To reach fusion conditions and control the plasma configuration in ITER, the next step in tokamak fusion research, two neutral beam injectors (NBIs) will supply 17 MW each, by neutralizing accelerated negative hydrogen or deuterium ions. The requirements of ITER NBIs (40A/1MeV Dions for <=1h, 46A/870keV H- ions for <=1000s) have never been simultaneously attained. So in the Neutral Beam Test Facility (NBTF, Consorzio RFX, Italy) the operation of the full-scale ITER NBI prototype (MITICA) will be tested and optimised up to full performances, focussing on accelerator (including voltage holding), beam optics, neutralisation, residual ion removal. The NBTF includes also the full-scale prototype of the ITER NBI source with 100 keV particle energy (SPIDER), for early investigation of negative ion production and extraction, source uniformity, negative ion current density and beam optics. This contribution will describe the main results of the first two years of SPIDER operation, devoted to characterizing plasma and beam parameters, including investigation of RF-plasma coupling efficiency and magnetic filter field effectiveness in reducing co-extracted electrons. SPIDER is ready for the first caesium injection to increase negative ion density. A major shutdown, planned for 2021, to solve the issues identified during the operation and to carry out scheduled modifications, will be outlined. The installation of each MITICA power supply and auxiliary system is completed; mechanical components are under procurement by F4E. Integration. Commissioning and test of the power supplies (PS), procured by different Domestic Agencies, will be presented. In particular, 1.0 MV insulating tests were carried out step-by-step and successfully completed. In 2020 PS integrated tests on accelerator dummy load are ongoing, including the resilience to accelerator grid breakdowns using a short-circuit device in vacuum. The aggressive programme, to validate the NBI design at NBTF and to meet ITER schedule (requiring NBIs in operation in 2032), will be outlined.
On the road to ITER NBIs: SPIDER improvement after first operation and MITICA 1MV integrated power test
Toigo Vanni;
2020
Abstract
To reach fusion conditions and control the plasma configuration in ITER, the next step in tokamak fusion research, two neutral beam injectors (NBIs) will supply 17 MW each, by neutralizing accelerated negative hydrogen or deuterium ions. The requirements of ITER NBIs (40A/1MeV Dions for <=1h, 46A/870keV H- ions for <=1000s) have never been simultaneously attained. So in the Neutral Beam Test Facility (NBTF, Consorzio RFX, Italy) the operation of the full-scale ITER NBI prototype (MITICA) will be tested and optimised up to full performances, focussing on accelerator (including voltage holding), beam optics, neutralisation, residual ion removal. The NBTF includes also the full-scale prototype of the ITER NBI source with 100 keV particle energy (SPIDER), for early investigation of negative ion production and extraction, source uniformity, negative ion current density and beam optics. This contribution will describe the main results of the first two years of SPIDER operation, devoted to characterizing plasma and beam parameters, including investigation of RF-plasma coupling efficiency and magnetic filter field effectiveness in reducing co-extracted electrons. SPIDER is ready for the first caesium injection to increase negative ion density. A major shutdown, planned for 2021, to solve the issues identified during the operation and to carry out scheduled modifications, will be outlined. The installation of each MITICA power supply and auxiliary system is completed; mechanical components are under procurement by F4E. Integration. Commissioning and test of the power supplies (PS), procured by different Domestic Agencies, will be presented. In particular, 1.0 MV insulating tests were carried out step-by-step and successfully completed. In 2020 PS integrated tests on accelerator dummy load are ongoing, including the resilience to accelerator grid breakdowns using a short-circuit device in vacuum. The aggressive programme, to validate the NBI design at NBTF and to meet ITER schedule (requiring NBIs in operation in 2032), will be outlined.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
