Search results for "fluids"
showing 10 items of 1936 documents
Trapping of hydrogen and helium at dislocations in tungsten: anab initiostudy
2017
Retention of plasma gas components such as hydrogen (H) isotopes and helium (He) is one of the limiting factors in selection of plasma facing materials for future thermonuclear fusion devices. Tungsten (W) is one of the promising candidates for such materials and was chosen for the divertor armor for International Thermonuclear Experimental Reactor (ITER) and the first wall material for the design of the demonstrational fusion power plant - DEMO. For the analytical estimation of accumulation of H/He components in tungsten, it is important to understand the relevant physical mechanisms of their trapping in the material and thoroughly parameterize them numerically. Experiments involving high …
Overview of the HCPB Research Activities in EUROfusion
2018
In the framework of the EUROfusion’s Power Plant Physics and Technology, the working package breeding blanket (BB) aims at investigating four different BB concepts for an EU demonstration fusion reactor (DEMO). One of these concepts is the helium-cooled pebble bed (HCPB) BB, which is based on the use of pebble beds of lithiated ternary compounds and Be or beryllides as tritium breeder and multiplier materials, respectively, EUROFER97 as structural steel and He as coolant. This paper aims at giving an overview of the EU HCPB BB Research and Development (R&D) being developed at KIT, in collaboration with Wigner-RCP, BUTE-INT, and CIEMAT. The paper gives an outline of the HCPB BB design evolut…
Demonstration of the double Penning Trap technique with a single proton
2013
Spin flips of a single proton were driven in a Penning trap with a homogeneous magnetic field. For the spin-state analysis the proton was transported into a second Penning trap with a superimposed magnetic bottle, and the continuous Stern-Gerlach effect was applied. This first demonstration of the double Penning trap technique with a single proton suggests that the antiproton magnetic moment measurement can potentially be improved by three orders of magnitude or more. Spin flips of a single proton were driven in a Penning trap with a homogeneous magnetic field. For the spin-state analysis the proton was transported into a second Penning trap with a superimposed magnetic bottle, and the cont…
Structure, tritium depth profile and desorption from 'plasma-facing' beryllium materials of ITER-Like-Wall at JET
2017
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 under grant agreement No 633053 . The views and opinions expressed herein do not necessarily reflect those of the European Commission.
Direct synthesis of pure brannerite UTi2O6
2019
International audience; A new method based on the precipitation of uranium(IV) and titanium(IV) hydroxide precursors was developed to prepare pure brannerite UTi2O6 samples. In fact, U(IV) dissolved in HCl (6 mol L−1) was mixed to Ti (IV) alkoxyde before a basification step with an excess of NH4OH to obtain a highly reactive nanometric (U,Ti)(OH)4 powder. The obtained powder was then dried under vacuum, pressed into pellets and finally fired at 1300 °C. This method led to the formation of pure brannerite in contrast to previous reported protocols, which showed the formation of impurities such us UO2 and TiO2. The refined unit cell parameters of UTi2O6 led to a = 9.8113(2) Å, b = 3.7681(1) Å…
The role of yttrium and titanium during the development of ODS ferritic steels obtained through the STARS route: TEM and XAS study
2018
Abstract Oxide Dispersion Strengthened Ferritic Steels (ODS FS) are candidate materials for structural components in future fusion reactors. Their high strength and creep resistance at elevated temperatures and their good resistance to neutron radiation damage is obtained through extremely fine microstructures containing a high density of nanometric precipitates, generally yttrium and titanium oxides. This work shows transmission electron microscopy (TEM) and extended X-ray absorption fine structure (EXAFS) characterization of Fe-14Cr-2W-0.3Ti-0.24Y ODS FS obtained by the STARS route (Surface Treatment of gas Atomized powder followed by Reactive Synthesis), an alternative method to obtain O…
Evolution of nitrogen concentration and ammonia production in N 2 -seeded H-mode discharges at ASDEX Upgrade
2019
Ammonia formation was studied in a series of dedicated nitrogen seeded H-mode discharges at ASDEX Upgrade. The evolution of ammonia formation was investigated with a reference phase before the seeding, and a long, stable flat-top nitrogen-seeded phase. It was monitored with divertor spectroscopy and analysis of the exhaust gas. The amount of the detected ammonia increased continuously over the course of five discharges with the same nitrogen seeding rate. The same trend was observed in the nitrogen density in the core plasma, as measured by charge exchange recombination spectroscopy and other signals, linked to the effects of nitrogen seeding. The results show that the rate of ammonia forma…
Overview of the DEMO staged design approach in Europe
2019
This paper describes the status of the pre-conceptual design activities in Europe to advance the technical basis of the design of a DEMOnstration Fusion Power Plant (DEMO) to come in operation around the middle of this century with the main aims of demonstrating the production of few hundred MWs of net electricity, the feasibility of operation with a closed-tritium fuel cycle, and maintenance systems capable of achieving adequate plant availability. This is expected to benefit as much as possible from the ITER experience, in terms of design, licensing, and construction. Emphasis is on an integrated design approach, based on system engineering, which provides a clear path for urgent R&D …
GYROCOMPU: Toolbox Designed for the Analysis of Gyrotron Resonators
2020
The key point of gyrotron design is the analysis of the radio frequency (RF) behavior in gyrotron resonators. This article proposes a comprehensive, user-friendly and effective gyrotron design toolbox (GYROCOMPU) based on the MATLAB platform. GYROCOMPU associates a relatively complete set of codes for gyrotron analysis and integrates them together into a graphical user interface (GUI). The solving algorithm of the cold cavity equations and self-consistent equations is improved. The solving method improvement in these calculation algorithms renders the analysis more efficient and accurate. Three typical examples of gyrotrons working in the 140-GHz TE03 mode, 42-GHz TE03 mode, and 140-GHz TE1…
Assessment of Proton Direct Ionization for the Radiation Hardness Assurance of Deep Submicron SRAMs Used in Space Applications
2021
Proton direct ionization from low-energy protons has been shown to have a potentially significant impact on the accuracy of prediction methods used to calculate the upset rates of memory devices in space applications for state-of-the-art deep sub-micron technologies. The general approach nowadays is to consider a safety margin to apply over the upset rate computed from high-energy proton and heavy ion experimental data. The data reported here present a challenge to this approach. Different upset rate prediction methods are used and compared in order to establish the impact of proton direct ionization on the total upset rate. No matter the method employed the findings suggest that proton dir…