CBCP Part | - Annex 1,1
CONFIDENTIAL-
1.1-1
Annex 1.1
1
The International Nuclear Event Scale
Nuclear incidents/accidents, are assigned numerical leveis from 0 (no safety significance) to 7 (major nuclear accident) in a manner superùcially similar to the Richter scale for earthquakes.
This International-Nucicar-Event-Sealer was designed-by- a group- of experts convened jointly by the international Atomic Energy Agency and the Organisation for Economic Cooperation and Development-Nuclear Energy Agency. The underlying logic of the Scale involves taking into acount off-site and on-site effects of the accident and the extent to which the defence-in-depth provisions were degraded. The Scale itself is shown in Table I below. The derivation of the scale together with examples of accident classification is shown in Table 2 overleaf.
Table I - Underlying logic of the International Nudear Event Scale
Lever
Off-site impact
7
Major release:
(Major Accident)
On-site impact
Defence-in-depth degradation
(Senous Acadrat)
(Accident with off-site ndo)
4
(Acadent mainly in Installation)
3
(Senous Incident)
(Incident)
(Anomaly)
(Below scale)
Widespread health and Sivuonmental cilesis
Significant release: full implementation of local emergency plans
Limited release: partial implementation of local emergency plans
Minor release: public exposure of the order of prescribed limits
Very smail release: Public exposure at a fraction of prescribed limits
Severe core damage
Partial core damage. Acute health effects to werkers
Major contamination Overexposure of workers
Near accideat Loss of defence-in-death previsions
Incidents with potential
safety consequences
Deviations from authorizesi
functional domains
No safety significance
AX-01-01.00C (Mar-93)
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