Search results for "Joint European Torus"
showing 6 items of 6 documents
Spectrometric analysis of inner divertor materials of JET carbon and ITER-like walls
2019
Abstract One of main reasons of the Joint European torus (JET) transformation from the carbon (JET-C) to ITER-like (JET-ILW) wall was high tritium retention of carbon. In order to compare the tritium retention, samples of analogous positions of the plasma-facing side of vertical tiles No. 3 of two campaigns: JET-C (2008–2009) and JET-ILW (2011–2012) were cut out. Temperature-programmed tritium desorption spectrometry in He + 0.1% H2 gas flow showed that JET-C sample without a tungsten coating had by a factor of >20 higher surface concentration of tritium than JET-ILW tungsten-coated sample: 4.9 × 1013 and 1.7–2.2 × 1012 T atoms/cm2 respectively. Installation of metallic plasma facing wall i…
Efficient generation of energetic ions in multi-ion plasmas by radio-frequency heating
2017
We describe a new technique for the efficient generation of high-energy ions with electromagnetic ion cyclotron waves in multi-ion plasmas. The discussed ‘three-ion’ scenarios are especially suited for strong wave absorption by a very low number of resonant ions. To observe this effect, the plasma composition has to be properly adjusted, as prescribed by theory. We demonstrate the potential of the method on the world-largest plasma magnetic confinement device, JET (Joint European Torus, Culham, UK), and the high-magnetic-field tokamak Alcator C-Mod (Cambridge, USA). The obtained results demonstrate efficient acceleration of 3He ions to high energies in dedicated hydrogen–deuterium mixtures.…
Comparison of the structure of the plasma-facing surface and tritium accumulation in beryllium tiles from JET ILW campaigns 2011-2012 and 2013-2014
2019
In this study, beryllium tiles from Joint European Torus (JET) vacuum vessel wall were analysed and compared regarding their position in the vacuum vessel and differences in the exploitation conditions during two campaigns of ITER-Like-Wall (ILW) in 2011-2012 (ILW1) and 2013-2014 (ILW2) Tritium content in beryllium samples were assessed. Two methods were used to measure tritium content in the samples - dissolution under controlled conditions and tritium thermal desorption. Prior to desorption and dissolution experiments, scanning electron microscopy and energy dispersive x-ray spectroscopy were used to study structure and chemical composition of plasma-facing-surfaces of the beryllium sampl…
Tritium retention in plasma facing materials of JET ITER-Like-Wall retrieved from the vacuum vessel in 2012 (ILW1), 2014 (ILW2) and 2016 (ILW3)
2021
Abstract ITER-Like-Wall (ILW) project has been carried out at Joint European Torus (JET) to test plasma facing materials relevant to International Thermonuclear Experimental Reactor – ITER [1]. Limiters and an upper dump plate of the vacuum vessel are made of bulk beryllium tiles, whereas for the divertor bulk tungsten and tungsten-coated carbon fibre (CFC) composite tiles are used. During the shutdowns in ILW1 (2012), ILW2 (2014) and ILW3 (2016), selected beryllium tiles were removed from the vacuum vessel. In this study, tiles from three positions were analysed, and analysis results were compared regarding both the tile position in the vacuum vessel and differences in the exploitation con…
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.
Tritium sorption and desorption from JET beryllium tiles under temperature, electron radiation and magnetic field
2008
Abstract Tritium release at annealing of samples cut from beryllium tiles exposed to D + D, D + T plasma in the Joint European Torus (JET) was investigated under 5 MeV fast-electron radiation at the dose rate 14 MGy h −1 and in a magnetic field of 1.7 T separately and simultaneously in order to evaluate possible effects of these factors. Abundances of chemical forms of tritium—molecular T 2 (44%), atomic T 0 (42%), and ionic T + (14%) and their distribution were determined in the plasma-exposed beryllium samples with lyomethods. Fast-electron radiation considerably increased the fractional tritium release at annealing by a factor of approximately 5. The magnetic field increased the fraction…