ITER Neutral Beam Test Facility

Last updated
View of the Neutral Beam Test Facility View of the Neutral Beam Test Facility building.jpg
View of the Neutral Beam Test Facility

The ITER Neutral Beam Test Facility is a part of the International Thermonuclear Experimental Reactor (ITER) in Padova, Veneto, Italy. [1] The facility will host the full-scale prototype of the reactor's neutral beam injector, MITICA (Megavolt ITer Injector & Concept Advancement), and a smaller prototype of its ion source, SPIDER (Source for the Production of Ions of Deuterium Extracted from a Radio frequency plasma). [2] SPIDER started its operation in June 2018. SPIDER will be used to optimize the ion beam source, to optimize the use of caesium vapor, and to verify the uniformity of the extracted ion beam also during long pulses.

Contents

ITER heating neutral beams

To deliver power to the fusion plasma in ITER, two heating neutral beam injectors will be installed. They are designed to provide the power of 17 MW each, through the 23 m beamlines, up to the four-meter diameter container: in order to deposit sufficient heating power in the plasma core instead of the plasma edges, the beam particle energy shall be about 1 MeV, thus increasing the neutral beam system complexity to an unprecedented level. This will be the main auxiliary heating system of the reactor. Due to its low conversion efficiency, the neutral beam injector first needs to start a precursor negative ion beam of 40 A, and then neutralizes it by passing it through a gas cell (with an efficiency < 60%), and then by a residual ion dump (the remaining 40—20% negative, 20% positive). The neutralized beam is then dumped on a calorimeter during conditioning phases, or coupled with the plasma. Further reionization losses or interception with the mechanical components reduce its current to 17 A. [3]

Purposes

Inside view of the neutral beam test facility; picture taken from the top of MITICA bioshield, during the maintenance of SPIDER (reassembly of SPIDER ongoing in the working area at the center of the picture) Inside view of NBTF.jpg
Inside view of the neutral beam test facility; picture taken from the top of MITICA bioshield, during the maintenance of SPIDER (reassembly of SPIDER ongoing in the working area at the center of the picture)

The role of the test facility includes research and development on the following topics:

Prototypes at the NBTF

Negative ion extraction with reduced number of beamlets, in early volume operation of SPIDER (May/June 2019) SPIDER during negative ion extraction.png
Negative ion extraction with reduced number of beamlets, in early volume operation of SPIDER (May/June 2019)

SPIDER is the first large experimental devices to start the operation at the test facility (May 2018). The components of MITICA are currently under procurement, with its first operation expected in late 2023.

SPIDER

The design parameters of SPIDER are the following:

During 2018, the plasma discharge by eight ion source RF drivers were optimised. In 2019 the operation with hydrogen negative ion beam begun: for the first year, SPIDER will operate with a reduced number of beamlets (80 instead of 1280) due to limitations in the vacuum system. In 2021, the first operation with caesium was performed.

Capabilities

The capabilities of SPIDER and MITICA are listed in the following table in comparison with the objectives of the ITER Heating Neutral Beam and with other existing devices based on RF-driven sources. The obtained results reported in table refers to the operation at low filling pressure of 0.3 Pa; a marked improvement of performances is found for higher operating pressures, but a low pressure is requried to minimise the heat loads due to stray particles, generated by interaction of the beam ions with the background gas along the multi-grid electrostatic accelerator of MITICA and ITER HNB sources.

ExperimentFirst operationBeam energy (achieved/ target)negative ion beam current (achieved/ target)negative ion beam current density (achieved/ target)Ion source typeAccelerator typeNeutraliser typeBeamline lengthNeutral beam equivalent currentTarget single beamlet divergence at 0.3 Pa (gaussian 1/e)Achieved single beamlet divergence at 0.3 Pa ±10% (gaussian 1/e)
BATMAN Upgrade [4] upgraded in 2018~60 kV ? (hydrogen)350 A/m2 [5] / 330 A/m2 (hydrogen)RF-driven caesiated surface-plasma sourceMulti-aperture electrostatic triode-~3 m--11 mrad (core divergence including ~75% beamlet current)
ELISE [6] Feb 2013~60 kV~27 A (hydrogen)~280 A/m2 [7] / 330 A/m2 (hydrogen)RF-driven caesiated surface-plasma sourceMulti-aperture electrostatic triode-~5 m---
SPIDERMay 201850 kV [8] / 110 kV~1 A [8] / 54 A (hydrogen)225 A/m2 [8] / 330 A/m2 (hydrogen)RF-driven caesiated surface-plasma sourceMulti-aperture electrostatic triode-~5 m-<7 mrad12 mrad [8]
MITICA2025 (expected)880 kV (hydrogen) / 1000 kV (deuterium)-/ 40 A (hydrogen)-/ 330 A/m2 (hydrogen)RF-driven caesiated surface-plasma sourceMulti-grid multi-aperture concept (7 electrodes)4 Gas cells~13 m16.7 A<7 mrad-
ITER HNBTBD880 kV (hydrogen) / 1000 kV (deuterium)40 A-/ 330 A/m2 (hydrogen)RF-driven caesiated surface-plasma sourceMulti-grid multi-aperture concept (7 electrodes)4 Gas cells~22.5 m16.7 A<7 mrad-

See also

Related Research Articles

<span class="mw-page-title-main">Nuclear fusion</span> Process of combining atomic nuclei

Nuclear fusion is a reaction in which two or more atomic nuclei, usually deuterium and tritium, combine to form one or more different atomic nuclei and subatomic particles. The difference in mass between the reactants and products is manifested as either the release or absorption of energy. This difference in mass arises due to the difference in nuclear binding energy between the atomic nuclei before and after the reaction. Nuclear fusion is the process that powers active or main-sequence stars and other high-magnitude stars, where large amounts of energy are released.

<span class="mw-page-title-main">Tokamak</span> Magnetic confinement device used to produce thermonuclear fusion power

A tokamak is a device which uses a powerful magnetic field generated by external magnets to confine plasma in the shape of an axially-symmetrical torus. The tokamak is one of several types of magnetic confinement devices being developed to produce controlled thermonuclear fusion power. The tokamak concept is currently one of the leading candidates for a practical fusion reactor.

<span class="mw-page-title-main">Fusor</span> An apparatus to create nuclear fusion

A fusor is a device that uses an electric field to heat ions to a temperature in which they undergo nuclear fusion. The machine induces a potential difference between two metal cages, inside a vacuum. Positive ions fall down this voltage drop, building up speed. If they collide in the center, they can fuse. This is one kind of an inertial electrostatic confinement device – a branch of fusion research.

<span class="mw-page-title-main">Fusion power</span> Electricity generation through nuclear fusion

Fusion power is a proposed form of power generation that would generate electricity by using heat from nuclear fusion reactions. In a fusion process, two lighter atomic nuclei combine to form a heavier nucleus, while releasing energy. Devices designed to harness this energy are known as fusion reactors. Research into fusion reactors began in the 1940s, but as of 2024, no device has reached net power, although net positive reactions have been achieved.

This timeline of nuclear fusion is an incomplete chronological summary of significant events in the study and use of nuclear fusion.

<span class="mw-page-title-main">Joint European Torus</span> Facility in Oxford, United Kingdom

The Joint European Torus (JET) was a magnetically confined plasma physics experiment, located at Culham Centre for Fusion Energy in Oxfordshire, UK. Based on a tokamak design, the fusion research facility was a joint European project with the main purpose of opening the way to future nuclear fusion grid energy. At the time of its design JET was larger than any comparable machine.

<span class="mw-page-title-main">ITER</span> International nuclear fusion research and engineering megaproject

ITER is an international nuclear fusion research and engineering megaproject aimed at creating energy through a fusion process similar to that of the Sun. Upon completion of construction of the main reactor and first plasma, planned for late 2025, it will be the world's largest magnetic confinement plasma physics experiment and the largest experimental tokamak nuclear fusion reactor. It is being built next to the Cadarache facility in southern France. ITER will be the largest of more than 100 fusion reactors built since the 1950s, with ten times the plasma volume of any other tokamak operating today.

<span class="mw-page-title-main">Inertial electrostatic confinement</span> Fusion power research concept

Inertial electrostatic confinement, or IEC, is a class of fusion power devices that use electric fields to confine the plasma rather than the more common approach using magnetic fields found in magnetic confinement fusion (MCF) designs. Most IEC devices directly accelerate their fuel to fusion conditions, thereby avoiding energy losses seen during the longer heating stages of MCF devices. In theory, this makes them more suitable for using alternative aneutronic fusion fuels, which offer a number of major practical benefits and makes IEC devices one of the more widely studied approaches to fusion.

<span class="mw-page-title-main">Neutron generator</span> Source of neutrons from linear particle accelerators

Neutron generators are neutron source devices which contain compact linear particle accelerators and that produce neutrons by fusing isotopes of hydrogen together. The fusion reactions take place in these devices by accelerating either deuterium, tritium, or a mixture of these two isotopes into a metal hydride target which also contains deuterium, tritium or a mixture of these isotopes. Fusion of deuterium atoms results in the formation of a helium-3 ion and a neutron with a kinetic energy of approximately 2.5 MeV. Fusion of a deuterium and a tritium atom results in the formation of a helium-4 ion and a neutron with a kinetic energy of approximately 14.1 MeV. Neutron generators have applications in medicine, security, and materials analysis.

<span class="mw-page-title-main">Gridded ion thruster</span> Space propulsion system

The gridded ion thruster is a common design for ion thrusters, a highly efficient low-thrust spacecraft propulsion method running on electrical power by using high-voltage grid electrodes to accelerate ions with electrostatic forces.

The Small Tight Aspect Ratio Tokamak, or START was a nuclear fusion experiment that used magnetic confinement to hold plasma. START was the first full-sized machine to use the spherical tokamak design, which aimed to greatly reduce the aspect ratio of the traditional tokamak design.

<span class="mw-page-title-main">Madison Symmetric Torus</span>

The Madison Symmetric Torus (MST) is a reversed field pinch (RFP) physics experiment with applications to both fusion energy research and astrophysical plasmas.

<span class="mw-page-title-main">KSTAR</span> Nuclear fusion research facility in South Korea

The KSTAR is a magnetic fusion device at the Korea Institute of Fusion Energy in Daejeon, South Korea. It is intended to study aspects of magnetic fusion energy that will be pertinent to the ITER fusion project as part of that country's contribution to the ITER effort. The project was approved in 1995, but construction was delayed by the East Asian financial crisis, which weakened the South Korean economy considerably; however, the project's construction phase was completed on September 14, 2007. The first plasma was achieved in June 2008.

Neutral-beam injection (NBI) is one method used to heat plasma inside a fusion device consisting in a beam of high-energy neutral particles that can enter the magnetic confinement field. When these neutral particles are ionized by collision with the plasma particles, they are kept in the plasma by the confining magnetic field and can transfer most of their energy by further collisions with the plasma. By tangential injection in the torus, neutral beams also provide momentum to the plasma and current drive, one essential feature for long pulses of burning plasmas. Neutral-beam injection is a flexible and reliable technique, which has been the main heating system on a large variety of fusion devices. To date, all NBI systems were based on positive precursor ion beams. In the 1990s there has been impressive progress in negative ion sources and accelerators with the construction of multi-megawatt negative-ion-based NBI systems at LHD (H0, 180 keV) and JT-60U (D0, 500 keV). The NBI designed for ITER is a substantial challenge (D0, 1 MeV, 40 A) and a prototype is being constructed to optimize its performance in view of the ITER future operations. Other ways to heat plasma for nuclear fusion include RF heating, electron cyclotron resonance heating (ECRH), ion cyclotron resonance heating (ICRH), and lower hybrid resonance heating (LH).

<span class="mw-page-title-main">ASDEX Upgrade</span>

ASDEX Upgrade is a divertor tokamak at the Max-Planck-Institut für Plasmaphysik, Garching that went into operation in 1991. At present, it is Germany's second largest fusion experiment after stellarator Wendelstein 7-X.

<span class="mw-page-title-main">Tokamak à configuration variable</span> Swiss research fusion reactor at the École Polytechnique Fédérale de Lausanne

The tokamak à configuration variable is an experimental tokamak located at the École Polytechnique Fédérale de Lausanne (EPFL) Swiss Plasma Center (SPC) in Lausanne, Switzerland. As the largest experimental facility of the Swiss Plasma Center, the TCV tokamak explores the physics of magnetic confinement fusion. It distinguishes itself from other tokamaks with its specialized plasma shaping capability, which can produce diverse plasma shapes without requiring hardware modifications.

The polywell is a proposed design for a fusion reactor using an electric and magnetic field to heat ions to fusion conditions.

<span class="mw-page-title-main">Plasma-facing material</span>

In nuclear fusion power research, the plasma-facing material (PFM) is any material used to construct the plasma-facing components (PFC), those components exposed to the plasma within which nuclear fusion occurs, and particularly the material used for the lining the first wall or divertor region of the reactor vessel.

<span class="mw-page-title-main">Hybrid Illinois Device for Research and Applications</span> Toroidal magnetic fusion device

The Hybrid Illinois Device for Research and Applications (HIDRA) is a medium-sized toroidal magnetic fusion device housed in the Nuclear Radiation Laboratory and operated by the Center for Plasma-Material Interactions (CPMI) within the Department of Nuclear, Plasma and Radiological Engineering at the University of Illinois at Urbana–Champaign, United States. HIDRA had its first plasma at the end of April 2016 and started experimental campaigns by December of that year. HIDRA is the former WEGA classical stellarator that was operated at the Max Planck Institute for Plasma Physics in Greifswald Germany from 2001 to 2013.

Colliding beam fusion (CBF), or colliding beam fusion reactor (CBFR), is a class of fusion power concepts that are based on two or more intersecting beams of fusion fuel ions that are independently accelerated to fusion energies using a variety of particle accelerator designs or other means. One of the beams may be replaced by a static target, in which case the approach is termed accelerator based fusion or beam-target fusion, but the physics is the same as colliding beams.

References

  1. "ITER Neutral Beam Test Facility: Construction is progressing fast in Padova". EUROfusion. 15 July 2013. Archived from the original on 2016-01-27. Retrieved 2023-11-05.
  2. V. Toigo, D. Boilson, T. Bonicelli, R. Piovan, M. Hanada, et al. 2015 Nucl. Fusion 55:8 083025
  3. LR Grisham, P Agostinetti, G Barrera, P Blatchford, D Boilson, J Chareyre, et al., Recent improvements to the ITER neutral beam system design, Fusion Engineering and Design 87 (11), 1805-1815
  4. Fantz, U.; Bonomo, F.; Fröschle, M.; Heinemann, B.; Hurlbatt, A.; Kraus, W.; Schiesko, L.; Nocentini, R.; Riedl, R.; Wimmer, C. (2019). "Advanced NBI beam characterization capabilities at the recently improved test facility BATMAN Upgrade". Fusion Engineering and Design. 146: 212–215. Bibcode:2019FusED.146..212F. doi:10.1016/j.fusengdes.2018.12.020. hdl:21.11116/0000-0004-8043-F.
  5. Heinemann, B.; Fantz, U.; Kraus, W.; Schiesko, L.; Wimmer, C.; Wünderlich, D.; Bonomo, F.; Fröschle, M.; Nocentini, R.; Riedl, R. (2017). "Towards large and powerful radio frequency driven negative ion sources for fusion". New Journal of Physics. 19 (1): 015001. Bibcode:2017NJPh...19a5001H. doi:10.1088/1367-2630/aa520c.
  6. World's largest test facility for negative ion sources opens to develop heating for ITER – December 2012 Archived 2019-08-02 at the Wayback Machine . Retrieved on 2019-08-02.
  7. Fantz, U.; Briefi, S.; Heiler, A.; Wimmer, C.; Wünderlich, D. (2021). "Negative Hydrogen Ion Sources for Fusion: From Plasma Generation to Beam Properties". Frontiers in Physics. 9: 473. Bibcode:2021FrP.....9..473F. doi: 10.3389/fphy.2021.709651 .
  8. 1 2 3 4 Sartori, E.; Agostini, M.; Barbisan, M.; Bigi, M.; Boldrin, M.; Brombin, M.; Casagrande, R.; Dal Bello, S.; Dan, M.; Duteil, B.P.; Fadone, M.; Grando, L.; Maistrello, A.; Pavei, M.; Pimazzoni, A. (2022). "First operations with caesium of the negative ion source SPIDER". Nuclear Fusion. 62 (8): 086022. Bibcode:2022NucFu..62h6022S. doi:10.1088/1741-4326/ac715e. ISSN   0029-5515.

45°23′26″N11°55′40″E / 45.39056°N 11.92778°E / 45.39056; 11.92778