At Chalk River in the 1950s
Nuclear power plant accidents: listed and ranked since 1952
How many nuclear power plants have had accidents and incidents? Get the full list and find out how they're ranked
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The explosions and nuclear fuel rods melting at Japan's Fukushima nuclear power plant, following the Sendai earthquake and tsunami last week, have caused fears of what will happen next. Today Japan's nuclear safety agency has raised the nuclear alert level for Japan from four to five - making it two levels lower than the Chernobyl disaster in 1986.
We have identified 33 serious incidents and accidents at nuclear power stations since the first recorded one in 1952 at Chalk River in Ontario, Canada.
Read more at www.guardian.co.uk
The information is partially from the International Atomic Energy Authority - which, astonishingly, fails to keep a complete historical database - and partially from reports. Of those we have identified, six happened in the US and five in Japan. The UK and Russia have had three apiece.