Page 190 - AERB

INTERNATIONAL NUCLEAR AND RADIOLOGICAL EVENT SCALE (INES)

Level/ Descriptor Nature of the Events Examples
7 Major release: Widespread health and environmental Chernobyl NPP, USSR (now
MAJOR ACCIDENT effects requiring implementation of planned and extended in Ukraine), 1986
countermeasures. Fukushima NPP, Japan, 2011
6 Significant release: Likely to require full implementation of Kyshtym Reprocessing Plant,
SERIOUS planned countermeasures. Russia, 1957
ACCIDENT
Limited release: Likely to require partial implementation of some Windscale Pile, UK, 1957
5 planned countermeasures. Three Mile Island, NPP, USA,
Severe damage to reactor core / several deaths from radiation. 1979
ACCIDENT Goiania, Brazil, 1987
WITH WIDER Release of large quantities of radioactive material within an
installation with a high probability of significant public exposure.
CONSEQUENCES This could arise from a major criticality accident or fire.
Minor release of radioactive material unlikely to result in Tokaimuro, Japan, 1999
4 implementation of planned countermeasures other than local Saint-Laurent des Eaux NPP,
food controls. France, 1980
ACCIDENT Fuel melt or damage to fuel resulting in more than 0.1% release Fleurus, Belgium, 2006
WITH LOCAL of core inventory. Mayapuri, India, 2010
CONSEQUENCES At least one death from radiation/release of significant quantities
of radioactive material within an installation with a high
probability of significant public exposure.
Near accident of an NPP with no safety provisions remaining.
3 Highly radioactive sealed source lost or stolen/misdelivered Vandellos NPP, Spain, 1989
without adequate radiation procedures in place to handle it. Ikitelli, Turkey, 1999
SERIOUS
INCIDENT Exposure rates of more than 1 Sv/h in an operating area. Sellafield, UK, 2005
Severe contamination in an area not expected by design, with a Yanango, Peru,1999
low probability of significant public exposure.
Exposure in excess of ten times the statutory annual limit for
workers/ Non-lethal deterministic health effect (e.g. burns) from
radiation.
Significant failures in safety provisions but with no actual
2 consequences. Forsmark, Sweden, 2006
Exposure of member of public in excess of 10 mSv/exposure of a
INCIDENT worker in excess of the statutory annual limits/ Radiation level in Atucha, Argentina, 2005
an operating area of more than 50 mSv/h.
Significant contamination within the facility into an area not
expected by design.
Found highly radioactive sealed orphan source, device or
transport package with safety provisions intact / inadequate
packaging of highly radioactive material sealed source.
Minor problems in safety components with significant defence in Breach of operating limits
1 depth remaining/ low activity lost or stolen radioactive source, at a nuclear facility/ theft of
device or transport package. radioactive source
ANOMALY Overexposure of member of public in excess of statutory limits.

0
DEVIATIONS No safety significance
BELOW SCALE