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 of a nuclear fusion reactor. 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.
Nuclear fusion has the potential of becoming a practically inexhaustible, carbon-free and environmentally friendly energy source. The world’s efforts, in which Italy and Europe play a leading 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 the physics of a nuclear fusion reactor. 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 fusion reactor. 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 science and technology.
The student should acquire a basic knowledge of the physics of a magnetic fusion reactor. After the course, they should be able to:
- Sketch the energy, mass and momentum balance for a fusion reactor
- Understand the general properties of matter in the state of plasma, and know what additional peculiarities characterize plasma in a fusion environment
- Understand the basic mechanisms of magnetic plasma confinement (both from the single particle orbit theory point of view and using the collective fluid description)
- Understand the properties of mechanical equilibrium in a magnetically confined plasma
- Understand the main mechanisms governing interaction with the fusion plasma and the external world
- Understand the basic physics of particles and power exhaust in a fusion reactor and their critical importance for the overall machine
For all the topics mentioned above, the students should also be able to produce simple numerical estimates, and to start proficient interaction with the relevant scientific community in case he/she develops interest for the subject.
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.
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 “Elementi di ingegneria nucleare”) could be helpful, but is not mandatory.
* General introduction
* 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
* plasma heating
* Debye sheath and Bohm criterion; impurities; Scrape-Off Layer, 2-point model
* Physics of power exhaust
* Impurities physics
* Practical experience of small tokamak plasma operation (GOLEM)
* General introduction
* Estimate of the parameters characterizing a possible fusion reactor
* definition of a plasma: Debye length, plasma frequency, quasi-neutrality
* motion of a single charged particle in the electromagnetic field
* MHD equilibrium and stability
* collisions in a plasma
* particle and energy transport
* performance of present tokamaks vs future reactors
* plasma heating
* Debye sheath and Bohm criterion; impurities; Scrape-Off Layer, 2-point model
* Physics of power exhaust
* Impurities physics
* Practical experience of small tokamak plasma operation (GOLEM)
The teacher will try to organize a limited number of lectures/seminars given by external experts on selected topics. The detailed schedule and subject of these contributions will depend on the availability of the potential contributors. The teacher will broadcast complete information during the lecturing term as soon as possible.
The teacher will try to organize a limited number of lectures/seminars given by external experts on selected topics. The detailed schedule and subject of these contributions will depend on the availability of the potential contributors. The teacher will broadcast complete information during the lecturing term as soon as possible.
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.
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 GOLEM, a small tokamak operated in collaboration with the Czech Technical University in Prague.
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
The teacher will also distribute a few notes in support to the reference textbooks.
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
The teacher will also distribute a few notes in support to the reference textbooks.
Modalità di esame: Prova scritta (in aula); Prova orale facoltativa; Elaborato scritto individuale;
Exam: Written test; Optional oral exam; Individual essay;
...
The final exam is in two parts, the first (mandatory) is written, the second is an oral discussion. The written test, of duration about 1h 40 m, 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.
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.
Exam: Written test; Optional oral exam; Individual essay;
The final grade is a combination of different contributions, as detailed in the following.
Part 1
The candidate will deliver a written report on the GOLEM experience. This report will receive a score S_a ranging from 0 to 30.
The candidate will deliver a written test (held during the official exam calls). The test lasts 1h 40m, and is composed by three questions. The three questions can be:
Open questions on topics discussed during the lectures.
Numerical problems designed to test the capacity of the student to assess important aspects of the physics of a fusion reactor (as a non-exhaustive example list: evaluation of critical plasma parameters in a fusion reactor, estimate of the forces involved in a reactor mechanical equilibrium, energy fluxes and requirements for the power exhaust system).
A sketchy derivation of some of the results discussed during the lectures.
This test will receive a score S_b ranging from 0 to 30.
Once the first two assignments are completed, the first part can be finally evaluated. The score associated with Part 1 will be:
S_1=min(27,74/80 S_a+6/80 S_a )
(The weights in the sum are taken based on the number of hours devoted to the GOLEM experience and the total number of hours to the whole subject)
Part 2
After the first score S_1 is available, the following options are available:
If S_1≤25, this will also be the final score (i.e. there will be no further step)
If S_1≥26 the candidate will be required to choose one of the following options:
To consolidate the score received “as it is”. In this case the final score will coincide with S_1.
To also sustain an oral discussion. In this case, after the discussion the final score will be S_1+∆, with ∆ ranging from -5 to 5 (30 “cum Laude” will correspond to the case S_1+∆ >30)
Remark: After a candidate expressed her/his preference about sustaining or not an oral discussion, she/he will not be allowed to modify this choice later.
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.
Modalità di esame: Prova orale facoltativa; Prova scritta su carta con videosorveglianza dei docenti; Elaborato progettuale in gruppo;
The general layout in case for the online exam is the same as for onsite exam.
In addition to this, for the written test the following modifications should be considered:
(i) The teacher will supervise the written test with a Virtual Classroom.
(ii) The teacher will broadcast the exam test assignment by inserting the material in a dedicated dropbox folder (common for all students).
(iii) The students will be asked to deliver their work by uploading it in a second dedicated dropbox folder (each student will have his/her own folder)
(iv) During the exam, there will be the possibility to have a chat between the teacher and the students.
(v) The oral discussion will be held by means of a suitable meeting platform (zoom, google meet, skype, virtual classroom, etc...).
Exam: Optional oral exam; Paper-based written test with video surveillance of the teaching staff; Group project;
In case of online exam the same grading criteria as for the in person test apply, with the following modifications:
- For the written test the teacher will create a dedicate Virtual Classroom he will use to communicate with candidates (chat) during the exam and to monitor the candidates by checking their webcams (which will be required to stay open). As a backup communication tool, the day before the exam the teacher will create a dedicated telegram group and distribute the invitation link to the candidates.
Also, the teacher will provide a dedicated cloud folder shared with the students to facilitate distributing the exam test and collecting the candidates work. This will be created the day before the exam at the latest, and proper indication on how to access it will be distributed.
- For the oral test, the candidates and the examination board will agree on a remote meeting tool. Microsoft teams will be preferred, but others might be selected if necessary. The oral discussion will be recorded.
Modalità di esame: Prova scritta (in aula); Prova orale facoltativa; Prova scritta tramite PC con l'utilizzo della piattaforma di ateneo; Elaborato progettuale in gruppo;
In case a blended exam is organized, both the written test and the oral discussion can be either onsite or online. The descriptions provided in the relevant sections will apply.
Exam: Written test; Optional oral exam; Computer-based written test using the PoliTo platform; Group project;
In case of online exam the same grading criteria as for the in person test apply, with the following modifications:
the candidates available in person will follow the traditional procedure, for those available online the procedure described above applies. Candidates will be required to inform the teacher if they intend to attend the exam in person or online, in order to allow the creation of the needed cloud folder and the distribution of the telegram invitation link.
