Ultrasounds

How it works?

Depending on the environment (liquid, solid, gas), the phenomena created by ultrasounds are different, making it possible to meet the needs of a wide range of applications. The table below summarises, depending on the environment, the effect induced and some interesting nuclear applications.

Liquid

Effect: Cavitation

Surface decontamination (≈ 20 KHz)
Sonochemistry (≈ MHz)

Effect : Atomisation

Spraying fine droplets

Solid

Effect: Vibration

Ultrasound produces a vibratory excitation on the material with an amplitude of a few microns, resulting in a vibratory force of a few millimetres > to the Van der Waals force. The particles will be detached from the surface, allowing applications such as:

Unclogging filters and sieves
Removal of fine, slightly encrusted particles from metal surfaces

Ultrasonic vibration also reduces the coefficient of friction between particles, which also makes it possible to use ultrasound for:

Cutting materials (e.g. bitumen)

Gas

Effect: Acoustic wind

Ultrasonic technology produces an acoustic wind in front of the probe without any gas displacement. : The focusing of the acoustic waves produced by the US probe creates a pressure field a few centimetres away which causes the particles to move..

This acoustic wind phenomenon can be used for:

Surface dusting (e.g. ultrasound blower)
Defoaming

Examples of applications?

In Liquid:

Effect : Cavitation

Surface decontamination
Removing hot spots in pipes

Cavitation bubbles, which are created when they encounter a solid surface, implode on this surface, forming very violent microjets of liquid (100 m/s) that allow surface decontamination.

To obtain a good decontamination factor, it is important to choose:

The power in W/l
Ultrasonic frequency

Examples of feedback from equipment designed by SINAPTEC:

Setup of US submersible blocks in a decontamination tank for waste in the dismantling cell of Orano's R7 vitrification workshop at La Hague.

Decontamination of the refrigeration loop on R7 (Orano La Hague).

Removal of a hot spot on DN40 flat piping with 10 mSv/h on contact (EDF).

In solid:

Effect: Vibration

Removal of fine particle deposits from equipment (tanks, valves)
Dry decontamination
Filter cleaning (sonotrode on metal filter)

Ultrasound produces a vibratory excitation on the material with an amplitude of a few microns, resulting in a vibratory force of a few millimetres > to the Van der Waals force. The particles will be detached from the surface.

Examples of feedback from equipment designed by SINAPTEC: