JP4409418B2 - Spacer pad forming device for trumpet pipe - Google Patents

Description

  The present invention relates to an apparatus for forming a spacer pad on a trumpet pipe in a process of manufacturing a fuel assembly for a fast reactor.

  FIG. 5 is an explanatory view showing the appearance of the fast reactor fuel assembly. As shown in the figure, the fast reactor fuel assembly 51 of the fast experimental reactor “Joyo” is filled with pellets 54 obtained by sintering a mixed oxide of plutonium and uranium in a cladding tube 53 and sealed together with helium gas. The fuel pin 52 is configured to be bundled and housed in a stainless steel sheath called a regular hexagonal trumpet tube 55. The fuel assembly 51 has an en- hancement nozzle 56 at the bottom and a neutron shield 57 under the fuel pin 52 bundle. (See Non-Patent Document 1)

  The arrangement of the fuel pins 52 in the trumpet 55 is a dense regular hexagonal lattice arrangement in order to increase the power density of the core and improve the growth performance. Only the lower end of the fuel pin 52 is fixed, and the interval between the fuel pins 52 is maintained by a wire spacer 58 wound for each fuel pin. This system has a simple structure and is characterized by being able to respond relatively flexibly to changes in the dimensions of the fuel pin 52 under neutron irradiation.

  The trumpet tube 55 is provided with a spacer pad 59 at an intermediate portion for maintaining a distance from an adjacent fuel assembly, and the surface of the spacer pad 59 is hard chrome plating for improving wear resistance. Is given.

  When a shape such as the spacer pad 59 is to be formed, generally, a molded product is a mold having a spacer pad-shaped depression (hereinafter referred to as “die”) and a mold having a spacer pad-shaped protrusion. (Hereinafter referred to as “punch”), a method of forming by applying pressure from one or both is often used. In addition, there is also a method in which a product to be molded and a die are brought into close contact, the periphery is covered with a liquid, and pressure is applied to the liquid.

Nuclear Encyclopedia ATOMICA, <large item> Reactor and research reactor under development, <medium item> fast breeder reactor, <small item> development of fast breeder reactor in Japan, <title> operation with fast experimental reactor "Joyo"・ Maintenance experience (03-01-06-02), <Renewal date> October 2003, [Search September 13, 2004] <URL: http://www-atm.jst.go.jp/ atomica / 03010602_1.html>

  However, when these spacer pad shape forming methods are applied to the trumpet tube, the location where the spacer pad is to be formed is currently about 60 cm from the tube end of the trumpet tube (the total length is about 200 cm). In addition, since the facing dimension of the trumpet tube is as small as about 8 cm, the conventional hydraulic press cannot insert the punch and the hydraulic mechanism into the trumpet tube and cannot form the spacer pad. there were.

  The present invention provides a spacer pad forming apparatus for a trumpet pipe that can easily form a spacer pad on a trumpet pipe. In particular, in a general hydraulic press method, a punch or a hydraulic mechanism is inserted into a trumpet pipe. It is an object of the present invention to provide a wrapper pad spacer pad forming apparatus that can easily form a spacer pad on a trumpet pipe, which has been difficult to implement because it cannot be performed.

A trumpet pipe spacer pad forming device according to the first aspect of the present invention is an apparatus for forming a spacer pad at a predetermined position of a regular hexagonal trumpet pipe used in a fast reactor fuel assembly.
A die frame that covers the entire circumference in the longitudinal direction of the portion including the spacer pad forming portion of the trumpet tube, and in which a spacer pad-shaped depression is formed at a predetermined position;
A punch material inserted into a position inside the trumpet tube opposite to the recess of the die frame, and a spacer pad-shaped protrusion formed on the outer wall;
A punch pressing means for pressing the punch material outward is provided.

In the trumpet pipe spacer pad forming device according to the invention described in claim 2, an inclined wall inclined with respect to the longitudinal direction of the trumpet pipe is formed on the inner wall of the punch material according to claim 1,
The punch pressing means includes an opposing inclined wall that contacts and slides against the inclined wall of the punch material, and a wedge material that presses the punch material outward by movement in the longitudinal direction inside the trumpet tube. It is what.

  According to a third aspect of the present invention, there is provided a trumpet tube spacer pad forming apparatus according to the first or second aspect, wherein the recess of the die frame and the punch material opposed thereto are among the six side walls of the trumpet tube. It arrange | positions so that two or more of these may be processed simultaneously, It is characterized by the above-mentioned.

  According to a fourth aspect of the present invention, there is provided a trumpet pipe spacer pad forming device in which two or more punch materials according to the third aspect are connected to each other by an elastic member. .

  According to a fifth aspect of the present invention, the wedge pad as the punch pressing means according to any one of the first to fourth aspects is configured so that the wedge material as the punch pressing means is hydraulically or screw tightening force inside the trumpet pipe. The longitudinal movement is performed.

  A spacer pad forming device for a trumpet pipe according to the invention described in claim 6 is a plating coating treatment or surface hardening on the surface of the die frame, punch material or wedge material according to any one of claims 1 to 5. It is characterized by having been processed.

  As described above, according to the present invention, it is possible to easily form a spacer pad on a trumpet pipe, which is difficult to realize because a general hydraulic press method cannot insert a punch or a hydraulic mechanism into the trumpet pipe. it can.

  According to the present invention, in a device for forming a spacer pad at a predetermined position of a regular hexagonal trumpet tube used in a fuel assembly for a fast reactor, the entire length of the portion including the spacer pad forming portion of the trumpet tube is formed. A die frame that covers the periphery and is formed with a spacer pad-shaped depression at a predetermined position, and is inserted into the inner position of the trumpet tube facing the depression of the die, and a spacer pad-shaped protrusion is formed on the outer wall. Punch material and punch pressing means for pressing the punch material outward. Thereby, spacer pad formation to a trumpet pipe can be performed easily.

  The punch pressing means of the present invention may be any means that presses the punch material inserted inside the trumpet tube outward. As a more preferred aspect, an inclined wall inclined with respect to the longitudinal direction of the trumpet tube is formed on the inner wall of the punch material, and an opposing inclined wall that contacts and slides on the inclined wall of the punch material is provided as punch pressing means. And a wedge material that presses the punch material outward by movement in the longitudinal direction inside the trumpet tube.

  This makes it possible to form the spacer pad on the trumpet pipe, which is difficult to realize because the punch or the hydraulic mechanism cannot be inserted into the trumpet pipe, particularly in the general hydraulic press method. Cover the entire circumference in the longitudinal direction of the part including the pad forming part with a die frame, insert the punch material into a predetermined position inside the trumpet tube facing the recess of the die frame, and insert and push in the wedge material as the punch pressing means Only by this, the spacer pad can be formed easily.

  FIG. 1 is an explanatory view showing a configuration of an embodiment of a spacer pad forming apparatus according to the present invention. As shown in the figure, the principle of the present invention is as follows. First, the recess 12 of the die frame 11 is aligned with the location where the spacer pad is to be formed, and the entire circumference of the trumpet tube 13 is restrained by the die frame 11. Thereby, the deformation of the trumpet tube 13 excluding the spacer pad due to the stress applied to the trumpet tube 13 when the spacer pad is formed can be prevented.

  Next, the punch material 14 is inserted into the inside of the trumpet tube 13, and the protrusions 15 of the punch material 14 are aligned and fixed at locations where the spacer pads are to be formed. A punch inclined wall 16 is formed on the opposite side of the protrusion 15 of the punch material 14, and a wedge inclined wall that contacts and slides on the punch inclined wall 16 of the punch material 14 is provided on the wedge material 17 as a punch pressing means. 18 is formed. Since the punch inclined wall 16 and the wedge material inclined wall 18 have the same inclination angle, by moving the wedge material 17 in the longitudinal direction of the trumpet tube 13, the respective inclined walls slide to bring the punch material 14 to the outside. Press on.

  The moved punch material 14 spreads outward while plastic deformation of the trumpet tube 13, and finally the punch material, trumpet tube, and die frame are brought into close contact with each other. Thereafter, when the movement of the wedge member 17 of the punch pressing means is restored, a spacer pad is formed with a slight spring back.

  In the present invention, the inclination angle of the inclined wall provided in the wedge material of the punch material and the punch pressing means is such that the punch material that contacts and slides on the inclined wall of the wedge material with respect to the longitudinal direction by the movement of the wedge material in the longitudinal direction. Anything that moves outward without tilting is acceptable. Therefore, the inclination angles of the mutually inclined walls are made equal (that is, the mutual angles of each other are made equal). Preferably, the inclination angle of each other is 3 to 10 °. If the inclination angle is too small, the resistance when the wedge material is pushed in becomes small, but the pushing distance must be increased, which is not efficient. If the inclination angle is too large, the distance to which the wedge material is pushed can be reduced, but the resistance at the time of pushing becomes large and the wedge material cannot be pushed.

  That is, a wedge taper that presses the punch material outward by moving in the longitudinal direction inside the trumpet tube is inserted into the trumpet tube, and an inclined wall inclined with respect to the longitudinal direction of the trumpet tube is formed. The part and the tapered part of the wedge material are brought into close contact with each other. When the wedge material is pushed in this state, the punch that is in contact with the wedge material at the tapered portion spreads outward while sliding on the tapered portion of the wedge material. When the wedge material is further pushed in, the punch spreads outward while plastic deformation of the trumpet tube, and finally the punch material, trumpet tube, and die frame come into close contact. Thereafter, when the wedge material is pulled out, a spacer pad is formed with a slight spring back.

  In the spacer pad forming apparatus of the present invention, it is easy to make a plurality of spacer pads to be formed simultaneously. That is, a plurality of spacer pads can be formed at the same time without changing the forming procedure by providing a plurality of depressions in the die frame, protrusions of the punches, and inclined walls of the wedge material. When forming a plurality of spacer pads, it is preferable to use two or three directions. That is, when the spacer pads are formed at a time, the opposing inclined walls of the wedge material may be arranged to be even. More specifically, it is preferable to form spacer pads at the same time on two opposing side walls or on three side walls rotated by 120 ° with respect to each other. This is because it is efficient to simultaneously press the other direction using the reaction force when pressing in one direction.

  Therefore, it is preferable that the recess of the die frame and the punch material opposed thereto are arranged so as to simultaneously process two or more of the six side walls of the trumpet tube. As a result, the number of steps for forming the spacer pad is reduced, and the formation time is shortened. The arrangement of the punch material and the wedge material is simplified by selecting two or more side walls that are preferably symmetrical with respect to the longitudinal axis.

  In the above-described spacer pad forming apparatus, preferably, two or more punch materials arranged are connected to each other by an elastic member. In this way, when the wedge material is pushed in and then pulled out, it returns to the state before the punch material is pushed in, and when the spacer pad is continuously formed on another side wall or when the spacer pad is formed on another trumpet tube Operation becomes easy. Also preferably, the wedge material as the punch pressing means moves in the longitudinal direction inside the trumpet tube by hydraulic pressure or screw fastening force.

  In the spacer pad forming apparatus of the present invention, preferably, the surface of the die frame, the punch material, or the wedge material is subjected to a plating coating process or a surface hardening process, thereby abutting sliding on each other, pressing on the trumpet tube, etc. It is possible to reduce the occurrence of wear and scratches due to the above.

  Even if the facing dimension of the trumpet tube or the position at which the spacer pad is formed is different, by selecting the die frame that matches the facing dimension of the trumpet pipe or changing the forming position, etc. A sensor pad can be formed.

  FIG. 2 is an explanatory view showing the front configuration of the main part of the spacer pad forming apparatus according to this embodiment. FIG. 3 is an explanatory view showing a cross-sectional configuration of a main part of the spacer pad forming apparatus of FIG. FIG. 4 is an explanatory view showing a cross-sectional configuration of the main part of the spacer pad forming apparatus of FIG. 2 after molding. In this embodiment, it is an explanatory diagram applied to a trumpet tube used in a fast experimental reactor “Joyo” core fuel assembly.

  As shown in FIG. 2, the spacer pad forming apparatus of the present embodiment is an apparatus for simultaneously forming the spacer pads 39 on the three-way tube walls of the trumpet tube 23 displaced by 120 ° from each other. For this reason, three depressions 22 are provided in the die frame 21. The depth of the recess 22 was about 2 mm in consideration of the spring back after pressing. The die frame 21 was made of carbon steel, and the surface of the recess 22 was hard chrome plated. The height of the protrusion 25 of the punch material 24 was about 2 mm in consideration of the spring back after pressing. The inclination angle of the punch inclined wall 26 formed on the opposite side of the protrusion 25 of the punch material 24 (that is, the angle between the inclined wall and the surface on which the protrusion 25 is formed) was 5 °.

  Three punch materials 24 were joined together by a spring 30. The spring 30 is for generating a force for returning the punch material 24 to the original position when the wedge material 27 is pulled out. The punch material 24 was made of carbon steel and the surface was plated with hard chrome. Further, a resin pad is provided on the punch inclined wall 26. This improves the slip of the wedge material 27 with the wedge inclined wall 28 and prevents “galling” in which the metals are fused to each other due to frictional heat caused by incomplete lubrication of the metal surface. Because.

  The inclination angle of the wedge inclined wall 28 of the wedge material 27 was set to 5 °, like the punch inclined wall 26 of the punch material 24. The wedge material 27 was made of carbon steel, and the surface was plated with hard chrome. Further, lubricating oil was applied to the surface of the wedge inclined wall 28.

  As shown in FIG. 3, using these, the portion where the spacer pad 39 of the trumpet tube 23 is to be formed is constrained by the die frame 21 over the entire circumference, and the punch material 24 is attached to the spacer pad 39 of the trumpet tube 23. The wedge material 27 is inserted into the portion to be formed and fixed, and the wedge material 27 is inserted into the trumpet tube 23 so that the surfaces of the punch inclined wall 26 of the punch material 24 and the wedge inclined wall 28 of the wedge material 27 are brought into close contact with each other. .

  As shown in FIG. 4, in this state, the wedge material 27 was pushed in from one end side of the trumpet tube 23 using a hydraulic jack, and the spacer pad 39 was formed.

  When the dimensions and appearance of the spacer pad 39 of the trumpet tube 23 thus obtained were inspected, good results were obtained. In this embodiment, the hydraulic jack is used to insert the wedge member 27, but other methods such as a method using a screw fastening force are also effective.

  In this embodiment, hard chrome plating was applied to the surface of the die frame, punch material, and wedge material to improve wear resistance. However, a coating method such as nickel plating or a surface hardening method such as carburization is also effective. .

  Formation of a spacer pad on a trumpet tube, which was difficult to achieve because a punch or a hydraulic mechanism could not be inserted into the trumpet tube in a general hydraulic press method, according to the present invention, allows a predetermined position of the trumpet tube to be formed with a die frame. The spacer pad can be easily formed simply by covering, inserting a punch at a predetermined position inside the trumpet tube, and inserting / pushing the wedge material.

  Moreover, even if the facing dimension of the trumpet tube or the position where the spacer pad is formed is different, the same procedure can be used.

It is explanatory drawing which shows the structure of one Example of the spacer pad formation apparatus of this invention. It is explanatory drawing which shows the front structure of the principal part of the spacer pad formation apparatus by a present Example. It is explanatory drawing which shows the cross-sectional structure of the principal part of the spacer pad formation apparatus of FIG. It is explanatory drawing which shows the cross-sectional structure of the principal part after shaping | molding using the spacer pad formation apparatus of FIG. It is a figure showing the external appearance of a fast reactor fuel assembly.

Explanation of symbols

11, 21 ... Dice frame,
12, 22 ...
13, 23 ... Trumpet tube,
14, 24 ... Punch material,
15, 25 ... projections,
16, 26 ... Punch inclined wall,
17, 27 ... wedge material,
18, 28 ... Wedge inclined wall,
30 ... Spring,
39 ... spacer pad,

Claims (6)

In an apparatus for forming a spacer pad at a predetermined position of a regular hexagonal trumpet pipe used in a fuel assembly for a fast reactor,
A die frame that covers the entire circumference in the longitudinal direction of the portion including the spacer pad forming portion of the trumpet tube, and in which a spacer pad-shaped depression is formed at a predetermined position;
A punch material inserted into a position inside the trumpet tube opposite to the recess of the die frame, and a spacer pad-shaped protrusion formed on the outer wall;
A trumpet tube spacer pad forming apparatus comprising punch pressing means for pressing the punch material outward. An inclined wall inclined with respect to the longitudinal direction of the trumpet tube is formed on the inner wall of the punch material,
The punch pressing means includes an opposing inclined wall that contacts and slides against the inclined wall of the punch material, and a wedge material that presses the punch material outward by movement in the longitudinal direction inside the trumpet tube. The trumpet pipe spacer pad forming apparatus according to claim 1.   The recess of the die frame and the punch material facing the die frame are disposed so as to simultaneously process two or more of the six side walls of the trumpet tube. The trumpet tube spacer pad forming apparatus as described.   The trumpet pipe spacer pad forming apparatus according to claim 3, wherein the two or more punch materials are connected to each other by an elastic member.   5. The trumpet pipe spacer pad forming apparatus according to claim 1, wherein the wedge material as the punch pressing means moves in the longitudinal direction inside the trumpet pipe by hydraulic pressure or screw fastening force. . The wrapper pad spacer pad forming apparatus according to any one of claims 1 to 5, wherein the surface of the die frame, punch material, or wedge material is subjected to a plating coating process or a surface hardening process.

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