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Cernavoda, Iunie 2011 OVERVIEW ON PERFORMANCE & PERSPECTIVE IONEL BUCUR, Ph.D. CERNAVODA NPP SITE DIRECTOR & SNN SA CNO JUNE 2011 NUCLEARELECTRICA S.A.

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Presentation on theme: "Cernavoda, Iunie 2011 OVERVIEW ON PERFORMANCE & PERSPECTIVE IONEL BUCUR, Ph.D. CERNAVODA NPP SITE DIRECTOR & SNN SA CNO JUNE 2011 NUCLEARELECTRICA S.A."— Presentation transcript:

1 Cernavoda, Iunie 2011 OVERVIEW ON PERFORMANCE & PERSPECTIVE IONEL BUCUR, Ph.D. CERNAVODA NPP SITE DIRECTOR & SNN SA CNO JUNE 2011 NUCLEARELECTRICA S.A.

2 Cernavoda, Iunie 2011 NUCLEARELECTRICA NUCLEARELECTRICA HEADQUARTERS CNE CERNAVODA BRANCH FCN PITESTI BRANCH

3 Cernavoda, Iunie 2011 OUR MISSION CNE CERNAVODA  TO PRODUCE “CLEAN” ELECTRICAL AND THERMAL POWER IN RESPECT OF NUCLEAR SAFETY CONDITIONS AND ECONOMICAL EFFICIENCY;  TO CONSTANTLY TRANSFORM THE WORKING ENVIRONMENT SUCH AS THE PLANT PERSONNEL FEEL THE PRIDE AND THE PRIVILEGE TO BE PART OF CERNAVODA NPP.

4 Cernavoda, Iunie 2011 OUR VISION  CERNAVODA NPP – A PLANT AMONG THE FIRST 25 NUCLEAR POWER PLANT IN THE WORLD BY THE END OF 2013;  MEET ALL REQUIREMENTS & CONDITIONS IMPOSED BY EUROPEAN COMMUNITY FOR NUCLEAR INDUSTRY;  MANAGEMENT OF RADIOACTIVE WASTE AND DECOMMISIONIG ACCORDING TO LEGAL PROVISIONS AND EUROPEAN PRACTICES;  BE INVOLVED IN U3 & U4 COMPLETION & OPERATION;  SUPPORT THE DEVELOPMENT OF LOCAL COMMUNITY AND MAINTAIN A PERMANENT DIALOGUE WITH LOCAL COMMUNITY IN ORDER TO INCREASE THE ACCEPTANCE OF NUCLEAR ENERGY;

5 Cernavoda, Iunie 2011 PLANT PERFORMANCE PRODUCTION OF ELECTRICAL POWER DELIVERED TO THE NATIONAL GRID U1&U2 (MWh)

6 Cernavoda, Iunie 2011 ELECTRICAL POWER PRODUCTION IN 2010 – BREAKDOWN BY RESOURCE TYPE

7 Cernavoda, Iunie 2011 GROSS CAPACITY FACTOR U1&U2 (%)

8 Cernavoda, Iunie 2011 COMPARED WITH OTHER SIMILAR CANDU UNITS, THE CAPACITY FACTOR SIS, AT THE END OF MARCH 2011 WAS: SINCE IN SERVICE 1. CERNAVODA 295,3% 2. WOLSONG 394,9% 3. WOLSONG 494,9% 4. WOLSONG 293,8% 5. QINSHAN 591,3% 6. QINSHAN 490.2% 7. CERNAVODA 189,4% 8. DARLINGTON 386.3% 9. DARLINGTON 485,7% 10. EMBALSE84,9% …………………………………………………………………………………….. AT THE END OF MARCH 2011, CERNAVODA 1 WAS SITUATED ON 7 TH PLACE SIS OUT OF 27 PHWR OPERATING UNITS AND UNIT 2 ON 1 ST PLACE SIS.

9 Cernavoda, Iunie 2011 IMPACT ON PEOPLE & ENVIRONMENT CUMMULATED RELEASES OF RADIOACTIVE EFFLUENTS U1&U2 (μ Sv)

10 Cernavoda, Iunie 2011 m 3 VOLUME OF RADIOACTIVE WASTE U1&U2 (m 3 ) TOTAL: AVERAGE ANNUAL DESIGN VALUE:30 m 3 / unit

11 Cernavoda, Iunie 2011 COLLECTIVE RADIATION EXPOSURE U1&U2 (man·mSv/ unit)

12 Cernavoda, Iunie 2011 INTERNATIONAL COOPERATION In 2007 – 2011 CERNAVODA NPP PARTICIPATED ACTIVELY IN OUTSIDE ORGANIZATION MISSIONS, PROVIDING EXPERTS FOR:  5 OSART MISSIONS ORGANIZED BY IAEA IN BELGIUM, GERMANY, JAPAN, SWEDEN, AND CZECH REPUBLIC;  17 WANO PEER REVIEWS AT CANADIAN (2 – BRUCE, GENTILLY, 2 - DARLINGTON), SPAIN (TRILLO) AND USA (THREE MILES ISLAND, CATAWBA, PALISADES, COOPER, RIVER BEND, SEEBROOK, DIABLO CANYON, SEQUOYAH, AND BRUNSWICK) NUCLEAR POWER PLANTS. THE SMOOTH TRANSFER OF KNOWLEDGE AND EXPERIENCE BETWEEN TEAM MEMBERS AND STAFF OF THE EVALUATED PLANT IS ENSURED FOLLOWING THESE MISSIONS, ALLOWING EACH PERSON TO LEARN FROM THE EXPERIENCE OF THE OTHERS AND TO ALIGN TO THE BEST INTERNATIONAL PRACTICE IN THE FIELD. THE FINAL GOAL IS TO OBTAIN A SAFE AND RELIABLE OPERATION OF THE NUCLEAR POWER PLANTS.

13 Cernavoda, Iunie 2011 MAJOR OBJECTIVES FOR 2011  PLANT GROSS CAPACITY FACTOR  95% (CONTINUOUS OPERATION BETWEEN PLANNED OUTAGES);  NUMBER OF REPORTABLE EVENTS  8;  DECREASE OF INTERNAL DOSE WEIGHT IN THE TOTAL DOSE (  20%);  CONSOLIDATION OF THE ORGANIZATION & LEADERSHIP (“ALL THAT IS GOOD”);  EFFICIENT UTILIZATION OF HUMAN RESOURCES AND OPTIMIZATION OF THE NUMBER OF EMPLOYEES IN THE ORGANIZATION;  OPTIMIZATION OF O&M COSTS & WAREHOUSE STOCKS;  SUCCESSFULLY PASS THE “STRESS TESTS”.

14 Cernavoda, Iunie 2011 WANO PEER REVIEW – NOVEMBER 2010  PERFORMANCE HAS IMPROVED IN MANY AREAS BECAUSE OF STATION LEADERSHIP PROVIDING CLEAR VISION AND DIRECTION;  IDENTIFIED PROBLEMS ARE SYSTEMATICALLY RESOLVED AND IN SEVERAL CASES PREVIOUS WEAKNESSES HAVE BECOME AREAS WORTHY OF INDUSTRY EMULATION;  THE NUCLEAR AND INDUSTRIAL SAFETY CULTURES ARE HEALTHY;  THE WORKFORCE CLEARLY UNDERSTANDS THAT NUCLEAR SAFETY TAKES PRIORITY OVER PRODUCTION AND HAS DEMONSTRATED AN EXEMPLARY INDUSTRIAL SAFETY ACCIDENT RATE OVER THE REVIEW PERIOD; .EQUIPMENT PERFORMANCE AND A CULTURE INTOLERANT OF EQUIPMENT FAILURES HAVE IMPROVED OVER THE REVIEW PERIOD.

15 Cernavoda, Iunie 2011  PROVIDE AROUND 1675 JOBS AS SNN EMPLOYEES AND, ON THE LONG TERM, AROUND 800 JOBS FOR CONTRACTOR COMPANIES;  PROVIDE HEATING FOR MORE THAN 60% OF CERNAVODA HABITANTS (APPROX Gcal/2010) AT THE LOWEST PRICE IN THE COUNTRY;  PROVIDE A CONSTANT INCOME TO THE LOCAL BUDGET, WHICH CONTINUOUSLY INCREASED. ONLY IN 2010 A TOTAL AMOUNT OF 12,9 MIL LEI REPRESENTING TAXES, DUTIES, AND OTHER OBLIGATION WERE PAID;  MORE THAN 600 LODGINGS WERE PROVIDED TO ACCOMMODATE 725 EMPLOYEES; SOCIAL & ECONOMICAL EFFECTS  STARTING 1992 AN IMPORTANT PROGRAM IS BEING DEVELOPED “EMERGENCY SOCIAL PROGRAM FOR IMPROVING LIFE CONDITIONS IN CERNAVODA”;

16 Cernavoda, Iunie 2011  11 MAJOR PROJECTS WERE FINALIZED AT THE END OF 2010, IN AMOUNT OF 50 MILLION EURO:  MINIMARKET (“FOISOR”);  KINDERGARTEN;  DOMESTIC WATER STATION (PUMPING & TREATMENT);  ROAD CONNECTIONS AND FIRST TRAFFIC LIGHTS IN INTERSECTIONS;  HEATING SYSTEM AND THERMAL STATIONS;  “ST. MARIA” BRIDGE WHICH ASSURES ROAD ACCESS TO CERNAVODA RAILWAY STATION AND TO FETESTI – CERNAVODA HIGHWAY;  THEORETICAL HIGHSCHOOLS;  HOSPITAL WITH 100 BEDS AND DISPENSARY;  SEWAGE TREATMENT PLANT;  A POTABLE WATER WELL.  PRESENTLY TWO PROJECTS ARE ON GOING:  YOUTH RECREATION CENTER;  EXTENSION OF HEATING SYSTEM FOR CERNAVODA TOWN.

17 Cernavoda, Iunie 2011  FURTHER SUPPORT WAS PROVIDED TO LOCAL COMMUNITY FOR PEOPLE AFFECTED BY JULY 2010 FLOODS:  WATER DISCHARGE AND SLUDGE CLEANING FROM THE STREETS;  BUILDING AND EQUIPPING A COMPLEX OF TEMPORARY LODGINGS ( LEI);  CLOTHING AND BEDDING (36119 LEI).  BEDDING THE BOARDING OF CERNAVODA HIGH SCHOOL (29514 LEI).

18 Cernavoda, Iunie 2011 Cernavoda NPP Units 3&4 Project Motivation/Necessity/Opportunity of the Project THE MAIN CHALLENGES FOR THE NATIONAL ENERGY SYSTEM ARE THE INCREASE OF DEMAND, THE REPLACEMENT OF NONPERFORMANT AND OUTDATED CAPACITIES, THE INTEGRATION OF AN INCREASING LARGER QUANTITY OF RENEWABLE ENERGY, THE SECURITY OF SUPPLY AND THE POSITIONING ON THE EUROPEAN REGIONAL MARKET. ROMANIA’S ENERGY STRATEGY FOR THE PERIOD – OBJECTIVES : – ENERGY SAFETY – COMPETITIVENESS ON THE INTERNAL AND REGIONAL MARKET – SUSTAINABLE DEVELOPMENT – ENVIRONMENT PROTECTION AND CLIMATE CHANGE CONTROL – NECESSARY CAPITAL FOR MODERNIZATION AND SECTOR DEVELOPMENT – THE FURHTER DEVELOPMENT OF A COMPETITIONAL MARKET CHARACTERIZED BY COMPETITION, TRANSPARENCY AND LIQUIDITY CERNAVODA NPP UNITS 3&4 REPRESENT A PART OF THE FORESEEN ENERGY MIX AND ENSURE ANNUAL SUPPLEMENTARY ENERGY QUANTITY OF 11 TWH INTO THE NATIONAL ENERGY SYSTEM

19 Cernavoda, Iunie 2011 Cernavoda NPP Units 3&4 Project Project objective Calandria Vassel Pressure tubes Fuelling machine PRODUCTION CAPACITY 2X720 MWE ANNUAL ENERGY OUTPUT 11 TWH CANDU TYPE REACTORS, –NATURAL URANIUM AS FUEL –HEAVY WATER AS MODERATOR AND COOLING AGENT USE OF NATIONAL INFRASTRUCTURE –EXISTING CAPACITIES FOR NUCLEAR FUEL MANUFACTURING AND HEAVY WATER –OPERATION EXPERIENCE OF UNITS 1 & 2 –ENGINEERING KNOWLEDGE OF DESIGN ORGANIZATIONS –ENTREPRENEURIAL EXPERIENCE –AVAILABILITY IN THE MANUFACTURING OF EQUIPMENTS AND MATERIALS –EXPERTISE OF THE REGULATORY BODY –CAPITALIZATION OF SITE AND EXISTING CONSTRUCTIONS

20 Cernavoda, Iunie 2011 Cernavoda NPP Units 3&4 Project Project responsibility S.C. ENERGONUCLEAR S.A. –ESTABLISHED BY GD 1565/2008 AS A JOINT STOCK COMPANY REGISTERED IN ROMANIA IN COMPLIANCE WITH THE LAW OF COMMERCIAL COMPANIES (LAW 31/1990) –HAVING THE OBJECTIVE TO DEVELOP, CONSTRUCT AND OPERATE CERNAVODA NPP UNITS 3&4 ADDITIONAL ACT NR.3 TO THE INVESTORS AGREEMENT – SHAREHOLDING STRUCTURE OF S.C. ENERGONUCLEAR S.A –ARCELORMITTAL GALATI S.A., –ENEL INVESTMENT HOLDING B.V. –S.N. NUCLEARELECTRICA S.A. PROJECT DEVELOPMENT IN 2 PHASES – PRE-PROJECT AND PROJECT PRE-PROJECT PHASE – PREPARATORY ACTIVITIES UP TO INVESTMENT DECISION MAKING –SELECTION OF THE MAIN CONTRACTOR (EPC) –DRAFTING OF NUCLEAR SAFETY AND AUTHORIZATION RELATED DOCUMENTATION –ESTABLISHMENT OF THE ECONOMICAL AND FINANCIAL MODEL, PROJECT FEASIBILITY ASSESSMENT, IDENTIFICATION OF FINANCIAL RESOURCES –CONTRACT DRAFTING FOR THE OPERATION AND MAINTENANCE OF THE GROUPS, HEAVY WATER AND NUCLEAR FUEL SUPPLY THROUGHOUT OPERATION PERIOD. –DRAFTING OF AGREEMENTS FOR ENERGY OFF-TAKE

21 Cernavoda, Iunie 2011 Cernavoda NPP Units 3&4 Project Estimated value THE PROJECT IS ESTIMATED AT 4 BILLION EUROS (ESTIMATIONS DONE IN 2008); WITHIN THE SELECTION PROCEDURE OF THE MAIN CONTRACTOR, THERE ARE SEVERAL PHASES: –QUALIFICATION OF BIDDERS –NEGOTIATION OF PRELIMINARY BIDS –NEGOTIATION OF FINAL OFFERS AND CONTRACT AWARDING THE INVESTMENT COSTS WILL BE DETERMINED BASED ON THE PRELIMINARY OFFERS RECEIVED FORM POTENTIAL CONTRACTORS.

22 Cernavoda, Iunie 2011 Cernavoda NPP Units 3&4 Project Financing resources FINANCIAL CONSULTANT – FINANCING STRUCTURE –INTERNAL RESOURCES AND LOANS OF THE SHAREHOLDERS –“PROJECT FINANCING” LOAN TYPE –SHAREHOLDERS’ GUARANTIES

23 Cernavoda, Iunie 2011 Cernavoda NPP Units 3&4 Project Current status APPROVAL OF THE PROJECT BY THE EUROPEAN COMMISSION; COMPLETION OF EXISTING BUILDING INSPECTION AND CONFIRMATION BY AECL OF THE CONFORMITY WITH THE FUNCTIONS THET THEY WERE INITIALLY DESIGNED FOR. DEFINING OF HIGHER AUTHORIZATION STANDARDS –TARGET VALUES FOR NUCLEAR SAFETY –SIZING OF STRUCTURES AND EQUIPMENTS IN CASE OF EARTHQUAKE PROJECT DEFINITION – IDENTIFICATION AT CONCEPT LEVEL OF PROJECT IMPROVEMENTS AND MODIFICATIONS.

24 Cernavoda, Iunie 2011 CERNAVODA NPP SAFETY READINESS - FUKUSHIMA PERSPECTIVE -

25 Cernavoda, Iunie 2011 FUKUSHIMA DAIICHI UNIT 1 - PRELIMINARY REMARKS  TYPICAL BWR 3 AND 4 REACTOR DESIGN

26 Cernavoda, Iunie 2011

27  AFFECTED BWR UNITS WERE BROUGHT INTO SERVICE IN THE EARLY 1970’s, BEFORE MORE RECENT CHANGES WERE INTRODUCED IN NPP SAFETY REQUIREMENTS;  LIMITED CONTAINMENT VOLUME WHICH ENABLE HYDROGEN TO REACH QUICKLY A RELATIVELY HIGH CONCENTRATION;  A RELATIVELY SMALL RESERVE OF WATER IN AND AROUND REACTOR CORE;

28 Cernavoda, Iunie 2011  INTERIM SPENT FUEL BAY LOCATED MUCH HIGHER THAN GROUND LEVEL;  THE FUKUSHIMA EVENT WAS INITIATED BY AN EARTHQUAKE & TSUNAMI, BOTH BEYOND DESIGN BASIS;  THE EVENT CONSEQUENCES (DAMAGE OF THE NUCLEAR FUEL RESULTED IN RADIOLOGICAL RELEASES) WERE DUE TO A COMBINATION OF A SEVERE COMBINED EXTERNAL EVENT AND THE PARTICULAR CHARACTERISTICS OF THE NUCLEAR PLANT DESIGN.

29 Cernavoda, Iunie 2011 CERNAVODA NPP CANDU 6 SAFETY READINESS OVERVIEW  KEY BACKGROUND POINTS:  CANDU 6 REACTORS HAVE TWO SEPARATE, REDUNDANT FAIL-SAFE SHUTDOWN SYSTEMS, (ONE SEISMICALLY QUALIFIED) WHICH WILL SHUT THE REACTOR DOWN IN ANY SEISMIC EVENT THAT CAUSES OPERATING PARAMETERS TO DEVIATE (SECONDARY CONTROL ROOM SEISMICALLY QUALIFIED);  LARGE VOLUME OF COOLING WATER IS CONTAINED IN THE DOUGING TANK OF THE REACTOR BUILDING (APPROX Mg) READY TO SUPPRES THE PRESURE OR TO COOL BY GRAVITY THE REACTOR CORE;  THE CANDU 6 REACTOR CORE INCLUDES A LARGE VOLUME OF LOW-TEMPERATURE, LOW PRESSURE MODERATOR WATER (APPROX 260Mg) WHICH PROVIDES AN INHERENT BACKUP HEAT SINK. THE LARGE THERMAL CAPACITY OF THIS WATER, AND THE SURROUNDING SHIELDING VAULT WATER (APPROX 600Mg), PROVIDES AN INTERIM HEAT SINK, WITH PASSIVE CAPABILITY FOR MANY HOURS;

30 Cernavoda, Iunie 2011  CANDU 6 UNITS HAVE A LARGE CONTAINMENT BUILDING (IN COMPARISON TO THE FUKUSHIMA UNITS) WHICH LIMITS THE IMPACT OF STEAM DISCHARGE OR HYDROGEN RELEASE INTO CONTAINMENT. OVERALL HYDROGEN CONCENTRATIONS ARE LOW, AND HYDROGEN IS MIXED IN CONTAINMENT BY ACTION OF LOCAL AIR COOLERS AND ALSO BY NATURAL CONVECTION. MITIGATION SYSTEMS (IGNITERS OR RECOMBINERS) ARE DEPLOYED TO MANAGE HYDROGEN FOR CANDU 6;  CERNAVODA NPP CANDU 6 UNITS ARE DESIGNED FOR APPROPRIATE SEISMIC CONDITIONS BASED ON THE CHARACTERISTICS OF CERNAVODA SITE.

31 Cernavoda, Iunie 2011 CONTAINMENT SYSTEM

32 Cernavoda, Iunie 2011 BASIC BLUEPRINT OF CANDU 6 UNIT

33 Cernavoda, Iunie 2011 SHUTDOWN SYSTEMS 1 & 2

34 Cernavoda, Iunie 2011 EMERGENCY CORE COOLING SYSTEM

35 Cernavoda, Iunie 2011 ROBUSTNESS TO DESIGN-BASIS AND BEYOND-DESIGN-BASIS EARTHQUAKES  CERNAVODA NPP CANDU 6 UNITS, LIKE OTHER NUCLEAR PLANTS, ARE DESIGNED TO WITHSTAND EARTHQUAKES BASED ON A “DESIGN BASIS EARTHQUAKE” GROUND MOTION FOR THE CERNAVODA SITE CHARACTERISTICS;  BASED ON APPROVED STUDIES DEVELOPED BY THE ROMANIAN CENTER FOR EARTH PHYSICS THAT TOOK INTO ACCOUNT THE CONSERVATIVE HISTORY OF THE ENTIRE REGION, INCLUDING THE CLOSEST SEISMIC AREAS, VRANCEA AND SHABLA (BALKAN MOUNTAINS), CERNAVODA NPP WAS DESIGNED TO RESIST EFFECTS OF EARTHQUAKES. THE ABOVE-MENTIONED STUDIES HAVE SHOWN THAT, HISTORICALLY, THE TWO OUTBREAKS LOCATED AT OVER 100KM FROM SITE NEVER HELD AN EARTHQUAKE GREATER THAN 7.5 DEGREES. IN THIS CONTEXT, CERNAVODA NPP PROJECT CONSERVATIVELY CONSIDERED A MAXIMUM POSSIBLE EARTHQUAKE OF MORE THAN 8 DEGREES;  THE INITIAL PROJECT, WHICH CONSIDERED A DESIGN BASIS EARTHQUAKE THAT MIGHT OCCUR EVERY MORE THAN 1000 YEARS AND MIGHT PRODUCE A MAXIMUM PEAK ACCELERATION OF 0.2G AT GROUND LEVEL, WAS CONFIRMED BY SUBSEQUENT STUDIES AUDITED BY IAEA EXPERTS.  THESE STUDIES HAVE EXAMINED IN DETAIL THE PLANT RESPONSE CONCLUDING THAT THERE ARE SIGNIFICANT DESIGN MARGINS (>0.35G) FOR SEISMIC EVENTS BEYOND THE DESIGN BASIS, AN EARTHQUAKE THAT MIGHT OCCUR EVERY YEARS.

36 Cernavoda, Iunie 2011 SEISMIC CAPACITY AFTER SEISMIC FRAGILITY ANALYSIS FOR THE NUCLEAR BUILDINGS AND GENERATORS NO.SUBJECTMAXIMUM GROUND ACCELERATION DESIGN GROUND ACCELERATION RECCURENCE PERIOD (YEARS) 1R/B – internal structures0.45g0.204g>1/ R/B – containment wall0.45g0.204g>1/ S/B - block walls0.35g0.204g>1/ T/B0.30g0.204g>1/ D2O-Tower, EPS/SCR, HPECC, EWS >0.45g0.204g>1/ Pump House0.30g0.204g>1/ StandBy Diesels0.45g0.204>1/ Generators3.20g0.204g>1/10000 Nota: PGA value for a recurrence period of 1/10000 years is 0.291g according to preliminary results Rizzo & Associates studies. PGA value for current DBE (period of 1/1000 years) is 0.204g.

37 Cernavoda, Iunie 2011 BEYOND DESIGN-BASIS FLOODING  CERNAVODA NPP CANDU 6 PLANT IS ASSESSED FOR ITS CAPABILITY TO WITHSTAND BOTH INTERNALLY-CAUSED (e.g. PIPING RUPTURE) OR EXTERNALLY- CAUSED FLOODS;  ANY EXTERNALLY-CAUSED FLOOD WOULD NOT AFFECT THE SYSTEMS AND STRUCTURES INSIDE THE CONTAINMENT, WHICH IS DESIGNED TO BE SEALED OFF FROM THE OUTSIDE;  THE REALITY SHOWS THAT CERNAVODA NPP SITE IS LOCATED AT 15.8M ABOVE THE BLACK SEA LEVEL AND 2M ABOVE THE MAXIMUM POSSIBLE LEVEL OF DANUBE WATERS, WHICH MAY OCCUR IN 10,000 YEARS;  THE DRAINAGE SYSTEMS OF CERNAVODA NPP SITE CAN ACCOMMODATE MORE THAN 100l/ h/ m 2 AND IS SURROUNDED BY A WATER COLLECTION NETWORK DESIGNED TO WITHSTAND A SEVERE QUICK RAINFALL. IN ROMANIA, THE MORE SEVERE QUICK RAINFALL THAT CAUSED EXTREME FLOODS HAS NEVER EXCEEDED 75l/ h/ m2.

38 Cernavoda, Iunie 2011 RESPONSE TO PROLONGED STATION BLACKOUT  AFTER THE REACTOR IS SHUTDOWN, BY DESIGN, CERNAVODA NPP CANDU 6 HAS A NUMBER OF SYSTEMS TO REMOVE DECAY HEAT, SUCH AS THE FEEDWATER SYSTEM, SHUTDOWN COOLING SYSTEM, MODERATOR SYSTEM AND EMERGENCY WATER SUPPLY;  FEEDWATER SHUTDOWN COOLING AND MODERATOR SYSTEMS OPERATE UNDER CLASS IV AND CLASS III POWER (INDEPENDENT DIESEL GENERATORS);  IF CLASS IV AND CLASS III POWER ARE UNAVAILABLE, SEISMICALLY QUALIFIED EPS WILL BE STARTED. IN THIS CASE, PUMPED EMERGENCY WATER SUPPLY (EWS) OPERATING UNDER EPS CAN ENSURE LONG TERM FUEL COOLING;  FOLLOWING TOTAL LOSS OF OFF-SITE AND ON-SITE POWER, THE STEAM GENERATOR HEAT SINK IS MAINTAINED BY MAKE-UP TO STEAM GENERATORS BY GRAVITY FROM THE DOUDING TANK, AFTER STEAM GENERATOR RAPID COOLDOWN.

39 Cernavoda, Iunie 2011 ABILITY TO RESTORE AND MAINTAIN LONG TERM COOLING TO CORE  AS NOTED ABOVE, EVEN IN THE ABSENCE OF ALL ELECTRICAL POWER, NATURAL CIRCULATION FLOW IN THE HEAT TRANSPORT SYSTEM COUPLED WITH PASSIVE GRAVITY- FED SUPPLY OF WATER TO THE STEAM GENERATORS, PROVIDES COOLING FOR SEVERAL DAYS;  IN THE LONGER TERM, ARRANGEMENTS CAN BE MADE TO REPLENISH WATER IN THE DOUSING TANK VIA EITHER THE FIREWATER SYSTEM OR WATER TANKER TRUCKS;  BY DESIGN, THE CANDU 6 CORE IS SUBDIVIDED INTO FUEL CHANNELS, EACH SURROUNDED BY LOW-PRESSURE, LOW-TEMPERATURE MODERATOR HEAVY WATER. THIS MEANS THAT, OVERALL THERE IS A RELATIVELY LARGE AMOUNT OF WATER AVAILABLE FOR EMERGENCY FUEL COOLING;

40 Cernavoda, Iunie 2011 ABILITY TO RESTORE AND MAINTAIN LONG TERM COOLING TO CORE (CON’T)  THE LARGE QUANTITIES OF WATER IN THE MODERATOR AND SHIELD TANK MEAN THAT, EVEN IN THE PROLONGED ABSENCE OF ELECTRIC POWER, AND ASSUMING THE FAILURE OF NATURAL CIRCULATION COOLING, MANY HOURS OF TIME WOULD ELAPSE BEFORE THE WATER NEEDS TO BE REPLENISHED;  IN ADDITION, TWO VERY IMPORTANT FEATURES HAVE BEEN PROVIDED:  TWO WATER WELLS HAVE BEEN DRILLED FOR PROVIDING COOLING WATER, WITH A CAPACITY OF 190m³/h;  TWO MOBILE DIESEL GENERATORS HAVE BEEN BROUGHT ON SITE AS OUTSIDE ALTERNATIVE ELECTRICAL SOURCE FOR EWS & SCR.

41 Cernavoda, Iunie 2011 ROBUSTNESS OF SPENT FUEL MANAGEMENT SYSTEMS  THE RISK OF FUEL UNCOVERING AND OVERHEATING IN CANDU 6 SPENT FUEL BAYS (SFB) IS EXTREMELY LOW DUE TO THE REDUNDANT POWER SUPPLY OPTIONS, THE MODEST FUEL HEAT LOAD, AND THE LARGE INVENTORY OF WATER WHICH ENSURES A LONG PERIOD OF TIME AVAILABLE TO RESTORE COOLING;  THE SFBs ARE REINFORCED CONCRETE VESSELS LOCATED BELOW GRADE LEVEL. THE BAYS ARE DESIGNED TO WITHSTAND A DESIGN BASIS EARTHQUAKE (DBE);  ASSESSMENTS HAVE SHOWN THAT THERE IS SUFFICIENT SEISMIC MARGIN IN THE SFB DESIGN TO SURVIVE AN EARTHQUAKE GREATER THAN THE DBE WITHOUT THE WALL RUPTURING;  THE PIPING LAYOUT FOR THE BAY COOLING SYSTEM IS DESIGNED TO PROHIBIT DRAINING OF THE BAY IN THE EVENT OF A PIPE RUPTURE;  DECAY HEAT FROM THE SPENT FUEL IN THE SFB IS REMOVED BY RE- CIRCULATING THE BAY WATER THROUGH A HEAT EXCHANGER, WITH PUMPS POWERED BY OFF-SITE CLASS IV AND BACKUP CLASS III POWER;

42 Cernavoda, Iunie 2011 ROBUSTNESS OF SPENT FUEL MANAGEMENT SYSTEMS (CON’T)  CERNAVODA NPP CANDU 6 NATURAL URANIUM FUEL BUNDLES ARE GRADUALLY DISCHARGED DURING REACTOR OPERATION AND ARE STORED IN THE BAY FOR ABOUT 6 YEARS BEFORE THEY CAN BE MOVED TO PASSIVE AIR-COOLED DRY STORAGE (WHICH DOES NOT NEED ANY EXTERNAL SOURCE OF POWER OR OTHER SERVICES);  ALTERNATIVE METHODS TO COOL THE SPENT FUEL BAY ARE AVAILABLE FROM FIREWATER OR AN EXTERNAL SOURCE (WELL WATER & FIRE TRUCK);  EVEN IN THE CASE IN WHICH THE MAXIMUM FUEL LOAD IS IN THE BAY AND THE COOLING CIRCUIT IS NOT AVAILABLE DUE TO LOSS OF ALL AVAILABLE POWER SUPPLIES, IT WOULD TAKE APPROXIMATELY 13 DAYS BEFORE THE TOP ROW OF THE FUEL BUNDLES BECOME UNCOVERED, AND EVEN LONGER BEFORE ANY SIGNIFICANT FUEL OVERHEATING OCCURS;

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