JP2005345276A - Radiation-resistant small-sized stop plug - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure of a stop plug having sufficiently high airtightness, no function defect caused by radiation irradiation, a small space for valve loading, and a function for confirming normal operation after stop valve operation. <P>SOLUTION: This stop plug is formed by providing a low-melting-point metal tube having the same inner diameter as a pipe diameter in the middle of the pipe which is a closing object, and by arranging a metal mesh material for holding the tube, an outer container, a heater for heating the low-melting-point metal, and a thermocouple for confirming stop plug behavior. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a small stopper that has both high airtightness and radiation resistance, such as prevention of leakage of tritium gas, and can be applied even when the space for loading is small, and can be operated remotely. It is.

  In order to close the pipe with a high degree of sealing, a vacuum valve or a stopper is generally used. However, in these valves and plugs, the structure of the valve body is too large compared to the mounting pipe, and many times as much installation space as the size of the pipe is required.

  Among existing devices, solenoid valves that operate valves with small electromagnets have a relatively small installation space, but electromagnets that operate valves under radiation irradiation contain a polymer insulating material, so the valve functions. There is a problem that it has a defect that it disappears and is not reliable.

In the high energy proton accelerator, there are accelerator control devices, electromagnets (including polymer materials), particle detectors for high energy experiments, etc. around the beam line. The occurrence of damage has been one of the main causes of these failures (Non-Patent Document 1).
Kawakubo Tadashi, Numajiri Masaharu, Sami Toshiya, Radiation Exposure Measurement in PS Tunnel, Accelerator Study Note, ASN-461 (2002) p.4, High Energy Accelerator Research Organization (KEN) published (August 7, 2002)

  In addition to satisfying high airtightness, the present invention has no functional failure due to radiation irradiation, has a small space for valve loading, and has a function of confirming whether or not the valve is operating normally after the closure valve is operated. The object of the present invention is to provide a structure and operation method of a stopper plug.

  In the present invention, a test and development for solving these problems is carried out, a low melting point metal tube having the same inner diameter as the pipe inner diameter is provided in the middle of the pipe to be closed, and a metal mesh material for holding it, an outer It is the structure which has arrange | positioned the container, the heater for heating a low melting-point metal, and the thermocouple for confirming a closing stopper behavior.

  With regard to the high sealing performance holding method, a structure in which gold plating is applied to the inner surface of the stopper plug in order to improve the wettability of the low melting point metal fixing portion, and the structure can be fixed without generating a gap between the low melting point metal and the inner surface of the stopper plug. did.

  In addition, a metal mesh material for preventing the molten metal from flowing out is provided below the low melting point metal so that the molten low melting point metal is fixed at the gold plating portion, so that the molten low melting point metal does not flow out.

  With regard to installation space constraints, by implementing the closing control with a heater installed on the outer periphery of the stopper plug, the space for equipment for closing valves and stoppers, which has been used in the past, is extremely reduced and the closure is closed. Closing operation has been simplified by operating the plug as a heater.

According to the present invention, it is possible to perform sealing of tritium gas piping that requires less installation space and requires high airtightness by a simple remote operation, and it is easy to check the operation of the stopper plug itself.
In addition, when replacing internal structural members in nuclear reactors and nuclear fusion reactors, when disconnecting piping, etc., by providing the closure plug of the present invention, it is possible to easily block the leakage of tritium gas, etc. There is an advantage that can be exchanged.

An embodiment of a closure plug according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a structural diagram of the closure plug of the present invention, and FIG. 2 is a state diagram after the closure plug is actuated. Moreover, the attachment position and temperature chart of the thermocouple which confirms an operation state are shown in FIG.3 and FIG.4.

  1 is provided with a low melting point metal tube (2) having the same inner diameter as the pipe inner diameter in the middle of the pipe (1) to be closed, and a metal messy material (3) and inner surface for holding the same. It has a structure using an outer container (4) plated with gold, a heater (5) for heating a low melting point metal, and a thermocouple (6) for confirming the closing plug behavior.

As shown in FIGS. 1 and 2, the closure plug of the present invention is composed of a low-melting point metal (2) such as tin (Sn) or indium (In) that is not affected by radiation irradiation, and is connected to a pipe (1 ) A low melting point metal is melted by a heater (5) provided inside and provided outside the pipe, so that it is fixed inside the pipe and the pipe is sealed. A metal mesh material is disposed at the lower end of the low melting point metal in order to hold the low melting point metal before melting and prevent the low melting point metal from flowing out after melting.
As shown in FIG. 3, several thermocouples (T / C1 to C5) are attached to the outside of the closure plug of the present invention, and the temperature state of the low melting point metal inside the closure plug is determined by a signal from the thermocouple. In addition, it is possible to check the closed state of the piping at the closing plug by heating with a heater and melting the low melting point metal. FIG. 4 shows a temperature state measured with a thermocouple and changing with the passage of time of the low melting point metal when the pipe is closed with the closing plug.

A closure plug using tin (Sn) as a low melting point metal and a ceramic heater as a heater for heating the low melting point metal was manufactured and actually operated, and the sealing performance by the closure plug was carried out in a helium leak test. As a result, it was confirmed that the seal satisfying a helium leakage amount of 1 × 10 ⁻⁸ Pam ³ / sec or less required for the irradiation test body piping was satisfied.

Several thermocouples were attached to the closure plugs, and the temperature was measured to determine whether the closure stopper operation status could be confirmed, and the optimum thermocouple attachment position was tested.
By installing a thermocouple on the downstream side of the metal mesh material (filter: 40 μm) that holds the low melting point metal inside the stopper, the melting behavior of the low melting point metal inside the stopper and the molten low melting point metal The behavior of moving to close the pipe was confirmed.

  From the above results, it was confirmed that the closure behavior can be monitored by a thermocouple attached outside the closure.

It is sectional drawing which showed the structure of the closure plug of this invention. It is sectional drawing which showed the state after the closure stopper of this invention act | operates. In Example 2, the attachment position of the thermocouple with a closure plug is shown. The temperature chart of the thermocouple which confirms the operating state of the closing stopper of this invention is shown.

Explanation of symbols

1 Piping to be closed 4 Outer container 2 Low melting point metal tube 5 Heater 3 Metal mesh material 6 Thermocouple

Claims (5)

  A low-melting point metal such as tin (Sn) or indium (In) that is not affected by radiation irradiation is installed inside the pipe, and the low-melting point metal is melted by a heater provided outside the pipe, so that the pipe is fixed inside. A closure plug characterized by sealing.   A closing plug characterized by having a function of melting a low melting point metal inside the closing plug and closing a pipe by operating a heater attached outside the closing plug by remote control from outside the furnace.   A closure plug comprising a metal mesh material in order to retain a low melting point metal before melting and prevent the low melting point metal from flowing out after melting.   A closure plug characterized in that by applying gold plating to the inside of the closure plug, the adhesion of the low melting point metal is enhanced and high sealing performance is realized. A closure plug characterized in that a thermocouple is attached to the outside of the closure plug, and the state of the low-melting-point metal inside the closure plug is monitored by the signal to check the operation of the closure plug.

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