[Elenco soci]


Marzullo Domenico

Professore Associato


Università degli Studi di Trieste
dmarzullo@units.it

Sito istituzionale
SCOPUS ID: 56568205000
Orcid: 0000-0001-9764-1725



Pubblicazioni scientifiche

[1] You J.H., Mazzone G., Visca E., Greuner H., Fursdon M., Addab Y., Bachmann C., Barrett T., Bonavolontà U., Böswirth B., Castrovinci F.M., Carelli C., Coccorese D., Coppola R., Crescenzi F., Di Gironimo G., Di Maio P.A., Di Mambro G., Domptail F., Dongiovanni D., Dose G., Flammini D., Forest L., Frosi P., Gallay F., Ghidersa B.E., Harrington C., Hunger K., Imbriani V., Li M., Lukenskas A., Maffucci A., Mantel N., Marzullo D., Minniti T., Müller A.V., Noce S., Porfiri M.T., Quartararo A., Richou M., Roccella S., Terentyev D., Tincani A., Vallone E., Ventre S., Villari R., Villone F., Vorpahl C., Zhang K., Divertor of the European DEMO: Engineering and technologies for power exhaust, Fusion Engineering and Design, 175, (2022). Abstract
X

In a power plant scale fusion reactor, a huge amount of thermal power produced by the fusion reaction and external heating must be exhausted through the narrow area of the divertor targets. The targets must withstand the intense bombardment of the diverted particles where high heat fluxes are generated and erosion takes place on the surface. A considerable amount of volumetric nuclear heating power must also be exhausted. To cope with such an unprecedented power exhaust challenge, a highly efficient cooling capacity is required. Furthermore, the divertor must fulfill other critical functions such as nuclear shielding and channeling (and compression) of exhaust gas for pumping. Assuring the structural integrity of the neutron-irradiated (thus embrittled) components is a crucial prerequisite for a reliable operation over the lifetime. Safety, maintainability, availability, waste and costs are another points of consideration. In late 2020, the Pre-Conceptual Design activities to develop the divertor of the European demonstration fusion reactor were officially concluded. On this occasion, the baseline design and the key technology options were identified and verified by the project team (EUROfusion Work Package Divertor) based on seven years of R&D efforts and endorsed by Gate Review Panel. In this paper, an overview of the load specifications, brief descriptions of the design and the highlights of the technology R&D work are presented together with the further work still needed.

Keywords: DEMO | Divertor | Fusion reactor | High-heat-flux | Plasma-facing component | Power exhaust

[2] Moro F., Marocco D., Belli F., Brolatti G., Colangeli A., Crescenzi F., Flammini D., Fonnesu N., Gandolfo G., Kantor R., Mariano G., Marzullo D., Podda S., Sancristobal D., Villari R., Esposito B., Nuclear Analyses for the Assessment of the Loads on the ITER Radial Neutron Camera In-Port System and Evaluation of Its Measurement Performances, IEEE Transactions on Plasma Science, (2022). Abstract
X

The radial neutron camera (RNC) is a key ITER diagnostic system designed to measure the uncollided 14-and 2.5-MeV neutrons from deuterium&#x2013;tritium (DT) and deuterium&#x2013;deuterium (DD) fusion reactions, through an array of detectors covering a full poloidal plasma section along collimated lines of sight (LoS). Its main objective is the assessment of the neutron emissivity/<inline-formula> <tex-math notation="LaTeX">$\alpha $</tex-math> </inline-formula> source profile and the total neutron source strength, providing spatially resolved measurements of several parameters needed for fusion power estimation, plasma control, and plasma physics studies. The present RNC layout is composed of two fan-shaped collimating structures viewing the plasma radially through vertical slots in the diagnostic shielding module (DSM) of ITER Equatorial Port 1 (EP01): the ex-port subsystem and the in-port one. The ex-port subsystem, devoted to the plasma core coverage, extends from the Port Interspace to the Bioshield Plug: it consists of a massive shielding unit hosting two sets of collimators lying on different toroidal planes, leading to a total of 16 interleaved LoS. The in-port system consists of a cassette, integrated inside the port plug DSM, containing two detectors per each of the six LoS looking at the plasma edges. The in-port system must guarantee the required measurement performances in critical operating conditions in terms of high radiation levels, given its proximity to the plasma neutron source. This article presents an updated neutronic analysis based on the latest design of the in-port system and port plug. It has been performed by means of the Monte Carlo MCNP code and provides nuclear loads on the in-port RNC during normal operating conditions (NOC) and inputs for the measurement performance analysis.

Keywords: Collimators | Detectors | Heating systems | ITER | MCNP | Monte Carlo methods | neutron diagnostics | neutron measurements | Neutrons | Plasmas | Plugs | radial neutron camera (RNC) | radiation transport | Solid modeling

[3] Renno F., Papa S., Marzullo D., Barbato F.C.T., Barbarino G., Virtual Prototyping and FEM Analysis of the Crystal Eye Detector, Lecture Notes in Mechanical Engineering, 668-674, (2022). Abstract
X

The main aim of this article is to describe the design of a new sensor to study the electromagnetic field portions of gravitational waves. On August 17, 2017, the observation of the gravitational wave event started the era of multi-messenger astronomy. Therefore, new tools and optimal synchronization of the available telescopes are needed. The sensor that is designed is a cross-cutting technology, it is named Crystal Eye: a wide field of view in the energy field from 10 keV to 10 meV with a structure made of pixels. As the detector will be involved in the mission in 2023, the virtual prototype phase needed for optimization and production of the payload has been completed. Particular attention was paid to the results of the FEM analysis carried out to examine and predict the thermal and vibration behavior of the conceived mock-up during the launch phase and under strong temperature variations in the space environment.

Keywords: Detector | FEM | Vibration and thermal analysis | Virtual prototyping

[4] Salvato R., Marra G., Scardamaglia P., Di Gironimo G., Marzullo D., Mozzillo R., Design and Integration of Automation Systems with Manual Operation: Small and Medium Enterprises Issues, Lecture Notes in Mechanical Engineering, 298-307, (2022). Abstract
X

Today it is more and more mandatory for all commercial companies to comply with the principles and methodologies of Industry 4.0 and to achieve the related capabilities protecting their competitiveness and taking a leading-edge position on market as regards technologies. Specifically, the whole production and sale system must achieve the fundamental characteristics of Industry 4.0 approach, but specially the manufacturing companies must also change and update their management procedures, internal organization, resource training, assets and all production process to keep safe their current business capacities. This evolution process is even more critical for Small and Medium Enterprises (SME), that traditionally tend to be conservative and to protect their way of operation, usually characterized by a low level of automation. The work presented focuses on the design and integration of a semi-automatic welding cell of train bolster in a SME which is currently realizing a project aimed to the acquisition of Industry 4.0 capabilities, with special focus on manufacturing processes. Among them, one of the most important is the production of welded-steel critical structures, that the Company supplies to prime manufacturer of railway rolling stock systems. The experience gained during the activity, the criticalities due to the integration processes and the adopted design methodologies are here described. The work has been carried out consistently with the Systems Engineering principles, starting from the requirements elicitation and analysis to the systematic approach for the design and integration activities.

Keywords: CAD | Design methodologies | Industry 4.0 | Internet of things (IoT) | Systems engineering | Welding process

[5] Marzullo D., Di Gironimo G., Lanzotti A., Mozzillo R., Tarallo A., Requirements Engineering in Complex Systems Design, Lecture Notes in Mechanical Engineering, 658-667, (2022). Abstract
X

The realization of nuclear fusion reaction as energy source is under investigation, among the scientific community, through the design and development of tokamak reactors. Among the several experiments worldwide, the ITER project is the major international experiment and it involves several research institutes from several countries. In such a project, a Systems Engineering (SE) approach is requested to organize and manage the design due to its highly integrated design, the safety requirements related to nuclear aspects and the complex procurement scheme. The SE discipline focuses the attention on the requirements which are crucial for every successful project, defining what the stakeholders want from a potential new system, namely what the system must do to satisfy stakeholders need. Correctly stating WHAT is needed for the system, it is possible to obtain its conceptual design (HOW) as much as possible complying the requirements. The incorrect definition of requirements often leads to the failing of a project. Stakeholders’ needs are written in Natural Language that is generally ambiguous, imprecise, incomplete and redundant. Their transformation into SMART requirements is crucial to avoid design failure. However, it requires a great expertise, unless a specific procedure is assessed. To this end, this work presents a specific procedure based on “like-mind” processes to make systematic the SMART requirements definition and assessment from stakeholders needs. The procedure is based on a demand/response framework and it is developed to obtain ITER requirements. However, it can be easily extended to every project using its own specifications. A specific case study on ITER Remote Handling is presented in this paper as example of the conceived requirements transformation procedure.

Keywords: ITER tokamak | Requirements engineering | SMART requirements | Systems engineering

[6] Centioli C., Crescenzi F., Marzullo D., Kantor R., Brolatti G., Kotula J., de Bilbao Alcantara L., Etxeita Arriaga B., Eletxigerra Aja I., Marocco D., Esposito B., Krasilnikov V., Giacomin T., Interface Definition and Integration in the Equatorial Port 01 of the ITER In-Port Radial Neutron Camera, Fusion Engineering and Design, 172, (2021). Abstract
X

The ITER Radial Neutron Camera is a diagnostic whose objective is measuring neutron emissivity and fusion power density through an array of detectors placed in collimating structures. The RNC is composed of two subsystems (In-Port RNC and Ex-Port RNC), located in the Equatorial Port 01 of the ITER tokamak. Although the measurements from the RNC are required for ITER D-T phase, its In-Port components must be ready for Assembly phase 2. Consequently, the two subsystems will be delivered at different times. At the current status of the design the In-Port RNC interfaces must be defined, if not fully specified, in order to allow for the subsystem integration in the Port Plug. A thorough assessment of the interfaces of the subsystem with all the diagnostics, plants and services in the port has been made, taking into account the concurrent development of the Equatorial Port 01 and the progress in the design of some of the subsystem components that may affect the identification of interfacing Plant Systems. This paper deals with the process that led to definition of the internal and external interfaces of the In-Port RNC, highlighting the main issues and the solutions adopted to perform integration within the Equatorial Port Plug 01.

Keywords: Integration | Interfaces | Iter diagnostics | Radial neutron camera

[7] Militello F., Aho-Mantila L., Ambrosino R., Body T., Bufferand H., Calabro G., Ciraolo G., Coster D., Di Gironimo G., Fanelli P., Fedorczak N., Herrmann A., Innocente P., Kembleton R., Lilburne J., Lunt T., Marzullo D., Merriman S., Moulton D., Nielsen A.H., Omotani J., Ramogida G., Reimerdes H., Reinhart M., Ricci P., Riva F., Stegmeir A., Subba F., Suttrop W., Tamain P., Teschke M., Thrysoe A., Treutterer W., Varoutis S., Wensing M., Wilde A., Wischmeier M., Xiang L.Y., Preliminary analysis of alternative divertors for DEMO, Nuclear Materials and Energy, 26, (2021). Abstract
X

A physics and engineering analysis of alternative divertor configurations is carried out by examining benefits and problems by comparing the baseline single null solution with a Snowflake, an X- and a Super-X divertor. It is observed that alternative configurations can provide margin and resilience against large power fluctuations, but their engineering has intrinsic difficulties, especially in the balance between structural solidity and accessibility of the components and when the specific poloidal field coil positioning poses further constraints. A hybrid between the X- and Super-X divertor is proposed as a possible solution to the integration challenge.

Keywords: Alternative divertor configurations | DEMO | Divertor design

[8] Renno F., Barbato F., Barbarino G., Marzullo D., Guida R., Papa S., Systems Engineering approach for the concept design of the Crystal Eye detector, International Journal on Interactive Design and Manufacturing, 15(1), 81-84, (2021). Abstract
X

Main targets of this activity research are the making and the optimization of new detectors by means of the Systems Engineering methods. With the observation of the gravitational wave event of August 17th, 2017 and then with those of the extragalactic neutrino of September 22nd, the Multimessenger Astrophysics era began. It is a new way of exploring the Universe, powered by globally coordinated observations of several experiments. So, new X and gamma rays’ detectors solutions are needed in order to provide competitive results in the energy range 10 keV–10 meV. Here is briefly described how the Systems Engineering can improve the development of the proposal of a new technique: The Crystal Eye, a wide field of view detector with a good spatial resolution obtained thanks to a high pixelation.

Keywords: Astrophysics | Crystal Eye | Detectors | Optimization | Systems Engineering

[9] Mozzillo R., Bachmann C., Aiello G., Marzullo D., Design of the European DEMO vacuum vessel inboard wall, Fusion Engineering and Design, 160, (2020). Abstract
X

The pre-concept design of the DEMO Vacuum Vessel is going on in view of the 2020 gate review; moreover the nuclear heat loads on the vessel inner shell were determined and found to be about one order of magnitude higher compared to ITER. A subsequent thermal-structural analysis of the vessel inner shell revealed high thermal stresses and a large temperature gradient through the inner shell thickness. Given the simultaneous occurrence of primary membrane stresses in the entire vessel inboard wall and, in proximity of the vessel ribs, high bending stresses due to the coolant pressure, a survey of all options within the design rules was required to identify the inter-dependencies of the individual stress limits (primary membrane, primary bending, thermal membrane plus bending). In order to face this kind of issues a detailed assessment on the design of the inboard wall of DEMO Vacuum Vessel has been conducted and is presented here. The current work evaluates both P and S type damages for the inboard wall of DEMO Vacuum Vessel in case of high nuclear heat load, vacuum vessel coolant pressure and toroidal field coil fast discharge. The elastic analysis method has been used to check the rules for prevention of both types of damage. The rules applied to prevent the aforementioned damages are compliant to Level A criteria, in case of negligible creep and negligible irradiation. In order to check the structural integrity of the inboard wall of DEMO VV against high thermal and mechanical loads, optimization structural analyses were performed and checked against the rules provided in the applicable design code (RCC MRx).

Keywords: Breeding blanket | CAD | DEMO | FEM | Ratcheting | Vacuum vessel

[10] Bonavolontà U., Bachmann C., Coccorese D., Di Gironimo G., Imbriani V., Marzullo D., Mazzone G., Vorpahl C., You J.H., EU-DEMO divertor: Cassette design and PFCs integration at pre-conceptual stage, Fusion Engineering and Design, 159, (2020). Abstract
X

The pre-conceptual design of the DEMO divertor cassette with a novelty, alternative path of the main cooling pipes inside cassette body is presented in this paper, focusing on cassette design and Plasma Facing Components (PFC) integration. The divertor cassette design is reviewed, considering recent updates in the DEMO configuration model as presented by the Programme Management Unit (PMU) in 2018. The new configuration requires the cooling pipes to be integrated inside the cassette body. The components affected by these changes and the impact on the divertor design are analyzed. The study focuses on a new integration system between cassette and cooling pipes. The paper describes the integration on the new cassette geometry and the divertor sub-systems. The design activities related to this system are discussed in detail in terms of CAD modeling and considerations with respect to manufacturing such as welding technologies and non-destructive testing.

Keywords: Cooling pipes | DEMO | Divertor cassette | Divertor target

[11] Marzullo D., Ambrosino R., Castaldo A., Di Gironimo G., Merriman S., Preliminary engineering assessment of alternative magnetic divertor configurations for EU-DEMO, Fusion Engineering and Design, 158, (2020). Abstract
X

One of the main challenges in the roadmap to the realization of fusion energy is to develop a heat and power exhaust system able to withstand the large loads expected in the divertor of a fusion power plant. The challenge of reducing the heat load on the divertor targets is addressed, within the mission 2 ‘Heat-exhaust systems’, through the investigation of divertor configurations alternative to the standard Single Null (SN), such as the Snowflake (SF), Double Null (DN), X and Super-X (SX) divertors. This paper focuses on a preliminary engineering assessment of the alternative configurations proposed for the EU DEMO reactor. Starting from the description of the optimized plasma shape developed for each configuration, the 3D geometrical description of the Magnet System and of the main Mechanical Structures (Vacuum Vessel and in-vessel components) is presented. Based on the 3D geometry, the compatibility of the location and dimensions of ports with Remote Maintenance needs is discussed and possible design optimizations are proposed both for the Magnets system and the mechanical structures design. Finally, the various configurations are compared with regard to the engineering and feasibility aspects.

Keywords: Alternative magnetic configurations | CAD | Conceptual design | DEMO | Divertor concept

[12] Imbriani V., Bonavolontà U., Di Gironimo G., El Shawish S., Fursdon M., Giannone L., Marzullo D., Mazzone G., Visca E., You J.H., Insulated fixation system of plasma facing components to the divertor cassette in Eurofusion-DEMO, Fusion Engineering and Design, 158, (2020). Abstract
X

The design activities of an insulated Plasma Facing Components-Cassette Body (PFCs-CB) support has been carried out under the pre-conceptual design phase for Eurofusion-DEMO Work Package DIV-1 “Divertor Cassette Design and Integration” - Eurofusion Power Plant Physics & Technology (PPPT) program. The Eurofusion-DEMO divertor is a key in-vessel component with PFCs which directly interact with the plasma scrape-off layer. The PFCs have to cope with high heat loads, neutron irradiation and electromagnetic loads. The mechanical integrity of the PFCs and water cooling pipes can be jeopardized by high heat loads and by electromagnetic loads generated in a disruption event. In European-DEMO the possibility to estimate the heat load by measuring the relative thermocurrents is under investigation. In order to allow thermocurrents measurements, a divertor design option provides that PFCs are electrically insulated from CB. In this work authors aim to analyze the opportunity that the PFC-CB fixing system incorporates an electrical insulation system, thus acquiring also an important diagnostic role in the measurement of the thermocurrents and in the management of the current flows. The possible use of ceramic material (e.g. alumina) as the insulating layer between the support components is investigated.

Keywords: Divertor assembly | Divertor Plasma Facing Componentsfixation system | Eurofusion-DEMO

[13] Mazzone G., You J.H., Bachmann C., Bonavolontà U., Cerri V., Coccorese D., Dongiovanni D., Flammini D., Frosi P., Forest L., Di Gironimo G., Di Mambro G., Imbriani V., Maffucci A., Marzullo D., Di Maio P.A., Porfiri M.T., Vallone E., Villari R., Visca E., Vorpahl C., Eurofusion-DEMO Divertor - Cassette Design and Integration, Fusion Engineering and Design, 157, (2020). Abstract
X

The Eurofusion-DEMO design will complete the Pre Conceptual Design phase (PCD) with a PCD Gate, named G1, scheduled to take place in Q4 2020 that will focus on assessing the feasibility of the plant and its main components prior to entering into the Conceptual Design phase. In the paper first an overview is given of the Eurofusion-DEMO Divertor Assembly including design and interface description, systems and functional requirements, load specification, system classification, manufacturing procedures and cost estimate. Then critical issues are discussed and potential design solutions are proposed, e.g.: - Neutron material damage limits of the different (structural) materials present in the divertor assembly (as CuCrZr, Eurofer) and in the vacuum vessel (AISI 316 L(N)-IG); - Temperature hot spots in parts of the divertor assembly exposed to high nuclear heating and high heat radiation (from the plasma core or the separatrix) causing difficulties for active or passive cooling (e.g. cassette body structure, liner support structures, mechanical supports, divertor toroidal rails); - Arrangement and design of plasma-facing components and liner with pumping slot in the divertor cassette to enable pumping of exhaust gases from the lower port.

[14] Čufar A., Bachmann C., Eade T., Flammini D., Gliss C., Kodeli I.A., Marzullo D., Mazzone G., Vorpahl C., Wilde A., Shielding concept and neutronic assessment of the DEMO lower remote handling and pumping ports, Fusion Engineering and Design, 157, (2020). Abstract
X

Within the EUROfusion Power Plant Physics and Technology Department the DEMOnstrational fusion power plant (DEMO) is being developed. One of the fundamental challenges is the integration of ports in the vacuum vessel. The lower port of the DEMO machine is particularly challenging due to tight space constraints imposed by the toroidal field (TF) coils and the requirement to provide a large open duct through both the divertor and inside the port to enable for vacuum pumping. In addition, feeding pipes of divertor and tritium breeding blanket need to be integrated and access space must be provided for various remote handling operations. Several neutronics requirements need to be fulfilled, e.g. the nuclear heating of the superconducting TF coils and the gamma radiation levels inside the cryostat need to be limited to reduce occupational exposure to personnel during maintenance, and the irradiation damage and neutron heating in different components need to be considered in the design and limited. The results of neutronic analyses show that further shielding optimization is needed as maximum TF coil heating is still 5× the design limit and the SDDR values orders of magnitude above the target values inside the lower port duct. With this in mind the direction of future design developments is discussed.

Keywords: DEMO | Lower port | Material damage | Nuclear heating | Port integration

[15] Reimerdes H., Ambrosino R., Innocente P., Castaldo A., Chmielewski P., Di Gironimo G., Merriman S., Pericoli-Ridolfini V., Aho-Mantilla L., Albanese R., Bufferand H., Calabro G., Ciraolo G., Coster D., Fedorczak N., Ha S., Kembleton R., Lackner K., Loschiavo V.P., Lunt T., Marzullo D., Maurizio R., Militello F., Ramogida G., Subba F., Varoutis S., Zagórski R., Zohm H., Assessment of alternative divertor configurations as an exhaust solution for DEMO, Nuclear Fusion, 60(6), (2020). Abstract
X

Plasma exhaust has been identified as a major challenge towards the realisation of magnetic confinement fusion. To mitigate the risk that the single null divertor (SND) with a high radiation fraction in the scrape-of-layer (SOL) adopted for ITER will not extrapolate to a DEMO reactor, the EUROfusion consortium is assessing potential benefits and engineering challenges of alternative divertor configurations. Alternative configurations that could be readily adopted in a DEMO design include the X divertor (XD), the Super-X divertor (SXD), the Snowflake divertor (SFD) and the double null divertor (DND). The flux flaring towards the divertor target of the XD is limited by the minimum grazing angle at the target set by gaps and misalignments. The characteristic increase of the target radius in the SXD is a trade-off with the increased TF coil volume, but, ultimately, also limited by forces onto coils. Engineering constraints also limit XD and SXD characteristics to the outer divertor leg with a solution for the inner leg requiring up-down symmetric configurations. Capital cost increases with respect to a SND configuration are largest for SXD and SFD, which require both significantly more poloidal field coil conductors and in the case of the SXD also more toroidal field coil conductors. Boundary models with increasing degrees of complexity have been used to predict the beneficial effect of the alternative configurations on exhaust performance. While all alternative configurations should decrease the power that must be radiated in the outer divertor, only the DND and possibly the SFD also ease the radiation requirements in the inner divertor. These decreases of the radiation requirements are however expected to be small making the ability of alternative divertors to increase divertor radiation without excessive core performance degradation their main advantage. Initial 2D fluid modeling of argon seeding in XD and SFD configurations indicate such advantages over the SND, while results for SXD and DND are still pending. Additional improvements, expected from increased turbulence in the low poloidal field region of the SFD also remain to be verified. A more precise comparison with the SND as well as absolute quantitative predictions for all configurations requires more complete physics models that are currently only being developed.

Keywords: DEMO | divertor | fusion reactor | plasma exhaust

[16] Kantor R., Młynarczyk P., Kotuła J., Bocian D., Crescenzi F., Esposito B., Marocco D., Mazzone G., Brolatti G., Moro F., Centioli C., Dongiovanni D., Marzullo D., Thermo-hydraulic modeling of the ITER radial neutron camera, AIP Conference Proceedings, 2239, (2020). Abstract
X

The ITER Radial Neutron Camera (RNC) is a diagnostic system designed as a multichannel detection system to measure the uncollided neutron flux from the plasma, generated in the tokamak vacuum vessel, providing information on neutron emissivity profile. The RNC consists of array of cylindrical collimators located in two diagnostic structures: the ex-port system and the in-port system. The in-port system, contains the diamond detectors which need a temperature protection. Feasibility study of the efficiency of the cooling system for the In-port Detector Modules of the RNC during baking process was the main goal of thermo-hydraulic numerical modeling. The paper presents the concept of the cooling system layout and the original way of integration of numerical thermo-hydraulic analyses of the in-port detector cassette. Due to the large extent of the detector cassette it is impossible to include all relevant thermal and hydraulic effects in one global model with sufficient level of details. Thus the modelling strategy is based on the concept of three stage modelling from details to global model. The presented paper includes results of numerical calculations made with ANSYS Fluent software in order to provide the final answer, including calculation of heat loads in the detector cassette from adjacent walls during baking and normal operation conditions.

[17] You J.H., Villari R., Flammini D., Marzullo D., Mazzone G., Nuclear loads and nuclear shielding performance of EU DEMO divertor: A comparative neutronics evaluation of two interim design options, Nuclear Materials and Energy, 23, (2020). Abstract
X

In a demonstrational fusion power plant (DEMO), divertor is supposed to protect vacuum vessel and superconducting magnets against neutron flux in the bottom region of the vessel. The vessel is subject to a strict design limit in irradiation damage dose and the magnets in nuclear heating power, respectively. Thus, the DEMO divertor must have the capability to protect sufficiently the vessel and the magnets against neutron flux being substantially stronger than in ITER. In this paper, a first systematic neutronics study for the European DEMO divertor is reported. Results of the extensive assessment of key nuclear loading features (nuclear heating, irradiation damage & helium production) are presented for two optional concepts, namely, dome and shielding liner including minor geometrical variants. The shielding performance of the two competing design options is discussed together with the case of a bare cassette (no shielding), particularly in terms of damage dose compared with the design limits specified for the European DEMO. It was found that both the dome and shielding liner were able to significantly reduce the nuclear loads in the cassette body and the vessel. The maximum damage dose at the end of the lifetime remained subcritical for the cassette body for both cases whereas it exceeded the limit for the vessel under the dome, but only locally on the surface underneath the pumping duct. But, the damage could be reduced below the limit for the vessel by increasing the size of the dome or by deploying the shielding liner. The most critical feature was the excessive damage occurring in the own body of the shielding components where the maximum damage dose in the steel heat sink of the dome and the shielding liner far exceeded the design limit at the end of the lifetime.

Keywords: DEMO | Divertor | Neutron damage | Neutronics | Nuclear loads | Shielding | Vacuum vessel

[18] Tarallo A., Carbone F., Di Gironimo G., Coccorese D., Minopoli V., Lanzotti A., Marzullo D., d'Angelo R., An augmented and interactive AID for occupational safety, 30th European Safety and Reliability Conference, ESREL 2020 and 15th Probabilistic Safety Assessment and Management Conference, PSAM 2020, 1787-1791, (2020). Abstract
X

Most occupational safety regulations and international standards recognize the importance of keeping a corporate document that set all the safety procedures prescribed for a certain workplace. However, experience show that, to be truly effective, any piece of information must be kept updated and correctly delivered to the right recipient. From this point of view, the possibility, given by modern technology, to receive, process and send information in real time using common smartphones is a great opportunity. The authors developed a solution for mobile devices, which is based on augmented reality technologies and indoor positioning algorithms, aimed at speeding up and simplifying the information flow among safety managers, workers and casual users about safety-related content. Safety managers can use it as a support tool for the preparation of the risk assessment documentation, on the workers' side, the same application acts as an informational tool providing safety-related content when and where needed through augmented reality technologies. Preliminary results from in situ testing show that augmented reality may be a powerful tool to improve the occupational safety.

Keywords: Augmented reality | Mobile technologies | Workplace safety

[19] Tarallo A., Carbone F., Di Gironimo G., Coccorese D., Minopoli V., Lanzotti A., Marzullo D., D’angelo R., An augmented and interactive aid for occupational safety, Proceedings of the 30th European Safety and Reliability Conference and the 15th Probabilistic Safety Assessment and Management Conference, 1787-1791, (2020). Abstract
X

Most occupational safety regulations and international standards recognize the importance of keeping a corporate document that set all the safety procedures prescribed for a certain workplace. However, experience show that, to be truly effective, any piece of information must be kept updated and correctly delivered to the right recipient. From this point of view, the possibility, given by modern technology, to receive, process and send information in real time using common smartphones is a great opportunity. The authors developed a solution for mobile devices, which is based on augmented reality technologies and indoor positioning algorithms, aimed at speeding up and simplifying the information flow among safety managers, workers and casual users about safety-related content. Safety managers can use it as a support tool for the preparation of the risk assessment documentation, on the workers’ side, the same application acts as an informational tool providing safety-related content when and where needed through augmented reality technologies. Preliminary results from in situ testing show that augmented reality may be a powerful tool to improve the occupational safety.

Keywords: Augmented reality | Mobile technologies | Workplace safety

[20] Marzullo D., Di Gironimo G., Dongiovanni D.N., Lanzotti A., Mozzillo R., Tarallo A., Iterative and Participative Axiomatic Design Process to Improve Conceptual Design of Large-Scale Engineering Systems, Lecture Notes in Mechanical Engineering, 492-505, (2020). Abstract
X

This research discusses the use of a systematic design method, the Iterative and Participative Axiomatic Design Process (IPADeP), for the early conceptual design stage of large-scale engineering systems. The involvement of multiple and competing requirements has imposed high challenges for achieving an affordable design of complex systems in a reasonable lead time. Systems Engineering (SE) focuses on how to design and manage complex systems over their life cycles. Both must begin by discovering the real problems that need to be resolved and identifying from the early stage of the design the main stakeholder requirements and customer needs. The Axiomatic Design (AD) methodology is widely recognized in the literature to efficiently support the design of complex systems from the early conceptual stage. IPADeP provides a systematic methodology for applying AD theory in the conceptual design of large-scale engineering systems, aiming to minimize the risks related to the uncertainty and incompleteness of requirements and to improve the collaboration of multi-disciplinary design teams. IPADeP has been adopted as design methodology in the pre-conceptual design stage of a subsystem of the DEMOnstration fusion power plant (DEMO): the divertor cassette body-to-vacuum vessel locking system. In this paper improvements in IPADeP are presented and its validity is discussed by presenting the application to the divertor system design.

Keywords: Axiomatic Design | Design methods | Systems Engineering | Tokamak design

[21] Di Gironimo G., Marzullo D., Mozzillo R., Tarallo A., Grazioso S., The DTT device: Advances in conceptual design of vacuum vessel and cryostat structures, Fusion Engineering and Design, 146, 2483-2488, (2019). Abstract
X

In this work we present the latest progresses (September 2018) in the conceptual design of the main containment structures of DTT fusion reactor. The previous DTT baseline design is revised in terms of structural materials and overall reactor shape. The major change involves the vacuum vessel, which now foresees a welded double-wall stainless steel structure. The basic design includes eighteen sectors, with novel ports configuration for remote maintenance systems, diagnostics and heating equipment. New supports are designed for the first wall, which is conveniently segmented in view of assembly and remote replacement. The cryostat of the machine is conceived as a single-wall cylindrical vessel reinforced by ribs. The cryostat base is also in charge of supporting the vacuum vessel and the magnets system. A preliminary FEA analysis confirms that the main mechanical structure might withstand the design loads, in particular the ones resulting from possible plasma disruptions.

Keywords: CAD | DTT | EU-DEMO | FEM | Fusion reactor | Structural analysis

[22] Mazzone G., You J.H., Cerri V., Coccorese D., Garitta S., Di Gironimo G., Marzullo D., Di Maio P.A., Vallone E., Tincani A., Bonavolontà U., Imbriani V., Structural verification and manufacturing procedures of the cooling system, for DEMO divertor target (OVT), Fusion Engineering and Design, 146, 1610-1614, (2019). Abstract
X

The paper presents the design activities and testing plan of a vertical target mock-up, developed within the pre-conceptual design phase for DEMO Work Package DIV-1 “Divertor Cassette Design and Integration” - EUROfusion Power Plant Physics & Technology (PPPT) program. Activities concerning the Divertor Outboard Vertical Target cooling mock-up are presented in term of CAD model, thermal-hydraulic numerical simulation, structural analysis, structural integrity verification and manufacturing procedure. Moreover, the mechanical dimensions of support systems for Plasma Facing Components (PFCs), manifold and diffuser have been analyzed in detail, in order to avoid structural fault during the test. Test procedures are discussed, taking into account design parameters, design code and facility performances. The CuCrZr alloy selected for the PFCs of EU DEMO divertor has been used also for the mock-up, while two options are still under evaluation for manifolds/diffuser, CuCrZr and stainless Steel 316 L(N)-IG, depending on the joining technology. Since the mock-up is mainly intended to verify hydraulic performances, it has been simplified by removing the W monoblocks from its PFCs.

Keywords: DEMO | Divertor cassette | Divertor target cooling mock-up

[23] Vaccaro D., Elaian H., Reimerdes H., Baquero M., Duval B.P., Marzullo D., Moret J.M., Theiler C., Calabrò G., Di Gironimo G., Fanelli P., Minucci S., Salvitti A., Toussaint M., Thermal, electromagnetic and structural analysis of gas baffles for the TCV divertor upgrade, Fusion Engineering and Design, 146, 1543-1547, (2019). Abstract
X

As part of an ongoing divertor upgrade of the TCV tokamak it is planned to add gas baffles to form a divertor chamber of variable closure. The baffles promise to increase the compression of neutral particles in the divertor and, thereby, extend the research on the TCV divertor towards more reactor relevant, highly dissipative divertor regimes. It is foreseen to construct the baffles entirely of polycrystalline graphite that was used for the existing TCV protection tiles. The thermal considerations of the baffle design are based on the heat loads expected during normal operation, where even an extremely large increase in the power carrying plasma channel towards the baffle over the entire 2 seconds duration of a TCV discharge gives no cause for concern. An electromagnetic analysis considers halo currents flowing through the baffles, which can occur during disruptions, as a worst-case scenario. It is found that a halo current of 250 kA results in an average vertical force in the baffles of up to 950 kN/m3. The fixture of the baffle tiles to the vacuum vessel is designed for a maximum tensile stress of 31 MPa and maximum compressive stress of 60 MPa that remains a factor of two below their respective material limits. The obtained results of the thermal, electromagnetic and structural analysis thus validate the proposed baffle design.

Keywords: Divertor | Finite element analysis | Plasma facing components | TCV

[24] Marzullo D., Bachmann C., Coccorese D., Di Gironimo G., Frosi P., Mazzone G., You J.H., Progress in the pre-conceptual CAD engineering of European DEMO divertor cassette, Fusion Engineering and Design, 146, 942-945, (2019). Abstract
X

This paper presents the recent progress in the pre-conceptual design activities for the EU-DEMO divertor Cassette Body, performed in the framework of the work package “Divertor” of the EUROfusion Power Plant Physics & Technology (PPPT) program. According to Systems Engineering Principles, the divertor CAD model is reviewed, considering the updates in the DEMO configuration model presented by the Programme Management Unit (PMU) in 2017. The design parameters affected by these changes and their impact on the divertor design and on the interfaced systems are analysed. Then, the paper focuses on the integration on the new cassette geometry of the divertor sub-systems. This includes the design of a “shielding liner” for cassette body and Vacuum Vessel protection, as well as the development of the cassette body-to-Vacuum Vessel fixation system. The design activities related to these main sub-systems are discussed in detail, in terms of CAD model and thermo-mechanical calculations.

Keywords: 3D CAD modelling | Divertor | Divertor fixation system | EU-DEMO | Shielding liner

[25] Frosi P., Di Maio P.A., Marzullo D., Mazzone G., You J.H., Further improvements in the structural analysis of DEMO Divertor Cassette body and design assessment according to RCC-MRx, Fusion Engineering and Design, 138, 119-124, (2019). Abstract
X

This paper presents the enhancements related to the structural analyses of DEMO Divertor in the framework of the EUROfusion Power Plant Physics & Technology (PPPT) program. This activity started two years ago and its preliminary results were published in previous papers. It has been divided in some areas defined by the similarity of the matters they contain: the structural analysis, of utmost importance, has been preceded by a preliminary phase, like the geometry definition or the thermal and the electric-magnetic analysis for loads evaluation; then the structural analysis has been finally confirmed with further evaluations related to excessive deformation or plastic instability. This paper discusses the improvements adopted either in the preliminary analysis or in the main structural analysis. Specifically it highlights the introduction of the thermal and electro-magnetic loads application in terms of a detailed spatial distribution that is now available. More the supports have been introduced in the model and their structural behavior has been investigated considering their interaction with the cassette. The structural assessment, according to the Design and Construction Rules for Mechanical Components of Nuclear Installation (RCC-MRx), has been performed either for the cassette or for the attachments: for the former it is positive while for the latter case serious limitations have been found.

Keywords: DEMO | Divertor | FEM | RCC-MRx | Structural analysis | Thermal analysis

[26] Dongiovanni D.N., Esposito B., Marocco D., Marzullo D., Design space exploration for architecture selection: Radial Neutron Camera nuclear fusion diagnostic study case, Fusion Engineering and Design, 137, 378-389, (2018). Abstract
X

System engineering is an established methodology meant to support engineering design activities for complex systems design. Nuclear fusion devices design complexity derives from contextual presence of both a challenging operating domain requiring frontier technology and a restrictive regulation on safety or systems compatibility aspects. System engineering methodologies adapted to nuclear design environment reduce risks of late design changes related to compatibility problems emerging at integration stage. Present work describes the methodology developed for the conceptual design phase of a nuclear fusion neutronic diagnostic, the Radial Neutron Camera for ITER plant. In particular the focus is on the characterization of design intents and the structured exploration of design domain aiming at baseline architecture to be engineered in next design phase. A formal definition of design domain space in terms of architectural elements has been developed to allow the instantiation of a set of candidate options. The instantiation process was structured according to sub-system intrinsic information content and potential mutual impact. Finally, architectural options have been assessed according to a specifically defined ranking function able to integrate information characterizing the candidate architectures deriving from different domains enabling a close collaboration with stakeholders.

Keywords: Architecture selection | Design ranking | Design space | Neutron diagnostic

[27] Marzullo D., Dongiovanni D.N., You J.H., Systems engineering approach for pre-conceptual design of demo divertor, International Conference on Nuclear Engineering, Proceedings, ICONE, 5, (2018). Abstract
X

The DEMOnstration Fusion power Plant (DEMO) will be a key step towards Fusion Power Plant technology. It represents the single step to a commercial fusion power plant, in charge of demonstrating the viability of relevant technologies. Indeed, the development of tokamak sub-systems has to take into account interface, structural and functional requirements and multi-physics issues that can be completely known only during the development of the design process. This leads to difficulties to be faced during the conceptual design, mainly related to the identification of the main requirements, the change management and the sub-system integration. The Systems Engineering approach aims to support the design and management of complex systems over their life-cycles, providing a systematic approach for the definition of customer needs and required functionality from the early stage of the design, as well as for the design synthesis and the system validation and verification. Among the tokamak sub-systems, the divertor is the one devoted to power exhaust management and represents, at the same time, one of the most challenging components, in terms of materials, technologies and manufacturing. Current design activities, conducted in the in the framework of EUROfusion Consortium are in a pre-conceptual phase. Despite the early design stage, a systems engineering approach is being applied as an integrated, interdisciplinary R&D effort. The paper therefore presents the modeling effort to the conceptual design of DEMO divertor aimed at identifying both system main functions and expected behavior, given the constraints imposed from either project requirement or from current viability of technological solutions. To allow for flexibility in design needed to explore the feasibility of different solutions at this pre-conceptual stage, the impact of possible changes in high level requirement or interfaces is also investigated. This is also achieved through the allocation of the requirements to the affected components and providing efficient traceability. Therefore, the proposed modelling approach is intended to support the whole divertor conceptual design stage, allowing for requirements identification, traceability and change management.

[28] Maddaluno G., Marzullo D., Mazzitelli G., Roccella S., Di Gironimo G., Zanino R., The DTT device: Divertor solutions for alternative configurations including liquid metals, Fusion Engineering and Design, 122, 341-348, (2017). Abstract
X

One of the main objectives of the DTT project is to test many divertor designs and configurations, so that the concept of the machine could change from the initial single null (SN) configuration to other configurations such as the SnowFlake Divertor (SFD). Furthermore the design of Vacuum Vessel, ports and In-Vessel Components should take into account the application and testing of a Liquid Metal Divertor. For this reason the divertor design has been developed having in mind the possibility of easily replacing the divertor itself by remote handling.

Keywords: Divertor | DTT | Liquid metal | Remote handling

[29] Di Gironimo G., Marzullo D., Mozzillo R., Tarallo A., Villone F., The DTT device: First wall, vessel and cryostat structures, Fusion Engineering and Design, 122, 333-340, (2017). Abstract
X

This paper describes the activity addressed to the conceptual design of the first wall and the main containment structures of DTT device. The work moved from the geometrical constraints imposed by the desired plasma shape and the configuration needed for the magnetic coils. Many other design constraints have been taken into account such as remote maintainability, space reservations for diagnostic and heating equipment, etc. The basic vessel design resulted in an all-welded single-wall toroidal structure made of 18 sectors. Proper supports have been designed for the first wall, which was conveniently segmented in view of remote maintenance. This provisional model allowed evaluating the electromagnetic loads on the metallic structure of the vacuum vessel resulting from the current quench due to a plasma disruption. After a FEA mechanical assessment, which was conducted according to ASME code, INCONEL® 625 has been provisionally selected as reference material for vacuum vessel. The design principles of the cryostat were chiefly based on cost minimization and functionality; thus it was conceived as a single-wall cylindrical vessel supported by a steel frame structure. The same structure will hold the vacuum vessel and the magnets.

Keywords: 3D CAD modeling | Conceptual design | Cryostat | FEM | First wall | Mechanical analysis | Vacuum vessel

[30] Cismondi F., Agostinetti P., Aiello G., Aubert J., Bachmann C., Biel W., Boccaccini L.V., Bruschi A., Day C., Del Nevo A., Di Gironimo G., Fernandez I., Franke T., Grossetti G., Hernandez F., Iglesias D., Keep J., Lang P., Loving A., Norajitra P., Mazzone G., Marzullo D., Ploeckl B., Mozzillo R., Rapisarda D., Sonato P., Tran M.Q., Vaccaro A., Villari R., You J.H., Zeile C., Progress in EU-DEMO in-vessel components integration, Fusion Engineering and Design, 124, 562-566, (2017). Abstract
X

In the EU DEMO design (Romanelli, 2012; Federici et al., 2014), due to the large number of complex systems inside the tokamak vessel it is of vital importance to address the in-vessel integration at an early stage in the design process. In the EU DEMO design, after a first phase in which the different systems have been developed independently based on the defined baseline DEMO configuration, an effort has been made to define the interface requirements and to propose the strategies for the mechanical integration of the auxiliary heating and fuelling systems into the Vacuum Vessel and the Breeding Blanket. This work presents the options studied, the engineering solutions proposed, and the issues highlighted for the mechanical in-vessel integration of the DEMO fuelling lines, auxiliaries heating systems, and diagnostics.

Keywords: Breeding Blanket | Fuelling systems | Heating systems | In-vessel components | Vacuum Vessel

[31] You J.H., Mazzone G., Bachmann C., Coccorese D., Cocilovo V., De Meis D., Di Maio P.A., Dongiovanni D., Frosi P., Di Gironimo G., Garitta S., Mariano G., Marzullo D., Porfiri M.T., Ramogida G., Vallone E., Villari R., Zucchetti M., Progress in the initial design activities for the European DEMO divertor: Subproject “Cassette”, Fusion Engineering and Design, 124, 364-370, (2017). Abstract
X

Since 2014 preconceptual design activities for European DEMO divertor have been conducted as an integrated, interdisciplinary R&D effort in the framework of EUROfusion Consortium. Consisting of two subproject areas, ‘Cassette’ and ‘Target’, this divertor project has the objective to deliver a holistic preconceptual design concept together with the key technological solutions to materialize the design. In this paper, a brief overview on the recent results from the subproject ‘Cassette’ is presented. In this subproject, the overall cassette system is engineered based on the load analysis and specification. The preliminary studies covered multi-physical analyses of neutronic, thermal, hydraulic, electromagnetic and structural loads. In this paper, focus is put on the neutronics, thermohydraulics and electromagnetic analysis.

Keywords: Cooling | DEMO | Divertor cassette | Electromagnetic loads | Neutronics | Thermohydraulics

[32] Frosi P., Bachmann C., Di Gironimo G., Mazzone G., Marzullo D., You J.H., Structural analysis of DEMO divertor cassette body and design study based on RCC-MRx, Fusion Engineering and Design, 124, 628-632, (2017). Abstract
X

This paper refers to the activity of structural design of DEMO Divertor in the framework of the EUROfusion Consortium. The structural analysis and its preparatory assessments were carried on since a year and the first results were published in a previous paper. The Cassette Body has been examined considering the most conservatives loads (e.g. coolant pressure, volumetric nuclear heating and electro-magnetic loads) according to their latest estimates. This work is based on the design-by-analysis approach adopted in the conceptual design phase of the DEMO Divertor. This design activity has been focused on some key parameters e.g. loads, main geometric dimensions, positions of the Cassette attachments on the vacuum vessel, way of loads application to characterize the structural behavior of the Divertor Cassette. In addition to the existing 3D solid element model, a shell element model has also been developed: with this new model a parametric analysis can be done for a fast optimization. The structural assessment was done according to the Design and Construction Rules for Mechanical Components of Nuclear Installation (RCC-MRx).

Keywords: DEMO | Divertor | FEM | RCC-MRx | Structural analysis | Thermal analysis

[33] Mazzone G., Aktaa J., Bachmann C., De Meis D., Frosi P., Gaganidze E., Di Gironimo G., Mariano G., Marzullo D., Porfiri M.T., Rieth M., Villari R., You J.H., Choice of a low operating temperature for the DEMO EUROFER97 divertor cassette, Fusion Engineering and Design, 124, 655-658, (2017). Abstract
X

One of the fundamental input parameters required for the thermo hydraulic and structural design of a divertor cassette is the operation temperature range. In the current design activities to develop European DEMO divertor in the frame of EUROfusion, reduced activation steel EUROFER97 was chosen as structural material for the divertor cassette body considering its low long-term activation and superior creep and swelling resistance under neutron irradiation (You et al., 2016) [1]. For specifying an operation temperature range (i.e. cooling condition) various, often conflicting requirements have to be considered. In this article the lower limit of allowed operation temperature window is defined for EUROFER97 for structural design of DEMO divertor cassette body. The underlying rationale and supporting experimental data from a number of previous irradiation tests are also presented. The motivation of this survey study is to explore the possibility to use EUROFER97 for water-cooled divertor cassette at temperatures below 350 °C which has been regarded as limit temperature to preserve ductility under irradiation. Based on the literature data of FTTT (Fracture Toughness Transition Temperature) calibrated by Master Curve method, it is concluded that EUROFER97 at the envisaged maximum dose of 6 dpa will have to be operated above 180 °C taking the embrittlement due to helium production into account.

Keywords: DEMO | Divertor cassette | EUROFER97 | Neutron fluence

[34] Marzullo D., Bachmann C., Coccorese D., Di Gironimo G., Mazzone G., You J.H., Systems engineering approach for pre-conceptual design of DEMO divertor cassette, Fusion Engineering and Design, 124, 649-654, (2017). Abstract
X

This paper presents the pre-conceptual design activities conducted for the European DEMO divertor, focusing on cassette design and Plasma Facing Components (PFC) integration. Following the systems engineering principles, a systematic design method, the Iterative and Participative Axiomatic Design Process (IPADeP), has been adopted. Basing on Axiomatic Design, IPADeP supports the early conceptual design of complex systems. The work moved from the geometrical and interface constraints imposed by the 2015 DEMO configuration model. Then, since different materials will be used for cassette and PFCs, the divertor geometry has been developed taking into account the cooling parameters of the cassette Eurofer steel and the integration of PFCs cooling system. Accordingly, the design process led to a double wall cassette structure with internal reinforcing ribs to withstand cassette coolant pressure and three different kinds of piping schemes for PFCs with dual circuits. These three solutions differs in the feeding pipes layouts and target manifold protection and they have been proposed and evaluated considering heat flux issues, shielding problems, interface requirements with blanket and vacuum vessel and remote maintenance needs. A cassette parametric shell model has been used to perform first structural analyses of the cassette body against coolant pressure. Taking advantages of the parametric surface modelling and its linkage with Finite Element (FE) code, the cassette ribs layout and thickness has been evaluated and optimized, considering at the same time the structural strength needed to withstand the coolant parameters and the maximum stiffness required for cassette preloading and locking needs.

Keywords: DEMO | Divertor cassette | Divertor cooling | Divertor structural analysis

[35] Albanese R., Pizzuto A., Ariola M., Calabrò G., Chmielewski P., Crisanti F., Di Gironimo G., Ramogida G., Tabarés F.L., Affinito L., Anemona A., L. Apicella M., Batistoni P., Calabrò G., Cardinali A., Ceccuzzi S., Centioli C., Corato V., Costa P., Crisanti F., Cucchiaro A., Della Corte A., De Marzi G., Di Zenobio A., Fiamozzi Zignani C., Gabellieri L., Lampasi A., Maddaluno G., Maffia G., Marocco D., Mazzitelli G., Messina G., Mirizzi F., Moneti M., Muzzi L., Ravera G.L., Righetti R., Roccella S., Starace F., Tomassetti G., Tuccillo A.A., Tudisco O., Turtù S., Villari S., Viola B., Vitale V., Vlad G., Zito P., Zonca F., Bruschi A., Farina D., Figini L., Garavaglia S., Granucci G., Lontano M., Micheletti D., Nowak S., Sozzi C., Ambrosino R., Barbato L., Ciattaglia S., Coccorese D., Coccorese V., de Magistris M., P. Loschiavo V., Martone R., Marzullo D., Mastrostefano S., Minucci S., Mozzillo R., Palmaccio R., Pericoli-Ridolfini V., Pironti A., Rubinacci G., Tarallo A., Ventre S., Villone F., Maggiora R., Milanesio D., Agostinetti P., Bolzonella T., Carraro L., Fassina A., Franz P., Gaio E., Gnesotto F., Innocente P., Luchetta A., Manduchi G., Marrelli L., Martin P., Peruzzo S., Piovan R., Puiatti M.E., Spizzo G., Scarin P., Sonato P., Spolaore M., Toigo V., Valisa M., The DTT proposal. A tokamak facility to address exhaust challenges for DEMO: Introduction and executive summary, Fusion Engineering and Design, 122, 274-284, (2017). Abstract
X

As indicated in the European Fusion Roadmap, the main objective of the Divertor Tokamak Test facility (DTT) is to explore alternative power exhaust solutions for DEMO so as to mitigate the risk that the conventional divertor based on detached conditions to be tested on the ITER device cannot be extrapolated to a fusion reactor. The issues to be investigated by DTT include: • demonstrate a heat exhaust system capable of withstanding the large load of DEMO in case of inadequate radiated power fraction;• close the gaps in the exhaust area that cannot be addressed by present devices;• demonstrate that the possible (alternative or complementary) solutions (e.g., advanced divertor configurations or liquid metals) can be integrated in a DEMO device. In this paper, we describe a proposal for such a DTT, presented by ENEA in collaboration with a European team of scientists. The selection of the DTT parameters (a major radius of 2.15 m, an aspect ratio of about 3, an elongation of 1.6-1.8, a toroidal field of 6 T, and a flat top of about 100 s) has been made according to the following specifications: • edge conditions as close as possible to DEMO in terms of dimensionless parameters;• flexibility to test a wide set of divertor concepts and techniques;• compatibility with bulk plasma performance.• an upper bound of 500 M€ for the investment costs. This paper illustrates this DTT proposal showing how the basic machine parameters and concept have been selected so as to make a significant step toward the accomplishment of the power exhaust mission.

Keywords: Design | Divertor | Tokamak devices

[36] Grazioso S., Selvaggio M., Marzullo D., Di Gironimo G., Gospodarczyk M., ELIGERE: A fuzzy AHP distributed software platform for group decision making in engineering design, IEEE International Conference on Fuzzy Systems, (2017). Abstract
X

This paper presents eligere, a new open-source distributed software platform for group decision making in engineering design. It is based on the fuzzy analytical hierarchy process (fuzzy AHP), a multiple criteria decision making method used in group selection processes to rank a discrete set of alternatives with respect to some evaluation criteria. eligere is built following the paradigm of distributed cyber-physical systems. It provides several features of interest in group decision making problems: a web-application where experts express their opinion on the alternatives using the natural language, a fuzzy AHP calculation module for transforming qualitative into quantitative data, a database for collecting both the experts' answers and the results of the calculations. The resulting software platform is: distributed, interactive, multi-platform, multi-language and open-source. Eligere is a flexible cyber-physical information system useful in various multiple criteria decision making problems: in this paper we highlight its key concepts and illustrate its potential through a case study, i.e., the optimum selection of design alternatives in a robotic product design.

Keywords: Distributed information systems | Fuzzy AHP | Fuzzy sets | Multiple criteria decision making | Product design | Robotics

[37] Crisanti F., Albanese R., Granucci G., Martone R., Sonato P., Affinito L., Anemona A., L. Apicella M., Batistoni P., Calabrò G., Cardinali A., Ceccuzzi S., Centioli C., Corato V., Costa P., Cucchiaro A., Della Corte A., De Marzi G., Di Zenobio A., Fiamozzi Zignani C., Gabellieri L., Lampasi A., Maddaluno G., Maffia G., Marocco D., Mazzitelli G., Messina G., Mirizzi F., Moneti M., Muzzi L., Ravera G.L., Righetti R., Roccella S., Starace F., Tomassetti G., Tuccillo A.A., Tudisco O., Turtù S., Villari S., Viola B., Vitale V., Vlad G., Zito P., Zonca F., Bruschi A., Farina D., Figini L., Garavaglia S., Lontano M., Micheletti D., Nowak S., Sozzi C., Ambrosino R., Barbato L., Ciattaglia S., Coccorese D., Coccorese V., de Magistris M., P. Loschiavo V., Marzullo D., Mastrostefano S., Minucci S., Mozzillo R., Palmaccio R., Pericoli-Ridolfini V., Pironti A., Rubinacci G., Tarallo A., Ventre S., Villone F., Maggiora R., Milanesio D., Agostinetti P., Bolzonella T., Carraro L., Fassina A., Franz P., Gaio E., Gnesotto F., Innocente P., Luchetta A., Manduchi G., Marrelli L., Martin P., Peruzzo S., Piovan R., Puiatti M.E., Spizzo G., Scarin P., Spolaore M., Toigo V., Valisa M., Zanotto L., Gorini G., Giruzzi G., Duval B., Reimerdes H., de Baar M., Zagórski R., The Divertor Tokamak Test facility proposal: Physical requirements and reference design, Nuclear Materials and Energy, 12, 1330-1335, (2017). Abstract
X

The main goal of the Divertor Tokamak Test facility (DTT) is to explore alternative power exhaust solutions for DEMO. The principal objective is to mitigate the risk of a difficult extrapolation to fusion reactor of the conventional divertor based on detached conditions under test on ITER. The task includes several issues, as: (i) demonstrating a heat exhaust system capable of withstanding the large load of DEMO in case of inadequate radiated power fraction; (ii) closing the gaps in the exhaust area that cannot be addressed by present devices; (iii) demonstrating how the possible implemented solutions (e.g., advanced divertor configurations or liquid metals) can be integrated in a DEMO device. In view of these goals, the basic physical DTT parameters have been selected according to the following guidelines: (i) edge conditions as close as possible to DEMO in terms of dimensionless parameters; (ii) flexibility to test a wide set of divertor concepts and techniques; (iii) compatibility with bulk plasma performance; (iv) an upper bound of 500 M€ for the investment costs.

[38] Albanese R., Affinito L., Anemona A., L. Apicella M., Batistoni P., Calabrò G., Cardinali A., Ceccuzzi S., Centioli C., Corato V., Costa P., Crisanti F., Cucchiaro A., Della Corte A., De Marzi G., Di Zenobio A., Fiamozzi Zignani C., Gabellieri L., Lampasi A., Maddaluno G., Maffia G., Marocco D., Mazzitelli G., Messina G., Mirizzi F., Moneti M., Muzzi L., Ravera G.L., Righetti R., Roccella S., Starace F., Tomassetti G., Tuccillo A.A., Tudisco O., Turtù S., Villari S., Viola B., Vitale V., Vlad G., Zito P., Zonca F., Bruschi A., Farina D., Figini L., Garavaglia S., Granucci G., Lontano M., Micheletti D., Nowak S., Sozzi C., Ambrosino R., Barbato L., Ciattaglia S., Coccorese D., Coccorese V., de Magistris M., P. Loschiavo V., Martone R., Marzullo D., Mastrostefano S., Minucci S., Mozzillo R., Palmaccio R., Pericoli-Ridolfini V., Pironti A., Rubinacci G., Tarallo A., Ventre S., Villone F., Maggiora R., Milanesio D., Agostinetti P., Bolzonella T., Carraro L., Fassina A., Franz P., Gaio E., Gnesotto F., Innocente P., Luchetta A., Manduchi G., Marrelli L., Martin P., Peruzzo S., Piovan R., Puiatti M.E., Spizzo G., Scarin P., Sonato P., Spolaore M., Toigo V., Valisa M., Zanotto L., Gorini G., Giruzzi G., Duval B., Reimerdes H., de Baar M., Zagórski R., DTT: A divertor tokamak test facility for the study of the power exhaust issues in view of DEMO, Nuclear Fusion, 57(1), (2017). Abstract
X

In parallel with the programme to optimize the operation with a conventional divertor based on detached conditions to be tested on the ITER device, a project has been launched to investigate alternative power exhaust solutions for DEMO, aimed at the definition and the design of a divertor tokamak test facility (DTT). The DTT project proposal refers to a set of parameters selected so as to have edge conditions as close as possible to DEMO, while remaining compatible with DEMO bulk plasma performance in terms of dimensionless parameters and given constraints. The paper illustrates the DTT project proposal, referring to a 6 MA plasma with a major radius of 2.15 m, an aspect ratio of about 3, an elongation of 1.6-1.8, and a toroidal field of 6 T. This selection will guarantee sufficient flexibility to test a wide set of divertor concepts and techniques to cope with large heat loads, including conventional tungsten divertors; liquid metal divertors; both conventional and advanced magnetic configurations (including single null, snow flake, quasi snow flake, X divertor, double null); internal coils for strike point sweeping and control of the width of the scrape-off layer in the divertor region; and radiation control. The Poloidal Field system is planned to provide a total flux swing of more than 35 Vs, compatible with a pulse length of more than 100 s. This is compatible with the mission of studying the power exhaust problem and is obtained using superconducting coils. Particular attention is dedicated to diagnostics and control issues, especially those relevant for plasma control in the divertor region, designed to be as compatible as possible with a DEMO-like environment. The construction is expected to last about seven years, and the selection of an Italian site would be compatible with a budget of 500 M.

Keywords: divertor | plasma facing components | tokamak

[39] Mozzillo R., Tarallo A., Marzullo D., Bachmann C., Di Gironimo G., Mazzone G., Preliminary structural assessment of DEMO vacuum vessel against a vertical displacement event, Fusion Engineering and Design, 112, 244-250, (2016). Abstract
X

This paper focuses on a preliminary structural analysis of the current concept design of DEMO vacuum vessel (VV). The VV structure is checked against a vertical load due to a Vertical Displacement Event in combination with the weight force of all components that the main vessel shall bear. Different configurations for the supports are considered. Results show that the greatest safety margins are reached when the tokamak is supported through the lower ports rather than the equatorial ports, though all analyzed configurations are compliant with RCC-MRx design rules.

Keywords: DEMO vacuum vessel | Elastoplastic analysis | Finite element method (FEM)

[40] Mozzillo R., Marzullo D., Tarallo A., Bachmann C., Di Gironimo G., Development of a master model concept for DEMO vacuum vessel, Fusion Engineering and Design, 112, 497-504, (2016). Abstract
X

This paper describes the development of a master model concept of the DEMO vacuum vessel (VV) conducted within the framework of the EUROfusion Consortium. Starting from the VV space envelope defined in the DEMO baseline design 2014, the layout of the VV structure was preliminarily defined according to the design criteria provided in RCC-MRx. A surface modelling technique was adopted and efficiently linked to the finite element (FE) code to simplify future FE analyses. In view of possible changes to shape and structure during the conceptual design activities, a parametric design approach allows incorporating modifications to the model efficiently.

Keywords: CAD-FEA associativity | Conceptual design | DEMO vacuum vessel | Surface modelling

[41] Meszaros B., Shannon M., Marzullo D., Woodley C., Rowe S., Di Gironimo G., Configuration management of the EU DEMO conceptual design data, Fusion Engineering and Design, 109-111(PartB), 1619-1623, (2016). Abstract
X

The EUROfusion Consortium is setting up – as part of the EU Fusion Roadmap – the framework for the implementation of the (pre)conceptual design phase of the DEMO reactor. Configuration management needs have been identified as one of the key elements of this framework and is the topic of this paper, in particular the configuration of the CAD design data. The desire is to keep the definition and layout of the corresponding systems “light weight” and relatively easy to manage, whilst simultaneously providing a level of detail in the definition of the design configuration that is fit for the purpose of a conceptual design. This paper aims to describe the steps followed during the definition of the configuration management system of the DEMO design data in terms of (i) the identification of the appropriate product data management system, (ii) the description of the philosophy of the configuration management of the design data, and (iii) the introduction of the most important enabling processes.

Keywords: CDA | Configuration | DEMO | Design | Management

[42] You J.H., Mazzone G., Visca E., Bachmann C., Autissier E., Barrett T., Cocilovo V., Crescenzi F., Domalapally P.K., Dongiovanni D., Entler S., Federici G., Frosi P., Fursdon M., Greuner H., Hancock D., Marzullo D., McIntosh S., Müller A.V., Porfiri M.T., Ramogida G., Reiser J., Richou M., Rieth M., Rydzy A., Villari R., Widak V., Conceptual design studies for the European DEMO divertor: Rationale and first results, Fusion Engineering and Design, 109-111(PartB), 1598-1603, (2016). Abstract
X

In the European fusion roadmap, reliable power handling has been defined as one of the most critical challenges for realizing a commercially viable fusion power. In this context, the divertor is the key in-vessel component, as it is responsible for power exhaust and impurity removal for which divertor target is subjected to very high heat flux loads. To this end, an integrated R&D project was launched in the EUROfusion Consortium in order to deliver a holistic conceptual design solution together with the core technologies for the entire divertor system of a DEMO reactor. The work package ‘Divertor’ consists of two project areas: ‘Cassette design and integration’ and ‘Target development’. The essential mission of the project is to develop and verify advanced design concepts and the required technologies for a divertor system being capable of meeting the physical and system requirements defined for the next-generation European DEMO reactor. In this contribution, a brief overview is presented of the works from the first project year (2014). Focus is put on the loads specification, design boundary conditions, materials requirements, design approaches, and R&D strategy. Initial ideas and first estimates are presented.

Keywords: Conceptual design | DEMO | Divertor | Eurofusion | Plasma-facing component | Tokamak

[43] Di Gironimo G., Cacace M., Crescenzi F., Labate C., Lanzotti A., Lucca F., Marzullo D., Mozzillo R., Pagani I., Ramogida G., Roccella S., Viganò F., Innovative design for FAST divertor compatible with remote handling, electromagnetic and mechanical analyses, Fusion Engineering and Design, 98-99, 1465-1469, (2015). Abstract
X

Divertor is a crucial component in Tokamaks, aiming to exhaust the heat power and particles fluxes coming from the plasma during discharges. This paper focuses on the optimization process of FAST divertor, aimed at achieving required thermo-mechanical capabilities and the remote handling (RH) compatibility. Divertor RH system final layout has been chosen between different concept solutions proposed and analyzed within the principles of Theory of Inventive Problem Solving (TRIZ). The design was aided by kinematic simulations performed using Digital Mock-Up capabilities of Catia software. Considerable electromagnetic (EM) analysis efforts and top-down CAD approach enabled the design of a final and consistent concept, starting from a very first dimensioning for EM loads. In the final version here presented, the divertor cassette supports a set of tungsten (W) actively cooled tiles which compose the inner and outer vertical targets, facing the plasma and exhausting the main part of heat flux. W-tiles are assembled together considering a minimum gap tolerance (0.1-0.5 mm) to be mandatorily respected. Cooling channels have been re-dimensioned to optimize the geometry and the layout of coolant volume inside the cassette has been modified as well to enhance the general efficiency.

Keywords: Digital Mock-Up | Divertor | FAST | Finite element EM and mechanical analyses | Remote handling

[44] Di Gironimo G., Lanzotti A., Marzullo D., Esposito G., Carfora D., Siuko M., Iterative and Participative Axiomatic Design Process in complex mechanical assemblies: case study on fusion engineering, International Journal on Interactive Design and Manufacturing, 9(4), 325-338, (2015). Abstract
X

The present paper proposes a structured Product Development Lifecycle (PDL) model to deal with the concept design stage of complex assemblies. The proposed method provides a systematic approach to design, aimed to improve requirements management, project management and communication among stakeholders as well as to avoid project failures reducing project development time. This research also provides suggestions and recommendations for utilizing different analysis, synthesis and assessment methodologies along with the proposed approach. The process developed, named Iterative and Participative Axiomatic Design Process (IPADeP), is consistent with ISO/IEC 15288:2008 – “Systems and software engineering”, and INCOSE Systems engineering handbook. It is an iterative and incremental design process, participative and requirements driven, based on the theory of Axiomatic Product Development Lifecycle (APDL). IPADeP provides a systematic methodology in which, starting from a set of experts’ assumptions, a number of conceptual solutions are generated, analysed and evaluated. Based on the results obtained, new iterations can be performed for each level of decomposition while product requirements are refined. In this paper, we applied IPADeP to the initial phase of conceptual design activities for DEMO divertor-to-vacuum vessel locking system in order to propose new innovative solutions.

Keywords: Axiomatic Design | Concept design | DEMO divertor locking system | Fuzzy-AHP | Systems engineering

[45] Marzullo D., Di Gironimo G., Lanzotti A., Mazzone G., Mozzillo R., Design Progress of the DEMO Divertor Locking System According to IPADeP Methodology, Procedia CIRP, 34, 56-63, (2015). Abstract
X

The Iterative and Participative Axiomatic Design Process (IPADeP) deals with the early conceptual design stage of complex mechanical assemblies. It provides a systematic approach based on the theory of Axiomatic Product Development Lifecycle and aims to minimize the risks related to the uncertainty and incompleteness of the requirements, considering that the requirements will be refined and completed during the process. IPADeP has an iterative nature and is focused on the experience of the people involved in the design process. The functional requirements and the design parameters are conceived through brainstorming sessions and the concept selection is performed involving several experts through a Multi Criteria Decision Making technique. IPADeP has been adopted as methodology to address the early conceptual design stage of a subsystem of the DEMOnstration fusion power plant: the divertor cassette-to-vacuum vessel locking system. A first iteration was performed, resulting in the selection of a "high level" rough solution. According with IPADeP this paper presents an improvement of this solution, performing a new iteration of the process, since the system is ripe to proceed with the decomposition and zigzagging to the second level and new requirements are coming in from the development of the interfaced systems.

Keywords: Axiomatic Design | Conceptual Design | fusion engineering | IPADeP

[46] Di Gironimo G., Carfora D., Esposito G., Lanzotti A., Marzullo D., Siuko M., Concept design of the DEMO divertor cassette-to-vacuum vessel locking system adopting a systems engineering approach, Fusion Engineering and Design, 94(1), 72-81, (2015). Abstract
X

This paper deals with pre-concept studies of DEMO divertor cassette-to-vacuum vessel locking system under the work program WP13-DAS-07-T06: Divertor Remote Maintenance System pre-concept study. An iterative design process, consistent with Systems Engineering guidelines and named Iterative and Participative Axiomatic Design Process (IPADeP), is used in this paper to propose new innovative solutions for divertor locking system, which can overcome the difficulties in applying the ITER principles to DEMO. The solutions conceived have been analysed from the structural point of view using the software Ansys and, eventually, evaluated using the methodology known as Fuzzy-Analytic Hierarchy Process. Due to the lack and the uncertainty of the requirements in this early conceptual design stage, the aim is to cover a first iteration of an iterative and incremental process to propose an innovative design concept to be developed in more details as the information will be completed.

Keywords: Concept design | DEMO divertor locking system | FEM analysis | Fuzzy-AHP | Remote maintenance | System engineering