Chinese Researchers Use SLM 3D Printing Technology to Fabricate Nuclear Components Out of Steel

3D printed part for nuclear fusion test reactor. [Image: Dr. Leifeng Liu, University of Birmingham]

3D printing technology is a good manufacturing technique for fabricating complex components for these types of industrial applications, as it is capable of formulating complicated structures.

At the Chinese Academy of Sciences, a team of researchers is using anti-neuron irradiated steel (CLAM steel) as a raw material to build walls and trial components for a nuclear fusion reactor.

The research, including an analysis of the material’s performance, was recently published in a paper, titled “Microstructure anisotropy and its effect on mechanical properties of reduced activation ferritic/martensitic steel fabricated by selective laser melting,” in the Journal of Nuclear Materials. Bo Huang, Yutao Zhai, Shaojun Liu, and Xiaodong Mao, all with the academy’s Key Laboratory of Neutronics and Radiation Safety at the Institute of Nuclear Energy Safety Technology (INEST), co-authored the paper.

The abstract reads, “Selective laser melting (SLM) is a promising way for the fabrication of complex reduced activation ferritic/martensitic steel components. The microstructure of the SLM built China low activation martensitic (CLAM) steel plates was observed and analyzed. The hardness, Charpy impact and tensile testing of the specimens in different orientations were performed at room temperature. The results showed that the difference in the mechanical properties was related to the anisotropy in microstructure. The planer unmelted porosity in the interface of the adjacent layers induced opening/tensile mode when the tensile samples parallel to the build direction were tested whereas the samples vertical to the build direction fractured in the shear mode with the grains being sheared in a slant angle. Moreover, the impact absorbed energy (IAE) of all impact specimens was significantly lower than that of the wrought CLAM steel, and the IAE of the samples vertical to the build direction was higher than that of the samples parallel to the build direction. The impact fracture surfaces revealed that the load parallel to the build layers caused laminated tearing among the layers, and the load vertical to the layers induced intergranular fracture across the layers.”

Researchers completed a trial production of fusion reactor cladding components using raw, 3D printed CLAM steel. This was done in order to test how feasible 3D printing technology would be in making the reactors, and other advanced nuclear energy system components.

Several experiments were conducted, as the researchers 3D printed neutron-irradiated steel samples for a reactor’s wall for the first time. According to the results, the material’s density reached 99.7%, which is comparable to traditional CLAM steel material; this means that the prototype met its design requirements.

The study also showed that SLM 3D printing, and its “directional solidification characteristics,” resulted in differences between the steel’s properties and microstructure. However, by using melt pool nucleation optimization and scanning scheme optimization, these differences can be greatly lowered, or even eliminated altogether.

The research paper shows that 3D printing can be used in the production of these complex nuclear fusion reactors and other nuclear power system components. They also prove how strong China’s R&D capabilities are in terms of 3D printing components for advanced nuclear energy systems.

Discuss this and other 3D printing topics at 3DPrintBoard.com or share your thoughts below.