Difference between revisions of "International Nuclear Event Scale"

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[[Image:ChernobylPlant.jpg|Impression of the 1986 exploded Chernobyl NPP unit 4|thumb|right]]
 
[[Image:ChernobylPlant.jpg|Impression of the 1986 exploded Chernobyl NPP unit 4|thumb|right]]
After the Chernobyl accident, the International Nuclear Event Scale (INES) has enhanced reporting on events at nuclear power plants.<ref name="stuk_ines">http://www.stuk.fi/ydinturvallisuus/ydinvoimalaitokset/vakavuusasteikko/en_GB/asteikko/ - December 10, 2010</ref>
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After the Chernobyl accident, the International Nuclear Event Scale (INES) has enhanced reporting on events at nuclear power plants<ref name="stuk_ines">http://www.stuk.fi/ydinturvallisuus/ydinvoimalaitokset/vakavuusasteikko/en_GB/asteikko/ as at December 10, 2010</ref>. It was implemented in 1990<ref name="smh_worldscale" />. The UN's International Atomic Energy Agency (IAEA) describes INES as a tool for "promptly communicating to the public in consistent terms" what a nuclear episode means<ref name="smh_worldscale" />. It has three factors: radioactivity releases to the public; barriers against radiation at a nuclear site; and civil-defence measures<ref name="smh_worldscale">http://www.smh.com.au/environment/energy-smart/world-scale-for-rating-nuclear-accidents-20110412-1dc3m.html as at April 12, 2011</ref>.
  
In the INES the events are roughly divided into deviations, incidents and accidents. The events are classified on the Scale at seven levels. The lower levels (1-3) are termed incidents. The upper levels (4-7) are termed accidents. The events which have no safety significance are classified as level 0/below scale. They are termed deviations. The lower levels consists of anomalies, incidents and serious incidents. The upper levels are comprised of accidents without significant off-site risk, accidents with off-site risk, serious accidents and major accidents.<ref name="stuk_ines"/>
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In the INES the events are roughly divided into deviations, incidents and accidents<ref name="stuk_ines"/>. The events are classified on the Scale at seven levels<ref name="stuk_ines"/>. Each increase in level on the scale indicates a roughly 10-fold increase in severity<ref name="smh_worldscale" />.
  
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The lower levels (1-3) are termed incidents<ref name="stuk_ines"/>. The upper levels (4-7) are termed accidents<ref name="stuk_ines"/>. The events which have no safety significance are classified as level 0/below scale<ref name="stuk_ines"/>. They are termed deviations<ref name="smh_worldscale" /><ref name="stuk_ines"/>. The lower levels consists of anomalies, incidents and serious incidents<ref name="stuk_ines"/>. The upper levels are comprised of accidents without significant off-site risk, accidents with off-site risk, serious accidents and major accidents<ref name="stuk_ines"/>.
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== Description of INES levels ==
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* '''INES 0''': Events known as "deviations" that have no safety significance<ref name="smh_worldscale" />
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* '''INES 1''': Anomaly<ref name="smh_worldscale" />
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:Minor problem with safety components at a nuclear facility, but significant safety margin remaining
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* '''INES 2''': Incident<ref name="smh_worldscale" />
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:Radiation levels in an operating area of a nuclear facility of more than 50 millisieverts (mSv) per hour. Exposure of a member of the public to radiation in excess of 10 mSv, exposure of a worker in excess of statutory annual limits.
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* '''INES 3''': Serious Incident<ref name="smh_worldscale" />
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:Severe contamination in an area of a facility, with non-lethal injuries such as radiation burns. Low probability of significant public exposure.
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* '''INES 4''': Accident with local consequences<ref name="smh_worldscale" />
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: Partial meltdown or damage to fuel, release of significant quantities of radioactive material within an installation. No counter-measures likely to be needed other than local food controls.
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* '''INES 5''': Accident with wider consequences<ref name="smh_worldscale" />
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:Severe damage to reactor core, large quantities of radioactive material released within a site. Limited release of material to the wider environment, requiring implementation of some planned countermeasures.
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* '''INES 6''': Serious accident<ref name="smh_worldscale" />
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:Significant release of radioactive material likely to require implementation of planned countermeasures.
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* '''INES 7''': Major accident<ref name="smh_worldscale" />
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:Major release of radioactive material with widespread health and environmental effects, requiring implementation of planned and extended countermeasures.
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== Examples of INES accidents ==
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'''INES 7''':
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* 1986 Chernobyl (UA)<ref name="smh_worldscale" /> - meltdown and explosion
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'''INES 6''':
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* 1957 Kyshtym (RUS) - explosion at a waste tank<ref name="smh_worldscale" />
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'''INES 5''':
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* 1957 Windscale (UK) - fire nuclear plant<ref name="smh_worldscale" />
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* 1979 Three Mile Island (USA) - meltdown<ref name="smh_worldscale" />
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== Other concepts ==
 
In Germany accidents up to INES level 4 are called ''GAU'' (German for '''g'''rößter '''a'''nzunehmender '''U'''nfall) refering to the US-American concept of the ''maximum credible accident'' a nuclear plant needed to be prepared for. Accidents of higher level are called ''Super-GAU'' as their impacts are even bigger than the biggest accidents the plant concepts necessarily have to deal with.<ref>http://de.wikipedia.org/w/index.php?title=Auslegungsst%C3%B6rfall&oldid=86847110 as at March 24, 2011</ref>.  
 
In Germany accidents up to INES level 4 are called ''GAU'' (German for '''g'''rößter '''a'''nzunehmender '''U'''nfall) refering to the US-American concept of the ''maximum credible accident'' a nuclear plant needed to be prepared for. Accidents of higher level are called ''Super-GAU'' as their impacts are even bigger than the biggest accidents the plant concepts necessarily have to deal with.<ref>http://de.wikipedia.org/w/index.php?title=Auslegungsst%C3%B6rfall&oldid=86847110 as at March 24, 2011</ref>.  
  
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== Atomic catastrophe information network ==
 
The IAEA maintains an information exchange network between the countries participating in the use of the Scale. Reports on the events belonging to the level 2 or above it are submitted to the IAEA through the NEWS (Nuclear Event Web-based System). The IAEA should have information on the level of the event in its disposal within 24 hours.<ref name="stuk_ines"/>
 
The IAEA maintains an information exchange network between the countries participating in the use of the Scale. Reports on the events belonging to the level 2 or above it are submitted to the IAEA through the NEWS (Nuclear Event Web-based System). The IAEA should have information on the level of the event in its disposal within 24 hours.<ref name="stuk_ines"/>
  
 
The event level is defined in the country where the event takes place.<ref name="stuk_ines"/>
 
The event level is defined in the country where the event takes place.<ref name="stuk_ines"/>
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== Further information ===
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* http://gnssn.iaea.org/regnet/Pages/INES.aspx
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* http://www.iaea.org/Publications/Factsheets/English/ines.pdf
  
  

Revision as of 12:38, 12 April 2011

Impression of the 1986 exploded Chernobyl NPP unit 4

After the Chernobyl accident, the International Nuclear Event Scale (INES) has enhanced reporting on events at nuclear power plants[1]. It was implemented in 1990[2]. The UN's International Atomic Energy Agency (IAEA) describes INES as a tool for "promptly communicating to the public in consistent terms" what a nuclear episode means[2]. It has three factors: radioactivity releases to the public; barriers against radiation at a nuclear site; and civil-defence measures[2].

In the INES the events are roughly divided into deviations, incidents and accidents[1]. The events are classified on the Scale at seven levels[1]. Each increase in level on the scale indicates a roughly 10-fold increase in severity[2].

The lower levels (1-3) are termed incidents[1]. The upper levels (4-7) are termed accidents[1]. The events which have no safety significance are classified as level 0/below scale[1]. They are termed deviations[2][1]. The lower levels consists of anomalies, incidents and serious incidents[1]. The upper levels are comprised of accidents without significant off-site risk, accidents with off-site risk, serious accidents and major accidents[1].

Description of INES levels

  • INES 0: Events known as "deviations" that have no safety significance[2]
  • INES 1: Anomaly[2]
Minor problem with safety components at a nuclear facility, but significant safety margin remaining
  • INES 2: Incident[2]
Radiation levels in an operating area of a nuclear facility of more than 50 millisieverts (mSv) per hour. Exposure of a member of the public to radiation in excess of 10 mSv, exposure of a worker in excess of statutory annual limits.
  • INES 3: Serious Incident[2]
Severe contamination in an area of a facility, with non-lethal injuries such as radiation burns. Low probability of significant public exposure.
  • INES 4: Accident with local consequences[2]
Partial meltdown or damage to fuel, release of significant quantities of radioactive material within an installation. No counter-measures likely to be needed other than local food controls.
  • INES 5: Accident with wider consequences[2]
Severe damage to reactor core, large quantities of radioactive material released within a site. Limited release of material to the wider environment, requiring implementation of some planned countermeasures.
  • INES 6: Serious accident[2]
Significant release of radioactive material likely to require implementation of planned countermeasures.
  • INES 7: Major accident[2]
Major release of radioactive material with widespread health and environmental effects, requiring implementation of planned and extended countermeasures.


Examples of INES accidents

INES 7:

  • 1986 Chernobyl (UA)[2] - meltdown and explosion

INES 6:

  • 1957 Kyshtym (RUS) - explosion at a waste tank[2]

INES 5:

  • 1957 Windscale (UK) - fire nuclear plant[2]
  • 1979 Three Mile Island (USA) - meltdown[2]


Other concepts

In Germany accidents up to INES level 4 are called GAU (German for größter anzunehmender Unfall) refering to the US-American concept of the maximum credible accident a nuclear plant needed to be prepared for. Accidents of higher level are called Super-GAU as their impacts are even bigger than the biggest accidents the plant concepts necessarily have to deal with.[3].


Atomic catastrophe information network

The IAEA maintains an information exchange network between the countries participating in the use of the Scale. Reports on the events belonging to the level 2 or above it are submitted to the IAEA through the NEWS (Nuclear Event Web-based System). The IAEA should have information on the level of the event in its disposal within 24 hours.[1]

The event level is defined in the country where the event takes place.[1]


Further information =