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14 pages, 8216 KiB

Open AccessArticle

Activity and Dose Rate Calculations for Joint European Torus Outer Long-Term Irradiation Station during Tritium and Second Deuterium Tritium Experiment Campaigns

by Andrius Tidikas, Gediminas Stankūnas and Simona Breidokaitė

Appl. Sci. 2024, 14(7), 2674; https://doi.org/10.3390/app14072674 - 22 Mar 2024

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Abstract

The Joint European Torus (JET) is playing an important role in preparing for the operation of the future world’s largest tokomak, ITER. In this respect, the tritium campaign (C40) and second deuterium–tritium experiment (DTE2, C41) took place in the JET during the years 2021 and 2022. In this work, a corresponding irradiation scenario was utilized for the activation calculations of eight material foils located at the JET outer long-term irradiation station (OLTIS). Neutron-induced activities and dose rates at a 30 cm distance after shutdown at specified cooling intervals were calculated with the FISPACT-II code, employing the EAF-2010 nuclear and TENDL-2021 data libraries. The Monte Carlo MCNP6.2 particle transport code equipped with the FENDL-3.1d nuclear data library was used for the calculation of the neutron flux densities. Full article

(This article belongs to the Section Energy Science and Technology)

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11 pages, 6207 KiB

Open AccessArticle

Performance Enhancement of the Polarimetric Fibre Optical Current Sensor at JET Using Polarisation Optimisation

by Andrei Gusarov, Perry Beaumont, Paula Siren and JET Contributors

Sensors 2024, 24(2), 555; https://doi.org/10.3390/s24020555 - 16 Jan 2024

Cited by 2 | Viewed by 1406

Abstract

To achieve optimal operation of the polarimetry-based FOCS, the light polarisation state at the input of the sensing fibre part must be close to a linear one. In the case of a FOCS deployed on a tokamak, the Joint European Torus (JET) in the present work, the long fibre optics link between the laser source and the sensing fibre modifies the polarisation in an unpredictable way, making it unclear which source polarisation state is to be set. A method for performing the necessary polarisation adjustment in a systematic way is proposed based on the FOCS analysis. The method requires performing data acquisition at two different input polarisations. Based on these measurements, the optimal laser source polarisation can be found. The method was experimentally verified using laboratory set-up and then successfully demonstrated with the FOCS installed at JET. Full article

(This article belongs to the Special Issue Developments and Applications of Optical Fiber Sensors)

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14 pages, 3970 KiB

Open AccessReview

Application of Ion Beam Analysis in Studies of First Wall Materials in Controlled Fusion Devices

by Marek Rubel, Anna Widdowson, Laura Dittrich, Sunwoo Moon, Armin Weckmann and Per Petersson

Physics 2022, 4(1), 37-50; https://doi.org/10.3390/physics4010004 - 17 Jan 2022

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Abstract

The paper provides a concise overview of ion beam analysis methods and procedures in studies of materials exposed to fusion plasmas in controlled fusion devices with magnetic confinement. An impact of erosion–deposition processes on the morphology of wall materials is presented. In particular, results for deuterium analyses are discussed. Underlying physics, advantages and limitations of methods are addressed. The role of wall diagnostics in studies of material migration and fuel retention is explained. A brief note on research and handling of radioactive and beryllium-contaminated materials is also given. Full article

(This article belongs to the Special Issue Selected Papers from Applied Nuclear Physics Conference 2021)

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12 pages, 7197 KiB

Open AccessFeature PaperArticle

Data for Beryllium–Hydrogen Charge Exchange in One and Two Centres Models, Relevant for Tokamak Plasmas

by Petr A. Sdvizhenskii, Inga Yu. Tolstikhina, Valery S. Lisitsa, Alexander B. Kukushkin and Sergei N. Tugarinov

Symmetry 2021, 13(1), 16; https://doi.org/10.3390/sym13010016 - 23 Dec 2020

Cited by 2 | Viewed by 2196

Abstract

Data on the cross section and kinetic rate of charge exchange (CX) between the bare beryllium nucleus, the ion Be(+4) and the neutral hydrogen atom are of great interest for visible-range high-resolution spectroscopy in the ITER tokamak because beryllium is intended as the material for the first wall in the main chamber. Here an analysis of available data is presented, and the data needs are formulated. Besides the active probe signal produced by the CX of the diagnostic hydrogen neutral beam with impurity ions in plasma, a passive signal produced by the CX of impurity ions with cold edge plasma is also important, as it shows in observation data from the JET (Joint European Torus) tokamak with an ITER-like beryllium wall. Data in the range of a few eV/amu to ~100 eV/amu (amu stands for the atomic mass unit) needed for simulations of level populations for principal and orbital quantum numbers in the emitting beryllium ions Be(+3) can be obtained with the help of two-dimensional kinetic codes. The lack of literature data, especially for data resolved in orbital quantum numbers, has instigated us to make numerical calculations with the ARSENY code. A comparison of the results obtained for the one-centre Coulomb problem using an analytic approach and for the two-centre problem using numerical simulations is presented. Full article

(This article belongs to the Special Issue Atomic Processes in Plasmas and Gases: Symmetries and Beyond)

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12 pages, 2245 KiB

Open AccessArticle

Detection of Causal Relations in Time Series Affected by Noise in Tokamaks Using Geodesic Distance on Gaussian Manifolds

by Andrea Murari, Teddy Craciunescu, Emmanuele Peluso, Michela Gelfusa and JET Contributors

Entropy 2017, 19(10), 569; https://doi.org/10.3390/e19100569 - 24 Oct 2017

Cited by 7 | Viewed by 5035

Abstract

Abstract: Modern experiments in Magnetic Confinement Nuclear Fusion can produce Gigabytes of data, mainly in form of time series. The acquired signals, composing massive databases, are typically affected by significant levels of noise. The interpretation of the time series can therefore become quite involved, particularly when tenuous causal relations have to be investigated. In the last years, synchronization experiments, to control potentially dangerous instabilities, have become a subject of intensive research. Their interpretation requires quite delicate causality analysis. In this paper, the approach of Information Geometry is applied to the problem of assessing the effectiveness of synchronization experiments on JET (Joint European Torus). In particular, the use of the Geodesic Distance on Gaussian Manifolds is shown to improve the results of advanced techniques such as Recurrent Plots and Complex Networks, when the noise level is not negligible. In cases affected by particularly high levels of noise, compromising the traditional treatments, the use of the Geodesic Distance on Gaussian Manifolds allows deriving quite encouraging results. In addition to consolidating conclusions previously quite uncertain, it has been demonstrated that the proposed approach permit to successfully analyze signals of discharges which were otherwise unusable, therefore salvaging the interpretation of those experiments. Full article

(This article belongs to the Special Issue Information Geometry II)

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