Properties of Irradiated Additively Manufactured 316L Steel for In-Core Applications – Mechanical and Microstructural Analyses

Abstract This paper focuses on separate aspects of the utilization of additive manufacturing (AM) for the in-core applications in the nuclear power industry. This study investigates the application of the laser direct energy deposition method (L-DED) to produce in-reactor metallic components within LWR nuclear reactors. 316L stainless steel with heat treatment was chosen as the material of interest for experimental evaluation of the material properties after the neutron irradiation. Samples for the tensile test at 300 °C and microstructural analysis (LOM, EBSD, SEM) were irradiated inside a drop-in capsule in the LVR-15 research reactor at Research Center Rez. Subsequently, the postirradiation examination (PIE) results are compared to those of non-irradiated counterparts to analyze the impact of in-reactor conditions. Furthermore, the non-irradiated samples, both conventional and AM, were tested at both the Research Center Rez and COMTES FHT a.s, to obtain independent results and validate the methodologies. To design the irradiation campaign, the calculation of residual activity after the irradiation period is performed using a SCALE module ORIGEN to inform future handling procedures and scheduling of post-irradiation examinations. The calculation of expected displacement per atom (dpa) is also included for direct comparison with results available in the literature.