INES: International Nuclear and Radiological Event Scale

The International Nuclear and Radiological Event Scale is an international assessment standard for so-called events in nuclear facilities (nuclear power plants, storage facilities, etc.), but also generally for all events in connection with radioactive substances. INES serves to inform the public in a simple and comprehensible way about the safety-relevant effects of such events. 

The scale consists of seven levels that are used to classify the safety significance of a specific event. Level 1 describes a so-called "anomaly", level 7 a "major accident". Level 2 and 3 events are referred to as "incident" and ”serious incident”. All events classified higher are considered "accidents". The safety-related significance increases with each level. Over the years, it has also become common practice to classify events with no or little safety significance as "Level 0".