1. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 1 EXTERNAL HAZARDS AT AT KOZLODUY AND BELENE NPP SITES Marin Kostov, Georgy Varbanov, Anton Andonov

2. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 2 Background Fukushima – accident, error or logical result? Fukushima – accident, error or logical result? Stress test – Why it’s needed? Stress test – Why it’s needed? The consequences of Fukushima? The consequences of Fukushima? EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES

3. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 3 KASHIWAZAKI KARIWA NPP, M=6.6 2007 EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES

4. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 4 KASHIWAZAKI KARIWA NPP EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES

5. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 5 Sorce: WANO, March 14, 2011 SITE EVALUATION FOR NUCLEAR POWER PLANTS FUKUSHIMA DISASTER

6. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 6 NATURAL HAZARDS AFFECTING THE PLANT:  BEYOND DESIGN BASE EARTHQUAKE FOLLOWING BY BEYOND DESIGN BASE TZUNAMI RESULTED IN: AUTOMATIC SEISMIC SCRAM OF THE REACTORS 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 EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES

7. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 7 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 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 EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES

8. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 8 10 September 2015

9. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 9 10 September 2015

10. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 10 SEISMIC DESIGN BASE FOR KOZLODUY AND BELENE NPP SITES KNPP Return period -10000 years PGA h = 0.2 g PGA h.l = 0.16 g PGA v = 0.1 g PGA v.l = 0.13 g BNPP Return period -10000 years PGA h = 0.24 g PGA v = 0.155 g EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES

11. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 11 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 EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES

12. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 12 DETERMINISTIC SEISMIC HAZARD ASSESSMENT EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES

13. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 13 DETERMINISTIC SEISMIC HAZARD ASSESSMENT – MAX. SCENARIA EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES

14. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 14  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 FLOODING OF THE KNPP AND BNPP SITES KNPPBNPP SITE ELEVATION35 m28.5 m RIVER LEVEL PROB. 0.01%32.23 m26.38 m LEVEL OF PROTECTIVE DIKES31-32 m25-26 m Basic water discharge (m 3 /s)10000150001000015000 FAILURE OF IRON GATE1 AND IRON GATE2, W/O NIKOPOL-TURNU MAGURELE31.7832.1424.9425.79 FAILURE OF IRON GATE1 AND IRON GATE 2, AND NUKOPOL-TURNU MAGURELE34.5634.2626.8826.67 FAILURE OF IRON GATE1 AND IRON GATE 2, AND NUK.-T.M + SILISTRA- KALARASH34.5634.2627.3126.83 EXTREME RAINS - PROBABILITY 0.01 - (expert judgment)0.2 WIND WAVES (expert judgment)0.3 EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES

15. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 15 FLOODING SCENARIA FOR THE KNPP SITE EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES

16. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 16 FLOODING SCENARIA FOR THE BNPP SITE EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES

17. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 17 FLOODIND SCENARIOS KNPPBNPP 1. Flooding of the site (if HPC N – TM is constructed without reconstruction of the dikes) Flooding of the site ? – the safety margin is 0.6 m 2. Partial flooding of the surroundings and isolation of the site Total flooding of the surroundings and isolation of the site 3. Increase of the underground water level with res- pective risks for the safety related underground structures and penetrations The underground safety related structures are protected against flooding by the design 4.Damages in the national electric transmittal grid ?no 5.Loss of some safety related structures?no 6. Clogging of the site surface water sewage system during the extreme rains? 7Partial flooding of Kozloduy (town)Flooding of Belene (town) EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES

18. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 18 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 EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES

19. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 19 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 SITE EVALUATION FOR NUCLEAR POWER PLANTS

20. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 20 EVALUATION OF EXTERNAL HUMAN INDUCES EVENTS 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 Aircraft crash analysis – Design considerations for KNPP and BNPP EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITES

21. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 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. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 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. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 23 SITE EVALUATION FOR NUCLEAR POWER PLANTS EVALUATION OF EXTERNAL HUMAN INDUCES EVENTS Aircraft crash analysis – 3D FE model

24. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 24 Aircraft crash analysis – Definition of the load time functions EVALUATION OF EXTERNAL HUMAN INDUCES EVENTS Riera’s method Finite Element Method

25. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 25 Aircraft crash analysis – Definition of the load time functions EVALUATION OF EXTERNAL HUMAN INDUCES EVENTS Influence of the impact velocity Influence of the airplane mass

26. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 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. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 27 10 September 2015 EVALUATION OF EXTERNAL HUMAN INDUCES EVENTS Aircraft crash analysis – 3D FE model

28. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 28 10 September 2015 Conclusions 1.KNPP and BNPP have adequate seismic design base that corresponds to the current standards 2.There is available seismic margin and cliff-edge effects are not probable 3.The external flooding hazard is properly assessed and there is available design margin 4.Anthropogenic hazards are properly assessed and there is available margin. The BNPP is designed also for the largest available aircraft impact (malevolent) 5.The tornado hazard in Bulgaria is negligible

29. RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone +359 2 8089 501, fax +359 2 9507 751 29 10 September 2015 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.