Extrapolation of GDT Results to a DT Fusion Neutron Source for Fusion Materials Testing e

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Extrapolation of GDT Results to a DT Fusion Neutron Source for Fusion Materials Testing e. Tom Simonen, U. Calif., Berkeley 8 th International Conference on Open Magnetic Systems July 5-9, 2010 Novosibirsk, Russia. US Fusion Program (2010). Establish the Scientific Basis - PowerPoint PPT Presentation

Transcript of Extrapolation of GDT Results to a DT Fusion Neutron Source for Fusion Materials Testing e

  • Extrapolation of GDT Results to a DT Fusion Neutron Source for Fusion Materials Testing

    eTom Simonen, U. Calif., Berkeley8th International Conference on Open Magnetic SystemsJuly 5-9, 2010 Novosibirsk, Russia

  • US Fusion Program (2010)

    Establish the Scientific BasisBurning Plasma (ITER)Plasma Control (DIIID, EAST,KSTAR, JT60)Materials Science Plasma Material InteractionsNeutron Material Interactions..

  • US Mirror AssessmentStimulated by new Gamma-10 and GDT ResultsFormed a Mirror Study Group (Virtual Meetings)10 Institutions, 25 individualsHeld Two WorkshopsPhysics and TechnologyHeld a Magnetic-Mirror Mini-ConferenceAt 2009 American Phys. Society DPP MeetingParticipated in Numerous DOE Planning MeetingsProposed International CollaborationsRussia, Japan, ChinaTutorial Talk at 2010 APS MeetingDmitri Ryutov

  • ITER is under Construction China, EU, India, Korea, Japan, Russia, US(

  • FUSION CHALLENGES (Sci.Am., March 2010)Before fusion can be a viable energy source, scientists must overcome a number of problems.

    Heat: Materials that face the reactions must withstand extremely high temperatures for years on end.

    Structure: The high-energy neutrons coming from fusion reactions turn ordinary materials brittle.

    Fuel: A fusion reactor will have to breed its own tritium in a complex series of reactions.

    Reliability: Laser reactors produce only intermittent blasts; magnet based systems must maintain aplasma for weeks, not seconds.

  • Fusion Neutrons Damage Materials

  • Fusion Materials Must Withstand Neutron BombardmentThree Options toQualify Materials:Accelerator Based (coupons) Mirror Based (Blanket Sub-modules}Tokamak Based (Blanket Modules)

  • RTNS Accelerator Facility(US Rotating Target Neutron Source)

  • RTNS Accelerator

  • IFMIF Design by EU & Japan

  • Tokamak Component Test Facility (US Design)

  • Tokamak Fusion Nuclear Science Facility (US Design)


  • 1980s Mirror Based Neutron Source Designs

  • Axisymmetric Magnetic MirrorGas Dynamic Trap (GDT) ConceptA.A. Ivanov, Fus. Sci. & Tech. 57, (2010), 320

  • GDT Schematic

  • GDT DD-Neutron Axial Profile(Agrees with Computer Simulation)

  • Electron Temperature vs Time(End Expansion = 100)*- H-plasma n 1.5 x 1013 cm-3 with H-NBI- H-plasma n 2.5 x 1013 cm-3 with H-NBI- D-plasma n 2.53 x 1013 cm-3 with H-NBI- H-plasma n 1.2 x 1013 cm-3 with H-NBI min gas puff- H-plasma n 3 x 1013 cm-3 with D-NBI- H-plasma n 3.53 x 1013 cm-3 with H-NBI

  • Neutron Flux Increases with Te(Now GDT Te = 0.25 keV so Flux = 0.4 MW/m2)(ITER Goal = 0.5 MW/m2, Fluence = 0.3 MW-yrs/m2)

  • A Russian Neutron Source DesignA MW of Fusion Power for Weeks

    Neutron Flux ~ 2 MW/m2 Test Area ~ 1 m2I

  • A DTNS Showing Magnets, Shielding ,Neutral Beams, and Material Samples(Bobouch, Fusion Science & Tech. 41 (2002) p44)

  • With Todays GDT ElectronTemperature (0.25 keV)

    DTNS Neutron Flux 80% of ITER

    DTNS Neutron Fluence in One Year Exceeds that in ITERs LifetimeNote: DTNS does Not Address ITERs Burning Plasma Physics or Full-scale Blanket Module Testing

  • Design DTNS from GDT ResultsSame Physical SizeL, rHigher Mag. Field, NBI Energy and Power1.2 T, 80 keV, 40 MWSame Dimensionless ParametersBeta, B(z), L/ai, r/ai, Te/Ei

  • Same-Size & Dimensionless Scaling

    GDTDTNSB, Tesla0.31.0Eb, keV2080Pb, MW530Beta (%)6060Mirror Ratio, R1717Length, & Radius, cm7 00 , 6700 , 6Radius / Gyro-radius22Debye Length, 10-3 cm22Te/Eb , %11Collisionality51 Marginalf(pe)/f(ci)60.6 More Microstablev(b)/v(Alfven)1.60.5 More Alfven Stab

  • A Possible Next Step

    A Phased Approach (Physics >> PMI >> D-T Neutrons) B = 0.6 Tesla 1 s NBI 40 keV 1 MW 1 s

  • Key DTNS Scientific IssuesIncrease Electron TemperatureNow Te ~ 0.25 keV (0.4 MW/m2 neutrons)Demonstrate Te > 0.5 keV (80 keV NBI)Confirm MHD Stabilization PhysicsDiagnostics and SimulationEvaluate DTNS DesignSimultaneous Neutron and PMI Testing?

  • Key DTNS Technical IssuesHigh Neutral Beam Power Large Tritium Recycling

    Consider Simple Tandem-Mirror Concept (GDT-SHIP concept)Small Axisymmetric End-Cells Reduce Plasma End LossesReduces overall neutral beam power Reduces Tritium Recycling

  • A Tandem-Mirror Neutron Source (TNS) (Based on TMX Data and the GDT-SHIP Concept)

  • TNS FeaturesPlug to Center-cell density ratio4To reduce end loss 4-foldPlug Mirror ratio3To reduce AIC and loss cone sizePlug NB injected at mirror ratio 1.3For AIC StabilityNeutral Beam Power (MW)20Half of DTNS

  • TNS ParametersMaximum Miagnetic Field, 20 TeslaPlug Mirror Ratio, 3Central-Cell Magnetic Field, 1.2 TeslaCentral-Cell NBI Power, 10 MWEnd-Cell NBI Power, 5 MW eachElectron Temperature, 2 keV

  • TNS Challenges(GDT-SHIP can address many issues)Electron TemperatureMHD Stability at Higher TeEnergetic Ion iMicro-stabilityTritium RetentionDetailed Modeling Needed

    GDT SHIP can address many issues

  • SummaryA DT Neutron Source (DTNS) can have the same Physical-Size and the same Dimensionless -Size as GDTA Simple Tandem Mirror Neutron Source (TNS) Reduces Tritium Reprocessing 4-fold and Reduces the Neutral Beam Power 2-fold.

  • We Can Produce 1 MW of Fusion Power Sustained for Weeks within 10 Years

    Purpose: Test materials & SubcomponentsDemonstrate sustained fusion power Features:Based on recent GDT ResultsLow Tritium Consumption,No tritium Breeding RequiredSimple Construction Geometry.