•Status of MITICA facility.•SPIDER experimentation started.•First scan of plasma light and spectroscopic signals vs RF power and filter field.•SPIDER short-term planning.
To reach fusion conditions ...and control plasma configuration in ITER, a suitable combination of additional heating and current drive systems is necessary. Among them, two Neutral Beam Injectors (NBI) will provide 33 MW hydrogen/deuterium particles electrostatically accelerated to 1 MeV; efficient gas-cell neutralisation at such beam energy requires negative ions, obtained by caesium-catalysed surface conversion of atoms inside the ion source. As ITER NBI requirements have never been simultaneously attained, a Neutral Beam Test Facility (NBTF) was set up at Consorzio RFX (Italy), including two experiments. MITICA is the full-scale NBI prototype with 1 MeV particle energy. SPIDER, with 100 keV particle energy, aims at testing and optimising the full-scale ion source: extracted beam uniformity, negative ion current density (for one hour) and beam optics (beam divergence <7 mrad; beam aiming direction within 2 mrad). This paper outlines the worldwide effort towards the ITER NBI realisation: the main results of the ELISE facility (IPP-Garching, Germany), equipped with a half-size source, are described along with the status of MITICA; specific issues are investigated by small specific facilities and by joint experiments at QST and NIFS (Japan). The SPIDER experiment, just come into operation, will profit from strong modelling activities, to simulate and interpret experimental scenarios, and from advanced diagnostic instruments, providing thorough plasma and beam characterisation. Finally, the results of the first experiments in SPIDER are presented, aimed at a preliminary source plasma characterisation by plasma light detectors and plasma spectroscopy.
The ITER Neutral Beam Test Facility, in an advanced stage of construction in Padova, includes the installation, tests, and optimization of the full prototype of the ITER Heating Neutral Beams ...injector (HNBs), named MITICA.
The MITICA Neutral Beam Injector will host its main components in a SS304L vacuum vessel composed of two modules, connected between them on site: the Beam Source Vessel (cubic shape of 5 m side and 67 tons weight) containing the Beam Source and the Beam Line Vessel (section 4.5 m x 4.5 m, length 11 m and 76 tons weight) containing the Beam Line Components and the Cryopumps.
The manufacturing is described, going through the FE analyses performed to assess the structural integrity, the materials selection, the welding qualifications, the implementation of the double barrier sealings and the control of the deformations. The Factory Acceptance Tests of the individual vessels are presented, including their Helium Leak Tests.
The two vessels have been assembled on-site inside the MITICA bio-shield. The main outcomes of on-site final assembly and Site Acceptance Tests are described.
Both the vessels have been detail designed, manufactured, installed and tested by De Pretto Industried, from Schio, (VI) Italy, supporting fusion technology’s applications from more than 50 years. The design and the technical support were provided by Consorzio RFXa, while the procurement was managed by Fusion For Energye.
Following the allocation of the procurement of the diagnostic neutral beam (DNB) to the Indian DA, a series of tasks have been undertaken to first assess the DNB configuration and arrive at an ...optimal beam-line configuration folding in the gas-feed and vacuum-pumping requirements. Specific emphasis is placed on the thermal, structural, and electrical designs of beam-line components, in order to ensure their compatibility with the criteria specified for ITER in vessel components, i.e., Structural Design Criteria for In-Vessel Components. The detailed assessment of manufacturing technologies and their compatibility with the ITER standards forms an integral part of the design. A common approach to manufacturing for DNB and heating-and-current-drive NB components shall be undertaken through a comprehensive prototyping phase which shall lead to built-to-print specifications. In addition to safety and remote-handling issues, the design also addresses the requirements of interfaces related to other systems such as cryo, hydraulic, pneumatic, vacuum pumping, gas feed, civil, power supplies and transmission, CODAC, etc. The successful delivery of DNB is dependent on two critical R&D aspects: 1) the production of a uniform low-divergence beam from the beam source and 2) a well-controlled transmission through lengths of ~ 22 m. The first shall primarily be a subject of the Ion Source Test Facility-SPIDER part of NB test facility (MITICA in Padova)-where India is involved as a collaborator and the Indian test bed, where issues for DNB beam source which were not resolved in the SPIDER would be taken up. The second shall form one of the primary objectives of the Indian test bed to characterize the DNB. This paper presents the progress in DNB from the concept level to an engineered system along with the plans for system integration and an R&D intensive implementation.
Thermal fatigue damage of Cu–Cr–Zr alloys Chatterjee, Arya; Mitra, R.; Chakraborty, A.K. ...
Journal of nuclear materials,
11/2013, Letnik:
443, Številka:
1-3
Journal Article
Recenzirano
•This is a pioneering study of thermal fatigue damage (TFD) in aged Cu–Cr–Zr alloys.•Among various parameters, conductivity and elastic modulus sensitively reveal TFD.•Finer precipitates cause higher ...TFD in this alloy when aged at 480°C than at 500°C.•Mechanism of TFD for Cu–Cr–Zr alloys used for ITER has been described.
The primary aim of this investigation is to examine thermal fatigue damage (TFD) in Cu–Cr–Zr alloys used in High Heat Flux components of Tokamak and its subsystems. Thermal fatigue experiments have been carried out between 290°C and 30°C, which is analogous to the condition of service application on two Cu–Cr–Zr alloys having different aging treatments. The extents of TFD have been examined by standard measurements of electrical conductivity, lattice strain, residual stress and dynamic elastic modulus, supplemented by characterizations of microstructure and determination of hardness and tensile properties. The results lead to infer that the relative amounts of damage are different in the two alloys which are further dependent on their aging conditions; the reasons for the observed difference have been explained. The operative mechanisms of TFD are revealed to be as formation and subsequent coalescence of microvoids, and/or initiation and growth of microcracks.
High Voltage Bushing (HVB) is the key component of Diagnostic Neutral Beam (DNB) system of ITER as it provides access to high voltage electrical, hydraulic, gas and diagnostic feedlines to the beam ...source with isolation from grounded vessel. HVB also provides primary vacuum confinement for the DNB system. Being Safety Important Class (SIC) component of ITER, it involves several configurational, technological and operational challenges. To ensure its operational performance & reliability, particularly electrostatic behavior, half scale down Prototype High Voltage Bushing (PHVB) is designed considering same design criteria of DNB HVB. Design optimization has been carried out followed by finite element (FE) analysis to obtain DNB HVB equivalent electric stress on different parts of PHVB, taking into account all design, manufacturing & space constraints. PHVB was tested up to 60kV without breakdown, which validates its design for the envisaged operation of 50kV DC. This paper presents the design of PHVB, FEA validation, manufacturing constraints, experimental layout with interfacing auxiliary systems and operational results related to functional performance.
The accelerator for the Diagnostics Neutral Beam (DNB) beam source is composed of a multi-aperture grid system with three water cooled grids made from Oxygen free Copper. To achieve the focusing ...requirements at the distance of >20m, the grid segments are designed with two stage angles (0.222° and 0.665°) from the centerline in the horizontal direction. The configuration of this kind of ‘angled segment’ includes the water cooling channels milled in the angular form, subsequently closed by copper electrodeposition, providing the angles on front and back surface and then drilling of apertures on the angular plane. The long beam path and low energy beam demands the tight tolerances on each of these mechanical features and therefore demands the high degree of manufacturing controls on each of the processes.
To unveil the challenges those could appear during the production of such grid, a 1:1 prototype of the most complex type of grid has been manufactured. This paper shall present the technical data generated out of manufacturing of this prototype, summarizing the recommendations for real grid production on: optimization of the sequence of manufacturing, effect of each of the operations, post-manufacturing handling and identifying the measurement techniques. The experience gathered here provides a recipe for the best manufacturing practices for the accelerators of NB system for ITER and upcoming devices.
Indian Test Blanket Module (TBM) program in ITER is one of the major steps in its fusion reactor program towards DEMO and future Fusion Power Reactor (FPR) vision. Along with the DEMO machine design, ...liquid type and solid type breeding blankets are being developed for testing in ITER. India has proposed Lead–Lithium cooled Ceramic Breeder (LLCB) as the blanket concept for its DEMO reactor. The LLCB blanket concept consists of lithium titanate as ceramic breeder (CB) material in the form of packed pebble beds and Pb–Li eutectic as multiplier, breeder, and coolant for the CB zones. The outer box is cooled by helium. An alternative blanket concept also being considered for the development is the Helium-Cooled Solid Breeder (HCSB) concept with ferritic steel structure and Be neutron multiplier. Presently the primary focus is on the design and analysis of the LLCB TBM to assess the performance of LLCB concept for DEMO relevance. The LLCB TBM will be tested from day 1 operation of ITER in one-half of a designated test port. The tests in ITER include the simultaneous function of all subsystems including the TBM as well as its ancillary system. The tritium produced in Pb–Li and ceramic breeder zones will be extracted by separate external ancillary systems. The R&D activities are being initiated in all critical areas related to DEMO relevant blanket concepts in order to test the TBM in ITER. In this paper, the design description, preliminary analysis, some of the related ancillary systems and R&D activities for LLCB TBM are presented.
The diagnostic neutral beam (DNB) line shall be used to diagnose the He ash content in the D–T phase of the ITER machine using the charge exchange recombination spectroscopy (CXRS). Implementation of ...a successful DNB at ITER requires several challenges related to the production, neutralization and transport of the neutral beam over path lengths of 20.665
m, to be overcome. The delivery is aided if the above effects are tested prior to onsite commissioning. As DNB is a procurement package for INDIA, an ITER approved Indian test facility, INTF, is under construction at Institute for Plasma Research (IPR), India and is envisaged to be operational in 2015. The timeline for this facility is synchronized with the RADI, ELISE (IPP, Garching), SPIDER (RFX, Padova) in a manner that best utilization of configurational inputs available from them are incorporated in the design. This paper describes the facility in detail and discusses the experiments planned to optimise the beam transmission and testing of the beam line components using various diagnostics.
Indian Test Facility (INTF) and its updates Bandyopadhyay, M; Chakraborty, A; Rotti, C ...
Journal of physics. Conference series,
04/2017, Letnik:
823, Številka:
1
Journal Article
Recenzirano
Odprti dostop
To characterize ITER Diagnostic Neutral Beam (DNB) system with full specification and to support IPR's negative ion beam based neutral beam injector (NBI) system development program, a R&D facility, ...named INTF is under commissioning phase. Implementation of a successful DNB at ITER requires several challenges need to be overcome. These issues are related to the negative ion production, its neutralization and corresponding neutral beam transport over the path lengths of ∼ 20.67 m to reach ITER plasma. DNB is a procurement package for INDIA, as an in-kind contribution to ITER. Since ITER is considered as a nuclear facility, minimum diagnostic systems, linked with safe operation of the machine are planned to be incorporated in it and so there is difficulty to characterize DNB after onsite commissioning. Therefore, the delivery of DNB to ITER will be benefited if DNB is operated and characterized prior to onsite commissioning. INTF has been envisaged to be operational with the large size ion source activities in the similar timeline, as with the SPIDER (RFX, Padova) facility. This paper describes some of the development updates of the facility.
The 100-kV negative-hydrogen-ion-source-based diagnostic neutral beam (NB) (DNB) injector, which forms a part of the Indian (IN) procurement package for ITER, targets a delivery of ~18-20 A of ...neutral hydrogen-atom beam current into the ITER torus for charge exchange resonance spectroscopy diagnostics. Considering stripping losses, a ~70-A negative ion current is required to be extracted from the ion source, which leads to a production of 60 A of accelerated ion beam. Subsequent process of neutralization, electrostatic ion separation, and transport to the duct leads to a large separation between the points of generation of the ion beam to the point of delivery of the NB into the torus (~23 m). This forms one of the most important constraints for the transport of NBs to ITER. The requirements are not only for a stringent control over ion optics, the transport to electrostatic separator, minimum loss of beam due to intercepting elements, low reionization loss, and focusing to control interception losses but also for adequate compensation of residual magnetic fields to overcome magnetic field induced deflections also form important design issues for a reasonable transmission efficiency. Due to multiparameter dependence, it becomes necessary to assess the different scenarios using numerical codes. In the present case, the assessment has been carried out for the DNB using the beam-transport codes PDP, BTR, and the MCGF codes which are developed by the Russian Federation. An optimized configuration of the beamline has been arrived at on the basis of these code-enabled studies. These parameters are the following: listing of the vertical and horizontal focal lengths as 20.6 m, a spacing between ground grid and neutralizer of 1 m, and positioning of residual-ion dump at a distance of 0.75 m from the neutralizer exit. Further, optimizing the gas feed to the source and neutralizer leads to a final transmission of ~35% of the extracted beam power to the torus. This paper shall present the methodology, the issues concerned, and the final configuration which forms the basis for the present engineering.
PDF
