2023 Fiscal Year Annual Research Report
原子炉配管内壁補修技術のための革新的コールドスプレーノズルの開発とその評価
| Project/Area Number |
22KJ0254
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| Allocation Type | Multi-year Fund |
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| Research Institution | Tokyo University of Science |
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Principal Investigator |
Meng Yuxian 東京理科大学, 工学部, 助教
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| Project Period (FY) |
2023-03-08 – 2024-03-31
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| Keywords | spiral nozzle design / cold spray / pipe maintenance / inner wall / neural networks / CFD calculation / FEM analysis / laser metal deposition |
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| Outline of Annual Research Achievements |
To maintain the inner wall of nuclear piping, a spiral cold spray nozzle was developed and utilized to spray the protective coating on the pipe's inner wall. Specifically, the effects of the spring lift angle, expansion ratio, and mean coil diameter were studied. The neural network was applied for the optimization process, indicating a high efficiency and accuracy to design the spiral nozzle. Besides, a new method based on the energy conservation principle was proposed to design/optimize the cold spray nozzle. The cold spray nozzle optimized by this new method could significantly improve the deposition efficiency of 304L stainless steel compared with the conventional nozzle. In addition, the cold spray was also employed to seal leaks in piping. The experimental results demonstrating high efficiency in sealing water leaks. Additionally, the Perfluoroalkoxy Alkane (PFA) coatings were deposited using the cold spray to further protect the pipe's inner walls. A heat treatment process was suggested to improve the bonding strength of the PFA coatings. Moreover, the laser metal deposition (LMD) process was explored for repairing damaged components. In particular, the effects of the LMD conditions (i.e., laser power, traverse speed, and initial substrate temperature) and removal process on the residual stress distribution and deformation evolution during LMD repairing were clarified.
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