In the frame of the dismantling and decommissioning of nuclear power plants, various waste streams are produced that must be treated and conditioned for long-term disposal. One of these waste streams are spent ion exchange resins. The focus of the conditioning lies on the one hand on ensuring safe final matrix properties, on the other hand on waste volume minimization. The most common conditioning technique is the mixing of the radioactive waste with cement with the aim to form a stable matrix for the final storage.

Framatome developed a liquefaction process for the treatment of spent ion exchange resins. These liquefied ion exchange resins are then solidified for long-term storage via cementation. The liquefaction as a pretreatment step allows both homogenization of the resulting waste for improved cement matrix properties as well as waste volume reduction by concentration of the resulting product.

The optimization of the cementation recipe for the solidification of the liquefied spent ion exchange resins aims at maximizing the waste proportion in the cement matrix while still ensuring required properties, like compressive strength, leaching resistance, resistance to water as well as temperature etc.

For this task, the following is envisioned:

• Literature review on cement composition and properties.
• Elaboration and testing on laboratory scale of mechanical properties of different cement matrices (using non-radioactive liquefied spent resins).
• Analysis, discussion of results and elaboration of report.