European Fusion Development Agreement

Fusion Expo

Original idea (1993):

P.J. Paris (CRRP-EPFL, Lausanne - CH)W. Kienzle (CERN, Genève - CH)

Adaptation (2001):

Texts:B. de Gentile (CEA/Cadarache - F)R. Saison (DG Research, European Commission)D. Bartlett (DG Research, European Commission)F. Casci (EFDA - Garching - D)W. Spears (ITER/JCT - Garching -D)

Graphics:H. Desmedt (Assoc. Euratom - CEA/Cadarache - F)

Technical support:E. Maier (Assoc. Euratom - IPP/Garching - D)

Funding:

European Fusion Development Agreement (EFDA)

Printing:

©CEA 2002Printed in France

Contents

Section A Introduction: from Plasma Physics to Fusion Energy R&D 4

Section B Inertial Confinement Fusion:Energy from micro-explosions 24

SectionC: Magnetic Confinement Fusion:Ever improving Tokamak Plasma Performance 26

Section D: Fusion R&D in Europe 44

Multimedia: CD-Rom explaining Fusion

Suggested Bibliography:

Tokamaks (second edition)John WessonOxford Science Publications (1997)ISBN 0-19-856293-4

Website of the European Fusion Information Network:http://www.fusion-eur.orghttp://www.efda.org

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The world population has doubled from 3 to 6 billion peopleduring the last 40 years and will rise to 8-12 billion people by2100, most of the increase occurring in developing countries.

Possible energy savings in the industrialised world will bes t rongly outweighed by the increasing needs of the developingworld: diff e rent scenarios indicate at least a doubling, if nottripling, of primary energy demand during the next century.

E n e rgy supplies, both sufficient and reliable, are essential forensuring an adequate standard of living.

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Introduction: from Plasma Physics to Fusion Energy R&D

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In Europe, energy imports re p resent a substantial fraction (50%in 1999) of total consumption. This fraction is expected to gro wto about 70% in coming decades. Energy sources having thepotential to meet such energy needs are: fossil fuels, re n e-wables, nuclear fission and - in the longer term - fusion.

G l o b a l l y, fossil fuel re s o u rces are finite and their use is nowc o n f i rmed as a serious threat to the global enviro n m e n t .Although the potential of renewables is large, their capability top rovide base-load energy is questionable. A substantial fractionof our energy needs could be provided by nuclear fission,which has to solve public acceptability problems. Sustainable ,C O 2 - f ree energy sources are necessary in the long term.

Fusion can help providing energy for millennia: the primaryfuels are abundant and widely available (for example in thesea). More o v e r, fusion is well-suited for base-load electricitygeneration. Fusion has inherent advantages with respect tosafety and environment; in part i c u l a r, there is no emission ofg reenhouse gases.

Fusion should be a part of the long term energy mix.

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Introduction: from Plasma Physics to Fusion Energy R&D

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Fusion is the nuclear reaction which creates energy in starslike the sun: nuclei of low mass atoms combine - or "fuse" - tof o rm heavier ones. In the core of the sun (at temperatures of10 - 15 million °C), hydrogen fuses into helium: this pro c e s sp rovides the energy which, as solar radiation, sustains life one a rth.

In the sun, the "fuel" is heated and confined by gravity. One a rth, confinement must be achieved by other means andfusion re q u i res a temperature above 100 million ° C (ten timesthe temperature of the core of the sun).

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The development of plasma physics started in the 1920s in ane ff o rt to understand the energy source of the stars.

When a gas is strongly heated, its electrons become complete-ly separated from the atomic nuclei (ions). This ionised gas, agood conductor of electricity, is called "plasma" (the fourt hstate of matter). More than 99% of the universe is plasma.

Plasma physics was given an impetus when the idea thatfusion reactions might be the source of energy in the starswas put forward by Atkinson and Houtermans (1928).

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Introduction: from Plasma Physics to Fusion Energy R&D

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The fusion reaction which is easiest to produce on earth is thatbetween the two isotopes of hydrogen: deuterium (D) and tri-tium (T). The reaction products, an alpha-particle (i.e. thenucleus of a helium atom) and a neutron, have an overall(kinetic) energy of 17.6 MeV. One gramme of D-T fuel couldgenerate 100,000 kilowatt-hours of electricity: about 8 tonnesof coal are needed to supply the same energ y !

Deuterium can be extracted from water (on the average, 30ga re contained in every cubic metre). The radioactive tritiumisotope exists in negligible quantities on earth, but can beb red from lithium, a light metal which is abundant in the ear-t h ’s crust and in the sea.

Tritium breeding is achieved thanks to the neutron produ-ced by the fusion reaction on Lithium. The fuel cycle forfusion is finally Deuterium + Lithium gives Energy +Helium.

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Introduction: from Plasma Physics to Fusion Energy R&D

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Fusion reactions occur when the nuclei have sufficient velocityto overcome the repulsive forces of their electrical charges. Inthe case of D-T reactions, temperatures above 100 million °Ca re needed, well above the temperature where a gas is ioni-sed and becomes a “plasma”.

To reach such temperatures, powerful heating is necessaryand losses must be kept to a minimum by holding the hotplasma thermally insulated from the material walls.

This is a challenging task, both in terms of the understandingof the complex physical processes which is re q u i red, and theneed for sophisticated new technologies.

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Introduction: from Plasma Physics to Fusion Energy R&D

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Magnetic Confinement Fusion, which makes use of magneticfields to ensure thermal insulation perpendicular to the magne-tic field. Losses are reduced by closing the magnetic configu-ration on itself (doughnut-shaped ring).

Magnetic Confinement Fusion uses a very low-density fuel(less than ambient air density), and confines the plasma ener-gy for the order of seconds. It allows steady state operation.

I n e rtial Confinement Fusion uses ultra high power lasers or ionbeams to heat and compress a minuscule fuel pellet to about1,000 times solid density, until ignition occurs in its core ands p reads outward s .

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Introduction: from Plasma Physics to Fusion Energy R&D

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The fusion reactor is a furnace: there is at any moment verylittle fuel in the reaction chamber (about 1 g of D-T in 1000m3). In case of malfunction, the fusion burn lasts only a fewseconds and core melt-down is impossible.

The basic fusion fuels (deuterium and lithium), as well as theash (helium), are non-radioactive. The necessary interm e d i a t efuel, tritium which is radioactive (12 years lifetime), will bep rocessed and burnt on-site, by breeding the needed amountof lithium in a “blanket” around the plasma.

The fusion reaction produces radioactivity (neutron, alpha), thehot plasma also emits X-rays, but this radioactivity stops whenthe reaction stops.

A fusion reactor can be designed such that the "worst case"scenarios of any in-plant accident will not re q u i re evacuationof the nearby population.

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Introduction: from Plasma Physics to Fusion Energy R&D

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Fusion reactors do not produce greenhouse gases - such asCO2, SO2 and NOx - which can harm the environment andcause substantial climate change.

If current developments look like leading to an economic ener-gy source, foreseeable technological developments will makethe fusion reactor even more environmentally attractive, byminimising the tritium inventory and using advanced, low acti-vation materials for the stru c t u re.

The neutron load on the materials of the internal stru c t u relimits their lifetime and generates radioactive waste. Thiswaste, similar in volume to that of light-water reactors, couldbe re-used after about 100 years.

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Introduction: from Plasma Physics to Fusion Energy R&D

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L a rge power plants are needed to satisfy the increasing needsof large cities. Basically, only the core of a fusion re a c t o r( reactor vessel with blanket, magnets and mechanical stru c t u-re) will be diff e rent from that of fossil or fission power plants.The other parts of the re a c t o r, up to the turbines generatinge l e c t r i c i t y, will be similar.

A fusion power station will consume only very small quantitiesof fuel. For comparison:

- in a 1 GWelectric coal-burning power plant, more than 3 mil-lion tons of hard coal are re q u i red per year (more than 400railway wagons per day);- with a 1 GWelectric fusion plant, less than 100 kg of deute-rium plus about 3-4 tons of natural lithium would be needed fora whole year (i.e. just one small truck load per year).

Cheap fuel for fusion is abundant: supplies would last for mil-lennia. In fossil fuel power stations, fuel costs are the main fac-tor determing electricity generating costs. For a fusion powerstation, the major costs will be for construction, decommissio-ning and periodic replacement of internal components.

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Introduction: from Plasma Physics to Fusion Energy R&D

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I n e rtial confinement fusion for peaceful purposes relies on trig-gering "micro-explosions" of D-T pellets.

A "driver" - an intense laser or ion beams - illuminates a tinycapsule (diameter of order 1 mm) containing D-T fuel, andrapidly heats its surface. The fuel is compressed by the inwardpush of the hot surface plasma. The core of the pellet ignitesand the thermonuclear burn spreads out through the entirec o m p ressed fuel.

I n e rtial confinement fusion is necessarily produced in verys h o rt, repeated pulses . However, the path to an inertial fusionreactor is still very long.

The European fusion programme has a “watching brief“ oni n e rtial confinement R&D, to assist co-ordination of civilianre s e a rch in this are a .

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Magnetic Confinement Fusion uses a hot plasma fuel confinedwithin the reactor chamber by means of magnetic fields: theelectrically charged particles of the plasma, ions and elec-t rons, circle around magnetic field lines and thermal lossesperpendicular to the field are strongly re d u c e d .

The magnetic fields are generated by coils locateda round the reactor chamber and, for certain classes ofdevices, by currents flowing in the confined plasmai t s e l f.

Magnetic Confinement Fusion allows for a steady-state fusionb u rn .

The European programme concentrates on the development of magnetic confinement fusion.

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In the early days of fusion R&D, linear configurationswere used, such as "mirror" machines: in a cylindricalplasma vessel, magnetic fields parallel to the axis confinethe particles radially; losses at the cylinder ends couldonly be reduced by methods which reflect, or "mirror", afraction of particles back into the vessel.

Losses parallel to the field can be suppressed by bendingthe cylinder on itself to form a ring (torus). Magnetic fieldis then called ”toroidal field” as it is oriented along thetorus. However, this is not sufficient: the plasma ringwould expand under its own pressure (like a tire) and hitthe walls of the vessel.

Therefore an additional ”poloidal field” is added to resistthe expansion. The poloidal and toroidal field coils can bekept separate, as in a tokamak, or combined, as in a stel-larator, and each configuration has its own advantages.

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In the tokamak, a strong toroidal field (several Tesla) is pro d u-ced by coils placed around the toroidal reactor vessel.

A large toroidal current (10 to 20 million Amperes in areactor) is induced by transformer action in the plasmaand generates the poloidal magnetic field. As a transfor-mer cannot generate continuous dc current, the plasmacurrent must be sustained by other means.

The stellarator does not rely on a toroidal plasma current:its magnetic configuration is non-axisymmetric and is pro-duced by either two sets of interlocked coils or (for a reac-tor) one set of non-planar coils around the vessel.

Stellarators have the inherent potential for continuous operation.

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As in any solid conductor, an electric current heats the plasmat h rough which it flows. This is due to collisions of the electro n swith the other plasma particles.

H o w e v e r, such heating has its limitations due to the fact that:• as the temperature increases, the collision ratedecreases, and therefore ohmic heating becomes lessand less effective;• even with perfect confinement, energy is lost by elec-tromagnetic radiation from the plasma electrons.

The plasma temperature saturates at a few tens of million °C,when the losses just compensate the ohmic heating.

For thermonuclear fusion burn in a re a c t o r, 10 times higherplasma temperatures are needed.

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In Neutral Beam Injection, a beam of charged particles isp roduced in an ion source, accelerated to high voltages(100,000 volts or more) and neutralised through a gas cell(neutraliser). The neutral beam does not feel the magneticfields and penetrates into the plasma where it is absorbed anddelivers its energy (through collisions) to the plasma electrons.

H i g h - F requency heating uses high-power radio-waves whichresonate with the plasma particles in the magnetic field.E n e rgy can be transmitted to the plasma, thus heating it. TheIon Cyclotron Resonance heating and the Electron Cyclotro nResonance heating are the most commonly used.

Lower Hybrid heating is also used in some current tokamaks.

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The high energy helium nuclei (or alpha particles) re l e a s e df rom fusion reactions collide with other plasma particles andso heat the plasma. When fusion reactions become self-sustai-ning, i.e. when all plasma energy losses are compensated byalpha particle heating, the plasma is said to be ignited. Thefuel can then, in principle, continue to burn by itself (i.e.without need for auxiliary heating).

A l t e rn a t i v e l y, the plasma might be kept just below ignition, ina ”driven burn” mode. This would allow fine control of theplasma operating point using the external heating.

In any case a certain amount of additional heating power isalways needed for burn control. In devices with a plasma cur-rent (e.g. tokamaks), heating systems are needed to sustainthe plasma for long-pulse, or stationary, operation.

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The neutrons released from fusion reactions do not interactwith the plasma: they escape from the burn chamber and areslowed down in a "blanket" surrounding the reactor core. Theblanket contains lithium and the absorbed neutrons transformlithium into tritium which is extracted and processed forrefuelling (together with deuterium) of the plasma. In a powerre a c t o r, the heat is used to generate steam which drives tur-bines and generates electricity.

T h e re are also number of auxiliary systems:

• for refuelling (by gas puffing, solid pellets or neutral beams)• for exhaust of power and particles due to plasma losses• for exhaust of the ash (helium) and of impurities fro m

the reactor core• diagnostics for control and operation of the re a c t o r

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To measure the pro g ress in fusion R&D, a figure of merit - Q -is commonly used: this is the ratio of fusion power pro d u c e dto the heating power into the plasma.

So far, tokamaks have reached the best perf o rm a n c e :Q ~ 1 (breakeven) in JET (the large European tokamak, theonly device in the world capable of operating with real fusionfuel) and, extrapolated from operation in deuterium only, inJ T-60, the large Japanese tokamak.

This re p resents an increase in perf o rmance by about 10,000since 1968 when the T3 tokamak in the USSR demonstratedhot plasmas for the first time.

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The "study of fusion, with particular re f e rence to the behaviour ofan ionised plasma under the action of electromagnetic forces" wasp a rt of the initial programme of Euratom in 1958.

Magnetic fusion in Europe focused on several toroidal confinementschemes during the 1960s and then concentrated on the tokamakduring the 1970s. The construction of the large Joint Euro p e a nTo rus (JET) was decided by the Council of Ministers on 30 May1978. The essential objective of JET was "to study a plasma inconditions and dimensions approaching those needed in a ther-monuclear reactor". JET has reached, and sometimes exceeded, allits original milestones.

Specialised toroidal devices - including stellarators and re v e r-sed-field pinches - were also built during the 1970s and1980s in Europe. These devices, plus the work on technologi-cal issues of fusion, complement the tokamak R&D.

The European Fusion Development Agreement (EFDA) aims ats t rengthening the co-operation and the collaboration on fusionin Euro p e .

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The long-term objective of fusion R&D in the MemberStates of the European Union (plus Switzerland and theseven countries associated to the Euratom FrameworkProgramme) is "the joint creation of prototype reactors forpower stations to meet the needs of society: operationalsafety, environmental compatibility, economic viability".

The strategy to achieve this long-term objective includes thedevelopment of an experimental reactor ("Next Step"), follo-wed by a demonstration reactor (DEMO), accompanied byphysics and technology R&D activities which also involveE u ropean industry .

The potential contribution of fusion to safe and clean base-load electricity generation is investigated in the wider contextof studies on the socio-economic aspects of fusion.

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In the context of the European strategy, the construction of anexperimental reactor is a major milestone and, in the light ofp ro g ress to date, seems technically feasible during the nextdecade. For the period 1998-2002, the aim of E u ro p e a nfusion R&D is to further develop the necessary basis for thec o n s t ruction of an experimental re a c t o r.

T h e re are three main lines of activities:

• Next-step activities: fusion physics and technology activitiesto develop the capacity to construct and operate an experi-mental re a c t o r ;• Concept improvements: stru c t u red physics activities toi m p rove basic concepts of fusion devices, towards pre p a r i n gthe Next Step and the conceptual definition of a demonstra-tion re a c t o r, DEMO; • Long-term technology: stru c t u red technology activitiest o w a rds preparing, in the longer term, for DEMO and thena prototype re a c t o r.

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The purpose of work on concept improvements is to exploreoptions and to pre p a re, in the longer term, for the definition ofDEMO.

C u rrent devices also serve for fundamental fusion physics studies,for the development of diagnostics, for the preparation of collabo-ration on larger devices, for innovative studies and for the trainingof young professionals; also, these are the links which allow theincorporation of University re s e a rch into theoretical, numerical ordiagnostic activities.

Work has been undertaken on JET and in the associated laborato-ries with their specialised tokamaks and in the accompanying pro-grammes of Member States without Association. Work on stellara-tors (which have the intrinsic potential for steady-state operation) ispursued and a new large device (Wendelstein 7-X) is underc o n s t ruction.

Contributions to the toroidal confinement data base are pro v id e dby the reversed-field p i n c h .

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A number of diff e rent concepts are being explored for bre e d e rblankets. These have to work at sufficiently high temperature top rovide hot enough coolant to generate electricity eff i c i e n t l y, whileb reeding at least one tritium atom for every reaction in the plasma.E u ropean studies concentrate on the use of water-cooled lithium-lead, and on helium-cooled ceramic breeder pebbles.

To realise the full potential of fusion, low activation materials needto be developed and qualified for nuclear use. European develop-ment concentrates on reduced activation ferritic and mart e n s i t i csteels and, looking further ahead, at silicon carbide.

To continually assess the potential of fusion development, powerreactor design studies are regularly undertaken. These study socio-economic aspects, and examine long term prospects. They are alsoa means for assessing the environmental impact of to widespre a duse of fusion power re a c t o r s .

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Achievements in Euro p e ’s associated fusion laboratories haveenabled pro g ress which none of the Member States wouldhave been able to achieve alone. On JET, the world’s biggestand highest perf o rmance tokamak, 16 MW fusion powerw e re produced in 1997.

JET is presently the only fusion device in the world capableof operating with the real fuel (D-T) of future fusion powerstations.

Behind this success stands the work of about 2,000 physi-cists/engineers in European associated laboratories and inE u ropean industry.

The construction of the first experimental fusion re a c t o r, whichis necessary for the further pro g ress of fusion R&D, can nowbe envisaged on a basis of scientific and technical confidence,and could start during the next decade.

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Fusion R&D in Europe is implemented within theframework of:

• agreements of association with organisations”Associations” in, or acting for, Member States (andAssociated States) for activities in physics, plasma engi-neering and technology; • other contracts of limited duration;• the European Fusion Development Agreement (EFDA)incorporating technology activities in the associations andE u ropean industry, the collective use of the JET facilities, aswell as the European contribution to international collabora-tions such as ITER; • the agreement for the promotion of mobility of re s e a r-chers, and Marie Curie Fellowships.

The overall yearly expenditure is presently about 450MioEURO, of which about 200 MioEURO come from theCommunity budget.

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All Associations have undertaken work for, or in collaborationwith, other Associations; also, they were partners in JET andEFDA, and carried out work for them through variouscontracts.

A c ross Europe there exists a genuine scientific and technicalcommunity of large and small laboratories directed towards acommon programmatic objective. Intern a t i o n a l l y, the mosti m p o rtant collaboration is ITER under the auspices of theI n t e rnational Atomic Energy Agency (IAEA, Vienna). The ove-rall programmatic objective of ITER is to demonstrate thescientific and technological feasibility of fusion energy for pea-ceful purposes.

Also, Implementing Agreements in the frame of theI n t e rnational Energy Agency (IEA, Paris) have continued tos e rve as the frame for collaborations to pool expertise andjoint scientific interests. Bilateral or multilateral agreements forcollaborations between European and non-European labora-tories have also been concluded.

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I n d u s t ry has been instrumental in helping to build devices and todevelop the technologies needed in fusion R&D; however, industryhas benefited from this relationship by developing commercial pro-ducts in various areas including gaseous discharges, plasma pro c e s-sing, surface treatment, lighting, plasma displays, vacuum technolo-g y, power electronics and even metallurgy or "renewable energ y "R&D, e.g.: • Power electronics is now being used in most modern electric loco-motives: this technology transfer has been triggered by a re q u e s tmade by the JET Project for high-power, high-frequency electro n i cc o n v e rt e r s .

• The world's shortest (180 m) steel rolling mill is in Cremona (I).E n e rg y - e fficient and friendly to the environment, it uses a new InlineStrip Production (ISP) process established on the basis of computermodels developed at Frascati (I) to study magnetic field effects onfusion reactor materials.

• A new CO2 laser-based anemometer, which allows wind turbinesto work under extended weather conditions, is an unexpected spin-o ff from fusion plasma physics re s e a rch: physicists at Risø (DK)developed the laser method for advanced measurements in fusionp l a s m a s .

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ASSOCIATION EURATOM/ÖAWÖsterreischische Akademie derWissenschaftenTechnische Universitaet Wien Institut fuerAllgemeine PhysikWiedner Hauptstrasse 8-12/134A-1040 WIEN-Austria

ASSOCIATION EURATOM/Etat Belge(ERM/KMS)Ecole Royale Militaire/Koninklijke MilitaireSchool -Laboratoire de Physique desPlasmas/Laboratorium voor PlasmafysicaAssociation "Euratom-Etat belge"/Associatie"Euratom-Belgische Staat"avenue de la Renaissance 30B-1040 Brussels - Belgium

ASSOCIATION EURATOM/Etat Belge (ULB)

Physique Statistique, Plasmas et Optique Université Libre de Bruxelles Campus de la Plaine 231Boulevard du TriompheB-1050 Bruxelles - Belgium

ASSOCIATION EURATOM/Etat Belge(SCK.CEN) SCK.CENBoeretang 200B-2400 Mol - Belgium

ASSOCIATION EURATOM/RISØ Risø National LaboratoryFusion Research UnitOFD – 128 .O. Box 49K-4000 Roskilde - Denmark

ASSOCIATION EURATOM/TEKESTechnology Development Centre Finland(TEKES)P.O. Box 69 FIN-00101 Helsinki - Finland

VTT Energy/Nuclear EnergyTekniikantie, 4 C, EspooP.O. Box 1604FIN-02044 VTT - Finland

ASSOCIATION EURATOM/CEADépartement de Recherches sur la FusionContrôlée Centre d'Etudes de CadaracheBoîte Postale 1F-13108 Saint-Paul-lez-Durance - France

ASSOCIATION EURATOM/IPPMax-Planck-Institut für PlasmaphysikBoltzmannstrasse 2D-85748 Garching bei München - Germany

ASSOCIATION EURATOM/FZJ"Institut für Plasmaphysik" and "Projekt Kernfusion"Partner in the Trilateral Euregio Cluster (TEC)Forschungszentrum Jülich (FZJ)D-52425 Jülich - Germany

ASSOCIATION EURATOM/FZKForschungszentrum Karlsruhe (FZK) GmbHNuclear Fusion ProjectP.O. Box 3640D-76021 Karlsruhe - Germany

EURATOM/GREECE - Laboratories

- National Technical UniversityDepartment of Electrical & ComputerEngineering42 Patission Street, Athens - Greece

- National Centre for Scientific Research"Demokritos"Institute of Nuclear Technology-RadiationProtectionPO Box 60228 Aghia Paraskevi, Athens -Greece

ASSOCIATION EURATOM/ENEACentro Ricerche EnergiaENEAVia E. Fermi 27I-00044 Frascati - Italy

ASSOCIATION EURATOM/ENEAIstituto di Fisica del Plasma “Piero Caldirola”Associazione Euratom/ENEA/CNRVia R. Cozzi 53I-20125 Milano - Italy

European Fusion Associations

EFDA - European Fusion Development Agreement

EFDA European Fusion Development AgreementMax-Planck-Institut für PlasmaphysikBoltzmannstrasse 2D-85748 Garching bei München - Germany

EURATOM/ENEAIstituto Gas IonizzatiConsiglio Nazionale della RicercheCorso Stati Uniti 4I-35020-CAMIN PADOVA - Italy

ASSOCIATION EURATOM/DCUDublin City University School of PhysicalSciencesGlasnevin EI-DUBLIN 9 - IrelandASSOCIATION EURATOM/FOMFOM-Instituut voor Plasmafysica "Rijnhuizen"Edisonbaan 14NL-3439 MN Nieuwegein - Netherlands

ASSOCIATION EURATOM/FOMNetherlands Energy Research Foundation ECNBusiness Unit ECN-Nuclear EnergyP.O. Box 1NL-1755 ZG PETTEN - Netherlands

ASSOCIATION EURATOM/ISTCentro de Fusao NuclearInstituto Superior TecnicoP-1096 LISBOA Codex - Portugal

ASSOCIATION EURATOM-CIEMATCIEMAT (Centro de InvestigacionesEnergéticas, Medioambientales yTecnologicas)avenida Complutense 22E-28040 Madrid - Spain

Association EURATOM - Confédération SuisseCentre de Recherches en Physique des PlasmasEcole Polytechnique Fédérale de LausanneBàtiment PPBCH - 1015 LausanneS w i t z e r l a n d

ASSOCIATION EURATOM/NFRRoyal Institute of TechnologyPlasma Physics and Fusion ResearchTechnical Ring 31S-10044 Stockholm 70 - Sweden

ASSOCIATION EURATOM/UKAEAUKAEA FusionCulham, Abingdon Oxon OX14 3DB - United Kingdom

ASSOCIATION EURATOM - IPP.CRInstitute of Plasma Physics Associationof Sciences of the Czech RepublicZa Slovankov, 3P.O. Box 17CZ- 182 21 Praha 8 - Czech Republic

ASSOCIATION EURATOM - HASHungarian Academy of SciencesNàdor u. 7H-1051 HUNGARY

ASSOCIATION EURATOM - NASTINational Agency for Science Technology andInnovation21-25 Mendeleev Str.RO-70168, Sector 1 Bucharest - Romania