Nuclear and radiation accidents and incidents involving HEU or plutonium trafficking: A nuclear meltdown is a severe nuclear reactor accident that results in reactor core damage from overheating. It has been defined as the accidental melting of the core of a nuclear reactor, and refers to the core's either complete or partial collapse. A core melt accident occurs when the heat generated by a nuclear reactor exceeds the heat removed by the cooling systems to the point where at least one nuclear fuel element exceeds its melting point. This differs from a fuel element failure, which is not caused by high temperatures. A meltdown may be
Behavior of nuclear fuel during a reactor accident to form two molecules of carbon monoxide. This is one of the processes which limits the working life of this type of reactor. In a water-cooled reactor the action of radiation on the water (radiolysis) forms hydrogen peroxide and oxygen. These can cause stress corrosion cracking of metal parts which include fuel cladding and other pipework. To mitigate this hydrazine and hydrogen are injected into a BWR or PWR primary cooling circuit as corrosion inhibitors to adjust the redox properties of the system. A review of recent developments on this topic has been published. In a loss-of-coolant accident (LOCA) it