In case of a failure in the cooling or the electric supply and thus a stirrer break down, exothermic reactions can be self-accelerated caused by the heating-up of the reactor content, so that the danger of an unallowed rise in temperature and pressure occurs. In certain chemical processes (e. g. radical polymerization) a reaction-runaway can be stopped by the addition of inhibiting agents. With rapid and homogeneous distribution of the inhibiting agent by means of a fluid stored under pressure the endangered reactor can be controlled. In order to obtain design criteria for this safety device, the influence of relevant system parameters in the reaction and mixing behaviour has to be examined. Therefore experimental investigations and numerical simulations were made.