[THESIS DEFENSE] MISSP/CIMEND - AUFFRET Ewen
Soutenance de thèse
Amphi Loison C7
Dear All,
It is my pleasure to invite you to the defense of my PhD thesis entitled: «Development and optimization of a process for attacking the oxidation layer of nuclear assembly cladding materials for decontamination purposes»
It will take place the Thursday 13th of november 2025 at 14 h in the amphitheatre Loison, Batiment C7, rue Medeleiev, 59650 Villeneuve-d'Ascq.
To assist to the defense you have to fill the confidentiality release attached to this mail.
The defense will be follow by a small buffet at chevreul institue to celebrate this moment together.
Jury composition:
| M. Mathieu ALLIX | Thesis reporter | Research director, CEHMTI, Université d’Orléans |
| M. Pierre CHAMELOT | Thesis reporter | Pr, Université de Toulouse III Paul Sabatier |
| Mme Anne-Laure ROLLET | Thesis examiner | Resarch officer, PHENIX, Université de la Sorbonne |
| M. Jérôme SERP | Thesis examiner | Engeneer, CEA de Marcoule |
| M. Anthony ROPP | Thesis examiner | Engeneer, Orano |
| Mme Mathilde GUILPAIN | Thesis supervisor | Engeneer, Orano |
| Mme Marie COLMONT | Thesis co-director | Pr, Centrale Lille |
| Mme Sylvie DAVIERO | Thesis co-director | Pr, Université de Lille |
Key words:
| Oxid, molten salts, dissolution, hulls, decontamination |
Summary:
| The REGAIN project aims to reprocess fuel cladding, which is classified as MA-VL waste and therefore destined for storage at the CIGEO site. As the cost of storage is linked to the volume and level of activity of the waste, it is now essential to work on reducing the volume of higher-activity waste to be stored in CIGEO, given the limited space available for this type of storage and its very high cost. The aim of this thesis is to dissolve the layer of zirconium oxide which forms on the surface of the cladding during irradiation, and which contains the majority of the radioactive part. For the dissolution of the oxide, molten salts were chosen as the reaction medium. Indeed, molten salts offer a number of advantages for completing this task: high dissolving power, stable at high temperatures, stable to radiolysis, recyclable and can act as a sequestration matrix once resolidified for the contaminants. K2S2O7 was chosen for the attack and the reactions between this salt and the oxide layer’s elements were studied. After the oxide dissolution, the dissolved elements could be separated from the salt by a method using a calcination of the bath followed by a liquid/solid separation and the salt can finally be regenerated by rebalancing the SO4^2- proportions and evaporation of the solvent. | ||
Looking forward to seeing you there.
Best regards,
Ewen Auffret