Arbeiter, F.

Aubert, J.

Barrett, T.

Domalapally, P. K.

Özkan, F.

KITopen

KIT – Universität des Landes Baden-Württemberg undnationales Großforschungszentrum in der Helmholtz-GemeinschaftInstitut für Neutronenphysik und Reaktortechnik, Gruppe Messtechnik und experimentelle Methodik (INR-MET)www.kit.eduLimits of First Wall and limiter PFCs in DEMOFrederik Arbeiter (KIT),  Julien Aubert (CEA), Tom Barrett (CCFE), Phani Kumar Domalapally (CV-Řež), Furkan Özkan (KIT) - 02.12.2014, EFPW, Split.Institute for Neutron Physics and Reactor Technology2 02.12.2014Heat loads on the First Wall (FW)Frederik Arbeiter, Limits of FW/Limiter PFCs, EFPW-2014, SplitPlasma (in AUG)First WallDEMO HCPB design, D. Carloni et al.Surface heat fluxqw=500kW/m² ...?Institute for Neutron Physics and Reactor Technology3 02.12.2014Simple maths on FW cooling / thermohydraulicFrederik Arbeiter, Limits of FW/Limiter PFCs, EFPW-2014, SplitwqMaximum (outlet) coolant temperatureMaximum plasma-facing wall  temperatureSimplified 1D, steady stateNecessary pumping power –substracts from net output !heat transferfluid - wallheat conductioninside wall,2 ,1( ) ( )pfw b pfmf mfi pq q L wT Tm c     bq0.8wf ih m 32 22fl i pfpumppump fl h c pumpV p m L fPd A        , ,max ,2 /w ww p mfwf w wq qT Th t   ߣ௪Mass flow rate in single channelBulk fluid temperature at inlet / outletHeat conductivityof wall materialሶ݉ ௜Tmf,1/2Institute for Neutron Physics and Reactor Technology4 02.12.2014Simple maths on FW mechanicsTemperature gradient induced bending stressPressure induced bending stress (rect. channel)Frederik Arbeiter, Limits of FW/Limiter PFCs, EFPW-2014, Splitߪ௕,஽் ൌ12⋅ ܥܶܧ ⋅ ܧ ⋅Δܶ1 െ ߥൌ12⋅ ܥܶܧ ⋅ ܧ ⋅ݍሶ௪ ⋅ ݐ௪ሺ1 െ ߥሻ ⋅ ߣ௪ܥܶܧܧߥߣ௪Coefficient of thermal expansionYoung‘s modulusPoisson ratioHeat conductivityߪ௕,ூ௉ ൌߚଵ ⋅ ݓ௖௖ଶ ⋅ ݌௜ݐ௪ଶ, ߚଵ=0.5Both stresses act alignedat the channel sides:• compression near plasma,• tension near cooled faceInstitute for Neutron Physics and Reactor Technology5 02.12.2014Range of real material data(Data at 400°C) 9%Cr RAFM(Eurofer, F82H)Tungsten (Plansee)Copper alloys(CuCrZr-IG)Thermal conductivity29 .. 33 W/m/K 135 W/m/K 352 W/m/K ** dep. on gradeHeat capacity c 5.12 J/K/cm³ 2.70 J/K/cm³ ~3.3 J/K/cm³Coeff. of therm. expansion11.7 µm/m/K 4.3 µm/m/K 18.2 µm/m/KYoung Modulus E 197 GPa 380 GPa 109 GPaPoisson ratio  0.3 0.28 0.34Yield stress Sy,min 416 MPa 420 MPa100 (after recryst.)189 MPaSm 154 MPa 80 MPaTemperaturewindow w/ irrad.> 300-350°C< 550°C> 600-800°C< 1150-1300°C> 250-285°C< 300-350°CFrederik Arbeiter, Limits of FW/Limiter PFCs, EFPW-2014, SplitOther candidates: Vanadium, SiC/SiCf, CuNiBe, TZM, W-Cu composites … Institute for Neutron Physics and Reactor Technology6 02.12.2014Material temperature window (Example: Eurofer)Frederik Arbeiter, Limits of FW/Limiter PFCs, EFPW-2014, SplitEurofer, DEMO-ISDC550°C40‘000hx 1.75Yieldstrength[MPa]x 1.5Creeprupturestrength[MPa]Gaganidze et al. 2007Materials have a temperature window:• lower limit defined by DBTT (shift by irrad.)• upper limit : Strength (Sy, Sr)16 dpaInstitute for Neutron Physics and Reactor Technology7 02.12.2014... even more constraintsThe FW cooling has to integrate with other component (Breeder zone, Divertor) cooling systems and finally BoP, which needs high temperature sources forhigh efficiency (See more details EPFW-Talk by L.V. Boccaccini)The FW materials should not perform too bad concerning decay heat andactivation (Effect on remote handling and disposal)Frederik Arbeiter, Limits of FW/Limiter PFCs, EFPW-2014, SplitDEMO HCPB cooling topologyD. Carloni et al.SC-Rankine cycle@ 49.88%M. Medrano, 2006Activation of divertor materials,Pereslavtsev et al. 2013Institute for Neutron Physics and Reactor Technology8 02.12.2014Example analysesFrederik Arbeiter, Limits of FW/Limiter PFCs, EFPW-2014, SplitCase Tm1[°C]Tm2[°C]Twf[K]Tw[K]Twmax[°C]50g/s, 3mm EF 300 345 103 48 495100g/s, 3mm EF 300 322 59 48 429150g/s, 3mm EF 300 315 43 48 405100g/s, 3mm Cu 300 322 59 4 385Thermal analysis examples:Base-case values:He @ 80bar, 500kW/m²h(50g/s) = 4858 W/m²/KLpf = 1000mm wpf=20mm„EF“ : Eurofer, „Cu“ : CuCrZr-IGStress analysis examples:Summative stresses frominternalpressure and thermal gradient are evaluated:Optimum for cover wall thickness exists.Institute for Neutron Physics and Reactor Technology9 02.12.2014Creep-Fatigue failureFrederik Arbeiter, Limits of FW/Limiter PFCs, EFPW-2014, SplitCreep-fatigue damage criteria TBM DEMOPulse number 30’000 20’000 (2nd blanket)Pulse length 400 s 2hCoolant pressure 80 bar 80 barFW design and temperature comparableBlanket and divertorcomponents work  under high thermo-mechanical loading. Creep-fatigue is one of the main failure modes.Institute for Neutron Physics and Reactor Technology10 02.12.2014Creep fatigue assessment (Aktaa et. al)Frederik Arbeiter, Limits of FW/Limiter PFCs, EFPW-2014, SplitAssessment Criteria ConservatismMat. Properties for EuroferTBM DEMOASME – elastic rules Very high available Not availableASME – inelastic rules High available Not availableAktaa – UMat Model Normal available Available but to be verified by experimental resultsIn addition to simple 3Sm rules  creep-fatigue assessment should be considered for DEMO and TBM design determining allowable number of cycles..Application of UMat model in TBM: Influence of hold time on damage450°C310°CInstitute for Neutron Physics and Reactor Technology11 02.12.2014Design example A : Helium cooled FW (HCPB or HCLL, KIT/CEA)Frederik Arbeiter, Limits of FW/Limiter PFCs, EFPW-2014, SplitHCPB TBM v2.1Ilić et al. 2013DEMO HCPBCarloni et al. 2013DEMO HCLLAiello et al. 2013HCPB-TBM v2.1 HCPB  2013 HCLL 2013Flow rate 110.8g/s, 84.6m/s 49g/s, 80m/s 73.9g/s, 80m/sheat flux density 500kW/m² 500 kW/m² 500 kW/m²PF length x width 2x 1290mm x 20mm 1006mm x 20mm 1512mm x 20.2mm Tmf1, Tmf2 300°C  360°C 300°C  330-340°C 300°C  372°Cheat transfer coeff. 6129 W/m/K @Rz20µm 5950 W/m²/K 5569 W/m²/Kpressure drop (*) 0.16 MPa 0.04 MPa 0.15 MPapeak temperature (*) 539°C 488°C 521°C(*) different calculation approaches / definitions may have been usedInstitute for Neutron Physics and Reactor Technology12 02.12.2014Study 2013 : Increase HTCFrederik Arbeiter, Limits of FW/Limiter PFCs, EFPW-2014, Split Effect of rib roughness or mixing devices was assessed by CFD@49g/sExample@49g/s, 750kW/m²:T=-139K !„G0“ : smooth „G7“ : waved ridge „G5“ : transv. rib „G2“ : V-shape ribHCPB DEMO „6.6mm“smoothwavedtransv.v-rib>>>.v-rib<<<Institute for Neutron Physics and Reactor Technology13 02.12.2014Extrapolated heat flux limitFrederik Arbeiter, Limits of FW/Limiter PFCs, EFPW-2014, SplitHeat Flux 0.5 MW/m² 0.75 MW/m² 1.0 MW/m²Coolant flow rate 74 g/s 154 g/s 293 g/sPressure drop gradient 0.09 bar/m 0.4 bar/m 1.43 bar/mpumping / removed heat 0.96 % 6.0 % 32 %Smooth surface, 3mm EF cover, T2=360°C, Tmax=550°C:Heat Flux [MW/m²] 0.5 MW/m² 0.75 MW/m² 1.0 MW/m²Coolant flow rate 33 g/s 70 g/s 132 g/sPressure drop gradient 0.05 bar/m 0.23 bar/m 0.84 bar/mpumping / removed heat 0.25 % 1.5 % 8.5 %Ribbed surface, 3mm EF cover, T2=360°C, Tmax=550°C:Heat Flux [MW/m²] 0.5 MW/m² 0.75 MW/m² 1.0 MW/m²Coolant flow rate 28 g/s 50 g/s 80 g/sPressure drop gradient 0.038 bar/m 0.12 bar/m 0.31 bar/mpumping / removed heat 0.15 % 0.6 % 1.9 %Ribbed surface, 1.5mm EF cover, T2=360°C, Tmax=550°C:Institute for Neutron Physics and Reactor Technology14 02.12.2014Design example B:Water cooled FW  (J. Aubert et al., CEA)Frederik Arbeiter, Limits of FW/Limiter PFCs, EFPW-2014, SplitEquatorial Outboardmodule• Eurofer as heat sink structural material.• Two separate cooling systems per module (FW/BZ): For safety and coolant regulation.• PWR conditions : Tin / Tout = 285°C / 325°C ; P = 155 bar.For efficient power conversion cycle • Toroidal counter current flow.• Double Walled.For reliability considerations from industrial feedback data base. To explore if needed or not !• Water velocity < 8m/s and diameter of pipes > 5mmTo prevent excessive pumping power (and corrosion ?)• Total thickness < 22 mm.To optimize TBR.• 2 mm W-armour (not taken into account in calculations)Institute for Neutron Physics and Reactor Technology15 02.12.2014WCLL FW parametric studyFrederik Arbeiter, Limits of FW/Limiter PFCs, EFPW-2014, Split• Parametric generation of model• 3D simulation of temperature and stress fields (Cast3M) for 2 load cases:• LC1 : normal condition :- Heat Flux, power deposition, 155 bar inside the tubes, 5 bar from the PbLi pool, end loads.• LC2 : faulted condition (pressurization of the box) :- 155 bar from the pbLi pool, end loads.• Decision OK/fail:• Stress assessment acc. to RCC-MRx, Pm<Sm, Pm+Pb<1.5Sm, Pm+Pb+Q<3Sm • Eurofer max. temperature 550°C• Creep and irradiation neglected for this studyInstitute for Neutron Physics and Reactor Technology16 02.12.2014WCLL FW ConclusionsFrederik Arbeiter, Limits of FW/Limiter PFCs, EFPW-2014, Split(The FW removes 100% of the Heat Flux + ~12% of the neutron deposition) Corrosion of Eurofer with water !A. Kanai et al. “Corrosion behavior of F82H exposed to high temperature pressurized water with rotating apparatus”. (2013) loss of 1µm of steel with v = 2,3 m/s during 100 h. Should increase with velocity and time.+    Effect of tritiated water ?=   1mm thickness in front of the plasma may be to thin > increase thickness > decrease Max HF ?!Heat Flux [MW/m²] 0.5 1 1.5Coolant Velocity [m/s] 2.8 4.9 7Power removed by the FW / Total power in the blanket [%]33 48 57Ratio pumping power / Removed heat [%] 0.1 0.12 0.17• Excellent capability for high heat fluxes.• Low pumping power, but PWR conditions limit potential for high therm. efficiency• Possible problem of corrosion and tritiation of water.• Outlook: Include Creep, Fatigue and Irradiated matl. prop. in analyses.Institute for Neutron Physics and Reactor Technology17 02.12.2014Effect of Tungsten armour on FW structural integrityT. Barrett et al., CCFE)Frederik Arbeiter, Limits of FW/Limiter PFCs, EFPW-2014, SplitBy FEA modelling, we can see that the presence of W Armour has a significant effect on FW structural stressWe compare two thermal-structural models1. Baseline WCLL EUROFER FW2. WCLL EUROFER FW + 2mm W armourLooked at the change in thermal and structural response of EUROFERWe find the W layer beneficially re-distributes some heat (peak temperature lower by ~5°C)Primary (pressure) stress is slightly improved by W armourSecondary (thermal) stress – 3Sm reserve factor reduced by 20-70% * by presence of W armourArmour castellations and a compliant interlayer will help lower this stress, but clearly this effect must be considered in design studiesFW model – no W armourFW model – with 2mm W armourInstitute for Neutron Physics and Reactor Technology18 02.12.2014Design example C: hypervapotron FW/limiter (CV-Řež)Frederik Arbeiter, Limits of FW/Limiter PFCs, EFPW-2014, Split• In ITER hypervapotrons are foreseen in the FW.• In the ITER FW CuCrZr is being used with low temperature coolant with a specified irradiation damage limit of 5.5 dpa.•  Very high heat transfer coefficients•  Using Eurofer as heat sink instead of CuCrZr will cause the same difficulties as in the case of the FW. Institute for Neutron Physics and Reactor Technology19 02.12.2014Hypervapotron technology for FW/limiterFrederik Arbeiter, Limits of FW/Limiter PFCs, EFPW-2014, SplitHypervapotrons might be considered for plasma limiter PFCsUsing Eurofer as heat sink instead of CuCrZr will reduce the heat flux performance to 1-2 MW/m² (not attractive)An attractive hypervapotron design seems difficult to realize when using Eurofer in PWR conditionITER FW DEMO limiterNeutron damage <5.5 dpa ~15 dpa/fpyTechnologySteel / CuCrZr structure with Be-tiles, water-cooledSteel or CuCrZr structure with castellated tungsten-armour, water-cooledOperating pressure 3 – 4 MPa [ITER PDD 2009]5-8 MPa (CuCrZr)15.5 MPa (Eurofer)Coolant temperature 70-100 °C [ITER PDD 2009]~220°C (as in DEMO Cu-alloy divertor)~300°C (Eurofer)Heat flux performance4.7 MW/m²~5 MW/m2 (CuCrZr)1-2 MW/m² (Eurofer)Institute for Neutron Physics and Reactor Technology20 02.12.2014ConclusionsHigh Heatflux FW/limiter designs can be produced5MW/m² hypervaporton (water) cooled / Copper1.5-2.5 MW/m² water cooled / Eurofer0.5-1.0 MW/m² helium cooled / EuroferUncertainty on wall heat flux must be limitednecessary safety factors evoke unattractive designs: (1) too much pumping power(2) too low outlet temperature for efficient electricity generation BoPIntegrated optimization approach for FW must be followedMaterial temperature windowsComplete stress assessmentIntegration with BoP... also TBR, manufacturing, and other issues!Frederik Arbeiter, Limits of FW/Limiter PFCs, EFPW-2014, Split

Limits of first wall and limiter PFCs in DEMO

https://publikationen.bibliothek.kit.edu/230098091/3816705

Limits of first wall and limiter PFCs in DEMO

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