JP2000111691A - Sealing method between liquid metallic sodium piping and heat reserving material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable normal preheating, to prevent the degradation of a heater, to prevent a wasteful use of electric power, to prevent reduction in insulation, and to prevent diffusion of aerosol. SOLUTION: This method seals the clearance relative to a heat reserving material in the penetrating part of a wall and a floor of liquid metallic sodium piping where an electric heater 4, a sodium leakage detector and thermometer wells 5, 6 are laid in the clearance with the heat reserving material arranged on the periphery by penetrating through the heat reserving material. At this time, the clearance between the wall, floor side piping and the heat reserving material is sealed more than a position where an electric heater 4 leader line, the thermometer wells 5, 6, a piping support device 8 and the like penetrate through the heat reserving material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing method between a liquid sodium pipe and a heat insulating material applicable to a pipe of a fast breeder reactor using liquid metal sodium as a coolant or a pipe in which a heat insulating material is arranged. .

[0002]

2. Description of the Related Art Liquid metal sodium (hereinafter, referred to as sodium) piping has an electric heater and a sodium leak detector for maintaining sodium temperature at a melting point (98 ° C.) or higher except for a penetration portion of a containment vessel. A meter is laid. FIG. 4 is a view for explaining a conventional sodium pipe, and a heat insulating material 2 is provided around a liquid metal sodium pipe 1.
A heat insulating material cover 3 is provided around the periphery. An electric heater 4, a thermometer well 5 for measuring sodium temperature, a thermometer well 6 for measuring preheating temperature, etc. are provided through these heat insulating material and heat insulating material cover, and a sodium leak detector 7 is provided between the pipe and the heat insulating material. Be placed.

[0003]

As described above, in the conventional sodium pipe, an electric heater, a sodium leak detector, a thermometer, and the like are provided between the pipe and its heat insulating material.
A gap is inevitably generated, and therefore, the following problem occurs at a portion where the liquid metal sodium pipe penetrates a wall or a floor.

[0004] Due to the pressure difference between the adjacent room, the air flowing from the gap between the lead wire of the electric heater, the thermometer well, the pipe support device, etc. and the heat insulating material flows through the gap between the pipe and the heat insulating material. In this case, the heat flows out of the gap between the thermometer well or the like and the heat insulating material, so that the amount of heat radiation on the pipe surface increases, and it becomes impossible to preheat to the required temperature. This point will be described with reference to FIG. 5. It is assumed that the sodium pipe 1 is connected to the wall 9 by the pipe support device 8. In this connection, for example, the pipe is sandwiched between two upper and lower clamps, both sides of the clamp are fixed with bolts and nuts, and the clamp is connected to a pipe support device. Now, assuming that the pressure on the left side of the wall 9 is low and that on the right side is high, air flows in from the mounting portion of the electric heater 4, the thermometer wells 5, 6 and the pipe support device 8 in the left side room due to the pressure difference, and the heat insulator As shown by the arrow, it flows into the room on the right side through the space between the water and the sodium pipe, and flows out of the room from the mounting portion of the electric heater, the thermometer well, and the pipe support device. For this reason, the amount of heat radiation on the pipe surface increases, and it is not possible to preheat to a required temperature. In a vertical pipe, even if there is no pressure difference between adjacent rooms, natural convection of air occurs due to the chimney effect, causing a temperature difference above and below the pipe, and it is not possible to preheat to the required temperature below the pipe There is. When the electric heater and the current-carrying type leak detector absorb moisture in the flowing air, the insulation resistance is reduced. Should sodium flow out, the leaked sodium and the aerosol generated by the reaction of sodium with air would be diffused along the same path as otherwise.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a liquid metal capable of normal preheating, preventing deterioration of a heater and preventing wasting of electric power, preventing deterioration of insulation, and preventing diffusion of aerosol. An object of the present invention is to provide a method for sealing a sodium pipe and a heat insulating material.

[0006]

According to the present invention, there is provided a liquid metal sodium pipe having an electric heater, a sodium leak detector, and a thermometer well laid through a heat insulating material in a gap with a heat insulating material provided in the periphery. A method for sealing a gap with a heat insulating material in a penetrating portion of a wall, a floor, etc.
It is characterized in that a gap between the pipe and the heat insulator at a position closer to the wall or floor than the position where the thermometer well, the pipe support device and the like penetrate the heat insulator is sealed. In the present invention, the seal may include a heat-insulating or heat-resistant sealing material formed into the same or a larger dimension as a gap between the pipe and the heat insulating material, attached to the airtight band, and provided between the pipe and the steel sheet on the inner surface of the heat insulating material. It is characterized by being attached to. Further, the present invention is characterized in that a cutout for laying an electric heater is provided in the sealing material. Further, the present invention is characterized in that the steel sheet is fastened with a seat band from outside the steel sheet at the sealed portion.

[0007]

Embodiments of the present invention will be described below. FIG. 1 is a diagram showing an attached state of a sodium pipe of the present invention, and FIG. 2 is a diagram illustrating a heat insulating material and an airtight band.
A method of sealing all the gaps between the inflow and outflow of the electric heater, the thermometer well, the piping support device and the heat insulating material, which are the inflow and outflow portions of air, is also considered. Inflow and outflow from the upstream side,
The effect is small. For this reason, it is necessary to seal all of these gaps, and the number thereof is enormous, which is not practical. Therefore, in the present invention, the problem is solved with a minimum number of constructions.

[0010] As shown in FIG. 1, for each part where the pipe penetrates the wall or the floor, the pipe on the wall or floor side with respect to the position where the electric heater lead wire, the thermometer well, the pipe support device, etc. penetrates the heat insulating material. Seal one of the gaps in the insulation. In FIG. 1, when the pipe penetrates the wall 9, the airtight band 10 is attached to the side closer to the wall 9 than the mounting position of the electric heater 4, the thermometer wells 5 and 6, and the pipe support device 8.

The state of attachment of the band 10 will be described with reference to FIG. 2. A heat insulating material or a heat-resistant sealing material formed to have the same size as or slightly larger than the gap between the sodium pipe 1 and the heat insulating material is attached to the band 10. It is attached to the inside of the steel sheet 12 by sticking. It should be noted that only the electric heater 4 is laid on the penetration part of the wall or floor,
A notch 11a corresponding to the diameter of the electric heater is provided in the heat insulating material 11 formed as necessary. Further airtight band 1
The steel sheet 12 is clamped from the outside with the seat band 13 in order to eliminate the gap between the outside of the steel sheet 0 and the inside of the steel sheet 12 and to additionally tighten the airtight band. One or more leak detectors are installed between the airtight bands. By providing such a molded heat insulating material, it is possible to prevent air that has flowed between the pipe and the heat insulating material from flowing through these gaps and flowing out of an adjacent room.

[0010] The installation position of such an airtight band is not related to the upstream and downstream of the pipe, but it is preferable to install the airtight band so that sodium leakage can be detected more quickly. When the airtight band is provided, the leaked sodium is prevented from flowing through the gap between the pipe and the heat insulating material and arriving at the leak detector, so that a new sodium leak detector needs to be added. As shown in FIG.
Normally, the pipes are installed with a slope to improve the drainage of sodium. When the leak detector 7 is installed on the downstream side as shown in the figure and the airtight band 10 is installed near the wall 9, even if there is a leak on the upstream side of the airtight band 10, sodium is detected in the leak detector 7. Therefore, it is preferable to newly install a leak detector 7 'on the upstream side of the airtight band, since the arrival is hindered.

[0011]

As described above, according to the present invention, the following effects can be obtained. Since the amount of heat radiation on the surface of the sodium pipe can be reduced, it can be preheated to a required temperature. Due to the decrease in the amount of heat radiation, the time for energizing the electric heater is shortened, and deterioration of the electric heater and waste of electric power can be prevented. It is possible to prevent a decrease in insulation resistance due to moisture absorption of the electric heater and the energized leak detector. Should sodium leak, it is possible to prevent the leaked sodium and the aerosol generated by the reaction between sodium and air from diffusing out of the leaked room. In addition, since the leak area (volume) can be limited, the time required for leak detection can be shortened, and the leak area (place) can be reduced.
Can be easily specified.

[Brief description of the drawings]

FIG. 1 is a diagram showing an attached state of a sodium pipe of the present invention.

FIG. 2 is a diagram illustrating a heat insulating material and an airtight band.

FIG. 3 is a diagram illustrating a positional relationship between a seal mounting position and a leak detector.

FIG. 4 is a diagram illustrating a conventional sodium pipe.

FIG. 5 is a diagram illustrating the inflow and outflow of air through a gap between a pipe and a heat insulating material.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Liquid metal sodium piping, 2 ... Heat insulation material, 3 ... Heat insulation material cover, 4 ... Electric heater, 5 ... Sodium temperature measurement thermometer well, 6 ... Preheating temperature measurement temperature well, 7,
7 ': leak detector, 8: piping support device, 9: wall, 10 ...
Airtight band, 11: molded heat insulating material, 11a: notch, 12
... Steel sheet, 13 ... Seat band.

Claims (4)

[Claims] An electric heater, a sodium leak detector, and a thermometer well are provided in a space between the heat insulating material and a surrounding portion such as a wall or a floor of a liquid metal sodium pipe laid through the heat insulating material. A method of sealing the gap between the heat insulating material and the space between the pipe and the heat insulating material at a position closer to the wall or floor than the position where the electric heater lead wire, thermometer well, pipe support device, etc. penetrates the heat insulating material. A sealing method between a liquid metal sodium pipe and a heat insulating material. 2. The method according to claim 1, wherein the seal is formed by attaching a heat-insulating or heat-resistant sealing material having the same size or a larger size as a gap between the pipe and the heat-insulating material to an airtight band. A sealing method between a liquid metal sodium pipe and a heat insulating material, wherein the method is mounted between steel sheets on the inner surface of the heat insulating material. 3. The sealing method according to claim 2, wherein the sealing member is provided with a cutout for laying an electric heater. 4. The method according to claim 2, wherein
A method of sealing between a liquid metal sodium pipe and a heat insulating material, wherein a sheet band is tightened from outside of a steel sheet at a sealed portion.