iiia 2 kondo liquid metals

7/28/2019 IIIA 2 Kondo Liquid Metals

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Improvement of compatibility ofliquid metals Li and Pb-17LI

Masatoshi KONDO, Minoru TAKAHASHI b), Teruya TANAKAa),Tsisar Valentyn c) and Takeo MUROGA a)

Tokai university, Japan,a)National Institute for Fusion Science a)b) Tokyo Institute of Technology, Japanc) Physico-Mechanical Institute of National Academy of

Sciences of Ukraine, Ukraine

ISLA2011


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3

Background -2

(Structural material)

Corrosion of RAFM steel

in liquid metals

Chemical reaction of steels base metal

(Fe), alloying elements (Cr, W) andcarbides with liquid metals

wt% Cr W C Mn Other Fe

-1 1.94 0.09 0.49 V: 0.2 balance

Chemical composition (wt%)

Reduced activation

ferritic martensitic steel iscandidate structural

material of blanket.

1m

Prior austenite grain boundary

Packet

boundary

Lath

boundary

Some

sub grains

Block

boundary


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Purpose

Purpose of the present study is follows;

- Establish corrosion test technology for liquid Li

and Pb-Li

- Make clear the corrosion characteristics ofRAFM JLF-1 steel in the liquid metals

- Make clear the corrosion of coating in the liquid

metals

- Modeling of the corrosion of RAFM steel in the

liquid metals


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Experimental procedure (1)

Fe Cr W NiLi 0.85 0.12 0.31 0.8 Nitrogen: 65

Pb-17Li 2.2 0.17 0.52 1.3 -

Pb-17Li provided by santoku coop.

Temperature 600C Time(hours) Re for mixing - MaterialLi

Static 30-250-750High purity, Li3N dope

Li2O dope, C dope

JLF-1

Er2O3 coat

Flowing 250 2859 High purity JLF-1

Pb-17LiStatic 250-3000 High purity

JLF-1

Er2O3 coat

Flowing 250 18512 High purity JLF-1

Initial impurity of liquid metals (wppm)

Experimental condition

Carbon Li2O Li3N


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Experimental procedure (2)

Influence

of flow

3cc

100cc

Fixed specimen

Width of impeller 33Rotation speed 100 rpm

Velocity around specimen v==0.17cm

Re number for mixing

2nd

=Re

48mm

Static test

(Simple immersion)

Flowing test

(Mixing vessel)


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(c) Impurity analysis of liquid breeders by ICP-MS( Fe, Cr, W, non metal impurity)(To investigate mass balance between loss in

specimen and increase of metal impurity in melt )

(b)SEM/EDX analysis for surface and cross section(To evaluate the metallurgical change of steels)

(a) Weight loss measurement

(To estimate the corrosion (loss) rate)

Analysis of corroded specimen

Take out

sampleLi immersion

at 350C Acetone

Immersion to

ethanolAcetone

Immersion to

ethanol

Cleaning procedure for tested specimen

Specimen in Li

Specimen inPb-Li


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Experimental results (Mass loss of specimen by corrosion in Li)

- The influence of non-metal impurity (i.e. nitrogen and oxygen) in

liquid Li was large on the corrosion loss.

- The Influence of oxygen in Li on the corrosion was newly found.)

-2

0

2

4

6

8

10

12

14

Li

(+0.8wt%Li2O)(Static)

750-hour

Li

(+0.5wt%Li3N)(Static)

250-hour

Li

(Pure)(Static)

250-hour

Li

(Pure)(Flow)

250-hour

Li

(+3.7wt%C)(Static)

250-hour

Weightlos

sofspecimens

(g/m2)


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Experimental results (Lithium)

20 hour 120 hour 250 hour

+0.5wt%Li3N nitrogen dope (Cr dissplution)

1m 20m 20m

250 hour

Phase

transformation

BCTa a

c

a a

a

BCC

C Fe

Phase transformation

Initial

122 hour 780 hour287 hour

+0.8wt%Li2O oxygen dope (Cr dissolution)+3.7wt% carbon dope

1m 1m 1m

Phase

transformation

No phase

change


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0

20

4060

80

100

0 10 20 30Erconcentration

inLi

unit:wppm(ICP-MS)

0 10 20 30

exposure (hour)

600C

Er2O3/JLF-1

Surface color was black after

the corrosion test though the

color was metallic luster

before the test.

m

normal

Corroded

(Er-Cr rich)

Peeling off

Crack

-0.1

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0 50 100 150 200 250Thermallin

earexpansion%

Temperature (C)

Li

JLF-1

Er2O3

Corrosion of Er2O3 coating in Li

The oxide itself might be chemically stable in the liquid breeders. The damage was possibly

made by a large difference of the thermal expansion ratio between adhered Li and the coatingduring a heat up and a cool down procedure of the corrosion test when the Li was solidified.


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Summery for corrosion in Li

- Nitrogen dissolved in Li has big influence onthe compatibility. It was newly found that

oxygen in Li can increase the corrosion of

steel. The nitrogen and oxygen dissolved as

non-metal impurity in Li must be removedbefore the use. Carbon in Li can suppress the

the depletion of carbon in the steel.

- The issue for the coating of liquid blanket isthe peeling of the coatings in the liquid metals.


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Experimental results (Weight loss of specimen in Pb-Li at static condition)

Corrosion was suppressed when the metal element, i.e. Fe and Cr, in

Pb-17Li was saturated..


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Experimental results (Pb-17Li)

600oC 750 hours

High mag. (x3000)

20m

5m

Low mag. (x1000)

600oC 3000 hours

20m

5m

High mag. (x3000)

Low mag. (x1000)

The corrosion in JLF-1 was selective attack to some boundaries of microstructure.


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Experimental results (Corrosion of Er2O3 coating in Pb-Li)

20m20m20m

Er

Fe

CrCountnumber

Resin Pb-Li Steel matrix

020 40 60 80

Depth (m)

The oxide itself might be chemically

stable in the Pb-Li.

The damage of the coating was

possibly made by a large difference

of the thermal expansion ratiobetween adhered Pb-Li and the

coating during a heat up and a cool

down procedure of the corrosion

test when the Pb-Li was solidified.

0

0.2

0.4

0.6

0.8

1

1.2

0 200 400 600

Temperature (C)

Themallinearexpansion(%)

Li

Pb

JLF-1

Er2O3


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Flowing Li

Internal diffusion of liquid metals

(FAC) (Erosion corrosion)

10m

Erosion- corrosion

was caused by

peeling of subgrains

after corrosion on

surface.

Flowing Pb-17Li

10m

Experimental results (Corrosion in flowing Li and Pb-Li)


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Corrosion modeling

Li (65wppm nitrogen) Pb-17Li Pb

Solubility

(Cs)

wppm

Molppm

Fe - * 47 (600C) ~ 34 (600C)

Cr52.4 (800 C) ~

94.3 (600C) 10 (500C) 1 (600C)

))V

hStexp(VCs(1m

C)-(CshJdt

dC

S

V

))V

hSt

exp(Cs(1C

Transient of metal

impurity in liquid

breeders

Corrosion ratio

Mass loss of specimen by corrosion

Concentration of metal in liquid breeders

Mass balance between increase of

metal impurity in liquid breeders andcorrosion ratio of specimen


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Mass transfer model in corrosion (Li)

Different corrosion device

600oC (Li)

Different geometrical factor

of corrosion systemVolume / corrosion surface area

V/S

Large

Small


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600o

C (Pb-Li)

Mass transfer model in corrosion (Pb- Li)


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Summery

Major conclusions are follows;

- Corrosion test technology for liquid Li and Pb-Li was

established.

- The corrosion characteristics of JLF-1 in static Li and Pb-Liwere investigated. Then, we started to study about the

corrosion in flowing condition.

-Modeling of corrosion of JLF-1 in Li and Pb-Li was started.

- Fundamental corrosion characteristics of anti corrosion

coating in liquid Li and Pb-Li was studied. The issue is the

peeling off of the coatings in liquid metals.


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Corrosion of Fe-Al coating in liquid Pb-Li

10m

Fe-Al

coating

316LPb-Li

Pb

O

Fe

Al

After 500- hour immersion in Pb-17Li at 600 degree C

Coating it self was chemically stable in liquid Pb-Li.

However, the peeling off is issues for the coating.

Now, study on metal plating technology is under going.


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Background -4

Corrosion phenomena

Solubility of metal elements and chemical potential of non- metal impurity

in liquid metals are important parameters which determine the corrosion.23

Compatibility

Liquid metal corrosion

Formation of corrosion products

(Carbides, oxides, nitrides, hydrides and so on)

-Dissolution of steel element

into liquid metals

-Diffusion of metal elements of liquid

metal into steel matrix

Determined by alloying process

Determined by chemical

potential of non-metal impurity

All liquid metals especiallyheavy liquid metal

Pb, Pb-Bi

Li, Na, K, Pb-Li(?)

GB attackErosion- corrosion

Peering of

corrosionproducts

FAC

At flowing

condition

At flowing static condition


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0.0001

0.01

1

100

10000

700 800 900 1000 1100 1200 1300

SolubilityofFeandCr

inLithium(

wppm)

Temperature of Lithium (K)

Cr in Li (Nitrogen 150wppm)[12]

Solubility of Cr in Li (Nitrogen


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