Transcript LiPb specifications and the chemistry control

IEA Implementing Agreement on Nuclear Technology for Fusion Reactors
Liquid Breeder Blankets Subtask
Coordinating Meeting on R&D for Tritium and Safety Issues in Lead-Lithium Breeders
11-12 June 2007, Idaho Falls, ID, USA
LiPb specifications and the chemistry control
O. Gastaldi 1, L. Sedano2,
(1 CEA, 2 CIEMAT)
Association
with Euratom
IEA Tritium and Safety Issues in LL Breeders, 11-12 June 2007, Idaho Falls
O. GASTALDI
What are the main issues ?
Two kinds of problem must be solved in the
field of LLE chemistry control:
– All teams involved in LLB studies must work with the
same PbLi eutectic
specifications of the common eutectic %Li
 specifications of maximum impurities content
– During operation of TBM, the chemistry must be
controlled
Association
with Euratom
IEA Tritium and Safety Issues in LL Breeders, 11-12 June 2007, Idaho Falls
O. GASTALDI
Lead-Lithium Eutectic QA as Nuclear Material
Summary
Li-Pb eutectic (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) … as it
will be demanded for the tons of TBM needs in ITER
QA demands to (LLE) refer to Constitutive and to Compositional
characteristics
QA constitutive specifications apply for accurate Li title and control of
Li structural micro-aggregation
Compositional specifications apply for impurity levels
Some key materials Fusion Technology properties can largely change
through deviations (ex.: Li aggregation or Li in excess in an supposed
eutectic can have a large effect on tritium solubility)
Production and material testing routes should be fixed according to
QA standards
Association
with Euratom
IEA Tritium and Safety Issues in LL Breeders, 11-12 June 2007, Idaho Falls
O. GASTALDI
Compositional specifications apply for impurity levels
Content (ppm)
Element
Ag
<1
Al
1
As
40
Au
<1
Cr
<3
Cu
<1
Cd
<1
Fe
13
Ga
<1
Hg
<1
In
<1
Li
0.68%
Ni
7
P
<10
Pb
Balance
Sb
<10
Su
<5
Ti
<10
Bi
0.02%
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Some impurities typically linked to
Lithium (1 ppm Al) might be used for a
fast homogeneity test
Major interest is of course to minimize
Bi content (below tenths ppb).
IEA Tritium and Safety Issues in LL Breeders, 11-12 June 2007, Idaho Falls
O. GASTALDI
LEAD-LITHIUM EUTECTIC TITTLE
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
Thermal
analysis (NiCrNithermocouples
) 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 threephase MHD stirrer.
Comparison with a
sample from METEAUXSPECIAUX (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.%
Li chemical activity determine LLE activity: title has large impact on NFT.
Tritium solubility in LLE would largely depends on Li-disproportioning by
bad mixing or local aggregation. Other properties less modified
2at% Li deviations are unacceptable from QA of LLE as Nuclear Material
Association
with Euratom
IEA Tritium and Safety Issues in LL Breeders, 11-12 June 2007, Idaho Falls
O. GASTALDI
LEAD-LITHIUM EUTECTIC TITTLE
Uncertainty in the eutectic composition ( T-soly)
- Errors in estimation depend on the
Ks
 (LnK
)  1  (at .Li .  (at .Li ) )
(Ks)
experimental protocol 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, [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 ()
s Pb 17 Li
Li
eut
eut
Disproportioning by bad
mixing ( T-soly)
- not systematically checked & driving
potentially to incorrect overestimated
solubility (in connection with Li-aggregation
by clustering)
- Mixing light Li with heavy Pb and large
homogeneity is not an easy technical mater
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Deviation from theoretical eutectic composition
[15.7(2)at%Li] at liquid phase and solubility
impact with Li aggregation.
Disproportioning effects can be
like this
IEA Tritium and Safety Issues in LL Breeders, 11-12 June 2007, Idaho Falls
O. GASTALDI
The practical situation when homogenity is checked !!!:
It is the J-H Stachow GmB commercial alloy.
Test performed by Freibergs (UPUL, Latvia) 2005
This eutectic has been used for solubility determinations (!!!!)
This eutectic is used in present irradiations LIBRETTO -4 (!!!!)
Association
with Euratom
IEA Tritium and Safety Issues in LL Breeders, 11-12 June 2007, Idaho Falls
O. GASTALDI
Different commercial production
Mixing drawbacks:
 fast alloying rates and very difficult
local temperature control
 possibility of formation of hard
melting Li5Pb2, LiPb, Li3Pb
( Higher Li activity so Tritium
solubility higher than in the eutectic
!!!! )
Li dosage control and MHD stirring
technology seems needed for mixing
Feasibility at semi- industrial scale ?
Association
with Euratom
IEA Tritium and Safety Issues in LL Breeders, 11-12 June 2007, Idaho Falls
O. GASTALDI
Roadmap for Pb-Li eutectic QA guarantees
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: (1) maximum allowable
impurity contents, (2) Li contents global deviations (ex. < ± 0.2
Li at%) and (3) 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, …)
Lack of database reproducibility for key FT properties can not
even more potentially be justified in terms of material
uncertainties
Association
with Euratom
IEA Tritium and Safety Issues in LL Breeders, 11-12 June 2007, Idaho Falls
O. GASTALDI
During operations
What has to be controlled in LLE?
– Control of impurities must be insured:
• In order to guarantee tritium inventory
• In order to allow a good analysis of experimental tests
• In order to avoid precipitations
– Dynamic control of Li content
– Follow-up of tritium concentration
Association
with Euratom
IEA Tritium and Safety Issues in LL Breeders, 11-12 June 2007, Idaho Falls
O. GASTALDI
During operations
What is needed in term of measurement tools:
– For oxygen: Technology is known (electrochemical
probes): validation in real conditions (flow rate mainly,
magnetic field,…) must be checked
– For tritium:
• Specific constraints:
– Small variation of tritium in LiPb at each pass
in the TBM
– Short duration of pulses
• Then dynamic measurement is needed (with good time
response)
Association
with Euratom
IEA Tritium and Safety Issues in LL Breeders, 11-12 June 2007, Idaho Falls
O. GASTALDI
During operations
Measurement tools:
– For tritium:
• Existing tools:
– Use of permeator sensors
– Time response is too slow to insure dynamic
follow-up of tritium content in TBM (need to
reach equilibrium)
• What are the alternative solutions?
Association
with Euratom
IEA Tritium and Safety Issues in LL Breeders, 11-12 June 2007, Idaho Falls
O. GASTALDI
During operations
For impurities control what are the main issues:
– Li title adjustement (mainly for DEMO application) Without doing agregates in order to guarantee
homogeneous mixture
– Cold trap optimisation (mainly for DEMO application)
Association
with Euratom
IEA Tritium and Safety Issues in LL Breeders, 11-12 June 2007, Idaho Falls
O. GASTALDI
Main points to treat
Define a reference specifications for LLE
composition (EU can propose it)
Define a production route with associated QA
Define develop and test tritium measurement
tools (with short time response) efficient in
realistic conditions (dynamic loop)
Association
with Euratom
IEA Tritium and Safety Issues in LL Breeders, 11-12 June 2007, Idaho Falls
O. GASTALDI
Association
with Euratom
IEA Tritium and Safety Issues in LL Breeders, 11-12 June 2007, Idaho Falls
O. GASTALDI
References
[3, Schulz,1986]
[5, Fauvet st Sannier, 1988]
[6, Reiter, 1991]
[7, Hubberstey, 1992]
[10, Freibergs, 2005]
[11, Stankus 2006]
Association
with Euratom
IEA Tritium and Safety Issues in LL Breeders, 11-12 June 2007, Idaho Falls
O. GASTALDI