Centro di Ateneo “Centro Ricerche Fusione”
c/o Consorzio RFX

Tipo di tesi:Magistrale
Corso di Laurea:Ingegneria / Fisica
Tipologia:Sperimentale
Titolo della tesi:Analysis of lockeddynamicsinMAST-Upgrade/ JET / AUG
Relatore RFX:Lidia Piron
Relatore Accademico:LidiaPiron


Argomento della tesi:

ThisThesis aims at investigating the dynamics of locked mode behavior, a Magneto-Hydro-Dynamics instability, in plasmas performed
I) IntheMAST-Upgradedevice, at CCFE, Culham, UK,when exploringa wide range of operational parameters, such as plasma current, density, shapes,..
II) In the ASDEX Upgrade device, at IPP institute,Garching, Germany,during Shattered Pellet Injector (SPI) experiments,
III) In the Join European Torus (JET) device, at CCFE,Culham, UK,during Shattered Pellet Injector (SPI) experiments.
Such studies have been performed recently, in 2021/2021, in the framework of JET1/Tokamak exploitation WorkPackage (EUROFusion).TheThesis work consists in analyzing statistically magnetic, kinetic signals,Dalpha and Infra-red camera signals. The candidate should chooseone option(I or II or III), only.

Competenze richieste:Data analysis (Matlab, Python, IDL)
Stato: non assegnata

Cycle of studies: Master(LaureaMagistrale)
Degree course: Energy engineering(Ingegneria dell’Energia)

RFX Supervisor: L. Zanotto
Academic supervisor: P. Bettini

Title of the thesis: Measurement and control of DC current component in the MITICA Acceleration Grid Power Supply inverter system
Type: Experimental / Modelling

Description of the thesis:
The thesis deals with the measurement of the dc current component in the inverters of the MITICA Acceleration Grid Power Supply. After a literature survey on the subject of dc current generation and control on three phase inverter systems supplying power transformers, the student shall analyze the precision of the present current transducers andassessthe use of new transducers or methods to estimate the dc current component supplied by the inverters in different load conditions and transients. The thesiscan be completed by experimental measurements on a dummy load aimed at testing the new transducers or methods and reviewing the operation of the existing dc current controller, with focus on possible strategies for improvement.

Date: 10/03/2022
Status: Available

Cycle of studies:BachelorLT/ Master LM
Degree course:Energy engineering,Materials engineering, Chemical Engineering,Chemistry
Title of the thesis:Water chemistry definition forpowerplants cooling circuits
Type:experimental/modelling
RFX Supervisor:Claudia Gasparrini
Academic supervisor:Prof. Piergiorgio Sonato

Description of thethesis:
In the raceto harnesselectricityfrom nuclear fusionthe challenges related to materials integrity during long term operation of fusion reactors have to be overcome. One of such challenges yet to be solved is the mitigation of corrosion issues in the extreme conditions found in fusion reactors. The control of water chemistryin fusion cooling circuitsis a field of research that is taking more interest lately. In this thesis you will get an overview ofcooling circuit requirements for nuclear fusion experimental reactors and you will contribute directly to the development of water chemistry definitionfor the Divertor Tokamak Test (DTT)facility. DTTis an experimental facility under construction at ENEA Frascati, Italy dedicated to the optimization of the divertor, a key component in nuclear fusion power plants. DTT will exploit the alternation of water and borated water in the Vacuum Vessel (VV).The definition of an optimized water chemistry in the VV cooling circuit is key to ensure maximum availability of the reactor and ensuring materials integrity. During this thesis you will learn the techniques used in water chemistry optimization and perform experiments insupport oftheDTT water cooling circuit chemistry definition.

Status: available

Cycle of studies:Master LM
Degree course:Energy engineering
Title of the thesis:High-frequency modelling of the Acceleration Grid Power Supply of SPIDER experiment
Type:Modelling
RFX Supervisor:A. Ferro
Academic supervisor:P. Bettini


Description of thethesis:
SPIDER is the test-bed of the negative ion beam source of the ITER Heating Neutral Beam Injectors (NBI). The Acceleration Grid Power Supply (AGPS)provides negative dc voltages up to-96 kV to the SPIDER acceleration grids, and dc currents up to 75 A. Frequent arc breakdowns occur between the acceleration grids, due to the short gap required by the beam optics. They represent short-circuits at the AGPS output, which cause voltage collapse and high frequency voltage and current oscillations, which stress the AGPS and the other items connected at the same potential. A thesis is proposed, aiming at studying the propagation of these voltage transients along the AGPS output cable, and the voltage fluctuations occurring on the AGPS. The work includes the development of a high-frequency model of the AGPS components, considering the stray inductances and capacitances, estimated analytically, from test reports or through measurements on the field. The results of the model will be compared with the available measurements to provide a first validation, and will give useful inputs to define possible improvements of the plant.

Date:22/11/2021
Status:Available

Tipo di tesi:Laurea Magistrale
Corso di Laurea:Fisica
Tipologia:Analisi Dati/Modellistica
Titolo della tesi:Investigation of intrinsic error fields in MAST-U device
Relatore RFX:Lidia Piron
Relatore Accademico:Lidia Piron

Argomento della tesi:
-Motivation: the presence of spurious magnetic fields, due to imperfections or misalignment of coils, coil current feeds, eddy currents associated with 3D wall structures and ferritic material located in the vicinity of the plasma, asknown as error fields, are responsible of locked MHD modes, and thus plasma disruptions. The characterization of the intrinsic error field sources and the development of active control strategies, which aim at their minimization, are of vital importance in fusion devices. Studies carried out in present fusion devices can allow extrapolations towards ITER operation.
-Strategy:
1.Investigate the intrinsic error fields in MAST-U device (United Kingdom Atomic Energy Agency, Culham) by using multiple set of plasma diagnostics: magnetics, interferometer (density), Thomson scattering (Temperature) and infrared cameras.
2.Compare intrinsic error field source with modelling predictions
3.Test experimentally error field control
-Methodology:
1.Data analyses of a wide database of discharges
2.Deduce the error field correction currents
3.Compare the results with modelling predictions
-Framework of the study: EUROfusion Work Package tokamak exploitaion RT01: ITER baseline scenarios towards detachment and low collisionality

Competenze richieste:
Ambienti Python, IDL,Matlab.
Conoscenza degli argomenti trattati nei seguenti corsi della Laurea Magistrale in Fisica:
-Physics of fluids and plasmas
-Physics of nuclear fusion and plasma applications

Data della proposta:15/09/2021

Tipo di tesi:Laurea Magistrale
Corso di Laurea:LM in ingegneria dell’energiaelettrica
Tipologia:Analisi/Verifica teorica (/Sperimentale)
Titolo della tesi:Selezione della tecnologia più adatta allo sviluppo di sensori permisurarela corrente del fascio dell’esperimento SPIDER /Selection of the most suitable technology for measuring the SPIDER experiment’s beam current
Relatore RFX:Nicolò Marconato,MatteoBrombin
Correlatore RFX:Tommaso Patton
Relatore Accademico:Nicolò Marconato
Capogruppo:MatteoBrombin

Argomento della tesi:
L’esperimento SPIDER (https://www.igi.cnr.it/ricerca/negative-ion-neutral-beam-injection/spider/i-componenti-di-spider/) è in shut-downfino a dicembre 2022 per le riparazioni e i miglioramenti necessari derivanti dall’esperienza fatta nei primi anni di funzionamento dal 2018 ad oggi. Tra questi upgrades è prevista l’installazione della diagnostica current monitor per la misura della corrente del beam relativa a ciascuno dei 16 gruppi diaperture (beamlet groups) delle griglie di accelerazione. È necessario pertantoprogettareun sensore di correntein grado di misurare la corrente del fascio in uscita dalla griglia di terra per ciascuno dei 16 bealmlet groups. I 16 segnali di corrente daranno la misura della totale corrente di fascio, permettendo inoltre una valutazione dell’uniformità dello stesso.
Principali requisiti del sensore di corrente sono i seguenti:
-Misura sia della componente DC, sia della componentead alta frequenza(centinaia di kHz);
-Operazione in alto vuoto(10-6mbar);
-Resistenza a carichi termici non trascurabili;
-Elevata risoluzione e precisione in un range di correnticompreso tra100 mAe3 A;
-Immunità a campi magnetici DC esterni;
-Immunità alla componente a radiofrequenza di 1MHz della corrente del fascio;
-Immunità a breakdown elettrici
-Compatibilità meccanica con gli spazi disponibili davanti a ciascun beamlet group.
Allo studente è richiesto il supporto nell’analizzare quale tecnologia sia la più adatta tra 3 opzioni (Hall, Fluxgate, Fluxgate DCCD) rispetto ai requisiti precedentemente descritti. Ciò significa pertanto che, in base al momento di inizio della tesi rispetto al programma dello shutwdown di SPIDER, lo studente dovrà realizzare alcune delle seguenti attività:
-studiare e analizzarele 3 tecnologie;
-realizzare analisi FEM magnetiche per la valutazione della dimensione dei core magnetici necessari nei diversi casi, valutandone quindi la fattibilità dal punto di vista degli ingombri;
-valutare la complessità del circuito elettronico di controllo ed acquisizione, in particolare valutando la possibilità che questo possa essere completamente posizionato ex-vessel;
-realizzazione di primi prototipi preliminari.
Competenze richieste:Elettrotecnica/elettronica;discreta conoscenza della lingua inglese; esperienza con software FEM (utile ma non assolutamente necessaria)
Data della proposta:08/10/2021
Stato:non assegnata

Tipo di tesi:Laureamagistrale
Corso di Laurea:Ingegneria
Tipologia:numerica
Titolo della tesi:Electromagnetic modelling and design of a multi gap solution for the passive stabilizing shell of Reversed Field Pinch experiments
Relatore RFX:DomenicoAbate(Matteo Bonotto, Roberto Cavazzana, Lionello Marrelli)
Relatore Accademico:Paolo Bettini

Argomento della tesi:

The present thesis focuses onthe electromagnetic modelling and design of a multi gap solution for the passive stabilizing shell of magnetic confinement fusion experiments in reversed field pinch (RFP) configurations. The modelling activity would allow studying the effects of multiple gaps in the passive stabilizing shell surrounding a RFP plasma by means of electromagnetic models with different level of complexity. The effect ofdifferent number and shape of gaps will beinvestigated in terms of plasma stability by developing dedicated numerical codes based on FEM/BEM approach. The multi gap selected solution will then be analysed in terms of engineering design and manufacturing processes.
Competenze richieste:Elettrotecnica,Elettrotecnica computazionale,conoscenza base di linguaggi di programmazionee ambienti di sviluppo(MATLAB)
Data della proposta:24/09/2021
Stato:non assegnata

Tipo di tesi:Laureamagistrale
Corso di Laurea:Ingegneria
Tipologia:numerica
Titolo della tesi:Electromagnetic circuit modelling of RFPconfigurationin the RFX-mod2 experiment
Relatore RFX:Domenico Abate, (Matteo Bonotto, Roberto Cavazzana)
Relatore Accademico:Paolo Bettini

Argomento della tesi:

The present thesis focuses on studyingthe evolution of the Reversed Field Pinch(RFP) configuration in connection withbothcoils andpower supply circuitsby using 0D electromagnetic modelling (i.e. circuitmodelling). The power of circuit modelling is in its smart
approach that leads to relatively simple models easy to be implemented in computer simulators such as LTSPICE or SIMULINK. The focus is to investigate the evolution of RFP plasmas from two complementary point of views: from the plasma side by modelling its MHD evolution, and from the machine side(i.e. electromagnetic systems)byconsideringplasma evolutioneffects on the coils and integrated safety system.The proposed thesis would require a preliminary review of some of the most important contributions on this topic, individuating lacks and inconsistencies in the present available models by applying them to experimental RFX-mod data.Then, a more rigorous derivation will be derived starting from fundamental electromagnetic laws; then thereference RFP equilibrium can be inserted in the evolution equations only at a later stage of the derivation. This approach leads to clean equations in explicit formulation, which can be used for immediate practical purposeslike the calculation of the dissipative loop voltage, or to be inserted directly in a circuit simulator. Several upgrades can be implemented to the model: from the plasma side, a 1D evolution of the plasma current density can be coupled to circuit equations; from the magnet system side, the magnet fault detection system (RGM, Rilevamento Guasti del sistema Magnetico) can be included and tested to different plasma evolutions. In general, the model would allowto predict the macroscopic behaviour of the RFP experimental discharges and/or to allow verifications on the proper functionality of the magnet fault detection system. All the activity would be helpful for the future operations of theRFX-mod2 experiment located in Padua at Consorzio RFX laboratories.
Competenze richieste:Elettrotecnica(analisidi circuiti lineari),conoscenzabase di linguaggi di programmazione e ambienti di sviluppo (SIMULINK/MATLAB, LTSPICE)
Data della proposta:24/09/2021
Stato:non assegnata

Tipo di tesi:Laurea Magistrale
Corso di Laurea:LMin ingegneria dell’energiaelettrica
Tipologia:Sviluppo/Sperimentale
Titolo della tesi: Sviluppo e caratterizzazione delle sonde di campo magnetico locale per l’esperimento DTT
Relatore RFX:Nicolò Marconato
Relatore Accademico:Nicolò Marconato


Argomento della tesi:
L’esperimento da fusione Divertor Test Tokamak (DTT) è in fase di progettazione e realizzazione a Frascati, Italia. Ha lo scopo di affiancare l’operazione del reattore sperimentale ITER nello studio di configurazione alternative del divertore per limitare l’elevatissima densità di potenza qui concentrata, in particolare nelle terminazioni anomale di plasma. DTT, come tutte le attuali macchine da fusione a confinamento magnetico, necessitano di uncomplesso sistema di sonde magnetiche per il controllo del plasma. Sonde di campo locale (pick-up coils) e di flusso vengono utilizzate per la ricostruzione dell’equilibrio e dunque per un controllo di base fondamentale per l’operazione della macchina. Inoltre un sistemaavanzatopermette anche un controllo più avanzato e lo studio fisico di numerose instabilità del plasma. Le sonde magnetiche per macchine da fusione come DTT hanno requisiti molto stringenti in termini di accuratezza e robustezza, dato il lorofunzionamento inultra altovuotoe la necessitàdiresisterea stress termici estremi tra temperatura criogenicaed altetemperature(~200°C).
Allo studente è richiesto il supporto nello sviluppo di questo sistema che comprende alcune tr ale seguenti attività (in base al momento di inizio della tesi):
-Definizione del design della sonda;
-Studio integrato sonda-linea di trasmissione per la definizione dei requisiti dell’elettronica di acquisizione;
-Scelta dei materiali;
-Sviluppo prototipi e sistema sperimentale per test elettromagnetici prima e dopo stress dovutia cicli termici attesi.

Competenze richieste (se necessarie):Elettrotecnica e analisi parametrica di circuiti lineari, conoscenza base di linguaggi di programmazione Matlab o Python
Data dellaproposta:15/09/2021
Stato:non assegnata

Tipo di tesi:Laurea Magistrale
Corso di Laurea:LM in ingegneria dell’energiaelettrica
Tipologia:Modellistica/Sperimentale
Titolo della tesi:Validazione sperimentale del modello numerico per lo sviluppo della linea di trasmissione del NBI del macchina sperimentale DTT /Experimental validation of the numerical model or the design of the NBI transmission line for the DTT experiment
Relatore RFX:Nicolò Marconato
Relatore Accademico:Nicolò Marconato


Argomento della tesi:
L’esperimento da fusione Divertor Test Tokamak (DTT) è in fase di progettazione e realizzazione a Frascati, Italia. Ha lo scopo di affiancare l’operazione del reattore sperimentale ITER nello studio di configurazione alternative del divertore per limitare l’elevatissima densità di potenza qui concentrata, in particolare nelle terminazioni anomale di plasma. DTT sarà dotato di un Neutral Beam Injector (NBI) per il riscaldamento del plasma di energia pari a 500keV e potenza di 10 MW. È prevista una linea di trasmissione isolata in gas per il collegamento a 500kV DC dell’iniettore alle alimentazioni. Nei prossimi mesi sarà realizzato al Dipartimento di Ingegneria Industriale (DII) un esperimento per la validazione di un codice recentemente sviluppato in Comsol per la progettazione della linea e del bushing SF6-Aria attraverso cui l’NBI è alimentato. In base al momento di inizio della tesi, allo studente è richiesto il supporto nello sviluppo del mockup sperimentale mediante analisi numeriche e/o nella successiva operazione dell’esperimento per il benchmark codice-dati sperimentali.
Competenze richieste:Esperienza con software FEM(utile ma non assolutamente necessaria)
Data della proposta:15/09/2021
Stato:non assegnata

Tipo di tesi:Laurea magistrale
Corso di Laurea:Ingegneria
Tipologia:modellistica
Titolo della tesi:Studies on the application of MMC technology to the Acceleration Grid Power Supply
of the Neutral Beam Injector of DTT
Relatore RFX:A. Ferro, E. Gaio
Relatore accademico:P. Bettini

Argomento della tesi:
The neutral beam injector (NBI) of DTT, the experimental fusion reactor under construction in Frascati (Italy), will accelerate Hydrogen isotopes up to 500 keV. The corresponding power supply for the acceleration grids will provide 500 kV, divided in 3 stages, with a maximum current of about 60 A. One of the main requirements is the capability to limit the energy transferred during the frequent arc breakdowns occurring among the grids, and to restart in few ms once the dielectric insulation is restored. Prosecuting a previous research activity, it is proposed a thesis aiming at evaluating the feasibility of adopting the Modular Multilevel Converter (MMC) technology for this specific application. Widely used in industrial HVDC systems, MMCs has never been applied to HV PS for NBIs, but in principle it could guarantee high efficiency, accurate control of the voltage, and the reduction of the energy transferred to the arcs. In addition, being the MMCs typically insulated in air, the only gas-insulated components would remain the Transmission Line which connect the power supply to the load, simplifying the management of the plant. Unfortunately, the space available for the MMC installation in the DTT site is quite limited, thus the feasibility study shall include the optimization of the submodule topology to reduce the number of components and overall size, and the study of a suitable layout of the conversion towers, taking into consideration also the interface with the transformers and the required clearances for insulation. Starting from the previous work, the study of suitable feedback controls shall be deepen, taking into consideration the requirements in normal and anomalous conditions; this, in combination with the selected topologies, has a direct impact on the peak voltages on the conversion towers, thus on the clearances to be kept and the overall dimensions of the plant. A preliminary fault analysis should be pursued too, to design suitable protections ad highlight possible major issues with this technology.

Data della proposta:ottobre 2020
Stato:non assegnata

Tipo di tesi:Laurea Magistrale
Corso di Laurea:Ingegneria
Tipologia:teorica
Titolo della tesi: Study and modelling of a turbine-generator for the EU DEMO fusion power plant
Relatore RFX: A. Ferro / F. Gasparini
Relatore Accademico: P. Bettini

Argomento della tesi:
The DEMO fusion power plant will be the first fusion reactor to produce net electrical power to be delivered to the European Power Transmission Grid (PTG). DEMO specifications request the power plant to be able to produce at least 300 MW of net electrical power. However, to create and sustain a fusion grade plasma, hundreds of MW of electrical power are needed, which are referred to as recirculating power. Thus, the electrical generator of the plant will produce a gross electrical power of about 800 MW and, so, the electrical generator of DEMO will be rated for about 1 GVA. Generator of such power level are already available on the market and exploit well established technologies. Nonetheless, the DEMO generator could be subjected by anomalous electromechanical stress, since the recirculating power will feature huge power peaks with high power derivatives. The thesis,will focus on the setup of a model, based on the state-space representation, of the generator itself. Then, a rather simplified model of the steam turbine dynamic should be developed and integrated with the generator one. Finally, the closed loop control system of the turbine-generator group should be implemented in the model and, thus, the behavior of the overall system analyzed.
Competenze richieste: Macchine elettriche, azionamenti elettrici

Stato:non assegnata

Tipo di tesi:Laurea Triennale/Magistrale
Corso di Laurea: (Fisica/Ingegneria)
Tipologia:(sperimentale)
Titolo della tesi:Reconstruction of Negative Ion Beam Heat Flux profile on STRIKE by Neural Networks.
Relatore RFX: Rita Delogu, Gianluigi Serianni
Relatore Accademico: Gianluigi Serianni

Argomento della tesi:

Si propone la ricostruzione del flusso di energia incidente sul calorimetro diagnostico STRIKE mediante l’analisi delle misure termografiche sul retro del calorimetro utilizzando codici di intelligenza artificiale, in particolare le reti neurali. Questo progetto è la prosecuzione e il perfezionamento di un metodo già implementato, per poterlo utilizzare durante le fasi di operazione in real time di SPIDER.
Competenze richieste: Programmazione di base
Data della proposta: 15/01/2020
Stato:non assegnata

Tipo di tesi:Laurea Magistrale
Corso di Laurea:Area dell’Ingegneria Industriale
Tipologia:Sperimentale e numerica
Titolo della tesi:Sviluppo di un materiale termicamente ortotropo per diagnostica termografica di fasci di particelle.
Relatore RFX:M. Dalla Palma, R. Pasqualotto
Relatore Accademico:P. Sonato

Argomento della tesi:

Si propone lo studio di un materiale termicamente ortotropo per trasferire il campo di temperatura da una sorgente termica ad un ambiente di osservazione e misura protetto da interferenze. Il materiale verrà utilizzato per realizzare i pannelli di un calorimetro che arresti delle particelle ad alta energia e che trasferisca il campo di temperatura alla superficie opposta che sarà osservata con metodo termografico. I pannelli saranno composti da una struttura a celle ceramica o grafitica nella quale saranno inserite e fissate delle fibre ad alta conducibilità termica. Questa struttura permetterà di ottenere un elevato rapporto tra la diffusività termica lungo lo spessore e quella perpendicolare, nonché un’elevata resistenza meccanica alle tensioni indotte dalle dilatazioni termiche differenziali. Sono previste un’indagine sullo stato dell’arte, la realizzazione di un modello funzionale in scala, la simulazione delle prestazioni del prototipo per verificare le condizioni limite e la misura delle diffusività termiche direzionali.

Data della proposta:13/11/2019
Stato:non assegnata

Tipo di tesi:Laurea Triennale/Magistrale
Corso di Laurea: Fisica/Ingegneria
Tipologia: sperimentale
Titolo della tesi:Evaluation of Negative Ion Beam Heat Flux profile on STRIKE by Neural Networks.
Relatore RFX: Rita Delogu, Gianluigi Serianni
Relatore Accademico: Paolo Bettini

Argomento della tesi:

Si propone la ricostruzione del flusso di energia incidente sul calorimetro STRIKE mediante l’analisi delle misure termografiche sul retro del calorimetro utilizzando codici di intelligenza artificiale, in particolare le reti neurali.
Competenze richieste: Programmazione di base

Stato:non assegnata

Tipo di tesi:Laurea Magistrale Ingegneria
Corso di Laurea:Area dell’Ingegneria Industriale (Meccanica, Chimica e dei Materiali/dei Processi Industriali, Energetica, Energetica)
Tipologia:teorica e numerica
Titolo della tesi: Thermo-hydraulic and integrated modelling in support of DEMO plant design.
Relatore RFX:Matteo Zaupa, Mauro Dalla Palma
Relatore Accademico:P. Sonato

Argomento della tesi:
Fusion power plants should provide a baseload supply of large amounts of electricity. The path towards this goal runs through the demonstration fusion power plant (DEMO) that will be operated as a steady state electricity source, although the near term conservative operation will be pulsed to cope with physics and technology limits. This pulsed scenario, with temperature range of the primary coolant depending on the breeding blanket concept, represents a predictable intermittent thermal energy source producing a cyclic load and so requiring thermal energy storage through heat transfer fluids and media. Energy storage could enhance the economic viability and profitability of the plant, but with lower temperatures at the secondary circuit and therefore decreasing the thermal efficiency of the power cycle.
The work will consist of sizing and designing the cooling plant to exhaust the thermal power and developing 3D-1D coupled thermo-hydraulic models of the first wall and breeding blanket to characterise and simulate the conditions of the heat sources. Then, the transfer of the heat load from the primary to the secondary circuit will be simulated in an integral plant model including concepts of energy storage systems and electromechanical generators.

Stato: non assegnata

Tipo di tesi:Laurea triennale o Laurea Magistrale
Corso di Laurea:Ingegneria
Tipologia:teorica+ calcolo
Titolo della tesi:progetto elettrostatico e analisi strutturale dello schermo elettrostatico intermedio dell'esperimento MITICA
Relatore RFX:G. Chitarin
Relatore Accademico:G. Chitarin

Argomento della tesi:

Le prove di caratterizzazione dell’isolamento dell’esperimento MITICA verranno eseguita a tensione crescente fino ad 1 MV, in vuoto e in gas a bassa pressione. Per ridurre la probabilità di scarica elettrica, durante tali prove si prevede di inserire nel Vessel di MITICA uno schemo elettrostatico a potenziale intermedio tra l’elettrodo in tensione e terra. Lo scopo della tesi è progettare tale elettrodo definendone forma, dimensioni e materiali mediante simulazioni elettrostatiche e strutturali. Verranno utilizzate analisi FEM strutturali e analisi FEM elettrostatiche.

Stato: non assegnata

Tipo di tesi:Laurea magistrale
Corso di Laurea:Ingegneria
Tipologia:modellistica
Titolo della tesi:Applicazione della tecnologia MMC agli alimentatori in alta tensione per iniettori di atomi neutri
Relatore RFX:A. Ferro, E. Gaio
Relatore accademico:P. Bettini

Argomento della tesi:
Gli iniettori di atomi neutri previsti nei reattori a fusione termonucleare a confinamento magnetico operano con tensioni di accelerazione dell'ordine di centinaia di kV. Il relativo sistema di alimentazione deve fornire queste tensioni, eventualmente suddivise in alcuni stadi intermedi, e correnti di alcune decine di Ampere, con la capacità di limitare l'energia trasferita durante i frequenti archi elettrici tra le griglie di accelerazione e ripartire in pochi ms una volta ripristinato l'isolamento. Nell'esperimento MITICA operato dal Consorzio RFX, la tensione di accelerazione massima prevista è di 1 MV (suddivisa in 5 stadi da 200 kV) e viene generata da trasformatori di step-up, alimentati da inverter, e seguiti da raddrizzatori a diodi isolati in SF6, connessi a un filtro RC in alta tensione anch'esso in SF6. Si propone un’attività di tesi volta a valutare la fattibilità e l’eventuale convenienza di adottare topologie alternative, in particolare i Modular Multilevel Converters (MMC), che si stanno dimostrando molto vantaggiose nell'ambito dei sistemi HVDC industriali, considerando sia la compatibilità con i requisiti peculiari dell'applicazione, sia l'impatto sugli ingombri rispetto alla soluzione sopra descritta.

Stato: non assegnata

Tipo di tesi: Magistrale
Corso di Laurea:  Ingegneria / Fisica

Tipologia: Sperimentale
Titolo della tesi: Resonant field amplification in JET high pressure scenarios

Relatore RFX: Lidia Piron

Relatore Accademico: Lidia Piron

Argomento della tesi:

In magnetic fusion devices to probe plasma stability, magnetic field perturbations induced by means of external coils are applied in high pressure regimes in the so-called  resonant field amplification technique. Such a technique has been extensively applied in high-beta plasmas performed in the JET tokamak (Culham, Oxfordshire, UK). In this project, data from multiple diagnostics, such as magnetics, Thomson scattering, and equilibrium reconstructions will be analyzed to characterize the plasma amplification process.

Competenze richieste: Data analysis (Matlab, Python, IDL)
Stato: non assegnata

Tipo di tesi: Magistrale
Corso di Laurea:  Ingegneria / Fisica

Tipologia: Sperimentale
Titolo della tesi: Characterization of magnetic field errors in MAST-U coil manufacturing

Relatore RFX: Lidia Piron

Relatore Accademico: Lidia Piron
Argomento della tesi:

Error fields are spurious magnetic field perturbations that  can degrade the plasma performance in a magnetic fusion devices through various mechanisms, such as rotation braking, fast particles losses and MHD instability onset. The identification of error field sources thus plays a vital role to guarantee  safe and robust plasma operations. In this project, the validation of a 3D electro-magnetic modelling of poloidal field coils again experimental data will be carried to detect error field sources in the coil manufacturing process in the MAST-U device (Culham, Oxfordshire, UK).

Competenze richieste: Data analysis (Matlab, Python, IDL)
Stato: non assegnata

Cycle of studies: 2nd (master)
Degree course: Engineering/Physics/Material Sciences
Title of the thesis: Simulation of plasma parameters towards the optimization of first wall components by Glow-Discharge Cleaning
Type: theoretical/modelling
RFX Supervisor: Stefano Ciufo & Ruggero Milazzo
Academic supervisor: Matteo Zuin (Physics) or Emanuele Sartori (Engineering) or Sonato (Material Sciences)

Group Leader (Lorella Carraro)

Description of the thesis: The Glow-Discharge Cleaning (GDC) is one of the most important systems for plasma consistency in fusion reactors, during experimental campaigns. It is usually employed by considering only the current required for sputtering on the first wall materials and with relatively high voltages. The purpose of this thesis is to adapt a Particle-In-Cell (PIC) code in order to simulate plasma-wall interactions from the perspective of the RFX facing Carbon tiles. In particular, energy distribution and impact angles are quantities that must be estimated, depending on boundary conditions, so to serve as input for modeling solid-state phenomena (sputtering, impurity retention/desorption, defect generation, etc.) that determine fusion performance in turn. The importance of this study lies in gaining understating of the physics ruling plasma-wall interactions and the correct application of boundary condition. In this way, GDC operations can be significantly optimized by reduction in the resources required for the operation and in the time required for execution. The candidate's thesis will focus on adapting the PIC code to create a map enclosing energy and angles for different species contained in the plasma and with respect to the facing wall. Results will be analysed to describe plasmas and they will deal with graphic visualization of the abovementioned parameter space with final aim of better understanding the dynamics of plasma-wall interaction. The work will take place at Consorzio RFX.
 
Date: November 24nd, 2022

Tipo di tesi: (Triennale/Magistrale) magistrale/ triennale con tirocinio
Corso di Laurea: ingegneria

Tipologia: (sperimentale/teorica/modellistica) modellistica
Titolo della tesi: Study of the interactions between the Stray Field Shielding System (SFSS) and the Gas injection and Vacuum System (GVS) in DTT Neutral Beam Injector (NBI)

Proponente/Relatore RFX: Agostinetti

Relatore Accademico: Sonato
Capogruppo: Rizzolo

Responsabile di Programma: Murari

Argomento della tesi (in inglese):

The main purpose of the Divertor Tokamak Test facility (DTT) is to study solutions to mitigate the issue of power exhaust in reactor relevant conditions, particularly exploring alternative power exhaust solutions for the machines that will follow ITER, in particular the demonstrative power plant DEMO that is currently in the conceptual design phase.

In this context, the principal objective of DTT is to mitigate the risk of a difficult extrapolation to a fusion reactor of the conventional divertor based on detached conditions, which will be tested in ITER. The task implies the study of the completely integrated power exhaust problems and the demonstration of how the possible implemented solutions (e.g., advanced divertor configurations or liquid metals) could be integrated in the DEMO device and other fusion reactors.

The key feature is to equip the machine with a significant amount of auxiliary heating power in order to test innovative divertor concepts. DTT will be able to explore various magnetic divertor configurations and in order to reach a reactor relevant power flow to the divertor, 45 MW of auxiliary power will have to be coupled to the plasma using the following systems: Electron Cyclotron Resonant Heating (ECRH), Ion Cyclotron Resonant Heating (ICRH) and Neutral Beam Heating (NBH).

In this framework, the conceptual design of the beamline for the DTT Neutral Beam Heating system, based on negative ions, is overviewed, with a particular focus on the technical solutions adopted to fulfill the requirements and maximize beamline performances.

The NBI system features a beamline providing deuterium neutrals (D0) with an energy of 510 keV and an injected power of 10 MW.

Two key aspects in the DTT NBI design are the Stray Field Shielding System (SFSS) and the Gas injection and Vacuum System (GVS). The first system has the function of shielding the NBI from the stray magnetic field produced by the tokamak coils, as this field would have a detrimental effect on the NBI efficiency. The second system is designed to keep the pressure inside the vacuum vessel as low as possible in order to decrease the beam losses and keep the NBI efficiency high.

The goal of this thesis is to find a suitable design configuration in order to have both the systems working properly. The candidate will be trained on the usage of the necessary simulations codes by the design team and followed during the development of the possible design solutions.

Competenze richieste (se necessarie):
Data della proposta: 12/12/2022

Tipo di tesi: Laurea Magistrale

Corso di Laurea: Ingegneria
Tipologia: progettazione enumerica

Titolo della tesi:

Thermo-hydraulic design and specification for the construction of the DTT in-vessel coils

Progetto termo-idraulico e specifica per la costruzione delle bobine in-vessel di DTT

Proponente: dr. ing. Mauro Dalla Palma

Capogruppo RFX: dr. ing. Andrea Rizzolo

Relatore Accademico: prof. ing. Piergiorgio Sonato

Argomento della tesi:

DTT is one of the largest superconducting tokamak under construction with the mission to get scientific and technological proofs of power exhaust in prospect of the first nuclear fusion power plant [1, 2]. The 5.5MA maximum plasma current, 6T toroidal magnetic field at the plasma center, and 2.19m plasma radius make DTT a flexible and compact facility for testing D-shaped plasmas with different configurations of heat load spreading.

The mechanical systems of DTT are designed and integrated analysing interfaces consistently with machine operating states including plasma operation, disruptions, baking, seismic event, testing, and maintenance.

The DTT in-vessel coil system comprises:

• vertical stability coils: 2 poloidal field coils located above and below the tokamak's mid-plane designed for fast vertical stabilization of the plasma;
• divertor coils: 4 coils located in the divertor region designed for sweeping control on divertor legs and local modification of the plasma configuration;
• edge localized mode (ELM) coils: 27 coils fixed to the inner-shell of the vacuum vessel designed for active control of edge-localized modes and error fields.

The design if the in-vessel coils has been defined and in particular the same coil conductor will be used for manufacturing all the coils and it will consist of a stainless steel jacket, an inner copper conductor and a techno-polymer insulation.

Steady state and transient thermo-hydraulic analyses of the coil conductor based on analytical and finite element methods in the solid domain are needed applying the electrical current as a time function during the machine operating states. Thermo-mechanical verifications of the coil conductor are needed in the region of the connection with coil feeders and along coil turns/branches applying available electromagnetic loads. The analyses will contribute to the validation of the already carried out preliminary design in order to proceed with the preparation of the technical specification for the procurement of the conductor and of the coils.

A collaboration with IPP Team working on ASDEX-U is ongoing.

References

[1] R. Ambrosino, “DTT - divertor tokamak test facility: A testbed for DEMO,” Fusion Engineering and Design, vol. 167, p. 112330, 2021

[2] R. Martone, R. Albanese, F. Crisanti, A. Pizzuto, P. Martin Eds.. “DTT Divertor Tokamak Test facility Interim Design Report, ENEA (ISBN 978-88-8286-378-4), April 2019 ("Green Book")”

Data proposta: 02/12/2022

Tipo di tesi: Laurea Magistrale

Corso di Laurea: Ingegneria
Tipologia: progettazione enumerica

Titolo della tesi:

Analyses for the integration of seismic isolation dampers in the DTT facility

Analisi per l’integrazione di isolatori e dissipatori sismici nella macchina DTT

Proponente: dr. ing. Mauro Dalla Palma

Capogruppo RFX: dr. ing. Andrea Rizzolo

Relatore Accademico: prof. ing. Piergiorgio Sonato

Argomento della tesi:

DTT is one of the largest superconducting tokamak under construction with the mission to get scientific and technological proofs of power exhaust in prospect of the first nuclear fusion power plant [1, 2]. The 5.5MA maximum plasma current, 6T toroidal magnetic field at the plasma center, and 2.19m plasma radius make DTT a flexible and compact facility for testing D-shaped plasmas with different configurations of heat load spreading.

The mechanical systems of DTT are designed and integrated analysing interfaces consistently with machine operating states including plasma operation, disruptions, baking, seismic event, testing, and maintenance.

The DTT in-vessel coil system comprises:

• vertical stability coils: 2 poloidal field coils located above and below the tokamak's mid-plane designed for fast vertical stabilization of the plasma;
• divertor coils: 4 coils located in the divertor region designed for sweeping control on divertor legs and local modification of the plasma configuration;
• edge localized mode (ELM) coils: 27 coils fixed to the inner-shell of the vacuum vessel designed for active control of edge-localized modes and error fields.

The DTT facility will be supported by a basement designed between the torus complex and the ground foundation in the tokamak hall. The integration of isolation dampers in the basement is under evaluation as a seismic protection in order to dynamically separate the torus complex from the foundation, then the amount of energy that is transferred to the tokamak during an earthquake is reduced significantly. 

The study of the isolation system includes the identification of the type of bearing like elastomeric pads, sliding plates or inverted pendulums to support the weight of the structure and to provide some level of energy dissipation, typically in the form of hysteretic damping.

Equivalent static and seismic spectra analyses can be performed using the finite element method and with acceleration spectra reduced with respect to the normalised response of ground motion. Moreover, a CAD model can be developed to verify the system integration and interfaces.

The activity will be carried out in collaboration with the DTT Building Team.

References

[1] R. Ambrosino, “DTT - divertor tokamak test facility: A testbed for DEMO,” Fusion Engineering and Design, vol. 167, p. 112330, 2021

[2] R. Martone, R. Albanese, F. Crisanti, A. Pizzuto, P. Martin Eds.. “DTT Divertor Tokamak Test facility Interim Design Report, ENEA (ISBN 978-88-8286-378-4), April 2019 ("Green Book")”

Data proposta: 02/12/2022