The nuclear industry is facing a very concrete challenge: many nuclear power plants are expected to operate significantly longer than originally planned, while spare parts, qualified supply chains, and complete technical documentation are becoming increasingly difficult to obtain. At the same time, any technical modification, even to auxiliary and balance of plant systems, is subject to the highest requirements for safety, traceability, and qualification. In this context, Additive Manufacturing (AM) is gaining attention, not as an experimental technology, but as a potential means to secure spare part availability, introduce more flexible maintenance cycles, and implement technical improvements within a strictly regulated framework.
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Why AM Is Gaining Relevance in the Nuclear Sector Now
One key driver is the reality of aging nuclear assets. Large parts of the global nuclear fleet have reached an advanced operational age, turning maintenance into an ongoing strategic task. In France, for example, 39 out of 58 reactors reached 40 years of operation in 2025[1]. As a result, component availability –including documentation, tooling, and stable supply chains – has come sharply into focus. Bottlenecks do not arise only in reactor‑adjacent components; auxiliary and peripheral systems also strongly influence maintenance windows, outages, and the economic operation of plants.
AM addresses these challenges primarily through its digital process chain. Components can be reproduced based on available data and can also be reverse engineered via scanning, which is a particular advantage when dealing with obsolete parts. At the same time, AM opens up new degrees of design freedom: functional integration, internal channels, or flow‑optimized geometries can be realized where conventional manufacturing reaches its limits. In addition, rapid iteration cycles enable significantly shorter development and optimization phases. At the same time, AM also enables a shift to “next-level” materials, as the cost impact of material changes is significantly lower than with conventional manufacturing methods.
Obsolescence & Availability: AM as a Building Block for More Flexible Maintenance Cycles
Components wear out, original manufacturers disappear, and tooling or complete technical documentation is often no longer available, while lead times are becoming increasingly critical. This particularly affects auxiliary and peripheral systems that, while not directly safety‑critical, have a major impact on plant availability and lifecycle performance. These include so‑called obsolescence parts: components that are still required but can no longer be procured through regular channels, such as functional parts in pumps, valves, or auxiliary turbine systems, as well as specific housings or brackets. While these are predominantly metal parts, same tendency is seen also in polymer components, e.g. Those related to electrical control systems & switches.
Additive Manufacturing creates new options in this context. Based on existing data or targeted re‑engineering, such components can be reproduced and simultaneously adapted in terms of design, for example to improve cooling performance, increase mechanical robustness, or extend service life. AM thus becomes more than a substitute for conventional manufacturing; it evolves into a tool for adapting existing components to today’s operational requirements.
A practical industrial example is provided by energy company Equinor, which has been using AM systematically for several years to address obsolescence issues and risks in spare part supply. Additively manufactured components are used to avoid long lead times, produce spare parts on demand, and increasingly replace physical inventories with digital stock data. In one application, even seemingly minor components – such as polymer screws – were replaced through additive manufacturing, resulting in significant cost savings.[2]
This approach is based on the combination of 3D scanning, digital modeling, and additive manufacturing, enabling both metallic and polymer components to be reconstructed and reproduced. Especially for older plants with limited to spare parts, this eliminates a central maintenance challenge. Additive Manufacturing thus evolves from a pure production method into an integral part of digital maintenance and spare part strategies, particularly for remote or hard‑to‑access sites.
This example also illustrates why auxiliary systems often serve as an entry point for additive applications. They are typically more manageable from a regulatory perspective, while at the same time being highly relevant for plant operation. It also becomes clear how AM can support a more flexible maintenance and repair cycle: instead of relying on rare spare parts and complex, fragile supply chains, the ability to produce qualified components on demand comes closer within reach.
Safety‑Relevant Applications & Performance: When AM Not Only Replaces, but Improves
Beyond ensuring spare part availability, Additive Manufacturing offers another key potential in the nuclear sector: the targeted improvement of safety‑relevant functions. Unlike conventional processes such as machining or casting, additively manufactured components are built directly from metal or polymer powders. Complex geometries can be realized without tools or molds, opening new design freedom and allowing components to be rethought from the ground up.
A well‑known risk in nuclear fuel assembly cooling is the so‑called “leak problem,” where even very small particles in the coolant circuit can, over time, lead to progressive wear and, in extreme cases, damage to fuel rods. Leakers occur when tiny debris in the coolant loop wears through a fuel rod, exposing uranium pellets, where even a single 5 mm strand of wire can be sufficient to cause such a failure. While not a frequent issue, mitigating this risk is critical. Traditionally, more effective filtration came with the trade‑off of higher pressure drops, reducing overall plant efficiency. [3]
Geometrically optimized, additively manufactured components address this challenge directly: adapted flow guidance, integrated filter functions, or functional part design can reduce risks and enhance operational safety. A well‑known example is the Stronghold AM filter for boiling water reactors developed by Westinghouse. By leveraging AM to create complex, tortuous internal flow channels, it enables effective filtration of 5 mm debris while maintaining comparable pressure levels to less efficient conventional designs, demonstrating how AM can reconcile safety and performance requirements.
In various reactor types, targeted geometric adaptations have led to measurable improvement, for example, more effective removal of foreign particles or performance increases without additional pressure loss. What matters most is not the individual component, but the underlying principle: design freedom and functional integration enable new performance levels, provided that qualification and inspectability are consistently considered from the outset.
AM also opens new opportunities for complex, pressure‑bearing components. Additively manufactured pressurized components with flow‑optimized channels, efficient heat transfer and varying geometries demonstrate how performance is increased while still meeting high mechanical requirements. Such applications combine the advantages of additive manufacturing with the realities of nuclear qualification requirements and provide a robust perspective for the industrialization of qualified AM solutions. As the nuclear industry operates strictly within defined standards and regulatory frameworks, harmonized guidelines are essential to enable the adoption of such components. One key development in this context is the forthcoming EN 13445‑14 standard, which will provide a relevant framework for additively manufactured pressure vessel components and support further industrialization.
Qualification: The Essential Foundation for AM in the Nuclear Sector
Precisely because Additive Manufacturing increasingly contributes to availability, maintainability, and performance in the nuclear sector, qualification inevitably moves to the center of attention. In nuclear engineering, safety is not ensured by functional performance alone, but by transparent and verifiable evidence. Materials, manufacturing processes, inspection methods, and documentation must work together consistently and be traceable across the entire lifecycle. This is particularly true for additive processes, as component properties depend strongly on process stability – such as parameter sets, materials used, the build process itself, and post‑processing steps.
Qualification should not be seen as an obstacle, but as a necessary prerequisite for using the potential of additive manufacturing in the nuclear environment. In practice, this is often done step by step: initial applications focus on components that are regulatorily more manageable or located outside safety‑critical core systems. With growing experience, reliable data, and clearly defined process windows, the scope of application can be gradually expanded. As international standardization and amount of available codification increases, this aspect becomes clearer in terms of how to operate.
Process monitoring can play a key role in strengthening the reliability of Additive Manufacturing in nuclear environments. Technologies such as optical tomography (OT) fingerprinting enable layer‑by‑layer monitoring during the build process, creating a comprehensive digital record of part production. This increases transparency and supports verification against defined quality requirements. By providing traceable, data‑driven evidence of process stability and repeatability, OT fingerprinting can facilitate qualification and help accelerate the adoption of AM within highly regulated industries such as nuclear.
Additive Manufacturing as an Early Engineering Enabler, Not Only a Manufacturing Tool
The impact of Additive Manufacturing in the nuclear sector depends strongly on when it is introduced in the lifecycle of a component or system. If AM is applied only at the end as a replacement manufacturing method, its contribution is largely limited to availability and lead time reduction. When AM is introduced earlier—already within the engineering and design phases—it can fundamentally influence how components are conceived, validated, and evolved.
Especially in a nuclear context, where design changes later in the lifecycle are costly and difficult to justify, early design decisions have a disproportionate impact. AM allows engineers to explore functional integration, optimized flow paths, material reduction, material selection or material-efficient geometries at a much earlier stage – supported by rapid iteration and physical validation. As a result, engineering decisions become more data-driven and less constrained by legacy manufacturing assumptions.
This shift is particularly relevant for next generation reactor concepts, but it also applies to the modernization of existing plants. When AM-supported engineering is introduced early, innovation does not rely solely on prototyping speed, but on the ability to rethink components holistically while already considering qualification, inspection, and traceability requirements. In this way, Additive Manufacturing becomes an engineering enabler that shapes development pathways long before production begins.
Next Generation Reactors: Why AM Expands Innovation Freedom Without Compromising Safety
Alongside securing the existing nuclear fleet, development efforts are increasingly focused on Small Modular Reactors (SMRs) and Generation IV reactor concepts. These designs typically pursue higher system integration, compact layouts, simplified balance‑of‑plant architectures, and advanced cooling and material concepts. Additive Manufacturing can support these ambitions by enabling the early evaluation of highly integrated components, compact assemblies, and complex internal geometries that are difficult or impractical to realize with conventional manufacturing, while also allowing products to be designed with a more agile and resilient future supply chain in mind – improving speed and parts availability. Expectations must nevertheless remain realistic. Development cycles for SMRs and Generation IV reactors are defined by extensive analysis, testing, and qualification and cannot be shortened by bypassing regulatory requirements. However, AM can significantly enhance early research and concept phases. Rapid prototyping, functional demonstrators, and geometry‑driven iteration allow design assumptions, such as flow behavior, thermal performance, or functional integration, to be validated much earlier in the development process.
This reinforces the central role of qualification. When additive designs for SMRs and advanced reactor concepts are aligned from the outset with testability, process stability, inspectability, and evidence generation, innovation can progress in parallel with regulatory readiness. In this way, Additive Manufacturing does not reduce safety margins, but expands engineering freedom within a framework that remains fully compatible with the stringent safety and qualification requirements of next‑generation nuclear systems.
Conclusion: AM in the Nuclear Sector – Between Ambition and Feasibility
At the end, Additive Manufacturing responds to real challenges in the nuclear industry: obsolescence, spare part availability, maintenance pressure, and the demand for safety-relevant performance improvements. At the same time, it offers potential to further enhance efficiency and enable innovation in emerging reactor concepts such as Small Modular Reactors (SMRs) and Generation IV systems, where new design approaches and advanced manufacturing capabilities play an increasingly important role.
The good news is that qualification is demanding, but manageable—provided that AM is introduced strategically, step by step, in a data-driven manner, and along application fields that are both regulatorily and operationally realistic. This approach is further supported by ongoing standardization and codification efforts, which continue to create a clearer framework for industrial adoption.
At the end, Additive Manufacturing responds to real challenges in the nuclear industry: obsolescence, spare part availability, maintenance pressure, and the demand for safety‑relevant performance improvements.
[1] https://www.lesechos.fr/industrie-services/energie-environnement/nucleaire-quel-age-ont-nos-centrales-1140104
[2] 3D printing – cutting time, cost, consumption, and CO2 emissions – Equinor
[3] Source: neimagazine.com/news/3d-printed-nuclear-fuel-parts-tested-in-alabama-power-plant/ and AM in Energy: Exxon and Westinghouse Scale 3D Printing | EOS | EOS GmbH
Author: Paula Kainu, Industry Manager Energy
