JET JOINT UNDERTAKING : Annual Report 1998
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Plasma-Materials and Divertor Options for Fusion
Plasma-Materials and Divertor Options for Fusion Presented to: National Academy of Sciences Panel A Strategic Plan for U.S. Burning Plasma Research J. Rapp ORNL is managed by UT-Battelle for the US Department of Energy Lifetime of divertor will deterimine fusion reactor availability TF coils Coolant manifold (permanent) Upper ports (modules and coolant) Blanket Cost of modules electricity is 5-6 yrs lifetime proportional 0.6 to (1/A) Central ports (modules) Vacuum vessel 70cm Cool shield (permanent) 30cm Divertor plates (permanent) Lower ports 2 yrs lifetime goal (divertor) Main driver of scheduled maintenance: divertor (and blanket) 2 Juergen Rapp Outline • Plasma-Material Interaction (PMI) challenges • Potential Plasma-Facing Materials (PFMs) and Components (PFCs) • Current status of U.S. PMI research • Facilities needed for the development of PFCs • Strategic elements to accelerate U.S. burning plasma research • A proposed high-level R&D program and roadmap for PMI 3 Juergen Rapp Outline • Plasma-Material Interaction (PMI) challenges • Potential Plasma-Facing Materials (PFMs) and Components (PFCs) • Current status of U.S. PMI research • Facilities needed for the development of PFCs • Strategic elements to accelerate U.S. burning plasma research • A proposed high-level R&D program and roadmap for PMI 4 Juergen Rapp Challenges for materials: fluxes and fluence, temperatures JET ITER FNSF Fusion Reactor 50 x divertor ion fluxes 5000 x divertor ion fluence up to 5 x ion fluence 106 x neutron fluence (1dpa) up to 100 x neutron fluence (150dpa) -
A European Success Story the Joint European Torus
EFDA JET JETJETJET LEAD ING DEVICE FOR FUSION STUDIES HOLDER OF THE WORLD RECORD OF FUSION POWER PRODUCTION EXPERIMENTS STRONGLY FOCUSSED ON THE PREPARATION FOR ITER EXPERIMENTAL DEVICE USED UNDER THE EUROPEAN FUSION DEVELOPEMENT AGREEMENT THE JOINT EUROPEAN TORUS A EUROPEAN SUCCESS STORY EFDA Fusion: the Energy of the Sun If the temperature of a gas is raised above 10,000 °C virtually all of the atoms become ionised and electrons separate from their nuclei. The result is a complete mix of electrons and ions with the sum of all charges being very close to zero as only small charge imbalance is allowed. Thus, the ionised gas remains almost neutral throughout. This constitutes a fourth state of matter called plasma, with a wide range of unique features. D Deuterium 3He Helium 3 The sun, and similar stars, are sphe- Fusion D T Tritium res of plasma composed mainly of Li Lithium hydrogen. The high temperature, 4He Helium 4 3He Energy U Uranium around 15 million °C, is necessary released for the pressure of the plasma to in Fusion T balance the inward gravitational for- ces. Under these conditions it is pos- Li Fission sible for hydrogen nuclei to fuse together and release energy. Nuclear binding energy In a terrestrial system the aim is to 4He U produce the ‘easiest’ fusion reaction Energy released using deuterium and tritium. Even in fission then the rate of fusion reactions becomes large enough only at high JG97.362/4c Atomic mass particle energy. Therefore, when the Dn required nuclear reactions result from the thermal motions of the nuclei, so-called thermonuclear fusion, it is necessary to achieve u • extremely high temperatures, of at least 100 million °C. -
Steady State and Transient Power Handling in JET G.F.Matthews* on Behalf of the JET EFDA Exhaust Physics Task Force and JET EFDA Contributors+ +See Annex of J
Steady State and Transient Power Handling in JET G.F.Matthews* on behalf of the JET EFDA Exhaust Physics Task Force and JET EFDA Contributors+ +See annex of J. Pamela et al, "Overview of JET Results", Fusion Energy 2002 (Proc. 19th Int. Conf. Lyon, 2002),IAEA, Vienna. *Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxon. OX14 3DB,UK. E-mail: [email protected] Abstract. Steady state and transient power deposition profiles have been measured in the JET MIIGB divertor using improved diagnostics techniques involving the use of fast infra-red, thermocouples and Langmuir probe arrays. In unfuelled type I ELMy H-modes a very narrow power profile is observed at the outer target which we associate with the ion channel. Systematic parameter scans have been carried out and our analysis shows that the average power width scaling is consistent with a classical dependence of perpendicular transport in the SOL. Using the fast IR capability the factors such as rise time, broadening, variability and in/out asymmetry have been studied and lead to the conclusion that type I ELMs in ITER may fall just below the material ablation limits. JET disruptions are very different from type I ELMs in that only a small fraction of the thermal energy reaches the divertor and what does arrive is distributed uniformly over the divertor area. This is very different from the current ITER assumption which puts most of the energy from the thermal quench onto the divertor strike points. 1. Introduction The actively cooled divertor target for ITER has been tested up to a surface power loading of 25MWm-2 but the planned operating point is around 10MWm-2 to allow for excursions. -
Fusion: the Way Ahead
Fusion: the way ahead Feature: Physics World March 2006 pages 20 - 26 The recent decision to build the world's largest fusion experiment - ITER - in France has thrown down the gauntlet to fusion researchers worldwide. Richard Pitts, Richard Buttery and Simon Pinches describe how the Joint European Torus in the UK is playing a key role in ensuring ITER will demonstrate the reality of fusion power At a Glance: Fusion power • Fusion is the process whereby two light nuclei bind to form a heavier nucleus with the release of energy • Harnessing fusion on Earth via deuterium and tritium reactions would lead to an environmentally friendly and almost limitless energy source • One promising route to fusion power is to magnetically confine a hot, dense plasma inside a doughnut-shaped device called a tokamak • The JET tokamak provides a vital testing ground for understanding the physics and technologies necessary for an eventual fusion reactor • ITER is due to power up in 2016 and will be the next step towards a demonstration fusion power plant, which could be operational by 2035 By 2025 the Earth's population is predicted to reach eight billion. By the turn of the next century it could be as many as 12 billion. Even if the industrialized nations find a way to reduce their energy consumption, this unprecedented increase in population - coupled with rising prosperity in the developing world - will place huge demands on global energy supplies. As our primary sources of energy - fossil fuels - begin to run out, and burning them causes increasing environmental concerns, the human race faces the challenge of finding new energy sources. -
DISTRIBUTION of THIS DOCUMENT IS UNLIMITED Temperatures in the Range 5-10 Kev Are Still Needed, but the Lawson Number Can Be Reduced to the Low 10 Cm Sec Range
TFTR and Other Large Tokamaks Plasma Physics Laboratory, Princeton University Princeton, New Jersey 08544 H.P. Furth CONF-8604223—1 DE86 012761 Introduction The near-term goal of fusion research is to produce deuterium-tritium plasmas with temperatures above 10 keV and Lawson numbers nTE above 10 cm sec. As indicated in Fig. 1, experiments entering this parameter range will be able to satisfy Lawson's break-even criterion, where the fusion power output equals the required plasma-heating-power input (Q = 1 ). The ultimate reactor goal is to reach equilibrium-burn conditions, where the energetic alpha particles generated by the D-T reaction are sufficient to maintain the plasma temperature against all heat losses (Q = °°). At the outset of the international controlled-fusion research effort in the 19 50's, Lawson's goal seemed intimidatingly remote from experimental capabilities. During the following ten years, substantial scientific progress was made, but the rate of advance in the Lawson diagram was not such as to inspire confidence that the fusion program would reach fruition within the lifetime of its pioneers. The notable success of the Kurchatov Institute's T-3 tokamak during 1968-69 brightened the outlook considerably. The tokamak configuration was recognized as a cost-effective experimental tool and has permitted steady progress during subsequent decades. World-wide recognition of the favorable experimental opportunity for entry into the reactor plasma regime led to the initiation, in the mid-1970's, of four large new tokamak projects (Table I). Plans for the Joint European Torus (JET) were defined in 1971-73: th_ very large plasma size and high current of the JET plasma offered a potential for exceeding the Lawson break- even criterion and possibly evan reaching ignition in D-T plasmas. -
The Pumped Divertor the NEW PHASE of JET B.E
The Pumped Divertor THE NEW PHASE OF JET B.E. Keen and M.L. Watkins and the JET Team JET Joint Undertaking, Abingdon, Oxford, UK Associate Member of EPS The pumped divertor experiment, in demonstrating before full deuterium-tritium operation an effective method of impurity control, aims to provide essential design data for a Next Step tokamak fusion device. The basic principle of the fusion pro Switzerland and Sweden. By mid-1983, by careful design of the targets and speci cess is the fusing of light nuclei to form the construction of JET, its power supplies fic operational techniques, but is limited, heavier ones and the accompanying re and buildings were completed on sche ultimately, by an unacceptably high influx lease of substantial energy. For a fusion dule and broadly to budget and the prog of impurities. The fourth area of work had reactor, there are several possible fusion ramme started. been started by earlier studies of energetic reactions, but the one that is easiest to JET is the largest project in the coordi particles produced as fusion products or achieve is that between the deuterium and nated programme of EURATOM, whose by ion cyclotron resonance heating tritium isotopes of hydrogen. This D-T fusion programme is designed to lead ulti (ICRH). It has now been addressed further reaction is : mately to the construction of an energy by the first tokamak plasma experiments D + T → 4He + neutrons + 17.6 MeV. producing reactor. Its strategy is based on in D-T mixtures. These results are presen At the temperatures needed for this reac the sequential construction of major ap ted briefly in the following sections. -
Corrosion Issues in Fusion Reactors
Corrosion Issues in Fusion Reactors Digby D. Macdonald1 and George R. Engelhardt2 1Department of Nuclear Engineering University of California at Berkeley Berkeley, CA 94720 2OLI Systems, Inc. 240 Cedar Knolls Rd Cedar Knolls, NJ 07927 WCO Forum Corrosion 2020 Houston, TX, USA Background • Nuclear fusion is the process of fusing the light elements (primarily 1 2 3 the isotopes of hydrogen, H1, D1, T1. • Fusion results in a loss of mass, which is converted into energy, E = Δm.c2. • Process that occurs in the sun and stars in nuclear synthesis. Minimum temperature for D + T is 10 keV = 300,000,000 oC equivalent. • First demonstrated on earth in 1950s through thermonuclear weapons. • Almost a limitless source of clean energy if it can be made to work. • First controlled fusion demonstrated at JET in Oxford, UK, Q =0.75. • First technology demonstration, ITER (‘the way”), being constructed at Cadarache, France. Q > 10. Thermonuclear Reactions Reaction Reaction Equation Initial Mass (u) Mass Change (u) % Mass Change 2 2 3 1 -3 D-D D1 + D1 → He2 + n0 4.027106424 -2.44152x10 0.06062 2 2 3 1 -3 D-D D1 + D1 → H1 + p1 4.027106424 -3.780754x10 0.09388 2 3 4 1 D-T D1 + T1 → He2 + n0 5.029602412 -0.019427508 0.3863 e--p+ e- + p+ → 2hν 1.8219x10-31 -1.8219x10-31 100 Must overcome Coulombic repulsion of nuclei in the plasma Preferred Reaction • The easiest reaction to achieve 2 3 4 1 is: D1 + T1 → He2 + n0 because it has the lowest ignition temperature (10 keV). -
Lyra' Divertor
ENERGY AND PARTICLE CONTROL CHARACTERISTICS OF THE ASDEX UPGRADE `LYRA' DIVERTOR M. Kaufmann, H-S. Bosch, A. Herrmann, A. Kallenbach, K. Borrass, A. Carlson, D. Coster, J.C. Fuchs, J. Gafert, K. Lackner, J. Neuhauser, R. Schneider, J. Schweinzer, W. Suttrop, W. Ullrich, U. Wenzel, and ASDEX Upgrade team Max-Planck-Institut fÈurPlasmaphysik, EURATOM-IPP Association, Garching und Berlin, Germany Abstract In 1997 the new `LYRA' divertor went into operation at ASDEX Upgrade and the neutral beam heating power was increased to 20 MW by installation of a second injector. This leads to the relatively high value of P/R of 12 MW/m. It has been shown that the ASDEX Upgrade LYRA divertor is capable of handling such high heating powers. Mea- surements presented in this paper reveal a reduction of the maximum heat ¯ux in the LYRA divertor by more than a factor of two compared to the open Divertor I. This reduction is caused by radiative losses inside the divertor region. Carbon radiation cools the divertor plasma down to a few eV where hydrogen radiation losses become signi®cant. They are increased due to an effective re¯ection of neutrals into the hot separatrix region. B2-Eirene modelling of the performed experiments supports the experimental ®ndings and re®nes the understanding of loss processes in the divertor region. 1. INTRODUCTION The width of the scrape-off layer (SOL) does not necessarily increase in proportion to the size of the device. This poses severe problems for the power exhaust in a fusion reactor. If we take ITER as described in the ®nal design report (FDR) [1], a power ¯ow across the separatrix in the order of 100 to 150 MW might be needed to stay in the H-mode [2]. -
June 2018 Fusion in Europe
FUSION IN EUROPE NEWS & VIEWS ON THE PROGRESS OF FUSION RESEARCH “Let us face it: TO DTT OR NOT TO DTT there is no VACUUM – HOW NOTHING REALLY planet B!” MATTERS NOW IS THE TIME TO BE AT JET 2 2018 Fusion Writers … wanted! … and Artists This could be you Fusion in Europe is call- ing for aspiring writers and gifted artists! Introduce yourself to an international audience! Catch one of our topics and turn it into your own! • The future powered by fusion energy • Fusion science and industrial reality • Fusion - a melting pot of different sciences • Fusion drives innovation Find the entire list here: tinyurl.com/ybd4omz7 Your application should include a short CV and a motivational letter. Please apply here: tinyurl.com/ybd4omz7 EUROfusion | Communications Team | Anne Purschwitz (”Fusion in Europe“ Editor) Boltzmannstr. 2 | 85748Application Garching | +49 89 deadline: 3299 4128 | [email protected] 25 June 2018 | Editorial | EUROfusion | “It is the best time to be at JET right now” says a passionate Eva Belo nohy. The member of JET’s Exploitation Unit has recently organised a very suc- cessful workshop. It was aimed to ‘refresh’ the knowledge of European fu- sion researchers regarding the Joint European Torus (JET) but that was a classic understatement. The meeting was a fully-fledged overview on JET’s capabilities which have tremendously changed in the past. The tokamak has gone through major upgrades since it saw its first deuterium tritium campaign in 1997. Those include not only an ITER-like wall but also an Fusion Writers… wanted! … increase of the heating power by 50 percent. -
Coupling Optimization Experiment on HL-2A Based on Passive-Active Multijunction Antenna for 3.7Ghz Lower Hybrid System
42nd EPS Conference on Plasma Physics P5.137 Coupling optimization experiment on HL-2A based on Passive-Active Multijunction antenna for 3.7GHz Lower Hybrid system Xingyu Bai, Hao Zeng, Bo Lu, Xiaolan Zou1, Roland Magne1, Annika Ekedahl1, Julien Hillairet1, Chao Wang, Jun Liang, He Wang, Yali Chen, Junwei He, Jieqiong Wang, Kun Feng and Jun Rao Southwestern Institute of Physics, Chengdu, China 1 CEA, IRFM, 13108 Saint Paul-lez-Durance, France System Introduction. A new Lower Hybrid Wave (LHW) system (3.7GHz/2MW/2s) has been built on HL-2A tokamak. A Passive-Active-Multijunction (PAM) concept antenna [1], [2] was designed and built, fed by 500kW × 4 TH2103A Klystrons, delivering ITER-relevant power density, i.e. 25MW/m2 at f = 3.7GHz [3],[4]. The antenna is designed to launch a peak parallel refractive index of N||=2.75 with a low theoretical Reflection Coefficient (RC), i.e. less than 1% [5], [6]. A specific gas puffing system for improving the antenna coupling and a set of Langmuir probes for antenna mouth density measurements are separately located on one side of the antenna each. An auxiliary vacuum system is installed at the rear of the antenna to improve the pumping efficiency. Vacuum leak tests and low power microwave scattering parameter measurements were done before the PAM antenna was installed on HL-2A, allowing the antenna to be conditioned at RF power of 100kW/100ms before starting plasma operation. Fig. 1: New LHW system(3.7GHz/2MW/2s)of HL- Fig. 2: PAM launcher was developed and installed, facing 2A. -
Physics Basis for the ITER Tungsten Divertor
Physics basis for the ITER tungsten divertor R. A. Pitts1, X. Bonnin1, F. Escourbiac1, T. Hirai1, J. P. Gunn2, A. S. Kukushkin3, M. Lehnen1, V. Rozhansky4, E. Sytova1,4, G. De Temmerman1 1 ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St Paul Lez Durance Cedex, France 2CEA Cadarache, F-13108 St Paul lez Durance, France 3NRC Kurchatov Institute, 123182 Moscow, Russia 4 Peter the Great St.Petersburg Polytechnic University St.Petersburg, 195251 St.Petersburg, Russia [email protected] Building on about 20 years of physics simulation, engineering design and component testing, the ITER tokamak divertor is the largest and most complex ever to be constructed. At the time of the last report to the PSI Conference Series on the ITER divertor status in 2012, the strategy to begin operations with full-tungsten (W) armour had been proposed by the ITER Organization (IO) and was under study. The decision was taken formally in 2013, since when the physics basis in support of the final design has been further developed, with invaluable and numerous contributions from the research community within the ITER Parties. On the eve of component procurement, this paper will discuss the present basis, beginning with a reminder of the key elements defining the overall design, and outlining relevant aspects of the Research Plan accompanying the new “4-staged approach” to ITER nuclear operations which fix the overall lifetime constraint of the first divertor. The main focus will be on steady state and transient power fluxes in both non-active and DT phases, the main drivers for design and future divertor operation. -
Introduction to Nuclear Fusion
Introduction to Nuclear Fusion Prof. Dr. Yong-Su Na To build a sun on earth - Open magnetic confinement - Closed magnetic confinement 2 What is closed magnetic confinement? 3 Open Magnetic System B sin 2 min Bmax v|| loss cone loss cone - Suffering from end losses J.P. Freidberg, “Ideal Magneto-Hydro-Dynamics”, lecture note A. A. Harms et al, “Principles of Fusion Energy”, World Scientific (2000) 4 Open Magnetic System Magnetic field Is this motion realistic? ion Dunkin donuts (2010) 5 Closed Magnetic System Magnetic field Donut-shaped vacuum vessel ion 6 Closed Magnetic System 7 Closed Magnetic System Magnetic field R 0 a Plasma needs to be confined ion R0 = 1.8 m, a = 0.5 m in KSTAR 8 Closed Magnetic System Magnetic field R 0 a Plasma needs to be confined ion R0 = 6.2 m, a = 2.0 m in ITER 9 Closed Magnetic System Toroidal Field (TF) coil Magnetic field Toroidal direction Applying toroidal magnetic field ion 3.5 T in KSTAR, 5.3 T in ITER 10 Closed Magnetic System Toroidal Field (TF) coil Toroidal direction Applying toroidal magnetic field 3.5 T in KSTAR, 5.3 T in ITER 11 Closed Magnetic System Toroidal Field (TF) coil Magnetic field Toroidal direction Magnetic field of earth? 0.5 Gauss = 0.00005 T ion 12 http://www.crystalinks.com/earthsmagneticfield.html Closed Magnetic System Magnetic field Magnetic field of earth? 0.5 Gauss = 0.00005 T ion http://www.transformacionconciencia.com/archives/2384 13 Closed Magnetic System Magnetic field ion 14 Lesch, Astrophysics, IPP Summer School (2008) Closed Magnetic System Magnetic field ion electron