newsletter
newsletter
Vol 2004 / 4August 12, 2004

E UROPEAN F USION DEVELOPEMENT AGREEMENT

News
Issued by the EFDA
Close Support Unit
Garching

Contents• ITER:
Divertor mock-ups
testing
page 2/3

Association EURATOM-CIEMAT (Spain): Sanchez succeeds AlejaldreProf. Carlos Alejaldre, Head of the Association EURATOM-CIEMAT has been appointed by the
Spanish Government as "Director General de Política Tecnológica". He will now have responsibility
for the strategy of the Spanish Government towards the large scientific and technologicalprojects and facilities: fusion (TJ-II, JET, ITER), high energy physics (CERN), structure of matter(ILL, ESRF), space science (Large Telescope at Canary Islands, ESA) and others. The whole
Fusion Community wishes to congratulate Prof. Alejaldre for his prestigious nomination and wishes
him all the best in his new function. He will remain within the Fusion Community as a member of
the CCE-FU (“Consultative Committee for the EURATOM Specific Research and Training
Programme in the Field of Nuclear Energy Fusion”) but he has decided to step down from theleadership of the Association EURATOM-CIEMAT. Dr. Joaquin Sanchez (born in Madrid 1956),
who has been working in fusion at CIEMAT since 1987, has been nominated as Head of the
Research Unit. He started his career in the area of microwave diagnostics and collaborated in the
TJ-I (Madrid, Spain), Wendelstein 7-AS (Garching, Germany) and ATF (Oak Ridge, USA) devices.
In 1989 he became Head of the TJ-I experimental group and since 1993 Head of Diagnostics for
TJ-II. Dr. Sanchez has also participated in the ITER diagnostics effort (as Chairman of the ITPA
Specialists Working Group on Reflectometry) and has collaborated in the EFDA-JET experiments
as Task Force Leader for Diagnostics (2000-2002).

• Associations:ÖAW / Tekes
page 4• Associations:
Czech Republic
page 5• ITER:
Test Blanket Working
Grouppage 6• JET:
Real-time control
at JET
page 6/7• EPS /
Fusion CD-Rom
page 8Dr. Joaquin Sanchez (left) and Prof. Carlos Alejaldre

EESC backs fusion option
The European Economic and Social Committee (EESC) has voiced strong support for thedevelopment of fusion energy approving an opinion submitted to the EESC plenary session on 30th
June. For more information please see our website:

http://www.efda.org

http://www.efda.org>> “Debates and Policy Papers” andhttp://www.esc.eu.int/documents/summaries_plenaries/2004/synt_410_07_04_en.pdf

EFDA Fusion Newsletter

page 2ITER
The neutron irradiation
was carried out in thefission High Flux Reactor
fission reactor located at
the Joint Research Centreof Petten, The Netherlands. It is a light watercooled and moderated
multipurpose research
reactor, which operates at
a nominal thermal powerof 45 MW.

Completion of irradiated divertor mock-ups and material sample testing
The high heat flux testing of neutron-irradiated divertor mock-ups and the characterisation of neutron-irradiated material samples was recently completed at Forschungszentrum
Jülich (FZJ), Germany. This worldwide unique R&D effort has provided essential informationon the performance of the ITER divertor, which is now expected to meet the requirementsof 1000 cycles of 10MW/m2 for 400s and 100 transient cycles of 20MW/m2 for 10s, evenafter a neutron irradiation corresponding to about 10 years of full performance plasma operation.
The effect of energetic neutrons on the performance of the divertor components is an
important issue for ITER and future fusion devices as the material thermal conductivity canbe reduced leading to a potential reduction of the power handling capabilities. In the divertor there are two critical components, the inner and outer divertor targets, where the plasma is allowed to touch the plasma facing material resulting in surface heat loads in therange of 10 to 20MW/m2. Two plasma facing materials being proposed are, Carbon Fibre
Composite (CFC) and tungsten (W). To study the effects of the neutron damage on thesecomponents, irradiation experiments PARIDE 1 and 2 were carried out in the mid Nineties
in the High Flux Reactor (HFR) in Petten (The Netherlands) with a neutron damage of 0.35
displacements per atom (dpa) in carbon at irradiation temperaturesof 350 and 700°C. Post irradiation testing was then performed at
FZJ. Subsequently, a new irradiation programme was launchedwhich consisted of two parts:• PARIDE 3: temperature: ≈200°C; cumulative dpa: ≈0.2 in carbon;≈0.15 in tungsten.
• PARIDE 4: temperature: ≈200°C; cumulative dpa: ≈1.0 in carbon;≈0.6 in tungsten.
The 0.2 dpa (carbon) level corresponds to the integrated neutron damage of the divertor plasma facing components after about
10 years of full performance plasma operation, while the 1.0 dpa(carbon) level is that expected for basic machine components in themain reactor chamber of ITER.
The irradiation mock-ups are similar in design to the proposed
ITER divertor targets and comprise either CFC or W plasma facing
material or armour, joined onto an actively cooled CuCrZr heat sink.
A soft pure copper interlayer between the armour and the CuCrZr
is used to alleviate the joint stresses. Both monoblock and flat tilegeometries were investigated in these experiments. The monoblock
consists of armour tiles with a hole into which a cooling tube isinserted and joined to the tiles. The flat tile geometry consists of ahollow CuCrZr rectangular bar, the cooling channel, on to which theflat plasma facing tiles are joined. Testing of the mock-ups, before and after irradiation,
under the relevant heat flux conditions, was performed in the electron beam facility, JUDITH,
located in a hot cell at FZJ.
In the unirradiated condition both CFC flat tiles and monoblocks surpassed the ITER requirements. The flat tile survived 1000 cycles at both 11.5 and 20 MW/m2 before failing at
23 MW/m2. The CFC monoblock survived 1000 cycles at 19 MW/m2, and 700 cycles at
23 MW/m2. The testing was curtailed at this very high power (about twice higher than the
ITER requirements) because of sublimation of the carbon at the high surface temperatures.
After irradiation to a level of 0.2 dpa, two CFC flat tile mock-ups failed at 19.5 MW/m2.
The 1 dpa irradiated sample testing was limited to 15 MW/m2 due to surface temperaturesof 2500°C causing excessive sublimation. These values are lower than pre-irradiation
values but still surpass the ITER steady-state power handling requirements.

page 3

EFDA Fusion Newsletter

Thermal fatigue testing of a CFC monoblock irradiated to 0.2 dpa was carried out at
10 MW/m2 for 1000 cycles and 12 MW/m2 for 1000 cycles without failure. When the power
was increased to 14 MW/m2 excessive erosion occurred due to high surface temperatures
which made thermal cycling experiments impossible.
W-armoured mock-ups in the flat tile unirradiated geometry were successfully tested for1000 cycles at 8 MW/m2 and 14 MW/m2 (this is absorbed power density, the surface heat
flux is approximately double this value). After irradiation however, a failure occurred at
approximately 10 MW/m2. Post-mortem metallography showed detachment of the armour
tiles at the W/Cu joint caused by irradiation-induced embrittlement of the pure Cu.
In contrast to the flat tile geometry, the W monoblocks showed no degradation in thermal fatigue performance, even after irradiation, and all survived 1000 cycles at 18 MW/m2.
Thermal conductivities were determined for the CFC material grade NB31 and the corresponding silicon-doped material NS31, produced by Snecma Propulsion Solide, France,
before and after irradiation. As expected, the thermal conductivities were reduced significantly by the irradiation and the reduction increased with increasing neutron dose. For all
three directions of the anisotropic CFC, the room temperature conductivity was reduced to
17% of the unirradiated value after 0.2 dpa (to 10% after 1 dpa). The effect of neutron irradiation on the thermal conductivity at high temperature was smaller (33% of the unirradiatedthermal conductivity was measured at 700°C). Furthermore, a significant recovery of the
CFC thermal conductivity (up to 80% of the unirradiated value) was observed during thepost-irradiation high heat flux test. The thermal conductivities for the silicon-doped material
NS31 and their neutron-induced degradation were comparable with those of NB31.

JUDITH is a 60 kW powerful high heat flux testing
facility operated at the
Forschungszentrum Jülich
(FZJ), Germany. It is used
to simulate the cyclic thermal loads, which act on
the plasma-facing components of a fusion reactor.
Being located in a hot cell,it can test irradiated mockups with or without
beryllium armour. A new
facility, named JUDITH-2,
is under construction at
FZJ with a larger vacuum
chamber and a 200 kW
electron beam gun.
Its completion is plannedby the end of 2004.

Pure tungsten and W-1%La2O3 were also tested in the unirradiated state and after irradiation in the PARIDE 3 and PARIDE 4 campaigns. Both materials showed a very small thermal conductivity degradation. At room temperature, it was reduced to 80% and 73% of theunirradiated value after 0.15 and 0.6 dpa, respectively. But at higher irradiation temperatures annealing became effective, and the conductivity degradation was negligible.
Important conclusions have been derived from the results of the testing of irradiateddivertor mock-ups and material samples. The effect of the neutron damage on the performance of the mock-ups is greater in a flat tile than in amonoblock geometry, probably because the strain
range in the pure Cu interlayer during operation is afactor of three higher in the flat tile configuration andthis material rapidly becomes very brittle under irradiation. The thermal conductivity degradation in the
CFC was determined and showed a significant
recovery after the high heat flux testing. The dataobtained in these experiments demonstrate that theeffect of about 10 years full performance plasma
operation in ITER will only cause an increase of the
ITER CFC outer divertor target temperature by, at
most, about 400°C under the reference normal operation power load of 10MW/m2. In reality, as the neutron irradiation takes place in ITER the CFC target
will be eroded contributing to a reduction in the surface temperature, which will be remain close to its
reference value (about 1500 °C) throughout the ITER
divertor target lifetime. It is also important to note thatthe measured degradation of the W thermal conductivity under irradiation should not represent a major
JUDITH facility at FZJ
issue for the operation of ITER with a W target.

For more information see:
http://www.fz-juelich.de/portal/
http://www.jrc.nl

EFDA Fusion Newsletter

page 4

Associations
ÖAW: 15th Association Day on Plasma Physics
For more information on
the Association EURATOMÖAW please see:
http://www.oeaw.ac.at/euratom

On 16th June 2004 the Association EURATOM-ÖAW (Österreichische Akademie derWissenschaften – Austrian Academy of Sciences) organised its annual Association Day on
Plasma Physics at the University of Innsbruck (Austria). At this meeting the Austrian
research groups active in this field presented their contributions to the physics programme
and recent results. Guest lectures were given by Dr. David Coster (Association EURATOMIPP Garching, Germany) on integrated tokamak modelling and Dr. Shakeib Arshad (EFDAJET) on international collaboration at JET.

From left to right: Prof. Siegbert Kuhn (Univ. Innsbruck), Prof. Dumitru Luca (Al.I. Cuza Univ. Iasi, Romania),
Prof. Ferdinand Cap (Univ. Innsbruck), Prof. Hannspeter Winter (HRU), Dr. Richard Kamendje (TU Graz),
Prof. Roman Schrittwieser (Univ. Innsbruck), Prof. Klaus Schöpf (Univ. Innsbruck)

The meeting ended with ashort celebration on the occasionof the 80th birthday of Prof.
Ferdinand Cap. Prof. Cap founded
the Department of Plasma Physics
at the University of Innsbruck inthe early 1960s and contributed tothe inception of the Commission
on the Coordination of Fusion
Research in Austria (KKKÖ) at theAustrian Academy of Sciences in
1980s. The KKKÖ supports incentive projects in the field of fusion.
Prof. Cap is an Austrian pioneer in theoretical plasma physics
and has always been a vigorous
supporter of the Austrian fusion
research.

10th Tekes Association Annual Seminar

Additional informationon the activities of the
Association EURATOMTekes can be found fromthe web-sites:
http://akseli.tekes.fi/Resource.p
hx/enyr/fusion/en/index.htx

and
http://www.vtt.fi/pro/research/fu
sion2003_06/indexe.htm

The Annual Report 2003:
http://www.vtt.fi/inf/pdf/publications/2004/P530.pdf

The 10th Annual Seminar of the Association EURATOM-Tekes was held at the Tampere
University of Technology on 1-2 June 2004. Over 50 fusion physicists and engineers representing Tekes, VTT, universities and industry participated in the seminar. The talks andposters presented a summary of the research activities of the Finnish Association during
the past twelve months. The topics covered Tekes contributions to the EFDA JET work programme, EFDA technology programme and ITER-related industrial activities. The clear
focus areas of the Tekes activities are scientific exploitation of JET in physics and the vessel/in-vessel field in technology. These cover over 70% of the Finnish fusion effort.
Physics presentations included the recent trace-tritium experiments at JET and predictive integrated transport modelling of JET plasmas, material transport studies in the ASDEX
Upgrade (Germany) tokamak and molecular dynamic simulations of hydrocarbon sticking
and tungsten blistering. Technology-related talks dealt with in-situ mechanical testing ofmaterials under neutron irradiation, virtual reality techniques and water hydraulic manipulators in ITER divertor maintenance, welding robot system and beam welding studies.
Contributions from industry concerned development of advanced superconducting wires by
Outokumpu and 3D forming of thick stainless steel plates for ITER vacuum vessel manufacturing by Hollming Works.
The EFDA Leader, Prof. Minh Quang Tran gave an invited talk on European contributions to ITER covering the fusion technology aspects and heating systems. The main message of his presentation was that Europe has expertise in all key technologies needed for
ITER. His presentation inspired a lively discussion on ITER and future EFDA activities.
The freshly published Annual Report 2003 of the Association EURATOM-Tekes was distributed to seminar participants.

page 5EFDA Fusion Newsletter

Associations
Additional information isavailable at:

Association EURATOM-IPP.CR
The fusion programme in the Czech Republic is coordinated by the Association
EURATOM-IPP.CR, which was established in 1999. The Institute of Plasma Physics,
Academy of Sciences of the Czech Republic (AS CR) performs the research together withsix other national partners:• J. Heyrovsky Institute of Physical Chemistry AS CR, Prague• Nuclear Physics Institute AS CR, Prague• Faculty of Mathematics and Physics, Charles University in Prague,• Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University,
Prague• Nuclear Research Institute plc, Rez• Institute of Applied Mechanics Ltd, Brno

http://www.ipp.cas.cz
http://www.ujf.cas.cz/
http://www.mff.cuni.cz/
http://www.jh-inst.cas.cz/
http://www.fjfi.cvut.cz/
http://www.nri.cz/
http://www.uam.cz/

The total staff resources amount to about 40 ppy. The experimental programme inphysics is based on the small-size tokamak CASTOR (R = 40 cm, a = 8 cm, B = 1.3 T, I =15 kA), which has been operational in IPP Prague since 1977. The experimental programme focuses on the study of processes in the edge plasma (in particular plasma turbulence), wave plasma interactions and the development of advanced diagnostic systems.
Experiments on the CASTOR tokamak are accompanied by relevant theory and modelling.
In addition, fusion-relevant atomic data are obtained (interaction of hydrocarbon ions withgraphite targets).
The research is performed in a close international collaboration. Colleagues from the
Associations EURATOM-CEA, Etat Belge, ÖAW and ENEA (RFX) frequently participate in
CASTOR experiments. Czech physicists regularly work on TORE-SUPRA, TCV, MAST and
TJ-II. So that the international collaboration is bi-directional. The expertise of Czech scientists is also exploited through participation in the JET programme. They are involvedin the study of edge plasma (fluctuation and flow measurements using electric probes), andof the generation of fast particles in front of the Lower Hybrid grill.
Participation in the EFDA Technology programme is basically focused on the ITER project. A light water fission reactor isused for irradiation of first-wall materials and candidate Hall
probes (for measurements of the tokamak magnetic field) and to
study breeding blanket issues. Furthermore, the Association is
involved in the simulation of the welding of the vacuum vessel,and mechanical testing of the first-wall panels attachments.
A cyclotron is used to collect nuclear data relevant for the IFMIF
project. The unique water-stabilised plasma torch is used for plasma spraying of tungsten.
An essential part of our work is the education of the young
generation of fusion scientists. A course on “Physics andTechnology of Nuclear Fusion” is organised for three faculties
in Prague and supervise diploma and PhD theses of students.
Furthermore, together with Hungarian colleagues (Association
EURATOM-HAS), an annual Summer Training Course for 10-12
graduate and PhD students, exploiting the unique features of
the CASTOR tokamak for the practical training of domestic andforeign students is organised, with particular emphasis on
those from newly associated countries (Hungary, Slovakia, Bulgaria, Estonia).
A regular scientific audit and invaluable help is provided by the International Board ofAdvisors, which consists of nine European fusion experts. The annual meeting of the Boardis accompanied by the Association Day, where the results achieved and future plans are
discussed in detail.
The Association also contributes to public information activities, such as a number oflectures, open days, and the recently published brochure “Fusion for everybody” (in Czech).

The CASTOR tokamak

EFDA Fusion Newsletter

page 6ITER
Test Blanket Working Group (TBWG)
The ITER Test Blanket Working Group (TBWG) was re-established in September 2003
and convened for the third time at EFDA Garching (Germany) from 7 to 9 July 2004. Fourmembers of the ITER International Team and up to three members from each of the ITER
Participants (China, EU, Japan, Russian Federation, South Korea, USA) contribute to thegroup. The main mission of the TBWG is to develop the Design Description Document for
the Test Blanket Modules (TBMs) proposed by the participants, to promote collaborations in
R&D and sharing of common TBM features and to define a coordinated TBM test
schedule for the first 10 years of ITER operation.
Three horizontal ports of the ITER machine are reserved for the installation of DEMOrelevant TBMs capable of achieving sufficiently high tritium breeding ratios and thermal
efficiencies for electricity production. The six ITER Participant Teams are proposing
different types of breeding blanket
concepts for the TBMs such as
He-cooled or water-cooled ceramic/Be, He-cooled or dual cooled
LiPb, self cooled Li concepts, etc.
ITER will supply unique testing
conditions for the TBMs underfusion-relevant conditions, although, due to the low neutron
fluence, long-term irradiation
damage in the materials cannot be
addressed. It will be a big challenge to install the different types
of TBMs in ITER in an integrated
and harmonised way due to thelimited available space in the ports
and in the building. All the proposed TBMs have to pass stringent qualifications and acceptance tests before installation inorder not to jeopardise the operation of ITER.

JET
Real-time control at JET
It is increasingly clear that real-time control is expected to play a crucial role in experiments based on magnetically confined plasma. From the early years of fusion researchwhere the experimental scenario was 'hard-wired' and used elementary electronic control
over a few key parameters, research has moved towards a completely different setup. Thevery fast response of today's computing and control systems gives the opportunity of extensive real-time control and data analyses. Real-time tools can not only precisely tailor key
plasma parameters and keep them under control, but can also run several consecutive
experiments within a single plasma discharge. This latter feature is very significant now that
JET's plasma discharges may last tens of seconds - and will be in future superconducting
facilities where plasmas could potentially extend over tens of minutes.
JET represents today the most spectacular experiment in terms of real-time control of aplasma. On JET, scientists leading the experimental sessions, are able to control a numberof parameters in the same time, and space resolution, providing flexibility in experimental
output between each plasma discharge.

EFDA Fusion Newsletter

page 7

Real-time measurements of neutrons, magnetic
flux, plasma temperature, density, helicity, electromagnetic radiation (X-ray, UV, visible and IR) provide inputs
for real-time analysis of magnetic fields, confinement,
spectral lines, chemical composition, and profiles oftemperature, density and current. There are over 500
signals involved, updating every few milliseconds andtravelling over a high speed digital computer network(ATM), similar to those used by telephone companies
in their backbone exchanges, designed to deliver setsof signals (datagrams) from different sources to theappropriate destinations.
Magnetic coils, gas valves, Neutral Beam Injectors(NBI), pellet injectors, Ion Cyclotron ResonanceHeating (ICRH) and Lower Hybrid Current Drive(LHCD) systems can all act as actuators in JET. Two
examples can give an idea of how challenging the task
is: the control of the heat power load and the extreme
plasma shape control.

Figure 1: Strike point control and sweeping.
Left diagram shows the relative position of the divertor and the strike points with respect
to the plasma and the first wall. Right diagram zooms into the details of the plasma
exhaust lines interacting with the divertor.

The control of the power applies in particular to the X-point configuration. Here the particles escaping from the plasma and, following the field lines outside the separatrix, collidewith the walls in two points called "strike points". This highly concentrated energy flow, delivering most of the energy output from the plasma, needs to be directed onto the divertor,
where the thermalmechanical design and properties of the material can sustain the high thermal load (see fig. 1). Nevertheless, a prolonged and focused heat load could damage eventhe divertor and, to prevent such damage, the only possible solution is spreading the heat bysweeping the strike points over a wider area of the divertor. That means that it is the real-time
control of the magnetic configuration which guarantees the integrity of the machine.
A further example is the implementation of the so-called Extreme Shape Control(XSC). In order to obtain reference scenarios with high quality H-mode plasmas at a plasma density close to the Greenwald density (for example through high triangularity andelongation) the control system at JET has been recently modified to maintain the plasma
shape in the presence of large disturbances (e.g. giant edge localised mode [ELMs] andlarge variations of bp and/or li). The system has been successfully installed and commiss
i
o
n
e
d
during the last experimental campaign
and proven during a set of high triangularity ITB discharges with bp up to 1.5(fig. 2) and/or bli up to 0.5.
In conclusion, as one of the recent
tools developed in JET, the real-timeequilibrium, together with real-time electron and ion temperature and current
profiles measurements, has dramaticallyenhanced the experimental work on the
integration of advanced tokamak scenarios and, in particular, the development oftechniques to control in real-time the qand pressure profiles simulta-neously inreal-time.

time (s)Figure 2: High beta experiment with XSC

All these examples show the increasing role of real-time control at JET anddemonstrate that this is an asset with animportant role in exploring and preparing
new scenarios for the first phase of the
ITER operations.

ELM:
An instability that often
occurs in short periodic
bursts during the H-mode
in divertor tokamaks.
It causes transient heatand particle loss into thedivertor which can bedamaging. Small ELMs
are useful for impurity/
density control.

EFDA Fusion Newsletter

page 8

Events31st European Physical Society Conference on Controlled Fusion
London has always been an important centre of modern life, a point of intersection between science, arts and technology, trade and commerce. This year,
from 28th June to 2nd July, Imperial College, which is located in London’s South
Kensington district, hosted the 31st European Physical Society (EPS) conference on plasma physics and fusion research with about 800 international
participants. This time the science of laser-plasma interaction and inertial confinement fusion, as well as dusty and low temperature plasmas, had substantially greater prominence than previously. The conference was opened with a
special address from Professor Sir David King FRS, Chief Scientific Advisor to
the UK Government. Through its Plasma Physics Division, the EPS awards
every year the Hannes Alfvén Prize for outstanding contributions in theory or
experiment. This year’s award-winners are Dr. J.W. Connor, Dr. R.J. Hastie and Dr.
J.B. Taylor, from the UKAEA Culham Division (UK) “for their seminal contributions to a wide range of issues of fundamental importance to the success ofmagnetic confinement fusion, including the development of gyrokinetic theory,the prediction of the bootstrap current, relaxation theory, dimensionless scaling
law, pressure-limiting instabilities, and micro-stability and transport theory.” The 32nd EPS 2005
conference will be held at the Congress Palace of Tarragona, on the east coast of Spain, theso-called Costa Dorada (Golden Coast), from 28th June to 1st July.

For more information
please see:
http://www.fusion.org.uk/eps2004/index.html

andhttp://eps2005.ciemat.es/main.shtmlPromotion
For more information
see our EFDA website:

New CD-Rom on Fusion available“Fusion – an energy option for the future” is the title of the new CD-Rom issued by
EFDA in June 2004. It aims at explaining the fundamental principles of fusion and thestatus of European research in this field. The information is based on the activities
carried out by the European fusion community. The CD-Rom was produced by the
Association EURATOM-FOM in cooperation with EFDA and with the financial support of
the European Commission. It is available free of charge (for didactic purposes only)
through EFDA (Federico.Casci@efda.org).

http://www.efda.org

and additionally
http://www.jet.efda.org
http://www.iter.org

EFDA Close Support Unit - Garching
Boltzmannstr. 2
D-85748 Garching / Munich - Germany© M.Q. Tran (EFDA Leader) 2004.

phone: +49-89-3299-4237
fax: +49-89-3299-4197
e-mail: federico.casci@efda.org
editors: Federico Casci, Doris Lutz-Lanzinger
graphic design: Karen Jens

The EFDA Parties are the European Commission and the Associates of the European
Fusion Programme which is co-ordinated and managed by the Commission.
Neither the Commission, the Associates nor anyone acting on their behalf is responsible
for any damage resulting from the use of information contained in this publication.

This internal newsletter or parts of it may not be reproduced without permission.
Text, pictures and layout, except where noted, courtesy of the EFDA Parties.