Integrated Modeling of MHD

Flows, Corrosion/Deposition

and Tritium Transport in

Liquid-Metal Blankets

Sergey Smolentsev (UCLA) and the US MHD/Thermofluid Team

International Workshop on LM Breeder Blankets

Sept. 23-24, 2010

CIEMAT, Madrid (Spain)

OBJECTIVES

• Update on development of integrated modeling tools for MHD flows, Heat & Mass transfer (corrosion, deposition, T transport)

• Show modeling examples (MHD mixed convection, MHD corrosion, T permeation)

• Update on construction of a new PbLi loop at UCLA

• Suggest for cooperation in particular areas

Examples of ongoing collaboration

• R. Moreau (Laboratoire SIMAP, France): MHD flows in a fringing field, MHD turbulence, MHD buoyant flows, LM corrosion

• L. Bühler, C. Mistrangelo (Forschungszentrum Karlsruhe, Germany): MHD code validation/comparison, identification of key MHD phenomena for LM blankets

• S. Cuevas (Centro de Invest. in Energia, Mexico): vortical MHD flows, computational MHD

• A. Shishko (Institute of physics, Latvia): LM corrosion

• Z. Xu (SWIP, China): MHD flow in a duct with FCI

• J-US TITAN 1-3: MHD flows for LM blanket applications

MHD/Thermofluid considerations for S-C, DCLL, HCLL

MHD related issue / phenomena S-C DCLL HCLL

1. MHD pressure drop *** ** **

2. Electrical insulation *** ** *

3. Flow in a fringing magnetic field *** *** **

4. Buoyant flows ** *** ***

5. MHD instabilities and turbulence *** *** *

6. Complex geometry flow and flow balancing *** *** ***

7. Electromagnetic coupling *** ** ***

8. Thermal insulation * *** *

9. Interfacial phenomena *** *** *

*- not applicable or low importance; ** - important; *** - very important

S-C – self-cooled, DCLL – dual-coolant lead-lithium, HCLL – helium-cooled lead-lithium

S. SMOLENTSEV, R. MOREAU L. BÜHLER, C. MISTRANGELO, “MHD Thermofluid

Issues of Liquid Metal Blankets: Phenomena and Advances,” ISFNT 9, 2009.

MHD effects are, traditionally, the major considerations

for LM flows. But there are more…

Ancillary system - “Cold” leg

Deposition

T leakage into environment

T extraction

Cleaning up

Blanket - “Hot” leg

Corrosion

T production and transport

T permeation

Formation of He bubbles

Trapping T by He bubbles

Coupling between various physical processes in the blanket and within the

ancillary system requires I N T E G R A T E D M O D E L I N G !

MH

D flo

wH

D tu

rbu

len

t flow

Development of integrated modeling tools

• • Continuing to develop HIMAG as a basic MHD/Heat Transfer solver –code acceleration is the major objective. Recent implementation of “wall functions” allows for code acceleration by factor 5-20 !

• CATRIS is a new mass transfer solver coupled with HIMAG – just started. Various models from “dilution approximation” to “multi-fluid models”

• New PHENOMENOLOGICAL MODELS for tritium transport, interfacial phenomena and corrosion/ deposition need to be developed – in progress

CATRIS: MATHEMATICAL MODELS

1. Dilution approximation, Ci<Ci0

2. Lagrangian particle tracking, Ci>Ci0

3. Multi-fluid model, Ci>>Ci0

1

Kp

p k

k

dV

dt

V

F

( ) ( )ii i i i

CC D C q

t

V

1

Ni

i i ij

j

Jt

V

1

Nk k k ki i

i i i i i ij

j

Vt

VV σ g P

Mixed Convection – MHD equations and energy

equation are solved simultaneously

• Strong Archimedes forces in PbLi,

cause buoyant flows

• Forced flow ~ 10 cm/s

Buoyant flow ~ 30 cm/s

• Affects the temperature field in the solid,

interfacial temperature, heat losses and

tritium transport – all IMPORTANT!

Rapidly decaying volumetric heating

results in pronounced radial temperature

gradients in the PbLi

Our goal is to model buoyant flows in a DCLL blanket for ITER and DEMO

0

5

10

15

20

0 5 10 15 20 25 30 35 40

FSLiPbSiC

Po

wer

Den

sity

(W

/cm

3)

Radial Distance from FW (cm)

Radial Distribution of Power Density in DCLL TBM Components

Neutron Wall Loading 0.78 MW/m2

LL

SiC FS

PbLi

Ferritic steel

Mixed convection: 3D modeling

Reduction of 3D effects and tendency to quasi-two-dimensional state

as Ha number is increased have been observed

Ha=100 Ha=400 Ha=700 Ha=1000

g g g

Re=10,000

Gr=107

a/b=1

Mixed convection: downward flow

Ha = 400; Re = 10,000, Gr = 1e+07 Ha = 1000; Re = 10,000, Gr = 1e+08

Hot spot !

g

Mixed convection: 1D versus 3D

Ha=400 Ha=700 Ha=1000

Fu

lly d

evelo

ped

1D analytical solution

-Flow is Q2D

-Flow is fully developed

Major assumptions of the 1D theory

have been verified with 3D modeling.

1D vs. 3D comparison is fair

Full solution Wall functions BC Wall functions BC

MODELING corrosion experiment in Riga

2 2

0

2 2

0

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

z

Cy a D K C C or C C

y

Two BC types have been tested(C0 is the saturation concentration at given t)

• PbLi loop

• EUROFER

• B=0, B=1.7 T

• T=550C

• U=2.5; 5 cm/s

• Time=2000 hours

• 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

Bucenieks I., Krishbergs R., Platacis E., Lipsbergs G., Shishko A.,

Zik A. and Muktepavela F., Investigation of corrosion phenomena in

Eurofer steel in Pb-17Li stationary flow exposed to a magnetic field,

Magnetohydrodynamics, 42, N° 2-3, pp. 237-251, 2006

Riga experiment : modeling vs. experiment

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

Mass loss,

m/y

ear

Tritium transport in poloidal flows

• 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

2.2

6 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

Tritium transport: results

# 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

(sensitivity study)

Total T leakage < 2%

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

• Tritium permeation occurs mostly from the gaps, especially from the Hartmann gap

• Electrical conductivity of the FCI has indirect effect on T transport via changes in the velocity profile

• Total T leakage into He can be estimated as 2% of all tritium generated in the same duct

Experiments with simulants (Hg)

UCLA MHD facilities Magnetic field up to 1.7 T

Manifold experiment: to

address flow distribution in

a complex 3D geometry,

where the LM flow from the

inlet splits into 3 poloidal

channels – tendency to

more uniform flow in a

strong magnetic field

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=421

Re

r, R

ec,

Re

l

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=547

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=687

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=827

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=960

Re

r, R

ec,

Re

l

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=1097

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=1218

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=1358

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=1503

Re

r, R

ec,

Re

l

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=1639

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=1770

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=1894

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=2032

Re

r, R

ec,

Re

l

Re

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=2170

Re

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=2290

Re

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=2429

Re

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=421

Re

r, R

ec,

Re

l

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=547

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=687

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=827

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=960

Re

r, R

ec,

Re

l

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=1097

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=1218

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=1358

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=1503

Re

r, R

ec,

Re

l

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=1639

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=1770

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=1894

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=2032

Re

r, R

ec,

Re

l

Re

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=2170

Re

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=2290

Re

0 5 10 15

x 104

0

2

4

6x 10

4 Ha=2429

Re

Prequalification

experiment: to test new

MHD flow diagnostics

and to address 3D->2D

transitions in duct flows

in a strong magnetic

field

Mixed convection

experiment:

the magnet will be turned

vertically to study buoyant

MHD flows in poloidal-like

channels

New MHD PbLi loop is under construction

at UCLA – completion in 2011

Max. magnetic field ~ 1.7 T

Space inside the magnet ~ 1 x 0.2 x 0.2 m

Temperature ~350-400C

Max. pumping capacity ~ 0.5 L/s, 0.15 MPa

Upgrade in 2011/2012 to increase

pumping capacity (1 L/s, 0.3 MPa),

and operating temperature (500C)

MHD / Heat Transfer

Corrosion/Deposition

Material testing

CONCLUDING REMARKS

• Development of computational tools to model integrated MHD, Heat & Mass Transfer processes in LM blankets and ancillary systems is in progress

• New MHD PbLi facility is constructed at UCLA with completion in 2011 and major upgrades in 2012

• We look for cooperation:

- Phenomenological models (corrosion, deposition,

T transport, He bubble formation, T trapping in He)

- MHD/Heat&Mass transfer code development and

validation

- Experiments in PbLi (MHD, Heat & Mass Transfer,

material testing)