Mª. I. Barrena, J. Mª. Gómez de Salazar, A. Soria, L. Matesanz

Dpto. Ciencia Materiales e Ing. Metalúrgica. F. CC. Químicas. UniversidadComplutense de Madrid. UCM, Spain

M. Fernández and J. QuiñonesCIEMAT. Avda. Complutense, 22. 28040-Madrid, Spain

Production of Pb-Li eutectic:

cover gases or molten salts

during melting ?

Outline

•Rationale of the activity

•Review of current production techniques

•Design proposals

•Conclusions and future

Rationale -1

• Since early 70´s, Pb-Li eutectic (LLE, Pb15.7Li) represents today the most consolidate liquid breeder material.

• 6Li enriched LLE should be manufactured for diverse ITER TBM (EU-HCLL, US-DCLL, IN-LLCB) according to nuclear material standards.

• Several tones of Pb15.7(2)6Li should prospectively to be procure by ITER parties

• LLE characteristics should be established according to nuclear material QA requirements

– ISO3131/- 1, /-5, Light Metals and light alloying metal: methods for processing and treatment

• Li chemical activity determine LLE activity: title has large impact on NFT.

• 3H solubility in LLE would largely depends on Li-disproportioning by bad mixing or local aggregation.

– Other properties less modified

• 2 at% Li deviations are unacceptable from QA of LLE as Nuclear Material

- overestimation depending on the experimental protocole for production and for its determination

- W-T data for a total of 52 points {0 < xLi(at%) <22.2}, show to decrease smoothly from the melting point of pure Pb to the eutectic point (15.7(2) at% Li, 235(1)°C, the hypereutectic increased towards the m.p. of the PbLi phase [P. Hubberstey et al, JNM (1992)],

- a single liquid phase maintained over the composition range from 13.7 to 18.0 at% Li,

(3) eutectic disproportioning ()

Figure 4. Deviation from theoretical eutectic composition[15.7(2)at%Li] at liquid phase and solubilityimpact with Li aggregation.- not sistematically checked & driving

potentially to incorrect overestimatedsolubility (in connection with Li-aggregationby clustering)

- Mixing light Li with heavy Pb and largehomogeneity is not an easy technical mater

eut

LieutLiPbs

Ks

KsLiatLiatLnK

)()).(..(1)(

17

Uncertainty in the eutectic composition ( T-soly)

Disproportioning by badmixing ( T-soly)

Disproportioning effects can be like this

Rationale -2Key QA aspects:1. Material certified application database according with the

material design functionalities [see., E. Mas de les Valls et al., JNM ]

2. Certified characterization techniques supporting database3. QA demands to (LLE) characteristics: constitutive and

compositional- QA constitutive specifications: & Li aggregation

- Compositional specifications apply for Li titlecertification & impurity levels

Production and material testing routes should be fixed according to QA standards

In the EU, TBM Consortium of Associates (CIEMAT) is generating a procurement plan for 6LLE according to nuclear standards

Roadmap for Pb - Li eutectic QA procurement

Lack of database reproducibility for key FT properties can not even more potentially be justified in terms of material uncertainties

• Revision of set of ISO norms– ISO3131/- 1, /-5, Light Metals and light alloying metal: methods for

processing and treatment, in force for Nuclear Materials and IAEA Regulations.

• Fixing Material specification in terms of:– maximum allowable impurity contents– Li contents global deviations (ex. < ± 0.2 Li at%) – Homogeneity criteria (ex. maximum size and distribution of Li and other

Li-Pb phases aggregates

• Establishment of a production route (with specification of endorsing ISOs) according to previous material QA criteria.

• Establishment of set of certification tests for Material QA (fine calorimetry at eutectic, x-ray phase study, Atomic Absorptions Technique, …)

Programme goals

• In parallel to EU ITER/DA F4E activities (GRT-030) Spanish TECNO_FUS 2009/2012 Programme (CIEMAT, UCM) is facing production of 6LLE according to ITER QA standards

6LLE FUNCTIONAL (REPRODUCIBLE) DATABASE

CERTIFIED CHARACTERISATION

6LLE PRODUCTION ROUTES

MICROSTRUCTURE HYPEREUTECTIC

INGOTS A 15.8-16.1±0.2%at LiInstitute of Physics of the

University of Latvia (IPUL)

INGOTS B 18.8±4.1–19.4±3.5%at Li "Jost-Hinrich Stachov Metahandel",

Germany

MICROSTRUCTURE NEARLY EUTECTIC

Present EU Pb –Li alloy specs.

Certified characterization

Figure 1: Phase diagram of Pb-Li system

[Tegze and Hafner, 1989]

Y Ref. at.% Li Alloy origin T-control Analysis Uncertainties

88 [5] 16.98 CEA, Li(99.5) and Pb(99.994)

-- -- --

91 [6] 16.55 Alloyed at home Poor detail N.S.

91 [3] 16.98 laboratory, Li(99.4) from Metallgesellschaft with 0.5 Na, 0.01 K, 0.03 Ca,

<0.01 Al, <0.03 Si and Pb(99.99) from Ventron

Thermalanalysis (Ni-

CrNi-thermocouples) and thermal

differential analysis with

a Netzsch DTA

AAS 0.01 wt.%, oxygen

impurities

were below the hot

extraction method (0.01%)

92 [7] 15.7 laboratory, use of an electromagnetic pump to ensure the homogeneity

measurement of electrical

resistance as a function of T

--

05 [10] 15.8 laboratory, use of a three-phase MHD

stirrer. Comparison with a sample from

METEAUX-SPECIAUX (1993) and another from

Jost-Hinrich Stachov Metallhandel (2003)

X-ray phase study,

AAS

1.3 at.%

06 [11] 16.97 laboratory, Li(99.8) and Pb(99.99)

-- 0.20 wt.%

Pb-Li binary diagram

Experimental Procedure

• Material– Ingot A

– Ingot B

Previos work – Temperature distribution

• Ingot A– Homogeneous distribution

• Wall solidification

• Ingot B – Tf >> del ingot A

• High temperature areas238

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Ingot A

243

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227228229230231232233234235236237238239240241242243

Ingot B

Previous work – Chemical analysis

0 2 4 6 8 10

10

20

30

40

50

Lingote A

ThermoX ELAN

6Li

7Li

[Li]A = 18.31 ± 0.50 % at

Composición nominal fabricante

Composición eutéctico Pb - Li

co

nc.

Li

/ %

at

muestra

0 2 4 6 8 10

10

20

30

40

50

Lingote B

ThermoX ELAN

6Li

7Li

[Li]A = 24.04 ± 1.38 % at

Composición nominal fabricante

Composición eutéctico Pb - Li

co

nc.

Li

/ %

at

muestra

Ingot A Ingot B

Previos work –Li elemental analysis

• %at Li (distribution)– A < B

– >> first solidification areas

– >> eutectic

– >> nominal composition

– Dependence with position

– Similar behaviour than T

0 1 2 3 40.0

0.5

1.0

1.5

2.0

Y

X

1415161718192021222324252627282930

Ingot A3

0 1 2 3 40.0

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1.0

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2.0

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X

1415161718192021222324252627282930

0 1 2 3 40.0

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1415161718192021222324252627282930

Ingot A1 Ingot B E

Ingot B int

0 1 2 3 40.0

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1.0

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2.0

Y

X

1415161718192021222324252627282930

Previous Work

Measurement Teut(M)≈237 °C y Teut(S)≈231 ° C – Ingot A shows the highest homogeneity

0 5 10 15 20 25 30220

240

260

280

300

320

ASM (up dated 1993)

Hubberstey et al.; Grube & Klaiber

Czochralski & Rassow; Pogodin & Schtilineshkii

Este trabajo

Lingote A ; Lingote B

Tem

per

atu

ra /

0C

Li / %at

0 5 10 15 20 25 30220

240

260

280

300

320

ASM (up dated 1993)

Hubberstey et al.; Grube & Klaiber

Czochralski & Rassow; Pogodin & Schtilineshkii

Este trabajo

Lingote A: Tfc= ; Tf

e= ; Lingote B: Tf

c= ; Tf

e

Tem

per

atu

ra /

0 C

Li / %at

A: Induction Furnace (8 kW)

B: Reactor (Cr-Ni Alloy)

C: Gases battery

Basic scheme of our melting system

Vacuum

Windows

ThermocoupleGas Innlet

SiC crucible & Pb-Li ingots

Equipment designed

Experimental description

• Material– Pb(s) ultrapure

– Li(s) ultrapure

• Experimental condition– Atmosphere

• N2, Ar, molten salt,...

– Temperature• 350 – 800 °C

– Time?

– Crucible• C, CSi, SiO2

Crucible material selection - Reactivity of the LLE

Experimental setup

Group Ingot Temp (°C) time (min) Gas Crucible

I

PbLi 0 450

15 N2 (T)

C

PbLi 1 550 C

PbLi 2 650 SiC

IIPbLi 4 600 15

ArSiC

PbLi 3 650 30 SiO2

III PbLi 5 700 - 800 5-15 Ar (BIP) SiC

IV

PbLi 10 350 8

Ar (BIP) + eutectic LiCl/KCl

SiCPbLi 8 400 15

PbLi 7 450 15

PbLi 6 700 5

V PbLi 9 400 3Air + eutectic

LiCl/KClSiC

VI PbLi 11 350 8Ar (BIP) + eutectic

LiCl/KClSiC

Group Ingot %at Li

I

PbLi 0 16.6

PbLi 1 17.5

PbLi 2 16.4

IIPbLi 4 17

PbLi 3 15.8

III PbLi 5 17.3

IV

PbLi 10 15.5

PbLi 8 16.6

PbLi 7 13.5

PbLi 6 13.7

V PbLi 9 15.2

VI PbLi 11 31.55

Results - Chemical characterization by ICP-MS

Results - Microstructure & DSC characterization

0 100 200 300 400 500

-0,9

-0,8

-0,7

-0,6

-0,5

-0,4

-0,3

-0,2

-0,1

0,0

0,1

0,2

0,3

0,4

0,5

Eutectic

Eutectic

T (ºC)

Q (

mW

/mg

) Eutectic Pb-Li ingots

Hipoeutectic Pb-Li ingots

Results - Microstructure & DSC characterization

0 100 200 300 400 500

-0,7

-0,6

-0,5

-0,4

-0,3

-0,2

-0,1

0,0

0,1

0,2

0,3

0,4

Solidification

Eutectic

Melt

Eutectic

T (ºC)

Q (

mW

/mg

)

Intermetallic Pb-Li

Hipereutectic Pb-Li ingots

0 100 200 300 400 500

-0,5

-0,4

-0,3

-0,2

-0,1

0,0

0,1

0,2

0,3

Melt

Solidification

Eutectic

Q (

mW

/mg

)

T (ºC)

Eutectic

oxidation

Results - Microstructure & DSC characterization

Li3N and PbO

XRD pattern of the oxidized phases

Results – Melting points

Ongoing efforts

• Impurity control

• Optimization of the melting process

– Impurity control

– Design of the thermal treatment

– Reduce of oxidation process

• Li