International Nuclear and Radiological Event Scale

International Nuclear and Radiological Event Scale
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Name	International Nuclear and Radiological Event Scale
Abbr	INES
Introduced	1990
Administered by	International Atomic Energy Agency
Scope	Nuclear and radiological events
Website	International Atomic Energy Agency

Contents

Overview

INES was developed jointly by the International Atomic Energy Agency and the Nuclear Energy Agency of the Organisation for Economic Co-operation and Development to harmonize public communication after events like Chernobyl disaster and Three Mile Island accident. It assigns ratings used by institutions such as European Commission and World Health Organization to compare significance across incidents involving organizations like Rosatom, Westinghouse Electric Company, Areva and facilities such as Fukushima Daiichi Nuclear Power Plant, Kashiwazaki-Kariwa Nuclear Power Plant, and research reactors at institutions like Oak Ridge National Laboratory and Institut Laue–Langevin. National authorities including French Nuclear Safety Authority, Nuclear Regulation Authority (Japan), Federal Service for Ecological, Technological and Nuclear Supervision (Rostekhnadzor), and Canadian Nuclear Safety Commission apply INES in public advisories and policy briefs alongside technical reports from International Commission on Radiological Protection.

INES uses a seven-level ordinal scale (Levels 1–7) plus Level 0 and "Below Scale" to denote significance; key comparators include Chernobyl disaster (Level 7) and Three Mile Island accident (Level 5). The scale distinguishes between International Atomic Energy Agency definitions for radiological dispersion device incidents, reactor core degradation, and transport accidents involving entities like International Maritime Organization and International Air Transport Association. Each level references metrics used by institutes such as United Nations Scientific Committee on the Effects of Atomic Radiation and World Health Organization for health impact, environmental contamination, and release magnitude, enabling comparison with releases historically documented at sites like Mayak Production Association and Tokaimura nuclear accident.

Classification uses technical criteria including off-site radiological impact, on-site worker exposure, degradation of defense-in-depth, and cross-border consequences assessed by International Atomic Energy Agency teams often in liaison with European Union civil protection mechanisms and national bodies like the Nuclear Regulatory Commission and Atomic Energy Council (Taiwan). Application involves event appraisal, provisional rating, and final confirmation; stakeholders include operators such as EDF Energy, Kansai Electric Power Company, and research facilities at Lawrence Livermore National Laboratory, with data inputs from radiation monitoring networks run by Comisión Nacional de Energía Atómica and Federal Office for Radiation Protection (Germany). INES categorization guides communication alongside international frameworks like the Convention on Early Notification of a Nuclear Accident and Convention on Assistance in the Case of a Nuclear Accident or Radiological Emergency.

INES has been invoked for events ranging from Chernobyl disaster (Level 7) and Fukushima Daiichi nuclear disaster (Level 7) to Three Mile Island accident (Level 5), the Windscale fire (rated historically), and transport incidents involving radioactive sources such as those reported by International Atomic Energy Agency and national regulators including Nuclear Regulation Authority (Japan) and Canadian Nuclear Safety Commission. Other notable INES applications include Tokaimura nuclear accident and contamination episodes at facilities linked to Mayak Production Association; agencies including European Commission and World Health Organization have used INES ratings to inform cross-border health advisories and trade responses involving entities like World Trade Organization.

Critics from institutions like World Nuclear Association, independent researchers associated with Greenpeace International and academic groups at Massachusetts Institute of Technology and Imperial College London argue that INES simplifies complex technical differences between releases, reactor accidents, and radiological source events; commentators cite inconsistent national application by authorities such as Rosatom and Tokyo Electric Power Company and request clearer quantitative thresholds analogous to those used by International Commission on Radiological Protection and United Nations Scientific Committee on the Effects of Atomic Radiation. Proposals for reform reference lessons from Chernobyl disaster and Fukushima Daiichi nuclear disaster and suggest integration with monitoring frameworks employed by European Commission and World Health Organization.

Category:Nuclear safety