During the start-up regime of the IBR-2M power fluctuations appear, which the Automatic Regulator system dampens. Their origin is not completely clear, however it is known that the major reactivity sources are from design – respectively the OPO and DPO reflectors: their axial fluctuations towards the active zone and their relative phase of intersecting each other facing the center of the active zone. A neuromorphic solution is sought to anticipate (5-10 s) such fluctua-tions. We present encouraging preliminary results obtained with a Non-linear Autoregressive Ex-ogenous (NARX) neural network, the main features of the fluctuations being anticipatable.