mass transfer modeling for lm blankets presented by sergey smolentsev (ucla) with contribution from:...

Mass transfer modeling for LM blankets

Presented by Sergey Smolentsev (UCLA)

with contribution from:B. Pint (ORNL)R. Munipalli, M. Pattison, P. Huang (HyPerComp)M. Abdou, S. Saedi, H. Zhang A. Ying, N. Morley, K. Messadek (UCLA)S. Malang (Consultant, Germany)R. Moreau (SIMAP, France) A. Shishko (Institute of Physics, Latvia)

Fusion Nuclear Science and Technology Annual MeetingAugust 2-4, 2010

UCLA

In this presentation:

• Status of R&D on development of MHD/Heat & Mass Transfer models and computational tools for liquid metal blanket applications

• Examples: corrosion & T transport

OTHER RELATED PRESENTATIONS at THIS MEETINGTITLE Presenter Oral/Poster

Tritium Transport Simulations in LM Blankets

H. Zhang

UCLA

oral

Modeling Liquid Metal Corrosion S. Saedi

UCLA

poster

Integrated Modeling of Mass Transport Phenomena in Fusion Relevant Flows

R. Munipalli

HyPerComp

poster

Mass transfer in the LM flows is one of the key phenomena affecting blanket performance and safety

Traditionally, major considerations associated with the LM flows are the

MHD effects. But there are more….

Tritium permeation is an issue –

no solution has ever been proven

Corrosion/deposition severely limits

the interfacial temperature and thus represents an obstacle to developing attractive blankets at high temperature operation

Blanket: “Hot” leg. Mass transfer coupled with MHD. Corrosion. T production. T leakage into cooling He. Formation of He bubbles in PbLi and trapping T. Ancillary system: “Cold” leg. Turbulent flows. Wall deposition and bulk precipitation. T leakage into environment. T extraction. Cleaning up.

Main objectives of mass transfer modeling

Blanket:• Revisit maximum PbLi/Fe t (470 ?)

and wall thinning (20 m/year ?)• Estimate T leakage into cooling He

streams in the blanket

Ancillary system:• Estimate T leakage into environment• Model T extraction processes• Model clogging/deposition• Model clean up processes

Phenomena, design:• Address “new” phenomena (i.e. He

bubble formation in PbLi and trapping T by the bubbles)

• Find new design solutions/modifications

Challenge!

The whole PbLi loop, including the blanket itself and the ancillary equipment, must be modeled as one integrated system

What do we need?

• New phenomenological models for: - interfacial phenomena - nucleation/crystallization - particle-particle/wall interaction - MHD effects on mass transfer - T transport physics

• New material databases (He-T-PbLi)

• New mass transfer solvers and their coupling with existing MHD/Heat Transfer codes

He bubble transport and trapping Tby the bubbles is not well understood

What tools do we use?

• HIMAG as a basic MHD/Heat Transfer solver

• Many UCLA research MHD, Heat & Mass transfer codes

• CATRIS (in progress) as a basic mass transfer solver

• Many thermohydraulic / mass transport codes

The R&D on the development of newphenomenological models and theirintegration into numerical codes is underway

CATRIS: MATHEMATICAL MODELS

1. Dilution approximation, Ci<Ci0

2. Lagrangian particle tracking, Ci>Ci0

3. Multi-fluid model, Ci>>Ci0

1

Kp

p kk

dVdt

V

F

( ) ( )ii i i i

CC D C q

t

V

1

Ni

i i ijj

Jt

V1

Nk k k ki i

i i i i i ijj

Vt

VV σ g P

MODELING EXAMPLES

Example Description Modeling status#1

Riga experiment

Modeling of “corrosion” experiment in Riga, Latvia on corrosion of EUROFER samples in the flowing PbLi at 550 in a strong magnetic field

Good match with experimental data on mass loss. Addressing groove patterns needs more sophisticated modeling.

#2

Tritium transport

Numerical analysis of tritium transport in the poloidal flows of the DCLL blanket with SiC FCI under DEMO blanket conditions

Analysis for the front duct of the DCLL DEMO OB blanket has been done using a fully developed flow model.

#3

Magnetic trap

Modeling of extraction of ferrous material suspended in the flowing liquid in a magnetic trap

First “demo” results have been obtained using Lagrangian particle tracking model under some assumptions for B~ 0.1 T.

#4

Sannier equation

Modeling of corrosion of ferritic/martensitic steels in turbulent PbLi flows to reproduce existing experimental data and to address the effect of a magnetic field

In progress. Computations are performed using the UCLA corrosion code (Smolentsev). Turbulence in a magnetic field is modeled via “k-eps” model.

Riga experiment 1/11: setup

Simulation of “CORROSION” EXPERIMENT in Riga

PbLi loop

EUROFER samples

B=0, B=1.7 T

T=550C

U=2.5 cm/s, U=5 cm/s

Time=2000 hours

Rectangular duct, 2.7x1 cm2

Two 12-cm sections of 10 samples in a row, one section at B=0 and one at B=1.7 T

Courtesy of Dr. Andrej Shishko, Institute of Physics, Latvia

Riga experiment 2/11: results

Macrostructure of the washed samples on the Hartmann wall in 3000 hrs at 550

B=0 B=1.7 TUo=2.5 cm/s Uo=5 cm/s

# B=0,T B=1.7,T B=0,T B=1.7,T

1 376 593 437 743

2 245 564 338 757

3 303 481 330 623

4 193 486 283 605

5 223 456 251 506

6 257 440 - -

7 163 483 248 482

8 198 484 310 512

9 214 566 321 463

10 205 502 314 474

Mass loss, mg

Mass loss is almost doubledin the presence of B-field

PbLi flow

Courtesy of Dr. Andrej Shishko, Institute of Physics, Latvia

Riga experiment 3/11: results

• In addition to wall thinning, periodic grooves aligned with the flow direction have been observed on the Hartmann wall

• Mechanism of groove formation is still not well understood

• A. Shishko (Latvia): higher velocity in the surface cavities causes higher corrosion rate. The effect may be related to specimen machining

• R. Moreau (France): the grooves are due to

instability mechanism associated with induced electric currents crossing the interface

Courtesy of Prof. Rene Moreau (SIMAP, France)

•Wall thinning: 1.5->1.4 mm

•Grooves: 40 m deep

~ 500m

~40m

FLOW

Ma

gn

etic fie

ld

Riga experiment 4/11: mathematical model

Basic assumptions

• Fully developed, laminar flow• Only Fe is considered• Purely dissolution mechanism• No oxygen passivation layer• Mass transfer controlled

corrosion• Zero Fe concentration at x=0

2 20

2 20

10

BU U B dP

z y z dx

2 2

0 02 20

B B UB

z y z

2 2 2

2 2 2( )

C C C CU D

x x y z

1 1: 0, 0

1 1: 0, 0

w w

w w

B Bz b U

z t

B By a U

y t

0 0

0 0

0 : 0

: ( ) 0

: ( ) 0

x C

Cz b D K C C or C C

zC

y a D K C C or C Cy

Two BC types have been

tested(C0 is the saturation concentration at given t)

Riga experiment 5/11: material properties*

• Diffusion coefficient Fe-PbLi:

6.4E-09 m2/s**

• Saturation conc. C0: 6.26 g/m3 ***

• PbLi viscosity: 1.08E-07 m2/s• PbLi density: 9300 kg/m3

• PbLi electrical conductivity: 0.7E+06 S/m

• Ha=0 and 227.3 (1.7 T); Cw=0.78; Re=1157 and 2314

* At 550C** Based on equation of Sutherland-Einstein***Recommended by Riga people (=0.676 wppm).

600 650 700 750 800 850T, K

1E-005

0.0001

0.001

0.01

0.1

1

10

100

C0,

wpp

m

Solubility experim entsBarker e t a l., 1988Borgstedt et a l., 1991G rjaznov et a l., 1989R iga group, 2006

Co: more than THREE order of magnitude difference ???

Solubility of Fe in PbLi

Riga experiment 6/11: modeling results

B=1.7 T, Cw=0.78, U=2.5 cm/s

B=0, U=2.5 cm/s

-0 .005 -0.003 -0.001 0.001 0.003 0.005Z , m

0

0.01

0.02

0.03

0.04

0.05

Vel

ocity

, m

/s

B=0, U =2.5 cm /s

B=1.7 T , U =2.5 cm /s


0:BC C C

Riga group: C0=6.26 g/m3, K=4.27E-05 m/s

0: ( ) 0C

BC D K C Cn

Grjaznov et al: C0=3.25 g/m3

MASS LOSS: comparison with the experiment

430

215

Mas

s lo

ss,

m/y

ear

Konys: 700 m/year500C, 0.22 m/s, 0T


0: ( ) 0C

BC D K C Cn


Effect of the velocity and B-field on the wall and bulk concentration


Effect of the velocity- no magnetic field- Hartmann wall

Wall effect- with magnetic field

Effect of B-field-Hartmann wall


Wall concentration

Bulk concentration

0: ( ) 0C

BC D K C Cn


Development length > 10 m (B=1.7 T, U=5 cm/s)

Riga experiment 11/11: conclusions

• Riga experiment on EUROFER-PbLi corrosion has been successfully modeled (not including grooves)

• Higher corrosion rate of EUROFER samples in a presence of a magnetic field can be explained by the steep velocity gradient in the Hartmann layer

• Boundary condition at the solid-liquid interface is still an open issue. Saturation concentration at the wall can be used as a first approximation

• Uncertainty in experimental data on transport properties (e.g. saturation concentration) severely limits modeling predictions

• If to extrapolate to LM blanket conditions - the mass transfer development length can be more than 10 m

Tritium transport, 1/6

• DCLL DEMO blanket conditions (outboard)

• Poloidal flow in a front duct with a 5-mm SiC/SiC FCI

• HIMAG is used to simulate MHD flow, assuming fully developed flow conditions

• CATRIS is used to simulate tritium transport in the multi-material domain, including PbLi flow, SiC FCI and Fe wall

• Goals: (1) T permeation into He; (2) sensitivity study

z

x

yB

Inflow

Outflow

FCI

2.0

m

2.26

m

0.3 m

DCLL Geometry (not to scale)

207 mm

RAFS wall 5 mm thick

SiC wall 5 mm thick

231 mm

z

y

2 mm gap

211 mm

•Neutron wall loading (peak): 3.08 MW/m2

•Surface heating: 0.55 MW/m2

•PbLi Tin/Tout: 500/700C•Flow velocity: 6.5 cm/s•Magnetic field: 4 T•Inlet T concentration: 0•T generation profile: 4.9E-09 Exp(-3y), kg/m3-s


Pb17Li RAFS SiC FCI

Solubilitymol/m3/Pa0.5

[1,2,3]

Dm2/s


[4]

Dm2/s


Dm2/s

[5,6]

σS/m

LowHigh

0.00050.1

1.0 ×10-9

7.0 ×10-9

0.0025 1.5×10-8 0.117 5.0×10-16 5500

Physical properties

1. Mas de les Valls, E., Sedano, L.A., Batet, L., Ricapito, I., Aiello, A., Gastaldi, O., Gabriel, F. (2008) Lead-lithium eutectic material database for nuclear fusion technology. J. Nuc. Mat. 376, 353-357.

2. Reiter, F. (1991) Solubility and diffusivity of hydrogen isotopes in liquid Pb-Li. Fusion Eng. and Design. 14, 207-211.3. Aiello, A., Ciampichetti, A., Benamati, G. (2006) Determination of hydrogen solubility in lead lithium using sole device.

Fusion Eng. and Design. 81, 639-644.4. Aiello, A., Ciampichetti, A., Benamati, G. (2003) Hydrogen permeability and embrittlement in Eurofer 97 martensitic

steel. ENEA Report SM-A-R-001. 5. Causey, R.A., Wampler, W.R. (1995) The use of silicon carbide as a tritium permeation barrier. J. Nuc. Mat. 220-222,

823-826.6. Causey, R.A., Karnesky, R.A., San Marchi, C. (2009) Tritium barriers and tritium diffusion in fusion reactors.

http://arc.nucapt.northwestern.edu/refbase/files/Causey-2009_10704.pdf

There is a considerable degree of uncertainty in the physical properties,particularly for the solubility of T. That is why sensitivity study is needed.

http://arc.nucapt.northwestern.edu/refbase/files/Causey-2009_10704.pdf


Side-wall jets in the bulk

Side-wall gap flowsHartmann-wall

gap flows

The electrical conductivity of FCI may have a strong effect on the T transport via changes in the velocity, especially in the 2-mm gap

=100 S/m, Ha=15,900

Tritium transport, 4/6T concentration (10-6 kg/m3) for cases with low (0.001 mol/m3/Pa0.5)and high (0.05 mol/m3/Pa0.5) solubility of T in PbLi

X=0.5 m

X=1.5 m

Low solubility High solubilityX=0.5 m

X=1.5 mMagnetic

field


Fluxes of tritium through the steel. S= 0.001 mol/m3/Pa0.5, units are 10-9 kg/m2/s

More T permeation occurs from theHartmann gap, where velocity is low

# D S σ T leak

10-9 m2s-1 mol m-3Pa-1/2 Ω-1m-1 %

1 1 0.01 5 1.30

2 2.54 0.01 5 1.40

3 7 0.01 5 1.35

4 2.54 0.0005 5 2.08

5 2.54 0.001 5 1.99

6 2.54 0.005 5 1.65

7 2.54 0.05 5 0.60

8 2.54 0.1 5 0.35

9 2.54 0.01 50 0.36

10 2.54 0.01 500 0.06

Total tritium loss in the front duct

Total T leakage < 2%


• Due to very low diffusion coefficient of T in SiC, FCI can be considered as a T permeation barrier

• All tritium generated in the bulk flow remains there. Tritium permeation occurs mostly from the gaps, especially from the Hartmann gap, where velocity is very low

• Electrical conductivity of the FCI has indirect effect on T transport via changes in the velocity profile: higher - smaller leakage

• Total T leakage into He can be estimated as 2% of all tritium generated in the blanket (not taking into account pressure equalization openings and 3D flow effects)

• More accurate databases for physical properties are needed

mass transfer modeling for lm blankets presented by sergey smolentsev (ucla) with contribution from:...

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