[en] Full text of publication follows: Hydrogen peroxide is one of the main molecular oxidants produced by water radiolysis by the spent nuclear fuel radiation. In previous works, we have studied the effect of this oxidising agent on the UO₂ in order to develop an oxidation/dissolution mechanism under conditions relatively close to the ones expected in a deep geological repository. However, the effect of parameters such as temperature and pressure, which may have a significant effect in the whole mechanism, has not been studied. In the present work we have developed and used a continuously stirred tank flow-through reactor to determine the kinetics of dissolution of UO₂ in the presence of H₂O₂ (from 1 x 10^-5 to 8 x 10^-5 mol dm^-3) and as a function of hydrostatic pressure (from 1 to 32 bar) and temperature (from 20 to 50 deg. C). In the output flow we measured both uranium and hydrogen peroxide concentrations until the system reached a steady state condition. At that point, we used the uranium concentrations, the flow rate and the total area of solid inside the reactor to calculate the rates of dissolution (mol x m^-2 x s^-1). The results obtained have been evaluated using a multi-parametric analysis. The equation obtained, fitted reasonably well the data obtained at different experimental conditions. In addition, the dissolution rates predicted by that equation have been compared with some values obtained in our laboratory in both continuous an batch studies. When the experimental conditions of those studies were entered in the multi-parametric equation, the predicted values calculated were in good agreement with the experimental ones. Finally, an activation energy of 35 ± 9 kJ x mol^-1 was determined for the temperature range studied. This value falls in the range of energies found in the literature for spent nuclear fuel, non-irradiated uranium dioxide and uraninites (20-60 kJ x mol^-1). (authors)