Energy Encyclopedia

Nuclear Energy · 6 min read · Energy Atlas Editorial

INES and Nuclear Accidents

The International Nuclear Event Scale ranks events. Three Mile Island, Chernobyl, and Fukushima are the reference severe accidents.

Overview

INES runs from 0 to 7. Three Mile Island (1979) was a core melt with limited off-site release (INES 5). Chernobyl (1986) and Fukushima Daiichi (2011) are INES 7. Causes differed: operator and design errors in a graphite reactor; earthquake-tsunami overwhelming a BWR site. Modern plants and regulation exist because of those lessons, not in spite of them.

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