Search results for "DIVERTOR"
showing 10 items of 63 documents
Tritija termodesorbcija no plazmas kamerā izmantotiem oglekļa šķiedras kompozīt materiāliem
2015
Darbā pētīta tritija termodifūzija no kodolsintēzes iekārtas Apvienotais Eiropas tors (Joint European Torus - JET) divu darbības kampaņu periodiem (2007-2009 un 2010-2012) ar atšķirīgu pirmās sienas konstrukciju. Tritija termodifūzija veikta plazmas skartiem vienādās divertora pozīcijās esošiem ar volframu nepārklātiem un pārklātiem ķieģeļiem un 2010. gadā savāktam vakuuma kameras putekļu un plēkšņu maisījumam. Tritija maksimālais izdalīšanās ātrums no oglekļa C-sienas konstrukcijas divertora ķieģeļiem bez volframa pārklājuma (2007-2009. gada kampaņa) ir ap 730 K. 2010.-2012. gada kampaņas ar volframu pārklātajam jeb ILW-paraugam tritija izdalīšanās maksimuma temperatūra tiek sasniegta ātrā…
JET vakuuma kameras plazmas procesu rezultātā veidojušos erozijas produktu izpēte
2017
Darbā analizēti kodolsintēzes reaktora, Apvienotā Eiropas Tora (Joint European Torus – JET) vakuuma kameras erozijas produkti. Izmantojot fizikāli ķīmiskas analīzes metodes – infrasarkanās, elektronu spinu rezonanses, Ramana, enerģijas dispersijas rentgenstaru spektrometrijas, skenējošās elektronu mikroskopijas un termodesorbcijas metodes, noteikti erozijas produktu daļiņu izmēri, ķīmisko elementu sadalījums tajās, paramagnētiskie centri un tritija izdalīšanās no erozijas produktiem, kā arī salīdzināts ar vakuumakamerā neizmantou materiālu un putekļiem no divertora ķieģeļa tilpuma. Pēc paramagnētisko centru sadalījuma erozijas produktos un divertora materiālā, spriest, ka metālu oksīdi nepi…
Thermofluid-dynamic assessment of the EU-DEMO divertor single-circuit cooling option
2023
Until 2019, the thermo-hydraulic development of the EU-DEMO divertor was based on the “double-circuit” concept, in which two independent cooling circuits served by two different Primary Heat Transfer Systems were used to cool the Plasma-Facing Components (PFC) and the Cassette Body (CB). During the Divertor Final Design Review Meeting, held in May 2020, the possibility to adopt a single cooling circuit to serve both components was suggested. This new cooling circuit was originally conceived with the aim of simplifying remote maintenance, with potential benefits for some aspects of safety and balance of plant design and integration. During the years from 2020 to 2022, in the fram…
Tritija uzkrāšanās Apvienotās Eiropas Tora volframa materiālos
2020
Darbā ir apkopota literatūra par kodolsintēzi, kā arī par nozīmīgāko tokamak tipa reaktoru – Apvienotais Eiropas Tors JET (no angļu val. Joint European Torus) un tā vakuuma kameras ITER tipa sienas (no angļu val. ITER-Like-Wall, kur ITER - Starptautiskais kodolzintēzes eksperimentālais reaktors ITER (no angļu val. International Thermonuclear Experimental Reactor))volframa materiālu. Apskatīts ir arī eksperimentālais ITER reaktors, kurš šobrīd vēl ir būvniecības stadijā. Uzsvars likts uz volframa, kā divertora materiāla, mijiedarbība ar tritiju, tā iespējamo uzkrāšanos un plazmas veidotajiem defektiem. Darba ietvaros izveidota elektroķīmiskas šķīdināšanas sistēma ar iespēju kontrolēt volfram…
Progress in the initial design activities for the European DEMO divertor: Subproject "Cassette"
2017
Abstract Since 2014 preconceptual design activities for European DEMO divertor have been conducted as an integrated, interdisciplinary R&D effort in the framework of EUROfusion Consortium. Consisting of two subproject areas, ‘Cassette’ and ‘Target’, this divertor project has the objective to deliver a holistic preconceptual design concept together with the key technological solutions to materialize the design. In this paper, a brief overview on the recent results from the subproject ‘Cassette’ is presented. In this subproject, the overall cassette system is engineered based on the load analysis and specification. The preliminary studies covered multi-physical analyses of neutronic, thermal,…
Analysis of steady state thermal-hydraulic behaviour of the DEMO Divertor cassette body cooling circuit
2017
Abstract Within the framework of the Work Package DIV 1 – “Divertor Cassette Design and Integration” of the EUROfusion action, a research campaign has been jointly carried out by ENEA and University of Palermo to investigate the thermal-hydraulic performances of the DEMO divertor cassette cooling system. A comparative evaluation study has been performed considering the two different options under consideration for the divertor cassette body coolant, namely subcooled pressurized water and helium. The research activity has been carried out following a theoretical-computational approach based on the finite volume method and adopting a qualified Computational Fluid-Dynamic (CFD) code. CFD analy…
Molecular ND Band Spectroscopy in the Divertor Region of Nitrogen Seeded JET Discharges
2018
In this contribution we present OES measurements in the JET tokamak of the deuterated NH (ND) radical and the correlation between results of those experiments and measurement of ammonia production. The observation region covers most of the divertor and its outer throat. Measurements are performed in different magnetic configurations. The results include temporal and spatial dependence of the molecular emission intensity and study of the emission band shape (vibrational and rotational temperatures) during different JET pulses, with or without nitrogen seeding. Results are a step towards the understanding of nitrogen-containing molecule creation and destruction in the divertor plasma. For com…
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…
Design optimization for the quench protection of DTT's superconducting toroidal field magnets
2021
Abstract The paper is focused on the optimal design of Fast Discharge Unit (FDU) for the quench protection of the Toroidal Field (TF) magnets of the Divertor Tokamak Test facility (DTT), an experimental facility under construction in ENEA Frascati Research Centre (Rome, Italy). The FDU is a safety key component that protects the superconducting magnets when a quench is detected through the fast extraction of the energy stored in the magnets by adding a discharge dump resistor (DR) in the TF magnets circuit. A comparison between a fixed DR and a switched variable DR has been implemented by changing resistor parameters and by using multiple current control of the power electronics components …
On the thermal-hydraulic performances of the DEMO divertor cassette body cooling circuit equipped with a liner
2020
Abstract In the framework of the Work Package DIV 1 - “Divertor Cassette Design and Integration” of the EUROfusion action, a research campaign has been jointly carried out by University of Palermo and ENEA to investigate the steady-state thermal-hydraulic performances of the DEMO divertor cassette cooling system. The research activity has been focussed onto the most recent design of the Cassette Body (CB) cooling circuit, consistent with the DEMO baseline 2017 and equipped with a liner, whose main function is to protect the underlying vacuum pump CB opening from plasma radiation. The research campaign has been carried out following a theoretical-computational approach based on the finite vo…