Hydrogen and Helium Recycling at Plasma Facing Materials

236 Pages·2002·11.591 MB·English

by  Rion A. Causey, Tom J. Venhaus (auth.), Ahmed Hassanein (eds.)

Hydrogen and Helium Recycling at
Plasma Facing Materials
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SeriesII: Mathematics,PhysicsandChemistry- Vol. 54
Hydrogen and Helium Recycling at
Plasma Facing Materials
edited by
Ahmed Hassanein
Argonne National Laboratory,
Argonne, Illinois, U.S.A.
Springer-Science+Business Media, B.V.
Proceedings of the NATO Advanced Research Workshop on
Hydrogen Isotope Recycling at Plasma Facing Materials in Fusion Reactors
Argonne, Illinois, U.S.A.
22-24 August 2001
A C.1. P. Catalogue record for this book is available from the Library of Congress.
ISBN 978-1-4020-0512-1 ISBN 978-94-010-0444-2 (eBook)
DOI 10.1007/978-94-010-0444-2
Printed on acid-free paper
AII Rights Reserved
© 2002Springer Science+Business Media Dordrecht
Originally published by Kluwer Academic Publishers in 2002
Softcover reprint of the hardcover 1s t edition 2002
No part of this work may be reproduced, stored in a retrieval system, or transmitted
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CONTENTS
Preface IX
HydrogenRecycling Studiesin Tokamaks and OtherFacilities
1. Hydrogen Isotopes Retention inFusion Reactor Plasma-facingMaterials:
AnAbbreviated Review
R.A.Causey,T.J.Venhaus
2. Trapping Effect inHydrogen Retention inMetals 7
O.V.Ogorodnikova
3. RecentProgress inTritium Codeposition Modeling 17
J.N.Brooks
4. The Effect ofDeuteriumIon Bombardmentonthe Optical Properties 27
ofBeryllium Mirrors
L.A.Jacobson,A.V.Babun,V.N.Bondarenko,G.Konovalov,
1.1. Papirov,LV.Ryzhkov, A.N.Shapoval,A.F.Shtan',
SI.Solodovchenko,A.A.Vasil'ev,V.S.Voitsenya,
A.F.Bardamid,A.I.Belyayeva,A.A. Galuza
5. HotLinerDivertorConcept 35
Analysis ofDustFormationandLocations
V.M.Kozhevin
HydrogenSputtering,Retention,Codeposition in Graphite
6. Hydrogen Isotope Retention Analysis for 47
Tokamak Plasma-facingMaterials
T.A.Burtseva
7. SurfaceMicroreliefInfluence onHydrogen InteractionwithMaterials 57
A.V.Golubeva, A.A.Evanov,N.N.Koborov,V.A.Kurnaev,
S.S.Levchuk,andN.N.Trifonov
vi
Hydrogen RecyclinginLiquid Metals
8. Deuterium Treatment Effects onLithium andTiN-LithiumSputtering 73
inSolid andLiquidPhase
J.P.Allain,D.N.Ruzic
9. Helium Entrapment inLiquidMetalPlasma-facing Surfaces 83
inTokamakFusion Reactors
A Hassanein
FundamentalPermeationStudiesI
10. AModel fortheSteadyStatePlasma- andGas-driven 95
HydrogenIsotopePermeationthroughMulti-layerMetal
O.V.Ogorodnikova
11. EffectofHydrogen Sorption onSurfaceMorphology 105
ofPyrolyticGraphite .
E.A Denisov, T.N.Kompaniets, LV.Makarenko,
Z.Waqar, A.N.Titkov
FundamentalPermeationStudies II
12. General Model ofHydrogen Transport through SolidMembranes 115
K.Habib,A Habib
13. Influence ofHydrogen andHelium onRadiationDamage 125
ofStructural Materials
B.A.Kalin, AN.Kalashnikov,AG. Zaluzhnyi, I.I. Chernov
Hydrogen Recyclingin Tungsten,Niobium,and Nickel
14. DeuteriumRetention inTungsten andTungsten Carbides 131
IrradiatedwithDIons
V.Kh.Alimov, A.P. Zakharov, R.Kh.Zalavutdinov
15. An Interpretation ofthe Retention ofLow Energy Deuterium Ions 145
inTungsten
R.G.Macaulay-Newcombe,A.A.Haasz,M.Poon, J.W.Davis
vii
General HydrogenandHelium Issues andOther Metals
16. HydrogenInteractionwith TiN Films 157
E.A.Denisov,I.E. Gabis, T.N.Kompaniets,
A.A.Kurdyumov,A.A.Yukhimchuk
17. BimetallicDiffusionMembranes: 163
PossibleUse for Active HydrogenRecyclingControl
G.P. G1azunov,E.D.Volkov,A.Hassanein
18. Surface EvolutionofNickel under He and HIon Irradiation 177
by means ofKelvinProbe
G.-N.Luo, K.Yamaguchi,T.Terai, M.Yamawaki
MeasurementsandControl ofHydrogen RecyclingI
19. Developmentofan InnovativeCarbon-basedCeramicMaterial; 189
ApplicationinHighTemperature,Neutronand HydrogenEnvironment
C.H.Wu
20. NonmonotoneTemperatureDependence ofPlasmaDrivenPermeation 199
throughNb Membrane
A.Spitsyn,A. Skovoroda,V.Svishchov,
Yu. Pustovoit,V.Stolyarov
MeasurementsandControlofHydrogen RecyclingII
21. Usage ofHydrogen-saturatedGetterfor SputteringProtection 205
ofConstructionElements inVacuum-plasmaInstallations
V.V.Bobkov,V.N.Borisko,V.V.Chebotarev,LYe.Garkusha,
G.P.G1azunov,Ye.V.Klochko, M.V.Lototsky,N.S.Poltavtsev,
Yu.F.Shmal'ko, R.LStarovoitov,V.LTereshin
22. Laser InducedBreakdownSpectroscopyTechnique 213
for In-situDust DetectinginaNext-stepTokamak
V.M.Kozhevin, E.E.Mukhin, G.T.Razdobarin,
v.v.
Semenov, S.Yu.Tolstyakov,G.Federici
Authors 227
Preface
HYDROGENISOTOPERECYCLING AT PLASMA-FACINGMATERIALS IN
FUSION REACTORS
The Tenth International NATO Advanced Research Workshop on "Hydrogen Isotope
Recycling at Plasma-Facing Materials in Fusion Reactors" is being held at Argonne
National Laboratory in Argonne, Illinois, USA, on August 22-24, 2001, USA. The
General Chairperson for the workshop is Ahmed Hassanein of Argonne National
Laboratory. The local organizer is The Energy Technology Division of Argonne
National Laboratory,Argonne,IL,USA.
TheWorkshopprogram covers the followingtopics:
• Recycling ofHydrogen Isotopes
• WallFuelingand WallPumping
• Active Control ofHydrogen Recycling
Hydrogen andHelium BehaviorinSolidsandLiquidMetals
Databases forRecycling
The workshop wasfirst originated byscientist oftheUniversity ofToyko,Japan andof
theBonch-BruyevichUniversity in 1992andhasbeenheld everyyearsince.
Meeting locations include:
Tokyo,Japan 1992 Toyko,Japan 1998
St.Petersburg, Russia 1993 St.Petersburg,Russia 1999
Nagoya,Japan 1994 Chicago, US 2000
Obninsk, Russia 1995 Chicago,US 2001
Toyko,Japan 1996 Tokyo,Japan 2002
Moscow,Russia 1997
During these meetings, experts in plasma physics, solid state physics, and material
science had an excellent opportunity ofmeeting together, exchanging their views and
opinions, and discussing the latest research results in the field of plasma surface
interactions withbearing upon thehydrogen recycle infusiondevices.
The workshop aimstobring together experts inplasma physics, solid-state physics, and
materials engineering to discuss phenomena ofplasma surface interaction relevant to
hydrogen recycling in fusion devices. The goal of the meeting is to continue and
develop thistradition tohelp atestablishing newscientific contacts.
Ahmed Hassanein Andrey Zakharov
Director ofthe Co-Directorofthe
NATO Advanced Research Workshop NATO Advanced Research Workshop
ix
HYDROGEN ISOTOPES RETENTION IN FUSION REACTOR PLASMA
FACINGMATERIALS:ANABBREVIATEDREVIEW
RION A. CAUSEY,TOM1.VENHAUS1
Sandia National Laboratories,Livermore,CA 94550
ILosAlamos National Laboratories, LosAlamos,NM87545
Abstract
Fusion reactor design requires an understanding of the tritium retention and recycling
properties of the plasma-facing materials. After many years of research, a basic
understanding of theseproperties for materialssuch asberyllium, carbon,andtungsten
hasbeenachieved. Thisreport isanabbreviated review oftheseproperties. The most
widely accepted values (in the opinion of the authors) for diffusivity, solubility,
recombinationratecoefficient,andtrappingparameters foreachofthe above materials
isgiven.
1. Introduction
As fusion reactors move to more frequent use of tritium as a fuel, the retention of
hydrogen isotopes intheplasma-facing components becomes more important. Tritium
isnotonlycostlyanddifficult toproduce, itisalso radioactive. Beingradioactive, itis
absolutely necessary that inventories remain small to mitigate the consequences of
accidental release. This abbreviated review should provide sufficient information on
theretentionproperties oftritiuminberyllium, carbon, andtungsten toallowfirstorder
calculationsoftritiumindifferentfusionreactordesignsemployingthesematerials.
2. Beryllium
Berylliumhas been used extensively inthe JET reactor and is thebaseline material for
the first wall ofITER. Its low Z number and its ability to getter oxygen make it an
attractivefirstwallmaterial. Asaplasma-facing material,thesolubility ofhydrogenin
the beryllium dominates its hydrogen retention characteristics. While several
experimentalprograms [1,2,3] determined relatively moderate values for the hydrogen
solubilityinberyllium, morerecent experiments [4,5,6,7,8,9,10] support theconcept of
near-zero solubility. It isthis extremely low solubility that causes implanted hydrogen
tocome out ofsolution, forming bubbles, andeventually leading to aporous, saturated
surfacelayer. Chernikovetal. [7]clearlyshowedtheevolutionofbubbles with 10keY
D ions at fluences as low as 2xl021Dzcnr', with complete development of connected
A.Hassanein(ed.),HydrogenandHeliumRecyclingatPlasma FacingMaterials, 1-6.
©2002KluwerAcademicPublishers.
2
voids as the fluence was increased beyond that level. The open porosity extended
several microns into the material. While the microscopy of Chernikov et al. showed
direct evidence ofthe formationof aporous saturatedlayer, experimentssuch as those
by Haasz and Davis [10] and Wampler [4] supported these findings at the same time
that they showed the effect of the saturated layer on the total retained hydrogen
isotopes. Both of these studies showed saturation levels of deuterium at lxl021 to
3xl021D/m2, dependingontheenergyoftheionsused. Fortritium,thesevaluesequate
to25to75Ci/m2assuminga50/50mixtureofD andT,veryacceptablenumbers foran
ITER-likedevice.
Codeposition ofhydrogen withberyllium hasbeen studiedby Mayer [11] and
by Causey et al. [12]. While the Mayer experiments [11] used excellent vacuum
conditions, the slow sputtering rate achieved by the use ofan accelerator resulted in
oxygen arrival rates on the sputter deposition plate more than equal to the beryllium
arrival rate. The oxygen contamination resulted in the experiment actually measuring
thecodeposition ofhydrogen withberyllium oxide. Inthe experimentsofCauseyetal.
[12], profuse sputtering was achieved by using the high flux Tritium Plasma
Experiment. Excessive oxygen in the system was gettered early in the experiment by
theinitialsputteredberyllium. Afterafewmonolayersofberylliumweredeposited, the
successive layers contained less and less oxygen. Deuterium retention in the
redeposited layers decreased from a high of about 0.15 DlBe down to a low ofabout
0.02 D/Be. While these value.s are low in comparison to those measured for the
codeposition of hydrogen and carbon (see below), care should be taken to limit the
oxygen ingress into the fusion device to minimize the codeposition with beryllium
oxide.
While using beryllium as a first wall material adds the advantage of neutron
multiplication to assist in tritium breeding, similar nuclear reactions lead to the
production of He6. He6rapidlydecaystoLi6whichabsorbsanotherneutrontoproduce
ahelium atom and a tritium atom. While the amount oftritium bred in the beryllium
varieswiththeneutronenergyspectra,anestimateofthe amountoftritium thatwillbe
produced in a fusionreactor environment can be estimated from the study by Baldwin
and Billone [13]. In their experiments, a sample of theoretically dense beryllium was
exposed to aneutron fluence of5x1026 n/m' with 6%ofthe neutronshaving anenergy
greater than 1MeV. This irradiation resulted in3xl05MBq/g (2530 appm) oftritium.
Scaling these results to fusionreactor conditions, 50Mg ofberyllium in ablanket/first
wall exposed to 3 MWy/m2 fluence would generate as much as 5.5 kg of tritium. In
these experiments, Baldwin and Billone [13] also showed that almost all tritium
produced willberetainedintheberylliumifthetemperatureiskeptbelow about800K.
With the limited uptake oftritium fromtheplasma by theberyllium, thetransmutation
producedtritiumwillquicklydominatethetritiuminventoryforaberylliumfirstwall.
3. Carbon
There are fourmechanismsby whichhydrogen isretained onand incarbon: saturated
layer;absorptiononinternalporosity;trappingontheedgesoftheindividualcrystallites
inthe grains;andcodeposition. The firsttwoofthesemechanismsarenotimportantas