In-service inspection of sodium fast reactors requires the development of non-destructive techniques adapted to the hot and opaque sodium environment and the complex accessibility of the reactor pressure vessel. As the French Atomic Energy Commission is leading the development of the Advanced Sodium Test Reactor for Industrial Demonstration (ASTRID) [1], ultrasound inspection approaches are currently investigated to deal with this complex task. Tight collaboration with the CIVA software team has established CIVA as the primary design tool to simulate the possible inspection methods and predict their performance. The technical studies presented in this paper have been implemented during the past few years and demonstrate the different inspection methods that were developed.