3 questions for Jean-Christophe Piroux

Director of Technologies and Innovation at Veolia Nuclear Solutions in Continental Europe

What is GeoMelt®?

It is a set of technologies based on a common platform to process a large amount of hazardous waste. GeoMelt® has treated nuclear and hazardous waste since the 1990s and has produced over 26,000 metric tons of glass for storage in the United States, the United Kingdom, Australia, Japan, and other countries.

How does GeoMelt® vitrify waste?

We use an oven, an enclosure composed of metal walls with a refractory coating, which is filled with a mixture of waste and glass frit*. Electrodes, inserted in the oven, allow the fusion process to begin by raising the temperature to around 1,200 degrees. Once the package is vitrified, it can be sent to the disposal facility.

We need to know the physicochemical composition of each type of waste as well as its activity. Based on this, we can order them to adjust the composition and make packages that meet the disposal facility criteria. The French National Radioactive Waste Management Agency (Andra) operates the disposal facilities and defines acceptance conditions based on the safety demonstrations validated by the French Nuclear Safety Authority (ASN).

What are the advantages of GeoMelt®?

This technology allows us to vitrify large volumes of waste with a wide variety of physicochemical properties. As waste is directly vitrified in the final storage container, there is no transfer or casting, which increases the safety of the operation.

In addition, GeoMelt® can halve — on average and up to 100% in some cases! — the initial volume of the treated waste, whereas it is generally increased five- to tenfold in a cement matrix.

The reduction in the volume of waste to be stored, the exceptional performance of the glass produced, the very flexible process, the ability to process waste of very varied composition and shape, and a solution for waste with no existing treatment channel are all plus points that make GeoMelt® a real alternative to existing processes.

Frit is a vitreous mixture obtained by fusing and grinding various components (primarily sand and soda).