JP2015158471A - Fuel exchange system and nuclear reactor system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve compactification of a nuclear reactor vessel of a fast reactor performing fuel exchange.SOLUTION: A nuclear reactor system 100 includes: a furnace core 2; a nuclear reactor vessel 10; a furnace core supporting plate; a shielding plug; a furnace core barrel 4; a plurality of reflectors; a partition wall 7; a plurality of intermediate heat exchangers 16; a plurality of built-in pumps 17; a reactor shutdown rod drive mechanism; and a fuel exchange system. The fuel exchange system includes: a reactor in-vessel relay section 21 provided inside the nuclear reactor vessel 10; a fuel handling machine transferring a transfer object fuel assembly between the furnace core 2 and the reactor in-vessel relay section 21; and a fuel entrance and exit portion allowing the transfer object fuel assembly to be transferred between the reactor in-vessel relay section 21 and an outside of the nuclear reactor vessel 10. A partition wall protrusion portion 22 protruding to an outside in a radial direction is formed on the partition wall 7, and the reactor in-vessel relay section 21 is provided inside the partition wall protrusion portion 22.

Description

  Embodiments described herein relate generally to a fast reactor fuel exchange system and a nuclear reactor system using the same.

  In light water-cooled reactors, when replacing the fuel, the reactor pressure vessel top lid is removed when the reactor is shut down, the core is opened, and the fuel loaded in the core is lifted directly from the loaded location. Can be taken out. On the contrary, the new fuel can be loaded directly from above into the loading place.

  On the other hand, in a liquid metal cooled fast reactor, it is necessary to avoid oxidation due to contact of liquid metal, for example, sodium, which is a reactor coolant with outside air, or mixing of outside air into the cover gas. Therefore, it is necessary to perform fuel exchange by isolating the inside of the reactor vessel from the outside air and sealing the inside of the reactor vessel. That is, since it is necessary to carry out in the state where there is a shielding plug that is a lid of the reactor vessel, the fuel loaded in each position of the reactor core cannot be pulled out and taken out as it is. Moreover, it is necessary to penetrate the shielding plug in the route to be taken out. From the point of penetrating the shielding plug, the penetration location is limited. Also, the penetration portion needs to be limited to a specific location in view of the relationship with the fuel transfer path above the shielding plug.

  Under such conditions, the fuel exchange in the liquid metal cooled fast reactor is basically performed firstly between the core and the position corresponding to the specific location in the reactor vessel, Secondly, a system having at least two transfer steps of transfer between a position corresponding to the specific location and the outside of the reactor vessel is common.

  In particular, with regard to the first transfer, a method for ensuring accessibility to each part of the core and a specific location by providing a rotating plug and combining the rotating plug and the fuel exchanger, and a method for ensuring the same accessibility only by the fuel exchanger. There is. In addition, there is a method that further includes a step between the first transfer and the second transfer.

  FIG. 10 is an elevational sectional view showing an example of a conventional configuration in the case of a fuel exchange system that ensures accessibility by using only a fuel exchanger without using a rotary plug (see Patent Document 1). That is, a variable arm type fuel handling device 210 having a lifting / lowering / rotating function is provided in the central portion of the upper lid of the reactor vessel 10 or in the vicinity thereof. The variable arm type fuel handling machine 210 has an arm 212 at the lower end of the fuel handling machine main body 211. A hold-down tube 213 is connected to the tip of the arm 212, and the first transfer is performed by the horizontal expansion and contraction of the arm 212 and the raising / lowering / rotating operation of the fuel handling machine body 211.

  The second transfer, that is, the transfer of the fuel assembly inside and outside the reactor vessel 10 is performed through a fuel transfer pot installed in the in-reactor relay tank 222 outside the reactor core 2. An in-furnace relay device 220 is provided above the in-furnace relay tank 222, and fuel is taken out via an access door valve 221 provided on the roof deck 201 by a fuel inlet / outlet machine that accesses the upper part of the shielding plug directly above. Is entered. Here, in the example shown in FIG. 10, the in-furnace relay tank 222 is provided in a region in the core tank 4.

  FIG. 11 is an elevational sectional view showing an example of the configuration of a conventional reactor system 100 for a small fast reactor. FIG. 12 is a horizontal sectional view showing an example of the configuration of a conventional reactor system 100 for a small fast reactor. The small fast reactor shown here is an example in which the diameter of the reactor vessel 10 is about 3 to 5 m (see Patent Document 2).

  This small fast reactor has a core 2 in a reactor vessel 10. The fuel assembly 1 constituting the core 2 is mounted on a core support 6b via a flow adjustment module 6c for flow rate distribution. The core 2 is formed in a substantially cylindrical shape. A core tank 4 that protects the core 2 is provided on the outer periphery of the core 2. A plurality of reflectors 5 that are partially arc-shaped and extend up and down are arranged outside the reactor core 4. The reflector 5 is connected to a reflector driving mechanism 5a installed on the upper surface of the shielding plug 11 via a reflector driving shaft 5b. The reactivity of the core 2 is controlled by the reflector 5 being driven by the reflector drive mechanism 5 a and moving up and down around the core 2. The plurality of reflectors 5 are arranged so as to surround the core 2 in an annular shape in the circumferential direction at intervals. A neutron detector 19 is disposed between the adjacent reflectors 5.

  A cylindrical partition wall 202 surrounding the reflector 5 is provided outside the reflector 5, and the coolant that has risen in the reactor core 2 is folded back above the reactor core 2 between the partition wall 202 and the reactor vessel 10. After that, a descending flow path for the primary coolant descending is formed. In this descending flow path, an annular intermediate heat exchanger 251 formed in an annular shape, an annular electromagnetic pump 252 for main circulation formed in an annular shape, and a neutron shield 8 are sequentially formed from top to bottom in the vertical direction. Each is provided so as to surround the partition wall. The core 2, the reactor core 4, the partition wall 202, and the neutron shield 8 are all mounted on the core support plate 6 and supported by the core support plate 6.

  The guard vessel 12 is provided so as to cover the side surface and the outside of the bottom surface of the reactor vessel 10. The top dome 13 is provided so as to cover the side surface and the upper portion of the shielding plug 11. The guard vessel 12 and the top dome 13 are connected to each other and constitute a sealed space as a storage barrier. The top dome 13 is surrounded by the reactor building 300.

  Inside the reactor vessel 10 outside the radial direction of the core 2, a cylindrical core tank 4 having an open top and bottom is provided so as to surround the core 2. A plurality of reflectors 5 are provided in an annular space inside the partition wall 7, which will be described later, outside the core tank 4 in the radial direction.

  A reflector upper shielding body 5 c is provided on the reflector 5. Further, the partition wall 7 forms an outer annular portion 15 between the inner wall of the reactor vessel 10. In addition, the part of the code | symbol 9 is a reactor stop rod drive mechanism, and the part of the code | symbol 18 shows the reactor pedestal which supports a shielding plug.

JP-A-11-190795 JP 2008-122248 A

  The small fast reactor shown in FIG. 11 and FIG. 12 shows an example of a nuclear reactor when no fuel replacement is required. On the other hand, for example, when this small fast reactor is applied to a nuclear reactor such as a material test reactor, fuel replacement is required. When the fuel exchange system shown in FIG. 10 is applied, in the small fast reactor having a plurality of reflectors 5 surrounding the core in an annular shape shown in FIGS. 11 and 12, the outer periphery of the region where the reflectors 5 are arranged is used. It is difficult to secure a space for installing the in-furnace relay tank 222 inside.

  Further, since the annular intermediate heat exchanger 251 or the annular electromagnetic pump 252 is arranged outside the area where the reflectors 5 are arranged, a space for installing the in-furnace relay tank 222 is also provided in this area. It cannot be secured.

  For this reason, it is necessary to provide a new space outside the region where the reflectors 5 are arranged and inside the annular intermediate heat exchanger 251 and the annular electromagnetic pump 252. As a result, the diameter of the reactor vessel 10 is increased by the provision of the in-reactor relay tank 222 (FIG. 10).

  Therefore, an object of the embodiment of the present invention is to reduce the size of a reactor vessel of a fast reactor that performs fuel replacement.

  In order to achieve the above object, an embodiment of the present invention provides a fast reactor core having a plurality of fuel assemblies that are arranged in parallel to each other and extend vertically, and the core, the reactor coolant, and the reactor coolant. A cylindrical reactor vessel that houses a cover gas that covers the top of the reactor and extends upward and downward, and is supported by the reactor vessel in the reactor vessel and extends horizontally to support the core A core support plate, a shielding plug that covers an upper part of the reactor vessel, a cylindrical core vessel that is provided in the reactor vessel around the radial direction of the core and that is open at the top and bottom to protect the core, and A plurality of reflectors movable up and down to control the reactivity by reflecting neutrons generated in the core provided to surround the reactor core as a whole inside the reactor vessel in the radial direction outside the reactor vessel; Before in the reactor vessel An ascending flow path provided outside the reflector in the radial direction, in which the reactor coolant ascends in the core, and an outer flow path after the reactor coolant is turned back radially outward above the core A partition wall having a substantially cylindrical shape that extends vertically and separates the outer annular portion and is open at the top and bottom, wherein a partition wall protruding portion that protrudes radially outward and extends to an upper end of the partition wall; and A plurality of intermediate heat exchangers provided at intervals in the circumferential direction of the outer annular portion, and the reactor provided at intervals in the circumferential direction of the outer annular portion and at intervals in the circumferential direction from the intermediate heat exchanger. A plurality of built-in pumps for circulating the reactor coolant in the vessel, a reactor stop rod for stopping the reaction in the reactor core, a reactor stop rod drive mechanism for driving the reactor stop rod, and the reactor core during fuel exchange Inside the fuel assembly Fuel exchange for transferring a transfer target fuel assembly from the core to the outside of the reactor vessel and transferring a new fuel assembly as the transfer target fuel assembly from the outside of the reactor vessel to the core A reactor system, wherein the fuel exchange system is provided in the bulkhead protrusion, and the relay part in the reactor vessel in which the transfer target fuel assembly can be temporarily placed, and during the fuel exchange A fuel handling machine for transferring the fuel assembly to be transferred between the reactor core and the relay part in the reactor vessel in the reactor vessel, and the relay part in the reactor container in the shielding plug at the time of the fuel change An opening for opening and closing a plug for opening and closing the transferable fuel assembly that can be opened and closed, formed in a portion directly above the reactor vessel, and the transfer between the relay portion in the reactor vessel and the outside of the reactor vessel And a fuel inlet / outlet part that allows the target fuel assembly to be transferred.

  Further, an embodiment of the present invention provides a fast reactor core including a plurality of fuel assemblies, a reactor vessel that houses the core, a shielding plug that covers an upper portion of the reactor vessel, and a periphery of the reactor core. A plurality of reflectors provided so as to surround the reactor core as a whole on the radially outer side of the reactor core, a partition provided on the radially outer side of the reflector, and a diameter of the partition A nuclear reactor system including a plurality of intermediate heat exchangers and a plurality of built-in pumps provided in an outer annular portion on the outer side in the direction, and a transfer target to be transferred among the fuel assemblies in the core at the time of fuel exchange A fuel exchange system for transferring a target fuel assembly from the core to the outside of the reactor vessel, and transferring a new fuel assembly as the transfer target fuel assembly from the outside of the reactor vessel to the core, The gap Is formed with a bulkhead projecting portion that projects radially outward and extends to the upper end of the bulkhead, and is provided inside the bulkhead projecting portion to relay the fuel assembly to be transferred temporarily in the reactor vessel. A fuel handling machine for transferring the transfer target fuel assembly, which is in the reactor vessel at the time of the fuel exchange and is to be transferred between the core and the relay portion in the reactor vessel, and at the time of the fuel change In the shielding plug, the shielding plug has an opening for opening and closing the shielding plug for opening and closing the transferable fuel assembly that is openable and closable and formed in a portion immediately above the relaying portion in the reactor vessel. And a fuel inlet / outlet part that allows the transfer target fuel assembly to be transferred to / from the outside of the reactor vessel.

  According to the embodiment of the present invention, the reactor vessel of the fast reactor that performs fuel replacement can be made compact.

It is an II sectional view taken on the line of FIG. 3 which shows the structure at the time of the fuel replacement | exchange of the nuclear reactor system which concerns on 1st Embodiment. FIG. 4 is a cross-sectional view taken along the line II-II in FIG. 3 showing a configuration of the nuclear reactor system according to the first embodiment when fuel is changed. FIG. 3 is a horizontal cross-sectional view taken along the line III-III in FIG. 1 showing the configuration of the nuclear reactor system according to the first embodiment during fuel replacement. FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3 showing a configuration during normal operation of the nuclear reactor system according to the first embodiment. It is an expanded sectional view which shows a part of fuel exchange system in the nuclear reactor system which concerns on 1st Embodiment. FIG. 6 is a horizontal sectional view taken along the line VI-VI in FIG. 1 illustrating the configuration of the nuclear reactor system according to the first embodiment. It is a flowchart which shows the procedure of the fuel exchange method in the nuclear reactor system which concerns on 1st Embodiment. It is a horizontal sectional view showing the composition of the nuclear reactor system concerning a 2nd embodiment. It is a horizontal sectional view showing a modification of composition of a nuclear reactor system concerning a 2nd embodiment. It is an elevation sectional view showing an example of composition of a conventional fuel exchange system. It is an elevation sectional view showing an example of composition of a conventional reactor system of a small fast reactor. It is a horizontal sectional view which shows the example of a structure of the reactor system of the conventional small fast reactor.

  Hereinafter, a fast reactor fuel exchange system and a nuclear reactor system according to an embodiment of the present invention will be described with reference to the drawings. Here, the same or similar parts are denoted by common reference numerals, and redundant description is omitted.

[First Embodiment]
FIG. 1 is a cross-sectional view taken along the line I-I in FIG. 3 illustrating a configuration of the nuclear reactor system according to the first embodiment during fuel replacement. FIG. 2 is a sectional view taken along the line II-II in FIG. 3 showing the configuration of the nuclear reactor system according to the first embodiment at the time of fuel replacement. FIG. 3 is a horizontal sectional view taken along the line III-III in FIG. 1 showing the configuration of the nuclear reactor system according to the first embodiment during fuel replacement.

  The nuclear reactor system 100 includes a core 2, a nuclear reactor vessel 10, a shielding plug 11, a reflector 5, an intermediate heat exchanger 16, an electromagnetic pump 17, a guard vessel 12, a top dome 13, and a fuel exchange system 50.

  As shown in FIG. 3, the core 2 includes a plurality of fuel assemblies 1 that are arranged in a hexagonal lattice shape in the horizontal direction and that each outer shape is a hexagonal column and extends in the vertical direction. As shown in FIGS. 1 and 2, the fuel assembly 1 is mounted on the core support 6b via the flow adjustment module 6c for flow distribution. The core support base 6 b has a cylindrical shape whose axis is the vertical direction, and the lower part is supported by the core support plate 6. The core support plate 6 has a horizontally extending disk shape, and its periphery is coupled to the inner wall of the reactor vessel 10 and is supported by the reactor vessel 10. The core support plate 6 has a plurality of reactor coolant flow holes for cooling that are communicated with the core support 6b at the inlet of the fuel assembly 1 provided above, the reflector 5 described later, and the relay part 21 in the reactor vessel. Is formed.

  The nuclear reactor vessel 10 has a cylindrical shape having a mirror plate in the lower portion with the axis as a vertical direction, and the upper portion is open. The shielding plug 11 has a radiation shielding function that blocks the opening at the top of the reactor vessel 10 and reduces the radiation level in the space above the shielding plug 11. A reactor coolant 3 a for cooling the reactor core 2 is accommodated in the reactor vessel 10. The reactor coolant 3a is, for example, a liquid metal. Examples of the liquid metal include sodium. Further, a cover gas 3b is accommodated in a sealed space formed by the reactor vessel 10 and the shielding plug 11 above the reactor coolant 3a, that is, an upper space of the reactor coolant 3a.

  The guard vessel 12 is provided so as to cover the side surface and the outside of the bottom surface of the reactor vessel 10. The top dome 13 is provided so as to cover the side surface and the upper portion of the shielding plug 11. The guard vessel 12 and the top dome 13 are connected to each other and constitute a sealed space as a storage barrier. The top dome 13 is surrounded by the reactor building 300.

  Inside the reactor vessel 10 outside the radial direction of the core 2, a cylindrical core tank 4 having an open top and bottom is provided so as to surround the core 2. A plurality of reflectors 5 are provided in an annular space inside the partition wall 7, which will be described later, outside the core tank 4 in the radial direction. The reflectors 5 have a partial arc shape in the horizontal section and extend vertically, and are arranged with a gap in the circumferential direction. The reflector 5 has a function of controlling the reactivity level of the core 2 by returning neutrons leaking from the core 2 to the core 2 side. A neutron detector 19 is arranged between the reflectors 5 adjacent to each other.

  Above the reflector 5, a reflector upper shielding body 5c provided adjacent to the reflector 5, a reflector 5 and a reflector driving mechanism 5a for driving the reflector upper shielding body 5c up and down, and reflector driving A reflector drive shaft 5b that connects the mechanism 5a and the reflector 5 is provided. The reflector drive shaft 5b coupled to the reflector 5 can drive the reflector upper shield 5c together with the reflector 5 by passing through the central axis of the reflector upper shield 5c. As shown in FIG. 3, a plurality of reflector upper shielding bodies 5c and reflector drive shafts 5b penetrating therethrough are arranged in the circumferential direction.

  On the outer side in the radial direction of the reflector 5, a partition wall 7 having a cylindrical shape that extends vertically and is open at the top and bottom is provided. The lower part of the partition wall 7 is connected to the core support plate 6, and the partition wall 7 is supported by the core support plate 6. The upper end of the partition wall 7 is at a position lower than the liquid level of the reactor coolant 3a. The partition wall 7 forms an outer annular portion 15 between the inner wall of the reactor vessel 10.

  The outer annular portion 15 includes a plurality of cylindrical intermediate heat exchangers 16 having a vertical axis and a plurality of cylindrical electromagnetic pumps 17 having a vertical axis as a built-in pump (FIGS. 2 and 3). ) Is arranged. As shown in FIG. 3, the intermediate heat exchanger 16 and the electromagnetic pump 17 are disposed in the outer annular portion 15 so as to be spaced apart from each other in the circumferential direction.

  The plurality of intermediate heat exchangers 16 and the plurality of electromagnetic pumps 17 are provided substantially in parallel in this arrangement, but the intermediate heat exchanger 16 and the electromagnetic pump 17 are connected in series as flow paths. Thus, a partition (not shown) is provided in the outer annular portion 15. That is, the reactor coolant 3a rising from the core 2 changes the direction of the upper part of the partition wall 7 to the outside in the radial direction and then descends the outer annular portion 15 and flows into the intermediate heat exchanger 16. The reactor coolant 3 a that has flowed out of the intermediate heat exchanger 16 flows into the electromagnetic pump 17, flows out of the electromagnetic pump 17, and then passes through the neutron shield 8 provided in the lower region of the outer annular portion 15. Then, it reaches the lower part of the reactor vessel 10 and flows into the reactor core 2 again.

  The fuel exchange system 50 includes a fuel handling machine 30, a reactor vessel relay section 21, and a fuel inlet / outlet section 40. The fuel handling machine 30 is installed prior to the fuel exchange when the nuclear reactor is stopped, and is removed after the fuel exchange is completed. The fuel handling machine 30 includes a drive unit 31 mounted on the shielding plug 11, a central shaft body 32 connected to the drive unit 31, a hold-down tube 33, a main arm 34, and an auxiliary arm 35.

  The drive unit 31 is provided so as to penetrate the opening formed in the top dome 13. Prior to installation of the drive unit 31, the furnace stop rod drive mechanism 9 and the fuel handling machine penetrating portion lid 13a (see FIG. 4) are removed.

  The central shaft body 32 is provided in the vertical position when viewed from the center of the core 2 where the reactor stop rod 9a is placed, that is, the space position after the reactor stop rod drive mechanism 9 is removed, and passes through the shielding plug 11. Then, it extends to the upper center in the radial direction of the core 2, and is connected to the drive unit 31 so as to be movable up and down and to be rotatable.

  The hold down tube 33 extends vertically upward. The hold-down tube 33 incorporates a gripper (not shown) that can be coupled to the transfer target fuel assembly 1a (see FIG. 5) that is the transfer target and that can separate the transfer target fuel assembly 1a. When gripping the transfer target fuel assembly 1a, the gripper extends downward from the hold-down tube 33 and is coupled to the transfer target fuel assembly 1a. The gripper is pulled upward while being coupled to the transfer target fuel assembly 1 a, and the transfer target fuel assembly 1 a is stored in the hold-down tube 33. The central shaft body 32 and the hold-down tube 33 are coupled to each other by a main arm 34 and an auxiliary arm 35 provided in parallel with the main arm 34. Each coupling part is formed to be rotatable.

  The hold down tube 33, the central shaft body 32, the main arm 34, and the auxiliary arm 35 constitute a parallelogram link. While maintaining the upright posture of the hold-down tube 33 by this parallelogram link, the main arm 34 and the auxiliary arm 35 can move in the radial direction above the core 2 by increasing or decreasing the angle with respect to the vertical direction. Further, by combining with the vertical movement of the central shaft body 32, it is possible to move in the radial direction above the core 2 while maintaining a constant gap with the upper portion of the core 2.

  Further, the hold-down tube 33 rotates in the circumferential direction by the rotation of the central shaft body 32. As a result, the holddown tube 33 can access any position of the core 2. The position of the in-furnace relay section 21 can also be accessed.

  As shown in FIG. 1, the reactor vessel relay portion 21 is adjacent to the reflector 5 on the radially outer side of the reactor vessel 10. In plan view, as shown in FIG. 3, it is disposed at a position where it has bitten into the region of the outer annular portion 15 where the intermediate heat exchanger 16 and the electromagnetic pump 17 are disposed. Therefore, the partition wall 7 that divides the region in which the reactor coolant 3 a provided with the reflector 5 ascends and the outer annular portion 15 in which the reactor coolant 3 a descends is provided around the reactor vessel relay portion 21. Only this part forms a partition protrusion 22 having a shape that bites into the outer annular portion 15 side. That is, the in-furnace relay section 21 belongs to the area inside the partition wall 7. When the center of the hold-down tube 33 is overlapped with the center of the in-furnace relay part 21 in a plan view, the inside of the bulkhead protrusion 22 on the side of the relay part 21 in the furnace container, that is, the inside of the bulkhead protrusion 22 is The size does not interfere with the outside of 33.

  The fuel inlet / outlet portion 40 has a shield plug entrance / exit opening portion 42 formed in the shield plug 11 and penetrating in the vertical direction. The shielding plug entrance / exit opening 42 is formed immediately above the in-furnace relay section 21. As will be described later with reference to FIG. 4, the shielding plug access opening 42 is closed by a fuel access hole plug 46 except when the fuel of the nuclear reactor system 100 is changed.

  As shown in FIG. 1, the fuel inlet / outlet section 40 further includes an inlet / outlet door valve 41, an inlet / outlet guide pipe 43, and a traveling fuel inlet / outlet machine 44 that are installed at the time of fuel replacement. Note that the traveling fuel injector 44 can travel on a floor (not shown) above the top dome 13. The entrance / exit guide tube 43 is formed in a circular tube shape whose upper and lower sides are opened with the vertical direction as an axis, and is supported by the shielding plug 11 while vertically penetrating the shielding plug entrance / exit opening 42. The entrance / exit guide tube 43 may be supported by the entrance / exit door valve 41.

  The door valve 41 for entering / exiting is in the path | route where the transfer object fuel assembly 1a enters / exits, and closes when not entering / exiting, and forms an entrance / exit passage when entering / exiting. In the lower part of the door valve 41 for access, a connecting cylinder part that can be mounted on the reactor building 300 is formed. Moreover, the upper surface of the door valve 41 for entrance / exit has a horizontal flat shape. The traveling fuel inlet / outlet machine 44 is connected to the upper surface of the door valve 41 for entry / exit when the transfer target fuel assembly 1a is transferred.

  The traveling fuel loading / unloading machine 44 suspends the loading / unloading gripper 45 downward. When the transfer target fuel assembly 1a taken out from the core 2 is transferred, the input / output gripper 45 stores the transfer target fuel assembly 1a in a fuel transfer pot 23 (see FIG. 5), which will be described later. 23. In addition, when the new fuel is transferred as the transfer target fuel assembly 1a from above the shielding plug 11 into the reactor vessel 10, the transfer target fuel assembly is also used to return the fuel transfer pot 23 into the reactor core 2. The fuel transfer pot 23 is handled in a state where the la is stored in the fuel transfer pot 23. The entrance / exit gripper 45 is guided by the entrance / exit guide tube 43 when moving up and down.

  4 is a sectional view taken along the line IV-IV in FIG. 3 showing a configuration during normal operation of the nuclear reactor system according to the first embodiment. Hereinafter, description will be given with reference to FIG. In the center of the shielding plug 11, a fuel handling machine 30 is installed at the time of fuel exchange, but during normal operation of the nuclear reactor system 100, the fuel handling machine 3 is removed and the reactor stop rod driving mechanism is located at the traced space position. 9 is provided. The reactor stop rod drive mechanism 9 connects the reactor stop rod 9a to the lower portion, and if an abnormality occurs in the reactor system 100, the reactor stop rod 9a is disconnected and the reactor stop rod 9a can be dropped downward. It is in a standby state. At the time of fuel replacement, the furnace stop rod 9a is separated from the furnace stop rod drive mechanism 9 and is placed in the core 2.

  As for the fuel inlet / outlet portion 40, a fuel transfer pot 23 (FIG. 5) is placed in the in-furnace relay portion 21, and a pot shielding body 23c is inserted into the fuel transfer pot 23 to perform the shielding function. Secured. In addition, a fuel inlet / outlet plug 46 is installed in the opening / outlet portion 42 for the shield plug formed in the shield plug 11 to ensure airtightness and a shielding function.

  A fuel handling machine penetration part lid 13 a is attached to the fuel handling machine penetration opening 39 of the top dome 13. A top dome access opening lid 13 b is attached to the top dome access opening 47 of the top dome 13. As a result, the airtight function of the top dome 13 is ensured.

  FIG. 5 is an enlarged vertical sectional view showing a part of the fuel exchange system in the nuclear reactor system according to the first embodiment. FIG. 6 is a horizontal sectional view taken along the line VI-VI in FIG. 1 showing the configuration of the nuclear reactor system according to the first embodiment.

  The in-furnace relay section 21 is mounted on the core support plate 6 and has a cylindrical shape that extends vertically with the top and bottom open. For this reason, as shown in FIG. 5, the transfer target fuel assembly 1 a and the fuel transfer pot 23 can stand on the core support plate 6. The in-furnace relay section 21 is not necessarily limited to a cylindrical shape. For example, it may be a cradle shape made of a frame material or a cylindrical container shape.

  A cooling hole 21 a that guides the reactor coolant 3 a from below into the in-reactor relay unit 21 is formed in a portion of the core support plate 6 below the in-reactor relay unit 21. The cooling hole 21a has a function of adjusting the flow rate of the reactor coolant 3a guided to the reactor vessel relay section 21.

  A guide part 24 is provided above the in-furnace relay part 21. The guide portion 24 is supported by the partition wall 7 or the partition wall protruding portion 22. The guide portion 24 has a cylindrical shape, the upper and lower sides are opened, the lower end has an annular horizontal cross section, and the center thereof is on the same vertical line as the center of the in-furnace relay portion 21. It gradually spreads upward from this lower end. The upper end is substantially in contact with the inner surface of the partition protrusion 22.

  The fuel transfer pot 23 has an upper cylinder 23a and a lower cylinder 23b. The upper cylinder 23a has, for example, a cylindrical shape that extends vertically and is open at the top and bottom. The lower cylinder 23b has, for example, a cylindrical shape having a diameter smaller than that of the upper cylinder 23a and opened up and down. The lower cylinder 23b is concentrically connected to the lower part of the upper cylinder 23a via a frustoconical connection.

  The inner diameter of the upper cylinder 23a of the fuel transfer pot 23 has an inner diameter that can accommodate the transfer target fuel assembly 1a. The lower cylinder 23b of the fuel transfer pot 23 has an inner diameter that can accommodate the nozzle portion 1b of the transfer target fuel assembly 1a. For this reason, the fuel transfer pot 23 can accommodate the transfer target fuel assembly 1a in a state where the nozzle portion 1b of the transfer target fuel assembly 1a is inserted into the lower cylinder 23b. The upper cylinder 23a and the lower cylinder 23b may be polygonal cylinders.

  Also. When the fuel transfer pot 23 is placed on the in-furnace relay part 21, the upper end of the fuel transfer pot 23 is formed to be higher in the vertical direction than the lower end of the guide part 24. For this reason, the guide portion 24 serves as a guide for transferring the transfer target fuel assembly 1a from above onto the in-furnace relay unit 21 and the fuel transfer pot 23 is placed on the in-furnace relay unit 21. It has a function to prevent the fuel transfer pot 23 from falling over.

  FIG. 7 is a flowchart showing the procedure of the fuel exchange method in the nuclear reactor system according to the first embodiment. In the nuclear reactor system 100 in the present embodiment, when performing fuel exchange, first, the operation of the nuclear reactor is stopped (step S01).

  After step S01, the nuclear reactor system 100 is shifted to the configuration for refueling (step S02). Specifically, the fuel handling machine penetration part lid 13a and the top dome entrance / exit opening lid 13b of the top dome 13 are removed, the furnace stop rod drive mechanism 9 is removed, the fuel inlet / outlet plug 46 is removed, and the fuel handling machine 30 is installed. The door valve 41 for entry / exit and the entrance / exit guide pipe 43 are installed, and the pot shield 23c is removed from the fuel transfer pot 23. In addition, the fuel storage portion of the traveling fuel inlet / outlet machine 44 is connected to the upper surface of the door valve 41 for entrance / exit.

  In the nuclear reactor system 100 according to the present embodiment, the top dome 13 is provided with the fuel handling machine penetrating portion lid 13a and the top dome entrance / exit lid 13b, so that the top dome 13 itself is prepared for fuel replacement. There is no need to remove it.

  After step S02, the spent fuel assembly, which is the transfer target fuel assembly 1a, is transferred from the core 2 by the fuel handling machine 30 into the fuel transfer pot 23 installed on the in-furnace relay section 21 (step). S03). At this time, the hold down tube 33 of the fuel handling machine 30 directly handles the transfer target fuel assembly 1a.

  Since the fuel handling machine 30 can access each place on the core 2 and the relay part 21 in the reactor vessel, the fuel assembly loaded in any location in the reactor core 2 can also be connected to the relay part 21 in the reactor vessel. Can be transferred to. Since the reactor vessel relay section 21 is provided inside the partition wall 7, the fuel handling machine 30 is disposed between the reactor core 2 and the reactor container relay section 21 in the region surrounded by the partition wall 7 in the reactor vessel 10. Can be transferred. In the reactor internal relay section 21, the reactor coolant rises from the cooling holes 21 a formed in the core support plate 6. Further, since a flow path is formed in the fuel transfer pot 23 from the lower opening of the lower cylinder 23b to the upper opening of the upper cylinder 23a, cooling of the spent fuel as the transfer target fuel assembly 1a is ensured. Is done.

  After step S03, the input / output gripper 45 is lowered from the traveling fuel input / output machine 44 to the fuel transfer pot 23. The fuel transfer pot 23 containing the spent fuel assembly as the fuel assembly 1a to be transferred is gripped by the entrance / exit gripper 45, the fuel transfer pot 23 is raised, and the inside of the entrance / exit guide pipe 43 and the inside / outside door valve 41 are passed through, The vehicle is stored in the traveling fuel injector 44 (step S04). The door valve 41 for entrance / exit, the entrance / exit guide pipe 43 and the relay part 21 in the furnace vessel are arranged in the vertical direction. Further, since the guide portion 24 is provided at the height between the entrance / exit guide tube 43 and the in-furnace relay unit 21, when the fuel transfer pot 23 descends, it is directly above the in-furnace relay unit 21. Smooth transfer. Further, when the fuel transfer pot 23 reaches the in-furnace relay section 21, the guide section 24 holds the upper end of the fuel transfer pot 23, so that the fuel transfer pot 23 is stable and the in-furnace relay section. 21 will be placed.

  After step S04, the new fuel assembly, which is the new transfer target fuel assembly 1a, stored in the traveling fuel take-in / out machine 44 is stored in the fuel transfer pot 23. Further, the fuel transfer pot 23 storing the new fuel as the transfer target fuel assembly 1a is grasped by the entrance / exit gripper 45 and lowered through the entrance / exit door valve 41 and the entrance / exit guide pipe 43 to the inside of the reactor vessel relay section 21. Transfer (step S05).

  After step S05, the fuel handling machine 30 holds the new fuel assembly that is the transfer target fuel assembly 1a in the fuel transfer pot 23 placed on the in-furnace relay section 21. Further, the fuel handling machine 30 takes out the new fuel, which is the transfer target fuel assembly 1a, from the fuel transfer pot 23, and loads it in the core 2 where the used spent fuel assembly was loaded (step S06). ).

  After step S06, it is determined whether or not all the fuel assemblies that have been scheduled for fuel replacement have been replaced (step S07). If the planned fuel assembly replacement is still left (NO in step S07), steps S03 to S07 are repeated.

  Each time the spent fuel assembly is taken out and the new fuel assembly is loaded, the traveling fuel take-in unit 44 is used between the spent fuel assembly and the storage location (not shown) of the new fuel assembly. Transfer spent fuel assemblies and new fuel assemblies.

  If it is determined that fuel replacement has been completed for all scheduled fuel assemblies (YES in step S07), the reactor system 100 is shifted to a configuration that allows normal operation (step S08). Specifically, the insertion of the pot shield 23c into the fuel transfer pot 23, the removal of the fuel handling device 30, the removal of the door valve 41 for loading / unloading, and the loading / unloading guide tube 43, the fuel handling device penetrating portion lid 13a of the top dome 13 and Installation of the top dome access opening cover 13b, installation of the furnace stop rod drive mechanism 9, installation of the fuel access hole plug 46, and the like are performed.

  As described above, according to the fuel exchange system 50 of the nuclear reactor system 100 according to the present embodiment, the fuel exchange function can be ensured while the reactor vessel 10 is made compact.

[Second Embodiment]
FIG. 8 is a horizontal sectional view showing a configuration of a nuclear reactor system according to the second embodiment. This embodiment is a modification of the first embodiment. Although the central shaft body 32 of the fuel handling machine 30 in the first embodiment is provided immediately above the center of the core, the central shaft body 32 of the fuel handling machine 30 in the second embodiment is a relay section in the reactor vessel. The fuel handling machine 30 is provided in the partition wall protruding portion 22 at a position inside the partition wall protruding portion 22 and adjacent to the partition wall protruding portion 22. The hold-down tube 33 of the fuel handling machine 30 in this embodiment can also access the position of the farthest fuel assembly in the core 2.

  In this way, by providing the fuel handling machine 30 on the radially outer side of the reactor vessel from the region where the reflector 5 is provided, the fuel handling machine 30 is provided above the core 2 in the normal operation state of the reactor. Will not interfere with the equipment being used. For this reason, it becomes possible to install the fuel handling machine 30 permanently. As a result, the work related to the removal of the furnace stop rod drive mechanism 9 and the installation of the fuel handling machine 30 for the configuration of the fuel exchange state before the fuel exchange is eliminated. Further, there is no need for work related to the removal of the fuel handling machine 30 and the installation of the reactor stop rod drive mechanism 9 for the configuration in which the reactor can be normally operated after the fuel replacement.

  Thus, in the nuclear reactor system according to the second embodiment, in addition to the effects in the nuclear reactor system according to the first embodiment, there is an effect that the steps required at the time of fuel replacement are further shortened.

  FIG. 9 is a horizontal sectional view showing a modification of the configuration of the nuclear reactor system according to the second embodiment. In the present embodiment, the fuel handling machine 30 is provided inside the partition wall protruding portion 22, which is different from the in-furnace relay portion 21.

  In this modification, the same effect as that of the second embodiment can be obtained. In addition, the width of the combination of the circumferential position of the fuel handling machine 30 and the circumferential position of the in-reactor container relay portion 21 is widened, and since it is compact, a high degree of freedom can be secured in the layout design of the reactor system 100 that is severe.

[Other Embodiments]
As mentioned above, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. For example, in the embodiment, the case of a small fast reactor has been described, but the present invention is not limited to a small fast reactor. The present invention can be applied to a tank type fast reactor, that is, a reactor system in which a primary cooling system is provided in the same reactor vessel. Moreover, although the case where an electromagnetic pump was used as a built-in pump was shown in embodiment, a mechanical pump can also be used.

  The configuration of the present invention is also effective for moving to another part of the core via the in-reactor relay section 21 when the fuel in the core 2 is shuffled.

  Each embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 1 ... Fuel assembly, 1a ... Fuel assembly to be transferred, 1b ... Nozzle part, 2 ... Core, 3a ... Reactor coolant, 3b ... Cover gas, 4 ... Core tank, 5 ... Reflector, 5a ... Reflector drive Mechanism, 5b ... Reflector drive shaft, 5c ... Reflector upper shield, 6 ... Core support plate, 6b ... Core support, 6c ... Flow control module, 7 ... Bulkhead, 8 ... Neutron shield, 9 ... Reactor stop rod Drive mechanism, 9a ... reactor stop rod, 10 ... reactor vessel, 11 ... shield plug, 12 ... guard vessel, 13 ... top dome, 13a ... fuel handling machine penetration cover, 13b ... top dome access opening / closing cover, 15 ... Outer annular part, 16 ... intermediate heat exchanger, 17 ... electromagnetic pump (built-in pump), 18 ... reactor pedestal, 19 ... neutron detector, 21 ... reactor vessel relay part, 21a ... cooling hole, 22 ... bulk protruding part 23 ... Fuel transfer pot, 23a ... Upper part , 23b ... Lower cylinder, 23c ... Pot shield, 24 ... Guide part, 30 ... Fuel handling machine, 31 ... Drive part, 32 ... Center shaft, 33 ... Hold down tube, 34 ... Main arm, 35 ... Auxiliary arm 39 ... Fuel handling machine through opening, 40 ... Fuel inlet / outlet part, 41 ... Door valve for entry / exit, 42 ... Opening part for shield plug entry / exit, 43 ... Entrance / exit guide pipe, 44 ... Traveling fuel entry / exit machine, 45 ... Entrance / exit gripper, 46 DESCRIPTION OF SYMBOLS ... Fuel access port plug, 47 ... Top dome access opening, 50 ... Fuel exchange system, 100 ... Reactor system, 201 ... Roof deck, 202 ... Bulkhead, 210 ... Variable arm type fuel handling machine, 211 ... Fuel handling machine body , 212 ... arm, 213 ... hold-down tube, 220 ... in-furnace relay device, 221 ... door valve for access, 222 ... in-furnace relay tank, 251 ... annular intermediate heat exchange Vessel, 252 ... annular electromagnetic pump, 300 ... reactor building

Claims (9)

A fast reactor core having a plurality of fuel assemblies arranged parallel to each other and extending vertically,
A cylindrical reactor vessel that houses the cover gas that covers the core, the reactor coolant, and the top of the reactor coolant, and that opens up and extends up and down,
A core support plate that is supported by the reactor vessel in the reactor vessel and extends in the horizontal direction to support the core;
A shielding plug covering the top of the reactor vessel;
A cylindrical core tank having an open top and bottom that is provided around the radial direction of the core in the reactor vessel and protects the core;
A plurality of reflectors, which are provided in the reactor vessel so as to surround the reactor core as a whole outside in the radial direction of the reactor tank and which can move up and down to reflect neutrons generated in the reactor core and control the reactivity; ,
The reactor vessel is provided outside the reflector in the radial direction, and the reactor coolant ascends in the core and the reactor coolant is folded back radially outward above the core. A substantially cylindrical partition wall that extends up and down and separates from the outer annular portion, which is a rear outer channel, and is open at the top and bottom, forming a partition protrusion that protrudes radially outward and extends to the upper end of the partition wall. A partition wall,
A plurality of intermediate heat exchangers provided at intervals in the circumferential direction of the outer annular portion;
A plurality of built-in pumps that are spaced apart from each other in the circumferential direction of the outer annular portion and circumferentially spaced from the intermediate heat exchanger to circulate the reactor coolant in the reactor vessel;
A reactor stop rod for stopping the reaction in the reactor core;
A furnace stop rod drive mechanism for driving the furnace stop rod;
At the time of fuel replacement, the transfer target fuel assembly, which is the transfer target among the fuel assemblies in the core, is transferred out of the reactor vessel from the core, and a new fuel assembly is used as the transfer target fuel assembly. A fuel exchange system for transferring to the core from outside the reactor vessel;
A nuclear reactor system comprising:
The fuel change system includes:
An in-furnace relay section that is provided in the partition protrusion and is capable of temporarily placing the transfer target fuel assembly;
A fuel handling machine for transferring the fuel assembly to be transferred between the reactor core and the relay part in the reactor vessel in the reactor vessel at the time of the fuel exchange;
When the fuel is changed, the shield plug has an opening portion for opening and closing the transfer plug of the transferable fuel assembly that is openable and closable formed in a portion immediately above the relay portion in the reactor vessel in the shield plug. A fuel inlet / outlet part that allows the transfer target fuel assembly to be transferred between a relay part and the outside of the reactor vessel;
A nuclear reactor system characterized by comprising: The fuel inlet / outlet portion includes an entrance / exit door valve for containing the cover gas when the transfer target fuel assembly is transferred,
When the fuel is changed, the transfer target fuel assembly is transported up and down with the upper surface of the door valve for entrance and exit and the relay part in the furnace vessel, and the transfer target fuel assembly is stored in the state where the transfer target fuel assembly is stored. A traveling fuel injector that can move horizontally outside the reactor vessel;
The reactor system according to claim 1, further comprising: The fuel handling machine is
A drive unit mounted on the shielding plug;
A central shaft body that is provided below the drive unit and connected to the drive unit, extends through the shielding plug and extends downward, and is movable up and down and rotatable.
A hold-down tube that is formed so as to be capable of being coupled to and detached from the transfer target fuel assembly and extends in the vertical direction;
A main arm that rotatably couples the central shaft body and the hold-down tube;
An auxiliary arm provided in parallel with the main arm and rotatably connecting the central shaft body and the hold-down tube;
The nuclear reactor system according to claim 1 or 2, wherein   The holddown tube is configured to increase or decrease the angle of the main arm and the auxiliary arm with respect to the vertical direction and maintain the center while maintaining an upright posture by a parallelogram link configured together with the central shaft body, the main arm, and the auxiliary arm. 4. The atom according to claim 1, wherein the atom expands and contracts in a radial direction directly above the core by the vertical movement of the shaft body, and rotates in the circumferential direction by the rotation of the central shaft body. Furnace system. The fuel change system further includes a fuel transfer pot capable of storing the transfer target fuel assembly,
The in-furnace relay section is capable of temporarily placing the fuel transfer pot containing the transfer target fuel assembly.
The transfer target fuel assembly transferred by the in-furnace relay device is accommodated in the fuel transfer pot and is transferred together with the fuel transfer pot at the fuel inlet / outlet part.
The nuclear reactor system according to any one of claims 1 to 4, wherein   A guide part serving as a guide for transferring the transfer target fuel assembly is provided above the relay part in the reactor vessel, and the guide part is opened up and down and gradually spreads upward. The nuclear reactor system according to any one of claims 1 to 5, wherein:   The nuclear reactor system according to any one of claims 1 to 6, wherein the fuel handling machine is provided immediately above a central portion of the core.   7. The fuel handling machine according to claim 1, wherein the fuel handling device is provided inside the partition protrusion and directly above a position surrounded by the partition protrusion. 8. Nuclear reactor system. A core of a fast reactor including a plurality of fuel assemblies, a reactor vessel containing the core, a shielding plug covering an upper portion of the reactor vessel, a reactor core tank provided around the reactor core, and the reactor core tank; A plurality of reflectors provided to surround the reactor core as a whole on the radially outer side, a partition wall provided on the radially outer side of the reflector body, and an outer annular portion on the radially outer side of the partition wall. A reactor system comprising a plurality of intermediate heat exchangers and a plurality of built-in pumps, wherein a fuel assembly to be transported among the fuel assemblies in the core at the time of fuel exchange is transferred from the core. A fuel exchange system for transferring a fuel assembly outside the reactor vessel and transferring a new fuel assembly as the transfer target fuel assembly from the outside of the reactor vessel to the core,
The partition is formed with a partition protrusion that protrudes radially outward and extends to the upper end of the partition,
An in-furnace relay section that is provided inside the partition protrusion and is capable of temporarily placing the transfer target fuel assembly;
A fuel handling machine that transfers the fuel assembly to be transferred that is in the reactor vessel at the time of the fuel exchange and is to be transferred between the core and the relay portion in the reactor vessel;
In the fuel exchange, the furnace vessel has an opening portion for opening / closing the plug for transfer of the transferable fuel assembly that can be opened and closed formed in a portion directly above the relay portion in the reactor vessel in the shield plug. A fuel inlet / outlet part that enables transfer of the transfer target fuel assembly between an inner relay part and the outside of the reactor vessel;
A fuel exchange system comprising:

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