Evaluation of Oxygen Stoichiometry during the Sintering of (U, Pu)O$_2$ Fuel

S. Vaudez (1) , J. Léchelle (1) , S. Berzati (1)

1 CEA-DES (ex-DEN) - CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire)

For ceramics such as (U, Pu)O$_2$, diffusion phenomena occurring during sintering are affected by oxygen content of the atmosphere. The latter imposes the nature and the concentration of structural defects which govern diffusion mechanisms inside the material. The oxygen partial pressure, pO$_2$, of the sintering gas in equilibrium with MOX pellets needs to be precisely controlled; otherwise a large dispersion in critical parameters for fuel manufacturing could be induced. Among them, the oxygen over metal ratio (O/M) after sintering defines many properties of the fuel in operation (thermal conductivity, mechanical properties,). SFR fuels have to be hypostoichiometric with a O/M ratio close to 1,98. To achieve this, it is crucial to understand the relation between the sintering atmosphere and the fuel along the thermal cycle. In this study, oxygen potential monitoring of the sintering gas was carried out by measuring oxygen partial pressure (pO$_2$) at the outlet of a dilatometer by means of a zirconia probe.

Mots clés: MOX; Frittage pO$_2$

Domaines: Physique Nucléaire Théorique [nucl-th]; Physique Nucléaire Expérimentale [nucl-ex]

S. Vaudez, J. Léchelle, S. Berzati. Evaluation of Oxygen Stoichiometry during the Sintering of (U, Pu)O$_2$ Fuel. Plutonium Futures: The Science 2014, ANS, Sep 2014, Las Vegas, United States. ⟨cea-02979279⟩