Abstract Body

From the perspective of carbon neutrality, expectations are rising for the early realization of nuclear fusion power generation. In addition to large-scale projects led by the government, venture companies are also conducting research and development of small nuclear fusion power reactors. On the other hand, it is essential that large-scale power generation, such as existing thermal power generation and future nuclear fusion power generation, coexist and prosper with renewable energy sources such as solar and wind power, whose output fluctuates. One solution is the technology that uses hydrogen to adjust electricity supply and demand. Until now, it was assumed that the heat obtained from nuclear fusion would be used as electrical energy, but since it is possible to efficiently produce hydrogen using the thermal output from a nuclear fusion reactor, it is important to consider new output forms of nuclear fusion technology, which has been focused solely on electrical output, in order to aim for the social implementation of nuclear fusion technology. In addition, by handling the obtained hydrogen in the form of liquid hydrogen, the cold energy can be effectively used for cooling superconducting equipment, making it possible to adjust the supply and demand of electricity repeatedly in a short period of time in Superconducting Magnetic Energy Storage system (SMES). In addition, it is expected that the long-term storage of large-capacity energy using liquid hydrogen will contribute to the seasonal supply and demand adjustment required for the stabilization of the power system in the future.

In this presentation, I will explain the compatibility between hydrogen and nuclear fusion, and the necessity of using liquid hydrogen to cool large superconducting coils. Next, I will introduce the research objectives of the Applied Superconductivity and Cryogenics Unit (ASC Unit), a new organization at the National Institute for Fusion Science. The research objective of the ASC Unit is to further activate the genes of superconductivity and cryogenics specialized for nuclear fusion development, which have been cultivated through the Large Helical Devise (LHD) project and joint research with universities that the National Institute for Fusion Science has been working on, and to develop new superconductivity and cryogenics engineering that includes "hydrogen," which is an accelerating driving force for realizing a sustainable society, and aims for high safety and reliability. We will also introduce that by feeding back the progress of superconductivity and cryogenics engineering to next-generation nuclear fusion engineering, we aim not only to create a new situation in nuclear fusion research, but also to contribute to the further development of other big sciences. In addition, we will introduce some hydrogen-related results and plans as concrete research results. As results, we will introduce the study of magnetic refrigeration that can realize hydrogen liquefaction with high efficiency[1], and the results of the evaluation of the current characteristics when liquid hydrogen cooling of large-capacity high-temperature superconducting conductors[2]-[4], which is being promoted by the National Institute for Fusion Science, is assumed. Plans include introducing research and development into producing hydrogen from water using the heat of nuclear fusion, and research into using liquid hydrogen to achieve highly efficient enrichment of deuterium, the fuel for nuclear fusion.

References

[1] Naoki Hirano et al., “Development of Static Magnetic Refrigeration System Using Multiple High-Temperature Superconducting Coils”, IEEE Transactions on Applied Superconductivity, vol. 32, no. 6, Sep. 2022, 0500105, Doi:10.1109/TASC.2022.3152456

[2] Nagato YANAGI et al., " Progress of HTS STARS Conductor Development for the Next-Generation Helical Fusion Experimental Device”, Plasma and Fusion Research 17 (2022) 2405076

[3] Yoshiro NARUSHIMA et al., " Test of 10 kA-Class HTS WISE Conductor in High Magnetic Field Facility, Plasma and Fusion Research 17 (2022) 2405006

[4] Yuta Onodera et al., " Development of a compact HTS-FAIR conductor for magnet application, IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY 33, No.5 (2023) 4801004

Acknowledgment

Part of the research presented here is supported by the National Institute for Fusion Science's collaborative research program.

Figure 1. Goals of the Applied Superconductivity and Cryogenics Unit

Keywords: Large scale superconducting coil, Advanced superconducting conductor, Liquid hydrogen, Magnetic refrigeration, Carbon neutral