DTT, Divertor Tokamak Test facility, is one of the largest nuclear fusion facility under construction in Europe after ITER. Its mission is to provide an integrated nuclear fusion environment where to test power exhaust strategies useful for the first nuclear fusion power plant. It is a fully superconducting tokamak capable of confining deuterium plasmas with high flexibility with respect to shaping and strike point sweeping. Maximum plasma current of Ip = 5.5 MA and toroidal magnetic field of 6 T at the plasma center makes DTT in a position relevant for the present DEMO design. In late 2019, a consortium has been established with the aim at translating the theoretical and technological knowledge of the partners in the design, in the construction and subsequent experimental management and implementation of the Divertor Tokamak Test machine. To the DTT consortium have finally adhered ten partners representing the leading laboratories and universities involved in nuclear fusion in Italy, and the largest Italian oil company. One of the first activities concerned the development and start-up of the project coordination structure. Subsequently the Integrated Project Team started the engineering design phase with the aim at keeping the maturity of the different DTT systems and components so to guarantee the respect of the challenging schedule of construction. This effort led the DTT team to the completion of the design of the systems in critical path in late 2021 and hence to the start of procurement activities. The paper reports the main resulting final design and technical solutions for the systems of the tokamak area whose procurement activities have started or are about to start, and gives an overview of the forthcoming activities.

Plasma properties can be useful in a wide spectrum of applications. Experimental projects on controlled nuclear fusion are the most challenging of these applications and, at the same time, the best way to approach plasma science. Since nuclear fusion reactors can ensure a large-scale, safe, environmentally-friendly and virtually inexhaustible source of energy, several fusion-oriented megaprojects and innovative companies are appearing all over the world. PROTO-SPHERA (Spherical Plasma for HElicity Relaxation Assessment) is the first plasma project with a simply connected configuration, namely not requiring additional objects inside the plasma volume. This is obtained by a plasma arc, shaped as a screw pinch, acting as the centerpost of a spherical torus with minimal aspect ratio. Due to its intrinsic physical, engineering and economic advantages, this new approach is attractive also on an industrial scale and with several developments that still needs to be explored. This paper presents the PROTO-SPHERA basic principles, its first encouraging results and its expected and potential evolutions.

This paper first recalls the main characteristics, design criteria, and strong points of the ac/dc conversion system of RFX-mod. Then, after having described some innovative experimental scenarios and performance improvements which have been devised, the corresponding impact on the ac/dc conversion system and the compatibility with the present design are discussed. Some possible upgrades are identified and the pros and cons are evaluated, also through dedicated simulations.

This paper firstly recalls the main characteristics, design criteria and strong points of the ac/dc conversion system of RFX-mod. Then, after having described some innovative experimental scenarios and performance improvements which have been devised, the corresponding impact on the ac/dc conversion system and the compatibility with the present design are discussed. Some possible upgrades are identified and the pros and cons are evaluated, also through dedicated simulations.

This paper describes a conceptual design study for the circuit configuration of the Error Field Correction Coil (EFCC) power supply (PS) to maximize the expected performance with reasonable cost in JT-60SA. The EFCC consists of eighteen sector coils installed inside the vacuum vessel, six in the toroidal direction and three in the poloidal direction, each one rated for 30 kA-turn. As a result, star point connection is proposed for each group of six EFCC coils installed cyclically in the toroidal direction for decoupling with poloidal field coils. In addition, a six phase inverter which is capable of controlling each phase current was chosen as PS topology to ensure higher flexibility of operation with reasonable cost.

In order to move samples amongst different ultra-high vacuum (uhv) chambers in the laboratory, an apparatus capable of operating a sputter-ion pump for long time in the absence of its mains power supply has been designed. It consists of an electronic circuit controlling a high-voltage module which is fed by batteries. © 1993.