The demand for advanced materials in constructing next generation nuclear reactors has intensified the need to explore additive manufacturing (AM) processes as an alternate means of fabricating components. In this study, Inconel 625 (IN625) and Inconel 718 (IN718) samples fabricated using Laser Powder Bed Fusion (L-PBF) were irradiated using fast neutrons. Samples investigated included as-printed and heat-treated at either 700, 900, or 1050 ℃ for 1 hour to understand the impact of heat treatment on any neutron irradiation hardening. Wrought IN625 and IN718 samples were also inspected for experimental control. All samples were irradiated for 7 weeks resulting in a total fluence 2.74x10

15 neutrons/cm

1. To quantify radiation damage, the Vickers microhardness was measured before and after fast neutron irradiation. Results show that the IN718 samples experienced less change (-2.5 to 3.24 %) in microhardness. On the other hand, IN625 samples underwent more (0.9 to 7.21%) change in microhardness post fast neutron irradiation.