Smahtrforinfocastsymposium28mar11

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Presentation for the Infocast Advanced SMR Sumposium, March 2011

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Smahtrforinfocastsymposium28mar11

  1. 1. SmAHTR – the SmallModular Advanced HighTemperature ReactorPresented toInfocast SMR SymposiumWashington, DCMarch 28, 2011BySherrell GreeneDirector, Research Reactors Development ProgramsOak Ridge National Laboratorygreenesr@ornl.gov, 865.574.0626
  2. 2. Presentation overview* •  Fluoride salt •  Fluoride salt-cooled high temperature reactors (FHRs) •  SmAHTR FHR design objectives •  Preliminary SmAHTR concept •  SmAHTR concept optimization and design trades •  Principal SmAHTR development challenges * S. R. Greene, J. C. Gehin, D. E. Holcomb, et al., Pre-Conceptual Design of a Fluoride-Salt-Cooled Small Modular Advanced high-Temperature Reactor (SmAHTR), ORNL/TM-2010/199, Oak Ridge National Laboratory, December 20102 Managed by UT-Battelle for the U.S. Department of Energy S. R. Greene, 28 Mar 11
  3. 3. What the heck is “fluoride salt” ? Liquid and “Frozen” 2LiF-BeF2 salt •  “Fluoride salt” is a “halide salt” •  Halide salts are ionic compounds formed from the combination of a halogen and another element – commonly, but not exclusively, alkali metals or alkaline earths •  Examples: LiF, BeF2, KF, NaF, ZrF4, RbF, and3 Managed by UT-Battelle mixtures of same for the U.S. Department of Energy S. R. Greene, 28 Mar 11
  4. 4. Fluoride salt-cooled High Temperature Reactors (FHRs) combine the best attributes of other reactor types to provide unique performance benefits Molten Salt Liquid Metal Reactors Reactors •  Halide salt coolant •  Low pressure •  Metallic materials •  Integral primary •  Heat exchangers system •  Passive decay Gas Cooled Light Water heat removal Reactors Reactors •  TRISO fuel •  Water / Air- •  Graphite tolerant coolants •  Brayton Power •  Excellent coolant Conversion heat transport Fluoride Salt Reactors •  Very high temperature •  Low pressure •  Compact system •  Excellent heat transport4 Managed by UT-Battelle for the U.S. Department of Energy S. R. Greene, 28 Mar 11
  5. 5. FHRs incorporate many attractive attributes for high-temperature applications Coolant   High   Low   (Reactor   High  Working   Volumetric   Low  Primary   Reac>vity   Concept)   Tempa   Heat   Pressurec   With  Air  &   Capacityb   Waterd   Water  (PWR)   "    "    Sodium  (SFR)            " Helium  (GCR)      " "    Salt  (AHTR)               a FHR system working temperature functionally limited by structural materials capabilities b High coolant volumetric heat capacity enables ~constant temperature heat addition / removal (η = 1 C – TC/TH ~ Carnot cycles), compact system architectures, and reduces pumping power requirements c Low primary system pressure reduces cost of primary vessel and piping, and reduces energetics of pipe break accidents d Low reactivity with air and water reduces energetics of pipe break accidents5 Managed by UT-Battelle for the U.S. Department of Energy S. R. Greene, 28 Mar 11
  6. 6. FHRs are promising candidates for traditional and non-traditional applications •  Electricity production –  Large centralized –  Small remote site •  High and Very High-Temperature Process Heat production –  Large centralized –  Small remote site •  Incremental energy demand growth scenarios •  Compact power applications6 Managed by UT-Battelle for the U.S. Department of Energy S. R. Greene, 28 Mar 11
  7. 7. FHRs coupled with Brayton power conversion systems can be highly efficient electricity generators FHRs LWRs7 Managed by UT-Battelle for the U.S. Department of Energy S. R. Greene, 28 Mar 11
  8. 8. Potential FHR operating temperatures match many important process heat applications LiF-BeF2 (67-33) nge re Ra LiF-NaF-KF (46.5-11.5-42) Tem peratu iquid ide Salt L NaF-BeF2 (57-43) Fluor Melts Boils H2 Production & Coal Gasification Steam Reforming of Nat. Gas & Biomass Gasification Cogeneration of Electricity and Steam Oil Shale/Sand Processing Petro Refining 0 100 200 300 400 500 600 700 800 900 1000 110 1200 1300 1400 1500 1600 1700 Temperature (C)8 Managed by UT-Battelle for the U.S. Department of Energy S. R. Greene, 28 Mar 11
  9. 9. SmAHTR and AHTR are products of ORNL’s investigation of the Fluoride salt-cooled High-temperature Reactor (FHR) design space •  Reactor power level AHTR •  Physical size •  System complexity 125 MWt •  Operating temperature •  Fuel and core geometry •  Materials 3400 MWt •  Economics •  Applications9 Managed by UT-Battelle for the U.S. Department of Energy S. R. Greene, 28 Mar 11
  10. 10. SmAHTR design objectives target both electricity and process heat production •  Initial concept operating temperature of 700 ºC with future evolution path to 850 ºC and 1000 ºC •  Thermal size matched to early process heat markets •  Integral, compact system architectures •  Passive decay heat removal •  Truck transportable •  Multi-reactor systems with integral thermal energy storage10 Managed by UT-Battelle for the U.S. Department of Energy S. R. Greene, 28 Mar 11
  11. 11. SmAHTR is an “entry-level” very- high-temperature reactor (VHTR) Overall System Parameters Parameter   Value   Power  (MWt  /  MWe)   125  /  50+   Primary  Coolant   LiF-­‐BeF2   Primary  Pressure  (atm)   ~1   Core  Inlet  Temperature  (ºC)   650   Core  Outlet  Temperature  (ºC)   700   Core  coolant  flow  rate  (kg/s)   1325   OperaQonal  Heat  Removal   3  –  50%  loops   Passive  Decay  Heat  Removal   3  –  50%  loops   Power  Conversion   Brayton   Reactor  Vessel  PenetraQons   None  11 Managed by UT-Battelle for the U.S. Department of Energy S. R. Greene, 28 Mar 11
  12. 12. SmAHTR is small… B&W mPower (400 MWt / 125 MWe) NuScale (160 MWt / 45 MWe) SmAHTR 23 m (125 MWt / 50 MWe) 18.3 m 9m 3.6 m 4.3 m 4.5 m12 Managed by UT-Battelle for the U.S. Department of Energy S. R. Greene, 28 Mar 11
  13. 13. SmAHTR is a cartridge-core, integral-primary-system FHR (1 of 3) (1 of 3) Downcomer Skirt13 Managed by UT-Battelle for the U.S. Department of Energy S. R. Greene, 28 Mar 11
  14. 14. SmAHTR primary system mechanical design enables rapid component servicing and refueling IHX removal DRACS Core Removal Reflector removal Removal14 Managed by UT-Battelle for the U.S. Department of Energy Note: downcomer skirt not shown S. R. Greene, 28 Mar 11
  15. 15. Cylindrical annular compacts are current SmAHTR reference fuel concept Op>on  2   SmAHTR  Fuel  /  Core  Parameter   Op>on  1   (Reference)   Op>on  3   Solid  Cylindrical   Annular  Cylindrical   Compact  Stringers   Compact  Stringers   Flat  Fuel  Plates  in   Fuel  Assembly  Design   in  Hex  Graphite   In  Hex  Graphite   Hex  ConfiguraQon   Blocks   Blocks   UCO  fuel  kernel  diameter  (microns)   425   500   500   Number  fuel  columns  or  assemblies   19   19   19   Number  fuel  pins  /  plates  per  column   72   15   9   or  fuel  element   Number  graphite  pins    or  plates  per     19   4   9   column  or  fuel  element   IniQal  Fissile  Mass  (kg)   195   357   398   Total  Heavy  Metal  (kg)   987   1806   2015   Enrichment   19.75%   19.75%   19.75%   Avg.  Power  Density  (MW/m3)   9.4     9.4   9.4   Refueling  Interval  (yr)   2.5     4.0   3.1  15 Managed by UT-Battelle for the U.S. Department of Energy S. R. Greene, 28 Mar 11
  16. 16. Three identical in-vessel primary heat exchangers remove operational heat Intermediate Heat Transport Loop Parameters Parameter   Value   Number  of  Primary  Heat  Exchangers  (PHX)   3   Number  PHX  needed  for  full  power  opera>on   2   PHX PHX  Design  Concept   Single-­‐pass,  tube-­‐in-­‐shell   Primary  Coolant   LiF-­‐BeF2   Primary  Inlet  Temperature  (ºC)   700   Primary  Outlet  Temperature  (ºC)   650   Primary  flow  rate  (kg/s)   350  (x  3)   Secondary  Coolant   LiF-­‐NaF-­‐KF   Secondary  Inlet  Temperature  (ºC)   600   Secondary  Outlet  Temperature  (ºC)   690   Secondary  flow  rate  (kg/s)   247  (x3  )  16 Managed by UT-Battelle for the U.S. Department of Energy S. R. Greene, 28 Mar 11
  17. 17. Three identical in-vessel heat exchangers remove post-scram decay heat In-vessel Passive Decay Heat Removal System Parameters In-­‐vessel  DRACS  HX  Parameter   Value   PHX Number  DRACS  in-­‐vessel  heat  exchangers   3   Number  DRACS  loops  needed  for  full   2   power  opera>on   DRACS  Salt-­‐to-­‐Salt  Design  Concept   Single-­‐pass,  tube-­‐in-­‐shell   Primary  Coolant   LiF-­‐BeF2   Secondary  Coolant   LiF-­‐NaF-­‐KF  17 Managed by UT-Battelle for the U.S. Department of Energy S. R. Greene, 28 Mar 11
  18. 18. SmAHTR DRACS utilizes salt-to-air, natural convection heat rejection Ex-vessel Passive Decay Heat Removal System Parameters Ex-­‐vessel  DRACS  HX  Parameter   Value   Salt-to- FLiNaK Air Number  DRACS   3   Radiator Number  DRACS  needed  for  full  power   2   opera>ons   DRACS  Salt-­‐to-­‐Air  Design  Concept   Ver>cal  finned  tube  radiator   Primary  Coolant   LiF-­‐NaF-­‐KF   Air Air  Flow  Area  (m2)   4   In- vessel In-­‐vessel  HX  –  to  –  air  HX  riser  height  (m)   8   DRACS FLiBe HX Total  chimney  height  (m)   12   ~18 Managed by UT-Battelle for the U.S. Department of Energy S. R. Greene, 28 Mar 11
  19. 19. SmAHTR is good match with Brayton power conversion technologies •  Options –  Standard closed –  Supercritical closed –  Open air (similar to ANP & HTRE) •  Issues to consider –  Physical size & weight –  Multi-unit clustering –  Heat exchanger pressure differentials –  Efficiency and scalability to higher temperatures –  Tritium leakage –  Compatibility with dry heat rejection •  Trade study underway19 Managed by UT-Battelle for the U.S. Department of Energy S. R. Greene, 28 Mar 11
  20. 20. SmAHTR thermal energy storage “salt vault” enables clustering of multiple reactors •  Liquid salt vault acts as thermal battery •  Salt vault buffers –  reactors from load –  reactors from each other •  Salt selection and salt vault size can be optimized for differing applications –  125 MWt-hr storage @ 500 –600 ºC requires ~ 13 meter cubic salt tank20 Managed by UT-Battelle for the U.S. Department of Energy S. R. Greene, 28 Mar 11
  21. 21. Preliminary transient analysis confirmsrobust SmAHTR design 1178°C Transient: All cooling pumps trip, 20 s coast-down, 10 s delayed scram ~1230°C 650°C 700°C •  Peak fuel temperatures during normal operations are acceptable •  Peak transient fuel temperatures for loss-of-flow with delayed scram are acceptable •  Smooth transition to natural circulation decay heat removal21 Managed by UT-Battelle for the U.S. Department of Energy S. R. Greene, 28 Mar 11
  22. 22. Materials R&D will pace evolution to higher operating temperatures System Element @ 700 ºC @ 850 ºC @ 1000 ºCGraphite Internals Toyo Tanso IG110 or 430 Toyo Tanso IG110 or 430 Toyo Tanso IG110 or 430Reactor Vessel Hastelloy-N • Ni-weld overlay on 800H • Interior-insulated low- • Insulated low-alloy steel alloy steel • New Ni-based alloyCore barrel & Hastelloy-N • C-C composite • C-C compositeother internals • New Ni-based alloy • SiC-SiC composite • New refractory metalControl rods and • C-C composites • C-C composites • C-C compositesinternal drives • Hastelloy-N • Nb-1Zr • Nb-1Zr • Nb-1ZrPHX & DRACS Hastelloy-N • New Ni-based alloy • C-C composite • Double-sided Ni cladding • SiC-SiC composite on 617 or 230 • Monolithic SiCSecondary (salt- Coaxial extruded 800H • New Ni-based alloy ?to-gas) HX tubes with Ni-based • Coaxial extruded 800H22 Managed by UT-Battelle layer tubes with Ni-based layer for the U.S. Department of Energy S. R. Greene, 28 Mar 11
  23. 23. An integrated S&T strategy is neededto deliver on FHR promise •  Fuels: –  Continue and optimize on-going TRISO fuels S&T •  Materials: –  High-nickel alloys, graphite, C-C composites, and SiC –  Optimized salts •  Components –  Heat exchangers –  Pumps –  Valves –  Instrumentation •  Open and closed Brayton Cycle power conversion23 Managed by UT-Battelle for the U.S. Department of Energy S. R. Greene, 28 Mar 11
  24. 24. Summary •  FHRs are a new class of reactor that leverages best features of traditional reactors •  SmAHTR is a small, “entry-level” VHTR concept –  explores the small modular FHR design space •  SmAHTR design objectives target : –  process heat production and electricity generation –  ease of transport and deployment –  long-term evolvability to higher efficiency electric generation and higher temperature process heat applications •  Present concept demonstrates feasibility and promise •  Present concept is not optimized –  Fuel / core geometry (fixed, pebble-bed, etc.) –  Power density –  Mechanical design –  Salt vault24 –  Conduct of operations Managed by UT-Battelle for the U.S. Department of Energy S. R. Greene, 28 Mar 11
  25. 25. Backup25 Managed by UT-Battelle for the U.S. Department of Energy S. R. Greene, 28 Mar 11
  26. 26. The potential benefits and challenges of FHRs stem from fundamental materials characteristics High  coolant   High  coolant   volumetric   melQng   heat  capacity   temperature  26 Managed by UT-Battelle for the U.S. Department of Energy S. R. Greene, 28 Mar 11
  27. 27. FHR salt coolant heat transfertechnologies were successfullydemonstrated in MSRE for > 26,000 hr Molten Salt Reactor Experiment (1965 – 1969)MSRE LiF-BeF2 Secondary Coolant Loop 600 ˚C LiF-BeF2 / Air Blast Radiator27 Managed by UT-Battelle for the U.S. Department of Energy S. R. Greene, 28 Mar 11
  28. 28. Four fuel assembly concepts are underconsideration (3 fixed core and pebble-bed) Solid cylindrical compact stringers Annular cylindrical compact stringers Hex-plate fuel assemblies Pebble Bed •  Cylindrical fuel assembly O.D. = 34 cm •  Plate fuel assembly O.D. = 43 cm28 Managed by UT-Battelle for the U.S. Department of Energy S. R. Greene, 28 Mar 11
  29. 29. SmAHTR employs a two-out-of-three approach for operational and decay heat removal29 Managed by UT-Battelle for the U.S. Department of Energy S. R. Greene, 28 Mar 11

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