Threat categories

Before any planning can begin, the practices and activities for which emergency response planning is necessary must be identified. Emergency planning could be different for each practice. However, this can be simplified by grouping practices into five threat categories, defined in Table I, each presenting common features in terms of the magnitude and timing of the hazard.

Information in the remainder of this publication is organized according to these “threat categories”. Threat categories I through III represent decreasing levels of threats at facilities and therefore decreasing emergency preparedness and response requirements. Threat category IV applies to threats and practices that can exist virtually anywhere and thus is the minimum level of threat assumed to exist everywhere. Threat category IV always applies to all jurisdictions, possibly along with other categories. Threat category V applies to the off-site areas where emergency preparations are warranted to address contamination resulting from a release from a facility in threat category I or II. These threat categories apply both to facilities or uses and to governmental jurisdictions for which various levels of preparedness are warranted. Section 2.2.5 provides help in determining the threat categories and Appendix 4 gives examples of the threat categories for different practices.

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TABLE I. FIVE CATEGORIES OF NUCLEAR AND RADIATION RELATED THREATS FOR THE PURPOSES OF APPLYING THE METHOD [2]

Threat category

Description

I Facilities, such as nuclear power plants, for which on-site events³ (including very low probability events) are postulated that could give rise to severe deterministic health effects⁴ off the site, or for which such events have occurred in similar facilities.

II Facilities, such as some types of research reactors, for which on-site events³ are postulated that could give rise to doses to people off the site that warrant urgent protective actions in accordance with international standards⁵, or for which such events have occurred in similar facilities. Threat category II (as opposed to threat category I) does not include facilities for which on-site events (including very low probability events) are postulated that could give rise to severe deterministic health effects off the site, or for which such events have occurred in similar facilities.

III Facilities, such as industrial irradiation facilities, for which on-site events are postulated that could give rise to doses that warrant or contamination that warrants urgent protective actions on the site, or for which such events have occurred in similar facilities.

Threat category III (as opposed to threat category II) does not include facilities for which events are postulated that could warrant urgent protective action off the site, or for which such events have occurred in similar facilities

IV Activities that could give rise to a nuclear or radiological emergency that could warrant urgent protective actions in an unforeseeable location. These include non-authorized activities such as activities relating to dangerous sources obtained illicitly. They also include transport and authorized activities involving dangerous mobile sources such as industrial radiography sources, radiothermal generators or nuclear powered satellites.

Threat category IV represents the minimum level of threat, which is assumed to apply for all States and jurisdictions.

V Activities not normally involving sources of ionizing radiation, but which yield products with a significant likelihood⁶ of becoming contaminated as a result of events at facilities in threat categories I or II, including such facilities in other States, to levels necessitating prompt restrictions on products in accordance with international standards.

3 Involving an atmospheric or aquatic release of radioactive material or external exposure (such as due to a loss of shielding or a criticality event) that originates from a location on the site.

4 Doses in excess of those for which intervention is expected to be undertaken under any circumstances; see Schedule IV of Ref. [3], reproduced in Appendix 2. See Glossary under definition of deterministic health effects.

5 Schedule V of Ref. [3], reproduced in Appendix 1.

6 Conditional on the occurrence of a significant release of radioactive material from a facility in threat category I or II.

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Table II summaries the emergency preparedness arrangements that should be in place for each threat category.

TABLE II SUMMARY OF THE EMERGENCY PREPAREDNESS ARRANGEMENTS BY THREAT CATEGORY

Threat Category I and II

Operator Off-site officials for the emergency zones Arrangements to promptly: classify an emergency;

mitigate the emergency; notify and recommend protective actions off the site consistent with international guidance;

protect those on site; obtain off-site assistance; conduct environmental monitoring near the facility; and assist off-site officials in keeping the public informed.

Arrangements to promptly: implement urgent protective actions within the emergency zones; control consumption of contaminated food within the food restriction planning radius; provide emergency services to the facility; provide medical treatment to contaminated or overexposed victims;

tell the public and media in plain language of the risk, and of the action they should take; and monitor and respond to inappropriate public reactions.

Threat Category III

Operator Off-site officials – near the facility Arrangements to promptly: classify emergency; protect

those on site; inform off-site officials; obtain off-site assistance; conduct environmental monitoring near the facility to ensure that there are no off-site risks; and assist off-site officials in keeping the public informed.

Arrangements to promptly provide emergency services;

give medical treatment to contaminated or overexposed victims; confirm there are no off-site impacts; tell the public and media in plain language of the risk and of the action they should take; and monitor and respond to inappropriate public reactions.

Threat Category IV Operator

(Dangerous mobile source) Off-site officials

(National level) Arrangements to promptly: recognize an emergency, take

action to protect the people nearby, mitigate the emergency, inform off-site officials of the risk; and provide technical assistance to off-site officials if needed.

Arrangements to: inform (in advance) medical practitioners, scrap metal dealers and border crossings on the recognition and response to a radiological emergency;

promptly make decisions on protective actions consistent with international guidance, assess and respond to a limited radiological emergency, tell the public and media in plain language of the risk, and of the actions they should take;

report transnational emergencies to the IAEA; respond to IAEA notifications; and request IAEA assistance when needed.

Threat Category V Farmers and food producers in

food restriction planning radius

Off-site officials

(Food restriction planning radius) Arrangements to promptly respond to official instructions

to protect the food/water supply and control potentially contaminated food/water.

Arrangements to issue instructions to protect the food/water supply and control potentially contaminated food/water, consistent with international standards.

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