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1 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 1 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum.

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Presentation on theme: "1 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 1 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum."— Presentation transcript:

1 1 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 1 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Corrosion of steels in liquid metals Concetta Fazio Program Nuclear Safety Research MATGEN IV.2 February 2- 8, 2009 Stockholm – Kiruna, Sweden

2 2 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 2 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Outline Motivation –The role of Nuclear Energy in an Energy Mix –The Fast Reactor System and its fuel cycle –Transmutation objectives and Scenarios Fast Reactor Systems and the role of liquid metals as coolant –Examples Loop type Na cooled FR Pool Type Pb cooled FR ADS Corrosion of steels in liquid metals –What is corrosion? –Parameters affecting corrosion –Corrosion mechanisms in HLM and Na –Experimental evaluation of corrosion mechanisms and rate –Models –Practical applications Summary and Perspectives

3 3 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 3 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) The role of Nuclear Energy in an Energy Mix Source IEA : Energy to 2050 - Scenarios for a Sustainable Future

4 4 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 4 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Objectives of future implementation of FR in a power park (starting from ~ 2040)

5 5 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 5 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Optimal resources utilisation …. G. Koch, Radiochimica Acta 37 (1984) 205

6 6 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 6 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Transmutation Objectives and Scenarios Generic objectives of P/T strategies: –reduce the burden on a geological storage in terms of waste mass minimization, reduction of the heat load and of the source of potential radiotoxicity.

7 7 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 7 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Transmutation Objectives and Scenarios More specific objectives can be defined according to the specific policy adopted towards nuclear energy and according to specific strategies of reactor development. Three categories of specific objectives: –Waste minimization and sustainable development of nuclear energy and increased proliferation resistance of the fuel cycle. A transition from a LWR fleet to a FR fleet is foreseen. –Reduction of MA inventory and use of Pu as a resource in LWRs, in the hypothesis of a delayed deployment of fast reactors. Use of dedicated burners (ADS or FR) –Reduction of TRU inventory as unloaded from LWRs: Management of spent fuel inventories, as a legacy of previous operation of nuclear power plants in ADS. It is a generally agreed conclusion that fast neutron spectrum systems are more appropriate for transmutation of TRU

8 8 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 8 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Transmutation Objectives and Scenarios

9 9 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 9 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Among the 6 preferred Gen IV systems, 3 are FRs Very High Temperature Reactor Sodium Fast reactor Supercritical Water ReactorMolten Salt Reactor Lead Fast Reactor Gas Fast Reactor

10 10 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 10 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Examples - Loop type Na cooled FR: JSFR Ref. SMINS, 2007

11 11 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 11 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Loop type Na cooled FR: JSFR Operational conditions K. Mukai, Int. Seminar on coolants and Innovative Reactor Technologies, CEA Cadarache Nov. 2006 Parameters to be considered for material assessment

12 12 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 12 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Examples - Pool type Pb cooled FR: ELSY L. Cinotti, Int. Seminar on coolants and Innovative Reactor Technologies, CEA Cadarache Nov. 2006 Pump Impeller Alternative materials for pump impeller under investigation Maxthal, SiSiC, Noriloy HX - T91 or AISi 316L Vessel – AISI 316L Cladding – T91

13 13 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 13 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Pool type Pb cooled FR: ELSY L. Cinotti, Int. Seminar on coolants and Innovative Reactor Technologies, CEA Cadarache Nov. 2006 Operational conditions Parameters to be considered for material assessment

14 14 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 14 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) ADS EFITXT-ADS

15 15 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 15 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) ADS: Operational conditions XT-ADS (LBE)EFIT (Pb) Core components: mechanical stresses: e.g. Hoop stress on cladding T300 – 500 °C400 – 530 °C dpaUp to 160Up to 100 flow~ 2m/s Reactor VesselT300 – 400 °C400 – 430 °C dpa< 0.02< 0.003 flow~ 1 m/s~ 0.1 m/s stress50-150 MPa80-150 MPa Heat exchangerT300 – 400 °C400 – 480 °C dpa< 0.02< 0.03 flow~ 1 m/s stress~100 MPa125-190 MPa Spallation targetT240 - 340 °C400 – 480 °C dpa/yrUp to 40Up to 30 flow~ 3 m/s~ 1.5 m/s stress~100 MPa + 40 fatigue cycles/yrn.a. EFIT Pump: T= 480 °C; dpa < 0.03; flow = 10 m/s (on impeller)

16 16 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 16 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Liquid Metals Fast reactors have: -Hard neutron spectrum (i.e. limited neutron thermalisation and as small neutron capture as possible) -High power density: need for effective coolant with high thermal exchange capability. Therefore: liquid metals as coolant. Historically Na and, at a lesser extent, Heavy Liquid Metals (HLM) have been the preferred choices.

17 17 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 17 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Liquid Metals Properties PropertyUnitNaPbLBE Atomic Number-1182- Atomic Massamu23207- Melting Temperature°C98327125 Boiling Temperature°C88317451670 Density at 450°Ckg/m 3 8451052010150 Thermal Conductivity at 450 °C W/mK691714 Chemical reactivity-HighModerate as dust Toxicity-High

18 18 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 18 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Corrosion of steels in liquid metals What is Corrosion? Why it is important to study it?

19 19 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 19 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) The word corrosion denotes the destruction of metal by chemical or electrochemical action; a familiar example is the rusting of iron U. R. Evans Pitting Corrosion: Corrosion Pits are the primary source of leaks in water handling systems Liquid metal corrosion Lecor impeller (presented at the ELSY Meeting by ENEA) Active Corrosion on Carbon Steel Manhole

20 20 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 20 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Why it is important to study it -Ensure Integrity of structures -Avoid Plugging of systems with corrosion products -Ensure thermal conductivity of fuel cladding and functional components An example for HLM cooled FR: Stringent safety requirement on the integrity of the cladding material has been put for design basis operating conditions and design extension conditions. For the chosen temperature regime, the selected cladding material should withstand the combined effect of neutron irradiation, corrosion and mechanical stresses in order to comply with the safety requirements.

21 21 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 21 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Factors affecting liquid metal corrosion Temperature Temperature gradient (mass transfer) Cyclic temperature fluctuations Surface area to volume ratio Chemical purity of the liquid metal (wetting) Flow velocity (Reynolds number) Surface conditioning (surface films) Number of materials in contact with the same liquid metal (dissimilar mass transfer) Condition of the container material (carbides or nitrides at the grain boundary)

22 22 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 22 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Liquid metal corrosion mechanism Alloying between liquid and solid metals: for this type of mechanism there must be some solubility of the liquid metal in the solid metal. In some cases the liquid metal dissolves considerably in the solid metal with the formation of an intermetallic compound (e.g. V in Pb at 1000°C). Scheme of the simple dissolution mechanism Simple solution attack: Removal of the metal from the surface to saturate the liquid metal. Concentration gradient mass transfer dissimilar metals, e.g: Mo samples tested in Na contained in a Ni crucible at 1000°C: Ni had transferred through the Na and deposited on the Mo surface to produce Ni-Mo compounds

23 23 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 23 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Liquid metal corrosion mechanism Temperature gradient mass transfer: the most damaging type of liquid metal corrosion is temperature gradient mass transfer. The driving force for temperature gradient mass transfer is the difference in solubility of the dissolved metal at the temperature extremes of the heat transfer system. By knowing the solubility limit of the solid in the liquid metal the driving force of these phenomena can be determined Pulg in an Inconel- Pb loop

24 24 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 24 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Part 2: Factors affecting liquid metal corrosion Temperature Temperature gradient (mass transfer) Cyclic temperature fluctuations Surface area to volume ratio Chemical purity of the liquid metal (wetting) Flow velocity (Reynolds number) Surface conditioning (surface films) Number of materials in contact with the same liquid metal (dissimilar mass transfer) Condition of the container material (carbides or nitrides at the grain boundary)

25 25 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 25 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Liquid metal quality: Sources and type of impurities At installation start up and in normal operating conditions –From Cover gas and adsorbed gases on structures (O 2, H 2 O) –From neutron reaction and from spallation (e.g. Po, Hg, other activation products) –Corrosion products from structural material (e.g. Fe, Cr, Ni, etc.) –Intrinsic impurities (Ag, Cu, Sn, etc.) Off normal conditions –From Fuel cladding failure (Pu, U, MA, etc.) –Air entrance (N 2, O 2, H 2 O,..) –Steam entrance (H 2 O)

26 26 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 26 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) HLM quality control: the case of Oxygen Above solubility limit lead and bismuth oxide formation Solubility of Oxygen in LBE Solubility of Oxygen in Pb Oxides floating on the liquid metal

27 27 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 27 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Na quality control: the case of Oxygen

28 28 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 28 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Solubility of metallic elements In Na In HLM

29 29 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 29 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) From liquid metal quality to corrosion Liquid metal corrosion depends from the solubility of the solid metal in the liquid metal and its solution rate. Solution rate and extent of solubility are affected by –formation of surface intermetallic compounds (among the liquid and the solid) –oxide or nitride films formation (due to the presence of oxygen / nitrogen in the liquid metal) –Other impurities present in the liquid metal can increase the solution rate –Temperature gradients and multimetallic systems

30 30 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 30 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Results from screening experiments: HLM 10000 h 20 m PbBi ferritelayer 20 m PbBi Case 1) oxygen content in LBE < 10 -9 wt.% T=400 °C Dissolution of solid metal in the liquid metal Uniform dissolution Transgranular and intergranular Leaching of Ni and ferritisation AISI 316L T91 Case 2) [O 2 ] LBE > 10 -8 wt.% and < 400 °C < T < 550 °C (PbO)GΔ O 2 Impurities in LBE forming simple or complex substances on the metal surface Under controlled O 2 content and T: the oxide can be considered as a corrosion protection layer AISI 316L 2) 1) Corrosion mechanism in HLM depends from: Temperature – oxygen content in the liquid metal – composition of steel

31 31 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 31 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Results from experiments: Na Low Oxygen High Oxygen Similar mechanism is observed with Cr (Na-Cr-O are more stable than Na- Fe-O) Formation of ternary oxides increased corrosion rate In austenitic steels ferritisation can be observed (Ni solubility highest)

32 32 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 32 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Experimental Programs to address Corrosion mechanism and rate

33 33 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 33 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Choice and characterisation of reference structural materials: the case of HLM systems Materials selected –Ferritic Martensitic steel T91 for the highly loaded parts (e.g. cladding, spallation target) –Austentic steel AISI 316L for e.g. Vessel –Fe, Al based corrosion protection barrier ElementCrMoNbNCV wt. %8-9,50.85-1.050.06-0.10.03-0.070.08-0.120.18-0.25 ElementMnPSiNiAlS wt. %0.30- 0.60 <0.020.2-0.5<0.4<0.04<0.01 T91 ElementCrMoNbNCV wt. %16-182-3-0.10.03- ElementMnPSiNiAlS wt. %20.0450.7510-14-0.03 AISI 316L

34 34 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 34 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Materials qualification program for HLM systems FZK CEA NRI ENEA CIEMAT FZK/IPPE Irradiation studiesCorrosion studies Corrosion / n-irradiation combined effect

35 35 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 35 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Corrosion studies in HLM Dissolution (uniform or transgranular) of the steel elements in the liquid metal Oxidation of the steel surface. The oxide layer can act as a protection barrier against a direct corrosive attack of the liquid metal HLM oxides precipitates causing hydraulics problems (e.g. plugging) Ellingham Diagram For the operating condition of XT-ADS (300 – 400°C) and EFIT (480 – 530 °C) respectively an appropriate oxygen potential can be selected to avoid HLM oxides formation and to promote oxidation of the steel surface. These are thermo-chemical statements, which enables to identify the corrosion mechanism. However, no information are available on the corrosion rate and the hydraulics effect.

36 36 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 36 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Corrosion studies: experimental results LoopExperimental conditions 2.000 h Oxide scale/LM attack Up to 10.000 h Oxide scale/LM attack T91316T91316 CORRIDA (FZK) LBE 550°C; 10 -6 wt.-%O flow= 2 m/s Oxide: 20-25 m Oxide : few Oxide: 45 m (data dispersion) LM attack up to 350 m CU2 (IPPE/FZK) LBE550°C; 10 -6 wt.-%O flow= 1.3 m/s Oxide: 39 m _____6600 h Oxide: 36-45 m (data dispersion) _____ CHEOPE III (ENEA) Pb 500°C; 10 -6 wt%; flow = 1 m/s 20 m (non homog.) Oxide: few5000/10000 h Oxide: 25 m / scale spall off 5000/10000 h Oxide: thin/thin and compact LINCE (CIEMAT) LBE450 °C; 10 -8 wt.-%O (probl. on sensor) 1700 h T91: 4 m (non homog. oxide) UnaffectedCorrosion attack up to 350 m Corrosion attack up to 200 m LECOR (ENEA) LBE450°C; 10 -10 -10 -8 wt% LM attackless evident LM attack _____

37 37 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 37 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Corrosion studies: experimental results CORRIDA FZK Oxide: 25 m 550°C; 10 -6 wt.-%O flow= 2 m/s No magnetite detected (higher velocity) 550°C, 10 -6 wt.-%O flow= 1.3 m/s Oxide thickness: spinel+ internal oxidation = 22 µm Magnetite thickness: 17 µm CU2 IPPE/FZK Oxide: 39 m Results after 2000h in LBE at 550°C and Pb at 500°C performed with a controlled oxygen potential 500°C, ~10 -6 wt.-%O flow ~ 1 m/s 1.Lower temperature 2.Different oxygen potential 3.low flow velocity CHEOPE /ENEA Oxide: ~ 20 m 1.Oxide scale is formed by three layers: outer magnetite – intermediate Fe, Cr spinel oxide – inner oxygen diffusion zone 2.However, oxide scale tested in Corrida do not has the outer magnetite layer: Hydraulics effect (see next slide)? 3.After 2000h oxidation rate in Pb at 500°C is lower with respect to LBE at 550°C: temperature effect

38 38 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 38 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Corrosion studies: experimental results Confirmation of hydraulics effects on the oxide scale formation: Experiment performed with different flow velocities 550 °C, 2000 h, ~10 -6 wt.% O At 1m/s outer magnetite scale, at 1,75 m/s small rests are visible, at 3m/s magnetite scale entirely eroded. FZK-IHM/IPPE collaboration Fe 3 O 4 V = 1 m/sV = 1,75 m/sV = 3,0 m/s (Fe, Cr) 3 O 4 Internal oxidation Fe 3 O 4 (Fe, Cr) 3 O 4 Internal oxidation (Fe, Cr) 3 O 4

39 39 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 39 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Corrosion studies experimental results 10 -6 wt.-%O flow= 1 m/s t=2000h 550°C Pressurised tube in HLM

40 40 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 40 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Example of application of corrosion results to Design (D. Struwe, W. Pfrang, IRS/FZK) Oxide layer thickness should be limited to less than 20-30 m in order to keep margin on the maximum allowable temperature for the T91 steel. Control of oxidation process in a reactor system might not be applicable GESA surface alloyed steel can be seen as a solution Axial profiles of clad inner temperature modified calculation with different additional oxide layers

41 41 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 41 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Corrosion studies: Fe, Al corrosion protection barrier 600°C Up to 600°C and 10000 h no corrosion attack and no visible oxidation. Thin alumina scales protect the surface alloyed steel. 1. LPPS of Fe, Al2. GESA treatment on the LPPS coating 1.Enhance metallic bonding with substrate 2.Smoother surface 3.Reduced Al content 500°C 550 °C 3. GESA treated samples tested for 10000 h in flowing LBE at three different temperatures, flow rate 1 m/s and oxygen ptential equivalent to 10-6 wt%

42 42 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 42 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Corrosion studies: Fe, Al corrosion protection barrier Confirmation of hydraulics effects on the Fe, Al GESA treated samples: Experiment performed with different flow velocities 550 °C, 2000 h, ~10 -6 wt.% O Samples with proper LPPS coating and proper GESA treatment: no flow velocity effect on surface appearance, no dissolution attack, no severe oxidation, no erosion. FZK-IHM/IPPE collaboration V = 1 m/sV = 1,75 m/sV = 3,0 m/s

43 43 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 43 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Oxygen activity: oxidation/dissolution Time, Temperature Flow rate: high flow rate erosion of Fe 3 O 4 Steel composition: high Cr content increased oxidation resistance. Stresses: hoop stress enhances Fe diffusion Parameters affecting corrosion of steels and modelling Effect of temperature, oxygen content and steel composition Effect of flow velocity

44 44 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 44 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Corrosion modelling: Example Na – steel system Oxygen content in Na and flow velocity have been identified as the two main variables affecting the corrosion rate. The corrosion mechanism is the dissolution. From experimental results two semi-empirical equations have been determined: For v 4m/s - the corrosion rate depends from the velocity For v 4m/s – the corrosion rate depends only from the oxygen concentration

45 45 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 45 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Structural material corrosion in a closed an-isothermal system as a nuclear reactor, 2 kinds of model are needed: –Mechanistic model: give the structural material life time h ox (t) or k p, h diss (t), j ox, j diss, using the physical-chemical data characteristic of the mechanism (D ox, D LM, S…) –Mass transfer model: give the system life time Vcorr/prec(x) (prediction of plugging in the loop), using the output of the mechanistic model (k p, k pr, j ox, j diss …) Data needed: –Mechanistic model is based on numerous specific experiments which can be partly performed in static conditions –Mass transfer model is based on long term experiments in LM closed loop –To develop these models, need of physical-chemical data as: D ox, D LM, S LM, k pr, k diss which are very difficult to obtain and important lack of data to supply the corrosion model j ox oxygen flux in steel; J diss Fe flux in steel, h ox oxide thickness, h diss dissolution thickness, D diffusion coefficient, S solubility limit, k ox oxidation constant k pr precipitation rate Corrosion modelling: Example Steel-HLM

46 46 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 46 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Corrosion modelling Example: Pb-Bi eutectic – steel system

47 47 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 47 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Perspectives Advantages of F/M steels with respect to austenitic steel: Better thermal properties: 1. higher thermal conductivity 2. lower thermal expansion ( can have impact on the dimensioning, see e.g. Japanese Sodium Fast Reactor, JSFR ) Lower Swelling However, experience on austenitic steels for the nuclear use is available Data AISI316L from AAA handbook; Data T91 from RCC-MR

48 48 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 48 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Perspectives Advantages of ODS alloys, with respect to F/M steels 9% Cr ODS RAFM steel has been developed for future fusion reactors and has shown very promising mechanical properties at high temperature R. Lindau et al., FZK …..but what about corrosion resistance of ODS steels?

49 49 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 49 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Summary For the development of nuclear energy, FRs provide solution to the key issues of sustainability and waste minimisation; Among the preferred systems of Gen IV three types of FRs and two among them are liquid metal cooled; In this respect corrosion issues have to be considered due to safety requirements; The corrosion control in HLM is more challenging when compared to Na; Current programs allow to consolidate and extend corrosion understanding and modelling; In future, new type of steels (e.g. ODS) can provide improved performances. These materials need to be characterised also for their corrosion resistance

50 50 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 50 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Selected References Na H.U. Borgstedt, C.K. Mathews, Applied Chemistry of Alkali Metals, Plenum, New York, 1987. K. Fink, L. Leibowitz, Thermodynamic and Transport Properties of Sodium Liquid and Vapor ANL/RE-95-2, January 1995 (www.insc.anl.gov) M. Konomura, M. Ichimiya Design challenges for sodium cooled fast reactors J. Nucl. Mat. 371 (2007) 250–269 HLM Handbook on Lead-bismuth Eutectic Alloy and Lead Properties, Materials Compatibility, Thermal-hydraulics and Technologies issued by the OECD-NEA and available at the following link: http://www.nea.fr/html/science/reports/2007/nea6195-handbook.html Nuclear Technology September 2004 – Vol. 147, No3 Several Issues of J. Nucl. Mater (Vol. 296 (2001); Vol. 301 (2002);Vol. 318 (2003); Vol. 335 (2004), etc.) Comparative assessment HLM - Na Comparative assessment of thermo-physical and thermohydraulic characteristics of Pb, LBE and Na coolants for fast reactors, IAEA TECDOC – 1289, June 2002 F/M Steels High-Chromium Ferritic and Martensitic Steels for Nuclear applications, Ronald L. Klueh and Donald R. Harries, ASTM, MONO3

51 51 | Vorname Nachname | Mid-term Review NUKLEAR | February 5-6, 2007 51 | C. Fazio | MATGEN IV.2 | February 2009 KIT - Die Kooperation von Forschungszentrum Karlsruhe GmbH und Universität Karlsruhe (TH) Thank you for your attention


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