|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Materials and Fuels for the Current and Advanced Nuclear Reactors VII
||Microstructural and Mechanical Integrity of Laser Weldment of Neutron Irradiated AISI 304 SS
||Keyou Mao, Paula D. Freyer, Frank A. Garner, Janelle P. Wharry
|On-Site Speaker (Planned)
The objective of this study is to characterize the integrity of low heat input pulsed laser weld repairs of neutron irradiated AISI 304 stainless steel (SS). During life extension of light water reactors, weld repairs of cracked internals are complicated by the irradiated, voided, helium-containing microstructure, which exacerbates cracking. In this work, we investigate the effectiveness of laser beam welding at preventing helium bubble coalescence and cracking at the weld boundary. We conduct a single-pass weld using 308 L filler wire on a 304 SS hex block section, which was irradiated in EBR-II to ~1-4 displacements per atom and contains ~1 appm helium and ~1% swelling. We use scanning electron microscopy and transmission electron microscopy to characterize the microstructures of the filler metal, heat affected zone, and irradiated base metal. Nanoindentation assesses mechanical properties across the irradiated weldment. The combination of microstructural and mechanical results helps reveal helium cracking mechanisms.
||Planned: Supplemental Proceedings volume