Injection of solid, cryogenic hydrogen isotope pellets in tokamaks is used for particle fuelling as well as for ELM control. The efficiency depends on technical control variables such as pellet size, velocity, frequency and poloidal launch position. Recently developed image processing methods have been improved and adapted in order to evaluate some of these key parameters. An optical flow method has been used for the determination of the ice extrusion

Tungsten erosion, its subsequent transport and redeposition are of great interest, because a full tungsten divertor is foreseen to be used during the deuterium–tritium operational phase of ITER. The erosion of tungsten and carbon marker layers was extensively studied in the outer divertor of ASDEX Upgrade (AUG), and work is currently in progress to completely replace the existing JET CFC tiles with tungsten-coated tiles within the JET ITER-like

Quantitative characterization of the porosity structure of the carbon reinforced carbon fibre (CFC) materials is carried out by high resolution cone-beam X-ray micro-tomography (CBmCT). It is shown that CBmCT provides useful information pertaining to the in-depth fuel migration into carbon tiles function of the CFC material structure. The investigated materials comprised two types of non-irradiated CFC samples (former ITER reference CFC NB31 and

The tangential gamma-ray spectrometer (TGRS) of the JET tokamak fusion facility is an important diagnostics for investigating the fast particle evolution. A well defined field of view for the TGRS diagnostics is essential for its proper operation and this is to be determined by a rather complex system of collimators and shields both for the neutron and gamma radiations. A conceptual design for this system has been carried out with the main design

Neutron filters/attenuators have been designed and constructed as an upgrade of the JET GammaRay Cameras (GRC’s). This diagnostics upgrade should reduce the neutron flux at the gamma-ray detectors in a way that it would make possible gamma-ray imaging measurements in high power deuterium JET pulses, and eventually in deuterium-tritium discharges. The attenuators will be placed within the GRC diagnostics system between the vacuum vessel port and

Injection of solid, cryogenic hydrogen isotope pellets in tokamaks is used for particle fuelling as well as for ELM control. The efficiency depends on technical control variables such as pellet size, velocity, frequency and poloidal launch position. Recently developed image processing methods have been improved and adapted in order to evaluate some of these key parameters. An optical flow method has been used for the determination of the ice extrusion

Notwithstanding the advances of the past decades, significant developments are still needed to satisfactorily diagnose “burning plasmas.” D–T plasmas indeed require a series of additional measurements for the optimization and control of the configuration: the 14 MeV neutrons, the isotopic composition of the main plasma, the helium ash, and the redistribution and losses of the alpha particles. Moreover a burning plasma environment is in general

The Doppler broadening of individual γ -ray lineswas measured with a high purity germanium detector in JET plasma experiments. High-resolution γ -ray spectrometry of nuclear reactions between energetic D, 3-He and 4-He ions accelerated by ion cyclotron resonance heating and main plasma impurities such as carbon and beryllium has been used. The nuclear reactions giving rise to γ -rays have been identified and an effective temperature of the heated

An optical flow method is applied to the study of several fusion plasma relevant issues, including plasma wall interactions. A multi-resolution coarse-to-fine procedure is used in order to cope with large displacements of objects between consecutive frames, characteristic of plasma images captured by JET fast visible camera. Occlusion modeling is also implemented. The method is able to provide good results for JET fast-visible camera images which

During the application, the active surface of the forging dies is subjected to intense mechanical and thermal stresses combined with chemical oxidation. The fatigue resistance is an important characteristic which limits the service lifetime of the forging tools. This characteristic was significantly improved by a combined treatment between laser alloying/dispersing and plasma nitriding. This treatment was developed for W1.2365 and W1.2344 steels