SIMULATION – key for Safe Energy Production

1. SIMULATION – key forSafe Energy Production Janos Sebestyen JANOSY Senior Consultant Technical and Scientific Support Organization Janos.S.Janosy@energia.mta.hu

2. Industrial Revolution = EnergyEnergy = Steam engine = 90% even now! Engines: we got time to brainwork Belt transmission Power control: Speed control! EMS2012, Malta, 14 – 16 November

3. Factories

4. Our perspective is not very bright Environmental problems: Environmental problems – pollution, climate change, exhaustion of the resources, etc. – some kind of “overspending” Economic problems: Financial crisis, too much credits – all the same - overspending! Something has to be changed – it’s going to change anyway … EMS2012, Malta, 14 – 16 November

5. Contents – three questions - Do we really need so much energy – can we do with less? - Why not to switch to alternatives immediately – why we need fossils and nuclear power? - What is the problem with nuclear energy? Why accidents happen? - Conclusions EMS2012, Malta, 14 – 16 November

6. Hungary – less then middle developed in EU • - Average electrical power per person – 425 W • - Average family in Hungary – 4 persons, 1700 W • - A man’s capacity is less than 100 W in 8 hours • The 1700 W = 17 “slaves” in 3 shifts = 51 people(without logistics) • An average Hungarian family has 51 workers just from electricity consumption of his country! • Gas for cars, natural gas heating etc. etc. Energy – key to technical development I. EMS2012, Malta, 14 – 16 November

7. U.S.A., after WWII: Interstate Highway Program. Roads, cars, housing in suburbs. Lot of work! Energy – key to technical development II. Results: Middle class lifestyle: Work: ~60km Shop: ~20km Theatre: ~120km EMS2012, Malta, 14 – 16 November

8. Population in 1949: less than 2 billionsPopulation in 2012: reached 7 billions Energy was abundant and cheap to the developed countries – the style and development directions they took is not affordable to anybody on the earth … … At least not as things are nowadays … even less with the present economic crisis! Energy – key to technical development III. EMS2012, Malta, 14 – 16 November

9. Energy – key to technical development IV. Exponential growth – induced exponential growth in energy (slower exp.) and food production (higher exp.) ! And everybody used to grow the same way. No big leap forward. Not sustainable too much longer … That is probably a wrong direction … We do not see dramatic changes so far – that we are going to turn into any other (sustainable) direction! EMS2012, Malta, 14 – 16 November

10. Energy Production, Consumption & Efficiency Sources: International Energy Agency Statistics, World Population Prospects Database - 2008 EMS2012, Malta, 14 – 16 November

11. Status of CO2 - as it is now ... Equilibrium in chemical processes Burning (heat generated) → Conc.: .028% C+O2 ↔ CO2 Conc.:20% ← Photosynthesis (energy absorption) All carbon is "hidden" below earth surface ... Efficiency of the photosynthesis: lessthan 1% It is NOT an equilibrium - drifted fully to the left ... It could be the opposite side, too ... ?!? EMS2012, Malta, 14 – 16 November

12. The CO2 problem I. • - Before Industry – 280 ppm (photosynthesis?) • - Late 1950s – 315 ppm, 113 % • - In 2008 – 380 ppm, 136 % • - Growing by exponent … now 2 ppm/year • Threshold value – around 450 ppm, 161 % • The expected growth is far higher than the growth of the global industry, because: • Big developing countries: China, India – per capita producing far less than the U.S.A., but are growing more rapidly and have big populations EMS2012, Malta, 14 – 16 November

13. The CO2 problem II. • U.S.A. producing around a quarter of all CO2 • and keep growing 20% between 2000-2020 • China: • produces 80% of the cement & concrete of the whole world (lot of energy needed for that) • Coal-firing new power plants are connected to grid every week or so (lot of new carbon release) • China, India: Nuclear power cannot catch-up to the speed of the growth even if they would like … EMS2012, Malta, 14 – 16 November

14. Contents – three questions - Do we really need so much energy – can we do with less? - Why not to switch to alternatives immediately – why we need fossils and nuclear power? - What is the problem with nuclear energy? Why accidents happen? - Conclusions EMS2012, Malta, 14 – 16 November

15. Renewables, alternatives I. Renewables: directly and indirectly: all produced by the SUN Directly: Not producing CO2 - Solar panel (not feasable yet), solar boiler - Wind mill, wind turbine - Water dams, water turbines - Wave power (?), on coastlines EMS2012, Malta, 14 – 16 November

16. Renewables, alternatives II. Renewables: directly and indirectly: all power produced by the SUN Indirectly: Not producing CO2 , too! - Biomass - Bio-ethanol, bio-diesel EMS2012, Malta, 14 – 16 November

17. Renewables, alternatives III. Alternatives: Not producing CO2 - either - Fusion power (as ITER) – still far ahead - Geothermal energy – questionable (because not renewable!) - Electrical cars: at least questionable … EMS2012, Malta, 14 – 16 November

18. Ethanol : Octane is 113 (better than gas) - but energy content: abt. 67% of the gas Diesel: about the same as diesel from crude oil (Ford originally used ethanol, andDieseloil from peanuts!) These are questionable numbers: More energy - let's use the sun ?! EMS2012, Malta, 14 – 16 November

19. Terrain = const. Food production problems I. Terrain = Wildlife habitats, national parks ORAgriculture,that means- Food production - OR Bio-energy production EMS2012, Malta, 14 – 16 November

20. Food production problems II. - Population is growing exponentially- Food production has to grow (at least) exponentially, too …- It could be done only by intensification (fertilizers, pesticides, machinery, etc.) resulting in much bigger yields- Soils not cultivated intensively are already limited. Cutting rain forests even more?! - “Bio” production: clearly a concurrent EMS2012, Malta, 14 – 16 November

21. Food prod.prob-lems III.Sara-wak EMS2012, Malta, 14 – 16 November

22. Food production problems III. - Changing habits: we eat more meat … - Hungary: even in the XIX. century: commons were eating meat only once, max. twice a week; now every day; - China: changing the same way: - Developed countries: 20-25% of meat - China: now 3-5% but growing fast - Eating meat means: 6 times more vegetation should be produced!! EMS2012, Malta, 14 – 16 November

23. Problems with the renewables • Basically most of them are unpredictable, except water power (melting snow, storage) • Electrical energy cannot be stored, production should be equal to consumption (water plants can mitigate the storage problem a little) • Without significant amount of water dams unpredictable part should be less than 12-14% • With significant amount of water power it can be up to max. 20-24% of power • In Hungary: nuclear power 40%, in France: ~70% • Anyway, we have to have backup – costs! EMS2012, Malta, 14 – 16 November

24. Contents – three questions - Do we really need so much energy – can we do with less? - Why not to switch to alternatives immediately – why we need fossils and nuclear power? - What is the problem with nuclear energy? Why accidents happen? - Conclusions EMS2012, Malta, 14 – 16 November

25. Basic problems of NPPs I. • Three significant incidents so far: • Three Mile Island accident: poor instrumentation, insufficient information, wrong operating philosophy • Chernobyl: known but unhandled design flaw, clear violation of the operational rules • Fukushima: Inadequate preparation to natural disaster, outdated old plant EMS2012, Malta, 14 – 16 November

26. Basic problems of NPPs II. • "Remnant" heat is generated for long even after the chain reaction is switched off ... • Fuel rods of Ø9-Ø10 mm diameter, 2.5-4.5 m long, Zirconium cladding, inside U2O5 pellets, power density 70-90 kW/Liter (!) - even after shutdown several kW/Liter - if the fuel rods are not covered by water, they melt down (electrical teapot effect) • Practically THE SAFETY means: keep the core under water and cooled ALL THE TIME! EMS2012, Malta, 14 – 16 November

27. Basic problems of NPPs III. • Fission means splitting U235 atoms by chain reaction, using neutrons. 93-94% of heat comes from fission. • All the fission products – parts of the former U235 atom –can be found in the periodical table, they are all well known elements – like iodine, iron, lead, etc. • Parts of these element have excess energy, they are radioactive, they get rid of this energy by radiation and producing heat. • This heat gives the 6-7% of energy, not coming directly from chain reaction, from fission itself. This heat cannot be eliminated, it produced by radioactive decay. EMS2012, Malta, 14 – 16 November

28. % Heat after shutdown I. Time after shutdown, hours EMS2012, Malta, 14 – 16 November

29. % Heat after shutdown II. Time after shutdown, seconds EMS2012, Malta, 14 – 16 November

30. The 6-loop VVER-440 EMS2012, Malta, 14 – 16 November

31. The FUKUSHIMA boiling water reactor unit I. EMS2012, Malta, 14 – 16 November

32. The FUKUSHIMA boiling water reactor unit I. EMS2012, Malta, 14 – 16 November

33. NPP design concepts • 1. NO (normal operation) • 2. AOO (anticipated operational occurrences) Turbine and pump trips, valve malfunctions, equipment failure etc. etc. • These should be handled without further damage to the equipment. No release should happen. • 3. DBA (design basis accident) e.g. LOCA, big cooling pipe break. The core should not melt – the proper cooling should be provided even in this case. • 4. BDBA (Beyond design basis accident) – everything unthinkable. The core can melt, but significant amount of radioactivity should not be released. EMS2012, Malta, 14 – 16 November

34. What happened? • Plant withstood the Magnitude 9 Earthquake – all units tripped normally. The roads were destroyed, electrical power lines crushed, external power out, the units all stopped: internal power out as well. The diesel generators started normally. The cooling went on normally. • After several hours later the tsunami arrived. The plant was designed to withstand 8m tsunami, but it was 11m high. It destroyed the infrastructure, including the cooling radiators of the diesels, and the fuel tanks. They stopped and the cooling of the fuel rods ceased. • Being higher on the slope, the 5th and 6th unit withstood the tsunami, too, they are in good shape, they were restarted already. EMS2012, Malta, 14 – 16 November

35. What happened after that? • There was no cooling, no energy. The cores started to dry out and heat up. Even if it goes to melting, it is foreseen what would happen. The vessel is cooled, still sitting in water, if it fails and melts through, there is the core catcher etc. The 3 layers of the containment will keep the decaying fission products inside. This process evolves for weeks, there is time recover the cooling somehow. • Then the Zirconium reaction came, what was not regarded as of basic importance 40 years ago. • (The cladding of the fuel element is made of Zirconium.) EMS2012, Malta, 14 – 16 November

36. The disastrous Zr reaction • Here is it: • Zr + 2 H2O  ZrO2 + 2H2 + 5 MJ/kg-Zr • To start the reaction we need 1200C. We get it if there is no cooling in the core. • The zirconium is burning, reducting the oxygen from water. That needs energy, but the remaining 5MJ energy is a lot for 1kg of Zirconium. • An there is the produced hydrogen … EMS2012, Malta, 14 – 16 November

37. Contents – three questions - Do we really need so much energy – can we do with less? - Why not to switch to alternatives immediately – why we need fossils and nuclear power? - What is the problem with nuclear energy? Why accidents happen? - Conclusions EMS2012, Malta, 14 – 16 November

38. The consequences • Shock tests to be performed to NPPs all over • If there are no energy reasonable replacements, we should do everything according to our best knowledge • USA: new units are to be constructed in Texas, tax shelter for the first 6 new units • Russia, Mexico, France, Finland, China are started construction of new plants - over 30 reactors are already under construction – Japan, Sweden are considering • Japan: stopped 53 of 54, very bad economic difficulties • Germany and some others (?) are gradually stopping EMS2012, Malta, 14 – 16 November

39. What should be done? • Generation IV: Inherent safety! • Cooling should be maintained with natural circulation, without external energy or human interaction. • Properly cooled: no Zr reaction, but enough Hydrogen re-combiners should be installed • On the design desks already long before Fukushima happened. EMS2012, Malta, 14 – 16 November

40. Upper water tank: starts cooling if temperature is high enough Natural circulation: - Air cooling - Internal cooling Reactor vessel is the lowest point, all the water flows there No external energy and no human/automatic interaction is needed An example: EMS2012, Malta, 14 – 16 November

41. The tank condenses the blow down, feeds the reactor vessel; water is collected from the floor and led to the core without external energy or interaction Core cooling: EMS2012, Malta, 14 – 16 November

42. All or existing knowledge is concentrated now in simulation packages, simulation codes; The codes/packages are verified and validated carefully against well-designed experiments, recorded transients and accidents; We are asking the questions and simulation gives us answers; The key point is: are we asking all the right questions? May be we forget to ask sometimes something extraordinary? Simulation: everywhere, everything, always EMS2012, Malta, 14 – 16 November

43. Thank you for your attention!Questions? EMS2012, Malta, 14 – 16 November