Research Progress on Irradiation Damage in High-Performance Nickel-Based Alloys for Advanced Reactors

Gen-IV nuclear systems demand structural materials with superior high-temperature mechanical integrity, corrosion resistance, and irradiation tolerance. Nickel-based alloys, owing to their excellent high-temperature properties, chemical stability, and irradiation resistance, have become leading candidate materials for key components in advanced reactors such as molten salt reactors and very-high-temperature gas-cooled reactors. This review comprehensively surveys typical reactor-grade nickel-based alloys—Hastelloy N/GH3535, Inconel 718, and Inconel 617—covering their in-service behavior, key properties, processing–microstructure relationships, and irradiation damage research. Special attention is given to irradiation-induced microstructural evolution, including point defect generation and migration during cascades, formation of dislocation loops and voids, helium bubble nucleation and growth, precipitation, and phase transformations, as well as their links to macroscopic property degradation (hardening, embrittlement, swelling, and creep). Recent advances in ion-irradiation experiments, microstructural characterization, nanomechanical testing, and computational methods (first-principles and molecular dynamics) are critically discussed. It is shown that irradiation resistance can be significantly enhanced through compositional optimization, grain-boundary and dislocation engineering, oxide-dispersion strengthening, and the design of heterogeneous interfaces. Finally, future research directions are proposed, emphasizing advanced characterization, multiscale modeling, and data-driven approaches for accelerating the development of next-generation irradiation-resistant nickel-based alloys.