7. Conclusion

For use in nuclear laboratories (in air with a viscous liquid as coupler), with the latest generation of acoustic sensors dedicated to fission gas characterization, it was possible to determine composition with an uncertainty of around 1%, and pressure with an uncertainty of around 10% (for around 50 bar internal pressure and a gas mixture containing 20% Xe/Kr).

Improvements to these sensors enable us to reduce the lower pressure limit and the uncertainty of pressure measurement. It also enables us to measure pure helium up to a high Xe concentration on a fuel rod incorporating an underwater holding spring.

By optimizing signal processing and reducing the water layer, the reference sensor enables the internal pressure level of a fuel rod (irradiated or not) to be determined with acceptable accuracy.

This level of...