.. .. Distance,

I. .. Results,

.. .. Conclusion,

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, components of the reactor building, (b) specied components of the High Flux Reactor, The High Flux Reactor structure, vol.13

, General structure of the RHF fuel element [13], (b) zoom over fuel plates

, The fuel plate dimensions

, Experimental ultrasonic signal displaying two echo series, (I) reected echo series on the silica support, (II) reected echo series on the plate

, Inter-plate distance measurements

. .. , Multilayered composition of the transducer, p.48

, Modeled ultrasonic signal of a 90 MHz central frequency transducer displaying two echo series, (a) reected echo series on the silica/water interface, (b) reected echo series on the water/plate interface

, 5 (a) Modeled received ultrasonic signal with an adhesive layer thickness of 13 µm; (b) Reected series on the WP interface, vol.2

, Modeled received ultrasonic signal with an adhesive layer thickness of 10 µm; (b) Reected series on the WP interface

.. .. Mhz,

, Ultrasonic eld generated in silica and water by a 1 mm diameter plane surface at 90 MHz. (a) displayed in the silica of 0.4 mm, (b) displayed until 20 mm

, plane surface at 90 MHz. (a) displayed until 2 mm, (b) displayed until 20 mm

. .. Assembled-ultrasonic-device,

. .. , The chassis including electronic instruments, vol.54

, Signal received through a cable of 8 m: (a) before (b) after ltering

, Electric (black) and acoustic (red) echoes considering a cable of 8 m

, 15 (a) Reected signal on the cable (b) reected signal through the transducer, vol.2

, Two signals: (red) signal received after the transducer excitation and ltered; (black) signal received after the transducer excitation without ltering

. Ulm-tilt, ) rotational motor, (3) mounting support, (4) dual translation plates, Measurement bench design, issue.1

, 19 (a) NI?9411 card for counting and position indicating; (b) Linear cable sensor, vol.2

. .. , , p.60

, Ultrasonic wave propagation through the mediums and the corresponding acquired signal including two echo series

. .. , 2 (a) Acquired ultrasonic signal before bandpass ltering; (b) Acquired ultrasonic signal after bandpass ltering

, An ultrasonic signal with three reected echo series from the facing sample surface

, Acquired ultrasonic signal with distinguished reected series; (b) Acquired ultrasonic signal with overlapped reected series

, 5 (a) First case ultrasonic signal after reference signal subtraction; (b) Second case ultrasonic signal after reference signal subtraction, vol.3, p.67

, 6 (a) Supperposition of the acquired ultrasonic signal and the reference signal; (b) One time period of both the signals in points, p.67

, Time of ight measurement results

. .. , An ultrasonic signal superposed with its oversampled signal, (a) ultrasonic echo, (b) a zoom over 2 ns

, First case after reference signal subtraction; (a) without oversampling, (b) with oversampling

, Second case after reference signal subtraction; (a) without oversampling, (b) with oversampling

, Superposed reference and experimental signals: delayed reference signal in red and subtracted signal in black, (a) visualization of complete signals (b) a zoom on the WP series, p.70

. .. , Nuclear irradiator installation scheme, p.95

, Ultrasonic devices and single elements in the irradiation cell, p.99

, Acquisition and monitoring system placed outside the irradiation cell

, Ultrasonic transducers spectra all over the irradiation experiment days

, Relative frequency, amplitude and bandwidth variation of reference transducers and cables: rst line graphs are at laboratory and second line graphs are outside irradiation cell for reference transducers while cables are irradiated

, Relative frequency, amplitude and bandwidth variation of the transducers

, Time signal comparison between the functioning case (red) and the malfunctioning case (blue)

, multilayered structure group microscopic images before irradiation

, Acoustic signature process

, 1 (a) Experimental signal energy measurements; (b) Selected signals for distance measurements

, 2 (a) Previous and new signal processing comparison; (b)New signal processing distance measurements

, New ultrasonic device in the RHF experiment [13] (a) inserted in the fuel element; (b) introduced between fuel plates, p.122

, Blue squares correspond to the simulated values and red points to the experimental data; (a) transducer 1; (b) transducer 2, p.123

. .. , Both transducers' frequency spectra of the selected wave packet positioned between the two vertical lines of gures (a) and (b), 5 (a) and (b) Both transducers' received ultrasonic signals in the medium; (c) and (d), p.127

, Energy measurements performed between plates 13 and 14. Red points correspond to transducer 1 energy measurements and blue squares for transducer 2

. .. Device-positionning-measurements,

, Experimental signals after oversampled reference signal subtraction; (a) transducer 1 (b) transducer 2

. .. Inter-plate-distance-measurements, 130 position measurements; (b) Inter-plate distance measurements according to the vertical position measurements