Abstract: Method for estimating an axial power imbalance in a nuclear reactor, comprising the following steps: obtaining a reactor power setpoint, for each variable of a plurality of variables of the reactor, determining a sequence of the variable, the sequence representing estimated future variations of the variable, determining a sequence of the axial power imbalance, by taking into account the sequences of the plurality of variables of the reactor, the determination of the sequence of the axial power imbalance using a machine learning module that is trained beforehand on historic reactor data.