KR100289790B1 - Integrated upper structure assembly of a nuclear reactor being capable of preventing strds from spattering - Google Patents

Abstract

PURPOSE: An upper structure of compact nuclear reactor is provided to allow maintenance work and reactor head lifting work to be easily performed, while improving safety by preventing scattering of studs for coupling reactor head. CONSTITUTION: An upper structure comprises a plurality of control rod driving devices(3), a reactor head lifting device(4), and a cooling device(2) for cooling control rod coils(32). The cooling device includes a cylinder(21) having a lower end coupled to a ring type support(14) of a reactor head(11); guide pipes(24) installed onto a support board(23) arranged onto the cylinder, and which wraps the control rod coils of the rod driving devices, and forms a cooling air passage communicated to the cylinder; a cooling branch pipe(25) arranged along the upper circumference of the cylinder; cooling ducts(27) installed onto the cooling branch pipe; and cooling pipes(28) connected to the cooling ducts. The reactor head lifting device includes lifting columns(41) which are installed in a vertical direction along the three directions of outer periphery of the cylinder, and have lower ends coupled to the reactor head.

Description

INTEGRATED UPPER STRUCTURE ASSEMBLY OF A NUCLEAR REACTOR BEING CAPABLE OF PREVENTING STRDS FROM SPATTERING}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dense reactor superstructure having a fly-by-product protection function, and in particular, components such as a reactor head lifting device and a control rod coil cooling device constituting the reactor superstructure in a so-called Korean pressurized water reactor. It can be easily maintained and handled, and the reloading period of the fuel rod can be shortened by making it easy to lift the reactor head, and the studs that fix the reactor head to the reactor pressure vessel by the fly-by barrier can be scattered. The present invention relates to a compacted reactor superstructure having safety features and improved fly-by protection.

The reactor superstructure in the so-called Korean pressurized water reactor is composed of control rod drive devices, reactor head lifting device, control rod coil cooling device, and the like, which will be described with reference to FIG. 5.

The control rod drive 71 is installed in the reactor core to maintain and regulate the output of the reactor and to stop the reactor. The control rod assemblies including the substance absorbing neutrons in the reactor pressure vessel 6 are installed at the core of the reactor. It is installed above the reactor head 61 to draw in and draw out.

The control rod drive 71 is a reactor from control rod assemblies through a plurality of nozzles 63 protruding over the reactor head 61, the edges of which are detachably coupled by studs 62 to the reactor pressure vessel 6. The control rod assemblies are brought into or out of the core substantially by raising and lowering the extension shafts (not shown) extending longer above the head 61. In addition, the control rod drive device 71 is a control rod coil (73) installed around the motor housing (not shown) connected to the upper end of the nozzle (63) in order to elevate the extension shaft, and extends upwardly from the motor housing to the elevating the extension shaft It has an upper housing 72 to be wrapped.

Therefore, when the control rod coil 73 is energized, the extension shaft in the upper housing 72 is moved up and down by using the magnetic force generated at this time as a power source, so that the control rod assemblies are raised and lowered, thereby controlling the output of the reactor. When the control rod assembly ascends to the top of the core, the reactor generates a maximum output.

On the other hand, since the control rod coils 73 constituting the control rod drive device 71 always have current flowing during the operation of the reactor, the control rod coils 73 are air-cooled so that the control rod coils 73 are not overheated by the heat generated at this time. The temperature of the control rod coils 73 must be properly maintained. To this end, a control rod coil cooling apparatus 75 to be described below is provided.

Reactor head lifting device (8) has a lower outward flange (82) bolted to the pedestal (64) installed along the outer circumference of the reactor head (61) and formed with a plurality of cooling holes (83) around the lower half. Cylindrical 81 and three lifting columns 85 which are vertically pinned at equal intervals along the top of the cylinder 81 are installed vertically (shown here for the sake of convenience, the lifting columns are respectively installed on both sides of the cylinder). Have

When lifting the reactor head 61, the studs 62 fastened to the pressure vessel 6 are released to allow the reactor head 61 to be separated from the pressure vessel 6, and then on top of the lifting columns 85, The lifting frame (not shown) is coupled by a crane (not shown) installed inside the reactor containment vessel (not shown), and the lifting head is lifted by the crane by lifting the columns 85 and the cylinder 81. (61) can be lifted.

The control rod coil cooling device 75 is fastened to the cylinder 81 in a sealed assembly form around the lower half of the cylinder 81 so as to surround the cooling hole 83 of the cylinder 81, and the inner peripheral surface and the outer peripheral surface of the cylinder 81. A cooling cylinder 76 having a support bar 77 formed between the upper and lower ring 65 of the pressure vessel 61 and forming a cooling air chamber therebetween, and the cooling cylinder 76; Cooling duct 78 is installed along the upper edge of the cooling duct 78 to communicate with the cooling cylinder 76 and connected to an upper side of the cooling duct 78 and discharged by driving a built-in cooling fan (not shown). On the support plate 87 to surround the cooling pipe 79 for performing the operation, the control rod coil cooling guide tube support plate 87 for partitioning the inside of the cylinder 81 up and down, and the control rod coil 73 It is supported and passed through the inside of the cylinder 81 between the control rod coils 73 and the inner circumferential surfaces. The air passage has a cooling coil control rod guide tubes (89) to form a.

Accordingly, when the cooling fan installed in the cooling pipe 79 is driven, the cooling air passes through the cooling air passages between the cooling guide pipes 89 and the control rod coils 73 by the suction force of the cooling fan. 81, the coils 73 are cooled in the process of being introduced into the inside, and the cooling air introduced into the cylinder 81 is introduced into the cooling air chamber of the cooling cylinder 76 through the cooling holes 83 again, and thus the cooling duct 78 ) And the cooling pipe 79 are sequentially discharged to the outside.

In addition, due to the relationship of the reactor head 61 to the reactor pressure vessel 6 by the studs 62, the side of the pressure vessel 6 is prevented to prevent heat from leaking out through the coupling portions. The heat insulating material 9 is installed over the lower periphery of the ring 65 and the cylinder 81. That is, the heat insulating material (9) is located inside the support rods 77, the inward flange 91 of the upper end of the heat insulating material (9) is coupled to the outer circumferential surface of the cylinder 81 in the lower position of the cooling cylinder 76, the heat insulating material The lower end of (9) is fixed to the upper side ring (65) of the pressure vessel (6), thereby preventing heat from escaping to the outside between the coupling portion between the reactor head (61) and the reactor pressure vessel (6).

In the conventional reactor superstructure constructed as described above, since it is generally structurally complicated and enlarged, it is very difficult to handle, and the dismantling procedure for reloading the nuclear fuel rod is complicated.

That is, under the structure in which the cooling cylinder 76 constituting the cooling device 75 surrounds the outermost part of the upper structure, not only the cooling cylinder 76 but also the cylinder 81, the cooling duct 78, and the cooling piping 79. In addition, since the connection part thereof has to be enlarged and the cooling cylinder 76 is fixed to the cylinder 81, it is basically fixed in a difficult sealing assembly structure, so that the reactor head (for nuclear reactor maintenance or nuclear fuel rod reloading) is fixed. 61) During the lifting operation, it is very difficult to dismantle the cooling unit 75 including the cooling cylinder 76.

In the disassembling process of the cooling device 75, the long cooling pipe 79 extending to the far upper portion of the reactor head 61 must be dismantled for each element, as well as the connection portion between the cooling cylinder 76 and the cooling duct 78. In addition, the connection portion between the cooling pipe 79 and the cooling duct 78 must be dismantled, and since the sealed assembled cooling cylinder 76 must also be dismantled from the cylinder 81, a lot of time is required to dismantle the cooling device 75. And manpower is required.

In addition, if the cooling head 75 is reinstalled after maintenance work or reloading of nuclear fuel rods by lifting the reactor head, the components of the disassembled cooling device 75 need to be reassembled and reinstalled as well. In order to prevent leakage of radiation, radiation, etc., the sealing work for the cooling air pressure boundary part should be additionally performed, thereby increasing the amount of incidental work.

In addition, in the conventional reactor superstructure, the heat insulating material 9 must also be dismantled in order to lift the reactor head 61. Therefore, in the process of dismantling the heat insulator 9, after removing the upper inward flange 91 of the heat insulator 9 from the cylinder 81, it is necessary to perform the work of separating and removing the heat insulator 9 into pieces. It takes a lot of time and manpower to dismantle the insulation (9).

Moreover, since there is no means for preventing the studs 62 from scattering and it takes a long time to dismantle the cooling device 75 and the heat insulator 9, the human body is exposed to the human body by an increase in the radiation exposure during the dismantling process. There is a risk of adverse effects, which will also be undesirable in terms of safety.

In addition, when the reactor head 61 is lifted, not only the pin coupling portion between the cylinder 81 and the lifting columns 85 but also the pedestal 64 portion of the reactor head 61 may depend on the weight of the reactor head 61 being lifted. The stress is excessively concentrated at the bolt joint with the lower outward flange 82 of the cylinder 81. Therefore, since the stress concentration region is extremely fragile, the membrane stress and moment are stressed at the stress concentration site by expanding the reactor head 61 due to earthquake or reactor operating power and operating pressure not only during the lifting operation of the reactor head 61 but also during operation. Is greatly applied, and the load by self weight is also simultaneously received, further reducing the reliability in terms of safety. As the capacity of the reactor increases, the stress concentration region becomes more vulnerable due to the relation that the size of the cylinder 81 also increases, so that the safety is further lowered, and thus a structure capable of reinforcing it is required.

The present invention provides a compact reactor top structure that can easily lift the reactor head by simplifying maintenance and minimizing dismantling operations when lifting the reactor head by compactizing complex reactor top structures in a compact form. The purpose.

It is another object of the present invention to provide a dense reactor superstructure that can be safely lifted when lifting the reactor head by preventing studs for coupling the reactor head to the reactor pressure vessel from being scattered during reactor operation.

1 is a front view schematically showing a part of the superstructure according to the present invention.

Figure 2 is a plan view showing the main portion of the superstructure according to the present invention.

Figure 3 is a front sectional view showing the main portion of the superstructure according to the present invention.

4 is an enlarged perspective view illustrating part IV of FIG. 3.

5 is a front view schematically showing a part of the conventional superstructure cut out.

<Explanation of symbols for main parts of drawing>

1: Reactor pressure vessel 2: Control rod coil cooling device

3: control rod drive device 4: lifting device

5: By-product Firewall 11: Reactor Head

12: side ring 13: nozzle

14: pedestal 17: eye bolt

18: stud 19, 42: coupling pin

21: cylinder 22, 52: outward flange

23: support plate 24: cooling guide

25: cooling branch 26: guide groove

27: cooling duct 28: cooling piping

31: control rod coil 41: lifting column

51: inward flange 53: notch

54: insulation

In order to achieve the above object, the reactor superstructure according to the present invention has a plurality of control rod coils installed on top of the nozzles to elevate them by energization while wrapping control rod extension shafts extending up through the nozzles above the reactor head. In a reactor superstructure comprising a control rod drive of the reactor, and a reactor head lifting device installed above the reactor head for lifting the reactor head, and a cooling device for cooling the control rod coils,

The control rod coil cooling device is supported on a control rod coil cooling guide tube support plate installed on the upper end of the cylinder so that the lower end is detachably coupled to a ring-shaped pedestal installed around the reactor head, and the control rod driving device penetrates the control rod coil. A plurality of control rod coil cooling guide tubes forming a cooling air passage communicating with the inside of the cylinder between the control rod coils and the inner circumferential surface of the cylinder, and a cooling branch pipe installed along the upper circumference of the cylinder and communicating with the inside of the cylinder; A plurality of cooling ducts are installed to communicate with the cooling branch pipes along the upper surface of the cooling branch pipe, and a plurality of cooling pipes connected to the upper portions of the cooling ducts to communicate with the cooling ducts and extending upward. have;

The lifting device is characterized in that it has three lifting columns which are vertically installed along the outer circumferential surface three directions of the cylinder, the lower end is detachably fixed to the reactor head three directions.

According to the present invention, the inward flange at the top is detachably coupled to a ring-shaped pedestal installed around the reactor head, so as to wrap around the reactor head including studs, and the outward flange at the bottom is detachably removable along the reactor side ring circumference. Combined fly ash barriers may be further included. In addition, a heat insulating material is integrally attached to the inner circumferential surface of the fly protection barrier, and the barrier is preferably made of a structure that can be easily separated with the heat insulating material radially for at least three or more.

In addition, according to the present invention, the ring-shaped pedestal is installed along the circumference of the outer circumferential surface of the reactor head. The ring-shaped pedestal has a vertical ring substantially attached to the upper end of the vertical ring along the reactor head circumference, and a horizontal ring integrally attached to the upper end of the vertical ring, wherein the lower outward flange of the cylinder and the upper inward flange of the protection wall are detachable. Possibly combined.

Further, according to the present invention, guide grooves are formed in a vertical direction in three directions on the outer circumferential surface of the cooling branch pipe, and the lifting columns are inserted from the top to the bottom of the guide grooves so that the bottom of the lifting column is detachably coupled to the reactor head. do.

Further, according to the present invention, a plurality of coupling pins protrude upward along the upper surface of the side ring protruding outward along the upper outer circumferential surface of the reactor pressure vessel, in the lower outward flange of the barrier so that the coupling pins are detachably inserted. A plurality of notches corresponding to the coupling pins are formed.

According to the reactor superstructure of the present invention configured as described above, the heat generated in the control rod coil during the operation of the reactor is cooled by the drive of the cooling fan installed in the cooling pipe of the cooling device. That is, the control rod coil is cooled while the cooling air flows into the cylinder through the cooling air passage formed between the guide tube and the control rod coil by the suction force driven by the cooling fan, and the cooling air flows into the cylinder. Is discharged to the outside through the cooling branch pipe, the cooling ducts and the cooling pipes in sequence.

When reloading or maintaining nuclear fuel rods by shutting down the reactor, first remove the top inward flange of the barrier from the ring-shaped pedestal, then divide the barrier radially into sections and then remove them. When the barrier is lifted up, the bottom outward flange of the barrier is connected to the side ring of the reactor pressure vessel by notches and coupling pins, so that the notches are not interfering with the coupling pins, so the barrier is easily lifted up to separate the bottom of the barrier separately. You don't have to do anything. In addition, since the insulation is integrally attached to the barrier in the process of dividing the barrier into several parts, the insulation is equally divided with the barrier, and the insulation can be removed together with the barrier during the removal of the barrier. It is omitted.

According to the present invention, since the control rod coil cooling device is compactly installed and the lower ends of the lifting columns are directly pinned to the eye bolts of the reactor head, the reactor head is removed from the reactor head by removing the barrier and removing the studs. The lifting operation of the reactor head can be carried out by raising the lifting columns via a lifting frame with a crane without having to disassemble the chiller further after creating a condition that can be separated from the cooling device. As such, when the dismantling time is reduced, the radiation exposure during the dismantling process is reduced, so that the dismantling work can be safely performed. In addition, the lifting columns are directly connected to the reactor head during the lifting of the reactor head, so that the lifting weight of the reactor head and the cooling device can be safely supported.

Other features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings.

As shown in FIG. 1, the reactor superstructure according to the present invention is installed on the nozzles 13 protruding above the reactor head 11 and has control rod coils 32 for elevating a control rod (not shown). Drives 3, a reactor head lifting device 4 installed above the reactor head 11 to lift the reactor head 11, and a cooling device 2 for cooling the control rod coils 32. )

The side ring 12 protrudes outward from the upper outer circumferential surface of the pressure vessel 1. Nozzles 13 protrude upward from the reactor head 11, and the reactor head 11 can be attached to or detached from the upper end of the pressure vessel 1 by the plurality of studs 18. It is coupled to cover the upper portion of the reactor pressure vessel (1).

In addition, a ring-shaped pedestal 14 protruding upward in a ring shape is provided around the outer circumferential surface of the reactor head 11 so that the nozzles 13 are located inward.

According to the present invention, as shown in FIG. 3, the pedestal 14 is integrally installed at the upper end of the vertical ring 15 and the vertical ring 15 which is coupled to the lower end of the reactor head 11 and protrudes upward. Has a horizontal ring 16. The lower end of the vertical ring 15 of the pedestal 14 is preferably permanently coupled to the reactor head (11).

In addition, according to the present invention, three eye bolts 17, 17, and 17 are coupled at equal intervals around the reactor head 11 at the outer bottom of the pedestal 14 (here, both eye bolts are installed for convenience. Shown). These eye bolts 17 are also preferably permanently coupled to the reactor head 11 like the pedestal 14.

On the other hand, reference numeral 2 is a control rod coil cooling device constituting the upper structure according to the present invention, as shown in Figure 1 and 2, the cylinder 21, the control rod coil cooling guide tube 24, and cooling It has a branch pipe 25, a cooling duct 27, and a cooling pipe 28.

The cylinder 21 has an outward flange 22 formed at the bottom thereof to be coupled to the pedestal 14 so as to surround the entire circumference of the nozzles 13 together with the pedestal 14. The internal space of 14 serves as a cooling air chamber. The lower outward flange 22 of the cylinder 21 is preferably detachably fastened by fastening means such as bolts so as to be detachable from the pedestal 14.

Further, according to the present invention, the control rod coil cooling guide tube support plate 23 is detachably coupled to the upper end of the cylinder 21, so that the inside of the cylinder 21 and the pedestal 14, ie, the cooling air chamber, is supported on the support plate 23. Is covered. The support plate 23 extends from the control rods (not shown) installed inside the pressure vessel 1 so that the control rod extension shafts (not shown) protruding upward through the nozzles 13 can penetrate upwardly and upwardly. . In addition, motor housings (not shown) and upper housings 31 are installed on the top of the nozzles 13 in order from the bottom to surround the control rod extension shafts, and control rod coils 32 are disposed around the motor housings. Installed to form the control rod drive (3).

Therefore, when the control rod coil 32 is energized, the magnetic force generated at this time acts as a power source for elevating the extension shaft, thereby substantially elevating the control rod into the core.

The cooling guide tubes 24 surrounding the control rod coils 32 are supported on the upper surface of the support plate 23. The cooling guide tube 24 is preferably sealed and supported by the support plate 23 so as to form a cooling air passage communicating with the internal cooling air chamber of the cylinder 21 between it and the control rod coil 32. Since the structure is the same as, the detailed description thereof is omitted here.

According to the present invention, as shown in Figures 1 and 2, along the upper circumference of the cylinder 21, the cooling branch pipe 25 is installed in the form of a ring to communicate with the inside of the cylinder 21. In addition, cooling ducts 27 communicating with the cooling branch pipe 25 are installed along the upper portion of the cooling branch pipe 25. The cooling branch pipe 25 is preferably detachably coupled to the cylinder 21, and the cooling ducts 27 are also preferably detachably installed in the cooling branch pipe 25.

Here, as illustrated in FIG. 2, three cooling ducts 27 are provided along the upper surface of the cooling branch pipe 25 at equal intervals. As shown in FIG. 1, the cooling duct 27 is bent in an inverted form of the U shape, and both ends of the cooling duct 27 are connected to the cooling branch pipe 25 so that the cooling duct 27 and the cooling powder are cooled. The engines 25 communicate with each other. The lower end of the cooling pipe 28 is connected to the upper surface of the central portion of the cooling duct 27 so as to communicate with the cooling duct 27, and the cooling fan 28 is not shown in the cooling pipe 28 extending upward. It is built.

Therefore, when the cooling fan is driven, the cooling air flows into the internal cooling air chamber of the cylinder 21 through the space between the guide tubes 24 and the control rod coils 32 as shown by the arrows in FIG. 1. In the process, the control rod coils 32 may be cooled. In addition, the cooling air introduced into the cylinder 21 passes through the cooling branch pipe 25, the cooling ducts 27, and the cooling pipe 28 in order to be discharged to the outside.

Further, according to the present invention, the guide grooves 26 are vertically installed in the three outer circumferential surfaces of the cooling branch pipe 25 in order. The vertical guide grooves 26 are preferably installed at positions between the cooling ducts 27, and the three lifting columns 41, 41, and 41 constituting the lifting device 4 through the vertical guide grooves 26. It is inserted downward from the top and the bottom is detachably pinned by the coupling pin 42 to the eye bolts 17 permanently coupled to the reactor head 11.

On the other hand, reference numeral 5 denotes a fly-by-fire barrier for preventing the accident from spreading because the studs 18 fastening the reactor head 11 to the pressure vessel 1 due to an accident, are shown in Figs. As shown, the inward flange 51 is formed at the upper end through the central portion of the upper surface, and the outward flange 52 is formed at the lower end.

The upper inward flange 51 of the fly protection barrier 5 is detachably coupled to the pedestal 14 of the reactor head 11. Strictly, the inward flange 51 is detachably coupled to the horizontal ring 16 of the pedestal 14. The coupling structure between the inward flange 51 and the horizontal ring 16 is preferably made of a coupling structure of the quick release form to facilitate separation.

And, as shown in Figures 2 to 4, the lower outward flange 52 of the barrier wall (5) is detachably inserted coupling pins 19 installed along the upper surface of the side ring 12 of the pressure vessel (1). A plurality of notches 53 are installed corresponding to the coupling pins 19 so as to be possible. If the studs 18 are scattered upward by accident during operation of the reactor, due to the relationship that the inward flange 51 of the barrier 5 is coupled to the pedestal 14, the barriers 5 due to the scattering force of the studs 18 The outgoing flange 52 receives a force to radially deviate due to the impact of), but since the notches 53 are caught in the engagement pins 19 and cannot be detached, the barrier wall 5 is the original coupling. You can keep it as it is.

In addition, in order to easily dismantle the barrier 5 during the lifting operation of the reactor head 11, the barrier 5 is preferably made of a structure that can be easily separated radially by at least three or more. Accordingly, when dismantling the barrier wall 5, the barrier wall 5 may be divided into several parts and removed in a state in which the upper inward flange 51 of the barrier wall 5 is separated from the pedestal 14 of the reactor head 11. That is, the lower outward flange 52 of the barrier wall 5 is coupled to the upper side ring 12 of the pressure vessel 1 by the notches 53 and the coupling pins 19 so as not to separate the work. Even if the barrier 5 is only lifted up, it can be easily separated from the upper side ring 12 of the pressure vessel 1. Therefore, by dividing the security barrier 5 into several equal parts and lifting the separated security barriers 5, the security barrier 5 can be easily removed.

In addition, according to the present invention, a heat insulating material 54 is provided on the inner peripheral surface of the protective wall (5). The heat insulator 54 is to block the heat from escaping through the gap between the coupling portion between the pressure vessel 1 and the reactor head 11, and is preferably integrally attached to the protective wall 5. If the heat insulator 54 is formed integrally with the barrier wall 5, the heat insulator 54 together with the barrier wall 5 may be simultaneously separated in the process of separating the barrier wall 5 into several parts when dismantling the barrier wall 5. It is possible to reduce the dismantling process of the protective wall (5).

Although heat may escape through the gap between the side ring 12 of the pressure vessel 1 and the lower outward flange 52 of the barrier wall 5, the lower end of the heat insulating material 54 may be caused by its own weight. Since the gap is blocked by being pressed against the side ring 12 of), it is possible to prevent the heat from escaping to the outside.

Next, the operation of the reactor superstructure according to the present invention configured as described above will be described.

The control rod drive devices 3 are driven to control the output of the reactor during reactor operation. The control rod drive device 3 is driven by energization of the control rod coil 3, and the pressure is increased as the extension shaft inside the upper housing 31 is lifted by a magnetic force generated when the control rod coil 3 is energized. The output of the reactor is controlled by the elevating of the control rod assembly connected to the extension shaft inside the vessel 1.

When the control rod drive device 3 is driven, high temperature heat is generated in the control rod coil 32, and the high temperature heat is cooled by the control rod coil cooling device 3. That is, when driving the cooling fan installed in the cooling pipe 28, the cooling air cylinder 21 through the cooling air passage formed between the guide tube 24 and the control rod coil 32 by the suction force of the cooling fan. The heat exchange is made in the process flowing into the coil 32 is air-cooled. The air introduced into the cylinder 21 passes through the cylinder 21 and the cooling branch pipe 25, the cooling ducts 26, and the cooling pipes 27 communicating with each other and is discharged to the outside.

If the reactor head 11 is to be lifted to shut down the reactor and reload the nuclear fuel rod or perform maintenance, first release the upper inward flange 51 of the barrier wall 5 from the horizontal ring 16 and ring-shaped. In a state where it can be separated from the pedestal 14, the protective wall 5 is divided into several radial portions and then removed.

When the separated barrier walls 5 are lifted up, the lower outward flange 52 of the barrier wall 5 is connected to the side ring 12 of the reactor pressure vessel 1 by the notches 53 and the coupling pins 19. Since the notches 53 do not interfere with the coupling pins 19 because they are coupled, the barrier 5 is easily lifted up, so that the lower outward flange 52 of the barrier 5 is connected to the side ring of the pressure vessel 1. Separation from (12) does not have to be carried out. In addition, the insulating material 54 is integrally attached to the protective wall 5 in the process of dividing the protective wall 5 into several equal parts, so that the insulating material 54 is also integrally attached to the protective wall 5 together with the protective wall 5. Can be separated into equal parts. In addition, since the insulating material 54 is attached to the protective wall 5 at the time of removing the protective wall 5, the insulating material 54 can be removed together with the protective wall 5. The operation can be omitted.

On the other hand, according to the present invention, the control rod coil cooling device (2) is compactly installed in the upper portion of the reactor head (11) and the lower end of the lifting column 41 is the eye bolt (permanently coupled to the reactor head 11 ( 17 are coupled to each other by direct coupling pins 42, and after removing the barrier wall 5, the studs 18 are removed to create a state where the reactor head 11 can be separated from the reactor pressure vessel 1 The lifting operation of the reactor head 11 can be performed simply by lifting the lifting columns 41 through a lifting frame (not shown) with a crane (not shown) without additional disassembly of the cooling device 2. have.

Further, according to the present invention, the cylinder 21 is detachably coupled from the pedestal 14 of the reactor head 11 and the cooling branch pipe 25 of the cooling device 2 is detachable from the cylinder 21. The cooling duct 27 is also coupled to the cooling branch pipe 25 so as to be detachable from the cooling branch pipe 25 so that it may be considered to separate them from the upper part of the reactor head 11 and then lift the reactor head 11. Except in special cases, it is not necessary to separate them from the top of the reactor head 11, and lifting the reactor head 11 with the cooling device 2 in the combined state can reduce the work force or lifting time.

In the process of lifting the reactor head 11, the lifting columns 41 are directly connected to the reactor head 11 through the eye bolts 17, so that the lifting weights of the reactor head 11 and the cooling device 2 can be safely supported. Can be.

After the lifting of the reactor head 11 is completed, if necessary, the lifting columns 41 or the cooling device 2 are separated from the upper part of the reactor head 11 to perform the remaining necessary work, and after the reloading of the nuclear fuel rod, the above-described process In the reverse order of coupling the reactor head (11) to the pressure vessel (1).

Effects of the reactor superstructure according to the present invention configured as described above are as follows.

First, the lifting operation of the reactor head 11 can be completed by only lifting the lifting columns 41 by a crane without having to dismantle the barrier 5 and then dismantling other components such as the cooling device 2. Therefore, the lifting operation is easily made, as well as the work force and work time can be reduced, and conversely, the operation of coupling the reactor head 11 back to the pressure vessel 1 can be easily performed.

Second, the addition of the fly-by-wall (5) can prevent the spread of the studs 18 during the operation of the reactor to prevent the spread of the accident, when dismantling the barrier (5) the upper inward flange 51 from the ring-shaped pedestal 14 By dividing the barrier 5 into radial equal parts and then removing it, the insulation 54 installed inside the barrier 5 can be removed at the same time, thus reducing the manpower and time required to dismantle the barrier 5. In addition, due to the simple operation can reduce the radiation exposure during the process to improve the safety.

Third, since the control rod coil cooling device 2 can be installed compactly and quickly on the reactor head 11 in a dense structure, the installation cost and maintenance cost of the upper structure can be reduced.

Fourth, since the cylinder 21 forming the cooling air chamber is not directly coupled to the reactor head 21, the film stress and moment during expansion of the reactor head 11 during the operation of the reactor hardly act on the cylinder 21. In addition, the lifting columns 41 are directly connected to the reactor head 11 so that the lifting load does not apply to the cylinder 21 at all during the lifting operation of the reactor head 11. In addition, the safety during the operation of lifting the reactor head 11 is improved.

Claims (6)

Numerous control rod drives with control rod coils mounted on top of the nozzles to elevate the control rod extension shafts extending upward through the nozzles above the reactor head and to elevate them by energization; In the nuclear reactor upper structure comprising a reactor head lifting device for lifting and a cooling device for cooling the control rod coils, The control rod coil cooling device is supported on a control rod coil cooling guide tube support plate installed on the upper end of the cylinder so that the lower end is detachably coupled to a ring-shaped pedestal installed around the reactor head, and the control rod driving device penetrates the control rod coil. A plurality of cooling guide pipes forming a cooling air passage communicating with the inside of the cylinder between the control rod coils and the inner circumferential surface while enclosing them, a cooling branch pipe installed along the upper circumference of the cylinder and communicating with the inside of the cylinder, and the cooling A plurality of cooling ducts installed in communication with the cooling branch pipe along the upper surface of the branch pipes, and a plurality of cooling pipes connected to an upper portion of the cooling ducts so as to communicate with the cooling ducts, and having a cooling fan embedded therein; The lifting device has three lifting columns installed vertically along three outer circumferential surfaces of the cylinder and having a lower end detachably fixed to three directions of the reactor head; And The inward flange of the upper end is coupled to the ring-shaped pedestal so as to surround the reactor head including studs for coupling the reactor head to the reactor pressure vessel, and the outward flange at the bottom is detachable along the upper side circumference of the reactor pressure vessel. Dense reactor upper structure having a fly ash protection function, characterized in that it further comprises a fly ash barrier coupled to. According to claim 1, A plurality of coupling pins protrude upward along the upper surface of the upper side ring of the reactor pressure vessel, and the notch portion corresponding to the coupling pins in the lower outward flange of the barrier wall so that the coupling pins are detachably inserted A plurality of nuclear reactor upper structure having a fly ash protection function, characterized in that the plurality is formed, the upper inward flange of the barrier is detachably coupled to the pedestal. According to claim 1 or 2, wherein the insulating material is integrally installed on the inner circumferential surface of the protective wall, the protective wall is constructed by a structure that can be separated radially separated with the insulating material for at least three or more times. Dense reactor superstructure with function. According to claim 1, wherein the guide grooves are formed in the vertical direction in the three outer circumferential surface of the cooling branch pipe in turn, and the lifting columns are removably inserted from the top to the bottom so that the lower end of the lifting column is removable to the reactor head. Dense reactor upper structure having a fly ash protection function, characterized in that coupled to. The method of claim 4, wherein the three eye bolts are permanently coupled along the circumference of the reactor head below the outside of the ring-shaped pedestal, and the lower ends of the lifting columns are in turn pinned to the eye bolts. Dense reactor superstructure with product protection. 5. The cooling duct of claim 4, wherein both ends of the cooling duct are bent in an inverted U shape on the upper surfaces of the cooling branch pipes between the guide grooves and connected to the cooling branch pipes. Dense reactor upper structure having a fly ash protection function, characterized in that the lower end of the cooling pipe is connected to.