2003 Fiscal Year Final Research Report Summary
Enhancement of current density in superconducting fusion magnets by a copper-clad stainless-steel conduit
| Project/Area Number |
14580531
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Nuclear fusion studies
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| Research Institution | National Institute for Fusion Science |
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Principal Investigator |
TAKAHATA Kazuya National Institute for Fusion Science, Department of Large Helical Device Project, Associate Professor, 大型ヘリカル研究部, 助教授 (10216773)
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| Co-Investigator(Kenkyū-buntansha) |
TAMURA Hitoshi National Institute for Fusion Science, Department of Large Helical Device Project, Research Associate, 大型ヘリカル研究部, 助手 (20236756)
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| Project Period (FY) |
2002 – 2003
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| Keywords | Fusion / Superconducting magnet / Cable-in-conduit conductor / Quench / Copper-cladding / High current density / Hotspot temperature |
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| Research Abstract |
1.The hotspot temperature is one of the most important design criteria for cable-in-conduit conductors. In general, the amount of copper, as a stabilizer, in a bundle is determined by the allowable hotspot temperature, which contradicts to have a high current density in the conductor. In this study, a conductor with a copper-clad conduit is proposed. Current sharing between the bundle and copper cladding can reduce the current in the bundle during a quench. This reduces the hotspot temperature.
2.To evaluate temperature rise in a quenching cable-in-conduit conductor, we measured the thermal contact conductance between the bundle and the conduit using two experimental techniques. First, a current was applied to a short conductor cooled to liquid nitrogen temperature. The conductance, obtained from the temperature difference between the bundle and the conduit during temperature rise, was nearly independent of temperature. In the second experiments, conductance was measured under surface pressure at room temperature. The results confirmed that the conductance is strongly affected by the surface pressure. The effect of the conductivity of ambient gas was relatively small. From these results, we conclude that it is necessary to measure the conductance under a surface pressure equivalent to the expected electromagnetic force. The estimation of the thermal contact conductance is therefore considered difficult at the design phase.
3.The effect of copper cladding was analyzed for simulated conductors using zero-dimensional heat-balance equations. The simulated conductors have a circular cross-section with a diameter of 50 mm and a 1-mm-thick copper cladding outside a stainless-steel conduit. The analyses demonstrated the possibility of reducing the hotspot temperature even though high thermal resistance exists between the bundle and conduit.
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Research Products
(4 results)
