JPH0669894U - Radiation thermometer - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] The thermocouple inserted in the vertical groove formed on the outer circumference of the rod of the radiation thermometer is fixed so that it does not float up in the shutoff chamber. [Structure] The radiation thermometer 10 includes a rod 20 formed of a cylindrical material made of a material having good thermal conductivity and good conductivity, and a shield tube 21 covers the outer circumference thereof. A recess 22 is formed at a predetermined position in the longitudinal direction of the rod 20 over the entire outer circumference to form the heat shield chamber 2
4 is forming. Vertical grooves 15, 15 ... Are formed on the outer peripheral surface of the rod 20 along the longitudinal direction, and thermocouples 30 are inserted therein. A dummy wire 50 having a diameter substantially equal to the width of the vertical groove is further inserted into the vertical groove 15 from above the inserted thermocouple 30, whereby the thermocouple 30 is pressed from above and wired. Three
0 does not float up inside the heat shield room 24.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a radiation thermometer for detecting radiation such as gamma rays emitted from a fuel pin of a nuclear reactor, and more particularly to improvement of a fixing structure of a thermocouple contained therein.

[0002]

[Prior art]

 In order to ensure the reliability and effective protection of nuclear power, it is necessary to measure the local heat output in the core fuel assembly of a nuclear reactor, for which various measuring methods and devices have already been proposed. ing. Among them, in particular, the radiation thermometer is based on heating of thermally isolated metal mass (mase) by gamma (γ) rays (about 90%) and heating by high energy neutrons (about 10%). , The heat thus generated is proportional to the output from the adjacent fuel rods.

Radiation thermometers for measuring the local heat output in such a core fuel assembly have hitherto been disclosed, for example, in Japanese Patent Publication No. 58-53759, Japanese Patent Publication No. 61-61360, and Japanese Patent Publication No. 59-16239. And so on. That is, these radiation thermometers, which are conventional techniques, are inserted and arranged in a cylindrical outer shield tube arranged in a fuel assembly in which a plurality of fuel rods are bundled, and measure local outputs at different heights. is there.

FIG. 5 and FIG. 6 show an example of the structure of the radiation thermometer according to this conventional technique. This radiation thermometer generally includes a rod 1 formed of a material having good thermal conductivity and conductivity, for example, a metal such as stainless steel, an alloy, or a conductive ceramic in a cylindrical shape, and an outer circumference thereof. And a plurality of sets of thermocouples 3 and 3 accommodated therein. This rod 1 extends over the entire height of the fuel assembly and is divided into zones for measuring the power at different heights in the fuel assembly of the reactor. That is, in the middle of the rod 1 in the longitudinal direction, a recess is formed over the outer circumference, thereby forming a plurality of heat shield chambers 4 and thermally insulating a plurality of areas from each other.

Further, a plurality of vertical grooves 5, 5, ... Are formed along the longitudinal direction on the outer periphery of the rod 1, and the temperature at a predetermined position of the rod 1 divided into a plurality of areas is measured. Therefore, thermocouples are housed in these vertical grooves 5, 5, .... That is, in order to measure the output at different heights of the fuel assembly, to measure the heating temperature in the rod 1 divided into a plurality of areas.

[0006]

[Problems to be solved by the device]

 However, in the above-mentioned conventional technique, the thermocouples 3, 3, ... Inserted in the vertical grooves 5, 5, .. In the section), the shield tube 2 covering the outer circumference does not cause the shield tube 2 to fly out of the vertical groove 5, but in the section of the shut-off chamber 4 in which the concave portion is formed (small section section), the thermoelectricity is reduced. There was a problem that the pairs 3, 3 and the like jumped out from the vertical groove 5 and floated up.

Therefore, in the present invention, in view of the above-mentioned problems of the prior art, the thermocouple inserted in the vertical groove formed on the outer circumference of the rod does not float up even in the shutoff chamber having the recess formed over the entire outer circumference. It is an object of the present invention to provide a radiation thermometer having a thermocouple fixing structure.

[0008]

[Means for Solving the Problems]

 That is, in order to achieve the above-mentioned object, the present invention comprises a cylindrical member having good heat conductivity and good conductivity, and forming a concave portion on the entire outer periphery at a predetermined position in the longitudinal direction of the heat shield chamber. And a vertical groove formed in the longitudinal direction of the outer peripheral surface of the rod, in which a thermocouple is inserted and wired in the vertical groove, the radiation thermometer being adjacent to the heat shield chamber. A radiation thermometer characterized in that a dummy wire having a diameter substantially equal to the width of the vertical groove is inserted into the vertical groove from above the inserted thermocouple to fix the thermocouple. .

[0009]

[Action]

 According to the radiation thermometer of the present invention described above, a dummy wire is further inserted from above the thermocouple which is inserted through the heat shield chamber and inserted into the longitudinal groove formed in the outer peripheral surface of the rod in the longitudinal direction. Fixed. Since this dummy wire has a straight diameter substantially equal to the width of the vertical groove, it is fixed when inserted into the vertical groove, and the thermocouple on the lower side thereof is securely fixed to the bottom of the vertical groove. Thus, at least by fixing the thermocouple wired in the vertical groove adjacent to the heat shield chamber to the bottom of the vertical groove, the thermocouple does not float up in the space of the heat shield chamber.

[0010]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 1 to 3 (FIG. 2 is a sectional view taken along the line AA of FIG. 1, and FIG. 3 is a sectional view taken along the line BB of FIG. 1), a part of a radiation thermometer 10 which is an embodiment of the present invention is particularly shown. The area where the heat-shielding room is formed is shown enlarged. In the figure, the rod 20 is formed of a material having good thermal conductivity and electrical conductivity, for example, a metal such as stainless steel, an alloy, or a conductive ceramic in a cylindrical shape. A shield tube 21 is provided on the outer periphery of the rod 20 so as to surround the rod 20. It should be noted that this rod 20 extends over the entire height of the fuel assembly of the nuclear reactor (not shown), as in the above case.

Further, the rod 20 is divided into a plurality of areas in order to measure the output at different heights in a fuel assembly of a reactor (not shown). As shown in FIG. A concave portion 22 is formed on the entire outer circumference of the heat insulating chamber 24, and thereby a heat shield chamber 24 is formed. That is, the heat shield chamber 24 has a small cross-sectional area, and therefore, a large cross-sectional area absorbs gamma (γ) rays emitted and is heated by a plurality of heating units 25, 25 in the longitudinal direction. It has the function of separating.

Further, a plurality of vertical grooves 15, 15 ... (4 in this embodiment) are formed on the outer circumference of the rod 20 along the longitudinal direction thereof, and the rod is divided into a plurality of predetermined areas. A plurality of thermocouples for measuring the heating temperature at the position are housed in these vertical grooves 15, 15. That is, a plurality of thermocouples 30, 30, ... Are provided in order to measure the output at different heights of the fuel assembly.

As shown in FIG. 4, each thermocouple 30 has conductors 32 and 33 formed of chromel in a coating tube 31 formed of, for example, Inconel, and its tip ends. A conductive wire 34 of another member forming a thermocouple made of alumel is welded to each other to form a hot junction H and a cold junction C. Further, the inside of the covering tube 31 is filled with an electric insulating material 35 such as alumina or magnesia, for electrical insulation between the conductors 32 and 33.

According to the present invention, the thermocouple 30 is inserted and wired in the outer circumference of the rod 20, the longitudinal grooves 15, 15 formed in the longitudinal direction, and further from above. A so-called dummy wire 50, which is a tubular member having a diameter substantially equal to the width of the vertical groove 15, is inserted into the device. That is, when the dummy wire 50 is pushed into the vertical groove 15, it is fixed in the vertical groove 15. By inserting the dummy wire 50 into the vertical groove 15 from above the thermocouple 30, the thermoelectric wire 30 is inserted. It becomes possible to press the pair 30 against the bottom of the vertical groove 15 and securely fix it. Therefore, even in the heat shield chamber 24 in which the rod 20 has a small cross-sectional area and forms a cylindrical space, the thermocouple 30 is reliably prevented from rising. The dummy wire 50 may be inserted over the entire longitudinal direction of the vertical groove 15, but it is particularly effective to apply the dummy wire 50 to a portion adjacent to the heat shield chamber 24 in view of its function or effect. In addition, the thermocouple fixing structure according to the present invention is economically superior because it can be carried out by a simple operation of inserting the dummy wire 50.

Although the thermocouple 30 is bent toward the center of the rod 20 in the heat shield chamber 24 in the above-mentioned embodiment, the thermocouple 30 is bent in the heat shield chamber 24 without bending. It may be wired to. In this case, it is also effective to use the dummy wire.

[0016]

[Effect of device]

 As is clear from the above detailed description of the present invention, the radiation thermometer of the present invention can securely fix the thermocouple in the vertical groove so that the thermocouple does not float up even in the heat shield chamber of the rod. It is possible to provide a thermocouple fixing structure for a radiation thermometer, which can be implemented economically and easily.

[Brief description of drawings]

FIG. 1 is a partially enlarged exploded perspective view showing a detailed structure of a radiation thermometer according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the radiation thermometer seen from the cross section taken along the line AA in FIG.

FIG. 3 is a cross-sectional view of the radiation thermometer viewed from the cross section taken along the line BB in FIG.

FIG. 4 is a partially exploded perspective view showing a detailed structure of a thermocouple arranged in the radiation thermometer.

FIG. 5 is a diagram showing an example of a radiation thermometer according to the related art.

FIG. 6 is a sectional view taken along line CC of the conventional radiation thermometer.

[Explanation of symbols]

 10 Radiation Thermometer 15 Vertical Groove 20 Rod 21 Shielding Tube 22 Recess 24 Heat Shielding Room 25 Heating Section 30 Thermocouple 50 Dummy Wire

Claims (1)

[Reference number] 0930006-02 [Claims for utility model registration] 1. A rod comprising a cylindrical member having good heat conductivity and good conductivity, wherein a recess is formed at a predetermined position in the longitudinal direction on the entire outer circumference to form a heat shield chamber, and the outer circumference of the rod. A radiation thermometer having a vertical groove formed in the longitudinal direction of the surface, wherein a thermocouple is inserted and wired in the vertical groove, wherein the insertion is performed in the vertical groove adjacent to the heat shield chamber. A radiation thermometer, wherein a dummy wire having a diameter substantially equal to the width of the vertical groove is inserted from above the thermocouple to fix the thermocouple.