[en] A new system is proposed for protecting against reactor accidents of loss of coolant type. The dangerous consequences of the break of the primary coolant circuit can be prevented or at least damped by the new system. The pipes of the primary coolant circuit are surrounded by a damping tube system, which is connected to the other components of the primary circuit by pressure limiting valves. The parts of the outer tube system are connected by further pipes. Displacement and deviation compensators are built into the system. Between the primary coolant and the coating tubes several ribs are applied to dump the flow of the coolant erupting at the accidental break of the primary coolant tube and to reduce its pressure. The new system is relatively cheap and can be installed subsequently to the primary circuits constructed earlier. (D.Gy.)