CORROSION OF STRUCTURAL MATERIALS IN LIQUID METALS …€¦ · · 2013-03-27corrosion of...

CORROSION OF STRUCTURAL

MATERIALS IN LIQUID METALS

USED AS FAST REACTOR

COOLANTS

FR’13, Paris, France|1F. Balbaud-Célérier, 2J.L. Courouau, 2L. Martinelli1DEN, DADN, CEA/Saclay, France, [email protected]

2Laboratoire d’Etude de la Corrosion Non Aqueuse, CEA/Saclay, France

| PAGE 1

USE OF LIQUID METALS AS COOLANTS FOR

NUCLEAR SYSTEMS

13 MARS 2013 CEA | FR’13, Paris, March 4-7, 2013 | PAGE 2

Pb-Li eutectic alloy (Pb-15.7 at.%Li): coolant and tritium breeder material of fusion

reactor

�reduced activation ferritic/martensitic steels, austenitic steels, ODS,

composites

Pb-Bi eutectic alloy (Pb-55 at.%Bi):

spallation target of Accelerator Driven Systems (ADS),

coolant of nuclear systems: Megapie, MYRRHA

� F/M steels, austenitic steels, ODS

Pb: coolant of lead fast reactors

� F/M steels, austenitic steels, ODS

Na: coolant of sodium fast reactors

� austenitic steels, F/M steels, ODS

Ga: plasma-facing material in fusion reactor, coolant

� austenitic steels, F/M steels

CEA | FR’13, Paris, March 4-7, 2013 | PAGE 3

THERMODYNAMIC DATA INTERESTING CORROSION

(1/3)

Solubilities of Ni in Pb and Fe in Ga and are few percents at 500°C but formation of intermetallics only in the Fe-Ga system

� Phase diagram permit to identify the stable species and the possible reactions thus the possible modes of corrosion BUT no notion of kinetics

T.B. Massalski (ed), Binary phase diagrams, 2nd edition,

ASM international, Materials Park, Ohio (1984)

-1200

-1100

-1000

-900

-800

-700

-600

-500

-400

-300

-200300 350 400 450 500 550 600 650

RT

lnP

O2

(kJ

.mo

l-1)

T (°C)

PbO

NiO

FeCr2O4

Cr2O3

Fe/Fe3O4Fe/FeO

FeO/Fe3O

Na2O

NaCrO2

Li2O

SiO2

Al2O3

13 MARS 2013 CEA | FR’13, Paris, March 4-7, 2013 | PAGE 4

Reaction between the liquid metal, the solid

material and dissolved impurities in the liquid alloy:

O, CE

Formation of oxides with the liquid metal: risk of

precipitation � process information

Stability of metallic oxides (existence of these

compounds given by phase diagrams) compared

to pure metals depending on T, dissolved impurity

concentration: dissolution or oxidation process

Identification of the constituents of the steels that

can improve the material corrosion behaviour:

Si, Al

� Possibility to form oxides in liquid Pb, Pb-Bi

� Possibility to form ternary oxides in sodium

� Possibility to control the behaviour of the steels

through the chemistry of the coolant


(2/3)



(3/3)

1.E-08

1.E-07

1.E-06

1.E-05

1.E-04

1.E-03

1.E-02

1.E-01

1.E+00

100 200 300 400 500 600 700 800

SF

e(w

t %

)

T (°C)

Fe(Pb)

Fe(Na)

Fe(PbBi)

Fe(PbLi)

Fe(Ga)

Solubility of iron in the liquid metals:

SFe(Ga) >> other liquid metals

Other solubilities in sodium and lead

alloys varying in two orders of magnitude

Tendency: SFe(Na) < SFe (Pb alloys)

� Thermodynamic data give the stable state

of the system BUT no information on the

kinetics of the reactions

Three main corrosion modes:

- Dissolution

- Formation of intermetallics

- Reaction with dissolved impurities in the liquid alloy

� Need for corrosion tests to acquire kinetic data and

identify the corrosion mechanisms

DISSOLUTION OF STEELS IN SODIUM AND LEAD

ALLOYS (1/2)

13 MARS 2013 | PAGE 6CEA | FR’13, Paris, March 4-7, 2013

Determination of empirical laws: engineering

approach, first choice of materials

1.E-03

1.E-02

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

1.E+05

0.001 0.0011 0.0012 0.0013 0.0014 0.0015 0.0016

Vco

rr (

µm

.yr-1

)

1/T (K-1)

Na high velocity range

Fe-Cr-Ni steels

[O] = 5 wppm

Pb alloys low velocity range

Fe-Cr-Ni steels

Pb alloys high velocity range

Fe-Cr-Ni steels

Pb-Li Fe-9Cr vPb-Li = 1 m.s-1

Pb-Li Fe-9Cr vPb-Li = 5 m.s-1

Na

304, 316FR, Mod Fe-9Cr steels

v = 2-4 m.s-1 T = 400-650 °C

[O] = 5 wppm

Lower dissolution rates in liquid

sodium: at 500 °C, the calculations

give a corrosion rate around 1

µm.yr-1 compared to 500 µm.yr-1 in

the high velocity domain in lead

alloys

BUT very important dispersion in

the results (several orders of

magnitude), the empirical laws are

restrictive to some materials in

specific conditions of [O], TE

No predictive capacity of these

models

� Need for more

fundamental approach to make

appropriate selections of materials and

guarantee their life durationsThermodynamics

CANNOT forecast the

corrosion kinetics even for

comparison between two

LM or two materials

Chopra, Tortorelli, JNM 122-123 (1984) 1201

Immersion of 316 in flowing

Pb-17Li

T = 455°C – t = 1400h

DISSOLUTION OF AUSTENITIC STEELS: Na, Pb-Li, Pb-Bi

Formation of a porous ferritic layer:

• Phase transformation from austenite to

ferrite due to a preferential dissolution of Ni

and Mn (completely depleted)

• Severely depleted in Cr. No [Cr] gradient

in the scale

[Cr] = 10 wt% at 495°C 4000h Barker, JNM 179-

181 (1991) 599-602

[Cr] = 5 wt% at 400°C and 450°C 3000h Broc, JNM 141-143 (1986) 611-616

[Cr] = 8 wt% at 450°C 4200h Coen, Fusion Eng.

Des. 14 (1991) 309-319

Immersion of 316L in Pb-Bi

T = 500°C – t = 3045h

COLIMESTA device – static test

Low oxygen concentrationE. Yamaki et al. Corr Sci 53 (2011) 3075

Formation of a porous ferritic layer:

• Phase transformation from austenite to

ferrite due to a preferential dissolution of Ni


• Severely depleted in Cr. No gradient of [Cr]

in the scale

[Cr] ≈ 5 wt% at 500°C from 200 h to 3000 h

BSE

20µm

Cross section of 304 steel in Na

T = 550 °C – t = 60000h + T =

600 °C – t = 20000h

CREVONA loop (KIT)Ganesan et al., JNM 312 (2003) 174

Formation of a porous ferritic

layer:

• Phase transformation from

austenite to ferrite due to a

preferential dissolution of Ni


• Severely depleted in Cr. No

gradient of [Cr] in the scale

[Cr] ≈ 5 wt% at 500°C from

200 h to 3000 h

Borgstedt, Proceeding of MATGEN-IV,

Cargese, France, September 24 - October

6, 2007

[Ni][Cr]

17

wt%

5w

t%0

wt%

11

wt%


0

0.5

1

1.5

2

2.5

3

3.5

0 1000 2000

h= 0.0072t

0

10

20

30

40

50

60

70

80

0 1000 2000 3000 4000

this study

Barker 495

Broc 400

Broc 400_2

Tortorelli 430

Tortorelli 450

Simon 500

Deloffre 500

Deloffre JNM_450

DISSOLUTION KINETICS: Na, Pb-Li, Pb-Bi

⇒ The thickness of the ferritic scale increases linearly with time

⇒ At the same temperature (500°C), corrosion rate of 316L in static Pb-Bi is higher

than in static Na (1 order of magnitude)

Time (h)

Thic

kness

of

the f

err

itic

laye

r (µ

m) Yamaki, 500

h

t

Time (h)

Thic

kness

of

the f

err

itic

laye

r (µ

m) 600°C

500°C

h=0.0009t

Pb-Bi, Pb-LiStatic Na

[O] = 1-2 ppm

Yamaki, Corrosion Science 53 (2011) 3075


SUMMARY OF THE RESULTS AND CORROSION

PROCESS OF AUSTENITIC STEELS

Ferritic

layer

Nis=NidreacJ

rrrr

)( LMDiff NiJr

LM penetrations316L

h

t)(Diff NiJ

Nid

[Ni] = 0 in the ferritic scale ⇒ dissolution occurs at the 316L/ferritic scale interface ⇒diffusion in the ferritic scale occurs via LM penetrations

Linear kinetics of the variation of the ferritic layer thickness as a function of time ⇒corrosion kinetics is not controlled by diffusion in the LM penetrations: diffusion in the

boundary layer or dissolution reaction

Diffusion flux in the boundary layer is much higher than the corrosion rate ⇒ the reaction

rate of Ni dissolution limits the corrosion rate: calculation of kd



Dissolution rate of 316L in Pb-Bi

(limitation by Ni dissolution): calculation of kd at 500 °C

Ni(316L) = Nidiss

kd

kpr

Nis=Nid reacJr

dt

thtRd

tR

C

xS

tCx

k

L

Ni )()(

)()(1

1316

316L

Ni

LBE

Ni

LBE

Ni316L

Ni

d

−

=

⇒ kd ≈ 3 x10-11 mol.cm-2.s-1

x

PbBi

Nipr

L

NidNi

corr

akakdt

dn

S−= 3161

L

Nix316 LBE

Ni

PbBi

Ni

S

C


Ratio of corroded area over

sample area: tends toward 1

thickness of corroded layer


OXIDATION OF STEELS IN PB-BI

0 500 1000 1500 2000 2500 3000 3500

0

2

4

6

8

10

12

14

16

18

20

T91

EP823

EP302

316L

316Lal

EM10

δ (µ

m)

t (h)

Steel Cr Ni Mo Mn V Nb W Ti Si C

Austenitic

316L

17.0 11.66 2.7 1.53 - - - - 0.42 0.022

Martensitic

T91

8.98 0.125 0.962 0.393 0.190 0.075 - - 0.351 0.086

Martensitic

EM10

8.97 0.07 1.06 0.49 0.013 < 0.002 < 0.002 0.01 0.46 0.099

Austenitic

EP302

16.0 10.0 - 0.8 - 1.0 - - 3.0 0.12

Martensitic

EP823

12.0 0.8 0.9 0.8 0.4 0.4 0.8 - 1.3 0.18

T = 470 °C

Oxygen concentration: 10-6 wt %

vPb-Bi = 1.9 m.s-1

F. Balbaud-Célérier et al, Journal de Physique IV 12 (2002)

Pr8 177.

( )( ) ( )

( ) ( )( ) taaKDaIaK

aKDvA

xh

aI

O

aIoxox

OII

b

Ov

oxox

Ovb

Mag

I

V

−

−+

+

+

−=

−− 3/2int3/2/

3/2int

3/2/

2

22

2

2

3/2

10

3

4

21

21ln

1610

3

4

Determination of a parabolic constant

allowing the calculation of the oxidation rate

for a given material, in the conditions of the

measurements:

Comparison of different steel compositions:

Si, Al effect

No information on the oxidation mechanism

� no long term prediction

Fundamental understanding of the

oxidation process to establish a corrosion

model

tkh p=

L. Martinelli et al, JNM 376 (2008) 282.


13 MARS 2013 | PAGE 12CEA | FR’13, Paris, March 4-7, 2013

CONCLUSIONS

Thermodynamic data give the stable state of the system, thecompounds susceptible to form but no information on the kineticsof the process

Need to perform corrosion tests in controlled conditions oftemperature, chemistry, hydrodynamics

Comparison of the materials behaviour: first selection of materials,optimisation of the composition

Fundamental work on the understanding of the corrosion processto develop corrosion models and predictive laws to guarantee thelong term behaviour

Direction : DENCommissariat à l’énergie atomique et aux énergies alternatives

Centre de Saclay | 91191 Gif-sur-Yvette Cedex

T. +33 (0)1 69 08 16 51| F. +33 (0)1 69 08 15 86

Etablissement public à caractère industriel et commercial | RCS Paris B 775 685 01913 MARS 2013

| PAGE 13

CEA | 10 AVRIL 2012

CORROSION OF STRUCTURAL MATERIALS IN LIQUID METALS …€¦ · · 2013-03-27corrosion of...

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