JP2018155583A - Reactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reactor capable of easily providing a structure which can suppress jumping up of a core component by vertical vibrations.SOLUTION: A reactor includes: a core component 14 having a support structure having a plurality of connecting tubes arranged inside a reactor vessel and a support plate 12 for supporting the connecting tubes, entrance nozzles 16 inserted into the connecting tubes and a fuel rod main body 17 upper than the entrance nozzles 16; and a nozzle side stepped part 18 located between the entrance nozzle 16 and the fuel rod main boy 17 and abutting against the connecting tubes from above. The core component 14 includes: a storage part 40 provided on the nozzle side step part 18 and opened by facing the connecting tubes; and an advance/retreat part 41 stored while being protrusible downward in the storage part 40 and sinking while generating a damping force by abutting against the connecting tubes from above.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a nuclear reactor.

  In a nuclear power generation facility, power is generated by driving a turbine using heat from a fission reaction that proceeds in a core. Core components such as a nuclear fuel rod in which nuclear fuel is sealed and a control rod for controlling the progress of the fission reaction are stored inside the core.

  An entrance nozzle is formed at the end of the core component. By inserting the entrance nozzle into the connecting pipe, the core components are supported in a self-supporting state. Therefore, if vertical vibrations are applied to the core components when an earthquake occurs, they will jump upward from the core component connecting pipe. In this case, the core components can be dissipated in the core, which can hinder the insertion of control rods in particular.

  As a technique for suppressing the jumping of the core components as described above, a technique having a dash pod structure described in Patent Document 1 is known. In the nuclear reactor described in Patent Document 1, a space as a dash pod portion is formed by the stepped portion formed on the fitting surface of the entrance nozzle and the stepped portion formed on the fitting surface of the connecting pipe. . As a result, even when a force that causes a jump to the core component is applied, the force that prevents the volume change of the fluid (liquid) filled in the dash pod acts as a damping force, so that the core component It is said that it is possible to suppress jumping up.

JP 2013-117500 A

However, in the conventional nuclear reactor in which the dash pod structure is provided in order to suppress the jumping of the core component, the dash pod structure is formed between the fitting surface of the connecting pipe and the fitting surface of the core component. Yes. That is, a rising portion is provided on the upper end side of the connecting pipe to form the fitting surface in a specific shape, and the fitting surface on the entrance nozzle side in the core component is formed in a specific shape so that the relative shape of both is appropriately By setting, a dash pod structure is formed.
For this reason, there are restrictions on the shapes of the connecting pipe and the core components, and it is difficult to provide a structure for suppressing the jumping of the core components, especially to suppress the jumping of the core components in the existing nuclear reactor. There was a problem that it was not easy to add the structure.

  The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a nuclear reactor capable of easily providing a structure capable of suppressing the jumping of core components due to vertical vibration. .

  According to the first aspect of the present invention, the nuclear reactor includes a nuclear reactor vessel that is filled with a liquid and a reactor vessel that is provided in the nuclear reactor vessel and has a cylindrical shape that extends in the vertical direction and is arranged in a plurality in the horizontal direction. And a support structure having a support plate that supports the connection pipe and extends in the horizontal direction, a small diameter portion that is inserted into the connection pipe, a large diameter portion that is located above the small diameter portion, and A core component having a shape change portion that is positioned between the small diameter portion and the large diameter portion and is supported by being in contact with the connecting pipe from above, and the core component is the shape change portion A housing portion that is open to face the connecting pipe, and is housed in the housing portion so as to be able to project and retract downward, and is brought into contact with the connecting pipe from above to sink while generating a damping force. And a retreating part.

  According to the present invention, the advancing / retreating part accommodated in the accommodating part so as to be able to project and retract is configured to sunk while generating a damping force by coming into contact with the connecting pipe from above. Therefore, when the core components are displaced upward from the support structure and the advance / retreat part protrudes downward from the shape change part, the advance / retreat part sinks and attenuates kinetic energy when it is displaced downward again and contacts the support structure. it can. Thereby, even if the vertical vibration is applied to the core component, it is possible to suppress the core component from jumping up from the support structure.

  And since the accommodating part and the advancing / retreating part are provided in the core component, it is not necessary to provide a structure for suppressing the jump of the core component in the connecting pipe of the support structure, and the degree of freedom of the structure of the connecting pipe is large. . For example, it is also possible to realize a structure for suppressing the jumping up of the core components by using the existing reactor support structure and connecting pipe as they are.

  According to a second aspect of the present invention, in the first aspect, in the core component, a storage part whose volume is increased or decreased by the advance / retreat of the advance / retreat part, and a resistance that causes the liquid to flow into and out of the storage part. An attenuation portion having a flow path may be provided in the housing portion.

  According to this configuration, since the attenuation portion having the storage portion whose volume is increased or decreased by the advancement / retraction of the advance / retreat portion and the resistance flow path for allowing the liquid to flow into and out of the storage portion is provided, the resistance flow is caused by the advance / retreat of the advance / retreat portion. A damping force corresponding to the advance / retreat speed of the advance / retreat portion can be generated by the flow resistance of the liquid flowing through the path. In addition, since the damping part is provided in the housing part, it is easy to consolidate the structure capable of suppressing the jumping of the core components into the housing part.

According to a third aspect of the present invention, in the second aspect, the core component may include a biasing portion that biases the advance / retreat portion downward.
According to this configuration, the advancing / retreating portion is urged downward by the urging portion, so that the advancing / retreating portion can reliably project from the shape changing portion when the core component is displaced upward from the support structure. Therefore, it is easy to reliably suppress the core component from jumping up from the support structure when vertical vibration is applied to the core component.

  According to a fourth aspect of the present invention, in the third aspect, the core component has a cylindrical shape filled with the liquid, and the urging portion includes the accommodating portion as the core configuration. There may be provided a communication opening portion opened in the element, and a pressure receiving portion that is provided in the advance / retreat portion and is pressed downward by the pressure in the core component through the communication opening portion. .

The liquid flows into the reservoir from the inside of the core component through the communication opening. For this reason, the pressure of the liquid in a storage part is low compared with the inside of a core component by the pressure loss in a communicating opening part.
And according to the said structure, the urging | biasing part has a communicating opening part which made the accommodating part open in a core component, and the pressure receiving part of an advancing / retreating part. Therefore, when the core component is displaced upward, a high pressure in the core component acts on the pressure receiving portion of the advance / retreat portion, and a low pressure around the core component above the support structure acts on the lower end side of the advance / retreat portion. Therefore, the advance / retreat portion can be urged downward by the differential pressure between the inside of the core component and the inside of the storage portion.
As a result, when the core component is displaced upward, the advancing / retreating portion can be reliably projected downward, and it is not necessary to install a mechanical member or the like for biasing, and simplification can be achieved.

  According to a fifth aspect of the present invention, in the third aspect, the storage portion has a bottomed shape that opens downward, and the storage portion is between the bottom portion of the storage portion and the advance / retreat portion. The resistance flow path may be provided between the inner peripheral side surface of the accommodating portion and the outer peripheral side surface of the advance / retreat portion, and the biasing portion may be an elastic member disposed in the accommodating portion.

  According to this configuration, the advancing / retreating portion and the elastic member are disposed in the bottomed hole-shaped accommodation portion, and the storage portion and the resistance flow path are provided. Therefore, the structure for suppressing the jumping of the core component can be concentrated in the housing portion, and the advancement / retraction portion can be reliably protruded from the shape changing portion by the elastic member, thereby suppressing the jumping of the core component.

  According to a sixth aspect of the present invention, in the fifth aspect, the connecting pipe is provided with a protruding portion that can contact the core component from below at a position different from the accommodating portion. It may be done.

  According to such a configuration, in a state where the core component is seated on the support structure, the protruding portion can support the core component from below at a position where the accommodating portion is not provided around the advance / retreat portion. For this reason, it can avoid that all the loads are applied to the advance / retreat portion from the support structure. Therefore, it can avoid that an elastic member vibrates and a seating state becomes unstable. In addition, in a state where the core component is seated on the support structure, for example, excessive compression of the elastic member can be prevented.

  According to a seventh aspect of the present invention, in the fifth or sixth aspect, a concave storage portion that can accommodate the elastic member may be provided on an upper end surface of the advance / retreat portion.

  According to such a structure, since the storage part is provided in the upper end surface of the advancing / retreating part, the urging | biasing part which is an elastic member can be accommodated in a storage part in the state in which the core component was seated on the support structure. Therefore, it is possible to avoid excessive compression of the elastic member in a state where the core component is seated on the support structure.

  ADVANTAGE OF THE INVENTION According to this invention, the nuclear reactor which can provide easily the structure which can suppress the jump of the core component by the vibration of an up-down direction can be provided.

It is a figure showing composition of a nuclear reactor concerning a first embodiment of the present invention. It is a perspective view showing a core component concerning a first embodiment of the present invention. It is an expanded sectional view showing composition of a core constituent concerning a first embodiment of the present invention, and a support structure, and shows a state where a core constituent was seated on a support structure. It is an expanded sectional view showing composition of a core constituent concerning a first embodiment of the present invention, and a support structure, and shows a state where a core constituent was displaced upwards from a support structure. It is an expanded sectional view showing the composition of the core component concerning a first embodiment of the present invention, and a support structure, and after the core component is displaced upward from the support structure, the core component goes on the lower support structure The displaced state is shown. It is an expanded sectional view showing the energizing part and attenuation part of the core component concerning a first embodiment of the present invention. It is an expanded sectional view showing the composition of the core component concerning a second embodiment of the present invention, and a support structure, and shows the state where the core component was seated on the support structure. It is an expanded sectional view which shows the structure of the core structural element which concerns on 2nd embodiment of this invention, and a support structure, and shows the state which the core structural element displaced upwards from the support structure. It is an expanded sectional view showing the composition of the core component concerning a second embodiment of the present invention, and a support structure, and after the core component displaced upward from the support structure, the core component displaced on the lower support structure Indicates the state. It is an expanded sectional view which shows the urging | biasing part and attenuation | damping part of the core component which concerns on 2nd embodiment of this invention. It is an expanded sectional view which shows the urging | biasing part and attenuation | damping part of the core component which concerns on 3rd embodiment of this invention. It is an expanded sectional view which shows the urging | biasing part and attenuation | damping part of the core component which concerns on 4th embodiment of this invention.

[First embodiment]
A first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, a nuclear reactor 1 according to this embodiment includes a nuclear reactor vessel 2, a core 3, a support structure 4, and an upper structure 5.

  The reactor vessel 2 includes a reactor vessel body 6, a shielding plug 7, a coolant inlet pipe 8 and a coolant outlet pipe 9, and a partition wall 10. An opening 11 is formed in the upper part of the reactor vessel body 6 and is stored in a reactor containment vessel (not shown) with the bottom opposite to the upper part facing vertically downward. The shielding plug 7 is disposed in the opening 11 in the reactor vessel body 6 to seal the opening 11. The coolant inlet pipe 8 and the coolant outlet pipe 9 form an inlet / outlet of the coolant C (primary main coolant) into the reactor vessel 2. The partition wall 10 is a plate-like member having an opening at the center. The partition wall 10 extends in the horizontal direction inside the reactor vessel 2, thereby dividing the inside of the reactor vessel 2 in the vertical direction. Further, the inside of the reactor vessel 2 is filled with a coolant C as a liquid.

  The reactor core 3 mainly has a fuel rod assembly and a control rod assembly, and is disposed in the central portion in the reactor vessel 2. Here, elements constituting the core 3 such as a fuel rod assembly and a control rod assembly are collectively referred to as a core component 14. Note that the support structure 4 according to the present embodiment can be particularly preferably employed for the fuel rod 15 in the core component 14.

As shown in FIGS. 1 and 2, the support structure 4 is a structure provided in the reactor vessel 2 to support the core component 14 from below. Located in the center. The partition wall 10 is fixed to the support structure 4 and the reactor vessel 2.
The support structure 4 includes a support plate 12 extending in the horizontal direction, and a plurality of connecting pipes 13 inserted into and supported by the support plate 12 from above. The connecting pipe 13 has a cylindrical shape extending in the vertical direction and is arranged in the horizontal direction. One core component 14 is disposed in each connecting pipe 13 (see FIG. 2).

  The superstructure 5 includes, for example, a driving device for driving a control rod that is the core component 14. The upper structure 5 is disposed above the core 3, penetrates the shielding plug 7 in the vertical direction, and is fixed to the reactor vessel 2 by the shielding plug 7.

Next, the configuration of the support structure 4 and the core component 14 will be described in detail.
The support structure 4 includes a support plate 12 that extends in the horizontal direction, and a plurality of connecting pipes 13 that are supported by the support plate 12. The support plate 12 has an upper plate portion 24 and a lower plate portion 25 that are arranged with an interval in the direction of the axis Ac (vertical direction) (see FIG. 1). Part of the coolant C flows in the space between the upper plate portion 24 and the lower plate portion 25.

The connecting pipe 13 is supported by being inserted into the insertion holes 26 of the upper plate portion 24 and the lower plate portion 25 from above. The connecting pipe 13 according to the present embodiment includes a cylindrical part 28 and a connecting pipe side step part 30.
The cylindrical portion 28 is a portion that is inserted into the support structure 4, and between the inner peripheral surface of the cylindrical portion 28 and the outer peripheral surface of the entrance nozzle 16 in a state where the fuel rod 15 is inserted into the connecting pipe 13. Is formed with a gap 31. The gap 31 has a ring shape when viewed from the direction of the axis Ac and is a space that extends over the direction of the axis Ac, and the inflow hole 20 of the entrance nozzle 16 is disposed therein.

  An opening 32 that faces the space between the upper plate portion 24 and the lower plate portion 25 is formed in the central portion of the cylindrical portion 28 in the axis Ac direction. A part of the coolant C flowing through the space between the upper plate portion 24 and the lower plate portion 25 is taken into the gap 31 through the opening 32.

The connecting pipe side step portion 30 includes an annular flange portion 36 that comes into contact with the upper surface of the upper plate portion 24, and a step portion main body 37 that is integrally provided on the inner peripheral side of the flange portion 36. ing.
The flange portion 36 is larger than the opening size of the insertion opening 26. When the flange portion 36 comes into contact with the upper plate portion 24 from above, the connecting pipe 13 is supported without dropping downward.

The stepped portion main body 37 is a portion that supports the nozzle-side stepped portion 18 of the fuel rod 15 from the upper side and supports the outer surface 23 of the nozzle-side stepped portion 18 of the fuel rod 15 from the outer peripheral side and from below. Opposite facing surfaces 38 are provided. In the present embodiment, the facing surface 38 has a shape of a substantially frustoconical outer peripheral surface whose diameter increases toward the upper side corresponding to the outer surface 23 of the nozzle side step portion 18. Here, the facing surface 38 is not limited to the shape of the outer peripheral surface of the substantially truncated cone,
It may be curved.

The fuel rod 15 as the core component 14 has a columnar shape or a prismatic shape with an axis Ac extending in the vertical direction as the center. Specifically, the fuel rod 15 has an entrance nozzle 16 (small diameter portion) having a relatively small horizontal shape, and a cross-sectional shape that is positioned above the entrance nozzle 16 and has a relatively large horizontal shape. The fuel rod main body 17 (large diameter part) which has, and the nozzle side step part 18 (shape change part) which connects the entrance nozzle 16 and the fuel rod main body 17 to an up-down direction are provided.
The region inside the fuel rod 15 is formed hollow in the vertical direction. The hollow portion constitutes a part of the coolant channel 19 through which the coolant C flowing from the outside flows from below to above.

The entrance nozzle 16 is provided on the lower end side of the fuel rod 15 and is a part that is inserted into the support structure 4 by being inserted into the connecting pipe 13. The entrance nozzle 16 is formed with a plurality of inflow apertures 20 for taking the coolant C as a liquid flowing through the periphery into the coolant channel 19. The lower end of the entrance nozzle 16 is sealed with a sealing member 21.
The fuel rod main body 17 is a member forming a main part of the fuel rod 15 by incorporating nuclear fuel or the like. The fuel rod body 17 has a hexagonal cross-sectional shape when viewed from the direction of the axis Ac. The space inside the fuel rod main body 17 constitutes a part of the coolant channel 19.

  The nozzle-side step portion 18 is located between the entrance nozzle 16 and the fuel rod main body 17 and is a part that coaxially connects the entrance nozzle 16 and the fuel rod main body 17 along the axis Ac. More specifically, the nozzle side step portion 18 has an outer surface 23 that gradually increases in diameter from the entrance nozzle 16 side toward the fuel rod body 17 side. The outer surface 23 may be conical, spherical, curved or the like.

The nozzle side step portion 18 of the fuel rod 15 includes an accommodating portion 40, an advancing / retracting portion 41 accommodated in the accommodating portion 40, an urging portion 42 provided to urge the advancing / retreating portion 41, And a damping part 43 provided so as to generate a damping force when moving forward and backward.
The accommodating portion 40 is a hollow portion provided in the fuel rod 15 along the axis Ac that extends in the up-down direction, and is provided to open on the outer surface of the nozzle side step portion 18 facing the connecting pipe 13. Although the accommodating part 40 is good also as a single hole or a some hole, in this embodiment, it is comprised by the gap | interval provided in arc shape or cyclic | annular form. In this accommodating part 40, it is good that the horizontal cross-sectional shape continues in a substantially constant shape along the axis line Ac.

The accommodating portion 40 according to the present embodiment includes a space around the outer surface 23 of the nozzle side step portion 18, that is, a space around the outside of the fuel rod 15 above the support structure 4, and a coolant channel 19 inside the fuel rod 15. Between the top and bottom.
The accommodating portion 40 has a lower accommodating portion 44 on the lower end side and an upper accommodating portion 45 on the upper end side. The upper accommodating portion 45 is formed thicker than the lower accommodating portion 44, and a communication opening 46 that opens to the coolant channel 19 is provided at the upper end.

The advancing / retreating portion 41 has a shape along the axis Ac extending in the vertical direction, and is accommodated in the accommodating portion 40 so as to be able to project and retract downward. The advance / retreat portion 41 has a lower advance / retreat portion 47 on the lower end side and an upper advance / retreat portion 48 on the upper end side.
The lower advancing / retracting portion 47 has a horizontal cross-sectional shape corresponding to the lower accommodating portion 44 of the accommodating portion 40. The lower advancing / retracting portion 47 is formed to be narrower than the lower accommodating portion 44, thereby forming a resistance flow path 49 including a gap extending in the vertical direction between the lower advancing / retreating portion 47 and the lower accommodating portion 44.
In a state where the advancing / retreating portion 41 is sunk upward, that is, in a state where it is disposed at the top, the upper end side of the lower advancing / retreating portion 47 is disposed in the upper accommodating portion 45, and is stored between the lower advancing / retreating portion 47 and the upper accommodating portion 45. Part 50 is formed.

  A spherical seat 51 having a spherical shape protruding downward is provided on the lower end surface of the lower advancement / retraction portion 47. The spherical seat 51 is in contact with the facing surface 38 of the connecting pipe 13. The lower end surface of the lower advance / retreat portion 47 is disposed at a position substantially continuous with the outer surface 23 of the nozzle side step portion 18 with the advance / retreat portion 41 being disposed at the uppermost portion.

The upper advance / retreat portion 48 of the advance / retreat portion 41 has a horizontal sectional shape corresponding to the upper accommodation portion 45 of the accommodation portion 40 and is formed in a plate shape. By accommodating the upper advance / retreat part 48 in the upper accommodation part 45, the upper end of the storage part 50 formed below the upper advance / retreat part 48 is closed.
A minute gap is provided between the upper advancing / retracting portion 48 and the upper accommodating portion 45.

  The urging portion 42 has a structure for urging the advance / retreat portion 41 accommodated in the accommodating portion 40 downward. That is, the urging portion 42 according to the present embodiment is configured by using the communication opening portion 46 and the pressure receiving portion 52 provided in the upper advance / retreat portion 48 of the advance / retreat portion 41. Pressure is applied to the pressure receiving portion 52 provided on the upper surface of the upper advance / retreat portion 48 from the coolant channel 19 in the fuel rod body 17 by a mechanism described later. The communication opening 46 is a minute gap provided between the upper advance / retreat part 48 and the upper housing part 45.

  The attenuating unit 43 has a structure that generates a damping force for the kinetic energy received by the advancing / retreating unit 41 according to the advancing / retreating speed of the advancing / retreating unit 41. That is, the attenuation unit 43 according to the present embodiment is configured using the resistance flow path 49 and the storage unit 50 formed between the storage unit 40 and the advance / retreat unit 41.

  Since the resistance flow path 49 is provided in the gap between the accommodating part 40 and the advance / retreat part 41, one end opens into the space around the outside of the fuel rod 15 above the support structure 4, and the other end is the storage part 50. Is open. The resistance flow path 49 has a length in the vertical direction of the lower housing portion 44 regardless of the advance / retreat position of the housing portion 40.

Since the upper end of the storage part 50 is closed by the upper advance / retreat part 48, the volume of the storage part 50 increases or decreases as the advance / retreat part 41 advances / retreats. In this configuration, the liquid flows into or out of the storage section 50 via the resistance channel 49 and the communication opening 46 by increasing or decreasing the volume of the storage section 50.
The attenuation unit 43 is configured to attenuate the kinetic energy received by the advancing / retreating unit 41 due to the flow resistance when the liquid flows into or out of the storage unit 50 via the resistance channel 49. The kinetic energy is also attenuated at the communication opening 46.

  In the nuclear reactor 1 as described above, heat is generated by the fission reaction in the core 3 (fuel rod 15) in a state where the core components are seated on the support structure during normal operation shown in FIG. Further, after the coolant C is supplied from the coolant inlet pipe 8 to the lower part in the reactor vessel 2, the coolant C flows upward from below. The coolant C absorbs the heat of the core 3 while passing through the inside of the fuel rod 15 through the connecting pipe 13. The coolant C that has reached a high temperature is delivered from the coolant outlet pipe 9 to the outside of the reactor vessel 2.

  Then, the coolant C of the coolant channel 19 flows into the storage unit 50 through the gap between the upper storage unit 45 of the storage unit 40 and the upper advance / retreat unit 48 of the advance / retreat unit 41, and the resistance channel from the storage unit 50. 49 flows out around the fuel rod 15. Since the coolant C flows into the reservoir 50 from a narrow gap (communication opening 46) between the upper accommodating portion 45 and the upper advance / retreat portion 48, the liquid in the reservoir 50 flows into the reservoir 50 due to pressure loss at that time. It is kept at a lower pressure than the road 19.

  Therefore, due to the pressure difference between the coolant C in the reservoir 50 and the coolant C in the coolant channel 19, the urging portion 42 is constantly loaded with a downward force on the pressure receiving portion 52, so that it advances and retreats. The part 41 is urged downward.

  When the advancing / retreating portion 41 is biased downward, the spherical seat 51 provided in the lower advancing / retreating portion 47 makes line contact with the substantially conical facing surface 38 of the connecting pipe 13 in a pressurized state. Since the pressure in the coolant channel 19 is applied to the pressure receiving portion 52 and the advance / retreat portion 41 is urged downward, the fuel rod 15 is supported by the support structure 4 by the urging force.

  When a vertical vibration is applied to the reactor 1 due to an earthquake or the like and the fuel rod 15 is displaced upward from the support structure 4 as shown in FIG. 4, for example, jumps up, the coolant channel 19 and the reservoir 50 Due to the pressure difference, the advance / retreat portion 41 protrudes downward from the nozzle side step portion 18.

  After that, as shown in FIGS. 5 and 6, when the fuel rod 15 displaced upward is displaced toward the lower support structure 4, for example, falls onto the support structure 4, the attenuation portion 43 moves downward from the nozzle side step portion 18. The advancing / retreating portion 41 that protrudes toward the first contacts the connecting pipe 13 of the support structure 4 from above and is accommodated in the accommodating portion 40.

  At this time, the fuel rod 15 is displaced onto the support structure 4 and the advance / retreat portion 41 sinks and retracts, whereby the volume of the storage portion 50 increases, flows through the resistance flow path 49, and flows into the storage portion 50 as a coolant. Aspirate C. Further, in the resistance flow path 49, the liquid flows corresponding to the advance / retreat speed of the advance / retreat section 41 and a flow resistance is generated. At this time, since the flow velocity of the coolant C flowing through the resistance flow path 49 and the communication opening 46 increases rapidly, the advance / retreat portion 41 functions as a dashpot, and the advance / retreat portion 41 responds to the kinetic energy received from the support structure 4. A damping force is generated, and the impact when the fuel rod 15 displaced upward is displaced onto the support structure 4 can be mitigated.

  According to the nuclear reactor 1 as described above, the advancing / retreating part 41 accommodated in the accommodating part 40 so as to be able to project and retract is configured to sunk while generating a damping force by contacting the connecting pipe 13 from above. As a result, it is possible to prevent the fuel rod 15 from jumping up from the support structure 4 even when a vertical vibration is applied.

  That is, in the nuclear reactor 1 of the present embodiment, the advancing / retreating portion 41 is urged downward by the urging portion 42 due to the pressure difference of the coolant C. Therefore, when the fuel rod 15 is displaced upward from the support structure 4, The advancing / retreating portion 41 can be reliably projected from the nozzle side step portion 18. The advancing / retreating portion 41 again comes into contact with the support structure 4 and retreats, so that the advancing / retreating portion 41 functions as a so-called dashpot. It is possible to generate a damping force according to the moving speed.

  Therefore, it is not necessary to separately install a mechanical member for urging the advance / retreat portion 41 downward, and the damping portion 43 is provided in the accommodation portion 40, so that a structure that suppresses the jumping of the fuel rod 15 is easily integrated in the accommodation portion 40. . While simplifying the structure, it is possible to reliably suppress the fuel rod 15 from jumping up from the support structure 4 when vertical vibration is applied to the nuclear reactor 1.

Since the housing portion 40 and the advancing / retreating portion 41 are provided in the fuel rod 15, it is necessary to provide the connecting pipe 13 of the support structure 4 with a structure for preventing the fuel rod 15 from jumping up. Therefore, the degree of freedom of the structure of the connecting pipe 13 can be ensured. For example, it is possible to realize a structure for suppressing the jumping of the fuel rod 15 by using the existing nuclear reactor support structure 4 and the connecting pipe 13 as they are.
Therefore, in the nuclear reactor 1 of this embodiment, it is possible to easily provide a structure that can suppress the jumping of the fuel rod 15 due to vertical vibration.

  In the above embodiment, the case where the fuel rod 15 as the core component 14 is supported by the support structure 4 has been described. However, as the core component 14, in addition to the fuel rod 15, it is also possible to use a control rod guide tube for guiding the vertical movement of the control rod. Even if it is such a structure, the effect similar to the said embodiment can be acquired.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS. In addition, about the structure similar to said 1st embodiment, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.
The nuclear reactor 1A of the second embodiment is the same as that of the first embodiment except that the configuration of the core component 14 is different.

  In the fuel rod 15 which is the core component 14 of the nuclear reactor 1A according to the second embodiment, the nozzle side step portion 18 of the fuel rod 15 includes the accommodating portion 40A, the advance / retreat portion 41A accommodated in the accommodating portion 40A, and the advance / retreat portion. An urging portion 42A provided to urge the portion 41 and an attenuating portion 43A provided to generate a damping force by the advance / retreat of the advance / retreat portion 41 are provided.

In the second embodiment, the accommodating portion 40A is provided in a bottomed groove shape that opens downward. The horizontal cross-sectional shape of the accommodating portion 40A is substantially constant along the axis Ac that extends in the vertical direction.
The advance / retreat part 41A has a shape along the axis Ac extending in the vertical direction, and is accommodated in the accommodation part 40A so as to protrude and retract downward.

  A storage portion 50A is provided between the upper end of the advance / retreat portion 41A and the bottom portion of the upper end of the storage portion 40A in a state where the advance / retreat portion 41A is sunk upward. The urging portion 42A is configured by an elastic member 53 such as a spring disposed in the storage portion 50A in the accommodating portion 40A.

  From a gap extending vertically between one or both of the inner inner peripheral side surface of the accommodating portion 40A and the inner outer peripheral side surface of the advance / retreat portion 41A, or between the outer inner peripheral side surface of the accommodating portion 40A and the outer outer peripheral side surface of the advance / retreat portion 41A. A resistance flow path 49A is provided. The resistance flow path 49A communicates vertically between the space around the outer surface 23 of the nozzle side step portion 18 and the storage portion 50A.

In the nuclear reactor 1A according to the second embodiment, the advance / retreat portion 41A is urged downward by the elastic member 53 during normal operation in a state where the core components shown in FIG. 7 are seated on the support structure. In addition, the reservoir 50A is filled with the liquid made of the coolant C.
When a vertical vibration is applied to the reactor 1 due to an earthquake or the like and the fuel rod 15 is displaced upward from the support structure 4 as shown in FIG. Projects downward from the portion 18.
Along with this, the volume of the reservoir 50A increases, and the coolant C flows from the space around the nozzle-side stepped portion 18 or the coolant channel 19, for example.

  9 and 10, when the fuel rod 15 displaced upward is displaced toward the lower support structure 4, the advancing / retreating portion 41A protruding downward from the nozzle-side step portion 18 is first provided in the damping portion 43A. It contacts the connecting pipe 13 of the support structure 4 from above and sinks into the accommodating portion 40A and is accommodated in the accommodating portion 40A.

As the fuel rod 15 is displaced onto the support structure 4 and the advance / retreat portion 41 sinks and retracts, the volume of the reservoir 50A decreases, flows through the resistance channel 49A, and flows out the coolant C from the reservoir 50A. To do. In the resistance flow path 49A, the flow rate of the coolant C increases rapidly, and the liquid flows corresponding to the advance / retreat speed of the advance / retreat part 41A to generate a flow resistance. Therefore, the advance / retreat part 41A according to the advance / retreat speed of the advance / retreat part 41A. The movement resistance is generated.
As a result, a damping force with respect to the kinetic energy received by the advance / retreat portion 41A is generated, and the impact when the fuel rod 15 displaced upward is displaced onto the support structure 4 can be attenuated. As a result, even if vertical vibration is applied due to an earthquake or the like, the jumping of the fuel rod 15 can be suppressed.

Also in the nuclear reactor 1A of the second embodiment, the same effect as the first embodiment can be obtained.
That is, the advancing / retreating portion 41A accommodated in the accommodating portion 40A so as to be able to project and retract is configured to sink while generating a damping force by coming into contact with the connecting tube 13 from above, and is connected to the connecting tube 13 of the support structure 4 or the like. There is no need to separately provide a structure for suppressing the jumping of the fuel rod 15. Therefore, it is possible to prevent the fuel rod 15 from jumping up from the support structure 4 while ensuring the degree of freedom of the structure of the connecting pipe 13.

Further, since the damping portion 43A having the storage portion 50A whose volume increases and decreases by the advancement and retraction of the advance / retreat portion 41A and the resistance flow path 49A for flowing the coolant C into and out of the storage portion 50A is provided, the flow of the coolant C A damping force corresponding to the advance / retreat speed of the advance / retreat portion 41A can be generated by the resistance.
Further, since the advancing / retreating portion 41A is urged downward by the urging portion 42A that is the elastic member 53, the advancing / retreating portion 41A is reliably projected from the nozzle side step portion 18 when displaced upward from the support structure 4. Can do.

  Moreover, in the nuclear reactor 1A of the second embodiment, the elastic member 53 of the advance / retreat portion 41A and the urging portion 42A is disposed in the bottomed hole-shaped storage portion 40A, and the storage portion 50A and the resistance flow path 49A are provided. Even so, the structure for suppressing the jumping of the fuel rod 15 can be concentrated in the accommodating portion 40A.

  Here, in the present embodiment, a communication path (for example, the communication opening 46 of the first embodiment) that communicates the upper surface of the accommodating portion 40A and the coolant channel 19 may be provided. Thereby, 41 A of advance / retreat parts can be urged | biased by the pressure difference of the coolant C similarly to 1st embodiment.

[Third embodiment]
Next, a third embodiment of the present invention will be described with reference to FIG. In addition, about the structure similar to said 2nd embodiment, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.
The nuclear reactor 1B of the third embodiment is the same as that of the second embodiment except that the configuration of the upper end surface of the connecting pipe 13 is different.
As shown in FIG. 11, in the nuclear reactor 1 </ b> B of the third embodiment, a spherical seat 54 (protruding portion) that protrudes upward is provided on the connecting tube side step portion 30 of the connecting tube 13.
The spherical seat 54 is provided in an annular shape with the axis Ac as the center, and is disposed to face a position different from the accommodating portion 40A and the advance / retreat portion 41A in the nozzle side step portion 18.

In such a nuclear reactor 1B of the third embodiment, the same effects as those of the second embodiment can be obtained.
Further, in the present embodiment, in a state where the core component 14 is seated on the support structure 4, the spherical seat 54 abuts on the nozzle side step portion 18, thereby restricting the vertical position of the fuel rod 15 and the connecting pipe 13. can do.

Therefore, in a state where the core component 14 is seated on the support structure 4, it can be avoided that the elastic member 53 vibrates and the seating state becomes unstable.
Further, in a state where the core component 14 is seated on the support structure 4, for example, the elastic member 53 can be prevented from being excessively compressed, and the load from the support structure 4 on the advance / retreat portion 41A can also be avoided. .
Here, the spherical seat 54 is not limited to the case where it is provided on the connecting pipe 13 side, and may be provided on the nozzle side step portion 18 side. That is, the spherical seat 54 may be provided on the core component 14 so as to be opposed to the connecting pipe 13 (the connecting pipe side stepped portion 30) at a position different from the accommodating part 40 and to contact the connecting pipe 13 from above. Good. Even in this case, the seating state of the support structure 4 can be prevented from becoming unstable, and the elastic member 53 can be prevented from being excessively compressed.

[Fourth embodiment]
Next, a fourth embodiment of the present invention will be described with reference to FIG. In addition, about the structure similar to said 2nd embodiment and 3rd embodiment, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.
The nuclear reactor 1C of the fourth embodiment is the same as the second embodiment except that the configuration of the advance / retreat section 41 is different.
As shown in FIG. 12, in the nuclear reactor 1 </ b> C of the fourth embodiment, a concave storage portion 55 that houses the elastic member 53 by being recessed downward from the upper end surface of the advance / retreat portion 41 </ b> C is provided. Thus, a protruding edge portion 56 is provided on the upper end surface of the advance / retreat portion 41C so as to protrude upward at the positions of the radially outer and inner end portions. When the section along the axis Ac is viewed, the radially outer and inner protruding edges 56 gradually decrease in thickness toward the upper side. That is, the storage portion 55 has a trapezoidal shape in which the radial dimension gradually increases upward when viewing the cross section along the axis Ac. However, the storage portion 55 is not limited to such a shape, and may simply have a shape that can accommodate the elastic member 53.

In such a nuclear reactor 1 </ b> C of the fourth embodiment, the same effects as those of the second embodiment can be obtained.
In particular, in the present embodiment, since the storage portion 55 is provided on the upper end surface of the advance / retreat portion 41C, the upper end of the protruding edge portion 56 is a bottomed storage portion in a state where the core component 14 is seated on the support structure 4. The abutting portion 42 </ b> A that is the elastic member 53 can be accommodated in the storage portion 55 by contacting the upper end portion of 40 </ b> A.
Therefore, it is possible to prevent the elastic member 53 from being excessively compressed in a state where the core component is seated on the support structure.

The embodiments of the present invention have been described above with reference to the drawings. Note that each of the above embodiments is merely an example, and various modifications can be made to the above configuration without departing from the gist of the present invention.
For example, in each embodiment, although the example which provided the urging | biasing part 42 (42A) and the attenuation | damping part 43 (43A) in the clearance gap between the accommodating part 40 and the advance / retreat part 41 (41A, 41C) was demonstrated, it is specifically limited. Instead of this, it is also possible to apply an urging force or a damping force to the advancing / retreating part 41 accommodated in the accommodating part 40.

DESCRIPTION OF SYMBOLS 1, 1A, 1B, 1C ... Reactor 2 ... Reactor vessel 3 ... Core 4 ... Support structure 5 ... Upper structure 6 ... Reactor vessel body 7 ... Shield plug 8 ... Coolant inlet piping 9 ... Coolant outlet piping 10 ... partition wall 11 ... opening part 12 ... support plate 13 ... connecting pipe 14 ... core component 15 ... fuel rod 16 ... entrance nozzle 17 ... fuel rod body 18 ... nozzle side step part 19 ... coolant channel 20 ... inflow opening DESCRIPTION OF SYMBOLS 21 ... Sealing member 23 ... Outer surface 24 ... Upper side plate part 25 ... Lower side plate part 26 ... Insertion hole 28 ... Cylindrical part 30 ... Connecting pipe side step part 31 ... Gap 32 ... Opening 36 ... Flange part 37 ... Step Part main body 38 ... opposing surfaces 40, 40A ... accommodating parts 41, 41A, 41C ... advance / retreat parts 42, 42A ... biasing parts 43, 43A ... damping part 44 ... lower accommodating part 45 ... upper accommodating part 46 ... communication opening 47 ... Lower advancing / retracting portion 48... Upper advancing / retreating portion 49, 49 A. , 50A ... storage portion 51 ... spherical seat 52 ... pressure receiving portion 53 ... resilient member 54 ... spherical seat 55 ... storage unit 56 ... protruding edge Ac ... axis C ... coolant

Claims (7)

A reactor vessel filled with a liquid,
A connecting pipe provided in the reactor vessel, having a cylindrical shape extending in the vertical direction and arranged in a plurality in the horizontal direction, and a support structure having a support plate extending in the horizontal direction to support the connecting pipe;
A small-diameter portion inserted into the connecting pipe, a large-diameter portion positioned above the small-diameter portion, and positioned between the small-diameter portion and the large-diameter portion so as to contact and support the connecting tube from above. A core component having a shape change portion,
With
The core component is provided in the shape changing portion and is opened facing the connecting tube, and is accommodated in the receiving portion so as to be able to project and retract downward, and comes into contact with the connecting tube from above. And an advancing / retreating part that sinks while generating a damping force.   The said core component WHEREIN: The attenuation | damping part which has the storage part to which a volume is increased / decreased by the advance / retreat of the said advancing / retreating part, and the resistance flow path into which the said liquid flows in / out is provided in the said accommodating part. The nuclear reactor described in 1.   The nuclear reactor according to claim 2, wherein the core component includes a biasing portion that biases the advance / retreat portion downward. The core component has a cylindrical shape filled with the liquid,
The urging portion is provided with a communication opening portion in which the housing portion is opened in the core component, and is provided in the advancement / retraction portion, and is pressed downward by the pressure in the core component through the communication opening portion. The nuclear reactor according to claim 3, further comprising: a pressure receiving portion. The housing portion has a bottomed shape opened downward,
The storage portion is provided between the bottom portion of the housing portion and the advance / retreat portion,
The resistance flow path between the inner peripheral side surface of the accommodating portion and the outer peripheral side surface of the advance / retreat portion is provided,
The nuclear reactor according to claim 3, wherein the urging portion is an elastic member disposed in the accommodating portion.   The nuclear reactor according to claim 5, wherein the connecting pipe is provided with a protruding portion that can face the core component at a position different from the accommodating portion and can contact from below.   The nuclear reactor according to claim 5 or 6, wherein a concave storage part capable of accommodating the elastic member is provided on an upper end surface of the advance / retreat part.

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