Advances that allow metals and high-tech composites to be 3D printed have already landed the technology in the aerospace and medical arenas. Additive manufacturing is also being seen as a key technology for producing small, safe next-generation nuclear reactors.
The latest example comes from Seattle-based Ultra Safe Nuclear Corp., which has licensed a novel 3D-printing technology from Oak Ridge National Laboratory. The method will allow the company to make nuclear reactor components not with metals but with technical ceramics that are much more resistant to radiation and extreme temperatures, enabling them to speed up the development of safe, affordable next-generation reactors.
USNC is making micro modular reactors that the company says should cost tens of millions of dollars to deploy as opposed to the billions needed for today’s large reactors, with plans to deploy its first reactor by 2026. The company, which is also developing compact reactors for nuclear-powered rockets, says its safe design relies on a rugged fuel made of microscopic ceramic-coated uranium fuel particles that are encased in a silicon carbide matrix.
Oak Ridge’s 3D-printing technique combines binder jet printing with a special ceramic production process that will allow the design of new complex geometries for certain parts that were previously impossible.
Silicon carbide, a type of engineering ceramic, is already used in tank armor and specialty electronics and aerospace applications. But forging the complicated shapes of reactor components with such ceramics is extremely difficult using conventional methods like machining or casting.
The Oak Ridge lab’s 3D-printing technique combines binder jet printing with a special ceramic production process that will let USNC print complex geometries from silicon carbide.
Leveraging the technology will not only enable faster and more economical production of reactor components, it should also allow the design of new complex geometries for certain parts that were previously impossible, says Kurt Terrani, executive vice president of USNC's Core division.
“USNC’s value proposition is summarized in two points,” he says, “designing inherently safe and highly advanced nuclear-energy systems that are fueled with highly safe and temperature-resistant materials.”
The newly licensed 3D-printing technology will become a key part of USNC’s manufacturing process, Terrani says. The company will use it to make the silicon carbide shells for its nuclear fuel and also to produce nonfuel structural components for its reactors. The advanced ceramic-based reactor systems should be safer than traditional ones that primarily use metallic components.
“Silicon carbide 3D printing is a new technology that offers new possibilities, but it will also require thorough vetting to ensure the resulting materials and their performance meet strict nuclear licensing and regulatory requirements,” he says. Fortunately, the Oak Ridge lab's researchers have extensively tested these novel 3D-printed materials outside and within nuclear reactors in recent years.
Indeed, 3D printing is not new to the nuclear industry. In 2017, Siemens became the first to install a 3D-printed part in a nuclear power plant: a small metallic part for a fire-protection water pump used at a plant in Slovenia.
Since then, others have put more, bigger 3D-printed parts in commercial reactors. In 2020, Westinghouse installed a 3D-printed fuel component in Exelon’s nuclear power plant in Illinois. And last year, the Tennessee Valley Authority’s Browns Ferry plant in Alabama got four 3D-printed stainless-steel fuel assembly brackets printed at the U.S. Department of Energy’s Manufacturing Demonstration Facility at the Oak Ridge lab.
The lab, however, is pushing the envelope with its ambitious plan to build an entirely 3D-printed nuclear reactor core. The demonstration unit of this Transformational Challenge Reactor is slated to be operational by 2024. Terrani, in fact, is the former technical director of the TCR program.
USNC plans to leverage Oak Ridge’s 3D-printing expertise by building a new pilot fuel-fabrication facility near the laboratory’s campus in East Tennessee. The partnership could be a significant boost for 3D printing in nuclear power.
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