Kjerneavskekking

Kjerneavskekking, often translated as "core melting" or "core meltdown," is a severe accident that can occur in a nuclear power plant. It happens when the heat generated by the nuclear fission process, and subsequent radioactive decay, exceeds the cooling capacity of the reactor core. This leads to a significant rise in temperature, causing the fuel rods and their cladding to overheat.

If the cooling systems fail completely and for an extended period, the fuel rods can reach temperatures high enough to melt. This molten material, known as corium, can then burn through the reactor vessel and potentially breach the containment building. The integrity of the containment structure is crucial for preventing the release of radioactive materials into the environment.

The causes of kjerneavskekking are typically a combination of external events, such as natural disasters like earthquakes or tsunamis, and internal failures within the plant's systems. Loss of coolant, failure of emergency core cooling systems, and human error are common contributing factors.

The consequences of a kjerneavskekking can be severe, including widespread radioactive contamination, long-term health effects for exposed populations, and significant economic and environmental damage. The Chernobyl and Fukushima Daiichi disasters are prominent examples of nuclear accidents that involved kjerneavskekking. Safety regulations and plant design aim to prevent such events through multiple layers of redundancy and robust containment systems.