Mechanical measurements in RFX-mod experiment

• Published in: Fusion engineering and design Vol. 85; no. 7; pp. 1279 - 1282
• Main Authors: Palma, M. Dalla, Ravarotto, D., Dal Bello, S., Fincato, M., Ghiraldelli, R., Marchiori, G., Taliercio, C., Zaccaria, P.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.12.2010; Elsevier
• Subjects: Applied sciences; Controled nuclear fusion plants; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Installations for energy generation and conversion: thermal and electrical energy; Magnetizing current; Mechanical measurements; Ohmic heating windings; Potentiometers; Real-time mechanical measurement system; Relative displacements; Strain gauges; Relative displacements; Strain gauges; Magnetizing current; Potentiometers; Ohmic heating windings; Mechanical measurements; Real-time mechanical measurement system; Real time; Stress strain; Nuclear fusion reactor; Sampling; Reliability; Magnetic field
• ISSN: 0920-3796; 1873-7196
• DOI: 10.1016/j.fusengdes.2010.03.026

The ongoing experimental campaigns of RFX-mod are performed setting operational parameters at the nominal or exceeding design values of the experiment. Compressive forces up to 11 MN are produced by high magnetizing currents that reach values up to 50 kA. These forces heavily load the mechanical structure of RFX-mod and their effects are measured and monitored in order to assess the expected structural response and machine reliability during operation. Mechanical strains and relative displacements are real time measured during each experimental pulse by 48 strain gauges located on 12 mechanical struts and 16 potentiometers positioned between the toroidal assembly and the support mechanical structure. The strains in the most stressed components are measured by means of 24 half bridge gauges preliminarily calibrated. Particular care has been given to sensor choices and installation in order to minimize signal noises induced by the electrical and magnetic fields. The residual noises have been further reduced by proper sampling frequency and averaging techniques. The strains measured on the struts are then post-processed to calculate the resultant forces and bending moments, while the displacement measurements give an estimate of the overall stiffness of the mechanical structure. The measured forces and displacements are shown per toroidal locations and as a function of the current intensity, so verifying the uniform sharing of forces among the different struts and the proper square law correlation with the magnetizing current intensity.