The scientific and technological activities of Consorzio RFX in Fusion research allowed to develop several components and systems that found (or may find in the near future) applications in industry. Moreover, the analysis and design methods developed for RFX were successfully applied to solve a variety of problems in industrial plants and production lines.
A few examples are given in the following.
1. Spin-offs related to turbulence studies.
The diagnostics developed for the study of edge physics in RFX and related tools of turbulence analysis have been applied to the study of turbulence developed in a prototype Magneto-Plasma Dynamic thruster for satellite applications, operating at Centro Spazio, Pisa in Italy. Results are expected to contribute to a better understanding of the processes underlying the thruster performance.
1.3 Plasma Processing
Diagnostics, methods and interpretation models have been applied to measure basic and fluctuating properties of plasmas produced in a magnetronsputtering device for deposition of thin films. The results are expected to improve reproducibility of deposited films through a better control of plasma parameters. The results obtained so far contribute to a better understanding of the phenomena underlying the loss mechanisms and give insights on methods to improve the device efficiency.
2. Spin-offs related to basic plasma physics
2.1 SF6 Switchgears
Modelling of current interruption in a Sulphur Hexafluoride high-voltage Switchgear has been developed for investigation of post arc phenomenology during current interruption. The model is based on the competition between sheath expansion and contacts velocity. To fulfill thermal stress demand and/or low emission of secondary electrons, special materials used in fusion research have been considered. Combination of models and advanced materials and component design are expected to contribute to improve the efficiency of the current interruption process.
3. Spin-offs related to developments in instrumentation
3.1 Plasma cutting torches
A collaboration has been established with an industrial partner in the field of plasma arc cutting. The plasma jet used in the cutting process can deliver an extremely high power density (of the order of 1000 MW/m2 in steady state operation) and therefore can be exploited for higher quality and improved productivity metal fabrication. A diagnostic equipment for the electric imaging of the plasma arc has been developed and used for the characterization and optimization of the plasma arc torches; its development is largely based on techniques used in fusion research.
3.2 Optical link for analog signal transmission
In the power supply systems for fusion plants, the transmission of analog signals is a crucial issue due to the high insulation and noise immunity requirements.
A new optical link was developed at this purpose, which guarantees a bandwidth of 25 kHz, low offset values without drifts with time and temperature, that are typical of other links previously utilized. Another important feature is that this link allows the transmission of two signals in the same fiber optic.
The performance/price ratio of this product is very good with respect to others available in the market, thus it may be very interesting not only for measurements in high and medium voltage plants, but also for a large variety of industrial applications.
3.3 Photonics amplifier
A custom photonics amplifier has been developed in collaboration with an industrial company to be used with avalanche photodiodes in the Thomson Scattering diagnostic for the RFX experiment.
This transimpedance amplifier combines good performance (low noise, wide bandwidth) with a low price and a well engineered compact design, characteristics that make it generally suitable for amplification of low current signal optical detectors, also in noisy environment.
The amplifier has already been used as a photodiode amplifier in another photografic application for color measurements.
4. Spin-offs related to control technologies
4.1 Process Automation
RFX is controlled and monitored by an industrial-type control system based on a network of programmable controllers (Siemens SIMATIC S5 family) and personal computers running a commercial package for system supervision (USDATA - FactoryLink).
The system was developed by the RFX team in 1988-1991, in collaboration with an industrial company.
The technologies in the field of process automation, approached by the company during the implementation of the RFX system, have been extensively re-used by the company in the following years.
4.2 Full-digital control board for switching converters
A new digital control board for IGBT H bridge switching converters has been developed in collaboration with an industrial company, which produces systems for static energy conversion and automation. The converters are characterised by maximum output voltage and current of 650 V and 300 A, respectively, using IGBTs rated for 1200V/300A. The switching frequency is 10 kHz.
The board, although developed for a specific application in the field of nuclear research, is characterised by peculiar features, which makes it suitable also for industrial applications: it is integrated and compact (it contains all the elements needed for the control), it fulfils stringent specifications in terms of dynamic response and linearity and, thanks to the use of a DSP and of FPGAs which can be easily reprogrammed, it guarantees a high degree of flexibility.
4.3 High Throughput Ultra Rapid Valves for Gas Handling
Ultra rapid piezoelectric valves have been developed to handle gas injection in a pulsed mode with a capability of 50 times the throughput in steady state operation. A good reliability has been obtained over a long period of time and in the presence of high magnetic fields. These valves may find applications in industrial processes requiring fast pressure control.
5. Spin-offs related to robotics
5.1 Image recognition system
An image recognition system to be integrated in the control of the RFX remote handling system has been developed. The system is designed to recognize the location of the object to be handled with respect to the manipulator end effector and to close the motion control loop with the corrected values of the joint coordinates. It is particularly suitable for hostile environments with poor illumination, which are relevant also for space applications.
5.2 Robotics under vacuum
A mobile tracked vehicle has been developed for inspection under Ultra High Vacuum conditions. An extensive test program on its components (in particular, micro DC motoreducers and CCD color cameras with motorized zoom and focus) has been carried out to verify the performances and reliability under those conditions.
6. Spin-offs related to power supply studies
6.1 Bypass switch for protection of series compensation capacitor
The protection of power supplies in RFX required careful analysis of faults and relative protection systems; in particular operation of fast closing switches, also based on solid stated devices, was studied at this purpose. The experience gained was utilized in designing a new thyristor bypass switch for protection of a series compensation capacitor, to sustain the voltage in a weak line feeding an arc furnace plant.
Series capacitors have traditionally being protected against overvoltages due to system faults, by complex combination of spark-gaps, non linear resistors and mechanical bypass switches. The innovative solution for protection, is based on high-power light-fired thyristors with series inductor and resistor for current limitation at the switch closing. This bypass switch has been built and installed in an industrial plant and is now under commissioning.
6.2 A new SVC for power transmission improvement of lines in railway applications.
The voltage control in large experiments, like ITER, with Static Var Compensator (SVC) has been studied and analysed in the past, and the experience and computational tools developed at this purpose can be usefully employed for similar studies in other fields.
This spin-off was realized for a system study in the electric traction field, aimed at reducing the harmonic generation of a SVC, so as to avoid EMI interferences with the communication network. The SVC, designed to improve the voltage control of the lines supplying the rail vehicles, was based on a Thyristor Controlled Reactor (TCR), with a capacitor bank in parallel. The system study performed allowed to derive the spectra of the harmonics generated by two rail systems and led to the design of a special filter to lower the harmonics under the desired level.