During a LOCA, fuel claddings in a pressurised water reactor can be subjected to severe thermomechanical loadings. The temperature of the claddings can reach more than 1000°C and the pressure difference between the inside and the outside of the cladding can exceed 100 bar. During normal operation of the reactor, the claddings are corroded by primary water. In accidental situations, the oxidation of the cladding is strongly influenced by its temperature. This work aims to study the thermomechanical behavior of the cladding under such loading conditions, considering its corrosion state. Several coupled physics affect the behavior of the cladding under such conditions. These include the coupling between metal and oxide creep, oxygen diffusion into the metal, oxidation and oxide damage. On one hand, oxidation tests are carried out at 750°C and 820°C in order to study the oxidation of the claddings without external mechanical loadings. At these temperatures, a cubic kinetics is observed for oxide growth. The growth kinetics of the oxygen enriched metal layer (a(O)) is consistent with the extrapolation of the correlation established by other studies, from tests performed at higher temperatures (T>900°C). This result was not obvious because the material undergoes a phase transformation between 820°C and 900°C. The metal oxygen diffusion coefficient identified at 750°C and 820°C are consistent with previous work. On the other hand, semi-integral ballooning tests involving the coupling between mechanical loading and high temperature oxidation are carried out. These tests demonstrate the strengthening role of the pre-oxide, high temperature oxide and a(O) with respect to creep. This reinforcing role is strongly reduced once the oxide layer progressively cracks finally leading ballooning onset.