JP2006084178A - Refueling machine of nuclear installation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain a smooth movement of core structure without swing of core structure (fuel assemblies 10) and grapple 8 caused by crossflow generated in water in a refueling machine of a nuclear installation represented by a nuclear power station. <P>SOLUTION: An extension type cylindrical shield 9 which follows the movement of an elevator mechanism 3 is placed to the refueling machine so as to surround the elevation mechanism 3 of the refueling machine. By attaching the shield 9, the effects of crossflow generated in water on the fuel assemblies 10 and the grapple 8 as a representative core structure are extremely eliminated and the fuel assemblies 10 and the grapple 8 are not swung and so the smooth movement of a core structure becomes possible. As a smooth movement of core structure becomes possible, time necessary for the movement of the core structure is shortened and as a result, the outage period of a reactor due to regular inspection is shortened. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel exchanger for a nuclear facility, and relates to a technique for handling articles such as a fuel assembly and a control rod for a nuclear reactor suspended and supported by the fuel exchanger so as not to be shaken as much as possible in water.

  A nuclear facility refueling machine includes a traveling vehicle that travels along a pool in which fuel assemblies are stored, a traversing cart that travels on the traveling cart in a horizontal direction perpendicular to the traveling cart, and its traversal. A telescopic structure telescopic mechanism supported by a carriage and telescopically movable, a gripping mechanism that is disposed under the telescopic mechanism to grip and release the fuel assembly, and the gripping mechanism and the telescopic mechanism simultaneously. A winch that is driven up and down to expand and contract the expansion and contraction mechanism, and a fuel insertion guide that is provided at the bottom of the expansion and contraction mechanism and covers the outside of the fuel assembly that is gripped and suspended by the gripping mechanism. Have.

  This fuel insertion guide suppresses the shaking of the fuel assembly caused by free vibration of the fuel assembly and the lifting mechanism in the pool water, and is inserted between the fuel storage spaces in which other fuel assemblies that are not to be moved are stored. It has a function of securing a storage space for the fuel assembly to be guided and guiding the fuel assembly to the fuel insertion space.

  In addition, in order to achieve the function of securing the storage space for the fuel assembly to be inserted into the fuel storage space, assuming that the outer shape of the fuel assembly is a square shape with a side of about 150 mm, the fuel insertion guide is an internal method. Each side becomes a square of about 200 mm (for example, see Patent Document 1).

JP 2003-107188 A

  The gripping device of a fuel exchanger at a nuclear reactor facility is also called a grapple, and there is an elevating mechanism and itself for items such as fuel assemblies, control rods, and double blade guides for reactors that are gripped and suspended by the gripping device. In addition to the shaking generated by the free vibration of the head, the lifting mechanism, the gripping device, and the fuel assembly may be shaken not only by their own movement but also by an external force generated by a lateral water flow generated in the water.

  The fuel changer equipped with the fuel insertion guide described above suppresses the rolling generated in the fuel assembly due to free vibration by contact with the fuel insertion guide, so that the space between the fuel insertion guide and the fuel assembly is reduced. There must be. In addition, when inserting a fuel assembly into a fuel storage space in which another fuel assembly is already stored, the fuel assembly that has already been stored is pressed down so that the storage space for the fuel assembly to be inserted is reduced. Since the fuel insertion guide has a function of ensuring, the outer periphery of the fuel insertion guide is determined by the space for inserting one fuel assembly, and the size of the fuel fuel insertion guide can be freely determined. I can't. That is, in the above-described known example, the space between the fuel assembly and the fuel insertion guide is limited, and thus there is a possibility that the fuel insertion guide may be shaken by the lateral flow generated in the water.

  Therefore, according to the present invention, because of the shaking caused by the lateral flow generated in the water, the insertion of an article such as a fuel assembly for a nuclear reactor or a control rod into the target area and the lifting of the article targeted are prevented. It was made with the aim of making it possible to work smoothly.

  The basic requirements of the present invention are a traveling cart, a traversing cart that is movably installed on the traveling cart, a gripping device that is installed to be movable up and down on the traversing cart, and a telescopic cart installed on the traversing cart. A fuel exchanger for a nuclear facility comprising: a lifting mechanism that restrains a horizontal direction of the gripping device; and a shield that is provided on the traverse carriage that surrounds the gripping device and the lifting mechanism, and that extends vertically. Enclose the object that is held and suspended by the gripping device of the exchange, the lifting mechanism and the gripping device with a shield so that the lifting mechanism, the grapple, and the article suspended by the grapple are not shaken by the horizontal water flow in the water. To do.

  In the fuel changer of the present invention, the lifting mechanism, the gripping device, and the articles suspended by the gripping device are prevented from being affected by the horizontal flow generated in the water as much as possible by the shield. Therefore, the article can be handled smoothly and the period of reactor shutdown due to periodic inspection can be minimized.

  A lift mechanism for the fuel exchanger in the nuclear reactor facility and a shield that can be stretched up and down to surround the horizontal circumference of the grapple and the fuel assembly and control rod suspended on the grapple are provided on the carriage of the fuel exchanger. Suppresses the effects of horizontal water currents occurring in water on articles, lifting mechanisms and grapples. As a result, the article can be handled without causing as much shaking as possible to the article such as the fuel assembly and the control rod in the furnace and the grapple suspended from the grapple of the refueling machine.

  The reactor pressure vessel 7 is stored in the reactor building 16 of the nuclear power plant. The reactor pressure vessel 7 is filled with reactor water so that the core is submerged. In the core, a nuclear fuel assembly 10 and control rods are placed as components of the core. In a nuclear power plant, the fuel assembly 10 for a nuclear reactor loaded in the core is periodically replaced. When the fuel assembly 10 is replaced, the upper cover of the reactor pressure vessel 7 is opened and communicated with the reactor well 5 vertically. The reactor well 5 is disposed on the reactor pressure vessel 7, and when the fuel assembly 10 is replaced, the reactor well 5 is filled with water, and the spent fuel pool 14 in the reactor building 16 is filled. And communicated through the canal 13.

  The canal 13 is a water channel that connects the reactor well 5 and the spent fuel pool 14. Normally, the water channel is closed by a weir, but the reactor is stopped and the fuel assembly in the reactor pressure vessel 7 is closed. When exchanging the fuel tank 10, the water channel is opened so that the fuel assembly 10 can be moved between the reactor well 5 and the spent fuel pool 14 in the submerged state by the fuel exchanger. Such a canal 13 is secured with a water depth at which the moving fuel assembly 10 can be submerged and a width in which a shield 9 described later can move horizontally.

  The refueling machine housed in the reactor building 16 of the nuclear power plant suspends the fuel assembly 10 for the nuclear reactor, the control rod, the double blade guide, etc., by holding it with a gripping device called a grapple 8. It is used to move while. Such movement is employed when the fuel assembly 10 in the core is replaced or the loading position of the fuel assembly 10 in the core is changed.

  A water spray pipe is provided in the reactor well 5, and the water spray pipe 4 passes through the reactor outlet coolant outlet nozzle 6 from the reactor pressure vessel 7 in order to take decay heat generated from the fuel during the reactor shutdown. It is used when water is sucked in, passed through a heat exchanger, and then returned to the reactor well 5 again. A water flow in the horizontal direction is generated in the reactor pressure vessel 7 and in the reactor well 5 by the water absorption by the coolant outlet nozzle 6 and the discharge of the water from the water spray pipe 4 when the reactor is stopped. Due to this lateral flow, there is a possibility that an article such as the fuel assembly 10 or the grapple 8 gripped by the grapple 8 by the fuel exchanger may be shaken.

In order to reduce the possibility of the shaking, the refueling machine is configured as follows. That is, the refueling machine includes a traveling vehicle that travels in the direction in which the reactor well 5 and the spent fuel pool 14 are arranged across the reactor well 5, and a horizontal direction that is orthogonal to the traveling direction of the traveling vehicle on the traveling vehicle. A traverse trolley that travels to the telescope, a telescopic structure lifting mechanism 3 that is supported by the traverse trolley, and that can extend and contract in the vertical direction, and is disposed below the telescopic structure of the lift mechanism 3 to grip or separate the fuel assembly 10. The grapple 8 to be moved, the first winch 17 for expanding and contracting the telescopic structure of the lifting mechanism 3 by simultaneously driving the grapple 8 and the lifting mechanism 3 in the vertical direction, and the lifting mechanism 3 and the grapple 8 to the transverse carriage 2 in the horizontal direction. A shield 9 having a three-stage telescopic structure and a telescopic structure of the shield 9, which is provided so as to be surrounded by a cylindrical shape and expands and contracts in the vertical direction. And a second winch 18 for stretching the structure in the vertical direction.

  The first winch 17 is installed in the traversing carriage 2, and the wire 19 wound around the drum 15 of the first winch 17 is connected to the lowermost part of the telescopic structure of the lifting mechanism 3. The telescopic structure of the elevating mechanism 3 is a structure in which a cylindrical structure is combined in multiple upper and lower stages that move relatively in the vertical direction, and a structure in which the lower structure part is hooked up on the upper structure part, and A structure in which the upper structure portion can be hooked and supported so that the lower structure portion does not fall off is employed. Therefore, when the first winch 17 is driven and the drum 15 is rotated, the wire 19 is wound or fed around the drum 15 according to the rotation direction, and the lifting mechanism 3 extends downward or contracts upward. In other words, the expansion / contraction position can be changed in the vertical direction depending on the rotation amount of the drum 15.

  As shown in FIG. 5, a drum 30 having the same diameter as that of the drum 15 is connected to the drum 15 so that the drum 15 can rotate in the same direction at the same time as the drum 15. The wire 31 fed out from the drum 30 is connected to the grapple 8. Therefore, when the first winch 17 rotationally drives the drum 15, the drum 30 also rotates and the lowermost end portion of the elevating mechanism 3 and the grapple 8 can simultaneously move up and down in the same direction by the same amount. The grapple 8 is constrained by the lower end portion of the elevating mechanism 3 that the upper portion is inserted into the lower end portion of the elevating mechanism 3 and shakes greatly to the left and right, so that the grapple 8 can be easily positioned. The lower end of the elevating mechanism 3 and the grapple 8 are not shown in the figure, but when the grapple 8 loses its support by the wire and falls, the grapple 8 is received and the grapple 8 is supported by the elevating mechanism 3. Has a relational structure.

  The second winch 18 is installed in the traversing carriage 2, and the wire 12 wound around the drum 11 of the second winch 18 is connected to the lowermost cylindrical structure 9 c of the cylindrical telescopic structure of the shield 9. Has been. The upper cylindrical structure 9a of the shield 9 has a size that includes the middle cylindrical structure 9b, and the middle cylindrical structure 9b has a size that includes the lower cylindrical structure 9c. The upper cylindrical structure 9 a is provided with its upper end fixed to the traversing carriage 2. A ring-shaped guide 20 is fixed to the lower inner side of the upper cylindrical structure 9a in two upper and lower stages. The upper and lower two-stage guide 20 surrounds the middle cylindrical structure 9b on the inside so as to freely slide in the vertical direction. A ring-shaped stopper 22 is fixed to the upper end of the middle cylindrical structure 9b so as to be hooked on the upper stage in the upper and lower two-stage guides 20. The stopper 22 is finished to an outer diameter that can move up and down inside the upper cylindrical structure 9a.

  Similarly, a ring-shaped guide 21 is fixed to the lower inner side of the middle cylindrical structure 9b of the shield 9 in two upper and lower stages. The upper and lower two-stage guide 21 surrounds the lower cylindrical structure 9c on the inside so as to freely slide in the vertical direction. A ring-like stopper 23 is fixed to the upper end of the lower cylindrical structure 9c so as to be hooked on the upper stage of the upper and lower guides 21 fixed to the middle cylindrical structure 9b. The stopper 23 has an outer diameter that can move up and down inside the middle cylindrical structure 9b.

  A ring-shaped support member 24 is fixed to the lower end of the lower cylindrical structure 9c of the shield 9 so as to protrude to a position where the lower end of the middle cylindrical structure 9b can be hooked. The wire 12 of the second winch 18 is fixed to the upper end of the lower cylindrical structure 9c.

  In such a structure of the shield 9, when the second winch 18 is driven to rotate the drum 11, the shield 9 extends downward or contracts upward depending on the rotation direction. Depending on the amount of rotation, the expansion / contraction position can be changed in the vertical direction. When the wire 12 is fed out from the drum 11 by the second winch 18, the lower cylindrical structure 9c descends. At that time, since the support member 24 supports the middle cylindrical structure 9b, the middle cylindrical structure 9b also descends while sliding on the guide 20. When the middle cylindrical structure 9b is lowered, the stopper 22 is also lowered, so that the stopper 22 is finally received by the guide 20 so that the middle cylindrical structure 9b stops descending, and the lower cylindrical structure 9b. Only the object 9c continues to descend while sliding on the guide 21. As the lower cylindrical structure 9c continues to descend, the stopper 23 is finally received by the guide 21 and the lower cylindrical structure 9c stops descending.

  The upper and lower two-stage guides 20 provided on the upper cylindrical structure 9a are separated from each other up and down to contact the middle cylindrical upper structure 9b and guide the lowering of the middle cylindrical upper structure 9b. When the structure 9b descends, it can be prevented from shaking in the horizontal direction as much as possible. Further, even in a state where the expansion / contraction operation of the shield 9 is stationary, it is possible to prevent the horizontal movement as much as possible. This is also true between the middle cylindrical structure 9b and the lower cylindrical structure 9c.

  When the second winch 18 is driven and the wire 12 is wound around the drum 11 while the shield 9 is extended, the shield 9 can be contracted upward. That is, when the wire 12 is wound around the drum 11 by the second winch 18, the lower cylindrical structure 9c rises while sliding on the guide 21, and rises simultaneously with the lower cylindrical structure 9c. The support member 24 comes into contact with the lower end of the middle cylindrical structure 9b, and finally the support member 24 hooks the lower end of the middle cylindrical structure 9b so that the middle cylindrical structure 9b becomes the lower cylindrical structure 9c. Raise at the same time. The upper cylindrical structure 9b is raised while sliding on the guide 20 fixed to the upper cylindrical structure 9a. When the cylindrical structures 9b and 9c continue to rise, finally, the lower cylindrical structure 9c is located inside the middle cylindrical structure 9b, and the middle cylindrical structure 9b is the upper cylindrical structure. The shield 9 is housed inside the object 9a and is in the most contracted state.

  Since the guide is slidably guided at the two upper and lower two positions with one cylindrical structure in such a contraction operation of the shield 9, horizontal shaking is suppressed. Even if the shrinkage of the shield 9 is stopped while the shield 9 is being shrunk, the horizontal swing of each cylindrical structure constituting the shield 9 is similarly suppressed at the stopped position.

  The first and second winches 17 and 18 are provided with a brake device for stopping the rotation of the drums 11 and 15 on the drums 11 and 15 as a stopping device for stopping the telescopic structure of the shield 9 and the lifting mechanism 3. Yes. The brake device exhibits the function of stopping and allowing the rotation of the drums 11 and 15, and when the function is performed to stop the rotation of the drums 11 and 15, the telescopic structure of the shield 9 and the lifting mechanism 3 is expanded and contracted. When the operation is stopped and the expansion / contraction position can be maintained and the drums 11 and 15 are allowed to rotate, the telescopic structure of the shield 9 and the elevating mechanism 3 causes the rotation of the drums 11 and 15. Can be achieved.

  The traversing cart 2 includes a control device 25 that controls the first and second winches 18 so that the shield 9 automatically expands and contracts in accordance with the extending and retracting operation of the lifting mechanism 3. The control device 25 controls the number of rotations of the drum 11 of the second winch 18 that controls expansion and contraction of the shield 9 and the drum 15 of the first winch 17 that controls expansion and contraction of the lifting mechanism 3 to control the expansion and contraction operation of the shield 9. 3 is automatically interlocked with the expansion and contraction movements to follow. Specifically, the control device 25 grasps the lower end position of the elevating mechanism 3 from the rotational speed of the drum 15 of the first winch 17 that controls expansion and contraction of the elevating mechanism 3, and grapple 8 and the fuel assembly suspended from the grapple 8. The lower end of the shield 9 is positioned below the lower end of the fuel assembly 10 suspended from the grapple 8 or the lower end of the fuel assembly 10 so that the influence of the lateral flow is not exerted on the body 10 as much as possible. The expansion / contraction operation of the shield 9 is interlocked with the expansion / contraction operation of the elevating mechanism 3 by controlling the rotation speed of the drum 11 of the second winch 18 that controls expansion / contraction of the shield 9 so that the lower end of the shield 9 is in the same position. Linked operation is performed.

  In the control device 25, the above-described interlocking operation of the first and second winches 17 and 18 is stopped, and the first and second winches 17 and 18 are independently operated so as to operate independently. Equipped with a switching device for operation mode with linked operation. When the independent operation mode is selected by the switching device, the interlocking operation of the winches 17 and 18 by the control device 25 is prevented, and the expansion / contraction operation of the elevating mechanism 3 and the shield 9 can be individually controlled by the operation of the winches 17 and 18.

  The use of such a fuel changer in a nuclear power plant will be described below. That is, the fuel changer is used when the fuel assembly 10 is moved during fuel replacement work or when the fuel assembly 10 is pulled out or inserted from the core. During the refueling operation, the reactor is stopped, the top cover of the reactor pressure vessel 7 is removed, and water is filled in the reactor well 5. The weir between the canal 13 and the reactor well 5 is removed, and the reactor well 5 and the spent fuel pool 14 are communicated with each other by the canal 13. Further, the in-core structure is removed from the reactor pressure vessel 7 so that the core can be seen from above so that the fuel exchanger can access the core.

  Thereafter, the grapple 8 is positioned directly above the fuel assembly 10 for replacement in the core by traveling the traveling carriage 1 and the traveling carriage 2. Under this circumstance, in order to take the decay heat generated from the reactor core while the reactor is shut down, as shown in FIG. 2, water is sucked from the reactor pressure vessel 7 through the reactor outlet coolant outlet nozzle 6 to exchange heat. After cooling through the vessel, the water is again discharged from the sprinkler pipe 4 to the reactor well 5. Therefore, a flow is generated in the water in the reactor well 5 and the reactor pressure vessel 7, and the flow includes a component of a horizontal flow.

  The first winch 17 and the second winch 18 are operated as follows so that the elevating mechanism 3 and the grapple 8 are not shaken in response to the horizontal flow. That is, as shown in FIG. 1A, the shield 9 and the lifting mechanism 3 are initially contracted most. In such a state, the shield 9, the lifting mechanism 3, and the grapple 8 are located above the water surface of the pool of the reactor well 5. From this state, the first winch 17 is operated and the wire 19 is fed out from the drum 15 of the first winch 17 so that the lifting mechanism 3 extends downward, and the grapple 8 also descends simultaneously. At the same time, the shield 9 extends downward by operating the second winch 18 and feeding the wire 12 from the drum 11 of the second winch 18. Also in the extension process, the first and second winches 17 and 18 are arranged so that the shield 9 can surround the horizontal periphery of the elevating mechanism 3 and the grapple 8 as shown in FIG. The rotational speeds of the drums 11 and 15 are individually adjusted to adjust the extension amounts of the shield 9 and the lifting mechanism 3 so that the lower end of the shield 9 is always lower than the lower end of the grapple 8. By doing so, a water flow (hereinafter referred to as a horizontal water flow) containing a component of a horizontal flow generated by the flow of water discharged from the water spray pipe 4 hits the shield 9 to the grapple 8 and the lifting mechanism 3. Not reach. Therefore, the grapple 8 and the lifting mechanism 3 do not shake.

  In this way, the grapple 8 and the lifting mechanism 3 can be lowered directly above the fuel assembly 10 for replacement without shaking. Thereafter, as shown in FIG. 1C, the grapple 8 holds the fuel assembly 10. When gripping the fuel assembly 10, the grapple 8 can be quickly and reliably gripped without waiting for the grapple 8 or the elevating mechanism 3 to swing until the swing is settled. After the grapple 8 grips the fuel assembly 10, the lifting mechanism 3 is contracted by operating the first winch 17 and winding the wire 19 around the drum 15. As a result, the fuel assembly 10 held by the grapple 8 is housed inside the shield 9 as shown in FIG. The surroundings are surrounded. When the extension position of the shield 9 is excessively low, the second winch 18 is operated, the wire 12 is wound around the drum 11, the shield 9 is contracted, and the fuel as shown in FIG. The minimum extension length is set so that the horizontal water stream does not directly hit the assembly 10. The brake of the second winch 18 is operated so that the extension length can be maintained, and the rotation stop state of the drum 11 is maintained.

  After that, the traveling cart and the traversing cart 2 are run to move the fuel assembly 10 to the entrance of the canal 13. Even during this movement, the shield 9 receives the resistance of the water that the fuel assembly 10 is to receive due to the movement so that the fuel assembly 10 is not affected by the movement as much as possible, and is held by the grapple 8. 10 is kept as vertical as possible. Next, in order to pass the fuel assembly 10 through the canal 13, the second winch 18 is operated to reduce the shield 9 to the most contracted state as shown in FIG. The fuel assembly 10 is passed through the canal 13 in a state where the fuel assembly 10 is submerged below the water surface, and the fuel assembly 10 is moved into the spent fuel pool 14.

  The fuel assembly 10 that has reached the spent fuel pool 14 is stored in a fuel storage rack that is deployed in the water in the spent fuel pool 14. In the case where the fuel assembly 10 is not desired to be tilted or shaken due to water flow or water resistance, the fuel assembly 10 that is held by the grapple 8 by extending the shield 9 also in the spent fuel pool 14. And surrounding the horizontal direction of the lifting mechanism 3. By doing in this way, the phenomenon that the fuel assembly 10 gripped by the water flow in the spent fuel pool 14 or the resistance of the moving water can be prevented, and the fuel assembly 10 is maintained in a vertical posture. When the fuel assembly 10 reaches directly above the fuel storage rack, the elevating mechanism 3 is extended to lower the fuel assembly 10 into the fuel storage rack. Thereafter, the grapple 8 is removed from the fuel assembly 10 and the lifting mechanism 3 and the shield 9 are contracted to the uppermost position. In this way, the fuel assembly 10 can be quickly and reliably stored in the fuel storage rack.

  When the new fuel assembly 10 is loaded onto the core, the new fuel assembly 10 is gripped by the grapple 8 and the gripped new fuel assembly 10 is surrounded by the shield 9 until the new fuel assembly 10 is loaded immediately above the core. The new fuel assembly 10 is moved by the traveling action of the traveling cart 1 and the traversing cart 2, and then the elevating mechanism 3 is further extended to load the new fuel assembly 10 into the core. Thereafter, the grapple 8 is removed from the new fuel assembly 10, and the elevating mechanism 3 and the shield 9 are retracted to the uppermost position.

  When the new fuel assembly 10 is lowered toward the core, the control device 25 is switched to the linked operation mode by the switching device. If it does in that way, the control apparatus 25 will control to the interlocking operation state of the 2nd winch 18 which manages expansion / contraction of the shield 9, and the 1st winch 17 which controls expansion / contraction of the raising / lowering mechanism 3. That is, the control device grasps the lower end position of the elevating mechanism 3 from the rotational speed of the drum 15 of the first winch 17 that controls expansion and contraction of the elevating mechanism 3, and grapple 8 and the new fuel assembly suspended by the grapple 8. 10 so that the lower end of the shield 9 descends before the lower end of the grapple 8 and the suspended new fuel assembly 10 so that the influence of the horizontal water flow does not reach as much as possible. The number of rotations of the drum 11 of the second winch 18 is controlled.

When the fuel assembly 10 is gripped by the grapple 8 from the core and the fuel assembly 10 is pulled up from the core into the shield 9 and then the control device is switched to the interlock operation mode, the fuel assembly 10 is removed from the core to the fuel storage pool. The number of rotations of the drum 11 of the second winch 18 that controls expansion and contraction of the shield 9 and the drum 15 of the first winch 17 that controls expansion and contraction of the elevating mechanism 3 are controlled in the ascending process of the fuel assembly 10 that occurs in the process of moving to The device will be in control. That is, the control device grasps the lower end position of the elevating mechanism 3 from the rotational speed of the drum 15 of the first winch 17 that controls expansion and contraction of the elevating mechanism 3, and grapple 8 and the new fuel assembly suspended by the grapple 8. 10, the expansion and contraction of the shield 9 is prevented so that the lower end of the shield 9 does not rise ahead of the lower end of the grapple 8 and the suspended new fuel assembly 10 so that the influence of the horizontal water flow does not reach as much as possible. The drum rotation speed 11 of the second winch 18 is controlled. By such control, the fuel exchange operation is easily and reliably performed. As a result, the reactor shutdown period due to periodic inspections is shortened.

  When reloading the fuel assembly 10 in the core to another position in the same core, the lower ends of the elevating mechanism 3, the grapple 8 and the shield 9 are extended to just above the core to maintain the state. In this case, the control device is switched to the independent operation mode. Next, the fuel assembly 10 is gripped by the grapple 8 from the core. The fuel assembly 10 held by the grapple 8 is pulled up by contracting the lifting mechanism 3. When the lower end of the fuel assembly 10 is pulled up above the core, the fuel assembly 10 is surrounded by the shield 9 in the horizontal direction. In such a state, the traveling carriage 1 and the traversing carriage 2 are made to travel and are positioned immediately above the other positions where the fuel assemblies 10 gripped by the grapple 8 are reloaded. Thereafter, the elevating mechanism 3 is extended to lower the fuel assembly 10 into the core, and the fuel assembly 10 is removed from the grapple 8. When the fuel assembly 10 is reloaded in this way, the lower end of the shield 9 is maintained directly above the core until the fuel assembly 10 is pulled up from the core and lowered into the core. Therefore, the fuel assembly 10 is not tilted or shaken by a water flow or water resistance, and the loading position of the fuel assembly 10 can be quickly and reliably changed.

  When it is desired to maintain the position of the lower end of the shield 9 at a midway position that does not extend, the brake for the drum 11 of the second winch 18 is activated when the lower end of the shield 9 reaches the midway position. This is done by stopping 11 rotations.

  In addition, the above example is an example in which the fuel assembly 10 is handled as an article, but the same applies to the case where a control rod of the core (also referred to as a control rod assembly) is handled as an article.

  The fuel exchanger according to the present invention is used for handling a fuel assembly for a nuclear power plant nuclear reactor in water.

It is a principal part figure of the fuel exchanger which showed the handling procedure of the fuel assembly for reactors at the time of the fuel replacement | exchange by the fuel exchanger of this invention from the (a) figure to the (e) figure in the cross section. It is a longitudinal cross-sectional view of the reactor well vicinity of the reactor building in which the fuel exchanger of this invention was installed. FIG. 1 is a main part view of a fuel exchanger showing a state in which the fuel exchanger of the present invention is ready to pass through a canal by grasping a fuel assembly, and the right figure is a front view as seen from the front of the canal entrance and exit, The figure is a sectional view seen from the side of the front view. It is principal part sectional drawing of the shield 9 of the fuel exchanger by this invention. It is a longitudinal cross-sectional view of the raising / lowering mechanism part which showed the suspension support relationship of the raising / lowering mechanism and holding | grip apparatus of the fuel exchanger by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Traveling trolley, 2 ... Traversing trolley, 3 ... Elevating mechanism, 4 ... Sprinkling pipe, 5 ... Reactor well, 6 ... Reactor stop nozzle at the time of reactor stop, 7 ... Reactor pressure vessel, 8 ... Grapple, 9 ... shield,
DESCRIPTION OF SYMBOLS 10 ... Fuel assembly, 11 ... Second winch drum, 12, 19, 31 ... Wire, 13 ... Canal, 14 ... Spent fuel pool, 15 ... First winch drum, 16 ... Reactor building, 17 ... 1st winch, 18 ... 2nd winch, 20, 21 ... guide, 22, 23 ... stopper, 24 ... support member, 25 ... control device.

Claims (4)

Traveling cart,
A traversing carriage movably installed on the traveling carriage;
A gripping device installed on the traversing carriage so as to be movable up and down;
An elevating mechanism that is telescopically installed on the traversing cart and restrains the horizontal direction of the gripping device;
A shield that is provided on the traversing carriage that surrounds the gripping device and the lifting mechanism;
Refueling machine for nuclear facilities equipped with. In claim 1,
The shield has a telescopic structure that expands and contracts in the vertical direction,
A drive mechanism for expanding and contracting the telescopic structure shield in the vertical direction;
Refueling machine for nuclear facilities equipped with. In claim 2,
The drive mechanism is a nuclear power facility refueling machine including a stop device that stops expansion and contraction of the shield. In claim 3,
A first winch connected to the lifting mechanism and extending and retracting the lifting mechanism;
A second winch connected to the shield and extending or retracting the shield;
Control means for controlling the drive amount of the second winch so that the lower end of the shield is positioned below the gripping device based on the drive amount of the first winch;
Refueling machine for nuclear facilities equipped with.

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