Connection structure for superconducting cables, method for laying the same, and method for vacuuming connection structure for superconducting cables

A connection structure for superconducting cables for connecting superconducting cables each having a cable core housed in a thermal insulation tube with a cooling medium by an intermediate connecting part, the cable core being provided with a former and a superconducting conductor layer, wherein

• the thermal insulation tube has a double-structure constituted of a thermal insulation internal tube and a thermal insulation external tube, and the intermediate connecting part has a double-structure constituted of an outer container and an inner container,
• the thermal insulation internal tube and the thermal insulation external tube penetrate a wall surface of the outer container and introduced at least up to a wall surface of the inner container, an end to be introduced of the thermal insulation internal tube and an end to be introduced of the thermal insulation external tube are joined so as to seal each of a region between the thermal insulation internal tube and the thermal insulation external tube and a region between the outer container and the inner container,
• at an introduction portion of the thermal insulation external tube to be positioned inside of a wall surface of the outer container, a corrugated tubular part having a tube wall of a thickness thinner than a thickness of the thermal insulation external tube outside of the wall surface is provided, and
• the thermal insulation tube and the intermediate connecting part are provided with vacuum outlets, respectively, for vacuuming respective insides thereof.