[en] The results are presented of an evaluation of the power-cooling-mismatch and irradiation effects test data on fuel rod cladding behavior. Cladding embrittlement resulting from the high temperature oxidizing reactions with the coolant and the fuel was evaluated and comparisons with failure criteria are presented. The in-pile data are correlated with room temperature embrittlement criteria based on the fraction of remaining beta-phase, the total extent of oxidation, and the mean oxygen concentration near saturation in the beta-phase. The applicability of other failure criteria are discussed. The results of this study show that the in-pile data are most consistent with criteria based on the mean oxygen content in the beta-phase, which suggests the critical effect of time and temperature upon the ultimate cladding oxygen distribution and on the extent of cladding embrittlement