KIT – Universität des Landes Baden-Württemberg undnationales Forschungszentrum in der Helmholtz-Gemeinschaft www.kit.edu
Pb Alloys Coolant Chemistry and Structural Materials Performance: a Review
Concetta Fazio
Actinide and Fission Product Partitioning and Transmutation11th Information Exchange Meeting
San Francisco, USA1- 4 November 2010
Program Nuclear Saftey Research
Concetta Fazio Program Nuclear Safety Research2 1-4 November 2010
Outline
Pb alloys cooled nuclear system
Coolant chemistry control and Handling: some key issues
Solubility and Diffusivity dataOxygen measurement and adjustmentSolid Impurities Filtering Systems
Key Materials issues and latest results
Summary and outlook
Concetta Fazio Program Nuclear Safety Research3 1-4 November 2010
Pb alloys cooled systems
15 Proton Proton beambeam1515 Proton Proton beambeam
ADS: The EFIT system
LFR: The ELSY system
Spallation Target: MEGAPIE
Concetta Fazio Program Nuclear Safety Research4 1-4 November 2010
Operational conditions and materials selectionXT-ADS (LBE) LFR (Pb)
Core components: mechanical stresses: e.g. Hoop stress on cladding
9Cr F/M Steel
T 300 – 500 °C 400 – 530 °C
dpa Up to 160 Up to 100
flow ~ 2m/s ~ 2m/s
Reactor Vessel
Austenitic Steel
T 300 – 400 °C 400 – 430 °C
dpa < 0.02 < 0.003
flow ~ 1 m/s ~ 0.1 m/s
stress 50-150 MPa 80-150 MPa
Heat exchanger
Austenitic or F/M Steel
T 300 – 400 °C 400 – 480 °C
dpa < 0.02 < 0.03
flow ~ 1 m/s ~ 1 m/s
stress ~100 MPa 125-190 MPa
Spallation target
9Cr F/M Steel
T 240 - 340 °C -
dpa/yr Up to 40 -
flow ~ 3 m/s -
stress ~100 MPa + 40 fatigue cycles/yr -
LFR Pump: T= 480 °C; dpa < 0.03; flow = 10 m/s (on impeller)
Concetta Fazio Program Nuclear Safety Research5 1-4 November 2010
Coolant chemistry and corrosion: a key item
500 600 700 800 900 1000
-500
-450
-400
-350
-300
-250
-200
10-4
10-6
Temperature (°K)
RT
ln p
O2 (
kJ/m
ol)
Bi2O3
PbO
NiO
Fe3O4
/FeO
200 300 400 500 600 700 800
10-28 10-26
PbO in Pb45Bi55
10-10
10-8
10-24
10-22
10-20
10-18
10-16
10-14
pO2
Temperature (°C)
O [wt%] in Pb O [wt%] in Pb45Bi55 from Orlov O [wt%] in Pb45Bi55 our calc.
(bar)
H2OH2
103
102
101
1
10-1
10-2
10-3
10-4
10-5
Oxidation of the steel surface The oxide layer can act as a protection barrier
HLM oxides precipitates (plugging!)
Ellingham Diagram
20 μm
PbBi
ferritelayer
20 μm
PbBi
Oxygen content in LBE < 10-9 wt.% T=400 °C
T91 Trans/interganular dissolutionAISI 316L Leaching of Ni and ferritisation
10000 h
[O2]LBE > 10-8 wt.% and < ΔG(PbO)400 °C < T < 550 °C
AISI 316L
Fe3O4
Fe,Cr spinel
Diffusione zone
T91
Concetta Fazio Program Nuclear Safety Research6 1-4 November 2010
Coolant Chemistry and Handling: key issues
Fundamental data: Solubility and diffusivity of metallic and non metallic elements are needed.
Oxygen measurement: Oxygen sensor’s long-term reliability also in irradiation filed, and calibration
Oxygen control systems: gaseous H2/H2O or solid PbO mass exchange systems
Filtering systems: essential to remove solid impurities from the liquid and gas phase
Concetta Fazio Program Nuclear Safety Research7 1-4 November 2010
Solubility and diffusivity data
Gas inletAr 99.999% (PO2 = 2·10-6)
LBE
Platinum gauze
YSZ
Gas outlet
Platinum WireMo wire
Coulometric Oxygen Pump
miror
Laser beam path
laser
lens
Laser-Induced Breakdown Spectroscopy
Development/adaptation of ad-hoc measurement techniques
Measurement of oxygen solubilityMeasurement of solubility of
metallic elements: e.g. NiCourtesy IQS Courtesy CEA
Concetta Fazio Program Nuclear Safety Research8 1-4 November 2010
Solubility and diffusivity data: results
-0.7-0.6-0.5-0.4-0.3-0.2-0.1
00.10.20.30.40.50.60.7
1.1E-03 1.2E-03 1.3E-03 1.4E-03 1.5E-03 1.6E-03 1.7E-03
Martynov, Ivanov, Proceeding of four technical meeting 1998
Rosenblatt, Wilson, Proceeding of Fall Meeting of the Metallurgical Society of AIME, 1969
1/T (K)
Log
S Ni(w
t %)
L. Martinelli et al, LIBS and ICP AES results, 2009
Ni solubility
Courtesy IQS Courtesy CEA
Concetta Fazio Program Nuclear Safety Research9 1-4 November 2010
Oxygen sensor: R&D on basic componentsSolid electrolyte (YSZ)• Optimization for mechanical strength
(e.g., Al2O3 addition)
Reference electrode assessment• Bi/Bi2O3 increases the risk of electrolyte
cracking• Use of Pt/air reduces the requirements on
mechanical stability of the electrolyte
Second (working) electrode assessment• Application of a protecting sheath around
the electrolyte gives rise to sensor fouling and should be avoided
Signal transmission• Issue to be addresses for application in
pool type reactors C. Schroer, KIT
Concetta Fazio Program Nuclear Safety Research10 1-4 November 2010
Absolute accuracy• Can be ±5 mV (±10% cO)• Correction of thermoelectric
voltages is necessary for achieving this accuracy
In-plant testing• Method to distinguish between
functional and flawed sensors available
Long-term performance• in experimental facilities is
promising with respect to industrial application of electrochemical sensors in Pb alloys
Oxygen sensor performance
Sensor accuracy by setting different oxygen potentials in LBE
Long-term performances of sensors
C. Schroer, KIT
Concetta Fazio Program Nuclear Safety Research11 1-4 November 2010
Avoid PbO formationFormation of protective oxide layers
Need for oxygen control
Concetta Fazio Program Nuclear Safety Research12 1-4 November 2010
Oxygen control technologies: Solid Phase mass exchange
IPPE MX, Martynov, ICONE 17
F. Beauchamp, CEA
AdvantagesNo gas managementNo risks of plugging (oxide formation)Quite easy control by flow rate and temperature
DrawbacksMore complex design for MXpMore maintenance: pellets filling• Personal exposure
Risks of oxide precipitation on pellets• Sluggish kinetic for
dissolutionL. Brissonneau, CEA
Concetta Fazio Program Nuclear Safety Research13 1-4 November 2010
Oxygen control technologies: Gas Phase mass exchange
G. Müller, A. Weisenburger KIT
AdvantagesSame device for O2 control and purification by H2.No intervention on the device in normal operationQuite easy to control automatically
DrawbacksRely on sensors if non equilibrium gases are usedNeed for exchange coefficient if equilibrium gases are usedLarge surface exchangeRisks of oxide formationLarge flow ratesRisk of contamination exposure for operators
Concetta Fazio Program Nuclear Safety Research14 1-4 November 2010
Impurities removal technologies
L. Brissonneau, CEA
Poral
Dynalloy
Pall cartridge
Pressure drop vs. time
Filters have been tested:Maintenance problem have been encounteredFor assessment longer experiments are needed
Concetta Fazio Program Nuclear Safety Research15 1-4 November 2010
Key materials issues for HLM systems
Compatibility with Pb and LBECorrosion / oxidation resistanceEnvironmental assisted degradation of
mechanical properties
Irradiation in a fast neutron and for ADS in a proton/neutron field
High dpa (cladding)High H and He (spallation target)coolant / irradiation synergetic effects
Concetta Fazio Program Nuclear Safety Research16 1-4 November 2010
Corrosion / oxidation resistance
Bulk Material
LBE
Bulk Material
LBE
AISI 316L at 450 °C and low oxygen Courtesy CIEMAT
T91 at 450 °C and low oxygen Courtesy CIEMAT
AISI 316L at 550 °C and 10-6 wt.% oxygen (left low exposure time; right high exposure time) Courtesy KIT
T91 at 550 °C and 10-6 wt.% oxygen (left low exposure time; right high exposure time) Courtesy KIT
Concetta Fazio Program Nuclear Safety Research17 1-4 November 2010
Mechanical behaviour in HLM
Creep-ruture test T91. Impact on LCF, fracture toughness and tensilehave been observed as well
LCF test AISI316L. Tensile and fracture toughness test have shown as well no effect
Concetta Fazio Program Nuclear Safety Research18 1-4 November 2010
Summary T91 and AISI316LT T91 AISI 316L
Low (< ~ 400 °C)
• Irradiation H & E• Corrosion low • Impact on mechanical properties
if wetting and stress above certain values
• Irradiation H• Corrosion low • No Impact on mechanical
properties
Medium (≤ ~ 450 °C)
• Slight Irradiation H & E• Oxygen control stringent• Impact on mechanical properties
(see low T)
• No Irradiation H & E• Oxygen control stringent• No Impact on mechanical
properties
High (> 450 °C)
• No irradiation H & E• Oxygen control very stringent
(oxide layer thickness)• Impact on mechanical prop if
oxide layer fails
• No irradiation H & E (high dose swelling)
• Dissolution attack T> 500°C
• No impact on mechanical properties
In the high temperature range for both material corrosion protection would be mandatory
Concetta Fazio Program Nuclear Safety Research19 1-4 November 2010
GESA for corrosion protection
Magnetic-coil Anode
GESA facilitycathode
Volumetric Heating
Melt layer
Surface alloyed layer
e--beam
LPPS sprayed FeCrAl layer
subs
trate
Tests on GESA
Results
Corrosion resistance
Erosion resistance
LCF No reductionCreep-to-rupture
No reduction
LISOR No corrosionHardening
600°C
1 m/s 1,8 m/s
3 m/s
Concetta Fazio Program Nuclear Safety Research20 1-4 November 2010
Summary and outlook
HLM Chemistry and quality controlBasic phenomena have been understoodTechnologies have been tested on laboratory scale and in loop systemsSelection of best performing technology for large scale and pool type is neededTesting of these technologies in large scale pool type is needed
Materials in HLMBasic corrosion mechanism have been understoodBasic mechanical properties degradation mechanism have been understoodPositive impact of corrosion-protection barrier (e.g. GESA) has been assessed.Materials operational window have been identifiedStrategies on materials performance assessment for component lifetime estimation have to be defined
Concetta Fazio Program Nuclear Safety Research21 1-4 November 2010
Acknowledgments: DEMETRA Partners
KIT GermanyAAA France
Ansaldo ItalyCEA France
CIEMAT Spain CNRS FranceCRS4 ItalyENEA Italy
ENEN: IQS KTH
RUB-LEE UCL
SpainSweden
Germany Belgium
FZR GermanyNRG NetherlandNRI Czech RepublicPSI Switzerland
SCK-CEN Belgium
Concetta Fazio Program Nuclear Safety Research24 1-4 November 2010
Ni sheet
Oxygen sensor
zoom
Laser-Induced Breakdown Spectroscopy: principle
Concetta Fazio Program Nuclear Safety Research25 1-4 November 2010
Example of practical application: importance of oxide thickness
(D. Struwe, W. Pfrang, IRS/FZK)
Increase of clad temperature
Shift of the maximum temperature
Axial profiles of clad inner temperature modified calculation with different additional oxide layers
Oxide layer thickness should be limited to < 20-30 μm 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
Concetta Fazio Program Nuclear Safety Research26 1-4 November 2010
0.0 0.2 0.4 0.6 0.8 1.0
3500
4000
4500
5000
5500
6000
6500
7000
7500
8000
steady state 0.1 sec trip 0.5 sec trip 2.0 sec trip 10. sec tripG
AP C
ON
DU
CTA
NC
E (W
/M**
2-K
)
core height
Mechanical properties of materials: Fast Closure of gap between fuel and clad due to beam trips could lead to enhanced stress on the clad. Thermal-shock could affect the oxide integrity
Example of practical application: Importance of mechanical features
δ