Nuclear fusion has the potential of becoming a practically inexhaustible and almost clean energy source. The world’s efforts, in which Italy and Europe play a major role, focus on the confinement of a burning D-T plasma in devices based on superconducting magnets: the multi-billion ITER project, under construction at Cadarache in France, a few hundred kilometres from Torino, is scheduled to start operating in the late 20’s, while the EU is strongly pursuing the next step, i.e. a DEMO program, aiming at providing the first kWh from fusion. This course gives an introduction to both the physics and the engineering of a nuclear fusion reactor of tokamak type. Some emphasis is put on the modelling aspects, at both the component and system level. The course, mandatory for nuclear engineering students, could also be of interest for students who simply desire to get a somewhat more precise idea of the enormous potential of the fusion energy source.

The student should acquire a basic knowledge of the physics of magnetically confined plasmas in a tokamak-type fusion reactor, from an engineering point of view, as well as of the structure and functions of the main reactor components and of their integration in a consistent design. The student should also acquire a critical perception of the main open issues and related perspectives of research and development in the field of fusion technology.

The essential pre-requisite of the course is a good knowledge of the topics presented in the first two years of any Engineering BSc program. An introduction to nuclear engineering (like that provided, e.g., in the course “Fondamenti di ingegneria nucleare”) could be helpful, but is not mandatory.

- Nuclear fusion in a nutshell - The European roadmap on fusion electricity - The course roadmap - The key parameters and constraints for a 1 GWe fusion reactor of tokamak type: - tau_E~ 1 s  plasma confinement: * motion of a single charged particle in the electromagnetic field * definition of a plasma: Debye length, plasma frequency, quasi-neutrality * MHD equilibrium and stability * collisions in a plasma * particle and energy transport * performance of present tokamaks vs future reactors # the superconducting magnet system and its cryogenics. - T ~ 10-20 keV  plasma heating: * Ohmic; need for auxiliary heating (NNBI, RF); alpha. - n ~ 1020-1021 m-3  plasma fueling: # the fuel cycle  the blanket (part 1)  neutronics, choice of breeder/multiplier  ITER TBM vs EU DEMO BB # vacuum technology. - limitations on heat flux q (MW/m2), and core plasma contamination (Z_eff)  plasma-wall interactions: * Debye sheath and Bohm criterion; impurities; Scrape-Off Layer, 2-point model # limiter, first wall, divertor; engineering of power exhaust. - Practical experience of small tokamak plasma operation (GOLEM) - Power extraction and conversion  the blanket (part 2)  choice of coolant; storage; BoP - Wrap-up # ubiquitous/enabling technologies - materials ( DONES/IFMIF) - safety. # ITER and satellites schedule; the current status of the EU DEMO design.

Physics The course will consist of theoretical lectures and of the practical solution of simple numerical problems. The students will also have the opportunity to perform an experimental session on a small tokamak. Engineering The course will consist of theoretical lectures and of the demonstration of dedicated software on a few specific topics (superconducting magnets, breeding blanket and power exhaust) to the students, who will also have the opportunity to use it.

Physics Reference textbooks • J.P. Freidberg, Plasma Physics and Fusion Energy, Cambridge University Press, 2007 • Peter C. Stangeby, The Plasma Boundary of Magnetic Fusion Devices, Institute of Physics Publishing, 2000 Auxiliary books • C. Wendell Horton, Jr. and S. Benkadda, ITER Physics, World Scientific, 2015. Engineering A few good references are available, see e.g. • Thomas J. Dolan (Editor), “Magnetic Fusion Technology (Lecture Notes in Energy)”, Springer; 2013 edition (February 10, 2014), ISBN 978-1447155553 • Weston M. Stacey, “Fusion: An Introduction to the Physics and Technology of Magnetic Confinement Fusion” 2nd Edition, Wiley-VCH (March 22, 2010), ISBN 978-3527409679. However, no single textbook really covers the scope of topics to the needed depth for this course. We shall therefore often rely on presentations from summer schools (e.g. the KIT International School on Fusion Technologies http://summerschool.fusion.kit.edu/ ) and on presentations given at international conferences, as well as on papers published on international journals like Fusion Engineering and Design, Fusion Science and Technology, etc.

... The exams for the two parts are separate. The final score will be the average of the two. Physics The final exam is in two parts, the first (mandatory) is written, the second is an oral discussion. The written test, of duration about 1.5 h, involves a number of numerical problems and theoretical questions. It aims at verifying that the student can (i) complete successfully some simple calculations, and (ii) can critically discuss the simplest phenomena occurring in a fusion reactor. The students will be allowed to use a pocket computer, but no another material will be allowed, except what provided by the instructor. The maximum score which can be obtained from the written test is 27/30. Students who obtained a score equal or higher than 26/30 in the written test may ask to also have an oral discussion, during which the level of comprehension of the physical processes discussed during the main lectures will be verified in depth. Engineering For all students, an oral exam about the different topics treated in the course, will lead to a maximum mark of 24/30. For those students who aim at a maximum mark above 24/30, the oral will be followed by a presentation (in ppt form), of the estimated duration of ~ 10 minutes, on the results of a small project, based on the application of the software presented in class, in either of the following three fields at the students’ choice: 1) superconducting magnets; 2) breeding blanket; 3) power exhaust. The presentation will be valued up to an additional 6 points and will be considered for a possible final mark of 30 cum laude.

Gli studenti e le studentesse con disabilità o con Disturbi Specifici di Apprendimento (DSA), oltre alla segnalazione tramite procedura informatizzata, sono invitati a comunicare anche direttamente al/la docente titolare dell'insegnamento, con un preavviso non inferiore ad una settimana dall'avvio della sessione d'esame, gli strumenti compensativi concordati con l'Unità Special Needs, al fine di permettere al/la docente la declinazione più idonea in riferimento alla specifica tipologia di esame.