7. Conclusion

As part of a policy to optimize the burnup rate of nuclear fuel unloading, non-destructive measurement of the pressure and composition of fission gases in a fuel assembly would :

• build up a statistical database on the evolution of internal pressure in fuel rods, and thus better assess margins with respect to the corresponding safety criterion (using EDF's CYRANO3 simulation software);

• assist in the decision to reload an assembly;

• detect the faulty pencil in an assembly that has been identified as leaky but can be repaired;

• characterize the condition of assemblies prior to storage, and monitor their evolution over time.

The innovative acoustic system presented here meets all these needs.

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