New technique advances metal powder technology for nuclear components
Metals research institute Swerim has successfully completed a three-year research project with a focus to provide an improved way to manufacture powder-based components for nuclear power plants. “The number of suppliers of using conventional techniques for the manufacture of monolithic nuclear components is limited, resulting in long lead times and restricted competition in the marketplace. Therefore, there is a great demand for developing alternative and complementary manufacturing methods,” says Irma Heikkilä, project manager.
The research team at Swerim has collaborated closely with the currently operating three Swedish nuclear plants and with one of the world's largest constructor of nuclear plants from France. Hot isostatic pressing (HIP) as a method to manufacture the large components for nuclear power plants is an interesting alternative to the conventionally used methods. Many positive attributes are connected to the HIP technology such as reduced safety assurance costs, extended operating lifetimes and possibility to increase power feed rates. An important complication of powder HIP technology has been the oxygen content of the material that can impair the toughness under impact loading.
However, a recently finished research project under the lead of Irma Heikkilä at Swerim has developed a method to reduce the oxygen content of PM-HIP materials. A technique has been developed that can be integrated into the PM HIP manufacturing process, resulting in minimal and homogeneous oxygen content in the final product, even if that the amount of powder is as high as several tons.
“In this case, the actual finished component weighs several tons. Although we have not worked with these dimensions, we have worked in industrial scale in our project. We still have a long way to go before the method can be practically applied and this must be made together with regulatory authorities. However, we have demonstrated initially that it is possible to create large components with extremely good material properties for nuclear plants by means of powder metallurgy. I believe there is strong interest in the industry for developing this technology over the long term,” concludes Irma Heikkilä, Swerim.
The project “Reduced oxygen content of PM HIP materials for nuclear power plants” has been funded by Vinnova. The budget is 3.6 million SEK and the project period is 2017 – 2020. Partners: MTC Powder Solutions, Carpenter Powder Products, Quintus Technologies, Framatome, Ringhals, Forsmarks Kraftgrupp and OKG Uniper.
Bild: I bilden syns en stor het isostatisk press från Quintus Technologies. HIPpen är den största i världen och finns i Japan hos Metal Technology Co. Ltd. (MTC), moderföretag till MTC Powder Solutions.