J. Roth, EU PWI TF, SEWG Fuel Retention, Cadarache, June 15, 09 Tritium inventory: Joint...

J. Roth, EU PWI TF, SEWG Fuel Retention, Cadarache, June 15, 09

Tritium inventory: Joint international scaling for ITER

WP09-PWI-01-01/IPP/PS

• Status by end of 2008

• New data with emphasis on retention in W

- reduced uncertainty and confirmation of saturation

- simultaneous He irradiation

- influence of n-irradiation damage

• Conclusion at ITPA meeting Amsterdam, May 2009

• Further research priorities


Status by end of 2008

all-C

mat

eria

ls

initi

al IT

ER mix

Be wall +

W diverto

r

all-W materials

C ves

sel w

all

Be ve

ssel

wal

l

all-W materials

150W

/mK 15

0W/m

K

50W

/mK

50W

/mK

high flux

low wall flux

Be wal

l with

CFC d

iver

tor

- In a W wall, in saturation, 3·1027 traps available (equivalent to 15 kg of tritium if all filled)- Modelling of trap creation and subsequent filling beyond m range are in progress


Reduced uncertainty and confirmation of saturation

V. Alimov, J. Roth, ITPA 09

• Confirmation of saturation of retention with maximum around 500 K

• New low energy data from UoT narrow the data cloud

J.W. Davis, A.A. Haasz, ITPA 09

1E22 1E23 1E24 1E25 1E26 1E27

1E18

1E19

1E20

1E21

1E22

1E23

IPP Ogorodnikova Toronto Haasz DIONISOS Wright TPE Causey JAEA Alimov, Shu PISCES Doerner FTU Loarte Magnetron Alimov PISCES Wampler PSI2 Loarte TEXTOR Philipps TPE Kolasniski

Re

tain

ed

(D/m

2)

Fluence (D/m2)

poly-W, 500 KD energy 38-200 eVTDS


Influence of n-irradiation damage

Pure WPure WDiffusion up to at least 6 m, low concentration at the surfaceWW W WDeuterium behavior in self-implanted W is like in pure W diffuses up to 6 mHigh D concentration at the surface D fills the radiation defectsCC W WIn the presence of carbon, the deuterium diffusion decreases strongly

B. Tyburska, IBMM Dresden, 2008


Influence of n-irradiation damage

0.000

0.001

0.002

0.003

0 1 2 30.00000

0.00005

0.00010

0.00015

200C

D/W

dpa/500

dpa D/W 0 0.00003 0.008 0.00055 0.08 0.00205

500C

Depth (micron)

12 MeV Si ion irradiation, subsequent D plasma in PISCES (100 eV, 1e26 D/m2)

Number of traps produced from ITER lifetime neutron fluence ~0.005 /W at 200ºC,~0.0001/W at 500ºC.

Observed uptake rate is three orders of magnitude smaller than predicted by frequently used model based on diffusion and surface recombination.

At 200ºC trapped D is limited by slow kinetics, ie. permeation.

Trapping at 40ºC is smaller due to slower kinetics.

Trapping at 500ºC is smaller due to annealing of damage.

Tritium inventory from trapping at neutron damage in tungsten should be small in ITER (8 g at lifetime).

B. Wampler, ITPA Amsterdam 2009


Simultaneous He irradiation

300 400 500 600 700 8001018

1019

1020

1021

1022

D/H

e re

tain

ed (

atom

s/m

2 )

Exposure temperature (K)

Deuterium (NRA & TDS)NRA (0-7 m)TDS

Pure and helium-seeded D plasma W, = 1027 D/m2



300 400 500 600 700 8001018

1019

1020

1021

1022

D/H

e re

tain

ed (

atom

s/m

2 )


Deuterium (NRA & TDS)0% He ions0.2% He ionsNRA (0-7 m)

TDS




300 400 500 600 700 8001018

1019

1020

1021

1022

D/H

e re

tain

ed (

atom

s/m

2 )


Deuterium (NRA & TDS)0% He ions0.2% He ions5% He ions


NRA (0-7 m)TDS



300 400 500 600 700 8001018

1019

1020

1021

1022

D/H

e re

tain

ed (

atom

s/m

2 )


Deuterium (NRA & TDS)0% He ions0.2% He ions5% He ions


NRA (0-7 m)TDS

Helium (TDS)0.2% He ions5% He ions


Conclusion at ITPA meeting Amsterdam

The general conclusion of the session was:

• while several interesting scientific aspects of retention in tungsten are still unresolved and worthy of further investigation, from an ITER viewpoint the retention channel in tungsten is small.

• When tungsten is exposed to mixtures of helium and deuterium this already small amount of retention is further reduced and therefore retention is tungsten is not considered to be a major concern for ITER operation.

• The effect of retention in pre-damaged tungsten was also investigated and the migration of tritium deep into the bulk was estimated from experimental measurements to be small (on the order of a few grams during the lifetime of ITER).

• The only outstanding issues concerning tungsten retention are the effects of transient heat loads and the influence of mixed material surfaces for retention in the underlying bulk tungsten.


Further research priorities

1. Refine ITER prediction (MIT mini-meeting) : High priority Report B. Lipschultz• Participants (JAEA, FZJ, UCSD, IPP, Kyushu, CEA, MIT, UofT, Sandia, ITER, JET, FOM)

2. Fuel retention machine database : High priority DSOL E.Tsitrone• Participants (FZJ, MIT, CEA, IPP, JET)

3. Ion cyclotron wall cleaning : High priority DSOL V. Philipps• Participants (VR, FZJ, MIT, CEA, IPP, JET)

4. Disruption flash heating : Med. priority• Participants (CAE, UCSD, UKAEA, ITER, JET)

5. Capability and risks of removing C : Med. Priority Report J. Davis• Participants (UofT, VR, FZJ, CEA, IPP, JET)

6. Isotope exchange : Med. Priority DSOL T. Loarer• Participants (JAEA, MIT, CEA, IPP, INL, Kyushu, FZJ, JET)

7. T removal by heating to 350C : High priority Report J. Roth• Participants (MIT, CEA, UCSD, IPP, INL, Sandia, UKAEA)

8. Retention in gaps : Med. Priority DSOL K. Krieger• Participants (FZJ, IPP, INL, UKAEA, Kyushu, JET)

9. Influence of mixed species on retention DSOL R. Doerner• Participant (UCSD, IPP, Kyushu, FZJ, JAEA, UofT, JET)

10. Preparation for the JET ILW experiment• Participant (JET TFs, IPP, MEdC, TEKES, UK, SCK-CEN, IST, VR, Estonia, AEV Latvia)

J. Roth, EU PWI TF, SEWG Fuel Retention, Cadarache, June 15, 09 Tritium inventory: Joint...

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