Guide sleeve and how to remove the guide sleeve

Abstract

Easily removable. [Solution] A guide sleeve inserted into the threaded portion of the reactor vessel body, comprising a cylindrical portion including a first member and a second member which are arc-shaped, with a male threaded portion formed on a part of the outer circumference and a female threaded portion formed on a part of the inner circumference, and a dividing portion which connects the end of the arc of the first member and the end of the arc of the second member, making the first member and the second member annular in shape.

Description

Technical Field

[0001] The present disclosure relates to a guide sleeve and a method for removing the guide sleeve.

Background Art

[0002] A reactor vessel opens and closes a reactor vessel head during inspection. Patent Document 1 discloses a guide stud that is used when opening and closing a reactor vessel head and has a screw protection cylinder connected to the tip end portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The screw protection cylinder (guide sleeve) is inserted into the female screw that fastens the reactor vessel head of the reactor vessel. The guide sleeve may be fixed due to rust or foreign matter, etc. If it is fixed, it may be difficult to remove the guide sleeve from the female screw.

[0005] The present disclosure solves the above-described problems and aims to provide a guide sleeve that can be easily removed and a method for removing the guide sleeve.

Means for Solving the Problems

[0006] [[ID=4B]] In order to solve the above-described problems and achieve the object, the guide sleeve according to the present disclosure is a guide sleeve that is inserted into a screw portion of a reactor vessel body, and includes a first member and a second member having an arc shape, and a cylindrical portion having a male screw portion formed on a part of an outer peripheral surface and a female screw portion formed on a part of an inner peripheral surface, and a dividing portion that connects an end portion of the arc of the first member and an end portion of the arc of the second member and forms the first member and the second member into an annular shape.

[0007] To solve the above-mentioned problems and achieve the objective, the removal method according to the present disclosure is a method for removing a guide sleeve inserted into a threaded portion of a reactor vessel body, wherein the guide sleeve includes a first member and a second member which are arc-shaped, a cylindrical portion which has a male threaded portion formed on a part of its outer circumferential surface and a female threaded portion formed on a part of its inner circumferential surface, and a dividing portion which connects the end of the arc of the first member and the end of the arc of the second member, making the first member and the second member annular in shape, and the method includes the steps of operating the dividing portion to separate the first member and the second member, and removing the separated first member and the second member from the threaded hole. [Effects of the Invention]

[0008] According to this disclosure, it can be easily removed. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a cross-sectional view of a pressurized water reactor. [Figure 2] Figure 2 is a perspective view of the guide sleeve according to the first embodiment. [Figure 3] Figure 3 is a schematic diagram showing an example of a jig. [Figure 4] Figure 4 is a schematic side view illustrating the method of installing the guide sleeve. [Figure 5] Figure 5 is a schematic side view illustrating the method of installing the guide sleeve. [Figure 6] Figure 6 is a schematic side view illustrating the method of installing the guide sleeve. [Figure 7] Figure 7 is a schematic top view illustrating how to remove the guide sleeve. [Figure 8] Figure 8 is a schematic top view illustrating how to remove the guide sleeve. [Figure 9] Figure 9 is a perspective view of the guide sleeve according to the second embodiment. [Figure 10]FIG. 10 is a perspective view of the guide sleeve according to the second embodiment with the connecting fitting removed. [Figure 11] FIG. 11 is a perspective view of the connecting fitting. [Figure 12] FIG. 12 is a schematic side view for explaining the insertion method of the connecting fitting. [Figure 13] FIG. 13 is a schematic side view for explaining the removal method of the guide sleeve according to the second embodiment.

MODE FOR CARRYING OUT THE INVENTION

[0010] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited by this embodiment, and when there are a plurality of embodiments, those configured by combining each embodiment are also included.

[0011] <First Embodiment> <Pressurized Water Reactor> FIG. 1 is a cross-sectional view showing a pressurized water reactor.

[0012] Although not shown, a nuclear power plant has a reactor and a steam generator disposed in a reactor containment vessel, and a steam turbine power generation facility. The reactor of the present embodiment is a pressurized water reactor (PWR: Pressurized Water Reactor). However, the reactor may be any reactor such as a boiling water reactor (BWR: Boiling Water Reactor) or a fast breeder reactor (FBR: Fast Breeder Reactor).

[0013] As shown in FIG. 1, in the pressurized water reactor 10, the reactor vessel 11 is composed of a reactor vessel main body 12 and a reactor vessel head 13 attached to the upper part thereof so that in-vessel structures can be inserted therein. The reactor vessel head 13 is fixed to the reactor vessel main body 12 by a plurality of stud bolts 14 and nuts  15 so as to be openable and closable.

[0014] The reactor vessel main body 12 has a cylindrical shape with an open upper part and a closed lower part having a hemispherical shape. An inlet nozzle 16 for supplying light water as the primary coolant and an outlet nozzle 17 for discharging light water are formed in the upper part. The reactor vessel main body 12 has a core shroud 18 disposed therein, and the upper part is supported by the inner wall surface of the reactor vessel main body 12. The upper core support plate 19 is disposed inside the reactor vessel main body 12, and the upper part is supported by the upper part of the core shroud 18. The upper core plate 20 is suspended and supported by the upper core support plate 19 by a plurality of core support rods 21.

[0015] The core shroud 18 has a lower core support plate 22 supported therebelow. The lower core support plate 22 is positioned and supported by a positioning member 23 on the inner wall surface of the reactor vessel main body 12 at its outer peripheral portion. The core shroud 18 has a lower core plate 24 supported therebelow. The core 25 is configured by arranging a large number of fuel assemblies 26, and a large number of control rods 27 are arranged therein. These control rods 27 can be inserted into the fuel assemblies 26. The upper core support plate 19 has a large number of control rod cluster guide tubes 28 fixed thereto, and the control rods 27 can be inserted therethrough. The reactor vessel head 13 has a hemispherical shape, and a control rod drive device 29 is disposed therein. A plurality of control rod cluster drive shafts 30 are inserted into the control rod cluster guide tubes 28, and the control rods 27 are connected to the lower ends thereof. The control rod drive device 29 controls the reactor output by inserting and removing each control rod 27 with respect to the core 25.

[0016] As described above, the reactor vessel head 13 is arranged to close the opening of the reactor vessel main body 12 and is fastened to the reactor vessel main body 12 by a plurality of stud bolts 14 and a plurality of nuts 15. The reactor vessel head 13 has a plurality of through holes 13a formed therein, and the plurality of stud bolts 14 are respectively inserted into the through holes 13a and fastened to the reactor vessel main body 12 by the plurality of nuts 15. The male thread portion 14a of the stud bolt 14 is screwed into a stud hole 12a which is a thread portion (female thread) of the reactor vessel main body 12.

[0017] <Guide sleeve> FIG. 2 is a perspective view of a guide sleeve according to the first embodiment.

[0018] The guide sleeve 40 according to this embodiment is a metal protective member. The guide sleeve 40 is used when opening and closing the reactor vessel lid 13 during inspection of the reactor vessel 11. During inspection, when opening and closing the reactor vessel lid 13, a guide stud 98, which is a pin that adjusts the position of the reactor vessel lid 13, is inserted into the stud hole 12a. The guide sleeve 40 is inserted into the stud hole 12a before the guide stud 98 is inserted into the stud hole 12a, protecting the stud hole 12a. The length of the guide sleeve 40 is such that it does not come into contact with the reactor vessel lid 13. For example, the length of the guide sleeve 40 is the same as the length (depth) of the stud hole 12a or slightly shorter than the length (depth) of the stud hole 12a.

[0019] As shown in Figure 2, the guide sleeve 40 has a cylindrical portion 42 and a divided portion 78.

[0020] The cylindrical portion 42 includes a first member 44 and a second member 64. In this embodiment, the first member 44 and the second member 64 have a symmetrical shape with the line dividing the cylindrical portion 42 into semicircles as the line of symmetry. The first member 44 and the second member 64 are each arc-shaped. The first member 44 has end portions 48 at both ends in the circumferential direction of the arc. The second member 64 has end portions 68 at both ends in the circumferential direction of the arc. In this embodiment, both ends of the arc shape are flat, but they may be uneven. An end portion 48a is formed at one end in the circumferential direction of the first member 44, and an end portion 48b is formed at the other end in the circumferential direction. An end portion 68a is formed at one end in the circumferential direction of the second member 64, and an end portion 68b is formed at the other end.

[0021] The first member 44 and the second member 64 are arranged with their ends 48a and 68a facing each other, and their ends 48b and 68b facing each other, with a gap G between them. The first member 44 and the second member 64 are connected at ends 48a and 68a, and at ends 48b and 68b, respectively, via dividing portions 78. The inner circumferential surfaces of the arcs of the first member 44 and the second member 64 face each other, forming a space S inside the opposing arcs. Hereafter, the first member 44 and the second member 64 will be collectively referred to as the cylindrical portion 42 as appropriate. Also, ends 48a and 48b will be collectively referred to as end 48. Furthermore, ends 68a and 68 will be collectively referred to as end 68.

[0022] (First component) The first member 44 has an engaging portion 52, a male threaded portion 54, and a female threaded portion 56.

[0023] The engaging portion 52 is a groove provided in the center of the end face 44c of the upper part 44a of the first member 44. The jig 90, which will be described later, engages with the engaging portion 52. The engaging portion 52 has an engaging edge 52a, an engaging hole 52b, and a hook portion 52c.

[0024] The engaging edge 52a opens from the end face 44c at the upper part 44a of the first member 44 and is divided into two parts along the circumferential direction. The engaging edge 52a restricts the rotation of the jig 90 with its circumferential end. The engaging hole 52b is into which the jig 90 engages. The engaging hole 52b is formed at both ends of the engaging edge 52a. Engaging holes 52ba and 52bb are formed at both ends of the engaging edge 52a, respectively. Engaging holes 52ba and 52bb are formed facing the end face 44c. The jig 90 engages with the engaging holes 52ba and 52bb. The hook portion 52c acts as a wall of the opening from the end face 44c and protrudes from the engaging edge 52a. The hook portion 52c maintains the engaged state of the jig 90 when the jig 90 is inserted along the engaging edge 52a and engages with the engaging hole 52b.

[0025] The male threaded portion 54 is formed by cutting threads into a part of the outer circumferential surface of the first member 44. The male threaded portion 54 is formed between the upper part 44a and the lower part 44b of the first member 44. The male threaded portion 54 is formed on the outer circumferential surface up to the edge of the end portion 48. In other words, the male threaded portion 54 is not formed at the end portions 48a and 48b. The male threaded portion 54 is screwed into the stud hole 12a of the reactor vessel body 12.

[0026] The female thread portion 56 is formed on a part of the inner circumferential surface of the first member 44. The female thread portion 56 is formed on the inner circumferential surface along the circumferential direction of the first member 44, between the center and the lower part 44b. The female thread portion 56 is formed on the inner circumferential surface up to the edge of the end portion 48. In other words, the female thread portion 56 is not formed at the end portion 48a and the end portion 48b. The male thread of the guide stud 98 is screwed into the female thread portion 56.

[0027] (Second component) The second member 64 has an engaging portion 72, a male threaded portion 74, and a female threaded portion 76.

[0028] The engaging portion 72 is a groove provided in the center of the end face 64c of the upper part 64a of the second member 64. The jig 90, which will be described later, engages with the engaging portion 72. The engaging portion 72 has an engaging edge 72a, an engaging hole 72b, and a hook portion 72c.

[0029] The engaging edge 72a opens from the end face 64c at the upper part 64a of the second member 64 and is divided into two parts along the circumferential direction. The engaging edge 72a restricts the rotation of the jig 90 with its circumferential end. The engaging hole 72b is into which the jig 90 engages. The engaging hole 72b is formed at both ends of the engaging edge 72a. Engaging holes 72ba and 72bb are formed at both ends of the engaging edge 72a, respectively. Engaging holes 72ba and 72bb are formed facing the end face 64c. The jig 90 engages with the engaging holes 72ba and 72bb. The hook portion 72c acts as a wall of the opening from the end face 64c of the second member 64 and protrudes from the engaging edge 72a. The hook portion 72c maintains the engaged state of the jig 90 when the jig 90 is inserted along the engaging edge 72a and engages with the engaging hole 72b.

[0030] The male threaded portion 74 is formed by cutting threads into a part of the outer circumferential surface of the second member 64. The male threaded portion 74 is formed between the upper part 64a and the lower part 64b of the second member 64. The male threaded portion 74 is formed on the outer circumferential surface up to the edge of the end portion 68. In other words, the male threaded portion 74 is not formed at the end portions 68a and 68b. The male threaded portion 74 is screwed into the stud hole 12a of the reactor vessel body 12.

[0031] The female thread portion 76 is formed on a part of the inner circumferential surface of the second member 64. The female thread portion 76 is formed on the inner circumferential surface along the circumferential direction of the second member 64, between the center and the lower part 64b. The female thread portion 76 is formed on the inner circumferential surface up to the edge of the end portion 68. In other words, the female thread portion 56 is not formed at the end portion 68a and the end portion 68b. The male thread of the guide stud 98 is screwed into it.

[0032] (divided part) The dividing section 78 is a structure that connects the first member 44 and the second member 64 to form a cylindrical shape. In this embodiment, the dividing section 78 is positioned at two locations where the arc-shaped first member 44 and the arc-shaped second member 64 face each other. In other words, the dividing section 78 is positioned at two locations 180 degrees apart on the cylindrical guide sleeve 40. The guide sleeve 40 can separate the first member 44 and the second member 64 by performing a predetermined operation on the dividing section 78. In this embodiment, the dividing section 78 is four plate-shaped thin-walled sections 80.

[0033] The thin-walled portion 80 is positioned in the gap G of the cylindrical portion 42 and does not have male threaded portions 54 and 74, or female threaded portions 56 and 76. The thin-walled portion 80 includes a first thin-walled portion 80a and a second thin-walled portion 80b.

[0034] The first thin-walled portion 80a is a plate member with a thickness thinner than the thickness of the cylindrical portion 42 and is easy to cut. The first thin-walled portion 80a is a plate member with a thickness thinner than the width between the end 48 and the end 68 and is easy to cut. The first thin-walled portion 80a is positioned in the gap G between the end 48a and the end 68a. The first thin-walled portion 80a is positioned near the upper parts 44a and 64a at the end 48a and the end 68a, connecting the first member 44 and the second member 64. The first thin-walled portion 80a is also positioned in the gap G between the end 48b and the end 68b. The first thin-walled portion 80a is positioned near the upper parts 44a and 64a at the end 48b and the end 68b, connecting the first member 44 and the second member 64. In this embodiment, two first thin-walled portions 80a are positioned facing each other in the circumferential direction, connecting the first member 44 and the second member 64. Furthermore, when the first thin-walled portion 80a is cut, the first member 44 and the second member 64 are no longer connected.

[0035] The second thin-walled portion 80b is a plate member with a thickness thinner than the thickness of the cylindrical portion 42 and is easy to cut. It is a plate member with a thickness thinner than the width between the ends 48 and 68 and is easy to cut. The second thin-walled portion 80b is positioned in the gap G between the ends 48a and 68a. The second thin-walled portion 80b is positioned near the lower parts 44b and 64b at the ends 48a and 68a, connecting the first member 44 and the second member 64. The second thin-walled portion 80b is also positioned in the gap G between the ends 48b and 68b. The second thin-walled portion 80b is fixed to the respective ends 48b and 68b of the first member 44 and the second member 64. The second thin-walled portion 80b is positioned near the lower parts 44b and 64b at the ends 48b and 68b, connecting the first member 44 and the second member 64. In this embodiment, two second thin-walled portions 80b are arranged facing each other in the circumferential direction, connecting the first member 44 and the second member 64. Alternatively, the second thin-walled portions 80b can be cut, resulting in a state where the first member 44 and the second member 64 are not connected.

[0036] The number of circumferential divisions in the cylindrical portion of the guide sleeve 40 is not limited to two. Furthermore, the divisions 70 are provided at the connection points of the cylindrical portion 42. Therefore, if the cylindrical portion of the guide sleeve 40 is divided into three circumferential sections, the divisions 70 will be provided at three locations. Note that by dividing the guide sleeve 40 into two circumferential sections as in this embodiment, workability can be improved.

[0037] <Jig> Figure 3 is a schematic diagram showing an example of a jig.

[0038] The jig 90 is a tool used to attach and detach the guide sleeve 40 to the stud holes 12a of the reactor vessel body 12. The jig 90 has a handle 92, a support column 94, and an operating rod 96.

[0039] The handle 92 rotates the jig 90 when the handle 92 is turned. The handle 92 may have any shape.

[0040] The support column 94 is positioned between the handle 92 and the operating rod 96 and is a member that supports them.

[0041] The operating rod 96 is a rod-shaped member that engages with the guide sleeve 40. The operating rod 96 is provided protruding from the support column 94. In this embodiment, two operating rods 96 are provided protruding diagonally from the support column 94. The operating rod 96 rotates in conjunction with the rotation of the handle 92. The operating rod 96 engages with the engaging portion 52 and the engaging portion 72 of the cylindrical portion 42, respectively. The operating rod 96 is inserted into the engaging edge 52a of the engaging portion 52 and the engaging edge 72a of the engaging portion 72 of the cylindrical portion 42, and engages with the engaging hole 52b and the engaging hole 72b. The engaged state of each operating rod 96 engaged with the engaging portion 52 and the engaging portion 72 is maintained by the hook portion 52c and the hook portion 72c.

[0042] <How to remove> Next, the method for removing the guide sleeve 40 will be explained along with the method for installing the guide sleeve 40. Figures 4 to 6 are schematic side views illustrating the method for installing the guide sleeve. Figures 7 and 8 are schematic top views illustrating the method for removing the guide sleeve.

[0043] As shown in Figure 4, the worker inserts the guide sleeve 40 into the stud holes 12a of the reactor vessel body 12. The worker inserts the guide sleeve 40 into, for example, three stud holes 12a. Here, the installation of the guide sleeve 40 is performed with the reactor vessel lid 13 in place on the reactor vessel body 12. The installation of the guide sleeve 40 is performed, for example, after removing the existing stud bolts 14 in order to remove the reactor vessel lid 13 of the reactor vessel during inspection, fuel loading, etc. The guide sleeve 40 can also be inserted into stud holes 12a where no existing stud bolts 14 have been inserted.

[0044] Specifically, the worker inserts the jig 90 into the guide sleeve 40. The worker inserts the operating rod 96, aligning it with the engaging portions 52 and 72 of the cylindrical portion 42. Then, the worker rotates the jig 90 in the direction of arrow A using the handle 92, thereby rotating the operating rod 96 along the engaging edges 52a and 72a. Once the rotation of the operating rod 96 is restricted at the ends of the engaging edges 52a and 72a, the worker lifts the jig 90 to engage the operating rod 96 with one of the engaging holes 52ba and 72ba of the guide sleeve 40. The worker aligns the guide sleeve 40, into which the jig 90 has been inserted, with the stud hole 12a and rotates the jig 90 in the direction of arrow A. As a result, the guide sleeve 40 moves in the direction of arrow B (downward), and the male threaded portions 54 and 74 of the guide sleeve 40 are screwed into the stud hole 12a of the reactor vessel body 12.

[0045] As shown in Figure 5, the worker inserts the guide stud 98 into the guide sleeve 40. Then, if necessary, the reactor vessel lid 13 is lifted by a conveying device and separated from the reactor vessel body 12. When separating the reactor vessel lid 13 from the reactor vessel body 12, the reactor pit is filled with water. After the work on the inside of the reactor vessel body 12 is completed, the reactor vessel lid 13 is installed on the reactor vessel body 12. When installing the reactor vessel lid 13 on the reactor vessel body 12, the guide stud 98 is used to position the reactor vessel lid 13.

[0046] The worker inserts the guide stud 98 into the space S of the guide sleeve 40 and screws the male threaded portion (not shown) of the guide stud 98 into the female threaded portions 56 and 76 provided on the inner circumferential surface of the cylindrical portion 42. The worker operates a crane (not shown) that moves the reactor vessel lid 13 and places the reactor vessel lid 13 on the reactor vessel body 12 by aligning it with the guide stud 98 and passing it through the through hole 13a of the reactor vessel lid 13. The worker operates the crane to position the reactor vessel lid 13 so that the position of the through hole 13a of the reactor vessel lid 13 coincides with the position of the stud hole 12a of the reactor vessel body 12.

[0047] As shown in Figure 6, the worker removes the guide stud 98 from the guide sleeve 40.

[0048] Then, the worker removes the guide sleeve 40 from the stud hole 12a. Although not shown in the diagram, the worker rotates the jig 90 in the opposite direction to arrow A to remove the guide sleeve 40 from the stud hole 12a of the reactor vessel body 12. Similar to when inserting the guide sleeve 40, the worker engages the operating rod 96 with the engaging parts 52 and 72 of the cylindrical part 42, rotates the jig 90 in the opposite direction to arrow A, and lifts the jig 90 to engage the other engaging hole 52bb and engaging hole 72bb. The worker then rotates the jig 90, which is engaged with the engaging parts 52 and 72, in the opposite direction to arrow A to remove the guide sleeve 40 from the stud hole 12a.

[0049] In this case, if the guide sleeve 40 becomes stuck to the stud hole 12a of the reactor vessel body 12 due to rust or contamination, it may become difficult to remove it from the stud hole 12a of the reactor vessel body 12 using the jig 90.

[0050] If the guide sleeve 40 becomes stuck and difficult to remove from the stud hole 12a of the reactor vessel body 12, as shown in Figure 7, the worker removes the guide sleeve 40 by separating it at the divided section 78. Specifically, the worker removes the guide sleeve 40 by cutting the thin-walled section 80. The worker cuts the thin-walled section 80 with a cutting tool (not shown). The worker cuts both the first thin-walled section 80a and the second thin-walled section 80b with the cutting tool. After cutting, a gap 80c is formed in the thin-walled section 80. This separates the first member 44 and the second member 64. As shown in Figure 8, the worker shifts the first member 44 in the direction of arrow C (towards the center) of the guide sleeve 40. With the first member 44 shifted and the gap 80c narrowed, the worker pulls up the first member 44 to remove it from the stud hole 12a. The worker removes the second member 64 from the stud hole 12a in the same manner as the first member 44. A cutting tool such as a grinder can be used here. Furthermore, cutting the thin-walled portion 80 is not limited to cutting, as long as it does not damage the stud hole 12a of the reactor vessel body 12.

[0051] The worker secures the reactor vessel lid 13 with stud bolts 14. The stud bolts 14 are inserted into the through holes 13a of the reactor vessel lid 13, and the reactor vessel lid 13 is fastened to the reactor vessel body 12 (see Figure 1).

[0052] <Effects of the First Embodiment> The guide sleeve 40 according to the first embodiment has a cylindrical portion 42 and a divided portion 78. The cylindrical portion 42 includes a first member 44 and a second member 64, which are arranged with a gap G between them. The divided portion 78 is a thin-walled portion 80, which is placed in the gap G and connects the first member and the second member. The thin-walled portion 80 does not have a threaded portion. As a result, by cutting the thin-walled portion 80, the guide sleeve 40 can be separated from the cylindrical portion 42 into the first member 44 and the second member 64 while minimizing damage to the stud hole 12a. Therefore, the guide sleeve 40 can be easily removed from the stud hole 12a.

[0053] <Second Embodiment> <Guide Sleeve> Next, the guide sleeve 40A of the second embodiment will be described. The guide sleeve 40 according to the second embodiment differs from the guide sleeve 40 of the first embodiment in that the first member 44 and the second member 64 are connected by a connecting fitting 120. Components similar to those in the first embodiment are denoted by the same reference numerals and their description is omitted.

[0054] Figure 9 is a perspective view of the guide sleeve according to the second embodiment. Figure 10 is a perspective view of the guide sleeve according to the second embodiment with the connecting fitting removed.

[0055] As shown in Figures 9 and 10, the guide sleeve 40A has a cylindrical portion 42 and a divided portion 78A.

[0056] The cylindrical portion 42 includes a first member 44 and a second member 64. The first member 44 and the second member 64 have symmetrical shapes with respect to a line dividing the cylindrical portion 42 into semicircles. The first member 44 and the second member 64 are each arc-shaped. The first member 44 has end portions 48 at both ends in the circumferential direction of the arc. The second member 64 has end portions 68 at both ends in the circumferential direction of the arc. In this embodiment, the end portions 68 at both ends of the arc shape are flat surfaces, but the flat surfaces may have portions that are uneven relative to the other member. One end of the first member 44 has an end portion 48a, and the other end has an end portion 48b. One end of the second member 64 has an end portion 68a, and the other end has an end portion 68b.

[0057] The first member 44 and the second member 64 are positioned with their ends 48a and 68a facing each other, and their ends 48b and 68b facing each other, with a gap G between them. The inner surfaces of the arcs of the first member 44 and the second member 64 face each other, forming a space S inside the opposing arcs. The first member 44 and the second member 64 are separated by a dividing portion 78A.

[0058] (First component) The first member 44 has an engaging portion 52, a male threaded portion 54, and a female threaded portion 56. The engaging portion 52 is the same as in the first embodiment, so its description is omitted.

[0059] The male threaded portion 54 is formed by cutting threads into a part of the outer circumferential surface of the first member 44. The male threaded portion 54 is formed between the upper part 44a and the lower part 44b of the first member 44. On the outer circumferential surface, the male threaded portion 54 is formed up to the edge of the outer surface 102 of the divided portion 78A, which will be described later. In other words, the male threaded portion 54 is not formed on the outer surface 102. The male threaded portion 54 is screwed into the stud hole 12a of the reactor vessel body 12.

[0060] The female thread portion 56 is formed on a part of the inner circumferential surface of the first member 44. The female thread portion 56 is formed on the inner circumferential surface of the first member 44 along the circumferential direction, between the center and the lower part 44b. The female thread portion 56 is formed on the inner circumferential surface up to the edge of the protruding surface 78Aa of the divided portion 78A. In other words, the female thread portion 56 is not formed on the protruding surface 78Aa of the divided portion 78A. The male thread of the guide stud 98 is screwed into the female thread portion 56.

[0061] (Second component) The second member 64 has an engaging portion 72, a male threaded portion 74, and a female threaded portion 76. The engaging portion 72 is the same as in the first embodiment, so its description is omitted.

[0062] The male threaded portion 74 is formed by cutting threads into a part of the outer circumferential surface of the second member 64. The male threaded portion 74 is formed between the upper part 64a and the lower part 64b of the second member 64. On the outer circumferential surface, the male threaded portion 74 is formed up to the edge of the outer surface 102 of the divided portion 78A. In other words, the male threaded portion 74 is not formed on the outer surface 102. The male threaded portion 74 is screwed into the stud hole 12a of the reactor vessel body 12.

[0063] The female thread portion 76 is formed on a part of the inner circumferential surface of the second member 64. The female thread portion 76 is formed on the inner circumferential surface of the second member 64 along the circumferential direction, between the center and the lower part 64b. The female thread portion 76 is formed on the inner circumferential surface up to the edge of the protruding surface 78Aa of the divided portion 78A. In other words, the female thread portion 56 is not formed in shape on the protruding surface 78Aa of the divided portion 78A. The male thread of the guide stud 98 is screwed into it.

[0064] Furthermore, the connecting fitting 120 is inserted into the guide sleeve 40A. The cylindrical portion 42 is inserted into the connecting fitting 120 in the divided portion 78A, and the first member 44 and the second member 64 are connected via the connecting fitting.

[0065] (divided part) The divided portion 78A is positioned in the gap G between the end 48 of the first member 44 and the end 68 of the second member 64. The divided portion 78A has a connecting fitting 120 that connects the first member 44 and the second member 64. The divided portion 78A allows the first member 44 and the second member 64 to be separated by removing the connecting fitting 120 from the first member 44 and the second member 64. The divided portion 78A connects the first member 44 and the second member 64 via the connecting fitting 120 by attaching the connecting fitting 120 to the first member 44 and the second member 64. The divided portion 78A also includes circumferential end peripheral structures of the first member 44 and the second member 64 that connect to the connecting fitting 120. The divided portion 78A comprises an outer surface 102, a hole 108, and a groove 110.

[0066] The outer surface 102 is the circumferential end of the first member 44 and the second member 64. The outer surface 102 is the portion of the outer circumferential surface of the first member 44 and the second member 64 from the end 48 or end 68 to the region where the male threaded portions 54 and 74 are formed. When viewed from the axial direction, the outer surface 102 is planar.

[0067] The gap G between end 48a and end 68a, and the gap G between end 48b and end 68b, form an upper space 106 that is wider in the axial direction on the end face 44c side of the upper part 44a than on the other parts. The upper end face 106a is the axial end face of the first member 44 and the second member 64 of the upper space 106.

[0068] The holes 108 open into the upper end faces 106a of each member and are formed toward the lower part 44b of the first member 44 and the lower part 64b of the second member 64. The holes 108 are through which the pin 130 of the connecting fitting 120 is inserted and removed.

[0069] The groove 110 is formed on the protruding surface 78Aa that protrudes into the gap G between the ends 48 and 68. The groove 110 is formed from the upper space 106 to the end faces of the lower parts 44b and 64b. The insertion portion 126 of the connecting fitting 120 is inserted into the groove 110.

[0070] (Connecting hardware) Figure 11 is a perspective view of the connecting fitting.

[0071] The connecting fittings 120 are inserted into opposing divisions 78A in the circumferential direction of the cylindrical portion 42 to connect the first member 44 and the second member 64. The connecting fittings 120 include a main body portion 122, an insertion portion 126, and a pin 130. In practice, one connecting fitting 120 is inserted into each of the opposing divisions 78A, but in Figure 11, only one connecting fitting 120 is shown.

[0072] When the main body 122 is connected to the first member 44 and the second member 64, it fits into the upper space 106. The main body 122 has pin holes 122a formed at both ends of the upper surface 122b, to which pins 130 are fixed. The pin holes 122a open to the upper surface 122b and penetrate through to the lower surface 122c. The pin holes 122a do not necessarily have to open from the lower surface 122c of the main body 122 and penetrate through to the upper surface 122b. The main body 122 has an insertion portion 126 between the pin holes 122a (in the center).

[0073] The insertion portion 126 is located in the center of the lower surface 122c of the main body portion 122 and extends in the direction opposite to the lower surface 122c. The insertion portion 126 is inserted from its tip into the groove portion 110 of the divided portion 78A. The insertion portion 126 is provided with a protrusion 128. The protrusion 128 is provided protruding from each side surface 126b of the insertion portion 126. Each protrusion 128 engages with the groove portion 110. The length of the protrusion 128 is the same as the length of the groove portion 110. A jig hole 126a is formed at the base of the insertion portion 126, into which the operating rod 96 of the jig 90 engages. The jig hole 126a penetrates from the inner surface 122d to the outer surface 122e of the main body portion 122.

[0074] The pin 130 is fixed to the pin hole 122a formed in the main body 122. The pin 130 is fixed to the pin hole 122a by welding. The pin 130 is inserted into the hole 108. The insertion of the pin 130 into the hole 108 stabilizes the insertion of the insertion part 126. The length of the pin 130 is shorter than the length of the protrusion 128. In this embodiment, the pin 130 is a spring pin. The pin 130 does not necessarily have to be fixed to the main body 122 by welding, and is not limited to a spring pin.

[0075] <How to remove> Next, the method for removing the guide sleeve 40A will be explained. Figure 12 is a schematic side view illustrating the method for inserting the connecting fitting. Figure 13 is a schematic side view illustrating the method for removing the guide sleeve according to the second embodiment.

[0076] With the connecting fitting 120 inserted into the guide sleeve 40A, the worker inserts the operating rod 96 of the jig 90 into the stud hole 12a by engaging it with the engaging edge 52a and the engaging edge 72a, as in the first embodiment. A more detailed explanation of the insertion method into the stud hole 12a is the same as in the first embodiment, so it will be omitted.

[0077] Although not shown in the diagram, if the guide sleeve 40A is not stuck, the worker engages the operating rod 96 of the jig 90 with the engaging portion 52 and the engaging portion 72, and rotates the jig 90 with the handle 92 to remove it.

[0078] If the guide sleeve 40A is fixed to the stud hole 12a, as shown in Figure 13, the worker pulls out one side of the connecting fitting 120 in the direction of arrow D (upwards). The worker engages the jig 90 with the jig hole 126a of the connecting fitting 120 and pulls it out in the direction of arrow D (upwards). The worker similarly pulls out the connecting fitting 120 on the other side. The guide sleeve 40A separates into a first member 44 and a second member 64 at the dividing section 78A. A gap G is created between the first member 44 and the second member 64 of the guide sleeve 40A, and the worker can remove the first member 44 by sliding it toward the center of the guide sleeve 40A. After removing the first member 44, the second member 64 can be similarly removed by sliding it toward the center of the guide sleeve 40A.

[0079] In the second embodiment, the guide sleeve 40A consists of a first member 44 and a second member 64, which are separated and joined together by a connecting fitting 120. Therefore, if the guide sleeve 40A becomes stuck to the stud hole 12a, the guide sleeve 40A can be separated by pulling out the connecting fitting 120, and the guide sleeve 40A can be easily removed from the stud hole 12a.

[0080] <Effects of this disclosure> The guide sleeves 40, 40A according to the first aspect of this disclosure are guide sleeves 40, 40A that are inserted into the threaded portion (stud hole 12a) of the reactor vessel body 12, and include a cylindrical portion 42 which comprises an arc-shaped first member 44 and a second member 64, with male threaded portions 54, 74 formed on a part of the outer circumferential surface and female threaded portions 56, 76 formed on a part of the inner circumferential surface, and dividing portions 78, 78A that connect the end 48 of the arc of the first member 44 and the end 68 of the arc of the second member 64, making the first member 44 and the second member 64 annular in shape.

[0081] According to this disclosure, if the guide sleeve becomes stuck to the stud hole of the reactor vessel body, the guide sleeve can be easily removed.

[0082] A guide sleeve according to a second aspect of this disclosure is the guide sleeve 40 according to the first aspect, wherein the divided portion 78 is a thin-walled portion 80 located in a part of the axial direction of the cylindrical portion 42, and the thin-walled portion 80 does not have male threaded portions 54, 74 and female threaded portions 56, 76 formed thereon. Therefore, the guide sleeve can be easily removed.

[0083] A guide sleeve according to a third aspect of this disclosure is a guide sleeve 40A according to the first aspect, wherein the divided portion 78A is a connecting fitting 120 that detachably connects the end 48 of the arc of the first member 44 and the end 68 of the arc of the second member 64. Therefore, the guide sleeve can be easily removed.

[0084] A guide sleeve according to a fourth aspect of this disclosure is a guide sleeve 40A according to a third aspect, wherein the connecting fitting 120 is inserted into a hole 108 formed in the first member 44 and a hole 108 formed in the second member 64, connecting the first member 44 and the second member 64. Therefore, the guide sleeve can be easily removed by pulling out the connecting fitting 120.

[0085] A fifth aspect of the present disclosure is a method for removing guide sleeves 40, 40A inserted into a threaded portion (stud hole 12a) of a reactor vessel body 12, wherein the guide sleeves 40, 40A include a first member 44 and a second member 64 which are arc-shaped, a cylindrical portion 42 which has male threaded portions 54, 74 formed on a part of its outer circumferential surface and female threaded portions 56, 76 formed on a part of its inner circumferential surface, and a dividing portion 78, 78A which connects the end 48 of the arc of the first member 44 and the end 68 of the second member 64, making the first member 44 and the second member 64 annular, and the method includes the steps of separating the first member 44 and the second member 64 by operating the dividing portion 78, 78A, and removing the separated first member 44 and the second member 64 from the threaded portion (stud hole 12a).Therefore, if the guide sleeve becomes stuck to the stud hole of the reactor vessel body, the guide sleeve can be easily removed.

[0086] Although embodiments of the present invention have been described above, the embodiments are not limited to those described herein. Furthermore, the aforementioned components include those that can be easily conceived by those skilled in the art, those that are substantially the same, and those that fall within the so-called equivalent range. Moreover, the aforementioned components can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the embodiments described above. [Explanation of Symbols]

[0087] 10 Pressurized water reactor 11 Reactor vessel 12. Reactor vessel body 12a Stud Hole 13 Reactor vessel lid 13a Through hole 14 Stud bolts 14a Male threaded section 15 nuts 40, 40A guide sleeve 42 Cylindrical section 44 First Member 44a Upper part 44b Lower part 48, 48a, 48b flat part 52 Engaging part 52a Engagement edge 52b Engagement hole 52ba, 52bb engagement hole 52c Hook section 54 Male threaded section 56 Female thread section 64 Second Member 64a Upper part 64b Lower part 68, 68a, 68b flat area 72 Engaging part 72a Engagement edge 72b Engagement hole 72ba engagement hole 72bb engagement hole 72c Hook part 74 Male threaded section 76 Female thread section 78, 78A split part 78Aa Protruding surface 80 Thin-walled section 80a 1st thin section 80b 2nd thin section 80cm gap 90 jigs 92 handle 94 Pillar section 96 Operation rod 98 Guide Studs 102 Exterior 106 Fitting part 106a Mating surface 108 Hole 110 groove 120 connecting fittings 122 Main body 122a Pin hole 122b Top surface 122c bottom side 122d inner surface 122e External surface 122f Side view 126 Insertion part 126a Jig hole 126b Side 128 Convex part 130 pins G Gap S Space

Claims

1. A guide sleeve inserted into the threaded portion of the reactor vessel body, A cylindrical portion comprising a first member and a second member having an arc shape, with a male threaded portion formed on a part of the outer circumferential surface and a female threaded portion formed on a part of the inner circumferential surface, The first member has a dividing portion that connects the end of the arc of the first member with the end of the arc of the second member, forming an annular shape between the first member and the second member. Guide sleeve.

2. The divided portion is a thin-walled portion located in a part of the axial direction of the cylindrical portion. The thin-walled portion does not have the male thread portion and the female thread portion formed therein. The guide sleeve according to claim 1.

3. The divided portion is a connecting fitting that is detachably connected to the end of the arc of the first member and the end of the arc of the second member. The guide sleeve according to claim 1.

4. The connecting fitting is inserted into the hole formed in the first member and the hole formed in the second member, thereby connecting the first member and the second member. The guide sleeve according to claim 3.

5. A method for removing a guide sleeve inserted into the threaded portion of the reactor vessel body, The guide sleeve includes a first member and a second member, both having an arc shape, a cylindrical portion having a male threaded portion formed on a part of its outer circumferential surface and a female threaded portion formed on a part of its inner circumferential surface, and a dividing portion that connects the end of the arc of the first member and the end of the arc of the second member, forming an annular shape between the first member and the second member. The steps include: operating the dividing portion to separate the first member and the second member; The step includes removing the separated first member and second member from the screw portion. How to remove the guide sleeve.

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