JPH06275144A - Superconducting stranded cable - Google Patents

Abstract

PURPOSE:To easily and accurately analyze the cooling characteristic of a superconducting coil, grasp the cooled state of the coil at the start of actual operation, and control the temperature of the coil during operation. CONSTITUTION:A superconducting stranded cable 1 constituting a superconducting coil is so formed that at least one of superconducting wires 2 is replaced by an optical fiber 3. The optical fiber 3 is inserted into a protective pipe 4. By coiling the superconducting stranded cable 1 a temperature distribution measuring system with the optical fiber 3 as a temperature sensor is constructed and the above purpose can be accomplished.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superconducting stranded wire used as a coil wire in a superconducting magnet for various applications including superconducting generators and nuclear fusion experimental reactors.

[0002]

2. Description of the Related Art For example, in a superconducting magnet, when the coil heats up during operation and the temperature rises, it causes quenching and burning. In addition, if quenching occurs, problems may occur in the cooling system or the like.

For this reason, a method is employed in which thermometers such as thermocouples are attached to the coil during winding or after winding, at various points on the coil surface and the cooling state of the entire magnet is monitored to utilize this data for actual operation. Has been.

[0004]

According to the above-mentioned conventional method, a great deal of labor is required for mounting the thermometer, and the installation of the thermometer also makes it difficult to handle it at cryogenic temperatures.

Further, when an electric current is applied to the magnet, the measuring portion is placed in a magnetic field atmosphere, and a voltage harmful to the measurement may be applied to the temperature sensor, so that accurate temperature data cannot be obtained.

Furthermore, in a superconducting magnet or the like that is repeatedly operated and stopped, a thermometer that can withstand repeated thermal history and a structure that is easy to maintain are required.

The present invention is intended to provide a superconducting stranded wire for a superconducting coil which solves these problems.

[0008]

The superconducting stranded wire of the present invention for solving the above problems has a structure in which at least one of a plurality of superconducting element wires to be twisted with each other is replaced with an optical fiber. The optical fiber is used as a temperature sensor of the optical fiber temperature distribution measuring system.

[0009]

The superconducting coil is cooled in order from the portion in contact with the refrigerant such as liquid nitrogen and liquid helium. that time,
The optical fiber twisted into the coil wire is also cooled to the same temperature as the superconducting element wire. Therefore, by constructing a temperature distribution measurement system that uses this optical fiber as a temperature sensor, the process of cooling each part of the superconducting coil It is possible to measure temperature changes over time and temperature changes during operation.

As described above, if the optical fibers are twisted together at the time of manufacturing the twisted wire, a superconducting coil having a built-in temperature sensor can be obtained only by winding the wire, and the labor for mounting the thermometer is unnecessary.

Further, since the optical fiber is not affected by the surrounding magnetic field at all, the reliability of measurement can be secured.

Further, if the optical fiber is housed in a protective pipe and twisted, as will be described later, little attention is paid to maintenance.

[0013]

1 and 2 show an example of a superconducting stranded wire of the present invention. The illustrated superconducting twisted wire 1 has a twist structure of 1 + 6, and is usually constructed by twisting seven superconducting wires 2, but here, the central wire is replaced with an optical fiber 3 containing a protective pipe. There is. As the protection pipe 4, a pipe having the same outer diameter as that of the superconducting wire 1 is used, and therefore, there is no fear that the cross-sectional shape of the stranded wire 1 will collapse.

In order to confirm the effect, the outer diameter is 1.4 mm,
A stainless steel pipe with an inner diameter of 1.0 mm is placed with a GI-type quartz optical fiber inserted into the center of the element wire, and a wire diameter of 1.4
Six 6 mm / Cu / NbTi superconducting element wires were twisted together to obtain a superconducting twisted wire having the structure shown in the figure. And this stranded wire 1
By winding a coil on a bobbin to make a superconducting coil, and using a temperature distribution measurement system that uses a pre-twisted optical fiber as a sensor element, we investigated the temperature distribution of each part of the superconducting coil during simulated cooling, and obtained accurate data. , It was useful for the analysis of cooling characteristics.

[0015]

As described above, when the superconducting stranded wire of the present invention is used, the temperature distribution over the entire area of the superconducting coil can be accurately measured without any trouble, and the cooling characteristics can be analyzed.
It can greatly contribute to grasping the cooling status at the start of actual operation and temperature management during operation.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a superconducting stranded wire of the present invention.

FIG. 2 is a perspective view of the same stranded wire.

[Explanation of symbols]

 1 Superconducting stranded wire 2 Superconducting element wire 3 Optical fiber 4 Protective pipe

Claims (1)

[Claims] 1. A superconducting twisted wire in which at least one of the plurality of superconducting wires twisted together is replaced with an optical fiber.