This work was carried out as part of a research internship at the French Alternative Energies and Atomic Energy Commission (CEA) in the SERMA/LPEC department, focusing on neutronics and reactor physics. It marks the culmination of my master’s studies and represents the final step in a long academic journey, during which I have had the opportunity to deepen my knowledge and contribute to ongoing research in a stimulating and high-level scientific environment. Nuclear Thermal Propulsion (NTP) systems are incredibly interesting for future space explorations, such as crew-operated Mars missions. Compared to conventional chemical propulsion systems, NTP offers several key advantages: a higher specific impulse, which results in greater efficiency and thrust, shorter travel times for the same distance.