The student will acquire a basic knowledge of the structure and functions of the main reactor components, with special emphasis on the divertor, the blanket and the superconducting magnets, and of their integration in a consistent tokamak design. The student will also acquire a critical perception of the main open issues and related perspectives of research and development in the field of fusion technology. The students will also learn the fundamentals of the Modelica object-oriented programming language that, starting from the simple problems dealt with during the course, will potentially allow them to model the main plant systems at different complexity levels.

The essential pre-requisite is the course Nuclear Fusion Reactor Physics (or other introductory plasma/fusion physics course). It is also important to have a good knowledge of the topics presented in the first two years of any Engineering BSc program. Finally, an introduction to nuclear engineering (like that provided, e.g., in the course “Elementi di ingegneria nucleare” at Politecnico di Torino) could be helpful, but is not mandatory.

LECTURES The structure and performance of present and forthcoming (under construction) tokamaks vs. future nuclear fusion reactors. The European roadmap on fusion electricity. The course roadmap. The three fundamental challenges of fusion engineering: A. Managing the power and particle exhaust from the plasma, while controlling impurities at the same time o Power balance and plasma-surface interactions in tokamaks o The Scrape-Off Layer o Limiter, First Wall (FW), Divertor o Sputtering and the Lawson criterion with impurities o Heat transfer enhancement in high heat flux tokamak components o The divertor problem in DEMO perspective o The Liquid Metal Divertor (LMD) Auxiliary heating of the plasma: Neutral Beam Injection, … B. Extracting the power deposited in the blanket by the neutrons, while breeding the tritium fuel o The blanket and its main functions o Load conditions on FW/blanket o Tritium consumption and production (needs) o Choice of breeder/multiplier, coolant, structural material, and assessment of their compatibility o EU-DEMO Breeding Blanket (BB) designs: HCPB, WCLL o The ITER TBM program vs. the EU-DEMO BB o BB Maintenance and Balance of Plant (BoP) o Advanced BB concepts The Fusion Fuel Cycle: Vacuum Pumping, Tritium extraction, Matter Injection C. Confining a 108 K plasma using powerful superconducting (SC) magnets, while keeping them at 4.5 K o Introduction: The tokamak magnet system; Magnet electro-mechanics; Why SC magnets?; Superconductivity fundamentals; SC magnets; Cooling SC magnets. Cryogenics and thermophysical properties of materials at cryogenic conditions vs. RT; Current sharing temperature, stability, quench o Low-Tc vs. high-Tc superconductors o Winding a SC magnet: strands, cable-in-conduit conductors, coils and magnets o Modeling SC magnets: The 4C code. Introduction to the safety of nuclear fusion reactors. LABORATORY 0. Introduction to the Modelica language: fundamentals; the Modelica Standard Library; the ThermoPower library. 1. Simulation of the refill circuit of a possible Liquid Metal Divertor for the EU DEMO • Modelling the refill circuit with existing models (e.g. from the ThermoPower library) • Development of a model of an LMD target for the EU DEMO • Transient analysis of the LM refill circuit 2. Modelling the Breeding Blanket First Wall • Development of a Modelica model of the solid structure in the EU DEMO FW • Thermal-hydraulic model of the FW and its cooling channels • Analysis of the FW cooling under different heat loads 3. Modelling the cryogenic and superconducting magnet systems • Development of a Modelica model of a control valve • Development of a model of the CEA HELIOS facility • Dynamic simulation of the pulsed heat load smoothing in the HELIOS facility and comparison with experimental data

About 50/80 CFU will consist of theoretical lectures on the above-mentioned topics. The rest of the CFU will be devoted to a crash course on the Modelica computer language and to the script development for and application of simple Modelica models on the three key engineering challenges A-C above.

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 above-mentioned topics to the needed depth for this course. The instructor will therefore provide additional material in the form of slides used in class, as well as 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. On-line free guides of the Modelica language: https://www.modelica.org/modelicalanguage, Modelica By Examples (https://mbe.modelica.university/).

Exam: Written test; Compulsory oral exam;

The exam is in two parts: 1) The delivery of a brief written report on the application of the three above-mentioned Modelica scripts, developed during the course. This part can bring the student up to the 12/30 mark and it will confirm if the student has learned the fundamentals of the Modelica object-oriented programming language and if, starting from the simple problems dealt with during the course, she/he can model plant systems at different complexity levels; 2) An oral part, consisting of a discussion on the above-mentioned course topics, as actually developed during the lectures. This part can bring the student up to the 18/30 mark and it will confirm if the student has acquired a basic knowledge of the structure and functions of the main reactor components, with special emphasis on the divertor, the blanket and the superconducting magnets, and of their integration in a consistent tokamak design.

In addition to the message sent by the online system, students with disabilities or Specific Learning Disorders (SLD) are invited to directly inform the professor in charge of the course about the special arrangements for the exam that have been agreed with the Special Needs Unit. The professor has to be informed at least one week before the beginning of the examination session in order to provide students with the most suitable arrangements for each specific type of exam.