Abstract: A high-impact force damping device is provided, particularly for the restraint of a pressurized-water reactor steam generator, to absorb and damp its impact force resulting from a break in its live steam output pipe line or reactor main pipe lines. The device is of the type relying on the plastic deformation of metal to absorb the impact force with a damping action preventing excessive rebound. To use this action, a substantially flat metal plate has one side supported by a suitable structure, and its other side provided with a bar having a width that is small as compared to that of the plate, this bar being made of metal that is harder than that of the metal plate, being in contact with the latter, and the bar being positioned to receive the impact force as by being positioned in the expected displacement path of the steam generator suffering a pipe line break accident. The plate and bar surfaces, at right angles to the direction of shock, are all mutually parallel with each other.