Search results for "KAM"

Confirmation of the topology of the Wendelstein 7-X magnetic field to better than 1:100,000

2016

Fusion energy research has in the past 40 years focused primarily on the tokamak concept, but recent advances in plasma theory and computational power have led to renewed interest in stellarators. The largest and most sophisticated stellarator in the world, Wendelstein 7-X (W7-X), has just started operation, with the aim to show that the earlier weaknesses of this concept have been addressed successfully, and that the intrinsic advantages of the concept persist, also at plasma parameters approaching those of a future fusion power plant. Here we show the first physics results, obtained before plasma operation: that the carefully tailored topology of nested magnetic surfaces needed for good c…

Integration of DEMO hazard piping into the tokamak building

2021

Abstract Because of the complexity of the design of a Fusion Power Plant like the EU DEMOnstration power plant the study of the plant layout must proceed in parallel with the design of the major systems. This is necessary to ensure that the design of the plant incorporates from the very beginning sound considerations on: • Safety and licensing, • Personnel security in context with operation and maintenance, • Adequate plant availability, and • Safe performance operation including delivery of few hundred MW net electric power to the electrical grid. Though it is a process of trial and change that follows the design evolution, this approach allows a better and continuous control of the numero…

Modelling of combined ICRF and NBI heating in JET hybrid plasmas

2017

During the 2015-2016 JET campaigns many efforts have been devoted to the exploration of high performance plasma scenarios envisaged for ITER operation. In this paper we model the combined ICRF+NBI heating in selected key hybrid discharges using PION. The antenna frequency was tuned to match the cyclotron frequency of minority hydrogen (H) at the center of the tokamak coinciding with the second harmonic cyclotron resonance of deuterium. The modelling takes into account the synergy between ICRF and NBI heating through the second harmonic cyclotron resonance of deuterium beam ions which allows us to assess its impact on the neutron rate RNT. We evaluate the influence of H concentration which w…

The Role of Combined ICRF and NBI Heating in JET Hybrid Plasmas in Quest for High D-T Fusion Yield

2017

Combined ICRF and NBI heating played a key role in achieving the world-record fusion yield in the first deuterium-tritium campaign at the JET tokamak in 1997. The current plans for JET include new experiments with deuterium-tritium (D-T) plasmas with more ITER-like conditions given the recently installed ITER-like wall (ILW). In the 2015-2016 campaigns, significant efforts have been devoted to the development of high-performance plasma scenarios compatible with ILW in preparation of the forthcoming D-T campaign. Good progress was made in both the inductive (baseline) and the hybrid scenario: a new record JET ILW fusion yield with a significantly extended duration of the high-performance pha…

Conceptual Design and Modeling of the Toroidal Field Coils Circuit of DTT

2020

Italian Divertor Tokamak Test (DTT) facility is part of the general European programme on the fusion research. Its specific role is to cover the gap on the power exhaust for the future DEMOstration power plant (DEMO). This tokamak will be built and installed in Italy at Frascati ENEA laboratories. The paper describes the Toroidal Field (TF) coils circuit powered by a TF power supply that feeds in series 18 toroidal superconducting magnets and the development of three software models in order to validate the adopted technical solutions in term of maximum voltage and maximum current stress on each power device/component, due to both the operating and fault conditions, and across TF coils.

Progress of the conceptual design of the European DEMO breeding blanket, tritium extraction and coolant purification systems

2020

Abstract In the frame of the EUROfusion consortium activities the Helium Cooled Pebble Bed (HCPB) and the Water Cooled Lithium Lead (WCLL) concepts are being developed as possible candidates to become driver Breeding Blanket (BB) for the EU DEMO, which aims at the tritium self-sufficiency and net electricity production. The two BB design options encompass water or helium as coolants and solid ceramic with beryllium/beryllides or PbLi as tritium breeder and neutron multipliers. The BB segments have evolved towards a more stable conceptual design taking into account multiple feasibility aspects and requirements imposed by interfacing systems. Possible solutions to improve shielding capabiliti…

Status of EU DEMO heat transport and power conversion systems

2018

Abstract DEMO in Europe is considered to be the nearest-term reactor design to follow ITER and capable of demonstrating production of electricity, operating with a closed fuel-cycle and to be a facilitating machine between ITER and a commercial reactor. The aim of this paper is to show the design progress of the complex system’s “chain” devoted to the extraction of the plasma generated pulsed thermal power and its conversion into electricity delivered to the grid, including the Primary Heat Transport System (PHTS), the Power Conversion System (PCS) and the Intermediate Heat Transport System (IHTS) – provided by an Energy Storage System (ESS) – in between PHTS and PCS, which is introduced fo…

Connection between temperature, larval production, virulence and geographical distribution of Rhipidocotyle parasites infecting the duck mussel, Anod…

2015

In this thesis, two bucephalid trematode parasites Rhipidocotyle campanula and R. fennica, which use the same first (Anodonta anatina) and second intermediate (Rutilus rutilus) host were studied. The aim was to investigate the effect of temperature on one of the key processes in the transmission of these parasites: 1) the emergence of cercarial larvae from A. anatina over short (1 h) and 2) long (throughout the annual cercarial shedding period, from May to October) time periods as well, as on 3) mussel survival and 4) the seasonal timing of cercarial release. In addition, the aim was to study how the cercarial shedding traits are linked to the 5) geographical occurrence and abundance of the…

Health care financing through micro insurance in Cameroon : a prelude to Universalism

2014

Aptiekā pieejamie D vitamīna uztura bagātinātāji, to lietošana atkarībā no sezonas, to cenu ietekme uz preparātu izvēli

2022

D vitamīna deficīts joprojām ir aktuāls visā pasaulē, it īpaši tas skar valstis, kuras atrodas Ziemeļu platuma grādos, kas skaidrojams ar samazinātu ultravioleto starojumu, kaut arī tas nebūt nav vienīgais faktors, kas ietekmē D vitamīna sintēzi cilvēka organismā. Neskatoties uz plašo D vitamīna uztura bagātinātāju klāstu, cilvēku informētību par tā lietošanas ieguvumiem, vēl arvien ir vērojams D vitamīna deficīts visās vecuma grupās. Ir zināms, ka D vitamīns labvēlīgi ietekmē kaulu veselību, kā arī ir saistīts ar dažu citu slimību patoģenēzi, kas plašāk ir izklāstītas šajā darbā. Darba mērķi bija veikt aptauju un noskaidrot iedzīvotāju lietošanas paradumus un biežumu atkarībā no sezonas sa…