Corrosion Testing Needs and Considerations for Additively Manufactured Materials in Nuclear Reactors

Abstract

The Advanced Materials and Manufacturing Technologies (AMMT) program within the Department of Energy, Office of Nuclear Energy (DOE-NE) has developed its current recommendation for its corrosion testing strategy to deploy additively manufactured (AM) materials in advanced nuclear reactors. Additive manufacturing technologies have developed rapidly in recent years, creating new opportunities and challenges for the nuclear industry. To adopt AM technologies, the corrosion performance of AM materials needs to be adequately evaluated.This document is divided into seven chapters designed to support the proposed corrosion research strategy. The strategy focuses on the testing of AM 316H stainless steel (SS) to align with the broader AMMT program. An overview of localized and uniform corrosion mechanisms and their synergy with other degradation modes is provided. Specifically, the corrosion resistance of 316H is largely provided by the presence of an intact chromium oxide film on the surface, and loss or damage of this film is generally responsible for corrosion degradation.Engineering concerns for corrosion behavior are discussed, including component failure mechanisms and corrosion codes and standards. While the standards are extensive, certain material testing standards do not exist that would be relevant for the AMMT program. Reactor-specific corrosion concerns for molten salt reactors, liquid metal-cooled reactors, and high-temperature gas reactors will guide corrosion testing. Key factors likely to influence corrosion properties of AM materials (especially 316H) include build porosity, the presence of unusual phases, residual stress, microsegregation within the cellular substructure, and surface roughness. Post-build treatments and process variability need to be assessed with multiple specimens that are microstructurally quantified to develop structureproperty-performance relationships with uncertainty quantification. Sufficient facilities exist, at least for initial program efforts focusing on characterization of unirradiated material in laboratory settings, across Argonne National Laboratory