Thermal runaway

Thermal runaway refers to a situation where an increase in temperature changes the conditions in a way that causes a further increase in temperature leading to a destructive result.

Chemical engineering

In chemical engineering, thermal runaway is a process by which an exothermic reaction goes out of control, often resulting in an explosion.

Thermal runaway is said to occur when the reaction rate increases due to an increase in temperature, causing a further increase in temperature and hence a further increase in the reaction rate. It is a fruitiful source of industrial accidents, most notably the 1984 explosion of a Union Carbide plant in Bhopal, India that produced methyl isocyanate.

Thermal runaway is most often caused by failure of the cooling system for a reactor vessel, with addition of components in the wrong order also being a common cause.

Many chemical production facilities are designed with high-volume emergency venting to limit the extent of injury and property damage when such accidents occur.

Electronics

Some types of transistors (notably germanium based bipolar transistors) increase significantly in current gain as they increase in temperature. Depending on the design of the circuit this increase in current gain can increase the current flowing through the transistor and with it the power dissipation. This causes a further increase in current gain. Eventually one of two things will happen, either the circuit will stabilize or the transistor will be destroyed by the heat.