The control of exothermal reactions is an important issue for chemical process safety. Such reactions may produce a runaway after stirrer or cooling failure. This is accompanied by a temperature and pressure increase either because gaseous reaction products are generated or the reactor contents starts to boil. The reactors used for these reactions are amongst others equipped with trip systems. These may, for example, be based on the fast injection of a reaction inhibitor or the fast dumping of the reactor contents into a knock-out tank. The measures mentioned are active, i.e. they require a number of components (e.g. sensors,...