The dissolution of helium in La-doped UO2 as a surrogate of hypo-stoichiometric UO2

Highlights: • Infusion technique was used to introduce He in La-doped UO₂ samples. • La-doped UO₂ samples were used to study hypo-stoichiometry effect on He solubility. • Dissolved He quantities slightly increase with increasing La content of the samples. - Abstract: In this work, the dissolution of helium in La-doped UO₂ samples was studied by helium infusion in an autoclave followed by thermal desorption (laser heating) coupled to mass spectrometer systems for the determination of helium release rate and the total helium quantity. Lanthanum was chosen as a dopant in UO₂ to study the effect of hypo-stoichiometry on helium solubility together with the impurity effect. Comparison of the dissolved He quantity from the samples with different La content showed that the dissolved He quantity slightly increases with increasing oxygen vacancy concentration in the samples.