Coils and power supplies design for the SMART tokamak

Agredano-Torres, M., et al.A new spherical tokamak, the SMall Aspect Ratio Tokamak (SMART), is currently being designed at the University of Seville. The goal of the machine is to achieve a toroidal field of 1 T, a plasma current of 500 kA and a pulse length of 500 ms for a plasma with a major radius of 0.4 m and minor radius of 0.25 m. This contribution presents the design of the coils and power supplies of the machine. The design foresees a central solenoid, 12 toroidal field coils and 8 poloidal field coils. Taking the current waveforms for these set of coils as starting point, each of them has been designed to withstand the Joule heating during the tokamak operation time. An analytical thermal model is employed to obtain the cross sections of each coil and, finally, their dimensions and parameters. The design of flexible and modular power supplies, based on IGBTs and supercapacitors, is presented. The topologies and control strategy of the power supplies are explained, together with a model in MATLAB Simulink to simulate the power supplies performance, proving their feasibility before the construction of the system.This work received funding from the Fondo Europeo de Desarollo Regional (FEDER) by the European Commission under grant agreement numbers IE17-5670 and US-15570. Furthermore, it has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014–2018 and 2019–2020 under grant agreement no. 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission

Magnetic equilibrium design for the SMART tokamak

The SMall Aspect Ratio Tokamak (SMART) device is a new compact (plasma major radius R≥0.40 m, minor radius a≥0.20 m, aspect ratio A≥1.7) spherical tokamak, currently in development at the University of Seville. The SMART device has been designed to achieve a magnetic field at the plasma center of up to B=1.0 T with plasma currents up to I=500 kA and a pulse length up to τ=500 ms. A wide range of plasma shaping configurations are envisaged, including triangularities between −0.50≤δ≤0.50 and elongations of κ≤2.25. Control of plasma shaping is achieved through four axially variable poloidal field coils (PF), and four fixed divertor (Div) coils, nominally allowing operation in lower-single null, upper-single null and double-null configurations. This work examines phase 2 of the SMART device, presenting a baseline reference equilibrium and two highly-shaped triangular equilibria. The relevant PF and Div coil current waveforms are also presented. Equilibria are obtained via an axisymmetric Grad-Shafranov force balance solver (Fiesta), in combination with a circuit equation rigid current displacement model (RZIp) to obtain time-resolved vessel and plasma currents.The authors would like to thank the VEST team for their technical and engineering support. This work received funding from the Fondo Europeo de Desarollo Regional (FEDER) by the European Commission under grant agreement numbers IE17-5670 and US-15570. In addition support from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No. 805162) is gratefully acknowledged

Mechanical and electromagnetic design of the vacuum vessel of the SMART tokamak

The SMall Aspect Ratio Tokamak (SMART) is a new spherical device that is currently being designed at the University of Seville. SMART is a compact machine with a plasma major radius (R) greater than 0.4 m, plasma minor radius (a) greater than 0.2 m, an aspect ratio (A) over than 1.7 and an elongation (k) of more than 2. It will be equipped with 4 poloidal field coils, 4 divertor field coils, 12 toroidal field coils and a central solenoid. The heating system comprises of a Neutral Beam Injector (NBI) of 600 kW and an Electron Cyclotron Resonance Heating (ECRH) of 6 kW for pre-ionization. SMART has been designed for a plasma current (I) of 500 kA, a toroidal magnetic field (B) of 1 T and a pulse length of 500 ms preserving the compactness of the machine. The free boundary equilibrium solver code FIESTA [1] coupled to the linear time independent, rigid plasma model RZIP [2] has been used to calculate the target equilibria taking into account the physics goals, the required plasma parameters, vacuum vessel structures and power supply requirements. We present here the final design of the SMART vacuum vessel together with the Finite Element Model (FEM) analysis carried out to ensure that the tokamak vessel provides high quality vacuum and plasma performance withstanding the electromagnetic j×B loads caused by the interaction between the eddy currents induced in the vessel itself and the surrounding magnetic fields. A parametric model has been set up for the topological optimization of the vessel where the thickness of the wall has been locally adapted to the expected forces. An overview of the new machine is presented here.This work received funding from the Fondo Europeo de Desarollo Regional (FEDER) by the European Commission under grant agreement numbers IE17-5670 and US-15570. This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014-2018 and 2019-2020 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission

Experimental confirmation of efficient island divertor operation and successful neoclassical transport optimization in Wendelstein 7-X

We present recent highlights from the most recent operation phases of Wendelstein 7-X, the most advanced stellarator in the world. Stable detachment with good particle exhaust, low impurity content, and energy confinement times exceeding 100 ms, have been maintained for tens of seconds. Pellet fueling allows for plasma phases with reduced ion-temperature-gradient turbulence, and during such phases, the overall confinement is so good (energy confinement times often exceeding 200 ms) that the attained density and temperature profiles would not have been possible in less optimized devices, since they would have had neoclassical transport losses exceeding the heating applied in W7-X. This provides proof that the reduction of neoclassical transport through magnetic field optimization is successful. W7-X plasmas generally show good impurity screening and high plasma purity, but there is evidence of longer impurity confinement times during turbulence-suppressed phases.EC/H2020/633053/EU/Implementation of activities described in the Roadmap to Fusion during Horizon 2020 through a Joint programme of the members of the EUROfusion consortium/ EUROfusio

Single and double null equilibria in the SMART Tokamak

© 2021 IOP Publishing LtdThe SMall Aspect Ratio Tokamak (SMART) device is a novel, compact (Rgeo = 0.42 m, a = 0.22 m, A 1.70) spherical tokamak, currently under development at the University of Seville. The SMART device is being developed over 3 phases, with target on-axis toroidal magnetic fields between 0.1 ≼ Bf ≼ 1.0 T, and target plasma currents of between 35 ≼ Ip ≼ 400 kA; with phases 2 and 3 enabling access to a wide range of elongations (κ ≼ 2.30) and triangularities (− 0.50 ≼ δ ≼ 0.50). SMART employs four internal divertor coils with two internal and two external poloidal field coils, enabling operation in lower-single, upper-single and double-null configurations. This work examines phase 3 of the SMART device, presenting a prospective L-mode discharge scenario without external heating, before examining five highly-shaped equilibria, including: two double null triangular configurations, two single null triangular configurations and a baseline double null configuration. All equilibria are obtained via an axisymmetric Grad-Shafranov force balance solver (Fiesta), in combination with a circuit equation rigid current displacement model (RZIp) to obtain time-resolved vessel and plasma currents.N

Single and double null equilibria in the SMART Tokamak

The SMall Aspect Ratio Tokamak (SMART) device is a novel, compact (R = 0.42 m, a = 0.22 m, A 1.70) spherical tokamak, currently under development at the University of Seville. The SMART device is being developed over 3 phases, with target on-axis toroidal magnetic fields between 0.1 ≼ B ≼ 1.0 T, and target plasma currents of between 35 ≼ I ≼ 400 kA; with phases 2 and 3 enabling access to a wide range of elongations (κ ≼ 2.30) and triangularities (− 0.50 ≼ δ ≼ 0.50). SMART employs four internal divertor coils with two internal and two external poloidal field coils, enabling operation in lower-single, upper-single and double-null configurations. This work examines phase 3 of the SMART device, presenting a prospective L-mode discharge scenario without external heating, before examining five highly-shaped equilibria, including: two double null triangular configurations, two single null triangular configurations and a baseline double null configuration. All equilibria are obtained via an axisymmetric Grad-Shafranov force balance solver (Fiesta), in combination with a circuit equation rigid current displacement model (RZIp) to obtain time-resolved vessel and plasma currents.The authors would like to thank the VEST team for their technical and engineering support. This work received funding from the Fondo Europeo de Desarollo Regional (FEDER) by the European Commission under grant agreement numbers IE17-5670 and US-15570. In addition support from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No. 805 162) is gratefully acknowledged

Gestión de los residuos sanitarios en el ámbito hospitalario. Nivel de conocimiento y valoración global

Los residuos sanitarios representan un peligro potencial para los trabajadores sanitarios. Dado el alto riesgo de infección en los accidentes laborales, la gestión correcta de los residuos sanitarios minimiza el riesgo y mejora las condiciones labora­les y ambientales. OBJETIVOS. Identificar el nivel de conocimiento que tienen los profesionales sanitarios, en relación con la clasificación y ges­tión avanzada de los residuos sanitarios (RS) y valorar de for­ma global la gestión de los mismos. METODOLOGÍA. Estudio descriptivo transversal con 178 partici­pantes (auxiliares, enfermeras, médicos y técnicos de labora­torio), de 3 hospitales de la provincia de Barcelona. Se utilizó un cuestionario de elaboración propia, que anali­zaba las variables laborales, el conocimiento y la valoración global de la gestión de los RS. RESULTADOS. El nivel medio de conocimiento sobre los RS de los auxiliares, las enfermeras, los médicos y los técnicos de laboratorio, en una escala de 1 (valor mínimo) a 15 (valor máximo), es de 10.59, 10.61, 8.92 y 8.39, respectivamente. La valoración global que hacen los auxiliares, las enfermeras, los médicos y los técnicos de laboratorio de la gestión de los RS en una escala de 1 (valor mínimo) y 5 (valor máximo), es de 2.89, 2.93, 2.88, 2.94, respectivamente. C0NCLUSI0NES. Los resultados sugieren que las enfermeras y los auxiliares tienen un nivel de conocimiento aceptable con res­pecto a la gestión correcta de los RS. En cambio, los médicos y técnicos de laboratorio tienen un nivel de conocimiento infe­rior sobre la segregación y eliminación adecuada de los RS. En cuanto a la valoración global, se obtienen valores aceptables, y muy similares, entre las diferentes categorías de profesiona­les estudiadas, en relación con la gestión correcta de los RS en los centros asistenciales donde realizan su actividad laboral