EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES

1. EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES Marin Kostov, Georgy Varbanov, Anton Andonov

2. EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES • Background • Fukushima – accident, error or logical result? • Stress test – Why it’s needed? • The consequences of Fukushima?

3. EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES KASHIWAZAKI KARIWA NPP , M=6.6 2007

4. EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES KASHIWAZAKI KARIWA NPP

5. SITE EVALUATION FOR NUCLEAR POWER PLANTS Sorce: WANO, March 14, 2011 FUKUSHIMA DISASTER

6. EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES • NATURAL HAZARDS AFFECTING THE PLANT: • BEYOND DESIGN BASE EARTHQUAKE FOLLOWING BY BEYOND DESIGN BASE TZUNAMI • RESULTED IN: • AUTOMATIC SEISMIC SCRAM OF THE REACTORS • TOTAL BLACK OUT OF THE STATION • TOTAL LOSS OF THE ULTIMATE HEAT SINK • HYDROGEN BLAST IN THREE OF REACTOR BUILDINGS • TOTAL OR PARTIAL CORE DAMEGE IN THREE OF REACTORS • PARTIAL FUEL DAMAGE IN ONE SPENT FUEL POOL • UNCONTROLED RELEASE OF RADIOACTIVITY

7. EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES • MAIN REASONS • UNDERESTIMATION OF THE DESIGN BASE ACCOSIATED WITH THE NATURAL HAZARDS • INABILITY OF THE PLANT DESIGN TO MITIGATE THE EFFECTS OF THE BEYOND DESIGN BASE NATURAL HAZARDS • WEAK PREPEREDNESS TO CONTROL CRITICAL SITUATIONS • STRESS TESTS • EVALUATION OF THE PLANT RESPONSE TO BEYOND DESIGN BASE NATURAL HAZARDS AND COMBINATION BETWEEN THEM • EVALUATION OF THE PLANT RESPONSE IN CONDITIONS OF TOTAL BLACK OUT • EVALUATION OF THE PLANT RESPONSE IN CONDITIONS OF TOTAL ULTIMATE HEAT SINK • COMBINATION BETWEEN LOOP AND UHS

10. EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES SEISMIC DESIGN BASE FOR KOZLODUY AND BELENE NPP SITES KNPP Return period -10000 years PGAh = 0.2 g PGAh.l = 0.16 g PGAv = 0.1 g PGAv.l = 0.13 g BNPP Return period -10000 years PGAh = 0.24 g PGAv = 0.155 g

11. EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES SEISMIC DESIGN BASE FOR KNPP AND BNPP • THE SEISMIC DESIGN BASES FOR BOTH SITES ARE SIMILAR • THE SEISMIC HAZARD FOR BOTH SITES IS DOMINATED BY VRANCEA SOURCE • THE SHAPES OF THE DBE RESPONSE SPECTRA ARE SIMILAR DUE TO THE LONG PERIOD CONTRIBUTION OF VRANCEA SOURCE • THE DBE PGA FOR BNPP SITE IS SLIGHTLY HIGHER DUE TO THE NEAREST LOCATION TO VRANCEA AND GORNA ORIAHOVITZA SOURCES

12. EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES DETERMINISTIC SEISMIC HAZARD ASSESSMENT

13. EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES DETERMINISTIC SEISMIC HAZARD ASSESSMENT – MAX. SCENARIA

14. EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES FLOODING OF THE KNPP AND BNPP SITES • Floods caused by natural high water level • Floods caused by failure of water control structures • Floods due to failure of water control structures combined with extreme precipitation and wind waves

15. EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES FLOODING SCENARIA FOR THE KNPP SITE

16. EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES FLOODING SCENARIA FOR THE BNPP SITE

17. EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES FLOODIND SCENARIOS

18. EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES EVALUATION OF EXTERNAL HUMAN INDUCED EVENTS • Chemical explosions due to industrial accidents • Explosion during the transportation of explosive materials • Release of toxic and/or explosive gases • Release of radioactive gases • Forest or turf fire

19. SITE EVALUATION FOR NUCLEAR POWER PLANTS EVALUATION OF EXTERNAL HUMAN INDUCES EVENTS External blasts KNPP The risk from industrial and transport induced explosions is negligible. The Design Basis is conservatively assumed P=30kN/m2, t=1s BNPP The risk from industrial and transport induced explosions is negligible. The Design Basis is conservatively assumed P=30kN/m2, t=1s

20. EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES EVALUATION OF EXTERNAL HUMAN INDUCES EVENTS Aircraft crash analysis – Design considerations for KNPP and BNPP KNPP Structural system: Single Post-tensioned RC Containment Design loading: Mass =10t Velocity=750km/h (208m/s) Beyond Design Loading: Not considered BNPP Structural system: External RC Shell Internal Post-tensioned RC Containment Design Loading: Mass=20t Velocity=215m/s Beyond Design Loading: Boeing 747 with various velocities

21. Air traffic • Group A – large airplanes with weight more than 330t (A380, A340, B747 and B777); • Group B – intermediate size airplanes with weight between 150t and 330t (A300, A330, A350, B767, B707); • Group C – small airplanes with weight less than 150t (A321, B737)

22. Airplanes taking off from and landing on Bulgarian airports: • Group A: 1% • Group B: 1% • Group C: 98% • Airplanes in Bulgarian sky – flying over, taking off and landing: • Group A: 3,8% • Group B: 15,1% • Group C: 81,1% • Airplanes flying over in 70km zone: • Group A: 4,6% • Group B: 17,5% • Group C: 77,9%

23. SITE EVALUATION FOR NUCLEAR POWER PLANTS EVALUATION OF EXTERNAL HUMAN INDUCES EVENTS Aircraft crash analysis – 3D FE model

24. EVALUATION OF EXTERNAL HUMAN INDUCES EVENTS Aircraft crash analysis – Definition of the load time functions Riera’s method Finite Element Method

25. EVALUATION OF EXTERNAL HUMAN INDUCES EVENTS Aircraft crash analysis – Definition of the load time functions Influence of the airplane mass Influence of the impact velocity

26. SITE EVALUATION FOR NUCLEAR POWER PLANTS EVALUATION OF EXTERNAL HUMAN INDUCES EVENTS Aircraft crash analysis – direct numerical simulation of airplane crash into Belene NPP

27. EVALUATION OF EXTERNAL HUMAN INDUCES EVENTS Aircraft crash analysis – 3D FE model

28. Conclusions • KNPP and BNPP have adequate seismic design base that corresponds to the current standards • There is available seismic margin and cliff-edge effects are not probable • The external flooding hazard is properly assessed and there is available design margin • Anthropogenic hazards are properly assessed and there is available margin. The BNPP is designed also for the largest available aircraft impact (malevolent) • The tornado hazard in Bulgaria is negligible

29. Conclusions 6. The extreme combination of EQ, flooding, extreme wind, extreme cold and hot weather have to be studied 7. The risk of failure of all surrounding infrastructure due to earthquake, flooding or anthropogenic actions have to be studied 8. The preparedness for extreme hazards have to be improved and trained 9. The extreme hazard mitigation measures have to be constant and continuous effort.