JP6209110B2 - Radioactive material storage container - Google Patents

Description

  The present invention relates to a radioactive substance storage container that stores a radioactive substance therein.

  Spent fuel used in the nuclear power plant is temporarily stored in a spent fuel storage pool in the nuclear power plant and cooled. Spent fuel cooled in the spent fuel storage pool is transported to a reprocessing facility. However, since there is a limit to the amount of storage in the spent fuel storage pool, spent fuel may be stored in a radioactive substance storage container (cask). In some cases, spent fuel is stored in a cask and transported to a reprocessing facility.

  Generally, a cask has a cylindrical trunk body that stores spent fuel, and an outer cylinder that is provided on the outer periphery of the container. In addition, a heat transfer fin is provided between the trunk body and the outer cylinder to release the heat of the spent fuel to the outside. For example, as described in Patent Document 1, the heat transfer fins are welded to the trunk body and the outer cylinder, respectively.

JP-A-4-36697

  Nowadays, a cask that stores spent fuel is required to maintain its soundness even in the event of a fire.

  An object of this invention is to provide the radioactive substance storage container which suppresses the heat transfer from the outside to the inside, in order to ensure the soundness with respect to a fire.

  In order to solve the above-described problems and achieve the object, the radioactive substance storage container of the present invention is a cylindrical member, and a trunk body in which a plurality of first groove portions are provided in the circumferential direction at predetermined intervals in the outer circumferential portion. A plurality of second groove portions in the inner peripheral portion with a predetermined interval in the circumferential direction, and an outer cylinder provided at a predetermined distance away from the outer peripheral portion of the trunk body, and a first end portion in the in-plane direction. One end portion is fitted into the first groove portion, and the second end portion, which is the other end portion, is fitted into the second groove portion, whereby the in-plane direction is a direction perpendicular to the axis of the trunk body. And a heat transfer fin that is provided on the trunk body and the outer cylinder so as to be along a direction inclined with respect to the inner surface and is deformable in the in-plane direction.

  In this radioactive substance storage container, the heat transfer fins can be deformed in the in-plane direction. Therefore, when the outer cylinder is thermally expanded by heat from the outside and moves outward in the radial direction, the adhesion between the heat transfer fin and the outer cylinder or the adhesion between the heat transfer fin and the trunk body is released. Therefore, this radioactive substance storage container reduces the thermal conductivity from the outer cylinder to the trunk body. That is, this radioactive substance storage container can suppress heat transfer from the outside to the inside.

  In the radioactive substance storage container, it is preferable that a space is provided between the second groove portion and the second end portion. Since this radioactive substance storage container has a space between the groove and the heat transfer fin, heat transfer from the outside to the inside can be more suitably suppressed.

  In the radioactive substance storage container, it is preferable that a heat transfer medium is provided in the space. Since the radioactive substance storage container is provided with a heat transfer medium in the space, the decay heat of the radioactive substance inside the radioactive substance storage container can be efficiently released to the outside.

  In the radioactive substance storage container, the heat transfer fin has one of the first groove, the first end, the second groove, and the second end fixed to each other. The other is preferably supported so as to be movable relative to each other. In this radioactive substance storage container, since one of the heat transfer fins is fixed to the groove portion, the work load at the time of assembly can be reduced.

  In the radioactive substance storage container, the heat transfer fin is welded at any one of the first groove portion, the first end portion, the second groove portion, and the second end portion. It is preferable. In this radioactive substance storage container, since one of the heat transfer fins is fixed to the groove portion, the work load at the time of assembly can be reduced.

  In the radioactive substance storage container, a connecting member that melts when the temperature reaches a predetermined temperature or more is fixed to the first groove portion or the second groove portion, and the heat transfer fin includes the connecting member. It is preferable that the first groove portion or the second groove portion is fitted to the first groove portion or the second groove portion. Since this radioactive substance storage container has a connecting member, heat transfer from the outside to the inside can be more suitably suppressed.

  According to the present invention, heat transfer from the outside to the inside of the radioactive substance storage container can be suppressed.

FIG. 1 is a longitudinal sectional view of a cask according to the first embodiment. FIG. 2 is a plan sectional view of the cask according to the first embodiment. FIG. 3 is a cross-sectional view of a main part of the cask according to the first embodiment. FIG. 4 is a cross-sectional view of a main part of the cask according to the second embodiment. FIG. 5 is a cross-sectional view of a main part of the cask according to the third embodiment. FIG. 6 is a cross-sectional view of a main part of the cask according to the fourth embodiment. FIG. 7 is a cross-sectional view of a main part of the cask according to the fifth embodiment.

(Embodiment 1)
Embodiment 1 will be described in detail with reference to the drawings. 1 is a longitudinal sectional view of a cask according to the first embodiment, and FIG. 2 is a plan sectional view of the cask according to the first embodiment.

  A cask 11 as a radioactive substance storage container includes a body portion 12, a lid portion 13, and a basket 14. The trunk portion 12 is a cylindrical member, and has a cylindrical shape in which an opening 22 is formed on one side of the trunk body 21, that is, an upper portion, and a bottom portion (blocking portion) 23 is formed on the other side, that is, a lower portion. In addition, a radioactive substance (for example, a spent fuel assembly) can be stored inside. That is, the trunk body 21 is provided with a cavity 24 inside, and the cavity 24 has a shape matching the outer peripheral shape of the basket 14. The basket 14 has a plurality of cells that individually store a plurality of radioactive substances (not shown). The basket 14 has a basket body 14A as shown in FIG. In the basket body 14A, radioactive substance storage portions 14B as cells arranged parallel to each other at a predetermined interval are formed continuously in the vertical direction. The vertical direction is a direction along the cylindrical axial direction X of the trunk body 21 in the cask 11 and corresponds to the vertical direction of the trunk body 21. And the bottom part 23 of the trunk | drum main body 21 is couple | bonded or integrally molded by welding, and this trunk | drum main body 21 and the bottom part 23 are forged products made from carbon steel which has a gamma ray shielding function. The trunk body 21 and the bottom 23 can be made of stainless steel instead of carbon steel. The trunk body 21 and the bottom portion 23 can also be made of cast products such as spheroidal graphite cast iron or carbon steel cast steel.

  The body portion 12 is provided with an outer cylinder 25 on the outer peripheral side of the body body 21 at a predetermined distance. The outer cylinder 25 is manufactured by carbon steel etc., for example. As shown in FIG. 2, a plurality of heat transfer fins 40 are provided at predetermined intervals in the circumferential direction between the outer peripheral surface of the trunk body 21 and the inner peripheral surface of the outer cylinder 25. The body 12 is a resin (neutron shielding body) 26 containing boron or a boron compound which is a polymer material containing a large amount of hydrogen and has a neutron shielding function in the space between the body body 21 and the outer cylinder 25. However, it is injected and solidified in a fluidized state via a pipe or the like (not shown). Details of the heat transfer fin 40 will be described later.

  The body portion 12 may have a bottom plate 28 connected to the lower side of the bottom portion 23 by a plurality of connecting plates 27 with a predetermined gap, and a resin (neutron shield) is formed in a space between the connecting plate 27 and the bottom plate 28. ) 29 is provided. Moreover, the trunnion 30 is being fixed to the side surface of the trunk | drum 12. As shown in FIG. The connecting plate 27 may not be provided.

  The lid 13 that closes the opening 22 of the trunk body 21 in the trunk 12 includes a primary lid 31 and a secondary lid 32. The primary lid portion 31 is a disk-shaped member made of stainless steel or carbon steel that shields γ rays. The secondary lid 32 is also a disk-shaped member made of stainless steel or carbon steel, and a resin (neutron shield) 33 is enclosed therein. The primary lid portion 31 and the secondary lid portion 32 are detachably attached to the upper end portion of the trunk body 21 with stainless steel or carbon steel bolts (not shown). In this case, metal gaskets (not shown) are interposed between the primary lid portion 31 and the secondary lid portion 32 and the trunk body 21 to ensure the internal sealing performance. The resin 33 may be provided on the primary lid 31 or may be provided only on the primary lid 31. In addition, an auxiliary shield 34 enclosing a resin may be provided around the lid portion 13. Next, the heat transfer fin 40 will be described.

  FIG. 3 is a cross-sectional view of a main part of the cask according to the first embodiment. The heat transfer fins 40 are plate-shaped members that are made of a material having high thermal conductivity and a higher coefficient of thermal expansion than the trunk body 21 and the outer cylinder 25. For example, the heat transfer fin 40 is made of copper or the like.

  As shown in FIGS. 2 and 3, a plurality of first groove portions 51 are provided at predetermined intervals in the circumferential direction on the outer peripheral portion of the trunk body 21. Although described later in detail, the heat transfer fin 40 is attached to the first groove 51. The first groove portion 51 extends along the axial direction X, and is inclined with respect to the direction perpendicular to the axial direction with respect to the axial direction X. That is, the first groove 51 is provided to be inclined with respect to the radial direction A of the trunk body 21. The radial direction A is a direction from the central axis O toward the radially outer side of the trunk body 21. The first groove portion 51 has a bottom portion 53 and both side portions 54. Although the 1st groove part 51 is U-shaped which has the bottom part 53 and the both-sides part 54, it is not restricted to this. As long as the heat transfer fin 40 can be attached, the 1st groove part 51 may be arbitrary shapes, such as a U-shape and a V-shape, for example.

  A plurality of second groove portions 52 are provided on the inner peripheral portion of the outer cylinder 25 at predetermined intervals in the circumferential direction. Although described later in detail, the heat transfer fin 40 is attached to the second groove portion 52. The second groove 52 extends along the axial direction X, and is inclined with respect to a direction perpendicular to the axial direction with respect to the axial direction X. That is, the second groove portion 52 is provided to be inclined with respect to the radial direction A of the trunk body 21. The second groove portion 52 has a bottom portion 55 and both side portions 56. The second groove portion 52 has a U-shape having a bottom portion 55 and both side portions 56, but is not limited thereto. As long as the heat transfer fin 40 can be attached, the 2nd groove part 52 may be arbitrary shapes, such as a U shape or a V shape, for example.

  The central axis B of the first groove 51 and the central axis C of the second groove 52 may be provided so as to coincide with each other (including tolerance). When the central axis B and the central axis C coincide with each other, the backlash between the first groove 51 and the second groove 52 can be reduced, and the heat transfer fins 40 that are plate-like members can be easily attached. it can.

  The heat transfer fin 40 has a first end 41 that is one end in the in-plane direction Y and a second end 42 that is the other end. The first end portion 41 is fitted into the first groove portion 51, and the second end portion 42 is fitted into the second groove portion 52. The in-plane direction Y is a direction along the surface 47 of the heat transfer fin 40. The in-plane direction Y is a direction connecting the first groove portion 51 and the second groove portion 52. Therefore, the in-plane direction Y is a direction inclined with respect to a direction perpendicular to the axis direction X of the trunk body 21. In other words, the in-plane direction Y is a direction inclined with respect to the radial direction A of the trunk body 21. The first end portion 41, the first groove portion 51, the second end portion 42, and the second groove portion 52 are movably fitted to each other. The first end 41 and the first groove 51, and the second end 42 and the second groove 52 are attached by, for example, a clearance fit. As will be described later in detail, the heat transfer fin 40 can be deformed in the in-plane direction Y with respect to the first groove 51 and the second groove 52.

  When the radioactive substance is stored inside the trunk body 21, the decay heat of the radioactive substance is transferred to the trunk body 21. The heat of the trunk body 21 is transferred to the heat transfer fins 40 via the first groove portion 51 and the first end portion 41. The heat transferred to the heat transfer fins 40 is transferred to the outer cylinder 25 via the second end portion 42 and the second groove portion 52 and is radiated to the outside. By this heat transfer, the trunk body 21, the heat transfer fins 40, and the outer cylinder 25 are thermally expanded.

  When the body main body 21 is thermally expanded, the body main body 21 expands in a direction in which the diameter increases. Accordingly, the bottom 53 moves toward the outer periphery of the trunk body 21 along the central axis B. Further, the widths of the side portions 54 are increased. Similarly, when the outer cylinder 25 is thermally expanded, it expands in a direction in which the diameter increases. Accordingly, the bottom 55 moves toward the outer periphery of the trunk body 21 along the central axis C. The widths of the both side portions 56 are increased. When the heat transfer fin 40 is thermally expanded, the heat transfer fin 40 expands in the in-plane direction Y and the perpendicular direction Z that is a direction perpendicular to the in-plane direction Y. Therefore, the end surface 43 of the first end portion 41 moves toward the center of the trunk body 21 along the in-plane direction Y. Further, the widths of both side surfaces 44 of the first end portion 41 are increased. Similarly, the end surface 45 of the second end portion 42 moves toward the outer periphery of the trunk body 21 along the in-plane direction Y. Further, the widths of both side surfaces 46 of the second end portion 42 are increased. In other words, the heat transfer fin 40 can be deformed in the in-plane direction Y and the perpendicular direction Z with respect to the first groove 51 and the second groove 52 by thermal expansion.

  The heat transfer fin 40 has a larger coefficient of thermal expansion than the trunk body 21 and the outer cylinder 25. Therefore, when the thermal expansion is caused by the decay heat of the radioactive substance, the length of the heat transfer fin 40 is larger than the distance between the first groove 51 and the second groove 52 (the length from the bottom 53 to the bottom 55). (The length along the in-plane direction Y from the end face 43 to the end face 45) is larger. Accordingly, the heat transfer fin 40 is fixed with the first end 41 in close contact with the first groove 51 and the second end 42 in close contact with the second groove 52. Further, the width of the heat transfer fin 40 (the perpendicular direction Z of the side surfaces 44 and the side surfaces 46) is larger than the width of the first groove portion 51 and the width of the second groove portion 52 (widths of the side portions 54 and the side portions 56). The width along () may be larger. In this case, the heat transfer fin 40 can be in close contact with the first groove 51 and the second groove 52 even in the perpendicular direction Z. In this way, the heat transfer fins 40 are in close contact with the outer cylinder 25 and the trunk body 21 by deformation due to thermal expansion.

  For example, when there is a fire or the like around the cask 11, the cask 11 is heated from the outside. In this case, external heat is transmitted to the outer cylinder 25. The heat of the outer cylinder 25 is transmitted to the heat transfer fins 40 through the second groove portion 52 and the second end portion 42. The heat transferred to the heat transfer fins 40 is transferred to the trunk body 21 and the inside thereof via the first end 41 and the first groove 51.

  When the cask 11 is heated from the outside due to a fire or the like, the temperature of the outer cylinder 25 becomes higher than that of the heat transfer fins 40, so that the outer cylinder 25 greatly expands before the heat transfer fins 40. Therefore, the distance between the first groove 51 and the second groove 52 is larger than the length of the heat transfer fin 40. Further, the width of the heat transfer fin 40 is larger than the width of the second groove portion 52. That is, the close contact between the second end portion 42 and the second groove portion 52 is released. In this case, it can be said that the heat transfer fin 40 can be deformed in the in-plane direction Y and the in-plane direction Z with respect to the second groove 52 by thermal expansion. In this case, since the heat transfer fins 40 are more thermally expanded than the trunk body 21, the close contact between the first end 41 and the first groove 51 is not released.

  As described above, when the cask 11 is heated from the outside due to a fire or the like, the outer cylinder 25 expands in the outer circumferential direction, so that the close contact between the second end portion 42 and the second groove portion 52 is released. When the close contact between the second end portion 42 and the second groove portion 52 is released, the thermal conductivity between the outer cylinder 25 and the heat transfer fin 40 is lowered. That is, heat transfer from the outer cylinder 25 to the heat transfer fins 40 and the trunk body 21 is suppressed. Therefore, when the cask 11 is heated from the outside due to a fire or the like, the cask 11 according to the first embodiment can suppress heat transfer from the outside to the inside.

  Further, the heat transfer fin 40 is deformed in the in-plane direction Y with respect to the first groove portion 51 and the second groove portion 52 by decay heat of the radioactive substance stored inside the trunk body 21. The heat transfer fins 40 are in close contact with the first groove 51 and the second groove 52. When the heat transfer fin 40 and the first groove 51 and the second groove 52 are in close contact with each other, the thermal conductivity between the heat transfer fin 40 and the trunk body 21 and the outer cylinder 25 is improved. That is, the heat transfer fins 40 can suitably transfer heat from the trunk body 21 to the outer cylinder 25. Therefore, the cask 11 according to Embodiment 1 can suitably release the heat of the radioactive material inside to the outside.

  Moreover, when attaching a heat-transfer fin, a trunk | drum main body, and an outer cylinder, welding may be performed, but the work load with respect to attachment may become high for the following reasons. That is, since the heat transfer fin and the trunk body and the outer cylinder are made of different materials, the weldability is low and the cask is enormous, which may increase the work load for installation. However, the cask 11 according to the first embodiment attaches the heat transfer fin 40 to the trunk body 21 and the outer cylinder 25 by fitting the heat transfer fin 40 into the first groove portion 51 and the second groove portion 52. . And the heat-transfer fin 40 is fixed to the 1st groove part 51 and the 2nd groove part 52 by the thermal expansion resulting from the decay heat of a radioactive substance. Therefore, the cask 11 according to the first embodiment can reduce the work load when the heat transfer fins 40, the trunk body 21, and the outer cylinder 25 are attached.

  Further, the heat transfer fin 40 is attached along the direction in which the in-plane direction Y is inclined with respect to the direction perpendicular to the axial direction X of the trunk body 21 and is inclined with respect to the radial direction A. Yes. Neutrons are emitted in the radial direction of the trunk body 21. By providing the heat transfer fins 40 so as to be inclined with respect to the radial direction of the trunk main body 21, the resin 26 can surround the circumference of the trunk main body 21 without leakage, and the neutron shielding performance of the resin 26 can sufficiently function.

(Embodiment 2)
The second embodiment will be described in detail with reference to the drawings. FIG. 4 is a cross-sectional view of a main part of the cask according to the second embodiment. The cask 11a according to the second embodiment has a space 60 between the heat transfer fins 40a and the second groove 52a. In addition, description is abbreviate | omitted about the structure which is common in Embodiment 1. FIG.

  As shown in FIG. 4, a second groove 52a is provided on the inner periphery of the outer cylinder 25a. The second groove portion 52a has a bottom portion 55a and both side portions 56a. The heat transfer fin 40a has a first end 41a that is one end in the in-plane direction Y and a second end 42a that is the other end. The first end 41a is fitted into the first groove 51, and the second end 42a is fitted into the second groove 52a. The second end portion 42a has an end face 45a and both side faces 46a. A space 60 is provided between the second end portion 42a and the second groove portion 52a, that is, between the end surface 45a and the bottom portion 55a. That is, the end face 45a and the bottom 55a are separated from each other by a predetermined distance.

  When the cask 11a is heated from the outside due to a fire or the like, the temperature of the outer cylinder 25a becomes higher than that of the heat transfer fins 40a, so that the outer cylinder 25a greatly expands before the heat transfer fins 40a. That is, the heat transfer fin 40a is deformed in the direction of increasing the distance between the end face 45a and the bottom 55a. The end face 45a and the bottom 55a are separated from each other by a predetermined distance, and the distance is further increased, so that the fitting between the second end 42a and the second groove 52a is released. In other words, when the cask 11a is heated from the outside due to a fire or the like, the heat transfer fin 40a is detached from the second groove portion 52a.

  As described above, since the space 60 is provided between the second end portion 42a and the second groove portion 52a, when the cask 11a is heated from the outside due to a fire or the like, the heat transfer fin 40a is It comes off from the second groove 52a. When the heat transfer fin 40a is detached from the second groove 52a, heat transfer from the outer cylinder 25a to the heat transfer fin 40a and the body main body 21 is more preferably suppressed. Therefore, when the cask 11a is heated from the outside due to a fire or the like, the cask 11a according to the second embodiment can more suitably suppress heat transfer from the outside to the inside.

  A heat transfer medium may be provided in the space 60. The heat transfer medium is manufactured from a material having high thermal conductivity. The material of the heat transfer medium is arbitrary, but a paste-like heat transfer medium may be applied to the second groove 52a or the second end 42a. As the paste-like heat transfer medium, for example, heat conductive grease, heat transfer cement, metal paste, or carbon paste is preferable, but not limited thereto. By providing the heat transfer medium in the space 60, the decay heat of the radioactive material stored inside the trunk body 21 can be more suitably released.

(Embodiment 3)
Next, Embodiment 3 will be described in detail with reference to the drawings. FIG. 5 is a cross-sectional view of a main part of the cask according to the third embodiment. In the cask 11b according to the third embodiment, the heat transfer fin 40b and the first groove 51b are fixed. The description of the configuration common to the first embodiment is omitted.

  As shown in FIG. 5, a first groove 51b is provided on the outer periphery of the trunk body 21b. The first groove portion 51b has a bottom portion 53b and both side portions 54b. Both side portions 54b have a width that decreases in the direction opposite to the bottom portion 53b. That is, the first groove 51b has a trapezoidal cross section when viewed from the axial direction X. The first groove 51b is not limited to a trapezoidal shape as long as at least a part of the width of both side parts 54b is larger than the width of the first groove 51b on the outer periphery of the trunk body 21b.

  The heat transfer fin 40b has a first end portion 41b that is one end portion in the in-plane direction Y, and a second end portion 42b that is the other end portion. The second end portion 42b is movably fitted (supported) in the second groove portion 52. The first end portion 41b has an end surface 43b and both side surfaces 44b. Both side surfaces 44b have a width that decreases in the direction opposite to the end surface 43b. That is, the first end portion 41b has a trapezoidal shape as viewed from the axial direction X. The first end portion 41b is not limited to a trapezoidal shape as long as at least a part of the width of both side surfaces 44b is larger than the width of the heat transfer fin 40b.

  The first end portions 41b are attached to the first groove portions 51b and are fixed to each other. That is, the first end portion 41b and the first groove portion 51b are reduced in width in the direction opposite to the end face 43b and in the direction opposite to the bottom portion 53b, respectively. For example, it is fixed along the in-plane direction Y with respect to the first groove 51b. The heat transfer fins 40b are attached to the trunk body 21b while being slid along the axial direction X, for example. Thus, the first end portions 41b are fixed to each other with the first groove portion 51b as a key groove. The first end 41b and the first groove 51b may have any shape as long as they are fixed along the in-plane direction Y. For example, the first end portion 41b and the first groove portion 51b may have a bowl shape. Further, for example, the first end portion 41b and the first groove portion 51b may be fixed to each other by fitting (fitting fit).

  The heat transfer fin 40 b is movable in the in-plane direction Y with respect to the second groove portion 52. Therefore, when the cask 11b is heated from the outside due to a fire or the like, heat transfer from the outer cylinder 25 to the heat transfer fins 40b is suppressed. Therefore, the cask 11b according to Embodiment 3 can more suitably suppress heat transfer from the outside to the inside.

  The heat transfer fin 40b is fixed to the first groove 51b. Therefore, when attaching the outer cylinder 25 at the time of assembling the cask 11b, the heat transfer fins 40b can be further stabilized. Therefore, the cask 11b according to the third embodiment can reduce the work load during assembly. Further, the heat transfer fins 40b and the first groove 51b are fixed without performing welding. Therefore, the cask 11b can reduce the work load at the time of assembly. However, the heat transfer fin 40b and the first groove 51b may be fixed by welding.

  As in the second embodiment, a space may be provided between the second end portion 42 b and the second groove portion 52. Further, the first end 41b and the first groove 51b may be movably fitted, and the second end 42b and the second groove 52 may be fixed to each other. Even in this case, when the cask 11b is heated from the outside due to a fire or the like, heat transfer from the heat transfer fins 40b to the trunk body 21 is suppressed. Therefore, the cask 11b according to Embodiment 3 can more suitably suppress heat transfer from the outside to the inside. In this case, a space may be provided between the first end portion 41b and the first groove portion 51b.

(Embodiment 4)
Next, Embodiment 4 will be described in detail with reference to the drawings. FIG. 6 is a cross-sectional view of a main part of the cask according to the fourth embodiment. The cask 11c according to the fourth embodiment includes a first heat transfer fin 61 and a second heat transfer fin 62 that are movably connected to each other. In addition, description is abbreviate | omitted about the structure which is common in Embodiment 1. FIG.

  As shown in FIG. 6, a first groove 51c is provided on the outer periphery of the trunk body 21c. The first groove 51c has the same shape as the first groove 51b according to the third embodiment. For example, the cross section viewed from the axial direction X has a trapezoidal shape. A second groove 52c is provided on the inner peripheral portion of the outer cylinder 25c. The second groove part 52c also has the same shape as the first groove part 51b according to the third embodiment. For example, the cross section viewed from the axial direction X has a trapezoidal shape.

  The cask 11 c has first heat transfer fins 61 and second heat transfer fins 62. One of the first heat transfer fins 61 along the in-plane direction Y is the first end portion 41 c and the other is the end portion 63. The first end 41c has the same shape as the first end 41b according to the third embodiment. For example, the cross section viewed from the axial direction X has a trapezoidal shape. The first end 41c is attached and fixed to the first groove 51c.

  In the second heat transfer fin 62, one end portion along the in-plane direction Y is the second end portion 42c, and the other end portion has a groove-like connection portion 64. The second end portion 42c has the same shape as the first end portion 41b according to the third embodiment. For example, the cross section viewed from the axial direction X has a trapezoidal shape. The second end portion 42c is attached and fixed to the second groove portion 52c.

  The first heat transfer fin 61 and the second heat transfer fin 62 are connected to each other by an end portion 63 and a connection portion 64. More specifically, the end portions 63 are movably fitted to the groove-like connecting portion 64. Accordingly, the first heat transfer fins 61 can be deformed along the in-plane direction Y with respect to the second groove 52c. Further, the second heat transfer fin 62 can be deformed along the in-plane direction Y with respect to the first groove 51c. Further, the end portion 63 and the connecting portion 64 are in close contact with each other due to decay heat of the radioactive substance inside the trunk body 21c.

  As described above, the second heat transfer fins 62 are fixed to the outer cylinder 25c. Therefore, when the cask 11c is heated from the outside due to a fire or the like, the second heat transfer fins 62 move along the in-plane direction Y toward the outer periphery of the trunk body 21c together with the thermally expanded outer cylinder 25c. On the other hand, the first heat transfer fins 61 do not move with the thermal expansion of the outer cylinder 25c. Accordingly, the close contact between the end portion 63 and the connecting portion 64 is released. When the close contact between the end portion 63 and the connecting portion 64 is released, the heat transfer performance from the second heat transfer fin 62 to the first heat transfer fin 61 decreases. Therefore, the cask 11c according to the fourth embodiment can suppress heat transfer from the outside to the inside when the cask 11c is heated from the outside due to a fire or the like. Further, in this case, the second heat transfer fins 62 have a higher temperature than the first heat transfer fins 61, and therefore, the second heat transfer fins 62 expand more thermally than the first heat transfer fins 61. Therefore, the groove width of the connecting portion 64 is larger than the width of the end portion 63. Accordingly, the cask 11c can more suitably suppress heat transfer from the outside to the inside. Further, a space may be provided between the end portion 63 and the connecting portion 64.

  The first heat transfer fin 61 is fixed to the first groove 51c, and the second heat transfer fin 62 is fixed to the second groove 52c. Accordingly, since the first heat transfer fins 61 and the second heat transfer fins 62 can be stabilized at the time of assembling the cask 11c, the work load at the time of assembling can be reduced. Further, the first heat transfer fin 61 and the first groove 51c, the second heat transfer fin 62 and the second groove 52c are fixed without being welded. Therefore, the cask 11c can reduce the work load at the time of assembly. However, the first heat transfer fin 61 and the first groove portion 51c, and the second heat transfer fin 62 and the second groove portion 52c may be fixed by, for example, fitting (fitting) or welding. .

  In addition, the connection part 64 is not restricted to groove shape, If the edge part 63 and the connection part 64 are connected so that a movement is mutually possible, the shape of the connection part 64 will be selected arbitrarily. Further, the connecting portion may be provided in the first heat transfer fin 61.

(Embodiment 5)
Next, Embodiment 5 will be described in detail with reference to the drawings. FIG. 7 is a cross-sectional view of a main part of the cask according to the fifth embodiment. The cask 11d according to the fifth embodiment is different from the cask 11 according to the first embodiment in that it includes a connecting member 66. In addition, description is abbreviate | omitted about the structure which is common in Embodiment 1. FIG.

  As shown in FIG. 7, a first groove 51d is provided on the outer periphery of the trunk body 21d. The first groove 51d has the same shape as the first groove 51b according to the third embodiment. For example, the cross section viewed from the axial direction X has a trapezoidal shape. A second groove 52d is provided on the inner peripheral portion of the outer cylinder 25d. The second groove portion 52d also has the same shape as the first groove portion 51b according to the third embodiment. For example, the cross section viewed from the axial direction X has a trapezoidal shape.

  The cask 11d has a heat transfer fin 40d and a connecting member 66. The heat transfer fin 40d has a first end 41d that is one end in the in-plane direction Y and a second end 42d that is the other end. The first end 41d has the same shape as the first end 41b according to the third embodiment. For example, the cross section viewed from the axial direction X has a trapezoidal shape. The second end 42d has, for example, a groove shape.

  The connecting member 66 is made of a material that melts when the temperature exceeds a predetermined temperature. The connecting member 66 is made of a material having a melting point lower than that of the trunk body 21d, the outer cylinder 25d, and the heat transfer fins 40d, and is not melted by the decay heat of the radioactive substance housed inside the trunk body 21d. . The connecting member 66 is made of, for example, lead or tin. The connecting member 66 has an end 67 at one end in the in-plane direction Y, and a fixing portion 68 at the other end. The fixing portion 68 has the same shape as that of the first end portion 41b according to the third embodiment. For example, the cross section viewed from the axial direction X has a trapezoidal shape.

  The first end 41d is attached and fixed to the first groove 51d. The first end 41d and the first groove 51d may be fixed by, for example, fitting (seam fitting) or welding. Note that the first end 41d and the first groove 51d may be movably fitted.

  The second end portion 42d and the end portion 67 are movably fitted to each other. The fixing portion 68 is attached and fixed to the second groove portion 52d. In other words, the second end portion 42 d is movably fitted to the second groove portion 52 d via the connecting member 66. Here, the second end portion 42d has a groove shape, but the end portion 67 may have a groove shape. Moreover, the fixing | fixed part 68 and the 2nd groove part 52d may be fixed, for example by mutually fitting (seam fitting).

  When the cask 11d is heated from the outside due to a fire or the like, the connecting member 66 fixed to the outer cylinder 25d is melted. For this reason, the heat transfer fins 40d fitted into the second groove 52d via the connecting member 66 are removed from the second groove 52d. Therefore, in the cask 11d according to the fifth embodiment, when the cask 11d is heated from the outside due to a fire or the like, the connection member 66 is melted, so that heat transfer from the outside to the inside can be more suitably suppressed.

  The connecting member 66 may be fixed to the first groove 51d. Also in this case, when the cask 11d is heated from the outside due to a fire or the like, heat from the outside is transmitted to the connecting member 66 through the outer cylinder 25d and the heat transfer fins 40d, and the connecting member 66 is melted.

  As mentioned above, although embodiment of this invention was described, these embodiment is not limited by the content of these embodiment. In addition, the above-described constituent elements include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range. Furthermore, the above-described components can be appropriately combined. Furthermore, various omissions, substitutions, or changes of the constituent elements can be made without departing from the spirit of the above-described embodiments and the like.

DESCRIPTION OF SYMBOLS 11 Cask 12 trunk | drum 13 lid | cover part 21 trunk | drum 22 opening part 23 bottom part 25 outer cylinder 26 resin 40 heat-transfer fin 41 1st edge part 42 2nd edge part 51 1st groove part 52 2nd groove part X Axial direction Y in-plane direction Z-plane perpendicular direction

Claims (6)

A cylindrical member, and a trunk body provided with a plurality of first groove portions at a predetermined interval in a circumferential direction on an outer peripheral portion;
A plurality of second groove portions provided at a predetermined interval in the circumferential direction on the inner peripheral portion and an outer cylinder provided at a predetermined distance away from the outer peripheral portion of the trunk body;
A first end that is one end in a radial direction that is a direction from the central axis of the trunk body toward the radially outer side is fitted into the first groove and a second end that is the other end. by but it fits in the second groove, provided in the cylinder body and the outer cylinder along the direction in which the surface is inclined in the circumferential direction of orientation of the trunk body to the radiation direction of the trunk body And heat transfer fins that are deformable in a direction along the surface ;
A radioactive substance storage container. A space is provided between the second groove and the second end.
The radioactive substance storage container according to claim 1. The radioactive substance storage container according to claim 2, wherein a heat transfer medium is provided in the space. The heat transfer fin has one of the first groove, the first end, the second groove, and the second end fixed to each other, and the other supported to be movable with respect to each other. To be
The radioactive substance storage container according to any one of claims 1 to 3. The heat transfer fin is welded at any one of the first groove, the first end, the second groove, and the second end.
The radioactive substance storage container according to claim 4. In the first groove portion or the second groove portion, a connecting member that melts when a predetermined temperature or higher is fixed,
The heat transfer fin is fitted into the first groove portion or the second groove portion via the connecting member.
The radioactive substance storage container according to claim 1.

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