3D-printed components secure the future of nuclear power

Additive manufacturing, usually abbreviated to AM, is finding more and more applications. Using a 3D printer and a digital drawing, components are manufactured by adding layers upon layers of, for example, metal powder, hence the name additive manufacturing. Each layer is melted in place using laser technology to finally form a finished component. 

Björn Forssgren, Vattenfall specialist in metallic materials, inspects 3D-printed pipe supports before installation at Ringhals 3.

Within manufacturing industries, more and more products are being produced in this way, for example in the automotive, aerospace and defence industries, or in the medical technology area to manufacture customised hearing aids, implants such as hip joint balls, and more.

Spare parts for nuclear power

Additive manufacturing is also a good way to produce spare parts and components for nuclear power plants. Sweden has six nuclear reactors, all built in the 1970s and 1980s. Vattenfall, which owns five of these, has initiated extensive projects to extend their operating life from 60 to 80 years. This means that a large number of components will need to be replaced with new ones. However, there are challenges in obtaining spare parts and qualified suppliers. This can result in long lead times and high costs and, in the worst case, entire components may have to be replaced because spare parts are not available. 

The availability of spare parts is further limited by the fact that some industry giants have bought up subcontractors to secure supply chains for their reactors.

“The development means that we see a risk of being deprioritised when we need to obtain components at short notice. By using AM, we can control and prioritise production ourselves, which would ultimately contribute to increased availability for our production units, meaning more fossil-free electricity production,” says Björn Forssgren, metallic materials specialist at the Ringhals nuclear power plant and also responsible for this area within Research and Development at Ringhals.

With this in mind, Ringhals decided already in 2017 to participate in the financing of a 3D printer together with four other companies in the region. The collaboration is managed by RISE, Research Institutes of Sweden, and currently consists of 21 companies working together on areas such as technology development. 

“We saw the potential of AM technology early on, and in many industries this is already the new normal. The primary thing for us is that the technology is incredibly flexible; we can manufacture pretty much anything we want: pipes, valves, pump housings, internal parts for these, and there are no limitations in terms of materials either; virtually all types of alloys can be used,’ says Björn Forssgren. 

At least as good as traditional components

AM is a new technology, and much of the work done has been about verifying the manufacturing and materials and carefully studying and checking the structural integrity of the 3D-printed parts, i.e. their strength, durability, resistance over time, and so on. And the results are very positive:

“AM is a highly controlled manufacturing process and all our studies show that components manufactured in this way are at least as good as those manufactured traditionally. We have strict requirements and use the technology to ensure that the structural integrity is the same, and in many cases better even better than traditional spare parts.“

Today, AM-manufactured components are installed in all three Swedish nuclear power plants; Ringhals on the west coast, Forsmark on the east coast north of Stockholm and Fortum-owned Oskarshamn in the south-east. So far, this applies to certain components that are located where they are not exposed to high pressure. However, international work is underway to develop standards for AM-manufactured parts that are subjected to pressure.

‘We hope that such a standard will be ready in the near future. Once it is ready, we can really start looking at installing components in our plants.’ 

This 3D printed top plate supports the fuel rods in a fuel assembly and is an example of a AM manufactured component now installed in Swedish nuclear power plants.

The next step could therefore be to set up an inhouse 3D printing facility. This could supply other nuclear power plants, and even other types of power generation within Vattenfall, with spare parts. Björn Forssgren concludes:

“The plants are not getting any younger, and AM is a tool for achieving our availability targets and reducing the risk of production disruptions. We want to work proactively with components that are considered to be at risk. By creating virtual warehouses of digital CAD models, we can 3D print new components when the need arises. Every planned shutdown is extremely expensive, affects availability and also damages confidence in nuclear power.”

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