Passive autocatalytic recombiner

Passive autocatalytic recombiner (PAR) is a device that removes hydrogen from the containment of a nuclear power plant during an accident.

If the hydrogen is released from the reactor to the containment, it may get mixed with air and form a flammable or even explosive mixture.

The reaction of hydrogen and oxygen on the catalyst surface generates heat, and temperature in the recombiner reaches hundreds of degrees Celsius.

Hot steam is lighter than the air in the containment, so buoyancy is caused inside the recombiner, much like in a chimney.

[2] Manufacturers of passive autocatalytic recombiners include Framatome,[3] SNC-Lavalin (formerly Atomic Energy of Canada Ltd, AECL),[4] and German Siempelkamp-NIS.