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PRESENT DAY EOPS AND SAMG - WHERE DO WE GO FROM HERE?

  • Received : 2012.03.23
  • Published : 2012.04.25

Abstract

The Fukushima-Daiichi accident shook the world, as a well-known plant design, the General Electric BWR Mark I, was heavily damaged in the tsunami, which followed the Great Japanese Earthquake of 11 March 2011. Plant safety functions were lost and, as both AC and DC failed, manoeuvrability of the plants at the site virtually came to a full stop. The traditional system of Emergency Operating Procedures (EOPs) and Severe Accident Management Guidelines (SAMG) failed to protect core and containment, and severe core damage resulted, followed by devastating hydrogen explosions and, finally, considerable radioactive releases. The root cause may not only have been that the design against tsunamis was incorrect, but that the defence against accidents in most power plants is based on traditional assumptions, such as Large Break LOCA as the limiting event, whereas there is no engineered design against severe accidents in most plants. Accidents beyond the licensed design basis have hardly been considered in the various designs, and if they were included, they often were not classified for their safety role, as most system safety classifications considered only design basis accidents. It is, hence, time to again consider the Design Basis Accident, and ask ourselves whether the time has not come to consider engineered safety functions to mitigate core damage accidents. Associated is a proper classification of those systems that do the job. Also associated are safety criteria, which so far are only related to 'public health and safety'; in reality, nuclear accidents cause few casualties, but create immense economical and societal effects-for which there are no criteria to be met. Severe accidents create an environment far surpassing the imagination of those who developed EOPs and SAMG, most of which was developed after Three Mile Island - an accident where all was still in place, except the insight in the event was lost. It requires fundamental changes in our present safety approach and safety thinking and, hence, also in our EOPs and SAMG, in order to prevent future 'Fukushimas'.

References

  1. "Safety of Nuclear Power Plants: Design", SSR 2/1, IAEA, Vienna, 2012 (replacing NS-R-1).
  2. Dr. Nils J. Diaz (former chairman USNRC), "Reflections on Fukushima", 19th International Conference on Nuclear Engineering (ICONE19), Osaka, Japan, October 24-25, 2011
  3. Oddbjorn Sandervag, Wiktor Frid, "Swedish regulatory aspects on severe accident management implementation", OECD Specialist Meeting on Severe Accident Management Implementation, Niantic, CT, USA, June 1995
  4. Harri Tuomisto, "In Pursuit of Consistency and Completeness in the Severe Accident Assessment and Management", OECD Specialist Meeting on Severe Accident Management Implementation, Niantic, CT, USA, June 1995
  5. "GPR/RSK Proposal for a Common Safety Approach for Future Pressurised Water Reactors", Federal Agency for Radiation Protection (German: Bundesamt fur Strahlenschutz), Salzgitter, Germany, May 1993.
  6. "Safety and Pressure Integrity Classification Criteria for Light Water Reactors", American National Standard, ANSI/ANS 98.14, 2011.
  7. "Safety Classification of Structures, Systems and Components in Nuclear Power Plants", Draft Safety Guide DS367, IAEA, Vienna, 2009.
  8. "B.5.b Phase 2 & 3 Submittal Guideline, Rev. 2", ERIN Engineering & Research, NEI 06-12, December 2006.
  9. Bill Borchardt, "USNRC Fukushima Lessons-Learned Actions", IAEA International Experts Meeting on Reactor and Spent Fuel Safety in the Light of the Accident at the Fukushima-Daiichi NPP, IAEA Vienna, 19 - 22 March 2012.
  10. Caroline Lavarenne, "Main Conclusions of the French NPP Stress Tests, 'A Need for a Hardened Safety Core' ", IAEA International Experts Meeting on Reactor and Spent Fuel Safety in the Light of the Accident at the Fukushima- Daiichi NPP, IAEA Vienna, 19 - 22 March 2012.
  11. "Recommendations for Enhancement of Reactor Safety, The USNRC Near-Term Task Force (NTTF) Review of Insights from the Fukushima-Daiichi Accident", USNRC, July 2011.
  12. Michel Vidard, "EdF Nuclear Fleet, Post-Fukushima Safety Assessments," EdF, presentation to the meeting mentioned in ref. [14].
  13. IAEA Ministerial Conference, 20-24 June 2011, Vienna, Austria.
  14. "IAEA Consultant's Meeting on Updating Accident Management Guides on Safety Aspects of Lessons Learnt from Fukushima Accidents: Embedded Workshop on Harmonization and Integration between SAMG and EOP", IAEA, 14-16 November 2011, Hotel Intercity (Spapia), Daejeon, Korea, Working Material, November 2011.
  15. "ENSREG Stress Test", www.ensreg.eu, May 2011.
  16. "External Event Design Safety Margin Evaluation Program", IAEA International Seismic Safety Centre, September 2011.
  17. M. El-Shanawany, I. Kuzmina, A. Lyubarskyi, "Systematic Assessment of Robustness of Nuclear Power Plants against the Impact of Extreme Events", TSO Forum, Vienna, Austria, 18-20 January 2012.
  18. R. J. Lutz, Jr. and M. A. Lucci, "Modelling Post-Core Damage Operator Actions in the PRA", PSA'08 Conference, Knoxville, TN, USA, September 2008.
  19. Marcel Slootman, "Use of the Software Module SPRINT in the Netherlands for the Prediction of the Source Term", OECD ISAMM 2009, Bottstein, Switzerland, 2009.
  20. Yong Man Song, "The Demonstrative Assessment of Possible Candidates for Controlling Containment Hydrogen and Fission Product Release in Korean PHWR Plant", at workshop ref. [14].