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International Nuclear and Radiological Event Scale (INES) - 12 April 2011

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International Nuclear and Radiological Event Scale (INES) - 12 April 2011

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International Nuclear and Radiological Event Scale (INES) - 12 April 2011

  1. The International Nuclear and Radiological Event Scale INES Denis Flory Deputy Director General Department of Nuclear Safety and Security International Atomic Energy Agency
  2. What is INES? <ul><li>International event rating scale with the aim of communicating to the public the safety significance of nuclear and radiological events </li></ul><ul><li>Provides criteria for rating any event associated with the transport, storage and use of radioactive material </li></ul><ul><li>Jointly developed in 1990 by the IAEA and OECD/NEA </li></ul><ul><li>INES communication network comprises over 70 Member States </li></ul>
  3. Understanding the INES Scale Chernobyl (1986) Kyshtym (1957 ) TMI (1979) Tokaimura (1999) Vandellos (1989) Forsmark (2006) Breach of operating limits www-news.iaea.org
  4. Using the INES Scale: three criteria <ul><li>Impact on people and environment </li></ul><ul><ul><li>Activity released or dose received </li></ul></ul><ul><li>Impact on radiological barriers and controls (former on-site impact) </li></ul><ul><ul><li>The severity of the event inside the site of a facility and the potential harm to the public </li></ul></ul><ul><li>Degradation in “Defence in Depth” </li></ul><ul><ul><li>Looking at failures in safety provisions to determine how close the event was to causing actual consequences </li></ul></ul>
  5. General Description of Criteria At Level 4/5: fuel damage and radiological barrier damage occurs At Level 6/7: significant radiological releases occur
  6. <ul><li>&quot;All safety activities, whether organizational, behavioural or equipment related, are subject to layers of overlapping provisions , so that if a failure should occur it would be compensated for or corrected without causing harm to individuals or the public at large...” </li></ul><ul><ul><ul><li>Basic Safety Principles for Nuclear Power Plants (INSAG-3) </li></ul></ul></ul><ul><li>The strategy for defence in depth is twofold: first, to prevent accidents and second, if prevention fails, to limit the potential consequences of accidents and to prevent their evolution to more serious conditions. </li></ul>Defence in Depth Explained
  7. Defence in Depth Illustrated <ul><li>The fuel matrix </li></ul><ul><li>The fuel cladding </li></ul><ul><li>The boundary of the Reactor Coolant System </li></ul><ul><li>The Containment System </li></ul><ul><li>Mitigation of the radiological consequences of significant external releases of radioactive materials </li></ul><ul><ul><li>Quality Assurance </li></ul></ul><ul><ul><li>Control systems (alarms) </li></ul></ul><ul><ul><li>Safety culture </li></ul></ul><ul><ul><li>Accident management </li></ul></ul><ul><ul><li>Emergency planning </li></ul></ul>P H Y S I C A L P R O C E D U R A L Based on INSAG-10: Defence in Depth in Nuclear Safety
  8. Defence in Depth Rated <ul><li>Initiator approach: </li></ul><ul><li>The occurrence that c hallenges the safety systems, e.g. reactor trip, loss of coolant, loss of off-site power </li></ul><ul><li>Power reactor while at power; hot shutdown; start up conditions </li></ul><ul><li>Safety layer approach : </li></ul><ul><li>How many layers of safety still remain </li></ul><ul><li>Power reactors during shutdown; cold shutdown </li></ul><ul><li>Fuel cycle facilities, research reactors, accelerators, etc </li></ul><ul><li>Identify how close the event was to causing actual consequences by looking at the safety provisions: </li></ul><ul><ul><li>What has failed? and What is left? </li></ul></ul>
  9. INES Event Rating Form Fukushima-Daiichi units 1,2 and 3 Provisionally Rated on 18 th March at level 5
  10. INES Event Rating Form Fukushima-Daiichi units 1,2 and 3 Provisionally Rated on 12 th April at Level 7
  11. How to Communicate INES Events <ul><li>NEWS: www-news.iaea.org </li></ul><ul><ul><li>Events rated at INES level 2 and above </li></ul></ul><ul><ul><li>Events attracting international public interest </li></ul></ul><ul><ul><li>IAEA hosts and administrates the system </li></ul></ul><ul><ul><li>Event reports are filed and updated by the participating countries </li></ul></ul>
  12. Questions & Answers <ul><li>Thank you for your time. </li></ul>

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