10-2. LBE-oxidation C,10-6 [O]wt%, 50N, 75µm, 10Hz 0, ,16. T T91+FeCrAlY+GESA ,14. Volume loss (mm³) 0, ,10

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1 Materials for ALFRED and ELFR selection and challenges A. Weisenburger, A. Gessi, A. Jianu, M. Del Giacco, R. Fetzer, A. Heinzel, G. Müller, P. Agostini - ENEA 10-2 Volume loss (mm³) 0,18 0,16 0,14 0,12 0,10 0,08 0,06 0,04 0,02 oxygen concentration in PbBi in wt% LBE-oxidation C OS 450 C,10-6 [O]wt%, 50N, 75µm, 10Hz T T91+FeCrAlY+GESA 10-8 experimental matrix C O(Fe3 O 4 ) Liquid metal corrosion 100T melt T max 700 temperature of PbBi in C Universität des Landes Baden-Württemberg und nationales Forschungszentrum in der Helmholtz-Gemeinschaft 0, Time (h) 100 h = 3.6x10 6 cycles

2 Materials for ALFRED and ELFR selection and challenges Outline Introduction Material selection Material compatibility Austenitic, ferritic/martensitic, alternatives Corrosion protection barrier development (GESA surface alloying process) Combined effects LM degradation corrosion/erosion, creep rupture, corrosion/wear Summary 2 Alfons Weisenburger HELIMNET Aix En Provence October 4-7, 2011 IHM/ / Campus Nord 2 FR13 IAEA conference in Paris March 2013

3 Liquid metal material interaction -Corrosion etc. Dissolutionof alloying elements into the liquid metal (W<<Fe, Cr<Ni) Solubility of steel elements in Pb / PbBi austenitic steel / solubility logs (wt%) Temperature ( C) Pb PbBi Ni Cr Fe Al Severe dissolution of alloying elements (Ni) dissolution rate up to 1 µm/h 3 Alfons Weisenburger HELIMNET Aix En Provence October 4-7, 2011 IHM/ / Campus Nord 3 FR13 IAEA conference in Paris March 2013

4 Liquid metal material interaction -Corrosion etc. Dissolutionof alloying elements into the liquid metal (W<<Fe, Cr<Ni) Mass transportof structural materials in the liquid lead alloys due to temperature gradients dissolution in hot areas and precipitation in colder regions (heat exchanger, cooler, pumps etc.) blocking of pipes Erosion of structural materials in dynamic (fast flowing) systems Liquid metal embrittlementat low temperatures (with and without irradiation) Measures to mitigate corrosion and associated effects 4 Alfons Weisenburger HELIMNET Aix En Provence October 4-7, 2011 IHM/ / Campus Nord 4 FR13 IAEA conference in Paris March 2013

5 Mitigation of steel corrosion formation of oxide scales This requiresoxygen in theliquid PbPbBi Oxygen control Oxygen level needs to be controlled to avoid PbO formation Liquid Metal corrosion T 1 Oxide scale on the steel surface prevent the dissolution steel Oxide scale on the steel surface prevent the dissolution a XT1 steel T 1 a XT1 oxide scale liquid metal T 1 > T 2 a XT1 > a LM > a XT2 liquid metal T 1 > T 2 a XT1 > a LM > a XT2 diffusion oxide barrier scalefor Cations! Alfons Weisenburger HELIMNET Aix En Provence October 4-7, 2011 IHM/ / Campus Nord 5 Technical Workshop - Safety and Design Aspects Petten 2013 RT ln p O2 (kj/mol) Or non soluble materials also ascoatings W, Ta require oxygen free Pb/PbBi T 2 a XT 2 oxide scale diffusion barrier for Cations! Temperature ( C) T 2 a XT2 oxide scale PbO in Pb 45 Bi 55 PbO 10-8 Cr 2 O 3 Ta 2 O 5 Bi 2 O TiO Temperature ( K) NiO 10-5 Fe 3 O 4 /FeO O [wt%] in Pb O [wt%] in Pb 45 Bi 55 from Orlov O [wt%] in Pb 45 Bi 55 our calc H 2 H 2 O p O2 (bar)

6 Materials for ALFRED and ELFR selection and challenges Outline Introduction Material selection Material compatibility Austenitic, ferritic/martensitic, alternatives Corrosion protection barrier development (GESA surface alloying process) Combined effects LM degradation corrosion/erosion, creep rupture, corrosion/wear Summary 6 Alfons Weisenburger HELIMNET Aix En Provence October 4-7, 2011 IHM/ / Campus Nord 6 FR13 IAEA conference in Paris March 2013

7 Components, materials and operating conditions ALFRED/ELFR Components Material Min./Max Temp. Normal Operation ( C) Max. Lead velocity (m/s) Max. Radiation damage (dpa/y) Max. Radiation damage (dpa) Reactor Vessel AISI316L < Inner Vessel AISI316L Steam Generator T91/AISI316L < Primary Pumps MAXTHAL (Ti 3 SiC 2 )? Coated T91 or SS (Aluminised, Ta)? < FA Clad FA Structures T91/15-15Ti / aluminized / /200 Dummy Assemblies T /200 Refueling Equipment AISI316L DHR Heat Exchanger T < Material C% Mn% Si% Cr% Ni% Mo% W% V% Nb% L 0, T austenitic f/m + ODS, Ti 3 SiC 2, Ta, Aluminized(GESA) 7 Alfons Weisenburger HELIMNET Aix En Provence October 4-7, 2011 IHM/ / Campus Nord 7 FR13 IAEA conference in Paris March 2013

8 Material compatibility of steels with Pb and PbBi austenitic steel / F/M steel / T91 oxide 200µm h 30µm Severe dissolution of alloying elements (Ni) dissolution rate up to 1 µm/h huge oxidation rate of F/M-9Cr-steels - frequent spallation of oxides due to growth stress - reduced heat removal capability Two major effects due to corrosion: Structural integrity metal recession dissolution, oxidation (Spinel + IOZ) Heat transfer/conduction -: oxidation (magnetite + spinel) 10µm scale 10K increase 8 Alfons Weisenburger HELIMNET Aix En Provence October 4-7, 2011 IHM/ / Campus Nord 8 FR13 IAEA conference in Paris March 2013

9 Austenitic steel (316L) in lead alloys long term tests 300 C h (LINCE - CIEMAT) h 450 C C 5000h (LINCE - CIEMAT) stagnant 550 C h (CORRIDA- ) LBE Ni depletion Fe LBE Bulk Material Bulk Material In LBE at low oxygen (10-8 wt%) > Fe3O4 300 C no signs of attack no severe oxidation 450 C Ni depletion - can not be used In LBE at normal oxygen (10-6 wt%) 450 C oxidation long term stability? 550 C severe dissolution can not be used 500 C h s (CHEOPE - ENEA) Pb In Pb at nominal oxygen (10-6wt%) 500 C protective thin scales 9 9 Alfons Weisenburger HELIMNET Aix En Provence October 4-7, 2011 FR13 IAEA conference in Paris March 2013 IHM/ / Campus Nord

10 Log C (%wt) Compatibility of 316L with Pb/PbBi OECD/HLM Handbook * 441 T (ºC) Oxidation Dissolution T e = ºC -8 t = h pure Pb [O] = wt% - saturation -10 T (ºC) Fe Fe-Cr-Ni steels in stagnant LBE 3 O -2 Useupto480 C in oxgyencontrolledpbseemsfeasable 4-14 Higher temperatures especially > C questionable 0,0010 0,0012 0,0014 0,0016 0,0018 0,0020 0,0022 PbO 1/T (ºK) -6 Useofcomponentsmadefrom316L O.K. 182 Log C (%wt) -12 Not many experiments at 500 C and below especially at proper oxygen Quite different results oxidation and dissolution observed at same conditions (localized dissolution attack) Duration of experiments? only very little Results for 15-15Ti similar only some numberofexperimentsareperformedin exposure tests performed Clear final statement difficult number of reliable test in Pb very little Most experiments have less Fuel than clad 3000 and h duration related structures require -8 additional measures long term prediction? -10 Oxidation rate? Fe-Cr-Ni steels in flowing LBE Oxidation Dissolution T e = ºC t = h [O] = wt% -14 0,0010 0,0012 0,0014 0,0016 0,0018 0,0020 0,0022 1/T (ºK) 10 Alfons Weisenburger HELIMNET Aix En Provence October 4-7, 2011 IHM/ / Campus Nord 10 FR13 IAEA conference in Paris March PbO Fe 3 O 4 182

11 9 Cr steel T91 compatibility with lead alloys 450 C h s (LINCE - CIEMAT) 480 C h s (IPPE/) 550 C (CORRIDA- ) 600 C 2000h LBE LBE Oxide layer Bulk Material In LBE at low oxygen (10-8 wt%) 300 C no signs of attack no significant oxidation 450 C 10µm oxide scales 50 µm 30µm 500 C h s (CHEOPE - ENEA) Pb In LBE at normal oxygen (10-6wt%) 480 C progressive oxide growth 30µm 6587h 550 C 1m/s progressive oxide growth 40µm h 550 C 2m/s progressive oxide growth no magnetite -~ 40µm 10000h In Pb at normal oxygen (10-6wt%) similar to LBE 500 C progressive oxide growth -32µm 10000h Only at high temperatures >550 C dissolution attack an issue Alfons Weisenburger HELIMNET Aix En Provence October 4-7, 2011 FR13 IAEA conference in Paris March 2013 IHM/ / Campus Nord

12 Oxide scale growth of T91 in PbBi10-6 wt% oxygen scale thickness [µm] T91 / 550 C / 10-6 wt% O Spinel (IPPE) SpinelMagn Spinel (COSTA) SpinelMagn Spinel (pressurized tube) SpinelMagn Spinel (velocity exp.) IPPE - spinel + magnetite SpinelMagn 0.5*t 0,5 CORRIDA metal recesion 21.3(log(t+267) *t 0,5 480 C 550 C IPPE - spinel 10-6 wt% C Corrosion/ dissolution not an issue for T components C but Zeit [h] At 550 C datafrom CORRIDA 2m/s and IPPE 1m/s In similiar range - if spread of data is considered Higher CORRIDA spineldata similar to IPPE spinel+ magnetite 0.5 t oxide scale thickness [µm] t t t T91 at different temperatures Parabolic oxidation safe approximation 40 x(t)=k Due 5 tto exessive oxidation/ reduced heat transfer Pb 500 C At temperatures above 550 C480 C measures to reduce oxidation required k(t): *(T[ C]) 480 C 450 C 420 C PbBi C 300 C time [h] 12 Alfons Weisenburger HELIMNET Aix En Provence October 4-7, 2011 IHM/ / Campus Nord 12 FR13 IAEA conference in Paris March 2013

13 MaxthalTi 3 SiC 2 / Ta compatibilitywithpb Ti 3 SiC h at750 C Ta h at500/550 C Ti 3 SiC 2 Formation of thin protective TiO 2 and mixed Ti, Si oxide scales No Pb attack and penetration Good corrosion resistance Erosion stability? Tested at time Ta Formation of non protective Ta 2 O 5 scales Hardening by oxygen diffusion degradation of mechanical properties Not suitable in oxygen containing Pb Pump coating will be investigated 13 Alfons Weisenburger HELIMNET Aix En Provence October 4-7, 2011 IHM/ / Campus Nord 13 FR13 IAEA conference in Paris March 2013

14 Materials for ALFRED and ELFR selection and challenges Outline Introduction Material selection Material compatibility Austenitic, ferritic/martensitic, alternatives Corrosion protection barrier development (GESA surface alloying process) Combined effects LM degradation corrosion/erosion, creep rupture, corrosion/wear Summary 14 Alfons Weisenburger HELIMNET Aix En Provence October 4-7, 2011 IHM/ / Campus Nord 14 FR13 IAEA conference in Paris March 2013

15 Corrosion barriers Al -containing surface alloys in-situ formation of thin slowly growing Al-rich oxide scale The procedure consists in two steps: (i) pre-coating the surface steel with Al-containing alloy (Fe-Cr-Al system) (ii) (ii) melting the coating and the surface layer of the steel using intense pulsed electron beams (GESA process Karlsruhe Institute of Technology). Magnetic coils GESA anode Electron beam parameter: electron energy: kev energy density : ~ 2 MW/ cm² pulse duration controllable: 1-200µs Beam diameter: 5-10 cm LPPS target GESA treatment leads to: metallic bonding pore removal surface smoothening and reduced Al content 15 Alfons Weisenburger HELIMNET Aix En Provence October 4-7, 2011 IHM/ / Campus Nord 15 FR13 IAEA conference in Paris March 2013

16 Pb/PbBi compatibility of perfect Al surface alloyed steel at optimal oxygen concentration 10-6 wt% 500 C 600 C HEAT EXCHANGER SPIRAL PIPES (top view) h h 20µm 20µm Up to 600 C and h no corrosion attack and no visible oxidation. Thin alumina scales protect the surface alloyed steel. 16 STEAM GENERATOR For ELFR spiral heat exchanger bending radius (strain) until cracks? 10% strain no cracks bending required is possible if Al < to 6 7 wt% 16 Alfons Weisenburger HELIMNET Aix En Provence October 4-7, 2011 FR13 IAEA conference in Paris March 2013 IHM/ / Campus Nord

17 Required Al content to from thin Al-rich oxide scales FeCrAl(Y) Bulk FeCrAl(400 C 550 C) Al-containing coatings (6-8 wt%) Summary Formation ofal-richscalesisprooved for all temperatures transition-aluminas are formed Seemtobe protective slowlygrowing Al ~ 6wt%-Cr~ 16wt%isrequired Cr-oxides reduces most likely inwards diffusion of oxygen Open issues: for further investigations Long term behavior: Stability of transition aluminas Transformation into stable α Phase Insitu tests in appropriate gas atmosphere Roleof Cr scaleformation Effectof RE Y, Hf, Zr, X.. Effectof microstructure GESA grain size after GESA treatment 17 Alfons Weisenburger HELIMNET Aix En Provence October 4-7, 2011 IHM/ / Campus Nord 17 FR13 IAEA conference in Paris March 2013

18 Materials for ALFRED and ELFR selection and challenges Outline Introduction Material selection Material compatibility Austenitic, ferritic/martensitic, alternatives Corrosion protection barrier development (GESA surface alloying process) Combined effects LM degradation corrosion/erosion, creep rupture, corrosion/wear Summary 18 Alfons Weisenburger HELIMNET Aix En Provence October 4-7, 2011 IHM/ / Campus Nord 18 FR13 IAEA conference in Paris March 2013

19 Examples for Erosion of 316L steel by fast flowing liquid Pb No erosion here No systematic investigation so far Specific flow patterns (turbulen, re-circulation) can result in severe material loss (erosion) Hastobe avoided Attack visualized at a cross section 19 Alfons Weisenburger HELIMNET Aix En Provence October 4-7, 2011 IHM/ / Campus Nord 19 FR13 IAEA conference in Paris March 2013

20 Influence of Pb on creep rupture strength Thresshold stress below which influence of Pb is neglectable GESA modified no influenceofpb Oxide scale hasto stay intact strain! Significant reduction of creep strength of T91 in contact with liquid Pb/PbBi Above certain stress/strain cracking of oxide scale Pb/PbBidirect contact to bare metal - reduces the surface energy and penetrates at the grain boundaries cracks along grain boundaries GESA modified FeCrAlY coating reduces eliminates the influence of Pb/PbBi No cracks no LBE influence 20 Alfons Weisenburger HELIMNET Aix En Provence October 4-7, 2011 IHM/ / Campus Nord 20 FR13 IAEA conference in Paris March 2013

21 Fretting wear - Time / 15-15Ti, T91, Aluminized Volume loss [mm³] 0,25 0,20 0,15 0,10 0,05 Number of cycles 0,0 7,2x10 6 1,4x10 7 2,2x10 7 2,9x10 7 3,6x10 7 T Ti GESA-T91 0, Time [h] - frettingdamage Nicontainingsteel -Nidepletioninthefrettedarea(alreadyafter150h) -Ni(Cr)depletedandPbenrichedcompactedscale contact Pb-bare surface of the alloy dissolution(t) - Fatigue cracks(cyclical load) deeper dissolution -Nifreesteelsbehavebetter nodissolution - Aluminized behave best COMPACTED SCALE Compacted scale 10 µm DISSOLUTION ATTACK BULK 10 µm 21 Alfons Weisenburger HELIMNET Aix En Provence October 4-7, 2011 IHM/ / Campus Nord 21 FR13 IAEA conference in Paris March 2013

22 Fretting Regimes allowed conditions - Test performed in severe (accelerated) conditions Combination LOAD AMPLITUDE typical of mix stick-slip regime or reciprocating sliding -N > 75 N / A < 15 µm STICK REGIME wear rate and specific wear coefficient 1 order of magnitude lower Specific wear coefficient [m 3 N -1 m -1 ] Gross slip regime Mix stick-slip regime Stick regime AIR -- Vigsbo-Söderberg Vingsbo-Söderberg 15-15Ti - 50 N T91-50 N GESA-T91-50 N Reciprocating sliding Amplitude [µm] Specific wear rate [m 3 N -1 m -1 ] Gross slip regime Air - Vigsbo-Söderberg Vingsbo-Söderberg [15] [*] 35 µm 75 µm 165 µm , Applied load [N] Mixed stick and slip regime Stick regime 22 Alfons Weisenburger HELIMNET Aix En Provence October 4-7, 2011 IHM/ / Campus Nord 22 FR13 IAEA conference in Paris March 2013

23 Summary Solubility, oxygen potential, dissolution and oxidation kinetics are key parameters for material compatibility Temperature limits for corrosion (dissolution) of steels in Pb/PbBi 316 type steels: T limit < 450 C might be 500 C in Pb to be assured T91 type F/M steels T limit < 550 C Oxidation of F/M steels above 450 C insufficient heat transfer capability oxygen control Large scatter in experimental data especially at higher temperature and longer exposure times understanding of phenomena and modeling for long term prediction needed Turbulent flow pattern severe erosion requires further investigation Ti 3 SiC 2 good corrosion properties erosion resistance to be tested Ta severe oxidation hardening not suitable in oxygen containing Pb 23 Alfons Weisenburger HELIMNET Aix En Provence October 4-7, 2011 IHM/ / Campus Nord 23 FR13 IAEA conference in Paris March 2013

24 Summary Direct contact with Pb reduces mechanical properties protective scales - creep rupture strength - LME (liquid metal embrittlement) at low temperature (< 350 C) Fretting has to be considered and should be minimized by design Surface protection of steels (LPPS FeCrAlY+ GESA) allows to increase the temperature limit above 550 C Selective thin Al 2 O 3 scales forming on top increase heat transfer capability and reduce corrosion attack mitigates reduction in creep rupture strength reduces amount oxygen to be added oxygen control easier We still have some work before Materials for ALFRED or ELFR are qualified E.g. verification of upper limit for austenitic steels Reliable production of surface barriers (GESA) Proof of long term and irradiation stability Fretting, Erosion, LM degradationxx? LM chemistry oxygen supply and control 24 Alfons Weisenburger HELIMNET Aix En Provence October 4-7, 2011 IHM/ / Campus Nord 24 FR13 IAEA conference in Paris March 2013

25 Thank you for your attention Thanks to all colleagues from LEADER project Thanks for EC for funding LEADER 25 Alfons Weisenburger HELIMNET Aix En Provence October 4-7, 2011 IHM/ / Campus Nord 25 FR13 IAEA conference in Paris March 2013