Expanding Nuclear Power, Layer by Layer

In 2016, a broad political agreement was reached to make all energy production renewable by 2040, bringing nuclear power back into the spotlight of public debate. Since then, the goal of expanding the nuclear energy sector has gained even more traction, especially with the government's roadmap for new nuclear power unveiled in the fall of 2023. However, after years of phasing out nuclear facilities, the industry now faces a significant challenge.

"The main issue is the availability of suppliers and various components that meet the nuclear specific requirements," says Björn Forssgren, Senior Specialist Materials Technology at the nuclear power plant Ringhals, and continues:

"The requirements for nuclear power components are complex. There are several different demands that need to be met, both regulatory and company-specific. The regulatory requirements are typically national. During the fifty to sixty years that nuclear power has been around, the number of qualified and approved suppliers has decreased, and now we are facing a situation where they are hard to come by. Suppliers and obsolete components have caused considerable uncertainty for us."

The nuclear industry holds a societal responsibility to provide electricity to the community, a responsibility expected to grow in line with the government's goal of new nuclear power equivalent to at least two large-scale reactors by 2035. This means that both current and future reactors must have access to the components necessary to ensure operational stability. Can that be guaranteed, if suppliers are scarce? 

New technology, new supply chains

In 2017, the year after the energy agreement was reached, Björn Forssgren came into contact with RISE.

"Naturally, we had heard about 3D printing and had been producing plastic prototypes for several years. But when we noticed that the metal side of the technology was starting to mature, we recognized it as a potential solution for us. We joined the RISE-coordinated industrial collaboration Concept Line, where our understanding of the technology's possibilities deepened. Following that, it felt like a natural step for us to participate in RISE's next initiative, the Application Center for Additive Manufacturing."

The range of components in a nuclear power plant is vast. It includes small, medium, and very large components made from various types of materials. The initial focus of Ringhals was to look into the possibility of producing qualified test blocks for non-destructive testing (NDT). The encounter with 3D printing, or additive manufacturing (AM), in metal generated several insights. One key realization was that AM, as an emerging manufacturing technology, has entirely different supply chains – supply chains that are less vulnerable.

From drawing board to finished product

A variety of pilot projects were soon launched. These projects explored the potential to print everything from weld heads to compressor covers. As of today, two of these initiatives have successfully produced components that have gone through the entire process, from design to finished and installed product.

"During the spring and summer of 2024, we installed anti-vibration supports, which were printed at RISE, in Ringhals 3 and Ringhals 4, and they are now fully integrated into the plants. Additionally, we have recently collaborated with the French nuclear reactor company Framatome to install 3D-printed anti-debris filters in four of the fuel bundles at Ringhals 4. The plan is for the filters, mounted onto the fuel bundles' bottom nozzle, to be exposed over a complete fuel cycle that will last approximately five years,” says Björn Forssgren.

Ringhals has also developed its own quality assurance protocols, a qualification process for the PBF-LB (Powder Bed Fusion-Laser Beam) technology and the 316L material (stainless austenitic steel), based on the insights they have acquired through years of collaboration with RISE, suppliers, and industry partners in the center.

"The access to the expertise at RISE, along with the opportunity to actively apply the technology for our own studies, has been incredibly important for us. Our collaboration has provided us with a deep understanding of the manufacturing process and its various stages, allowing us to ensure that we construct components in the best possible manner to meet our specific quality standards. Additionally, through the center membership, we have been able to exchange ideas with other industry sectors and benefit from their perspectives. This has been valuable. I believe we have all learned a great deal along the way,” says Björn Forssgren.

Additive manufacturing gaining ground

Additive manufacturing has emerged as a promising option for producing various components within the nuclear industry, although further advancements are necessary, especially in post-processing. Björn Forssgren believes that we are merely at the start of a journey with no end in sight, where additive manufacturing will increasingly become the standard rather than the exception.

“Powder Bed Fusion (PBF) and Directed Energy Deposition (DED) are both promising technologies for the nuclear industry. The primary limitation currently lies in the dimensions, particularly for PBF, which can only produce smaller components at this time. However, technological advancements on the hardware side are progressing rapidly with the goal of enabling the manufacturing of larger components using these technologies. For components with the correct dimensions, I believe PBF will emerge as one of the major players in terms of manufacturing. The technology must, of course, mature, and standardization and regulations need to be put in place, but it's merely a matter of time. Additive manufacturing is set to become standard in the future.” 

Photo source: Vattenfall / Ringhals