Continuous vitrification of concentrated fission product solutions

Converting fission product solutions into a solid, vitrified product for safe ultimate storage is the approach pursued by France in the treatment of this type of waste. The continuous vitrification technique developed by the CEA for the conversion of fission product solutions at the same time helps to greatly reduce the volume of such solutions. The equipment used for this purpose, i.e., a rotary calciner for calcination of the solution and a melting furnace for vitrification of the calcination product, is described in the article. The results of experiments conducted on the equipment in a prototype system built at the Marcoule Nuclear Research Center for a total of approximately 7,400 hours are reported and discussed. Also a new vitrification furnace is described which operates by direct induction in the molten glass. Thanks to the satisfactory results achieved with respect to performance and reliability of the equipment, the development of this line has been extended up to the industrial scale. A system employing this principle has been set up on the Marcoule site. (orig./HPH)