JP6491990B2 - Tubular body and method for producing tubular body - Google Patents

Description

  The present invention relates to a tubular body and a method for producing the tubular body, and more particularly, to a tubular body that can be used as a cladding tube that is inserted and used with nuclear fuel and a method for producing the tubular body.

  Today, in many nuclear reactors, nuclear fuel is contained in a cladding tube made of a sealed metal tube. Most cladding tubes are made of zirconium alloy or steel alloy. The cladding tube is designed so that radioactive gas and fission products are retained in the cladding tube and are not released to the outside even when the reactor is in operation or in the event of an accident.

  However, even if it is a boiling water reactor, if water is lost during operation, the generated nuclear fuel cannot be cooled, the cladding tube is melted, and hydrogen is generated by the reaction between the metal and water.

  In order to solve such a problem, Patent Document 1 discloses a tubular fiber-reinforced carbonaceous material composed of an aggregate made of SiC fibers formed by a winding method or a braided string method, and pyrolytic carbon filled between the SiC fibers. A nuclear fuel cladding tube comprising: a base material; and a SiC layer formed on at least an outer surface of the fiber-reinforced carbonaceous base material, wherein the SiC layer is used to decompose pyrolytic carbon on the surface of the fiber-reinforced carbonaceous base material. A reaction-converted CVR-SiC layer; and a CVD-SiC layer formed on the CVR-SiC layer. The nuclear fuel cladding tube is formed with the SiC layer of the fiber-reinforced carbonaceous substrate. A nuclear fuel cladding tube is described in which silicon atoms are diffused from the boundary region toward the inside of the fiber reinforced carbonaceous substrate.

  According to such a nuclear fuel cladding tube, since the surface of the ceramic fiber is in contact with the carbonaceous material, cracks caused by thermal stress can be stopped at the surface of the ceramic fiber, so that there are cracks penetrating the inside and outside of the tubular body. Hard to occur. In addition, since no pretreatment is required to provide coating on individual ceramic fibers, the process can be simplified, and the reactor can be operated at a higher temperature by improving the performance, so that an energy efficient nuclear reactor can be provided. In addition, it is described that the service life can be extended.

JP 2013-210372 A

  However, in the above-described invention, the portion made of SiC is only the trunk portion of the nuclear fuel cladding tube, and no investigation has been made on the structure of the opening portions at both ends. For this reason, an effective method for sealing the end of the nuclear fuel cladding tube is not provided, and there is no other method than applying a general connection structure.

  In the present invention, in view of the above problems, a tubular body having high strength and heat resistance and capable of forming an airtight structure in which a solid, liquid, gas or the like is sealed from the end of the tubular body and then closed and sealed. And it aims at providing the manufacturing method of a tubular body.

(1) A tubular body according to the present invention for solving the above-described problems is a tubular member composed of a tubular braid body made of ceramic fibers and a ceramic matrix that covers the braid body, and a first end portion of the tubular member. The inserted first end plug and the second end plug inserted into the second end of the cylindrical member and having a through hole, and the braided body includes the first end plug and / or the The ceramic member has a narrowed portion narrowed on the distal end side of the cylindrical member along the outer surface of the second end plug, and the ceramic matrix is joined to the first end plug and the second end plug.

According to the tubular body of the present invention, the tubular member is made of a ceramic / ceramic composite material because the tubular member is made of a cylindrical braid made of ceramic fibers and a matrix covering the braided body. It has strength and heat resistance and can be used in harsh environments.
Moreover, since it has the 1st end plug inserted in the 1st end part of the cylinder member, and the 2nd end plug inserted in the 2nd end part of the cylinder member, a tubular body is sealed. A tube or the like can be connected to the first end plug or the second end plug, and a tubular body having an airtight structure can be obtained.

In addition, the braided body has a narrowed portion in which the distal end side of the cylindrical member is narrowed along the outer surface of the first end plug and / or the second end plug, so even if the internal pressure of the cylindrical member increases, The structure in which one end plug or the second end plug cannot be removed from the cylindrical member can improve the connection reliability between the first end plug or the second end plug and the cylindrical member.
Moreover, since the ceramic matrix is joined to the first end plug and the second end plug, airtightness between the cylindrical member and the first end plug and the second end plug can be secured.
Furthermore, since the second end plug has a through hole, it can be closed and sealed after a solid, liquid, gas or the like is sealed inside the tubular body. For example, nuclear fuel, purge gas, etc. can be enclosed.

Furthermore, it is desirable that the tubular body of the present invention has the following aspect.
(2) The first end plug and / or the second end plug have a tapered surface along the narrowed portion of the cylindrical member.
Since the first end plug and / or the second end plug and the constricted portion of the cylindrical member are in contact with each other at the tapered surface, the bending stress applied to the ceramic fibers constituting the cylindrical member is relieved. Furthermore, since it contacts with a taper surface, the area which a 1st end plug or a 2nd end plug and a cylindrical member contact can be taken large, and connection reliability can be improved.

(3) The first end plug and / or the second end plug is made of any one of SiC, Ti ₃ SiC ₂ , Mo, W, Zircaloy, or FeCrAl.
Since these materials have high heat resistance and high strength and corrosion resistance, they can be suitably used as the first end plug or the second end plug of the tubular body. Since SiC or Ti ₃ SiC ₂ is a ceramic, it has particularly high heat resistance, and has high strength and corrosion resistance, so that it can be suitably used. Mo, W, Zircaloy, or FeCrAl is a metal having high heat resistance, high strength, and corrosion resistance, and can be easily welded and brazed and can be suitably used.

(4) The ceramic fiber is a SiC fiber.
The SiC fiber is a ceramic fiber having high heat resistance and high strength and corrosion resistance, and can be suitably used.

(5) The ceramic matrix is SiC.
SiC is a ceramic fiber having high heat resistance and high strength and corrosion resistance, and therefore can be suitably used.

(6) The first end plug has a cylindrical shape in which the opening end side of the cylindrical member is chamfered.
Since the first end plug has a cylindrical shape in which the opening end side of the cylindrical member is chamfered, the cylindrical member can be configured with the same inner diameter as the cylindrical member up to the chamfered portion of the first end plug. For this reason, it is possible to prevent the bent portion where stress concentration easily occurs from coming into contact with the internal space of the tubular body, and to obtain a high-strength tubular body.

(7) The second end plug has a barrel shape with tapered surfaces on both sides and a bulged central portion.
Since the second end plug has a barrel shape with a tapered surface on both sides and a bulged central portion, the second end plug has a tapered surface on both sides. For this reason, even if any of the internal pressure or the external pressure is applied to the end plug, it is possible to bond more firmly.

(8) The second end plug has an edge where the inner surface of the through hole and the tapered surface on the center side of the cylindrical member are in contact, and the cylindrical member is in contact with the edge.
The second end plug has an edge in contact with the inner surface of the through hole and the taper surface on the center side of the cylindrical member, and the cylindrical member has a structure in contact with the edge. Therefore, the inner diameter of the through hole and the inner diameter of the cylindrical member Can be made substantially the same. Thereby, when inserting a solid, interference with a through-hole can be eliminated. For example, the maximum size solid that can be inserted into the cylindrical member can be inserted without being affected by the size of the through hole. This is advantageous when inserting nuclear fuel pellets.

(9) A third end plug is further inserted into the through hole.
Since the third end plug is inserted into the through hole, the third end plugs can be fitted with each other with high dimensional accuracy, and high airtightness can be ensured.

Next, the cladding tube of this invention for solving the said subject is demonstrated.
(10) The cladding tube of the present invention is a cladding tube for a nuclear reactor using the tubular body.
The cladding tube of the present invention includes a cylindrical braided body made of ceramic fibers, a cylindrical member made of a matrix covering the braided body, a first end plug inserted into a first end of the cylindrical member, and a cylindrical member A second end plug inserted into the second end, and the braided body is a narrowed portion in which the distal end side of the tubular member is narrowed along the outer surface of the first end plug and / or the second end plug And the ceramic matrix is bonded to the first end plug and / or the second end plug. For this reason, while having high airtightness, it has high heat resistance, high strength, and corrosion resistance, and can be suitably used as a cladding tube for a nuclear reactor.

Next, the manufacturing method of the tubular body of this invention for solving the said subject is demonstrated.
(11) In the method for manufacturing a tubular body of the present invention, a first end plug is combined with a first end portion of a mandrel, a second end plug having a through hole is inserted into a second end portion of the mandrel, and a mandrel is inserted. A mandrel preparation step for preparing an assembly, a braiding step for weaving ceramic fibers on the surface of the mandrel assembly to form a braided body, and a cylindrical member by forming a ceramic matrix between the ceramic fibers of the braided body A matrix forming step of forming, and a mandrel extraction step of removing the mandrel from the cylindrical member leaving the first end plug and the second end plug, and the cylindrical member includes the first end plug And / or having a constriction along the outer surface of the second end plug.
A separately manufactured braid may be combined with the mandrel assembly.

According to the method for manufacturing a tubular body of the present invention, the first end plug is combined with the first end of the mandrel, the second end of the mandrel is inserted into the second end plug having a through hole, and the mandrel assembly is assembled. Since it has the mandrel preparation process which prepares a solid | solid, a 1st end plug and a 2nd end plug can be arrange | positioned correctly at the both ends of a tubular body.
In addition, since it has a braiding step of weaving ceramic fibers on the surface of the mandrel assembly to form a braided body, a cylindrical member extending from the first end plug to the second end plug is formed with high dimensional accuracy. be able to.

Furthermore, since it has the matrix formation process which forms a ceramic member between the ceramic fibers of a braid body, and forms a cylindrical member, a ceramic fiber reinforced ceramic composite material with high intensity | strength can be obtained.
The matrix forming step may be any process and is not particularly limited.
In the matrix forming step, a precursor method in which the ceramic precursor is immersed in a liquid and the ceramic precursor is fired to form a ceramic matrix can be used.
In the matrix forming step, a CVD method in which a source gas is introduced to form a CVD film in a CVD furnace can be used.
Furthermore, a CVD method and a precursor method can be used in combination.

In addition, since it has a mandrel extraction process that leaves the first end plug and the second end plug from the cylindrical member, it is closed after the solid, liquid, gas, etc. are sealed inside the tubular body. A sealed structure can be formed. In addition, since the 2nd end plug has a through-hole, a mandrel can be extracted easily.
The cylindrical member has a narrowed portion along the outer surface of the first end plug and / or the second end plug.

Moreover, since the tubular body obtained in this way has a tubular member made of a cylindrical braid made of ceramic fibers and a matrix covering the braided body, the tubular member is a ceramic / ceramic composite material, It has high strength and heat resistance and can be used in harsh environments.
Moreover, since it has the 1st end plug inserted in the 1st end part of the cylinder member, and the 2nd end plug inserted in the 2nd end part of the cylinder member, a tubular body is sealed. A tube or the like can be connected to the first end plug or the second end plug, and a tubular body having an airtight structure can be obtained.
Further, the braided body has a narrowed portion in which the distal end side of the tubular member is narrowed along the outer surface of the first end plug and / or the second end plug, so that the first end plug or the second end plug A structure in which the plug does not come off from the cylindrical member can be taken, and the connection reliability between the first end plug or the second end plug and the cylindrical member can be improved.
Moreover, since the ceramic matrix is joined to the first end plug and the second end plug, airtightness between the cylindrical member and the first end plug and the second end plug can be secured.
Furthermore, since the second end plug has a through hole, it can be closed and sealed after a solid, liquid, gas or the like is sealed inside the tubular body. For example, nuclear fuel, purge gas, etc. can be enclosed.

Furthermore, it is desirable that the method for manufacturing a tubular body of the present invention is as follows.
(12) The first end plug and / or the second end plug have a tapered surface along the narrowed portion of the cylindrical member.
Since the first end plug and / or the second end plug and the constricted portion of the cylindrical member are in contact with each other at the tapered surface, the bending stress applied to the ceramic fibers constituting the cylindrical member is relieved. Furthermore, since it contacts with a taper surface, the area which a 1st end plug or a 2nd end plug and a cylindrical member contact can be taken large, and connection reliability can be improved.

(13) The first end plug and / or the second end plug is made of any one of SiC, Ti ₃ SiC ₂ , Mo, W, Zircaloy, or FeCrAl.
Since these materials have high heat resistance and high strength and corrosion resistance, they can be suitably used as the first end plug or the second end plug of the tubular body. Since SiC or Ti ₃ SiC ₂ is a ceramic, it has particularly high heat resistance, and has high strength and corrosion resistance, so that it can be suitably used. Mo, W, Zircaloy, or FeCrAl is a metal having high heat resistance, high strength, and corrosion resistance, and can be easily welded and brazed and can be suitably used.

(14) The ceramic fiber is a SiC fiber.
The SiC fiber is a ceramic fiber having high heat resistance and high strength and corrosion resistance, and can be suitably used.

(15) The ceramic matrix is SiC.
SiC is a ceramic fiber having high heat resistance and high strength and corrosion resistance, and therefore can be suitably used.

(16) The first end plug has a cylindrical shape in which the opening end side of the cylindrical member is chamfered.
Since the first end plug has a cylindrical shape in which the opening end side of the cylindrical member is chamfered, the cylindrical member can be configured with the same inner diameter as the cylindrical member up to the chamfered portion of the first end plug. For this reason, it is possible to prevent the bent portion where stress concentration easily occurs from coming into contact with the internal space of the tubular body, and to obtain a high-strength tubular body.

(17) The second end plug has a barrel shape with tapered surfaces on both sides and a bulged central portion.
Since the 2nd end plug is a barrel shape which has a taper surface on both sides and the center part swelled, it has a taper surface on both sides. For this reason, even if any of the internal pressure or the external pressure is applied to the end plug, it is possible to bond more firmly.

(18) The second end plug has an edge where the inner surface of the through hole and the tapered surface on the center side of the cylindrical member are in contact, and the cylindrical member is in contact with the edge.
Since the second end plug has an edge where the inner surface of the through hole and the taper surface on the center side of the cylindrical member are in contact, and the cylindrical member is in contact with the edge, the inner diameter of the through hole and the inner diameter of the cylindrical member Can be made substantially the same, and interference with the through-hole can be eliminated when the solid is inserted. For example, the maximum size solid that can be inserted into the cylindrical member can be inserted without being affected by the size of the through hole. This is advantageous when inserting nuclear fuel pellets.
In addition, since the inner diameters of the second end plug and the cylindrical member can be made the same, the inner surface of the cylindrical member can be accurately held even if a straight mandrel is used. For this reason, the dimensional accuracy of the obtained tubular body can be improved.

(19) A third end plug is further inserted into the through hole.
Since the third end plug is inserted into the through hole, the third end plugs can be fitted with each other with high dimensional accuracy, and high airtightness can be ensured.

Next, the manufacturing method of the cladding tube of this invention for solving the said subject is demonstrated.
(20) In the cladding tube manufacturing method of the present invention, a reactor cladding tube is manufactured using the tubular body.
A cladding tube manufactured by the method for manufacturing a cladding tube of the present invention includes a cylindrical braided body made of ceramic fibers, a cylindrical member made of a matrix covering the braided body, and a first inserted into the first end of the cylindrical member. One end plug and a second end plug inserted into the second end of the cylindrical member. The braided body has a narrowed portion in which the distal end side of the tubular member is narrowed along the outer surface of the first end plug and / or the second end plug, and the ceramic matrix has the first end plug and / or the second end plug. Since it is joined to the end plug, it has high airtightness, high heat resistance, high strength, and corrosion resistance, and can be suitably used as a cladding tube for a nuclear reactor.

  According to the tubular body of the present invention, the tubular member is made of a ceramic / ceramic composite material because the tubular member is made of a cylindrical braid made of ceramic fibers and a matrix covering the braided body. It has strength and heat resistance and can be used in harsh environments. Moreover, since it has the 1st end plug inserted in the 1st end part of the cylinder member, and the 2nd end plug inserted in the 2nd end part of the cylinder member, a tubular body is sealed. A tube or the like can be connected to the first end plug or the second end plug, and a tubular body having an airtight structure can be obtained. Further, since the braided body has a narrowed portion where the distal end side of the cylindrical member is narrowed along the outer surface of the first end plug and / or the second end plug, the first end plug or the second end plug A structure in which the end plug does not come off from the cylindrical member can be taken, and the connection reliability between the first end plug or the second end plug and the cylindrical member can be improved. Moreover, since the ceramic matrix is joined to the first end plug and the second end plug, airtightness between the cylindrical member and the first end plug and the second end plug can be secured. Furthermore, since the second end plug has a through-hole, it can be closed and sealed after sealing solid, liquid, gas, etc. inside the tubular body, for example, nuclear fuel, purge gas, etc. Can be encapsulated.

(A) is sectional drawing of the tubular body which concerns on this embodiment, (B) is an enlarged view of "B" part in (A), (C) is an enlarged view of "C" part in (A). It is. It is process drawing which shows the manufacturing method of a tubular body. (A) It is sectional drawing which shows the mandrel assembly in a mandrel preparation process, (B) is a front view. (A) is explanatory drawing which shows the state which forms a braid body in a braiding process, (B) is a whole figure of the apparatus which winds a ceramic fiber around a mandrel assembly and forms a braid body, (C) FIG. 3 is a perspective view of a formed braided body. It is a front view which shows a matrix formation process. It is a front view which shows a mandrel extraction process. (A)-(D) are sectional drawings which show the modification of a 1st end part and a 1st end plug. (A)-(C) are sectional drawings which show the modification of a 2nd end part and a 2nd end plug.

The tubular body of the present invention will be described.
The tubular body of the present invention has, for example, a cylindrical tube member. The cylindrical member has a cylindrical braided body made of ceramic fibers such as SiC fibers, and a ceramic matrix such as SiC covering the braided bodies.

  The braided body has a hollow portion along the longitudinal direction, and is open at a first end that is one end and a second end that is the other end. The first end portion of the braided body has a constricted portion formed of a truncated cone-shaped tapered surface that decreases in diameter toward the outside in the longitudinal direction. In addition, the second end of the braided body is continuous with the first taper that is once expanded in the longitudinal direction, the first taper, the concentric parallel part with the hollow part, and the parallel part. A second taper having a reduced diameter is provided. Therefore, the second end portion has a barrel shape in which the central portion is swollen.

  Since the tubular member is formed by covering the braided body thus formed with a ceramic matrix, both longitudinal ends of the tubular member have the same shape as the first end and the second end of the braided body. doing.

A first end plug is inserted into the first end of the cylindrical member.
Since the first end portion has a stenosis portion whose diameter decreases toward the outside in the longitudinal direction, the tip end portion of the first end plug has a shape corresponding to the stenosis portion. That is, the tip of the first end plug has a tapered surface along the tapered surface of the narrowed portion. Moreover, the recessed part dented in the front-end | tip part side is provided in the inner side edge part (end part on the opposite side to a front-end | tip part) of a 1st end plug. The first end plug is joined to the ceramic matrix.
The first end plug is preferably made of any one of SiC, Ti ₃ SiC ₂ , Mo, W, Zircaloy, or FeCrAl.

A second end plug is inserted into the second end of the cylindrical member.
The second end portion has a barrel shape in which the central portion swells, and the second end plug has a barrel shape corresponding to the second end portion. That is, the second end plug includes a first tapered surface along the first taper of the second end of the braided body, a parallel part along the parallel part of the braided body, and a second taper of the braided body. Having a second tapered surface. And a 2nd end plug has a through-hole which penetrates a center part. The longitudinal direction center side edge (edge) of the inner surface of the through hole is in contact with the first taper of the cylindrical member. Here, the edge coincides with the joint point between the first taper of the cylindrical member and the inner surface of the hollow portion, and the hollow portion and the through hole are smoothly continuous. The second end plug is bonded to the ceramic matrix.
The second end plug is preferably made of any one of SiC, Ti ₃ SiC ₂ , Mo, W, Zircaloy, or FeCrAl.

A third end plug is attached to the through hole of the second end plug. The third end plug is detachable and attached to the through hole to seal the hollow portion of the cylindrical member.
The third end plug is preferably made of any one of SiC, Ti ₃ SiC ₂ , Mo, W, Zircaloy, or FeCrAl.

  Such a cylindrical member can be used as a cladding tube for a nuclear reactor.

Next, the manufacturing method of the tubular body of this invention is demonstrated.
The manufacturing method of a tubular body has a mandrel preparation process, a braiding process, a matrix formation process, and a mandrel extraction process.
In the mandrel preparation step, a first end plug is combined with the first end of the mandrel. At this time, a convex portion that fits into the concave portion provided in the first end plug is provided on the end surface on the first end portion side of the mandrel, and the convex portion is fitted into the concave portion and combined. Further, a second end plug is combined with the second end side of the mandrel. At this time, the mandrel assembly is manufactured by inserting the second end side of the mandrel into the through hole of the second end plug.

In the braiding process, the braided body is formed by weaving ceramic fibers on the surface of the mandrel assembly using the braided body forming apparatus. In a braided body forming device, braided yarns (ceramic fibers) are entangled and arranged on a mandrel assembly from a plurality of bobbins that run on a horizontal disc, and at the same time, warp yarns (ceramic fibers) that pass through the center hole of the disc Are arranged along the axial direction of the mandrel assembly to form a triaxial weave braid.
Although the braided body is formed by weaving thread-like ceramic fibers on the peripheral surface of the mandrel assembly, it is also possible to form a braided body by covering the mandrel assembly with ceramic fibers previously knitted into a cylindrical shape. is there.

In the matrix forming step, a ceramic matrix is formed between the ceramic fibers of the braided body to form a cylindrical member.
In the mandrel extraction step, the mandrel is extracted from the cylindrical member on which the ceramic matrix is formed, leaving the first end plug and the second end plug. Further, unnecessary portions at both ends of the cylindrical member are appropriately cut.
A tubular body is manufactured by the above process. The tubular body is used as a cladding tube for a nuclear reactor.

Hereinafter, modes for carrying out the invention will be described.
As shown in FIG. 1 (A), the tubular body 10 of the present embodiment includes, for example, a cylindrical tube member 20. As shown in FIGS. 1B and 1C, the cylindrical member 20 includes a cylindrical braid body 21 made of ceramic fibers such as SiC fibers, and a ceramic matrix 22 such as SiC covering the braid bodies 21. And have.

  The braided body 21 has a hollow portion 211 along the longitudinal direction. The first end portion 23 is one end portion (the right end in FIG. 1A) and the other end portion (the left end in FIG. 1A). The second end 24 is open. The first end portion 23 of the braided body 21 has a constricted portion 25 formed by a truncated cone-shaped tapered surface 251 whose diameter decreases toward the outside in the longitudinal direction. Further, the second end portion 24 of the braided body 21 has a first taper 241 that is once expanded in diameter in the longitudinal direction, a parallel portion 242 that is continuous with the first taper 241 and is concentric with the hollow portion 211, A second taper 243 that continuously reduces the diameter of the parallel portion 242 is provided. Therefore, the 2nd end part 24 is exhibiting the barrel shape which the center part swelled.

Since the tubular member 20 is formed by covering the braided body 21 formed in this way with the ceramic matrix 22, both longitudinal ends of the tubular member 20 are connected to the first end 23 and the second end of the braided body 21. The shape is the same as that of the portion 24.
In the following description, the indication of the first end 23 and the second end 24 of the braided body 21 is used in common with the first end 23 and the second end 24 of the tubular member 20. To do. In addition, the display of the narrowed portion 25 of the braided body 21 is also used in common with the narrowed portion 25 of the tubular member 20.

As shown in FIG. 1C, a first end plug 31 is inserted into the first end portion 23 of the cylindrical member 20.
Since the first end portion 23 has a constricted portion 25 whose diameter decreases toward the outside in the longitudinal direction, the distal end portion of the first end plug 31 has a shape corresponding to the constricted portion 25. That is, the tip of the first end plug 31 has a tapered surface 311 along the tapered surface 251 of the narrowed portion 25. In addition, a concave portion 312 that is recessed toward the distal end portion side is provided on the inner end portion (end portion opposite to the distal end portion) of the first end plug 31. The first end plug 31 is joined to the ceramic matrix 22.
The first end plug 31 is preferably made of any one of SiC, Ti ₃ SiC ₂ , Mo, W, Zircaloy, or FeCrAl.

As shown in FIG. 1B, a second end plug 32 is inserted into the second end portion 24 of the cylindrical member 20.
The second end portion 24 has a barrel shape in which the central portion swells, and the second end plug 32 has a barrel shape corresponding to the second end portion 24. That is, the second end plug 32 includes a first tapered surface 321 along the first taper 241 of the second end 24 of the braided body 21, and a parallel part 322 along the parallel part 242 of the braided body 21. The second taper surface 323 extends along the second taper 243 of the braid body 21. And the 2nd end plug 32 has the through-hole 324 which penetrates a center part. A longitudinal center side end (edge 325) of the inner surface of the through hole 324 is in contact with the first taper 241 of the cylindrical member 20. Here, the edge 325 coincides with the joint point between the first taper 241 of the cylindrical member 20 and the inner surface 212 of the hollow portion 211, and the hollow portion 211 and the through hole 324 are smoothly continuous. The second end plug 32 is bonded to the ceramic matrix 22.
The second end plug 32 is preferably made of any one of SiC, Ti ₃ SiC ₂ , Mo, W, Zircaloy, or FeCrAl.

A third end plug 33 is attached to the through hole 324 of the second end plug 32. The third end plug 33 is detachable and can be attached to the through hole 324 to seal the hollow portion 211 of the cylindrical member 20.
The third end plug 33 is preferably made of any one of SiC, Ti ₃ SiC ₂ , Mo, W, Zircaloy, or FeCrAl.

  Such a cylindrical member 20 can be used as a cladding tube for a nuclear reactor.

Next, the manufacturing method of the tubular body 10 of this embodiment is demonstrated.
As shown in FIG. 2, the method for manufacturing the tubular body 10 includes a mandrel preparation step S1, a braiding step S2, a matrix formation step S3, and a mandrel extraction step S4.
As shown in FIGS. 3A and 3B, in the mandrel preparation step S <b> 1, the first end plug 31 is combined on the first end portion 23 side of the mandrel 41. At this time, a convex portion 42 that fits into the concave portion 312 provided in the first end plug 31 is provided on the end surface of the mandrel 41 on the first end portion 23 side, and the convex portion 42 is fitted into the concave portion 312. Let them combine. Furthermore, the second end plug 32 is combined with the second end 24 side of the mandrel 41. At this time, the mandrel assembly 43 is manufactured by inserting the second end 24 side of the mandrel 41 into the through hole 324 of the second end plug 32.

As shown in FIG. 4A, in the braiding step S2, the braided body 21 is formed by weaving ceramic fibers 44 on the surface of the mandrel assembly 43. FIG. 4B shows an example of a braid body forming apparatus 45 that forms the braid body 21. In this braided body forming apparatus 45, braided yarns 441 (ceramic fibers 44) are entangled and arranged on a mandrel assembly 43 from a plurality of bobbins 47 running on a horizontal disk 46, and at the same time, a central hole 461 of the disk 46. The warp yarns 442 (ceramic fibers 44) passing through are arranged along the axial direction of the mandrel assembly 43 to form a triaxial weave braid 21 (see FIG. 4C).
In FIG. 4, the braided body 21 is formed by weaving the thread-like ceramic fibers 44 on the peripheral surface of the mandrel assembly 43, but the mandrel assembly 43 is covered with a braided ceramic fiber in advance. It is also possible to form the braided body 21.

As shown in FIG. 5, in the matrix forming step S <b> 3, the cylindrical matrix 20 is formed by forming the ceramic matrix 22 between the ceramic fibers 44 of the braided body 21.
As shown in FIG. 6, in the mandrel extraction step S <b> 4, the mandrel 41 is extracted from the cylindrical member 20 on which the ceramic matrix 22 is formed, leaving the first end plug 31 and the second end plug 32. Further, unnecessary portions at both ends of the cylindrical member are appropriately cut.
The tubular body 10 is manufactured by the above process. The tubular body 10 is used as a cladding tube for a nuclear reactor.

Next, operations and effects of the tubular body 10 of the present embodiment will be described.
According to the tubular body 10 of this embodiment, it has the cylindrical member 20 which consists of the cylindrical braid body 21 which consists of ceramic fibers 44, and the ceramic matrix 22 which covers the braid body 21. FIG. Since the cylindrical member 20 is a ceramic / ceramic composite material and has high strength and heat resistance, it can be used even in harsh environments.
Moreover, since it has the 1st end plug 31 inserted in the 1st end part 23 of the cylinder member 20, and the 2nd end plug 32 inserted in the 2nd end part 24 of the cylinder member 20, The tubular body 10 can be sealed or used by connecting a tube or the like to the first end plug 31 or the second end plug 32, and the tubular body 10 having an airtight structure can be obtained.

Further, the braided body 21 has the narrowed portion 25 in which the distal end side of the cylindrical member 20 is narrowed along the outer surface of the first end plug 31, so that even if the internal pressure of the cylindrical member 20 increases, the first end A structure in which the plug 31 does not come off from the cylindrical member 20 can be taken, and the connection reliability between the first end plug 31 and the cylindrical member 20 can be improved.
Further, since the ceramic matrix 22 is joined to the first end plug 31 and the second end plug 32, the airtightness between the cylindrical member 20 and the first end plug 31 and the second end plug 32 is improved. Can be secured.
Furthermore, since the second end plug 32 has the through-hole 324, after the solid, liquid, gas or the like is sealed inside the tubular body 10, it can be closed and sealed. For example, nuclear fuel, purge gas, etc. can be enclosed.

  According to the tubular body 10 of the present embodiment, the first end plug 31 and the narrowed portion 25 of the cylindrical member 20 are in contact with each other at the tapered surface 251, so that the bending stress applied to the ceramic fibers 44 constituting the cylindrical member 20. To ease. Furthermore, since it contacts with the taper surface 251, the contact area of the 1st end plug 31 and the cylinder member 20 can be taken large, and connection reliability can be improved.

According to the tubular body 10 of the present embodiment, the first end plug 31 and the second end plug 32 are made of any one of SiC, Ti ₃ SiC ₂ , Mo, W, Zircaloy, or FeCrAl. Since these materials have high heat resistance and high strength and corrosion resistance, they can be suitably used as the first end plug 31 or the second end plug 32 of the tubular body 10. Since SiC or Ti ₃ SiC ₂ is a ceramic, it has particularly high heat resistance, and has high strength and corrosion resistance, so that it can be suitably used. Mo, W, Zircaloy or FeCrAl is a metal having high heat resistance, high strength and corrosion resistance, and can be easily welded and brazed, and can be suitably used.

  According to the tubular body 10 of the present embodiment, the ceramic fiber 44 is a SiC fiber. Since the SiC fiber is a ceramic fiber 44 having high heat resistance and high strength and corrosion resistance, it can be suitably used.

  According to the tubular body 10 of the present embodiment, the ceramic matrix 22 is SiC. Since SiC is a ceramic fiber 44 having high heat resistance, high strength and corrosion resistance, it can be suitably used.

  According to the tubular body 10 of the present embodiment, the first end plug 31 has a cylindrical shape in which the opening end side of the cylindrical member 20 is chamfered, so that the cylindrical member 20 extends to the chamfered portion of the first end plug 31. It can be configured with the same inner diameter as the cylindrical member 20. For this reason, it is possible to prevent the bent portion where stress concentration easily occurs from coming into contact with the hollow portion 211 of the tubular body 10, and to obtain the high-strength tubular body 10.

  According to the tubular body 10 of the present embodiment, the second end plug 32 has a barrel shape with tapered surfaces 251 on both sides and an inflated central portion, so the first taper 241 and the second taper on both sides. 243. For this reason, even if any of the internal pressure and the external pressure is applied to the second end plug 32, the second end plug 32 and the cylinder can be more firmly coupled and can be structured so as not to come off the cylinder member 20. Connection reliability with the member 20 can be improved.

  According to the tubular body 10 of the present embodiment, the second end plug 32 has the edge 325 where the inner surface of the through hole 324 and the tapered surface 251 on the center side of the cylindrical member 20 are in contact with each other, and the cylindrical member 20 Since the structure is in contact with 325, the inner diameter of the through hole 324 and the inner diameter of the cylindrical member 20 can be made substantially the same. Thereby, when inserting solid, interference with the through-hole 324 can be eliminated. For example, the maximum size solid that can be inserted into the cylindrical member 20 can be inserted without being affected by the size of the through hole 324. This is advantageous when inserting nuclear fuel pellets.

  According to the tubular body 10 of the present embodiment, since the third end plug 33 is inserted into the through hole 324, they can be fitted with each other with high dimensional accuracy, and high airtightness can be ensured.

  A tubular body 10 is used for the cladding tube of this embodiment. Accordingly, the tubular braid body 21 made of the ceramic fiber 44, the tubular member 20 made of the ceramic matrix 22 covering the braid body 21, and the first end plug 31 inserted into the first end portion 23 of the tubular member 20; And a second end plug 32 inserted into the second end 24 of the cylindrical member 20. The braided body 21 has a narrowed portion 25 in which the distal end side of the cylindrical member 20 is narrowed along the outer surface of the first end plug 31, and the second end plug 32 has a barrel shape. The ceramic matrix 22 is joined to the first end plug 31 and the second end plug 32. For this reason, while having high airtightness, it has high heat resistance, high strength, and corrosion resistance, and can be suitably used as a cladding tube for a nuclear reactor.

According to the manufacturing method of the tubular body 10 of this embodiment, it has mandrel preparation process S1. In the mandrel preparation step S1, the first end plug 31 is combined with the first end portion 23 of the mandrel 41, the second end portion 24 of the mandrel 41 is inserted into the second end plug 32 having the through hole 324, and the mandrel An assembly 43 is prepared. For this reason, the first end plug 31 and the second end plug 32 can be accurately arranged at both ends of the tubular body 10.
Moreover, since it has the braiding process S2 which weaves the ceramic fiber 44 on the surface of the mandrel assembly 43 and forms the braided body 21, the cylindrical member extending from the first end plug 31 to the second end plug 32 20 can be formed with high dimensional accuracy.

Furthermore, since it has the matrix formation process S3 which forms the cylindrical member 20 by forming the ceramic matrix 22 between the ceramic fibers 44 of the braided body 21, a ceramic fiber reinforced ceramic composite material having high strength can be obtained.
The matrix forming step S3 may be any process and is not particularly limited.
In the matrix formation step, a precursor method in which the ceramic precursor is immersed in a liquid and the ceramic precursor is fired to form the ceramic matrix 22 can be used. In the matrix forming step, a CVD method in which a source gas is introduced to form a CVD film in a CVD furnace can be used. Furthermore, a CVD method and a precursor method can be used in combination.

Further, since the mandrel extraction step S4 for extracting the mandrel 41 from the cylindrical member 20 while leaving the first end plug 31 and the second end plug 32 is provided, solids, liquids, gases, and the like are placed inside the tubular body 10. After encapsulating, it can be closed to form a sealed structure. In addition, since the 2nd end plug 32 has the through-hole 324, the mandrel 41 can be extracted easily.
Since the cylindrical member 20 has the narrowed portion 25 along the outer surface of the first end plug 31 at the first end portion 23, the mandrel 41 can be pulled out toward the second end portion 24 side.

Moreover, since the tubular body 10 obtained in this way has the cylindrical braided body 21 made of the ceramic fibers 44 and the cylindrical member 20 made of the ceramic matrix 22 covering the braided body 21, the tubular member 20 is It is a ceramic / ceramic composite, has high strength and heat resistance, and can be used in harsh environments.
Moreover, since it has the 1st end plug 31 inserted in the 1st end part 23 of the cylinder member 20, and the 2nd end plug 32 inserted in the 2nd end part 24 of the cylinder member 20, The tubular body 10 can be sealed or used by connecting a tube or the like to the first end plug 31 or the second end plug 32, and the tubular body 10 having an airtight structure can be obtained.

Further, the braided body 21 has the narrowed portion 25 in which the distal end side of the cylindrical member 20 is narrowed along the outer surface of the first end plug 31, so that the first end plug 31 does not come out of the cylindrical member 20. A structure can be taken and the connection reliability of the 1st end plug 31 and the cylinder member 20 can be improved.
Moreover, since the 2nd end plug 32 is the barrel shape which has the taper surface 251 on both sides and the center part swelled, it has the 1st taper 241 and the 2nd taper 243 on both sides. For this reason, even if any of the internal pressure and the external pressure is applied to the second end plug 32, the second end plug 32 and the cylinder can be more firmly coupled and can be structured so as not to come off the cylinder member 20. Connection reliability with the member 20 can be improved.
Further, since the ceramic matrix 22 is joined to the first end plug 31 and the second end plug 32, the airtightness between the cylindrical member 20 and the first end plug 31 and the second end plug 32 is improved. Can be secured.
Furthermore, since the second end plug 32 has the through-hole 324, after the solid, liquid, gas or the like is sealed inside the tubular body 10, it can be closed and sealed. For example, nuclear fuel, purge gas, etc. can be enclosed.

The tubular body 10 of the present invention is not limited to the above-described embodiment, and appropriate modifications and improvements can be made.
For example, in the present embodiment, the narrowed portion 25 is provided at the first end portion 23 of the tubular body 10, but may be provided at the second end portion 24. Further, it can be provided on both sides of the first end portion 23 and the second end portion 24.

Further, the shapes of the first end plug 31 and the second end plug 32 are not limited to the shapes of the above-described embodiments.
Below, the modification of the 1st end part 23 and the 1st end plug 31 of the tubular body 10 is shown.
In the tubular body 101 shown in FIG. 7A, the shape of the first end portion 23 is the same as that of the above-described embodiment, but a recess 312 (see FIG. 1C) is formed on the inner end surface of the first end plug 31A. It is not provided and is flat. Even if it does in this way, the effect | action and effect similar to the tubular body 10 of embodiment mentioned above can be acquired.

  Further, in the tubular body 102 shown in FIG. 7B, an enlarged diameter portion 231 that protrudes outward is provided on the outer peripheral surface of the first end portion 23 </ b> A, and a concave portion 232 is provided on the inner surface of the tubular member 20. ing. The narrowed portion 25 (see FIG. 1C) described above is not provided. Correspondingly, the first end plug 31B is provided with a convex portion 313 that fits into the concave portion 232. Even if it does in this way, while being able to acquire the effect | action and effect similar to the tubular body 10 of embodiment mentioned above, even if the force which pushes the 1st end plug 31B to the center side of the cylinder member 20 acts further. , Can be prevented from moving.

The tubular body 103 shown in FIG. 7C has the same shape as the tubular body 10 of the above-described embodiment, but the inside and outside of the tubular body 103 are connected to the center of the first end plug 31C. A communication hole 314 that communicates is provided. This is suitable when a mandrel 41 having a protrusion 421 at the tip is used.
Further, in the tubular body 104 shown in FIG. 7D, a convex portion 315 is provided on the inner surface of the first end plug 31D in place of the concave portion 312 (see FIG. 1C).

Next, a modification of the second end 24 and the second end plug 32 of the tubular body 10 will be shown.
In the tubular body 105 shown in FIG. 8A, the size of the through hole 324 of the second end plug 32A is smaller than the inner diameter of the hollow portion 211 of the cylindrical member 20 (see FIG. 1B). In this case, when the second end plug 32A is manufactured, the portion 213 corresponding to the thickness of the second end plug 32A is filled with, for example, combustible material or sand, and the size of the through hole 324 is centered. It is possible to manufacture the second end plug 32A by inserting a bar member 34 corresponding to the above. After the second end plug 32A is manufactured, the bar member 34 is extracted, and combustible materials, sand, and the like are removed.

  In the tubular body 106 shown in FIG. 8B, the cross-sectional shape of the second end plug 32B is flat compared to the barrel-shaped second end plug 32 in the above-described embodiment.

In the tubular body 107 shown in FIG. 8C, a threaded portion 326 is formed on the inner surface of the through hole 324 of the second end plug 32C. The threaded portion 326 can be provided by providing a thread on the rod member 34 of FIG. Alternatively, the threaded portion 326 can be formed after the second end plug 32C is formed.
Thereby, another member can be easily attached to and detached from the second end plug 32C.

  The present invention is applicable to a tubular body that can be used, for example, as a cladding tube to which nuclear fuel is inserted.

DESCRIPTION OF SYMBOLS 10 Tubular body 20 Tubular member 21 Braided body 22 Ceramic matrix 23 1st end part 24 2nd end part 25 Constriction part 251 Tapered surface 31 1st end plug 32 2nd end plug 321 1st taper surface (taper surface)
323 Second taper surface (taper surface)
324 Through hole 325 Edge 33 Third end plug 41 Mandrel 43 Mandrel assembly 44 Ceramic fiber S1 Mandrel preparation step S2 Braiding step S3 Matrix formation step S4 Mandrel extraction step

Claims (20)

A cylindrical member made of a ceramic braid made of ceramic fiber and a ceramic matrix covering the braided body, a first end plug inserted into a first end of the cylindrical member, and a second end of the cylindrical member A second end plug inserted into the part and having a through hole,
The braided body has a narrowed portion in which a distal end side of the cylindrical member is narrowed along an outer surface of the first end plug and / or the second end plug, and the ceramic matrix is formed of the first end plug. And a tubular body characterized by being joined to the second end plug.   2. The tubular body according to claim 1, wherein the first end plug and / or the second end plug have a tapered surface along a narrowed portion of the cylindrical member. Wherein the first end plug and / or the second end _{plug, SiC, Ti 3 SiC 2,} Mo, W, according to claim 1 or claim 2, characterized in that it consists either of Zircaloy or FeCrAl Tubular body.   The tubular body according to any one of claims 1 to 3, wherein the ceramic fiber is a SiC fiber.   The tubular body according to any one of claims 1 to 4, wherein the ceramic matrix is SiC.   The tubular body according to any one of claims 1 to 5, wherein the first end plug has a cylindrical shape in which an opening end side of the cylindrical member is chamfered.   The tubular body according to any one of claims 1 to 5, wherein the second end plug has a barrel shape with tapered surfaces on both sides and a center portion swelled.   The said 2nd end plug has an edge which the inner surface of the said through-hole and the taper surface of the center side of a cylinder member contact, The said cylinder member contacts the said edge. Tubular body.   The tubular body according to claim 8, wherein a third end plug is further inserted into the through hole.   A cladding tube for a nuclear reactor using the tubular body according to any one of claims 1 to 9. Combining a first end plug with the first end of the mandrel, inserting a second end plug having a through-hole into the second end of the mandrel, and preparing a mandrel assembly; and
A braiding step of weaving ceramic fibers on the surface of the mandrel assembly to form a braided body;
A matrix forming step of forming a cylindrical member by forming a ceramic matrix between ceramic fibers of the braided body;
And a mandrel extraction step for extracting the mandrel from the cylindrical member leaving the first end plug and the second end plug.
The tubular member has a narrowed portion along an outer surface of the first end plug and / or the second end plug.   The method for producing a tubular body according to claim 11, wherein the first end plug and / or the second end plug have a tapered surface along a narrowed portion of the cylindrical member. 13. The first end plug and / or the second end plug are made of any one of SiC, Ti ₃ SiC ₂ , Mo, W, Zircaloy, or FeCrAl. A method for manufacturing a tubular body.   The said ceramic fiber is a SiC fiber, The manufacturing method of the tubular body as described in any one of Claims 11-13 characterized by the above-mentioned.   The said ceramic matrix is SiC, The manufacturing method of the tubular body as described in any one of Claims 11-14 characterized by the above-mentioned.   The method for manufacturing a tubular body according to any one of claims 11 to 15, wherein the first end plug has a cylindrical shape in which an opening end side of the cylindrical member is chamfered. The said 2nd end plug is a barrel shape which has the taper surface on both sides and the center part expanded, The manufacturing of the tubular body as described in any one of Claims 11-15 characterized by the above-mentioned. Method.   18. The tubular member according to claim 17, wherein the second end plug has an edge where an inner surface of the through hole and a taper surface on a central side of the tubular member are in contact, and the tubular member is in contact with the edge. Body manufacturing method.   The method for manufacturing a tubular body according to claim 18, wherein a third end plug is further inserted into the through hole.   The manufacturing method of the cladding tube for nuclear reactors using the tubular body as described in any one of Claims 11-19.