RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone

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

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EXTERNAL HAZARDSEXTERNAL HAZARDS

ATAT

KOZLODUY AND BELENE NPP SITESKOZLODUY AND BELENE NPP SITES

Marin Kostov, Georgy Varbanov, Anton Andonov




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BackgroundBackground

•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 EXTERNAL HAZARDS AT KOZLODUY AND BELENE NPP SITESAND BELENE NPP SITES




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KASHIWAZAKI KARIWA NPP , M=6.6 2007KASHIWAZAKI KARIWA NPP , M=6.6 2007





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KASHIWAZAKI KARIWA NPPKASHIWAZAKI KARIWA NPP





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Sorce: WANO, March 14, 2011

SITE EVALUATION FOR NUCLEAR SITE EVALUATION FOR NUCLEAR POWER PLANTSPOWER PLANTS

FUKUSHIMA DISASTERFUKUSHIMA DISASTER




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NATURAL HAZARDS AFFECTING THE PLANT:NATURAL HAZARDS AFFECTING THE PLANT:

BEYOND DESIGN BASE EARTHQUAKE FOLLOWING BY BEYOND BEYOND DESIGN BASE EARTHQUAKE FOLLOWING BY BEYOND DESIGN BASE TZUNAMIDESIGN BASE TZUNAMI

RESULTED IN:RESULTED IN:

AUTOMATIC SEISMIC SCRAM OF THE REACTORSAUTOMATIC SEISMIC SCRAM OF THE REACTORS

TOTAL BLACK OUT OF THE STATIONTOTAL BLACK OUT OF THE STATION

TOTAL LOSS OF THE ULTIMATE HEAT SINKTOTAL LOSS OF THE ULTIMATE HEAT SINK

HYDROGEN BLAST IN THREE OF REACTOR BUILDINGSHYDROGEN BLAST IN THREE OF REACTOR BUILDINGS

TOTAL OR PARTIAL CORE DAMEGE IN THREE OF REACTORSTOTAL OR PARTIAL CORE DAMEGE IN THREE OF REACTORS

PARTIAL FUEL DAMAGE IN ONE SPENT FUEL POOL PARTIAL FUEL DAMAGE IN ONE SPENT FUEL POOL

UNCONTROLED RELEASE OF RADIOACTIVITYUNCONTROLED RELEASE OF RADIOACTIVITY





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MAIN REASONSMAIN REASONS

UNDERESTIMATION OF THE DESIGN BASE ACCOSIATED UNDERESTIMATION OF THE DESIGN BASE ACCOSIATED WITH THE NATURAL HAZARDS WITH THE NATURAL HAZARDS

INABILITY OF THE PLANT DESIGN TO MITIGATE THE EFFECTS INABILITY OF THE PLANT DESIGN TO MITIGATE THE EFFECTS OF THE BEYOND DESIGN BASE NATURAL HAZARDS OF THE BEYOND DESIGN BASE NATURAL HAZARDS

WEAK PREPEREDNESS TO CONTROL CRITICAL SITUATIONS WEAK PREPEREDNESS TO CONTROL CRITICAL SITUATIONS

STRESS TESTSSTRESS TESTS EVALUATION OF THE PLANT RESPONSE TO BEYOND DESIGNEVALUATION OF THE PLANT RESPONSE TO BEYOND DESIGN BASE NATURAL HAZARDS AND COMBINATION BETWEEN THEM BASE NATURAL HAZARDS AND COMBINATION BETWEEN THEM EVALUATION OF THE PLANT RESPONSE IN CONDITIONSEVALUATION OF THE PLANT RESPONSE IN CONDITIONS OF TOTAL BLACK OUT OF TOTAL BLACK OUT EVALUATION OF THE PLANT RESPONSE IN CONDITIONSEVALUATION OF THE PLANT RESPONSE IN CONDITIONS OF TOTAL ULTIMATE HEAT SINK OF TOTAL ULTIMATE HEAT SINK COMBINATION BETWEEN LOOP AND UHSCOMBINATION BETWEEN LOOP AND UHS





821 April 2023




921 April 2023

4.1-4.5

4.1-4.54.1-4.5

4.1-4.54.1-4.5

4.6-5.04.6-5.0

4.6-5.0

4.6-5.0

4.6-5.0

7.6-8.0 7.1-7.5 6.6-7.0 6.1-6.5 5.6-6.0 5.1-5.5 4.6-5.0 4.1-4.5

4.1-4.54.6-5.0

2 2 2 4 2 6 2 84 1

4 2

4 3

4 4




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SEISMIC DESIGN BASE FOR KOZLODUY AND BELENE NPP SITESSEISMIC DESIGN BASE FOR KOZLODUY AND BELENE NPP SITES

KNPPKNPPReturn period -10000 yearsPGAh = 0.2 gPGAh.l = 0.16 gPGAv = 0.1 gPGAv.l = 0.13 g

BNPPBNPPReturn period -10000 yearsPGAh = 0.24 gPGAv = 0.155 g





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SEISMIC DESIGN BASE FOR KNPP AND BNPPSEISMIC DESIGN BASE FOR KNPP AND BNPP

THE SEISMIC DESIGN BASES FOR BOTH SITES ARE THE SEISMIC DESIGN BASES FOR BOTH SITES ARE SIMILARSIMILAR

THE SEISMIC HAZARD FOR BOTH SITES IS DOMINATED BY THE SEISMIC HAZARD FOR BOTH SITES IS DOMINATED BY VRANCEA SOURCEVRANCEA SOURCE

THE SHAPES OF THE DBE RESPONSE SPECTRA ARE THE SHAPES OF THE DBE RESPONSE SPECTRA ARE SIMILAR DUE TO THE LONG PERIOD CONTRIBUTION OF SIMILAR DUE TO THE LONG PERIOD CONTRIBUTION OF VRANCEA SOURCEVRANCEA SOURCE

THE DBE PGA FOR BNPP SITE IS SLIGHTLY HIGHER DUE THE DBE PGA FOR BNPP SITE IS SLIGHTLY HIGHER DUE TO THE NEAREST LOCATION TO VRANCEA AND GORNA TO THE NEAREST LOCATION TO VRANCEA AND GORNA ORIAHOVITZA SOURCES ORIAHOVITZA SOURCES





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DETERMINISTIC SEISMIC HAZARD ASSESSMENTDETERMINISTIC SEISMIC HAZARD ASSESSMENT





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DETERMINISTIC SEISMIC HAZARD ASSESSMENT – MAX. SCENARIADETERMINISTIC SEISMIC HAZARD ASSESSMENT – MAX. SCENARIA





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Floods caused by natural high water levelFloods caused by natural high water levelFloods caused by failure of water control structuresFloods caused by failure of water control structuresFloods due to Floods due to failure of water control structures failure of water control structures

combined with extreme combined with extreme precipitation precipitation and wind wavesand wind waves

FLOODING OF THE KNPP AND BNPP SITESFLOODING OF THE KNPP AND BNPP SITES

KNPP BNPPSITE ELEVATION 35 m 28.5 mRIVER LEVEL PROB. 0.01% 32.23 m 26.38 mLEVEL OF PROTECTIVE DIKES 31-32 m 25-26 mBasic water discharge (m3/s) 10000 15000 10000 15000FAILURE OF IRON GATE1 AND IRON GATE2, W/O NIKOPOL-TURNU MAGURELE 31.78 32.14 24.94 25.79FAILURE OF IRON GATE1 AND IRON GATE 2, AND NUKOPOL-TURNU MAGURELE 34.56 34.26 26.88 26.67FAILURE OF IRON GATE1 AND IRON GATE 2, AND NUK.-T.M + SILISTRA- KALARASH 34.56 34.26 27.31 26.83EXTREME RAINS - PROBABILITY 0.01 - (expert judgment) 0.2 0.2WIND WAVES (expert judgment) 0.3 0.3





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FLOODING SCENARIA FOR THE KNPP SITE FLOODING SCENARIA FOR THE KNPP SITE





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FLOODING SCENARIA FOR THE BNPP SITE FLOODING SCENARIA FOR THE BNPP SITE





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FLOODIND SCENARIOSFLOODIND SCENARIOS

KNPP BNPP

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 siteTotal 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 penetrationsThe underground safety related structures are

protected against flooding by the design4. Damages in the national electric transmittal grid ? no5. Loss of some safety related structures? no

6. Clogging of the site surface water sewage system

during the extreme rains?7 Partial flooding of Kozloduy (town) Flooding of Belene (town)





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EVALUATION OF EXTERNAL HUMAN INDUCED EVENTSEVALUATION 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





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EVALUATION OF EXTERNAL HUMAN INDUCES EVENTSEVALUATION OF EXTERNAL HUMAN INDUCES EVENTS External blastsExternal blasts

KNPPKNPPThe risk from industrial and transport induced explosions is negligible. The Design Basis is conservatively assumedP=30kN/m2, t=1s

BNPPBNPPThe risk from industrial and transport induced explosions is negligible. The Design Basis is conservatively assumedP=30kN/m2, t=1s





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EVALUATION OF EXTERNAL HUMAN INDUCES EVENTSEVALUATION OF EXTERNAL HUMAN INDUCES EVENTS

KNPPKNPPStructural system:Single Post-tensioned RC Containment

Design loading:Mass =10t Velocity=750km/h (208m/s)

Beyond Design Loading:Not considered

BNPPBNPPStructural system:External RC ShellInternal Post-tensioned RC Containment

Design Loading:Mass=20tVelocity=215m/s

Beyond Design Loading:Boeing 747 with various velocities

Aircraft crashAircraft crash analysis – Design considerations for KNPP and BNPP analysis – Design considerations for KNPP and BNPP





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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)




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• 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%




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EVALUATION OF EXTERNAL HUMAN INDUCES EVENTSEVALUATION OF EXTERNAL HUMAN INDUCES EVENTS Aircraft crashAircraft crash analysis – 3D FE model analysis – 3D FE model




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Aircraft crashAircraft crash analysis – Definition of the load time functions analysis – Definition of the load time functionsEVALUATION OF EXTERNAL HUMAN INDUCES EVENTSEVALUATION OF EXTERNAL HUMAN INDUCES EVENTS

Riera’s methodRiera’s method Finite Element MethodFinite Element Method




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Impact Load Time Functions - Velocity Dependence

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7Time

Fo

rce

LPA_100m/s" LPA_110m/s" LPA_120m/s"

LPA_130m/s" LPA_140m/s" LPA_150m/s

LPA_160m/s Phantom RF-4_215m/s

Impact Load Time Functions for Large Passenger Airplane at V=155m/s - Mass Dependence

0 0.1 0.2 0.3 0.4 0.5 0.6

Time

Fo

rce

LPA_40%_MFC LPA_70%_MFC LPA_85%_MFC

LPA_100%_MFC Phantom_RF4_215m/s

Aircraft crashAircraft crash analysis – Definition of the load time functions analysis – Definition of the load time functionsEVALUATION OF EXTERNAL HUMAN INDUCES EVENTSEVALUATION OF EXTERNAL HUMAN INDUCES EVENTS

Influence of the impact velocityInfluence of the impact velocity Influence of the airplane massInfluence of the airplane mass




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EVALUATION OF EXTERNAL HUMAN INDUCES EVENTSEVALUATION OF EXTERNAL HUMAN INDUCES EVENTS Aircraft crashAircraft crash analysis – direct numerical simulation of airplane analysis – direct numerical simulation of airplane crash into Belene NPPcrash into Belene NPP




2721 April 2023

EVALUATION OF EXTERNAL HUMAN INDUCES EVENTSEVALUATION OF EXTERNAL HUMAN INDUCES EVENTS Aircraft crashAircraft crash analysis – 3D FE model analysis – 3D FE model




2821 April 2023

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




2921 April 2023

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.

Documents

RISK ENGINEERING, Ltd. Reliability – Safety - Management Engineering Services - Software Development 10, Vihren str., 1618 Sofia, Pavlovo, Bulgaria, phone