Eggenstein-Leopoldshafen, Germany
Eggenstein-Leopoldshafen, Germany

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Dalla Palma M.,Consorzio RFX | Sartori E.,Consorzio RFX | Blatchford P.,Culham Center for Fusion Energy | Chuilon B.,Culham Center for Fusion Energy | And 10 more authors.
Fusion Engineering and Design | Year: 2015

The design of the beamline components of MITICA, the full prototype of the ITER heating neutral beam injectors, is almost finalised and technical specifications for the procurement are under preparation. These components are the gas neutraliser, the electrostatic residual ion dump, and the calorimeter. Electron dump panels are foreseen each side of the upstream end of the neutraliser to protect the cryo-panels from electrons, created by stripping and other processes, that exit the 1 MeV accelerator. As the design of the components must fulfil requirements on the beam physics, insight on physical processes is required to identify performance trade-offs and constraints. The spatial gas distribution was simulated to verify the pumping requirements with electron dump panels and local conditions for breakdown voltage. Electrostatic analyses were carried out for the insulating elements of the RID to verify the limits of the electric field intensity. Different criteria were approached to investigate the fracture behaviour of ceramics considering the manufacturing implications and extrapolating the conditions for proof testing. Severe heating conditions will be applied steadily, as the maximum pulse duration is 1 h, and cyclically so requiring to fulfil fatigue and ratcheting verifications. High heat fluxes, up to 13 MW/m2 on the calorimeter, with enhanced heat transfer in subcooled boiling conditions will occur in the actively cooled CuCr1Zr panel elements provided with twisted tapes as turbulence promoters. Special R&D activities were undertaken to support the design: manufacturing of thick twisted tapes leading to an increased cooling performance while maintaining flow rate requirements, bending of swirl tubes, verification for permanent deformations due to stress relaxation after heating of swirl tubes, double side deep drilling of 2 m long CuCr1Zr plates. © 2015 Elsevier B.V. All rights reserved.


Dalla Palma M.,Consorzio RFX | Sartori E.,Consorzio RFX | Blatchford P.,Culham Center for Fusion Energy | Chuilon B.,Culham Center for Fusion Energy | And 10 more authors.
Fusion Engineering and Design | Year: 2015

The design of the beamline components of MITICA, the full prototype of the ITER heating neutral beam injectors, is almost finalised and technical specifications for the procurement are under preparation. These components are the gas neutraliser, the electrostatic residual ion dump, and the calorimeter. Electron dump panels are foreseen each side of the upstream end of the neutraliser to protect the cryo-panels from electrons, created by stripping and other processes, that exit the 1MeV accelerator. As the design of the components must fulfil requirements on the beam physics, insight on physical processes is required to identify performance trade-offs and constraints. The spatial gas distribution was simulated to verify the pumping requirements with electron dump panels and local conditions for breakdown voltage. Electrostatic analyses were carried out for the insulating elements of the RID to verify the limits of the electric field intensity. Different criteria were approached to investigate the fracture behaviour of ceramics considering the manufacturing implications and extrapolating the conditions for proof testing. Severe heating conditions will be applied steadily, as the maximum pulse duration is 1h, and cyclically so requiring to fulfil fatigue and ratcheting verifications. High heat fluxes, up to 13MW/m2 on the calorimeter, with enhanced heat transfer in subcooled boiling conditions will occur in the actively cooled CuCr1Zr panel elements provided with twisted tapes as turbulence promoters. Special R&D activities were undertaken to support the design: manufacturing of thick twisted tapes leading to an increased cooling performance while maintaining flow rate requirements, bending of swirl tubes, verification for permanent deformations due to stress relaxation after heating of swirl tubes, double side deep drilling of 2m long CuCr1Zr plates. © 2015 Elsevier B.V.


PubMed | Institute for Technical Physics, Leibniz Institute for Solid State and Materials Research, Charles University and University of Antwerp
Type: | Journal: Scientific reports | Year: 2016

The addition of mixed double perovskite Ba2Y(Nb/Ta)O6 (BYNTO) to YBa2Cu3O(7-) (YBCO) thin films leads to a large improvement of the in-field current carrying capability. For low deposition rates, BYNTO grows as well-oriented, densely distributed nanocolumns. We achieved a pinning force density of 25 GN/m(3) at 77 K at a matching field of 2.3 T, which is among the highest values reported for YBCO. The anisotropy of the critical current density shows a complex behavior whereby additional maxima are developed at field dependent angles. This is caused by a matching effect of the magnetic fields c-axis component. The exponent N of the current-voltage characteristics (inversely proportional to the creep rate S) allows the depinning mechanism to be determined. It changes from a double-kink excitation below the matching field to pinning-potential-determined creep above it.


Schlosser M.,Institute for Technical Physics | Fischer S.,Institute for Technical Physics | Hotzel M.,Institute for Nuclear Physics | Kafer W.,Institute for Nuclear Physics
Proceedings of the International School of Physics "Enrico Fermi" | Year: 2012

The aim of the Karlsruhe Tritium Neutrino experiment (KATRIN) is the direct (model-independent) measurement of the neutrino mass. For that purpose a windowless gaseous tritium source is used, with a tritium throughput of 40 g/day. In order to reach the design sensitivity of 0.2 eV/c 2 (90% C.L.) the key parameters of the tritium source, i.e. the gas inlet rate and the gas composition, have to be stabilized and monitored at the 0.1% level (1σ). Any small change of the tritium gas composition will manifest itself in non-negligible effects on the KATRIN measurements; therefore, Laser Raman spectroscopy (LARA) is the method of choice for the monitoring of the gas composition because it is a non-invasive and fast in-line measurement technique. In this paper, the requirements of KATRIN for statistical and systematical uncertainties of this method are discussed. An overview of the current performance of the LARA system with respect to precision will be given. In addition, two complementary approaches of intensity calibration are presented. © Società Italiana di Fisica.


Brighenti F.,Institute for Technical Physics | Ramalingam R.,Institute for Technical Physics | Neumann H.,Institute for Technical Physics
IOP Conference Series: Materials Science and Engineering | Year: 2015

Wind and photovoltaic parks raise the issue of a discontinuous electrical generation. As an energy carrier with high volumetric energy density, liquid hydrogen is an inevitable choice for large-scale energy storage. But, since balancing loads or rapidly evolving fluctuations on the grid with just hydrogen is unrealistic due to its slow response, it is necessary to integrate it with an electrical energy storage device that enables rapid response. This approach combines the use of a liquefaction plant for hydrogen, and a superconducting magnetic energy storage (SMES). Besides, in this case, conventional liquefaction methods are not a viable solution, meaning that a substantial simplification of the process is possible where a regenerator/recuperator is employed and only if temporary/intermediate storage is required. A study is conducted to develop a regenerator (among other parts) for a proof of concept small scale LIQHYSMES system. A 1D model of differential equations is implemented to investigate the regenerator performances, addressing parameters such as regenerator configuration, material and fluid properties, temperature profiles, etc. Results are then analysed and discussed.


Neumann H.,Institute for Technical Physics | Mayrhofer R.,RUAG RUAG Space GmbH | Richter T.,Institute for Technical Physics
IOP Conference Series: Materials Science and Engineering | Year: 2015

Complex, non-developable surfaces require a tailored multi-layer insulation (MLI) for lowest heat load. The most experiments showing the heat transfer through MLI are performed under quasi-ideal conditions determining the principle insulation quality. But the surface to be insulated in real cryostats implies feed-throughs and other non-developable surface parts. The thermal performance of MLI is degraded significantly at cutting points. To investigate this degrading effect a LN2-filled cylinder with a diameter of 219 mm and a length of 1820 mm was insulated with MLI and the heat load was measured by means of calorimetry. In addition the heat load to an insulated cylinder with eighteen branches was measured. Both cylinders have the same surface of 1.37 m2 for a comparison of the results. This article describes the experiments with different ways of tailoring the MLI for the cylinder with branches and discusses their results. It was shown that the cutting points at the branches have a significant degrading influence on the thermal performance of MLI.


Richter T.,Institute for Technical Physics | Lietzow R.,Institute for Technical Physics
IOP Conference Series: Materials Science and Engineering | Year: 2015

The new current lead test facility CuLTKa was successfully commissioned in 2014 at the Karlsruhe Institute of Technology, Germany. Towards the end of the year the first pair of High Temperature Superconductor current leads (CL) for the Japanese tokamak JT-60SA was tested. These CL have to carry currents of up to 26 kA and are cooled with helium (He) at two different temperature levels, 4.5 K and 50 K, respectively. After commissioning and test of the first pair another 24 CL will be tested until 2017. The facility consists of five cryostats: The first cryostat distributes the He coming from the 2 kW refrigerator to the different experiments in the ITEP. In the second one, with an integrated He-bath, the forced flow He for the CL is cooled down to 4.4 K and the 50 K He is piped through. In a valve box the He at two temperature levels is distributed to two test cryostats housing each one pair of CL. This paper describes the design of the facility from a cryogenic point of view starting from the basic demands. The overall setup is derived and particular details are explained. Some design calculations will be opposed to measured data from its real performance. In addition one major safety aspect is described.


Fietz W.H.,Institute for Technical Physics | Fink S.,Institute for Technical Physics | Lange C.,Institute for Technical Physics | Noe M.,Institute for Technical Physics | Winkler A.,Institute for Technical Physics
IEEE Transactions on Applied Superconductivity | Year: 2012

Magnets show a linear voltage distribution along the windings for slow changing currents. This simple behavior may be lost when fast transients occur, e.g. for fast discharge or earth fault events. Such transients may become critical with respect to the magnet lifetime if they are not considered in design and acceptance tests. The problem of internal transient over-voltages can become more essential for large magnets with high number of turns because the critical frequencies for transients are lowered due to the large number of capacitances and inductances of windings and winding packs. At KIT large fusion magnets such as POLO and the ITER Toroidal Field Model coil (TFMC) have been investigated in the large coil testing facility TOSKA. For these coils direct measurements of internal over-voltages were possible and could be compared to calculations of transient voltages. As a consequence a set of transient voltage calculations was executed at KIT for ITER coils. An overview of calculations and results for ITER TF and PF coils is given and consequences for high voltage testing are discussed. © 2011 IEEE.


Ionete E.I.,National RandD Institute for Cryogenics and Isotopic Technologies | Monea B.,National RandD Institute for Cryogenics and Isotopic Technologies | Plusczyk C.,Institute for Technical Physics | Ionete R.E.,National RandD Institute for Cryogenics and Isotopic Technologies
Fusion Engineering and Design | Year: 2013

This paper conducts an experiment and a three-dimensional (3D) modeling study for the absorption of hydrogen and deuterium on a storage tank with titanium sponge bed in order to simulate the real working conditions of a tritium storage system prior to tritium service. The 3D model is further numerically implemented and experimentally validated. The model is composed of an energy balance, mass balance and momentum balance and hydriding reaction kinetics. These differential equations are solved using finite element method. The experimental consisting in absorption of hydrogen and deuterium gas was made in batch made, under vacuum condition. Before absorption, an activation of the titanium bed was performed. A number of loading and releasing operations typically required in tritium handling loops were conducted using one bed containing a well determined quantity of titanium sponge. A comparison between theoretical results and experimental data has found that the gas was not uniformly absorbed on the metal bed volume. This work provides an important platform to understand the phenomena during tritium absorption on a titanium storage bed and the development of a real-time tritium storage control system. © 2013 Elsevier B.V.


Haas H.,Institute for Technical Physics | Day Chr.,Institute for Technical Physics | Herzog F.,Messer Group GmbH
AIP Conference Proceedings | Year: 2012

The Karlsruhe Institute of Technology (KIT) has been carrying out research and development in the field of vacuum cryopumps for nuclear fusion devices over the last decade. Together with the development activities also experience in the operation of the needed cryogenic systems necessary for such type of large scale cryopumps was collected. Due to the specific requirements of a large fusion device, such as ITER, the cryogenic distribution is based on gaseous helium at the needed temperature levels rather than liquid nitrogen or liquid helium. KIT has set up a large scale research facility, called TIMO-2, fully equipped with supercritical helium supply at large flow rates to be able to perform cryogenic tests of components under ITER-relevant conditions. During first test campaigns at TIMO-2 with a large scale model cryopump the ITER cryosorption vacuum pumping concept was successfully validated. After major refurbishments and upgrades, the TIMO-2 facility is now ready for the acceptance tests of the ITER torus cryopump. This paper describes the modified test facility TIMO-2 with particular attention to the available cryogenic supply at different temperature levels. The new 100 K helium supply facility will be described in detail. © 2012 American Institute of Physics.

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