A magnetic resonance examination system, comprising - a superconducting main magnet surrounding an examination region and arranged to generate a main magnetic field in the examination region, and - a magnetic field gradient system arranged to selectively cause alternating gradient magnetic fields in the examination region, said magnetic field gradient system being disposed outside of the main magnet, characterized in that the magnetic resonance examination system further comprises - a predicting device, adapted to calculate, in a timely and spatially resolved manner, the expected AC losses in the main magnet due to the gradient magnetic fields of an imaging protocol intended for use and/or which is actually used and to subsequently apply the thermal conductivity equation to predict the heat load and/or the resulting temperature distribution in the main magnet, - a preventing device, adapted to prevent, based on the predicted behavior of the main magnet, overheating of the main magnet due to AC losses and as a result prevent the main magnet from quenching, and thus ensure stable operation of the main magnet, wherein overheating of the main magnet is prevented by either: (i) rejecting the execution of an imaging protocol that would result in overheating of the main magnet, (ii) allowing the execution of a modified imaging protocol only which was modified such that overheating is avoided during execution of the modified imaging protocol, or (iii) allocating sufficient cooling power to a cooling system of the main magnet such that overheating is avoided during the execution of the imaging protocol. - a superconducting main magnet surrounding an examination region and arranged to generate a main magnetic field in the examination region, and - a magnetic field gradient system arranged to selectively cause alternating gradient magnetic fields in the examination region, said magnetic field gradient system being disposed outside of the main magnet, - a predicting device, adapted to calculate, in a timely and spatially resolved manner, the expected AC losses in the main magnet due to the gradient magnetic fields of an imaging protocol intended for use and/or which is actually used and to subsequently apply the thermal conductivity equation to predict the heat load and/or the resulting temperature distribution in the main magnet, - a preventing device, adapted to prevent, based on the predicted behavior of the main magnet, overheating of the main magnet due to AC losses and as a result prevent the main magnet from quenching, and thus ensure stable operation of the main magnet, wherein overheating of the main magnet is prevented by either: (i) rejecting the execution of an imaging protocol that would result in overheating of the main magnet, (ii) allowing the execution of a modified imaging protocol only which was modified such that overheating is avoided during execution of the modified imaging protocol, or (iii) allocating sufficient cooling power to a cooling system of the main magnet such that overheating is avoided during the execution of the imaging protocol. (i) rejecting the execution of an imaging protocol that would result in overheating of the main magnet, (ii) allowing the execution of a modified imaging protocol only which was modified such that overheating is avoided during execution of the modified imaging protocol, or (iii) allocating sufficient cooling power to a cooling system of the main magnet such that overheating is avoided during the execution of the imaging protocol.