Communication Dans Un Congrès Année : 2019

Microwave sintering of nuclear ceramics

Résumé

Mixed oxides (MOX) made of PuO2 and UO2, in the form of sintered pellets, are used as fuel in nuclear reactors. The sintering step is generally carried out at high temperature (about 1700°C) in an electrical resistance furnace. Therefore, there is a need to optimize manufacturing processes and especially to reduce economic and energetic costs. To this aim, microwave heating has been extensively investigated as an alternative technology for sintering of ceramics. In this process, the ceramic components are directly heated by absorption of the microwaves, leading to substantial savings in processing time and energy. It is known that actinide oxides have high dielectric losses, thus can be heated at high temperatures with microwaves. However, very few studies reported the fabrication of sintered UO2 pellets employing microwave heating. The main issues of these studies are the poor reproducibility and the lack of relevant comparison between conventional and microwave sintering. Therefore, the main aim of this work is to perform an in-depth study of the microwave sintering of nuclear ceramics. The control of the heating cycle and the measurement of sample’s shrinkage are of particular importance to highlight possible microwave effects during sintering. For this purpose, a suitable cavity for multimode microwave sintering was designed and fabricated. The cavity was developed to be used in a glovebox (dimensions, handling of the setup) while allowing an optimized heating of the samples. A sintering cell was also designed with the aim of uniformly heating the sample. The cavity and the sintering cell were fabricated and improved thanks to finite element simulations and preliminary tests with a surrogate of UO2. The microwave sintering setup also includes different devices for non-contact measurement methods such as pyrometers for temperature and optical dilatometer for shrinkage measurement of the sample. First sintering tests of UO2 pellets showed the feasibility of microwave sintering with a shorter thermal cycle (lower than 4 hours) and a shorter energy consumption compared to conventional sintering. In situ and non-contact measurements of temperature and shrinkage now allow a relevant comparison of conventional and microwave sintering of MOX samples. It will then be possible to investigate the existence of a possible microwave effect during sintering of MOX and actinide oxides.

Domaines

HAL

Est identique à hal-02441911 Objet présenté à une conférence F. Valdivieso, S. Saunier, J. Croquesel, S. Pillon-Eymard. Microwave sintering of nuclear ceramics. NuMat 2016, Nov 2016, Montpellier, France. ⟨hal-02441911⟩

Les dépôts hal-02441911v1 et hal-04907597 ont le même titre mais correspondent bien à deux contributions différentes : deux participations à deux congrès différents avec un même titre.
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Dates et versions

hal-04907597 , version 1 (23-01-2025)

Identifiants

  • HAL Id : hal-04907597 , version 1

Citer

Clémence Petit, François Valdivieso, Christophe Meunier, Jérémy Croquesel, Sylvie Pillon-Eymard, et al.. Microwave sintering of nuclear ceramics. ECerS16 - 16th Conference of the European Ceramic Society, Jun 2019, Turin, Italy. ⟨hal-04907597⟩

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