JP5279192B2 - Fast reactor - Google Patents

Description

  The present invention relates to a reactivity control facility and a fast reactor using the same.

  An example of a conventional fast reactor is disclosed in Patent Document 1. As shown in FIG. 10, the structure of such a fast reactor has a core 2 composed of an assembly of nuclear fuels. The core 2 is formed in a substantially cylindrical shape as a whole, and is formed by a core tank 3 that protects the core 2. Surrounded by the outer periphery. An annular reflector 4 that surrounds the core 3 is disposed outside the core 3. A partition wall 6 is provided outside the reflector 4 so as to surround the reflector 4 and constitute the inner wall of the flow path of the primary coolant. A reactor vessel 7 constituting the outer wall of the coolant flow path is disposed outside the partition wall 6 with a space therebetween. A neutron shield 8 is disposed in the coolant channel so as to surround the core 2.

A hexagonal tubular wrapper tube is arranged at the center of the core, and a cylindrical reactor stop rod and a fan-shaped neutron absorber divided into six parts are enclosed in the wrapper tube. The reactor stop rod becomes a back-end reactor shutdown system for the reflector that performs the main reactor shutdown function, and the neutron absorber suppresses the reactivity when the initial excess reactivity is large. Of these drive systems, the furnace stop rod drive mechanism consists of a drive unit and an upper guide tube, and connects the furnace stop rod under the upper guide tube to drive up and down during normal operation and scram function during an emergency. It has a function to separate and hold the furnace stop rod before restarting. The neutron absorber driving mechanism is composed of an operating shaft and a holding mechanism. The neutron absorber driving mechanism holds the neutron absorber only once during the life of the plant and individually holds it up to the upper limit.
Japanese Patent No. 3126524

In a fast reactor based on reflector control, a reactor stop rod drive mechanism of a post-furnace shutdown system and a neutron absorber drive mechanism that suppresses the initial excess reactivity are required. However, the reactor top reflector drive mechanism, the liquid level meter furnace, and various measuring instruments such as a furnace thermometer is mounted, wherein the drive mechanism has to be installed in a limited space.

  In addition, the fast reactor with reflector control allows continuous operation for a long period of time, and it is required to reduce maintenance for operating equipment that is always installed, and a backup operating mechanism is necessary in the event of a failure. It becomes. In particular, in the furnace stop rod drive mechanism, it is desirable to provide a backup scrum mechanism for safety considerations.

  On the other hand, the neutron absorber driving mechanism needs to be provided adjacent to the furnace stop rod, and a compact arrangement by simplifying the mechanism is indispensable.

  The object of the present invention is to achieve high performance and high reliability by suppressing the reactivity when the initial excess reactivity is large, and further realizing the multiplexing of the furnace stop rod scram function with a simple mechanism and a compact arrangement. It is an object of the present invention to provide a reactivity control facility and a fast reactor using the reactivity control facility.

A fast reactor according to an embodiment of the present invention includes a plurality of fuel assemblies constituting a core, a reactor stop rod of a post-furnace stop system, and an initial arrangement disposed around the periphery of a hexagonal tubular trumpet at the center of the core A reactivity control assembly containing a plurality of neutron absorbers that suppress excess reactivity of the reactor, a reactor core that surrounds the outer periphery of the core, a reflector that surrounds the periphery of the reactor core, and moves up and down, A partition wall that surrounds the outer periphery and forms an inner wall of the coolant channel of the primary coolant, an upper support plate that supports the core tank and the partition wall, and an intermediate heat exchange that is installed in an annular space above the upper support plate And an electromagnetic pump disposed at a lower portion of the intermediate heat exchanger, and the fuel assembly, the reactivity control assembly, the reflector, the partition, the intermediate heat exchanger and the electromagnetic pump are accommodated, and an upper opening is provided. A reactor vessel and the reactor vessel An upper plug for closing the section opening, a drive unit and an upper guide tube, outer extension tube and an inner extension pipe within the upper guide tube a double tube is disposed, is provided at the lowermost end of the outer extension tube is a gripper unit for holding detachably by the excitation of the holding magnet withdrawal or inserted as reactor shutdown rod upon reactivity control of the core, the inner extension by de-energized holding magnet during scram Yes and reactor shutdown rod drive mechanism for disconnecting the reactor shutdown rod in the gripper portion to drop the tube, is disposed around the reactor shutdown rod drive mechanism, the drive shaft of the double tube of the outer extension shaft and an inner extension shaft and, the above the lower end of the inner extension shaft gripper unit for the outer gripping neutron absorber upper handling head is configured to be provided, the outer extension shaft by pulling the inner side extension shaft at the gripping neutron absorbers And inserting the inner extension axis handling head of the neutron absorber, coupled with the neutron absorber wherein depress the outer extension shaft after reaching the handling head of the neutron absorber and gripping the outer latch fingers of the gripper portion A plurality of neutron absorber drive mechanisms that can individually move each neutron absorber up and down, and the reactor stop rod drive mechanism and the neutron absorber drive mechanism are integrated and arranged in the center of the upper plug. It is characterized by.

  According to the present invention, when the initial excess reactivity is large, the reactivity is suppressed, and further, a simple mechanism, a compact arrangement, and a high performance and high reliability that realizes multiplexing of the reactor stop rod scram function. A reactivity control facility and a fast reactor using the reactivity control facility can be provided.

  The best mode for carrying out the present invention will be described below with reference to FIGS. However, the same or similar parts as those in the prior art shown in FIG.

[First Embodiment]
FIG. 1 is a longitudinal sectional view of a fast reactor according to a first embodiment of the present invention. 2A and 2B are block diagrams of the reactivity control assembly having the furnace stop rod of FIG. 1, wherein FIG. 2A is a side view showing a part along A-A of FIG. 2B, and FIG. FIG. FIG. 3 is an enlarged longitudinal sectional view of the furnace stop rod drive mechanism of FIG.

  As shown in FIG. 1, the fast reactor 1 of the present embodiment mainly includes a core 2, a reactor core 3, a plurality of reflectors 4, a partition wall 6, a neutron shield 8, a reactor vessel 7, and a plurality of fuel assemblies 37. , The entrance module 38, the core support plate 13, the upper support plate 29, the intermediate heat exchanger 15, the electromagnetic pump 14, the reactivity control assembly 26, the upper plug 10, the guard vessel 9, and the storage dome 28.

  Each fuel assembly 37 is attached to an entrance module 38, and the entrance module 38 is attached to a core support 39. The core support base 39 is attached to the upper surface of the core support plate 13, and the core support plate 13 is attached to the reactor vessel 7.

  The primary coolant 5 is, for example, liquid metal sodium and circulates in the reactor vessel 7. That is, the primary coolant 5 is sent downward by the electromagnetic pump 14 disposed in the annular portion outside the partition wall 6 in the reactor vessel 7. Then, the primary coolant 5 enters the partition wall 6 from the bottom of the reactor vessel 7 and rises, and is heated through the core 2. Then, after further rising, the annular portion outside the partition wall 6 is lowered again, the intermediate heat exchanger 15 applies heat to the secondary coolant, and the electromagnetic pump 14 returns.

  The secondary coolant is, for example, liquid metal sodium, and flows into the reactor vessel 7 from the inlet nozzle 18, is heated by the intermediate heat exchanger 15, and then flows out of the reactor vessel 7 from the outlet nozzle 19. . The secondary coolant discharged from the outlet nozzle 19 is used as a heat source of a steam generator (not shown), for example.

  As shown in FIG. 2, the reactivity control assembly 26 at the center of the core 2 has a hexagonal tubular trumpet tube 200, a cylindrical reactor stop rod 51 disposed in the trumpet tube 200, and a six-division into its periphery. The fan-shaped neutron absorber 52 is arranged. The control element of the furnace stop rod 51 is one in which hafnium in the form of a single cylinder is placed in a stainless steel tube and sealed. The control element is sandwiched between upper and lower lattice plates 220 and fixed together with the protective tube 53 to form a furnace stop rod 51. The main body of the furnace stop rod 51 is a segment type divided into two upper and lower bodies.

  Further, the reactivity control equipment includes a hexagonal tube-shaped trumpet tube 200 at the center of the core 2, a reactor stop rod 51 of a post-furnace stop system disposed in the trumpet tube 200, and around the reactor stop rod 51. A reactivity control assembly 26 including a neutron absorber 52 that suppresses the divided initial excess reactivity is a main component. The furnace stop rod 51 has a handling rod 54 and a handling head 55 at the upper end of the handling rod 54 at the upper part of the protective tube 53, and is configured to be coupled to a gripper 56 at the lower end of the outer extension tube 67 of the furnace stop rod drive mechanism. The mechanism described later has a scram function that is pulled out / inserted when the fast reactor is started / stopped to control the reactivity, and is quickly inserted in an emergency to add a negative reactivity to the reactor and quickly stop it.

  The handling rod 54 and the upper part of the protective tube 53 are connected by a joint 203, and the insertion resistance force at the time of an earthquake can be absorbed by the displacement bent at the connecting portion together with the segment structure, and can be inserted smoothly. A dash ram 57 is provided at the bottom of the furnace stop rod 51 for buffering when the scram falls.

  The reactivity control assembly 26 is formed in a substantially hexagonal tube shape from the guide tube handling head 204 at the upper end to the entrance nozzle 205 at the lower end through the trumpet tube 200, and the upper and lower sides of the furnace stop rod 51 are in the center. A cylindrical lower guide tube 58 for guiding the operation is provided. Between the lower guide tube 58 and the trumpet tube 200, a fan-shaped neutron absorber 52 is divided into 6 parts. The neutron absorber 52 is made of hafnium, and the outside is covered with stainless steel. Unlike the reactor stop rod 51, the neutron absorber 52 does not have a scram function, and is usually fixed and provided for a long period of about 15 years from the beginning in order to absorb a relatively large excess reactivity of the initial core. After that, when the excess reactivity of the core decreases, it is pulled up from the core by a mechanism described later.

A cylindrical handling rod 201 is attached to the upper end of the neutron absorber 52. The upper end of the handling rod 201 protrudes slightly from the top of the reactivity control assembly 26 so that the tip can be gripped with a gripper. A neutron absorber handling head 60 having a bulge is provided. In addition, although the said reactivity control installation demonstrated the case where it applied to a fast reactor, it is applicable also to the reactivity control of the core of another nuclear reactor.

The furnace stop rod drive mechanism 27 includes a drive unit and an upper guide tube 66. Driver is mounted in a manner that self-supporting in the upper plug 10 top, the upper guide pipe 66 is mounted in a manner to be inserted through the opening hole of the upper portion plug 10 into the furnace. The driving of the furnace stop rod drive mechanism 27 is a motor-driven ball screw system that has high positioning accuracy and is compact in the radial direction. The twin ball screw 62 is rotated by the motor 61, and the extension pipes 67 and 68 are gripped by the ball nut 63. The latch mechanism 64 to be performed is moved up and down.

  The ball screw 62 is of a twin ball screw type in order to dodge the extension tube latch mechanism 64 disposed at the center. A cyclo reducer 65 is provided between the motor 61 and the ball screw 62, and when the fuel assembly 37 is replaced, the electromagnetic brake breaks down while the extension pipes 67 and 68 are pulled up in the furnace stop rod 51 delatched state. Also, the extension pipes 67 and 68 are prevented from falling off.

  In the vertical movement of the furnace stop rod 51, the vertical driving force of the drive unit is transmitted to the furnace stop rod 51 by the extension pipes 67 and 68 inside the upper guide pipe 66. The extension pipe is a double pipe of an outer extension pipe 67 and an inner extension pipe 68. When the furnace stop rod 51 is gripped (latched), the gripper 56 is inserted into the furnace stop rod handling head 55, and the latch finger 71 is This is done by exciting the holding magnet 70 in the drive section in the open state and pulling up the inner extension pipe 68 and the outer extension pipe 67 simultaneously.

  When the furnace stop rod 51 is separated (delatched), the holding magnet 70 in the drive section is de-energized and only the outer extension pipe 67 is pulled up. As a result, the outer extension pipe 67 moves to the upper side of the inner extension pipe 68, the latch finger 71 of the gripper 56 is closed, and the furnace stop rod handling head 55 is delatched.

  Next, the scram of the furnace stop rod drive mechanism will be described with reference to FIGS. 4A, 4B and 5. FIG.

  The scram method is a separate gravity drop type in which the furnace stop rod 51 and the extension pipes 67 and 68 are separated, and the furnace stop rod 51 is separated by the gripper 56 at the lowermost end of the outer extension pipe 67. From the viewpoint of fail-safe, when the holding magnet 70 in the drive mechanism is de-energized, the latch link 205 is opened and the inner extension pipe 68 is separated. In the scram, when the power of the holding magnet 70 is turned off, the inner extension pipe 68 falls slightly, the latch finger 71 holding the furnace stop rod handling head 55 is closed, and the furnace stop rod 51 falls by its own weight.

  In consideration of the case where the armature 72 does not fall and the inner extension pipe 68 does not descend for some reason, the rod 74 is pushed down by the backup delatching drive motor 73 to create a gap between the holding magnet 70 and the armature 72. A backup scrum mechanism is provided that breaks the suction balance of the holding magnet 70 and separates it. This operation can be a second scrum mechanism by providing a timer in the control circuit so that the normal holding magnet 70 is operated slightly behind the scram operation when the power is turned off.

  In order to detect the position of the furnace stop rod 51 during scrum, a permanent magnet 75 is embedded in the furnace stop rod handling head 55 and a coil 76 is attached to the upper guide tube 66 side. By measuring the electromotive force generated when the permanent magnet 75 passes through the coil 76, the position of the furnace stop rod 51 during scram can be detected.

  The upper guide tube 66 of the furnace stop rod drive mechanism fixes one end of a bellows 77 as a cover gas seal and the other is fixed to an outer extension tube 67. Further, a latch bellows 78 is provided between the outer extension pipe 67 and the inner extension pipe 68 for sealing. In consideration of any damage, a backup seal 79 of double V packing is provided in the drive mechanism. The upper guide tube 66 is installed in the CRD guide tube 206. The lower end of the upper guide tube 66 is inserted inside the furnace stop rod handling head 55 to perform positioning, holding, and seismic stabilization.

  Next, the neutron absorber driving mechanism will be described with reference to FIG.

  Six neutron absorber driving mechanisms are installed at equal intervals around the furnace stop rod driving mechanism in order to individually lift the six neutron absorbers 52. The operation of the neutron absorber drive mechanism is manual on-site. The drive shaft is a double tube with an inner extension shaft 80 and an outer extension shaft 81 offset in the middle. When the neutron absorber 52 is gripped, the inner extension shaft 80 is lifted by about 50 mm and both extension shafts 80 and 81 are moved to the neutron. It is inserted into the absorber handling head 60, and the handling shaft 60 of the neutron absorber 52 is gripped by the drive shaft latch mechanism 82 with a latch finger (not shown) of the gripper portion. Thereafter, only the outer extension shaft 81 is lowered to fix the latch fingers of the gripper portion.

  The lifting operation of the neutron absorber 52 is performed by removing the drive shaft support stopper 84 installed around the drive motor while holding the cover gas seal portion 83 of the double V packing and lifting the eyebolt 202. In the cover gas seal portion 83 on the upper surface of the upper plug 10, it is considered that sodium attached to the shaft in the cover gas space due to the drive shaft pulling up adheres to the seal and cannot maintain the sealing performance. For this reason, the entire drive unit outer housing 85 has a seal structure, and a backup seal 79 is provided at the top.

  In FIG. 1, reference numeral 11 denotes a reflector driving shaft that moves the reflector 4 up and down, reference numeral 24 denotes a rib, reference numeral 25 denotes a base, reference numeral 30 denotes a partition plate, and reference numeral 31 denotes a pedestal. .

  As described above, according to the first embodiment of the present invention, the furnace stop rod drive mechanism can realize a reliable drive system that achieves multiplexing of scram functions with a simple mechanism. Further, the driving mechanism of the neutron absorber 52 can be densely arranged with a simple mechanism in a narrow portion around the reactor stop rod drive mechanism, and a compact device combined with the reactor stop rod drive mechanism can be obtained.

[Second Embodiment]
A second embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the component same as or similar to 1st Embodiment, and the detailed description is abbreviate | omitted.

  In the first embodiment, as shown in FIG. 5, a backup scrum mechanism that pushes down the rod 74 by the backup delatching drive motor 73 of the furnace stop rod drive mechanism and separates the armature 72 is provided. On the other hand, in the second embodiment, as shown in FIG. 6, the outer extension pipe 67 is forcibly pushed up by a slight stroke to close the latch finger 71 that has gripped the furnace stop rod handling head 55, The furnace stop rod 51 is configured to drop by its own weight.

  The backup scrum mechanism is configured such that a power cylinder 86 provided in an extension pipe latch mechanism 64 that lifts the upper part of the outer extension pipe 67 pushes up the link mechanism of the outer extension pipe upper part 225, thereby causing the upper side of the inner extension pipe 68 to move upward. The link 205 of the latch mechanism is operated obliquely, thereby opening the inner extension tube latch link 215, the inner extension tube 68 falls by its own weight, and the latch finger 71 holding the furnace stop rod handling head 55. Is closed, and the furnace stop rod 51 is dropped by its own weight. Here, the power cylinder 86 is provided as an example of the push-up mechanism, but a hydraulic jack may be provided.

  As described above, according to the second embodiment of the present invention, the furnace stop rod drive mechanism can realize a reliable drive system that achieves multiplexing of scram functions with a simple mechanism.

[Third Embodiment]
A third embodiment of the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the component same as 1st Embodiment, and the detailed description is abbreviate | omitted.

  As shown in FIG. 7, the fast reactor 1 of the present embodiment has a coolant from the reactor core at the lower end of a protective cylinder 87 that covers the upper guide tube 66 of the reactor stop rod drive mechanism and the drive shaft of the neutron absorber 52. A rectifying plate 88 serving as a flow path is provided, and a gap larger than the amount of elongation due to swelling of the fuel assembly 37 is secured from the top level of the core 2 so as to suppress the lift of the fuel assembly 37 during an earthquake. It is a thing.

  During an earthquake, vertical vibrations are generated in addition to horizontal vibrations. As for the vertical direction, if the response acceleration in the core 2 exceeds 1G, an upward force exceeding its own weight may act on each fuel assembly 37, and it may float from a predetermined level. If the relative displacement with the rod 51 changes greatly, the reactivity control is seriously affected.

  The rectifying plate 88 at the lower end of the protective cylinder 87 is sized to project the corner portion of each core of the outermost layer. The thickness of the protective cylinder 87 is increased to increase the rigidity, and the strength against the collision force of the floating fuel assembly 37 is increased. Can be secured.

  As described above, according to the third embodiment of the present invention, it is possible to prevent the core 2 from being lifted during an earthquake, and it is possible to provide a fast reactor with high reliability.

[Fourth Embodiment]
A fourth embodiment of the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the component same as 1st and 2nd embodiment, and the detailed description is abbreviate | omitted.

As shown in FIGS. 8 and 9, in the fast reactor 1 of the present embodiment, it is necessary to provide an opening for replacing the fuel assembly 37 in the upper plug 10 at the time of initial criticality confirmation. The special hole cannot be provided. For this reason, the fuel that can exchange the fuel assembly 37 in the reactor, handle the fuel assembly 37 inside and outside the reactor, and transfer it to the fuel receiving and unloading facility in the opening from which the reactor stop rod drive mechanism 27 is removed. An entry / exit machine 101 is provided.

  The fuel access device 101 travels on the rail 111 on the ceiling 211 of the reactor building 210. A hoisting mechanism 103 for raising and lowering the gripper 102 that handles the fuel assembly 37 and for holding and releasing the fuel assembly 37 is installed on the upper part of the fuel loading / unloading machine 101. The winding mechanism 103 and the gripper 102 are connected by two pairs (four) of flexible members 104. Examples of the flexible member 104 include a tape and a chain made of a corrosion resistant material such as stainless steel.

  The base 105 of the winding mechanism has a structure that can move in two horizontal directions of XY. This is because if the fuel inlet / outlet machine 101 that covers the entire core 2 is used, the hole diameter of the door valve 107 is larger than the diameter of the core 2 or more. The core movement is performed using the XY movement of the base 105 of the hoisting mechanism 103.

  A support mechanism (support cradle) 106 for temporarily storing the new fuel assembly 37 and the like is installed in the main body of the fuel loading / unloading machine 101 in order to shorten the time when the fuel assembly 37 is replaced. As a result, after the spent fuel assembly 37 is taken out, the spent fuel assembly 37 and the new fuel assembly 37 are exchanged in the fuel inlet / outlet machine 101 without returning to the fuel handling system pit floor facility. Load into the furnace. The XY movement is also used for the eccentric operation of the gripper 102 at this time. A floor door valve 109 for sealing is attached to the lower part of the main body of the fuel input / output machine 101.

In order to shut off the reactor opening when the fuel assembly 37 is replaced with the outside air, a floor door valve 109 is provided in the sealed cylinder 110 and the reactor pit plug 108 so as to cover the opening from which the reactor stop rod drive mechanism 27 is removed. It is installed. By rotating the reactor pit plug 108, the floor door valve 109 can be installed in a predetermined direction, and by using the double track rail 111, the fuel assemblies 37 of the entire core 2 can be handled.

As described above, according to the fourth embodiment of the present invention, by using the opening from which the furnace stop rod drive mechanism 27 is removed, only one fuel input / output device 101 is required without the need for a fuel changer. Easy handling of the fuel assembly 37 is possible, which can contribute to a reduction in the amount of materials and can be adapted to a compact nuclear reactor structure.

1 is a longitudinal sectional view of a fast reactor according to a first embodiment of the present invention. FIG. 2 is a configuration diagram of a reactivity control assembly having the furnace stop rod of FIG. 1, and a side view showing a part of the reactivity control assembly along AA of FIG. 2B is a cross-sectional view of a reactivity control assembly having the furnace stop rod of FIG. 2A. FIG. FIG. 2 is an enlarged vertical sectional view of the furnace stop rod drive mechanism of FIG. 1. It is a figure for demonstrating operation | movement of the reactor stop rod grip part of the fast reactor of FIG. 1, Comprising: It is a figure which shows the state couple | bonded. It is a figure for demonstrating the operation | movement of the furnace stop rod holding | grip part of FIG. 4A, Comprising: It is a figure which shows the state isolate | separated. It is a block diagram of the reactor stop rod delatching mechanism of the fast reactor of FIG. It is a block diagram of the reactor stop rod delatching mechanism of the fast reactor which concerns on the 2nd Embodiment of this invention. It is a lower enlarged longitudinal cross-sectional view of the reactor stop rod drive mechanism of the fast reactor which concerns on the 3rd Embodiment of this invention. It is a fragmentary longitudinal cross-sectional view of the fuel access facility of the fast reactor which concerns on the 4th Embodiment of this invention. It is a top view of the fuel in / out state of the fast reactor of FIG. It is a longitudinal cross-sectional view of the conventional fast reactor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fast reactor, 2 ... Core, 3 ... Core tank, 4 ... Reflector, 5 ... Primary coolant, 6 ... Partition, 7 ... Reactor vessel, 8 ... Neutron shield, 9 ... Guard vessel, 10 ... Upper part Plug 11, drive shaft 12, reflector drive device 13 core support plate 14 electromagnetic pump 15 intermediate heat exchanger 18 inlet nozzle 19 outlet nozzle 24 rib 25 base 26 ... Reactivity control assembly, 27 ... Reactor stop rod drive mechanism, 28 ... Storage dome, 29 ... Upper support plate, 30 ... Partition plate, 31 ... Base, 37 ... Fuel assembly, 38 ... Entrance module, 39 ... Core support 51, reactor stop rod, 52 ... neutron absorber, 53 ... protective tube, 54 ... handling rod, 55 ... reactor stop rod handling head, 56 ... gripper, 57 ... dashram, 58 ... lower guide tube, 60 ... neutron Absorber Han Ring head, 61 ... motor, 62 ... twin ball screw, 63 ... ball nut, 64 ... extension pipe latch mechanism, 65 ... cyclo reducer, 66 ... upper guide pipe, 67 ... outer extension pipe, 68 ... inner extension pipe, 69 ... Reactivity control assembly handling head, 70 ... retaining magnet, 71 ... latch finger, 72 ... armature, 73 ... backup delatching drive motor, 74 ... rod, 75 ... permanent magnet, 76 ... coil, 77 ... bellows, 78 ... latch Bellows, 79 ... backup seal, 80 ... neutron absorber inner extension shaft, 81 ... neutron absorber outer extension shaft, 82 ... drive shaft latch mechanism, 83 ... cover gas seal portion, 84 ... drive shaft support stopper, 85 ... drive Outer housing, 86 ... Power cylinder, 87 ... Protection cylinder, 88 ... Rectifying plate, 101 ... Fuel in / out , 102 ... Gripper, 103 ... Hoisting mechanism, 104 ... Flexible member, 105 ... Base, 106 ... Support mechanism, 107 ... Door valve, 108 ... Reactor pit plug, 109 ... Floor door valve, 110 ... Sealed cylinder, 111 ... Rail: 200 ... Trumpet tube, 201 ... Handling rod, 202 ... Eye bolt, 203 ... Joint, 204 ... Guide tube handling head, 205 ... Latch link, 206 ... CRD (control rod drive mechanism) guide tube, 210 ... Reactor building, 211 ... Ceiling, 215 ... Inside extension pipe latch link, 220 ... Lattice plate

Claims (7)

A plurality of fuel assemblies constituting the core;
A reactivity control assembly containing a plurality of neutron absorbers for suppressing an initial excess reactivity disposed in the periphery of a reactor stop rod of a post-furnace shutdown system in a hexagonal tubular trumpet tube at the center of the core;
A core tank surrounding the outer periphery of the core;
A reflector that surrounds the outer periphery of the core and moves up and down;
A partition wall that surrounds the outer periphery of the reflector and forms the inner wall of the coolant flow path of the primary coolant;
An upper support plate for supporting the core tank and the partition;
An intermediate heat exchanger installed in the annular space above the upper support plate;
An electromagnetic pump disposed at the bottom of the intermediate heat exchanger;
A reactor vessel containing the fuel assembly, reactivity control assembly, reflector, partition, intermediate heat exchanger and electromagnetic pump and having an upper opening;
An upper plug for closing the upper opening of the reactor vessel;
A drive part and an upper guide pipe are provided, and an outer extension pipe and an inner extension pipe that are double pipes are arranged inside the upper guide pipe, and are provided at the lowermost end of the outer extension pipe to control the reactivity of the core. It has a gripper part that detachably holds the furnace stop rod that is pulled out or inserted by excitation of the holding magnet, and the inner extension pipe is dropped by de-exciting the holding magnet during scram so that the gripper part A furnace stop rod drive mechanism for separating the furnace stop rod;
It is disposed around the reactor stop rod drive mechanism, has a double tube drive shaft of an outer extension shaft and an inner extension shaft, and grips the handling head above the neutron absorber at the lower end of the inner extension shaft. A gripper portion is provided, and when the neutron absorber is gripped, the inner extension shaft is pulled up and the outer extension shaft and the inner extension shaft are inserted into the neutron absorber handling head to reach the neutron absorber handling head. A plurality of neutron absorber driving mechanisms that can individually move each neutron absorber up and down by pushing down the outer extension shaft later and gripping it with a latch finger of the gripper part to couple with the neutron absorber;
Have
A fast reactor, wherein the reactor stop rod drive mechanism and the neutron absorber drive mechanism are integrated and arranged in the center of the upper plug. The furnace stop rod is cylindrical, and a head is formed on the top of the furnace stop rod,
The reactivity control assembly is disposed in the wrapper tube so as to surround the furnace stop rod, and is divided into a plurality of portions in the circumferential direction between the guide tube and the wrapper tube. A plurality of fan-shaped neutron absorbers,
A cylindrical neutron absorber handling rod that protrudes upward from the top of the reactivity control assembly when the neutron absorber is moved to the lowest position is disposed, and a neutron absorber handling is disposed on the top of the neutron absorber handling rod. The head is formed,
The fast reactor according to claim 1. The furnace stop rod drive mechanism is
A latch ring that opens when the holding magnet is de-energized and separates the inner extension tube;
A rod that vertically penetrates the holding magnet;
An armature disposed in contact with the holding magnet and below the holding magnet;
A backup delatching drive motor that forcibly separates the armature from the holding magnet by depressing the rod and depressing the armature with the rod;
The fast reactor according to claim 1, comprising: The neutron absorber drive mechanism is installed at equal intervals around the furnace stop rod drive mechanism,
Each drive shaft of the neutron absorber drive mechanism is provided with a drive shaft support stopper at the upper end,
In addition to the cover gas seal portion on the upper surface of the upper plug, the entire drive unit outer housing is configured in a seal structure,
The fast reactor according to claim 1. The furnace stop rod drive mechanism includes an extension pipe latch mechanism that lifts the upper part of the outer extension pipe,
A power cylinder installed in the extension pipe latch mechanism to push up only the outer extension pipe;
Have
When the outer extension pipe is pushed up by the power cylinder, the latch finger holding the furnace stop rod handling head is closed, and the furnace stop rod falls by its own weight. The fast reactor according to claim 1. A fuel inlet / outlet machine inserted into the opening of the upper plug from which the furnace stop rod drive mechanism has been removed;
The fuel access machine is
A hoisting mechanism supported by a base disposed above the opening of the upper plug and movable in two horizontal directions perpendicular to each other;
A support mechanism for temporarily storing the fuel assembly suspended by the winding mechanism;
The fast reactor according to claim 1, wherein: At least two routes of fuel entry / exit rails disposed on the ceiling of the reactor building containing the reactor vessel and supporting the fuel entry / exit machine in a horizontal direction;
A reactor pit plug disposed above the upper plug at a ceiling height of the reactor building;
A floor door valve that can rotate and open about a vertical axis relative to the reactor pit plug;
Have
The fast reactor according to claim 6, wherein the hoisting mechanism is configured to be movable over the opening of the floor door valve and directly above all of the plurality of fuel assemblies in the core. .

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