JP2018091710A - Reactor water level detection device and nuclear reactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reactor water level detection device and a nuclear reactor which improve workability of maintenance work on the nuclear reactor.SOLUTION: A reactor water level detection device includes: a water level gauge 41 for detecting a water level of a primary coolant; and a storage pipe 42 for storing the water level gauge 41. In the storage pipe 42, a lower part is supported by a support pipe 61 fixed to an upper core plate 20, and an upper part is supported detachably from a nozzle stub 62 of a reactor vessel lid 13 by a clip 66.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a reactor water level detection device for detecting the coolant level in a nuclear reactor, and a reactor equipped with the reactor water level detection device.

  For example, in a nuclear power plant, a pressurized water reactor uses light water as a reactor coolant and a neutron moderator, turns it into high-temperature and high-pressure water that does not boil throughout the core, and sends this high-temperature and high-pressure water to a steam generator to supply water. The steam is generated by exchanging heat with the steam, and the steam can be sent to a turbine generator to generate power.

  In this pressurized water reactor, a core is provided in a reactor vessel, and this core is composed of a large number of fuel assemblies. By inserting control rod clusters into the fuel assemblies, The reactor power can be controlled. After the coolant (light water) is supplied into the reactor vessel from the inlet nozzle, it descends, reverses at the bottom, and is heated by cooling the fuel as it rises along the fuel assembly. It is discharged and sent to a steam generator. Further, the pressurized water reactor is provided with a water level detection device for detecting the coolant level in the reactor vessel.

  As a water level detection device for detecting the water level of the coolant in the reactor vessel, for example, there is one described in the following patent document. In each of the water level detection devices described in each patent document, an intermediate portion is supported by an upper core support plate, a lower portion is supported by an upper core plate, and an upper portion is supported by a reactor vessel lid.

No. 03-001768 Japanese Patent Laid-Open No. 08-220284

  By the way, when maintaining the nuclear reactor, after removing the reactor vessel lid from the reactor vessel main body, operations such as taking out the reactor internal structure and replacing the fuel assembly are performed. The water level detection device is generally configured by inserting a water level meter into a storage member. One of the storage members is supported by a support member installed on the reactor internal structure side, and the other is fixed to the reactor vessel lid. Since the water level gauge measures the water level of the coolant inside the reactor vessel main body, the total length of the water level meter is generally longer than the total length of the reactor vessel lid. Therefore, when the reactor vessel lid is removed from the reactor vessel with the water level gauge inserted into the storage member during maintenance of the reactor, it is inserted into the storage member when the reactor vessel lid is moved or stored. The water level gauge may come into contact with equipment or equipment installed around the reactor vessel body or maintenance personnel. Pulling out work is required. After the maintenance is completed, it is necessary to reinsert the water level meter into the storage member. The operation of pulling out the water level meter from the storage member or inserting the water level meter into the storage member is an operation that is always necessary for maintenance of the reactor, which increases the maintenance period of the reactor and increases the exposure amount of the operator. It is a problem of increasing.

  The present invention solves the above-described problems, and an object of the present invention is to provide a reactor water level detection device and a reactor that improve the workability of the maintenance work of the reactor.

  In order to achieve the above object, a reactor water level detection device according to the present invention includes a water level meter for detecting the water level of a coolant and a storage member for storing the water level meter. While being supported by a support member provided on the inner structure side, the upper part is detachably supported with respect to the reactor vessel lid.

  Therefore, while the lower part of the storage member is supported by the support member provided on the reactor internal structure side, the upper part is detachably supported by the reactor vessel lid, so that the reactor vessel main body can be removed during the maintenance of the reactor. When the reactor vessel lid is removed, the storage member in which the water level gauge is stored is separated from the reactor vessel lid, so that the operation of pulling out the water level meter from the storage member or inserting the water level meter into the storage member is performed. It becomes unnecessary. Therefore, the work time for the maintenance of the reactor is shortened and the exposure amount of the worker is also reduced, so that the workability of the maintenance work of the reactor can be improved.

  In the reactor water level detection device of the present invention, a nozzle is fixed to the reactor vessel lid, and the storage member has an upper end penetrating the nozzle and is detachably locked by a locking member. It is a feature.

  Accordingly, the storage member can be freely attached to and detached from the reactor vessel lid nozzle simply by operating the locking member, and the reactor vessel lid can be removed by simply raising and lowering the reactor vessel lid with respect to the reactor vessel body. The reactor vessel lid can be attached to the storage member or separated from the storage member.

  In the reactor water level detection device of the present invention, the storage member is provided with a main body portion and an upper small diameter portion, and a stepped portion is provided between the main body portion and the upper small diameter portion. A seal member is interposed between the nozzle and the nozzle.

  Therefore, the seal member is brought into close contact with the storage member and the nozzle by simply moving the stepped portion of the storage member and the nozzle close to each other, and the storage member is locked by the locking member in this tight contact state. It is possible to improve the sealing performance and the seal mounting performance.

  In the reactor water level detection device of the present invention, a support member is fixed to the reactor internal structure, and the storage member is supported by the support member so as to be movable along the longitudinal direction, and the biasing member. Thus, the seal member is biased and supported in the pressing direction.

  Therefore, by moving the storage member upward with respect to the nozzle, the seal member can be brought into close contact with the storage member and the nozzle, and the storage member may be locked by the locking member in this close contact state. Moreover, when the latching member is removed and the latching state of the storage member is released, the storage member descends due to its own weight, but the storage member is supported by the biasing force of the biasing member, so that it collides with the reactor internal structure. Is prevented, and damage to the storage member can be prevented.

  In the nuclear reactor water level detection apparatus according to the present invention, the storage member is supported by the lower end portion thereof being separated from the reactor internal structure by the biasing force of the biasing member.

  Therefore, the amount of movement of the storage member relative to the nozzle can be secured to improve the mounting performance of the seal member, and the impact when the storage member is lowered is reduced by the biasing member to prevent the storage member from being damaged. can do.

  In the reactor water level detection device of the present invention, the support member has a cylindrical shape, and the storage member has a lower end disposed in the support member, and the storage member is interposed between the support member and the storage member. It is characterized in that a positioning member for positioning and holding is provided.

  Accordingly, since the storage member is supported by the support member via the positioning member, the storage member is stably supported at a predetermined position with respect to the reactor internal structure, and the reactor vessel lid can be easily secured. It can be attached to the reactor vessel body.

  Moreover, the nuclear reactor of the present invention is characterized in that the reactor water level detection device is provided.

  Therefore, the water level in the reactor vessel can be detected with high accuracy, and the workability of the maintenance work of the reactor can be improved.

  According to the reactor water level detection device and the reactor of the present invention, the lower part of the storage member for storing the water level gauge is supported by the reactor internal structure, and the upper part is detachably supported by the reactor vessel lid. The workability of the furnace maintenance work can be improved.

FIG. 1 is a cross-sectional view showing a reactor water level detection device of the present embodiment. FIG. 2 is a longitudinal sectional view showing a pressurized water reactor.

  Exemplary embodiments of a reactor water level detection device and a reactor according to the present invention will be described below in detail with reference to the accompanying drawings. In addition, this invention is not limited by this embodiment, and when there are two or more embodiments, what comprises combining each embodiment is also included.

  Although not shown, the nuclear power plant has a reactor and a steam generator disposed in the reactor containment vessel, and a steam turbine power generation facility. The nuclear reactor of the present embodiment uses light water as a reactor coolant and a neutron moderator, and produces high-temperature and high-pressure water that does not boil over the entire core, and sends this high-temperature and high-pressure water to a steam generator to generate steam by heat exchange. This is a pressurized water reactor (PWR) that generates electricity by sending this steam to a turbine generator.

  FIG. 2 is a longitudinal sectional view showing a pressurized water reactor.

  As shown in FIG. 2, in the pressurized water reactor 10, the reactor vessel 11 has a reactor vessel main body 12 and a reactor vessel lid 13 attached to the upper portion thereof so that the reactor internal structure can be inserted therein. The reactor vessel lid 13 is fixed to the reactor vessel body 12 by a plurality of stud bolts 14 and nuts 15 so as to be opened and closed.

  The reactor vessel main body 12 has a cylindrical shape with an upper part opened and a lower part closed in a hemispherical shape. An inlet nozzle 16 for supplying light water as primary cooling water (coolant) to the upper part, and light water An outlet nozzle 17 for discharging the gas is formed. The reactor vessel body 12 has a reactor core 18 disposed therein, and an upper portion thereof is supported by the inner wall surface of the reactor vessel body 12. The upper core support plate 19 is disposed inside the reactor vessel main body 12, and the upper portion is supported by the upper portion of the core tank 18. The upper core plate 20 is suspended and supported on the upper core support plate 19 by a plurality of core support rods 21.

  A lower core support plate 22 is supported below the reactor core 18, and the outer periphery of the lower core support plate 22 is positioned and supported on the inner wall surface of the reactor vessel body 12 by a positioning member 23. The core tank 18 has a lower core plate 24 supported at the bottom. The core 25 is configured with a large number of fuel assemblies 26 disposed therein, and a large number of control rods 27 are disposed therein. The control rods 27 can be inserted into the fuel assemblies 26. A number of control rod cluster guide tubes 28 are fixed to the upper core support plate 19, and control rods 27 can be inserted therein. The reactor vessel lid 13 has a hemispherical shape, a control rod drive device 29 is disposed, a plurality of control rod cluster drive shafts 30 are inserted into the control rod cluster guide tube 28, and a control rod 27 is connected to the lower end portion. ing. The control rod drive device 29 controls the reactor power by inserting / removing each control rod 27 to / from the core 25.

  The reactor vessel 11 is provided with a water level detection device (reactor water level detection device) 40 that detects the level of light water (primary coolant) in the reactor vessel 11. The water level detection device 40 penetrates through the upper core support plate 19 as an in-reactor structure and is supported by the upper core plate 20 and is detachable from the reactor vessel lid 13.

  FIG. 1 is a cross-sectional view showing a reactor water level detection device of the present embodiment.

  As shown in FIG. 1, the water level detection device 40 includes a water level meter 41 that detects the water level of the primary coolant, and a storage pipe (storage member) 42 that stores the water level meter 41.

  The water level meter 41 is generally called, for example, a heating type thermocouple type. Although not shown in the drawing, the water level meter 41 is composed of a plurality of thermocouples having different lengths, and the plurality of thermocouples indicate the coolant temperature at different heights in the primary coolant stored in the reactor vessel 11. It can be measured. When a sufficient amount of primary cooling water is filled in the reactor vessel 11, each thermocouple measures substantially the same cooling water temperature, and there is substantially no temperature difference. It is determined that water is present in the container 11. On the other hand, when the primary cooling water in the reactor vessel 11 decreases, the temperature of the thermocouple exposed from the primary cooling water rises. Therefore, each thermocouple measures a different cooling water temperature, and a temperature difference is generated. Determines that the water in the reactor vessel 11 has decreased. In addition, although the heating type thermocouple type was applied and demonstrated as the water level meter 41, it is not limited to this system.

  The storage tube 42 has a cylindrical shape having a predetermined length, and the water level gauge 41 is stored in a support hole formed along the longitudinal direction. Although FIG. 1 shows a case in which only one water level meter 41 (thermocouple) is stored in the storage tube 42, a plurality of water level meters are actually stored. The storage tube 42 includes a large-diameter main body 51 having an upper small diameter portion 52 having a smaller diameter than the main body portion 51 and a lower small diameter portion 53 having a smaller diameter than the main body portion 51. An upper stepped portion 54 is formed therebetween, and a lower stepped portion 55 is formed between the main body portion 51 and the lower small diameter portion 53. The upper stepped portion 54 and the lower stepped portion 55 have a ring shape, but are not limited to the ring shape.

  A support tube (support member) 61 is fixed to an upper surface portion of the upper core plate 20 as a support member on the in-furnace structure side. The support tube 61 has a cylindrical shape having the same diameter along the axial direction, and the inner diameter is set larger than the outer diameter of the main body 51 of the storage tube 42. On the other hand, the reactor vessel lid 13 is fixed with a nozzle 62 passing through an attachment hole 13a penetrating in the axial direction. The nozzle 62 is formed in a cylindrical main body 62a, a ring-shaped flange 62b formed in the upper part of the main body 62a, a through hole 62c formed in the center of the flange 62b, and a lower part of the main body 62a. And an enlarged-diameter portion 62d having an umbrella shape.

  The storage tube 42 is supported by a support tube 61 whose lower portion is fixed to the upper core plate 20, while the upper portion is detachably supported with respect to a nozzle 62 fixed to the reactor vessel lid 13.

  That is, the storage tube 42 is positioned and held by the lower end portion of the main body 51 being disposed in the support tube 61 and a leaf spring (positioning member) 63 interposed between the storage tube 42 and the support tube 61. Is done. The leaf spring 63 has a cylindrical shape, the upper flange 63a is disposed at the upper end of the support pipe 61, and a plurality of support pieces 63b suspended from the flange 63a penetrates into the support pipe 61, and enters the outer peripheral surface of the storage pipe 42. Pressing. Therefore, the storage tube 42 is maintained in an upright state at the center position of the support tube 61 with respect to the upper core plate 20 by being pressed toward the center by the support pieces 63b of the leaf spring 63, and is axially It is supported movably along (longitudinal direction).

  The storage tube 42 has a compression coil spring (biasing member) 64 interposed between the lower part and the upper core plate 20. One end of the compression coil spring 64 is pressed against the upper surface of the upper core plate 20, and the other end is pressed against the lower stepped portion 55 of the storage tube 42. Therefore, the storage tube 42 is urged and supported on the upper side in the vertical direction by the urging force of the compression coil spring 64.

  On the other hand, the upper portion of the storage tube 42 is disposed in the nozzle 62, and the upper small diameter portion 52 penetrates the through hole 62c. The storage tube 42 has a ring-shaped seal member 65 interposed between the upper stepped portion 54 and the flange portion 62b of the nozzle 62, and the upper small-diameter portion in a state where the seal member 65 is crushed. 52 is detachably locked to the flange portion 62 b of the nozzle 62 by a clip (locking member) 66.

  In the storage tube 42, when the upper small diameter portion 52 is locked to the nozzle 62, the lower small diameter portion 53 is separated from the upper core plate 20, and a gap is secured between them. At this time, the storage tube 42 is biased and supported in the direction in which the seal member 65 is pressed by the biasing force of the compression coil spring 64.

  Here, the operation of the reactor water level detection device of the present embodiment will be described.

  When the water level detector 40 is attached to the reactor vessel 11, first, with the reactor vessel lid 13 removed from the reactor vessel body 12, first, a leaf spring 63 and a leaf spring 63 are attached to the support tube 61 fixed to the upper core plate 20. A compression coil spring 64 is attached, and the storage tube 42 in which the water level gauge 41 is stored is inserted into the support tube 61. Here, the lower portion of the storage tube 42 is elastically supported by the compression coil spring 64, and the outer peripheral surface is supported by the support tube 61 by the leaf spring 63, thereby positioning in the radial direction. Next, a seal member 65 is attached to the upper stepped portion 54 of the storage tube 42, the reactor vessel lid 13 to which the nozzle 62 is fixed is lowered using a crane, and the upper small diameter portion 52 of the storage tube 42 is moved to the nozzle. The through holes 62 c of the 62 are passed through and placed on the reactor vessel main body 12.

  At this time, since the storage tube 42 is in a lowered position where the compression coil spring 64 is compressed by its own weight, the upper tube portion 42 is raised by using the upper small diameter portion 52 by using a jig (not shown). The seal member 65 located between 54 and the flange 62b of the nozzle 62 is crushed. The storage tube 42 is connected to the nozzle 62 by engaging the clip 66 with the upper small-diameter portion 52 with the seal member 65 being crushed at the raised position of the storage tube 42. Then, the nut 15 (see FIG. 2) is fastened to fix the reactor vessel lid 13 to the reactor vessel body 12.

  On the other hand, when performing maintenance work on the reactor internal structure, first, the nut 15 (see FIG. 2) is loosened to release the fastening of the reactor vessel body 12 and the reactor vessel lid 13 and The clip 66 locked to the small diameter portion 52 is removed, and the connection between the nozzle 62 of the reactor vessel lid 13 and the storage tube 42 is released. At this time, the storage tube 42 is lowered by releasing the locking of the upper small diameter portion 52 with respect to the nozzle 62, but the lower portion is supported by the compression coil spring 64, so that the collision with the upper core plate 20 is prevented. Is prevented.

  Next, the reactor vessel lid 13 to which the nozzle 62 is fixed is lifted using a crane, and the upper small diameter portion 52 of the storage pipe 42 is extracted from the through hole 62 c of the nozzle 62. At this time, the lower portion of the storage tube 42 is elastically supported by the compression coil spring 64 and the outer peripheral surface is supported by the support tube 61 by the leaf spring 63, so that the storage tube 42 is supported by the upper core plate 20 independently. In this state, operations such as removal and replacement of the fuel assembly are performed.

  As described above, the reactor water level detection device according to the present embodiment includes the water level meter 41 for detecting the water level of the primary coolant and the storage pipe 42 for storing the water level gauge 41. While supported by the upper core plate (support member) 20, the upper portion is detachably supported with respect to the reactor vessel lid 13.

  Therefore, when the reactor vessel lid 13 is removed from the reactor vessel body 12 during the maintenance of the reactor, the storage tube 42 is separated from the reactor vessel lid 13 and is stably supported on the upper core plate 20 side. The Since the storage member 42 into which the water level gauge 41 is inserted is separated from the reactor vessel lid, the operation of pulling out the water level gauge from the storage member or inserting the water level gauge into the storage member becomes unnecessary. For this reason, the work time related to the maintenance of the reactor is shortened, and the exposure amount of the worker is also reduced, so that the workability of the maintenance work of the reactor can be improved.

  In the reactor water level detection device of this embodiment, the nozzle 62 is fixed to the reactor vessel lid 13, and the upper end portion of the storage pipe 42 penetrates the nozzle 62 and is detachably locked by a clip 66. Accordingly, the storage tube 42 can be freely attached to and detached from the nozzle 62 of the reactor vessel lid 13 simply by operating the clip 66, and the atomic vessel lid 13 can be moved up and down with respect to the reactor vessel body 12. The reactor vessel lid 13 can be separated from the storage tube 42 or the reactor vessel lid 13 can be attached to the storage tube 42.

  In the reactor water level detection device of the present embodiment, the storage pipe 42 is provided with a main body 51 and an upper small diameter portion 52, an upper stepped portion 54 is provided between the main body 51 and the upper small diameter portion 52, and an upper stepped portion is provided. A seal member 65 is interposed between the nozzle 54 and the nozzle 62. Therefore, the seal member 65 is brought into close contact with the storage tube 42 and the nozzle 62 only by moving the upper stepped portion 54 of the storage tube 42 and the nozzle 62 in a direction approaching each other. What is necessary is just to latch 42 and can improve sealing performance and seal mounting | wearing property.

  In the reactor water level detection device of the present embodiment, the support tube 61 is fixed to the upper core plate 20, and the lower end portion of the storage tube 42 is supported by the support tube 61 so as to be movable along the longitudinal direction. Therefore, the seal member 65 is biased and supported in the direction in which the seal member 65 is pressed. Accordingly, by moving the storage tube 42 upward with respect to the nozzle 62, the seal member 65 can be brought into close contact with the storage tube 42 and the nozzle 62, and the storage tube 42 is locked by the clip 66 in this tight contact state. do it. Further, when the clip 66 is removed to release the locked state of the storage tube 42, the storage tube 42 is lowered by its own weight. However, since the storage tube 42 is supported by the urging force of the compression coil spring 64, the upper core plate 20. Can be prevented and damage to the storage tube 42 can be prevented.

  In the reactor water level detection device of the present embodiment, the storage tube 42 is supported by the urging force of the compression coil spring 64 so that the lower end portion is separated from the upper core plate 20. Accordingly, the amount of movement of the storage tube 42 relative to the nozzle 62 can be secured to improve the mounting performance of the seal member 65, and the impact when the storage tube 42 is lowered is relaxed by the compression coil spring 64 and stored. Damage to the tube 42 can be prevented.

  In the reactor water level detection device of the present embodiment, the support tube 61 has a cylindrical shape, the lower end portion of the storage tube 42 is disposed in the support tube 61, and the storage tube 42 is positioned between the support tube 61 and the storage tube 42. A holding leaf spring 63 is provided. Accordingly, since the storage tube 42 is supported by the support tube 61 via the leaf spring 63, the storage tube 42 is stably supported at a predetermined position with respect to the upper core plate 20, and the reactor vessel The lid 13 can be easily attached to the reactor vessel main body 12.

  Further, in the nuclear reactor of the present embodiment, the reactor water level detection device 40 is provided in the reactor vessel 11. Therefore, the water level of the primary cooling water in the reactor vessel 11 can be detected with high accuracy, and the workability of the maintenance work of the reactor can be improved.

  In the above-described embodiment, the compression coil spring 64 as the urging member is disposed below the storage tube 42 as the storage member. However, the present invention is not limited to this position. For example, a flange portion or a stepped portion is provided in the intermediate portion in the longitudinal direction of the storage member, while a support member is provided with a spring receiving portion, and the biasing member is interposed between the flange portion or the stepped portion and the spring receiving portion. May be. Further, the storage member may be divided into two, and the urging member may be interposed between the upper storage member and the lower storage member. Further, the urging member is not limited to the compression coil spring 64 but may be constituted by a tension spring, a rubber member, a resin member, or the like.

  Further, in the embodiment described above, the water level detection device 40 is supported on the upper core plate 20 as the support member on the reactor internal structure side. However, the support on the other reactor internal structure side such as the upper core support plate 19 is supported. You may comprise so that it may support in a member.

  Moreover, although the nuclear reactor was demonstrated as a pressurized water reactor in embodiment mentioned above, you may apply to a boiling water reactor (BWR: Boiling Water Reactor) and a fast breeder reactor (FBR: Fast Breeder Reactor). .

DESCRIPTION OF SYMBOLS 10 Pressurized water reactor 11 Reactor vessel 12 Reactor vessel body 13 Reactor vessel lid 18 Core tank 19 Upper core support plate 20 Upper core plate (support member)
25 Core 26 Fuel assembly 27 Control rod 40 Water level detection device 41 Water level gauge 42 Storage pipe (storage member)
51 Main body portion 52 Upper small diameter portion 53 Lower small diameter portion 54 Upper stepped portion 55 Lower stepped portion 61 Support pipe (support member)
62 Tubular base 63 Leaf spring (positioning member)
64 Compression coil spring (biasing member)
65 Seal member 66 Clip (locking member)

Claims (7)

A water level gauge that detects the coolant level,
A storage member for storing the water level gauge;
With
The storage member is supported by a support member whose lower part is provided on the reactor internal structure side, while its upper part is detachably supported with respect to the reactor vessel lid.
A reactor water level detection device characterized by that.   2. The atom according to claim 1, wherein a nozzle is fixed to the reactor vessel lid, and an upper end portion of the storage member penetrates the nozzle and is detachably locked by a locking member. Reactor water level detection device.   The storage member is provided with a main body portion and an upper small diameter portion, a stepped portion is provided between the main body portion and the upper small diameter portion, and a seal member is provided between the stepped portion and the nozzle. The reactor water level detection device according to claim 2, wherein the reactor water level detection device is interposed.   A support member is fixed to the in-furnace structure, and the lower end portion of the storage member is supported by the support member so as to be movable along the longitudinal direction, and the seal member is pressed by the biasing member. The reactor water level detection device according to claim 3, wherein the reactor water level detection device is biased and supported.   The reactor water level detection device according to claim 4, wherein a lower end portion of the storage member is supported by the urging force of the urging member so as to be separated from the reactor internal structure.   The support member has a cylindrical shape, the storage member has a lower end portion disposed in the support member, and a positioning member that positions and holds the storage member is provided between the support member and the storage member. The reactor water level detection apparatus according to claim 4 or 5, characterized in that: A nuclear reactor comprising the reactor water level detection device according to any one of claims 1 to 6.

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