Siemens prints part for Krško plant

A 3D-printed impeller has been in use in a pump at Slovenia's Krško plant since January. Siemens, which produced the component, said this marks "the first successful commercial installation and continuing safe operation" of such a part in a nuclear power plant.

A 3D-printed impeller has been in use in a pump at Slovenia's Krško plant since January. Siemens, which produced the component, said this marks "the first successful commercial installation and continuing safe operation" of such a part in a nuclear power plant.

From left to right, the original, obsolete impeller; the 3D-printed prototype; and, the resulting 3D-printed replacement part (Image: Siemens)

Plant operator Nuklearna Elektrarna Krško (NEK) required a replacement metallic, 108mm-diameter impeller for a fire protection pump that is in constant rotating operation. The orginal part had been in operation since the plant was commissioned in 1981. However, the manufacturer of that part is no longer in business.

Siemens said its team of experts in Sloveina reverse-engineered and created a "digital twin" of the part. A 3D-printed replacement part was then produced at the company's additive manufacturing facility in Finspång, Sweden.

3D printing is a way of manufacturing metal or plastic parts directly from design data, using lasers to fuse together high-performance materials layer by layer. The technique enables components, including one-off specialist items, to be made relatively quickly from 3D design data, which can even be obtained by scanning an existing item. Metal parts can be printed in a wide range of materials including titanium, stainless steel and brass, to a high resolution.

Siemens said "extensive testing" of the 3D-printed impeller was carried out jointly by Siemens and NEK over several months to ensure it meet Krško's "stringent quality and safety assurance requirements". Additional testing at an independent institute, including a CT scan, showed the material properties of the replacement part were superior to those of the original part, Siemens said.

The replacement impeller has been operating successfully at the Krško plant since January, Siemens said today.

"Obsolete, non-OEM parts are paticularly well-suited for this new technology as they and their designs are virtually impossible to obtain," the company said. "This technology thus allows mature operating plants to continue operating and achieving or, as in the Krško case, even extending, their full life expectancy."

Siemens said it plans to continue its research and development with Krško into the use of 3D-printed parts. It said they are "looking at advancing the design of parts that are most difficult to produce using classical manufacturing techniques, such as lightweight structure with improved cooling pattern", Siemens said.

Tim Holt, CEO of Siemens Power Generation Services division, said: "We continue to push forward our investments and cutting-edge advancements in additive manufacturing and 3D printing. This achievement at the Krško nuclear power plant is another example of how the digital transformation and the data-driven capabilities we have are impacting the energy industry in ways that really matter."

3D printing technology has already found applications within other parts of the nuclear industry.

The UK's Sellafield Ltd announced in May 2014 it was working with 3D specialist companies 3T RPD and Central Scanning to create metal and plastic components, parts and one-offs to help meet the challenges of decommissioning one of the world's oldest and most complex nuclear sites. The company used 3D blue-LED scanning technology to design a replacement lid for a 40 tonne solid waste transfer container.

Researched and written
by World Nuclear News