Additive manufacturing, also known as 3D printing, is delivering faster innovation, lower costs, and enhanced safety to the nuclear sector.
As the global energy sector transitions toward low-carbon solutions, nuclear power remains a vital pillar of sustainable electricity generation. In Sweden and beyond, nuclear energy has long provided reliable power with minimal carbon emissions. However, the industry faces persistent challenges: ageing infrastructure, high costs of new builds, and the need for more flexible, efficient manufacturing methods.
3D printing a nuclear reactor?
Also referred to as 3D printing, additive manufacturing (AM) enables the creation of complex geometries layer by layer, offering design freedom and manufacturing flexibility. For the nuclear sector, this means faster innovation, lower costs, and enhanced safety. Though the basic concept of AM of components for nuclear reactors is similar to commercial plastic filament printers, where parts are built with melted material layer by layer, metal 3D printing involves much higher temperatures, uses fine metal powders, and relies on powerful lasers or electron beams to fuse the material together. The material used can be familiar and well understood, such as the ubiquitous 316 stainless steel, but the unknowns still present in AM components remain a hurdle for their adoption into the nuclear industry.
Breathing new life into ageing reactors
Many of Sweden’s nuclear reactors were commissioned between the late 1970s and mid-1980s. As these facilities age, sourcing replacement parts for outdated systems becomes increasingly difficult due to discontinued manufacturing lines and obsolete designs. AM offers a solution by enabling the reproduction of legacy components that are no longer commercially available. Through reverse engineering and digital modelling, AM can recreate complex parts with high precision, ensuring the continued operation and safety of ageing infrastructure.
While AM has seen widespread adoption in aerospace and medical industries, its use in nuclear applications is still emerging. Components manufactured using AM are already being deployed in non-safety-critical systems within nuclear power plants. However, as the nuclear industry is one of the most highly regulated sectors in the world, broader adoption of new technologies can be slow, especially for components exposed to the reactor core. Before any new material or component can be used in a nuclear reactor, it must undergo a multi-step qualification and approval process, beginning with laboratory testing under simulated conditions, followed by experiments in materials testing reactors. This data is then analysed and submitted to regulatory authorities, who conduct a thorough review.
Components produced by AM are no exception. Unlike conventionally produced materials, which benefit from decades of in-reactor testing and post-irradiation analysis, AM materials, even with identical compositions to their casted counterparts, lack a comparable foundation. This is particularly relevant for components exposed to neutron irradiation, high temperatures, and reactor coolant environments, where failure mechanisms can be heavily influenced by the microstructure of the material.
AM materials typically exhibit a distinct microstructure compared to conventionally cast materials due to their layer-by-layer fabrication process and rapid solidification rates, and often show irregular grain structures, porosity, or even unmelted powder particles. These features can significantly influence corrosion resistance and behaviour under irradiation.
The state of the state-of-the-art
The characterisation of AM parts for nuclear reactors is still in the early stages. Ion irradiation is often used as a first stage proxy for neutron damage in materials testing, as the damage incurred is similar, but without the risk of activating the irradiated components which makes analysis more difficult and more expensive.
The irradiated materials are investigated using the most advanced microscopy techniques, including atom probe tomography (APT). With near-atomic resolution, APT investigates the damage incurred in these materials by irradiation, allowing for a more comprehensive characterisation.
Looking forward
Additive manufacturing is not just a stopgap for ageing infrastructure – it’s a key enabler of next-generation nuclear technologies. However, realising the potential of AM in nuclear requires continued investment in research, testing, and regulatory development, which can only be done through close collaboration between academia, industry, and regulatory bodies, as well as public support. A prime example of this collaborative approach is Sweden’s ANItA Competence Center (Academic-industrial Nuclear technology Initiative to Achieve a sustainable energy future). Hosted by Uppsala University in partnership with Chalmers, KTH, and major industry players like Vattenfall and Westinghouse, ANItA is a national initiative dedicated to supporting the safe and efficient deployment of small modular reactors (SMRs). The center funds cutting-edge research into materials science, licensing, public engagement, and reactor design – areas where additive manufacturing plays a pivotal role. The flexibility and rapid prototyping capabilities of AM align naturally with the modular, scalable nature of SMRs, making them a powerful combination for the future of nuclear energy.
As the world seeks resilient, low-carbon energy solutions, the convergence of additive manufacturing and advanced nuclear technologies offers a compelling path forward. With initiatives like ANItA, Sweden is positioning itself at the forefront of a nuclear renaissance – one that is safer, smarter, and more sustainable. The future of nuclear energy may well be printed, layer by layer.
Please note, this article will also appear in the 23rd edition of our quarterly publication.
