Spinel crystal distribution and settling in a high-level waste melter working as a perfect mixer - Part 1. Theoretical relations

The mathematical and laboratory modeling of the high-level waste vitrification process is able to reveal. the mechanism of spinel crystal formation, their interaction with a melt and settling. This enables to find conditions for higher waste loading into vitrification facility. A model of a perfect mixer has been developed by authors with the aim to examine the crystal settling and to compare results with the numerical mathematical model. This model is based on the mass balance of inputted, outputted, nucleated, growing or dissolving and settling crystals in the melting space. To complete the description of possible melter behavior similar relations were derived and are presented for the piston flow in the melter.