Current status of assessment of Tritium inventory in all-W device

© Olga Ogorodnikova, 2008, Salamanka, Spain

Current status of assessment of Tritium inventory in all-W device

O.V. Ogorodnikova and E. d’Agata


Be: port limiter,primary wall, baffle

W: upper vertical targets, dome

CFC: lower vertical targets

Initial plasma-facing materials for ITER divertor


Tungsten

ITER divertorUpper part Inner VT

Upper partOuter VT

Dome

Act as baffles for the neutrals

100 m2


CFC

ITER divertorLower partInner VT

Outer VT

Lower partOuter VT

Interact directly with the scrape-off layer plasma

50 m2


W

ITER divertorLower partInner VT

Outer VT

Lower partOuter VT

Interact directly with the scrape-off layer plasma

50 m2


Vertical Target

W monoblocks(upper andbottom half)

Mario Merola and ITER team


Dome

W flat tiles with HV cooling


- flat tile concept cooled by HV-


First Wall

W

CuCrZr


W macrobrush: W/CuCrZr

Plasma spray W: PSW/CuCrZr


Tritium inventory

Joachim Roth: PSI-18 Toledo, May 26, 2008


Talk outline

- T retention in outer vertical target

- T retention in inner vertical target

- T retention in dome

- T retention in FW

Normal operation regime

Comments to off-normal operation regime


Talk outline

- T retention in outer vertical target

- T retention in inner vertical target

- T retention in dome

- T retention in FW

Normal operation regime


Vertical target at glancing angle of incidence

The particles impinge the surface with a glancing angle of alfa=1-3. It will result in high heat and particle fluxes on the edges


Vertical target at glancing angle of incidence

The particles impinge the surface with a glancing angle of alfa=1-3. It will result in high heat and particle fluxes on the edgesThe asymmetrical heat and particle loads as well as asymmetricalcooling result in inhomogeneous temperature distribution

inhomogeneous temperature distribution => inhomogeneous T retention


Erosion due to off-normal events (?)

plasma

20 shots @ 1.4 MJm-2

I. Arkhipov, A. Zhitlukhin, Troitsk, RF

MK200-U

Performance of W under short transient thermal loads


Influence of off-normal events

plasma

20 shots @ 1.4 MJm-2

I. Arkhipov, A. Zhitlukhin, Troitsk, RF

MK200-U

How much T will be co-deposited (or re-deposited) and where?


Steady state loads at outer vertical target

The total power load consists of about 30% due to irradiation from the plasma and about 70% due to particles heating

-0.2 0.0 0.2 0.4 0.6 0.80

2

4

6

8

10

12

14

particles (70%)

radiation (30%)

total

distance along outer plate, m

Pow

er, M

W/m

2


Correlation of the particle fluxes, plasma temperature and power load on outer divertor target

-0.2 0.0 0.2 0.4 0.6 0.80.02.0x1023

4.0x1023

6.0x1023

8.0x1023

1.0x1024

1.2x1024

1.4x1024

1.6x1024

-0.2 0.0 0.2 0.4 0.6 0.80

2

4

6

8

10

12

-0.2 0.0 0.2 0.4 0.6 0.80

2

4

6

8

10

12

Ele

ctro

n tem

pera

ture

, eV

, or

Heat flu

x, M

W/m

2


ions

neutrals

4 MW/m2

Power

Te



-0.2 0.0 0.2 0.4 0.6 0.80.0

2.0x1023

4.0x1023

6.0x1023

8.0x1023

1.0x1024

-0.2 0.0 0.2 0.4 0.6 0.802468

101214161820

-0.2 0.0 0.2 0.4 0.6 0.802468

101214161820

Ele

ctro

n tem

pera

ture

, eV

, or

Heat flu

x, M

W/m

2


ions

Te

4 MW/m2

Power


Correlation of the particle fluxes, plasma temperature and power load on outer divertor target


An increase of the plasma temperature results in - an increase of the density and power load

-0.2 0.0 0.2 0.4 0.6 0.80.0

2.0x1023

4.0x1023

6.0x1023

8.0x1023

1.0x1024

-0.2 0.0 0.2 0.4 0.6 0.802468

101214161820

-0.2 0.0 0.2 0.4 0.6 0.802468

101214161820

Ele

ctro

n tem

pera

ture

, eV

, or

Heat flu

x, M

W/m

2


ions

Te

6 MW/m2

4 MW/m2Power



-0.2 0.0 0.2 0.4 0.6 0.80.0

2.0x1023

4.0x1023

6.0x1023

8.0x1023

1.0x1024

-0.2 0.0 0.2 0.4 0.6 0.802468

101214161820

-0.2 0.0 0.2 0.4 0.6 0.802468

101214161820

Ele

ctro

n tem

pera

ture

, eV

, or

Heat flu

x, M

W/m

2


Te

ions 4 MW/m2

17 MW/m2

Power


An increase of the plasma temperature results in - an increase of the density and power load

- Shift of a maximum to the strike point


• n-irradiation effect: Wmax=f(dpa, tem)

• He ions implantation simultaneously with D ions: influence on D retention and TDS

Helium ion bombardment leads to development of the surface relief and destruction of near surface layer

• Flux dependence

• Off-normal events and ELM’s should be taking into account

R&D


• Embrittlement: W, as typical for bcc metal, after neutron irradiation embrittled due to irradiation hardening and loss of strength at grain boundaries due to contamination by interstitial impurities.

• Due the high activation of W there is no direct data on the effect of neutron irradiation on tritium retention.

• Voids:For W despite of low swelling, the vacancy voidformation occurs at ~ 400C < Tirr < 1000C anddamage dose more than ~ several dpa.

Typical structure - superlattice of voids:~ 5 - 50 nm diameter and lattice parameter ~ 60 - 200 nm

n-irradiation effect


Voids:For W despite of low swelling, the vacancy voidformation occurs at ~ 400¡C < Tirr < 1000¡C anddamage dose more than ~ several dpa.Typical structure - superlattice of voids:~ 5 - 50 nm dia and lattice parameter ~ 60 - 200 nm

n-irradiation effect

Tungsten for ITER divertor - Tungsten for ITER divertor -damage ~ < 0.1 dpa, T- 200-1000¡C (with replacement)- no changes of physical properties;- no significant changes at transient events (VDE/disr.);- no changes of erosion;- bulk tritium retention seems low (to be confirmed);

Current status of assessment of Tritium inventory in all-W device

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