems that can be related to the presence of NM in the melter. These metals, and their alloys and compounds, have very low solubility in glass and modify the glass properties such as viscosity or electrical conductivity. These dense metals also tend to settle to the bottom of the melter. Whatever the melting process, the specific properties and behavior of NM could decrease the process throughput and increase the melter downtime. To avoid these problems CEA and AREVA have studied behavior of NM in borosilicate glass over the years. Several technological improvements such as multiple bubbling and mechanical stirring have been implemented on the Hot Crucible Melter (HCM) following R&D studies in order to increase throughput and NM content in glass. The behavior of NM was taken into account in the design of the new Cold Crucible Induction Melter (CCIM). As a consequence, the CCIM should be able to increase glass throughput with the same NM content as the HCM. INTRODUCTION All high-level waste vitrification facilities have experienced operational problems arising from the presence of noble metals in the melter, related to their specific properties and behavior in the glass. Ruthenium, palladium and rhodium, which belong to noble metals group(NM), are fission products in high-level waste (HLW) resulting from reprocessing of nuclear spent fuel. Most of the high-level waste in France arises from reprocessing UOX fuel containing a significant proportion of NM in relation with their burnup. At the La Hague plant in France, noble metals in solution enter the vitrification units in two separate flow streams: fission products and fines. Shearing and fuel dissolution result in a nitric acid solution containing the uranium, plutonium, and fission products. This solution contains small, solid particles composed of Zr, Mo and noble metals (Ru, Pd, Rh). These small particles, known as “fines”, are then separated from the dissolution solution by centrifugation and constitute the fines solution. The fission products solution is obtained after separation of the uranium and plutonium.