Vitrification of Fission Product Solutions: Investigation of the Effects of Noble Metals on the Fabrication and Properties of R7T7 Glass

The effects of incorporating additional qualities of insoluble dissolution fines containing noble metals together with the fission product feed solutions were investigated for application to the French T7 vitrification facility at La Hague. Three types of tests were conducted: nonradioactive laboratory tests, radioactive laboratory tests, and industrial-scale tests in a prototype vitrification unit. The laboratory test results showed that the quality of R7T7 glass containing from 1.5 to 4 wt% of platinoids is fully equivalent to that of standard R7T7 glass without platinoids. These findings were confirmed on glass casting samples containing 0 to 3 wt% of platinoids from a full-scale industrial vitrification prototype facility. Recent tests in which video cameras have been used to visualize the molten glass and model simulations of glass properties and of melting pot behavior suggest that industrial operating conditions can be optimized to produce glass with platinoid concentrations approaching this limit value.