Notkühlung

Notkühlung, in engineering and safety engineering, refers to emergency cooling measures designed to remove heat when normal cooling is unavailable or insufficient. Its primary purpose is to prevent overheating, fuel damage, or structural failure during accidents or transient events.

Notkühlungssysteme are widely used in safety-critical installations, notably in nuclear power plants, where they provide cooling of the reactor core and spent fuel pools after loss-of-coolant or loss of off-site power. Typical systems include emergency core cooling systems (ECCS) such as high-pressure coolant injection, low-pressure coolant injection, and accumulators, as well as containment spray and heat removal paths. These systems are usually designed with redundancy, diversity, and independence from the normal cooling circuits, and may be powered by electrical, chemical, or passive means.

Beyond nuclear plants, emergency cooling concepts appear in other industries, including chemical processing, data centers, and aerospace, where rapid heat removal is necessary to avert damage to equipment or personnel. In many contexts Notkühlung encompasses both active measures (pumps, valves, heat exchangers) and passive approaches (natural circulation, gravity-driven flow, stored coolant in fail-safe tanks).

Key considerations in Notkühlung design include ensuring sufficient coolant inventory, reliable power or fail-safe energy sources, rapid deployment, avoidance of hydrogen buildup, and maintenance of containment integrity. Regulatory frameworks emphasize system independence from normal operations, regular testing, and post-accident assessment.

Limitations include the finite amount of stored coolant, potential single-point failures, and challenges in severe accidents. Ongoing research focuses on passive safety features, improved reliability, and robust instrumentation to detect and mitigate cooling loss promptly.