TechnoFusión

The TechnoFusión project, currently in a preparatory study phase, involves the construction of a Singular Scientific-Technical Facility (National Centre for Fusion Technologies - TechnoFusión) in the Region of Madrid, Spain, creating the required infrastructure for the development of the technologies required for future commercial fusion reactors, and assuring participation by Spanish research groups and companies.

The Spanish scientific community already possesses a critical amount of expertise on the science and technology that is needed for the success of this ambitious project, as is evident from the results obtained by Spanish researchers in the fusion field over the past few decades. TechnoFusión intends to take advantage of the existing expertise of university research groups, public research organisations (Organismo Público de Investigación, OPI) and private companies, by focussing on priority areas for the development, testing and analysis of materials that are needed for the construction of a commercial thermonuclear fusion reactor or complex remote handing systems.

The behaviour of components under the extreme conditions of a reactor is largely unknown, and this is precisely what TechoFusión pretends to explore. For this purpose, facilities are required for the manufacture, testing and analysis of critical materials, as well as facilities for the development and exploitation of numerical codes for the simulation of the behaviour of materials under extreme conditions.

In summary, TechnoFusión will focus on the creation of infrastructures for the following research areas: 1) material production and processing, 2) material irradiation, 3) plasma-wall interaction (thermal loads and the mechanism of atomic damage), 4) liquid metal technology, 5) material characterization techniques, 6) remote handling and 7) computer simulation.

The Singular Scientific-Technical Facility TechnoFusión will thus consist of a complex of seven large experimentation areas, many of which are unique in the world, with the following main technical objectives:

Material Production and Processing

It is not yet decided what materials will be used to construct future fusion reactors, partly because it has not yet been possible to reproduce the extreme conditions to which such materials will be subjected. Therefore, it is of utmost importance to dispose of installations capable of manufacturing new materials on a semi-industrial scale and fabricating prototypes. Top priority materials include metals such as reinforced low activation ODS type steels (Oxide Dispersion Strengthened steels) and tungsten alloys. To manufacture such materials, equipment is required that currently is scarce or inexistent in Spain, such as a Vacuum Induction Furnace (VIM), a Hot Isostatic Pressing Furnace (HIP), a Furnace for Sintering assisted by a Pulsed Plasma Current (SPS), or a Vacuum Plasma Projection System (VPS).

Material Irradiation

Of course, exact reactor conditions are only reproduced inside an actual reactor. Even so, it is possible to simulate the effects of neutrons and gamma radiation on materials by irradiating with ions and electrons. The effect of neutron radiation will be simulated by combining three ion accelerators: one light ion accelerator of the tandem type for irradiating with He, with an energy of 6 MV, one light ion accelerator of the tandem type for irradiating with H (or D), with an energy of 5-6 MV, and a heavy ion accelerator of the cyclotron type, with k = 110, to implant heavy ions (Fe, W, Si, C) or high energy protons. In addition, a high field magnet (5-10 T) will be used to study the simultaneous effect of irradiation and magnetic fields on materials. The effect of ionizing gamma radiation will be simulated by an electron accelerator of the Rhodotron type with a fixed energy of 10 MeV, which will be shared with other areas of the Centre.

Plasma Wall Interaction

Inside a future fusion reactor, some materials will not only be subjected to radiation, but also to enormous heat loads due to their direct contact with the plasma. In view of this, not only must stationary conditions of high density, low temperature and high power be reproduced, but also violent transient events (known as ELMs in plasma physics literature). Therefore, two plasma generation devices are planned: one is a linear plasma device, meant to reproduce the cited stationary conditions, and the other is a QSPA (Quasi-Stationary Plasma Accelerator) to simulate the transients. Both devices will be able to work with H, D, He and Ar.

Liquid Metal Technology

Various components of ITER and IFMIF, and eventually future fusion reactors, will be based on the use of liquid metals, so that the associated technology is increasingly relevant. Much is still to be learned about their application as refrigerants, tritium generators, or neutron reproducers or moderators under extreme conditions. The experimental area will dispose of various liquid lithium loops, connected to the electron accelerator. The main goals are the study of the free surface of liquid metals when subjected to internal energy deposition, and the compatibility of structural materials with the liquid metal in the presence of radiation. In addition, it will be possible to study the influence of magnetic fields on the cited phenomena and to develop methods for the purification of the liquid metal, lithium enrichment, tritium extraction, and safety protocols for handling liquid metal.

Characterization Techniques

The implementation of a wide range of techniques for the detailed characterisation of commercial or locally developed materials is proposed, applied before, during, and after their exposure to radiation or heat loads. The characterisation techniques include mechanical techniques (electromechanical devices, miniature mechanical testing devices, thermal fluency testing devices, nano-indenting techniques, etc.), compositional techniques (Secondary Ions Mass Spectrometry (SIMS) and Atomic Probe Tomography (APT)), structural and microstructural techniques (High Resolution Transmission Electron Microscopy (HRTEM) and X-Ray Diffraction (XRD)), and material processing techniques (Focused Ion Beam Systems coupled to a Scanning Electron Microscope (FIB/SEM)). Various systems will be used to characterise physical properties (electrical, dielectric, optical, etc.). TechnoFusión aspires to become the national materials characterisation laboratory of reference, in view of the fact that some of the cited techniques, such as SIMS or APT, are not readily available in Spain.

Remote Handling Techniques

The conditions inside a fusion reactor are incompatible with the manual repair or replacement of parts, so that remote handling is indispensable. New robotic techniques need to be developed that are compatible with the hostile conditions, and existing techniques need to be certified for application at installations such as ITER or IFMIF. The size of the components that will be manipulated and the complications associated with their spatial location will require developing new remote handling techniques. Prototypes will be tested in an installation that is connected to the electron accelerator in order to simulate working conditions with gamma radiation, similar to those experienced during maintenance operations inside a reactor. Some prototypes considered for demonstrating remote handling capabilities are: the diagnostic Port Plugs (PP) and the Test Blanket Modules (TBM) for ITER, or the irradiation modules of IFMIF.

Computer Simulation

In order to study conditions that cannot be reached in experiment and to accelerate the development of novel systems for a future commercial fusion power plant, TechnoFusión will stimulate an ambitious programme of computer simulations, combining the existing experience in the fusion field with resources from the National Supercomputation Network. Its goals include the implementation of the global simulation of a commercial fusion reactor, the interpretation of results, the validation of numerical tools, and the development of new tools. Another indispensable goal is the creation of a data acquisition system and the visualisation of results.