Nuclear power for the classroom
Nuclear Accidents

Nuclear plant accidents and the scale to measure them
See also
Japan nuclear disaster 2011



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Nuclear accidents:
   Safety news
   Scale of nuclear accidents

See also:
Nuclear reactors and meltdowns
Japan nuclear disaster 2011

See also our Japan earthquakes and tsunamis 2011 page


The Fukushima nuclear plant in Japan appears to have had a partial meltdown, not "a meltdown".  For an explanation of the distinction see Meltdown 101: What is a nuclear reactor meltdown? (


Nuclear accidents:

Information   Japan: Nuclear crisis raised to Chernobyl level (
The severity rating of the Fukushima nuclear accident ahs been raised from 6 to 7.
For more on the scale on which nuclear accidents are measured, see below.

List of nuclear power plant accidents (

Comparing Japan to Chernobyl Nuclear Disaster (
Advice about the Chernobyl nuclear disaster took days to emerge, and many of the people who helped died as a result.

Safety news   WNN: Regulation  and safety (
From World Nuclear News.
Images   The Worst Nuclear Disasters (

Top 5 Worst Nuclear Disasters (

Videos   Chernobyl - Nuclear Meltdown (
"Great Blunders in History." 5-minute preview of a 22-minute video. (Requires installation of software to watch the full video.)

Issues to discuss   Nuclear Power and Children's Health: What You Can Do [pdf] (
Symposium proceedings. Includes environmental impact, disasters waiting to happen, accidents that have happened, terrorism, nuclear waste issues.


INES - Scale of nuclear accidents

Scale of nuclear accidents
(The International Nuclear and Radiological Event Scale)

Level 7 Major release of radioactive material with widespread health and environmental effects Chernobyl, Ukraine, 1986
Fukushima, Japan, 2011
Level 6 Significant release of radioactive material likely to require implementation of planned countermeasures Kyshtym, Russia, 1957
Level 5 Limited release of radioactive material. Severe damage to reactor core. Three Mile Island, US, 1979
Windscale, UK, 1957
Level 4 Minor release of radioactive material. Fuel melt or damage. Tokaimura, Japan, 1999
Saint Laurent des Eaux, France, 1980
Level 3 Exposure in excess of 10 times the statutory annual limit for workers. Severe contamination but with a low probability of significant public exposure. Sellafield, UK, 2005
Vandellos, Spain, 1989
Level 2 Exposure of a member of the public in excess of 10mSv (average annual dose is 1mSv). Exposure of a worker in excess of the annual limit. Significant contamination within the facility. Atucha, Argentina, 2005
Cadarache, France, 1993
Forsmark, Sweden, 2006
Level 1 Overexposure of a member of public. Minor safety problems. Low activity lost or stolen source or device.  

Below Scale (Level 0): No safety significance.

Based on information from the IAEA: IAEA - INES [pdf] with Japan 2011 added.




Last updated 6 Dec 2013
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