Inspection device guide jig and method for installing the inspection device guide jig

Abstract

During internal inspection of a steam generator, access is provided to any inspection point between the heat transfer tubes. [Solution] The inspection device guide jig comprises a flexible rod-shaped guide section, a curveable tubular section extending along the direction of extension of the guide section through which an inspection device is inserted, an expandable / contractible section provided on the outer circumference of the insertion section which expands when fluid is supplied to it and contracts when fluid is discharged from it, and a fluid supply / discharge section which supplies and discharges fluid to and from the expandable / contractible section.

Description

Technical Field

[0001] The present disclosure relates to an inspection device guiding jig and a method for installing an inspection device guiding jig.

Background Art

[0002] Conventionally, a nuclear power plant equipped with a nuclear reactor has a steam generator for generating steam that drives a turbine connected to a generator. In the steam generator, primary cooling water supplied from the nuclear reactor flows inside the heat transfer tubes, and secondary cooling water flows outside the heat transfer tubes. The secondary cooling water is heated by the high-temperature primary cooling water, thereby generating steam.

[0003] By the way, as one of the inspection items of a nuclear power plant, inspection of a tube support plate that supports heat transfer tubes is performed inside the secondary side of a steam generator. For example, Patent Document 1 discloses an inspection device guiding jig including a guiding tube and a rigid tube in which an insertion part and a gas supply part are integrally provided, the guiding tube being deformable when no gas is supplied and having a predetermined shape when gas is supplied.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the conventional guiding jig has a problem that although it can specify the general orientation in which the guiding tube extends by the rigid tube, it is difficult to access an arbitrary position because the guiding tube is made of a flexible material.

[0006] This disclosure aims to solve the aforementioned problems and to provide an inspection device guide jig and a method for installing the inspection device guide jig that can access any inspection position between heat transfer tubes during internal inspection of a steam generator. [Means for solving the problem]

[0007] To achieve the above-mentioned objectives, an inspection device guide jig according to one aspect of the present disclosure comprises: a flexible rod-shaped guide portion; a curved tubular insertion portion extending along the direction of extension of the guide portion, through which an inspection device is inserted; an expandable / contractible portion provided on the outer circumference of the insertion portion, which expands when fluid is supplied to it and contracts when fluid is discharged from it; and a fluid supply / discharge portion for supplying and discharging fluid to and from the expandable / contractible portion.

[0008] To achieve the above objective, a method for installing an inspection device guide jig according to one aspect of the present disclosure includes: a flexible rod-shaped guide portion; a flexible portion having a bendable tubular shape along the extending direction of the guide portion through which an inspection device is inserted; an expandable / contractable portion provided on the outer circumference of the insertable portion, which expands when fluid is supplied to it and contracts when fluid is discharged from it; and a fluid supply / discharge portion for supplying and discharging fluid to and from the expandable / contractable portion; and a non-deformable tubular support portion through which the flexible portion is inserted, formed by curving its tip so that it faces in a direction perpendicular to the axial direction of its base end; and inserting a plurality of heat transfer tubes that extend in the Z direction and are arranged side by side in the X and Y directions inside a steam generator. A method for installing an inspection device guide jig to be installed at a predetermined inspection position for inspecting a pipe support plate that supports a pipe through, comprising: an insertion step of inserting the support portion in the XZ direction from an inspection port of the steam generator; an X-direction positioning step of orienting the tip of the flexible portion in the YZ direction from between adjacent heat transfer tubes in the X direction at a position in the X direction corresponding to the inspection position; an extension step of extending the flexible portion from the support portion in the YZ direction; a Y-direction positioning step of supplying fluid to the expand / contract portion to expand it and positioning it between adjacent heat transfer tubes in the Y direction at a position in the Y direction corresponding to the inspection position; and an installation step of further extending the flexible portion from the support portion so that the tip of the insertion portion reaches the inspection position. [Effects of the Invention]

[0009] According to this disclosure, the effect is obtained that any inspection position between heat transfer tubes can be accessed during internal inspection of a steam generator. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic diagram showing an example of a nuclear power plant. [Figure 2] Figure 2 is a schematic diagram showing the internal configuration of the steam generator. [Figure 3] Figure 3 is a schematic diagram showing the pipe support plate. [Figure 4]Figure 4 is a schematic diagram showing the area where the inspection device guide jig according to the embodiment is installed. [Figure 5] Figure 5 is a cross-sectional view taken along the line AA shown in Figure 4. [Figure 6] Figure 6 is a side view showing the flexible portion of the inspection device guide jig according to the embodiment. [Figure 7] Figure 7 is an axial view of the flexible portion shown in Figure 6. [Figure 8] Figure 8 is a plan view showing the support portion of the inspection device guide jig according to the embodiment. [Figure 9] Figure 9 is a side view of the support section shown in Figure 8. [Figure 10] Figure 10 is a flowchart showing the flow of the installation method for the inspection device guide jig according to the embodiment. [Figure 11] Figure 11 is an explanatory diagram illustrating the installation procedure shown in Figure 10. [Figure 12] Figure 12 is an explanatory diagram illustrating the installation procedure shown in Figure 10. [Figure 13] Figure 13 is an explanatory diagram illustrating the installation procedure shown in Figure 10. [Figure 14] Figure 14 is an explanatory diagram illustrating the installation procedure shown in Figure 10. [Figure 15] Figure 15 is an explanatory diagram illustrating the installation procedure shown in Figure 10. [Figure 16] Figure 16 is an explanatory diagram illustrating the installation procedure shown in Figure 10. [Modes for carrying out the invention]

[0011] Hereinafter, embodiments according to the present disclosure will be described in detail based on the drawings. Note that the present invention is not limited by these embodiments. Further, the constituent elements in the following embodiments include those that can be replaced and are easy for those skilled in the art, those that are substantially the same, or those within an equivalent range. Furthermore, the constituent elements in the following embodiments can be variously omitted, replaced, or changed without departing from the gist of the present disclosure. In the following embodiments, for the purpose of exemplifying the embodiments, necessary constituent elements will be described, and other constituent elements will be omitted. The same reference numerals will be assigned to the same configurations, and different reference numerals will be assigned to different configurations.

[0012] 〔Nuclear Power Plant〕 FIG. 1 is a schematic diagram showing an example of a nuclear power plant. The nuclear power plant 100 shown in FIG. 1 is a pressurized water reactor (PWR). In the reactor containment vessel 110, a reactor pressure vessel 112, a pressurizer 114, a steam generator 200, and a primary coolant pump 116 are sequentially connected by primary coolant pipes 118 and 120 to form a circulation path of the primary coolant.

[0013] The reactor pressure vessel 112 stores a plurality of fuel assemblies 112a, which are the core, in a sealed state inside. The reactor pressure vessel 112 is provided including a vessel main body 112b and a vessel head 112c attached to the upper part of the vessel main body 112b so that the fuel assemblies 112a can be inserted and removed. The vessel head 112c is provided so as to be openable and closable with respect to the vessel main body 112b. The vessel main body 112b has an upward opening and a cylindrical shape that is hemispherical and closed at the bottom. The vessel main body 112b is provided with an inlet side nozzle 112d and an outlet side nozzle 112e for supplying and discharging light water as the primary coolant at the upper part.

[0014] The pressurizer 114 is connected to the primary cooling water pipe 118 and controls it to a high temperature and high pressure so that the primary cooling water does not boil throughout the reactor containment vessel 110. The primary cooling water pump 116 circulates the primary cooling water between the reactor pressure vessel 112 and the steam generator 200. The primary cooling water pipe 118 is connected such that the outlet side header 112e of the reactor pressure vessel 112 and the inlet side water chamber 234 (see FIG. 2) of the steam generator 200 communicate with each other. The primary cooling water pipe 120 is connected such that the outlet side water chamber 236 (see FIG. 2) of the steam generator 200 and the inlet side header 112d of the reactor pressure vessel 112 communicate with each other via the primary cooling water pump 116.

[0015] In addition, in the nuclear power plant 100, the steam generator 200 is located outside the reactor containment vessel 110, and the steam turbine 122, moisture separator reheater 124, condenser 126, condensate pump 128, low-pressure feedwater heater 130, deaerator 132, main feedwater pump 134, and high-pressure feedwater heater 136 are sequentially connected by the secondary cooling water pipes 138 and 140 to form a circulation path for the primary cooling water. A main steam isolation valve 138a is provided in the secondary cooling water pipe 138 on the outlet side of the steam generator 200. A main feedwater valve 140a is provided in the secondary cooling water pipe 140 on the inlet side of the steam generator 200.

[0016] The steam turbine 122 has a high-pressure turbine 122a and a low-pressure turbine 122b, and a generator 122c is connected coaxially thereto. The high-pressure turbine 122a is connected to the secondary cooling water pipe 138 on the inlet side and to the moisture separator reheater 124 on the outlet side. The low-pressure turbine 122b is connected to the moisture separator reheater 124 on the inlet side and to the condenser 126 on the outlet side. The steam turbine 122 is driven by the steam of the secondary cooling water. The generator 122c generates electricity when the power of the steam turbine 122 is transmitted thereto. The moisture separator reheater 124 is further connected by branching from the secondary cooling water pipe 138 on the outlet side of the steam generator 200. The moisture separator reheater 124 receives the exhaust from the high-pressure turbine 122a, removes the moisture, further heats it to a superheated state, and sends the dry steam to the low-pressure turbine 122b.

[0017] The condenser 126 exchanges heat between cooling water (e.g., seawater) taken in by the pump 126b via the intake pipe 126a and steam discharged from the low-pressure turbine 122b, condensing the steam and returning it to a low-pressure saturated liquid. The cooling water used for heat exchange is discharged through the drain pipe 126c. The condensate pump 128 sends the secondary cooling water, which has been returned to a saturated liquid, to the low-pressure feedwater heater 130. The low-pressure feedwater heater 130 heats the secondary cooling water using, for example, low-pressure steam extracted from the low-pressure turbine 122b. The deaerator 132 removes impurities such as dissolved oxygen and non-condensing gases (ammonia gas) from the secondary cooling water heated in the low-pressure feedwater heater 130. The main feedwater pump 134 sends the secondary cooling water, from which impurities have been removed in the deaerator 132, to the high-pressure feedwater heater 136. The high-pressure feedwater heater 136 heats the secondary cooling water, for example, by high-pressure steam extracted from the high-pressure turbine 122a.

[0018] In the nuclear power plant 100, the primary coolant is heated in the reactor pressure vessel 112 to become high temperature and high pressure, and is then pressurized in the pressurizer 114 to maintain a constant pressure before being supplied to the steam generator 200 via the primary coolant pipe 118. In the steam generator 200, heat exchange occurs between the primary coolant and the secondary coolant, causing the secondary coolant to evaporate and turn into steam. The cooled primary coolant after heat exchange is recovered to the primary coolant pump 116 side via the primary coolant pipe 120 and returned to the reactor pressure vessel 112.

[0019] Meanwhile, the secondary cooling water, which has been turned into steam by heat exchange, is used in the steam turbine 122, condensed in the condenser 126, and returned to saturated liquid. The secondary cooling water is sent out of the condenser 126 via the secondary cooling water pipe 140 by the condensate pump 128. Furthermore, the secondary cooling water passing through the secondary cooling water pipe 140 is heated in the low-pressure feedwater heater 130, impurities are removed in the deaerator 132, then it is sent by the main feedwater pump 134, heated in the high-pressure feedwater heater 136, and returned to the steam generator 200 via the secondary cooling water pipe 140. Here, in the secondary cooling water pipe 140, the main feedwater pump 134 and the main feedwater valve 140a, etc., are controlled to maintain the water level of the secondary cooling water in the steam generator 200.

[0020] Although only one steam generator 200 is shown in Figure 1, typically multiple generators are provided, each connected to the reactor pressure vessel 112 and the steam turbine 122.

[0021] [Steam generator] Figure 2 is a schematic diagram showing the internal configuration of the steam generator. Figure 3 is a schematic diagram showing the pipe support plate. Figure 4 is a schematic diagram showing the area where the inspection device guide jig according to the embodiment is installed. Figure 5 is a cross-sectional view taken along the line AA shown in Figure 4. In the following description, a horizontal direction will be referred to as the X direction, a horizontal direction perpendicular to the X direction will be referred to as the Y direction, and a vertical direction perpendicular to both the X and Y directions will be referred to as the Z direction.

[0022] The steam generator 200 is provided, for example, to a nuclear power plant as shown in Figure 1, and exchanges heat between high-temperature primary cooling water heated inside the reactor containment vessel 110 and secondary cooling water supplied from the outside, generating steam from the secondary cooling water and supplying the steam to a steam turbine 122 to generate electricity. As shown in Figure 2, the steam generator 200 comprises a shell 202, a heat exchange section 210, a water chamber mirror 230, a feedwater section 240, a steam-water separator 250, and a moisture separator 260.

[0023] The shell 202 extends vertically (Z-direction) and has a sealed, hollow cylindrical shape, with the lower half being slightly smaller in diameter than the upper half. A steam outlet 204 and an inspection port 206 are formed in the shell 202. The steam outlet 204 is formed at the upper end of the shell 202 and discharges steam generated from the secondary cooling water that has undergone heat exchange with the primary cooling water in the steam generator 200. The secondary cooling water pipe 138 is connected to the steam outlet 204 so as to communicate with the high-pressure turbine 122a (see Figure 1) of the steam turbine 122.

[0024] The inspection port 206 connects the inside and outside of the steam generator 200 and is an opening for inserting the inspection device guide jig 1, described later according to this embodiment, from the outside. The inspection port 206 is provided in the lower half of the body 202 having the heat exchange section 210. As shown in Figure 4, the inspection port 206 is provided on both sides of the body 202, for example, at a position between the lowest pipe support plate 216 and the flow rate distribution plate 218, passing through the inside of the steam generator 200 and facing in the X direction. The inspection port 206 is also provided penetrating the outer pipe assembly 212, described later, and is configured to allow access from the outside of the body 202 to the lower surface of the lowest pipe support plate 216. The inspection port 206 is closed by attaching a lid when the steam generator 200 is in use.

[0025] The heat exchange section 210 is located inside the lower half of the body section 202 and exchanges heat between high-temperature primary cooling water and secondary cooling water. The heat exchange section 210 includes a tube group outer cylinder 212, a tube sheet 214, a tube support plate 216, a flow distribution plate 218, and a heat transfer tube group 220.

[0026] The outer tube casing 212 is formed in a cylindrical shape extending in the Z direction and is positioned at a predetermined distance from the inner circumferential surface of the body portion 202. The lower end of the outer tube casing 212 extends to the vicinity of the tube sheet 214 located at the lower end of the body portion 202. The upper end of the outer tube casing 212 is connected to the lower end of the gas-water separator 250, which will be described later.

[0027] The tube sheet 214 is positioned at the lower end of the heat exchange section 210 and closes the opening at the lower end of the body section 202. The tube sheet 214 has a plurality of tube holes 214a that penetrate in the Z direction. A heat transfer tube 222, described later, is inserted through each tube hole 214a and supports the lower end of the heat transfer tube 222.

[0028] The pipe support plates 216 are attached to the inner circumference of the outer pipe assembly 212 so that their thickness direction is oriented in the Z direction. Multiple pipe support plates 216 (six in the illustrated example) are arranged in a row with spacing in the Z direction. The multiple pipe support plates 216 divide the internal space of the outer pipe assembly 212 into multiple spaces aligned in the Z direction.

[0029] As shown in Figure 3, each pipe support plate 216 has multiple pipe holes 216a and multiple flow slots 216b that penetrate in the Z direction. Each pipe hole 216a is through which a heat transfer tube 222 (described later) is inserted and supports the middle portion of the heat transfer tube 222. The pipe holes 216a of the pipe support plate 216 are formed in the same positions as the pipe holes 214a of the pipe sheet 214 when viewed in the Z direction. The flow slots 216b are formed as elongated holes with a longitudinal direction in the X direction, and are formed in a row at intervals in the X direction at the center of the pipe support plate 216 in the Y direction. The multiple spaces of the outer tube 212 of the pipe group, which are partitioned by the pipe support plates 216, communicate with each other via the flow slots 216b.

[0030] The flow distribution plate 218 shown in Figures 2 and 4 is positioned between the tube sheet 214 and the lowest tube support plate 216, and is attached to the inner circumference of the outer tube assembly 212 such that its thickness direction is oriented in the Z direction. The flow distribution plate 218 divides the space between the tube sheet 214 and the lowest tube support plate 216 in the Z direction. The flow distribution plate 218 has an opening 218a that penetrates in the Z direction. The opening 218a is formed in the center of the flow distribution plate 218 when viewed in the Z direction. When viewed in the Z direction, the size of the opening 218a of the flow distribution plate 218 is larger than the size of the flow slot 216b of the tube support plate 216. The upper and lower spaces divided by the flow distribution plate 218 communicate with each other through the opening 218a.

[0031] The heat transfer tube group 220 is provided on the inner circumference side of the outer tube group cylinder 212. The heat transfer tube group 220 has a plurality of heat transfer tubes 222 that extend in the Z direction in an inverted U shape. The heat transfer tubes 222 form a heat transfer tube layer in which the diameter of the arc portion increases from the center outwards, and by overlapping this heat transfer tube layer and changing the diameter, the upper end of the heat transfer tube group 220 is formed into a hemispherical shape. Each heat transfer tube 222 has its U-shaped arc portion facing upwards, with its lower end inserted and supported in a tube hole 214a of the tube sheet 214, and its middle portion supported by the outer tube group cylinder 212 via a plurality of tube support plates 216.

[0032] As shown in Figure 5, the multiple heat transfer tubes 222 are arranged side by side at predetermined intervals in the X and Y directions. The multiple heat transfer tubes 222 are arranged to avoid the formation areas of the multiple flow slots 216b in the tube support plate 216 and the formation areas of the openings 218a in the flow distribution plate 218. For this reason, the spacing between the heat transfer tubes 222 located on both sides of the flow slot 216b formation area in the Y direction is large in proportion to the size of the flow slot 216b formation area.

[0033] Furthermore, the heat exchange section 210 shown in Figure 2 has a water supply channel 224 through which secondary cooling water supplied to the body section 202 from the water supply section 240 (described later) flows. The secondary cooling water flowing through the water supply channel 224 flows down between the inner circumference of the body section 202 and the outer circumference of the tube group outer cylinder 212, turns back at the tube sheet 214, and rises along the heat transfer tube group 220 while passing through the opening 218a of the flow distribution plate 218 and the flow slot 216b of the tube support plate 216 on the inner circumference of the tube group outer cylinder 212, and reaches the gas-water separator 250.

[0034] The water chamber mirror 230 is formed in a bowl shape, and its opening edge is joined to the tube sheet 214, thereby joining it to the lower end of the shell 202. The inside of the water chamber mirror 230 is divided into an inlet water chamber 234 and an outlet water chamber 236 by a partition plate 232. The inlet water chamber 234 has an inlet pipe support 234a that leads to the outside of the shell 202, and one end of each heat transfer tube 222 is connected to it. The inlet pipe support 234a is connected to the primary cooling water pipe 118 (see Figure 1) that supplies primary cooling water from the reactor containment vessel 110 (see Figure 1). The outlet water chamber 236 has the other ends of each heat transfer tube 222 connected to it, and an outlet pipe support 236a that leads to the outside of the shell 202 is formed therein. The outlet side pipe mount 236a is connected to the primary coolant pipe 120 (see Figure 1), which sends the primary coolant, after heat exchange, to the reactor containment vessel 110.

[0035] The feedwater section 240 has a feedwater pipe 242 located inside the shell 202 above the heat exchange section 210. The feedwater pipe 242 introduces secondary cooling water for heat exchange with primary cooling water in the steam generator 200. A secondary cooling water pipe 140 (see Figure 1) is connected to the feedwater pipe 242 to supply secondary cooling water that has been used in the steam turbine 122 to become steam and then cooled and condensed in the condenser 126 (see Figure 1). The feedwater section 240 introduces secondary cooling water from outside the shell 202 via the feedwater pipe 242 and supplies water from its upper end between the inner circumference of the shell 202 of the heat exchange section 210 and the outer circumference of the outer tube 212 of the tube group.

[0036] The steam-water separator 250 is located in the upper half of the body 202 and separates the secondary cooling water supplied from the water supply channel 224 into steam and hot water. The moisture separator 260 is located in the upper half of the body 202 above the steam-water separator 250 and removes moisture from the steam separated by the steam-water separator 250 to make it close to dry steam. The dry steam is discharged from the steam outlet 204 into the secondary cooling water pipe 138.

[0037] In the steam generator 200, primary cooling water heated in the reactor containment vessel 110 is supplied from the inlet water chamber 234 via the primary cooling water pipe 118 and passes through the inside of multiple heat transfer tubes 222 in the heat exchange section 210. In the heat exchange section 210, heat exchange takes place between the primary cooling water passing inside the heat transfer tubes 222 and the secondary cooling water passing outside, thereby cooling the primary cooling water. The primary cooling water cooled by the secondary cooling water is returned to the reactor containment vessel 110 from the outlet water chamber 236 via the primary cooling water pipe 120.

[0038] Meanwhile, the secondary cooling water, which has been condensed and saturated by the condenser 126, is supplied from the feedwater section 240 via the secondary cooling water pipe 140 and guided between the inner circumference of the shell 202 of the heat exchange section 210 and the outer circumference of the tube group outer cylinder 212. The secondary cooling water, which has been folded back into the interior of the tube group outer cylinder 212 by the tube sheet 214, rises along the heat transfer tube group 220 and outside the heat transfer tubes 222, and is heated by the primary cooling water passing inside the heat transfer tubes 222. The heated secondary cooling water is separated into steam and hot water in the steam-water separator 250, after which moisture is removed from the separated steam in the moisture separator 260, and it is discharged from the steam outlet 204 and sent to the steam turbine 122 via the secondary cooling water pipe 138.

[0039] [Inspection equipment guide jig] Figure 6 is a side view showing the flexible portion of the inspection device guide jig according to the embodiment. Figure 7 is an axial view of the flexible portion shown in Figure 6. Figure 8 is a plan view showing the support portion of the inspection device guide jig according to the embodiment. Figure 9 is a side view of the support portion shown in Figure 8.

[0040] The inspection device guide jig 1 is a jig for guiding an inspection device (not shown) for inspecting the inside of the steam generator 200 to a predetermined inspection position. The inspection device includes, for example, an imaging unit, an image processing unit, and a display unit. The imaging unit is an endoscope that includes, for example, a flexible insertion tube and an image sensor such as a CCD (Charge Coupled Device) and an illumination element such as an LED (Light Emitting Diode) attached to the tip of the insertion tube. The insertion tube preferably has an outer diameter of 6 mm or less and a length of 10 m or more, and is made of a material with excellent sliding properties such as stainless steel mesh. Inside the insertion tube, there are power supply cables to the image sensor and illumination element, and signal cables for transmitting image signals from the image sensor. The image processing unit is connected to the proximal end of the insertion tube and supplies power to the image sensor and illumination element, and processes the image signal from the image sensor as an image signal for display. The display unit is connected to the image processing unit and displays the screen captured by inputting the image signal.

[0041] The inspection device guide jig 1 guides the imaging unit of the inspection device described above to a predetermined inspection position. The inspection device guide jig 1 of this embodiment is inserted through an inspection port 206 located below the flow rate distribution plate 218 of the steam generator 200 shown in Figure 4, etc., and inspects the lower surface of the lowest pipe support plate 216 by passing through the opening 218a of the flow rate distribution plate 218. The inspection device guide jig 1 comprises a flexible part 10 shown in Figures 6 and 7, a support part 20 shown in Figures 8 and 9, and a fixed part (not shown).

[0042] The flexible portion 10 shown in Figures 6 and 7 is a part that protrudes in the Y direction relative to the support portion 20 when the inspection device guide jig 1 accesses a predetermined inspection position inside the steam generator 200 of the embodiment, and is used for positioning in the Y direction. The flexible portion 10 is a rod-shaped elastic body with flexibility. The base end of the flexible portion 10 is housed and supported in the support portion 20, and is provided so as to be able to extend and retract from the outlet hole 26a of the orientation changing portion 24 of the support portion 20, which will be described later. As shown in Figures 6 and 7, the flexible portion 10 has a guide portion 12, an insertion portion 14, a fluid supply and discharge portion 16, and an expandable and contractible portion 18.

[0043] The guide portion 12 is a flexible rod-shaped elastic body. The guide portion 12 may also be tubular, such as a urethane tube. The guide portion 12 provides the rigidity of the flexible portion 10 as a whole and supports the insertion portion 14 and the fluid supply and discharge portion 16.

[0044] The insertion portion 14 is flexible and is provided in a tubular shape along the extending direction of the guide portion 12. The imaging unit of an inspection device (not shown) is inserted into the insertion portion 14, and an image sensor is positioned at the tip portion 14a. The insertion portion 14 is preferably made of a Teflon® tube or the like, which has excellent sliding properties, and is provided to be bendable. The insertion portion 14 has lower rigidity than the guide portion 12. In this embodiment, the insertion portion 14 is fixed, for example, by a fixing tape 12a so that its extending direction is parallel to the extending direction of the guide portion 12. The insertion portion 14 may also be used in conjunction with the guide portion 12.

[0045] The fluid supply and discharge section 16 is flexible and is provided in a tubular shape along the extending direction of the guide section 12 and the insertion section 14. The base end of the fluid supply and discharge section 16 is connected to a fluid supply source (not shown), and the tip is closed, allowing fluid to flow inside. The fluid is preferably a gas, such as air, but may also be a liquid. The fluid supply and discharge section 16 of the embodiment has a small-diameter section 16a in a predetermined length portion including the tip, which has a smaller diameter than the rest of the section. The small-diameter section 16a penetrates the expandable / contractible section 18 and has a supply / discharge port 16b, which is an opening that communicates with the inside of the expandable / contractible section 18. The fluid supply and discharge section 16 supplies fluid to the inside of the expandable / contractible section 18 via the supply / discharge port 16b and sucks fluid from the inside of the expandable / contractible section 18 and discharges it.

[0046] The fluid supply and discharge section 16 is preferably made of, for example, a urethane tube and is provided in a flexible manner. The fluid supply and discharge section 16 may be two or more tubes bonded to the guide section 12. The fluid supply and discharge section 16 has lower rigidity than the guide section 12. In the embodiment, the fluid supply and discharge section 16 is fixed, for example, by fixing tape 12a, sandwiched between the guide section 12 and the insertion section 14, such that its extending direction is parallel to the extending direction of the guide section 12 and the insertion section 14. The fixing tape 12a is composed of, for example, an ultra-high molecular weight polyethylene tape that wraps around and fixes the guide section 12, the insertion section 14 and the fluid supply and discharge section 16 together, and a Nitoflon® tape that is wrapped over and covers the ultra-high molecular weight polyethylene tape. The fluid supply and discharge section 16 may also be used in conjunction with the guide section 12.

[0047] The expandable / contractible portion 18 is provided on the outer circumference near the tip portion 14a of the insertion portion 14. The expandable / contractible portion 18 is flexible and expands when fluid is supplied to the interior from the fluid supply / discharge portion 16, and contracts when fluid is discharged from the interior to the fluid supply / discharge portion 16. In this embodiment, the expandable / contractible portion 18 penetrates the small diameter portion 16a of the fluid supply / discharge portion 16, and its interior communicates with the supply / discharge port 16b. The expandable / contractible portion 18 includes a fixed portion 18a that penetrates the small diameter portion 16a, and a bag-shaped portion 18b that expands and contracts with the supply and discharge of fluid. The fixed portion 18a of the expandable / contractible portion 18 is fixed to the outer circumference of the insertion portion 14.

[0048] The constituent material of the expandable / contractible portion 18 is preferably a material with excellent flexibility, for example, it is formed from a resin such as polyamide fiber. Furthermore, the surface of the expandable / contractible portion 18 is preferably slippery against the surface of the heat transfer tube 222, and it is preferable that it has high slipperiness, for example, it is preferably coated with Nitoflon® tape or a lubricant, or has a surface treatment that provides excellent slipperiness.

[0049] In the view of the flexible portion 10 in the direction of extension, the maximum diameter D of the expandable portion 18 when fluid is supplied and it expands is at least greater than the gap between adjacent heat transfer tubes 222 (see Figure 5, etc.). In this embodiment, the gap between adjacent heat transfer tubes 222 in the X and Y directions is 10 mm. In this case, the minimum diameter of the expandable portion 18 is preferably 9 mm or less, and the maximum diameter D is preferably 13.4 mm or more and 15 mm or less.

[0050] The support portion 20 shown in Figures 8 and 9 is inserted in the XZ direction from the inspection port 206 when the inspection device guide jig 1 accesses a predetermined inspection position inside the steam generator 200 of the embodiment, and is the part that performs positioning in the X direction. In other words, it is the part that determines which heat transfer tubes 222 adjacent to each other in the X direction the flexible portion 10 will protrude between. The support portion 20 is a rigid tubular shape, and is formed by curving the tubular tip so that it faces in a direction perpendicular to the axial direction of the base end. The flexible portion 10 is inserted through the support portion 20. The support portion 20 supports the base end of the flexible portion 10 so that the tip side of the flexible portion 10 can extend and retract from the tubular tip of the support portion 20. As shown in Figures 8 and 9, the support portion 20 has a rigid tube portion 22 and a direction changing portion 24.

[0051] The rigid tube section 22 is provided in a tubular shape that extends in a straight line. The rigid tube section 22 can house the flexible section 10 on its inner circumference. When the support section 20 of the rigid tube section 22 is inserted from the inspection port 206 of the steam generator 200 toward the opening 218a of the flow distribution plate 218 (see Figure 11, described later), the base end of the rigid tube section 22 is fixed by a fixing part (not shown) in a state that allows rotation only in the axial direction. In this embodiment, the rigid tube section 22 is a rectangular tube with a rectangular cross-section, but any cross-sectional shape is acceptable as long as the flexible section 10 can move in the axial direction inside. In this embodiment, the flexible section 10 is supported inside the rigid tube section 22 such that, for example, the direction in which the guide section 12, the fluid supply and discharge section 16, and the insertion section 14 are aligned is along the long side of the rectangle. The rigid tube section 22 is made of a metal with excellent corrosion resistance, such as SUS.

[0052] The orientation changing section 24 is provided in a substantially rectangular shape and fixed to the tip of the rigid tube section 22. The orientation changing section 24 is formed of a resin with excellent sliding properties, such as Teflon®. Inside the orientation changing section 24, there is a guide passage 26, one end of which communicates with an opening at the tip of the rigid tube section 22, and the other end which opens to one side surface 24a parallel to the axial direction of the rigid tube section 22. The cross-sectional shape of the guide passage 26 conforms to the cross-sectional shape of the rigid tube section 22, and in the embodiment, it is formed in a substantially rectangular shape. The guide passage 26 guides the flexible section 10 in the extending direction while curving it inside the orientation changing section 24. Between the disengagement hole 26a, which is an opening in the side surface 24a of the orientation changing section 24, and the connecting section 26b which communicates with the rigid tube section 22, the guide passage 26 includes a curved section 26c and an orientation guide section 26d.

[0053] The ejection hole 26a is the portion that the flexible portion 10 protrudes from its tip to the outside of the support portion 20. The direction in which the ejection hole 26a faces determines the direction in which the flexible portion 10 protrudes. The curved portion 26c is the portion that curves so as to bulge out on the opposite side of the side surface 24a relative to the connection portion 26b. The orientation guide portion 26d is located on the ejection hole 26a side of the curved portion 26c and guides the direction in which the flexible portion 10 protrudes toward the ejection hole 26a. With the guide path 26 formed in this way, the flexible portion 10 can be guided within the guide path 26 by smoothly curving from the axial direction of the rigid tube portion 22 to a direction perpendicular to the axial direction and protruding from the ejection hole 26a, thereby changing the orientation of its tip.

[0054] [Installation Procedure] Figure 10 is a flowchart showing the flow of the installation method for the inspection device guide jig according to the embodiment. Figures 11 to 16 are explanatory diagrams for illustrating the installation procedure shown in Figure 10. Note that the inspection device guide jig 1 is assumed to have a flexible part 10 inserted into the support part 20 in advance, with its tip 14a facing the dispensing hole 26a.

[0055] As shown in Figures 10 and 11, the worker first inserts the support part 20 through the inspection port 206 (step S1001). At this time, the worker inserts the support part 20 with the orientation changing part 24 side toward the opening 218a of the flow distribution plate 218 in the XZ direction. In the embodiment, as shown in Figure 5, in a plan view (view in the Z direction), there is a region in the X direction between the inspection ports 206 where no heat transfer tubes 222 are arranged. The support part 20 is inserted into the steam generator 200 by passing through this portion where the distance between the heat transfer tubes 222 in the Y direction is wide.

[0056] The worker inserts the support part 20 until the ejection hole 26a of the support part 20 reaches a predetermined X position. The predetermined X position is between adjacent heat transfer tubes 222 in the X direction and corresponds to the X position of the inspection position. When the ejection hole 26a of the support part 20 reaches the predetermined space between the heat transfer tubes 222 (step S1002), the worker fixes the base end of the support part 20 with a fixing part (not shown) on the outside of the inspection opening 206, for example, thereby fixing the insertion length and angle of the support part 20.

[0057] Next, as shown in Figures 10 and 12, the operator extends the flexible part 10 from the extension hole 26a of the support part 20 with the extension hole 26a facing diagonally upward in the YZ direction (step S1003). That is, the flexible part 10 is extended in the YZ direction relative to the support part 20. The flexible part 10 extends in the YZ direction with its base end supported by the support part 20. At this time, since the flexible part 10 bends due to its own weight, it is preferable to set the direction of extension according to the distance in the Y direction to the inspection position and the rigidity of the flexible part 10.

[0058] The operator extends the flexible part 10 until the expansion / contraction portion 18 of the flexible part 10 reaches a predetermined Y position. The predetermined Y position is between adjacent heat transfer tubes 222 in the Y direction and corresponds to the Y position of the inspection position. As shown in Figure 13, in a plan view (view in the Z direction), the support part 20 extends along the X direction, and the flexible part 10 extends along the Y direction. That is, the inspection device guide jig 1 is guided in the X direction by the support part 20 to perform positioning in the X direction, and guided in the Y direction by the flexible part 10 to perform positioning in the Y direction.

[0059] When the expandable / contractible portion 18 of the flexible portion 10 reaches a predetermined gap between the heat transfer tubes 222 (step S1004), the operator supplies fluid to the expandable / contractible portion 18 to expand it, as shown in Figures 10 and 14. At this time, the maximum width Dw of the expandable / contractible portion 18 in the X direction is greater than the gap Sx between adjacent heat transfer tubes 222 in the X direction, and the maximum width Dl of the expandable / contractible portion 18 in the Y direction is greater than the gap Sy between adjacent heat transfer tubes 222 in the Y direction. As a result, the expandable / contractible portion 18 is sandwiched between the heat transfer tubes 222 from all sides, making it physically impossible to move horizontally (XY direction), and thus it is positioned between the heat transfer tubes 222 (step S1005).

[0060] Next, as shown in Figures 10 and 15, the operator rotates the support part 20 around its axis so that the dispensing hole 26a of the support part 20 faces horizontally (Y direction). Because the XY position of the expandable / contractable part 18 on the tip end 14a side of the flexible part 10 is fixed, the flexible part 10 changes from a state in which it is bent downwards (as shown in Figure 12) to a state in which it is bent upwards (as shown in Figure 15) when viewed in the X direction. As a result, the flexible part 10 is in a position where the tip end 14a faces upwards.

[0061] Next, with the ejection hole 26a of the support section 20 oriented horizontally, the operator further extends the flexible section 10 from the ejection hole 26a (step S1006). As a result, the flexible section 10 is pushed upward and rises along the heat transfer tubes 222, as shown in Figure 16, because the expandable / contractable section 18 is supported between the heat transfer tubes 222 and cannot move horizontally (XY direction). When the tip 14a of the insertion section 14 of the flexible section 10 reaches the predetermined inspection position (step S1007), access to the predetermined inspection position is completed.

[0062] [Effects of the Embodiment] The inspection device guide jig and the method for installing the inspection device guide jig described in the embodiment can be understood, for example, as follows.

[0063] The inspection device guide jig 1 according to the first embodiment comprises a flexible rod-shaped guide portion 12, a curveable tubular insertion portion 14 along the extending direction of the guide portion 12 through which an inspection device is inserted, an expandable / contractable portion 18 provided on the outer circumference of the insertion portion 14 which expands when fluid is supplied to the inside and contracts when fluid is discharged from the inside, and a fluid supply / discharge portion 16 for supplying and discharging fluid to and from the expandable / contractable portion 18.

[0064] As a result, during internal inspection of the steam generator 200, by expanding the expandable / contractable part 18 at a position surrounded by the heat transfer tubes 222 directly below a predetermined inspection position, the expandable / contractable part 18 becomes physically unable to move horizontally, and the expandable / contractable part 18 can be positioned at that location. Since the expandable / contractable part 18 can only move vertically along the heat transfer tubes 222, it is possible to easily access the predetermined inspection position.

[0065] The inspection device guide jig 1 according to the second embodiment is the inspection device guide jig 1 according to the first embodiment, wherein the expandable / contractible portion 18 has a sliding surface.

[0066] This allows the expansion / contraction section 18 to easily reach a predetermined height as it rises along the heat transfer tube 222.

[0067] The inspection device guide jig 1 according to the third embodiment is the inspection device guide jig 1 according to the first or second embodiment, wherein the rigidity of the insertion portion 14 and the fluid supply / discharge portion 16 is lower than the rigidity of the guide portion 12.

[0068] As a result, when the guide portion 12, insertion portion 14, and fluid supply / discharge portion 16 bend together, the influence of rigidity from the insertion portion 14 and the fluid supply / discharge portion 16 is suppressed, improving handling.

[0069] The inspection device guide jig 1 according to the fourth embodiment is an inspection device guide jig 1 according to any one of the first to third embodiments, wherein the guide portion 12 is formed in a tubular shape and is provided to serve as both an insertion portion 14 and a fluid supply / discharge portion 16.

[0070] This allows the inspection device guide jig 1 to be made thinner overall, making it easy to move between the heat transfer tubes 222 and access directly below the predetermined inspection position.

[0071] The inspection device guide jig 1 according to the fifth embodiment is an inspection device guide jig 1 according to any one of the first to fourth embodiments, comprising a flexible portion 10 having a guide portion 12, an insertion portion 14, an expandable / contractable portion 18, and a fluid supply / discharge portion 16, and a non-deformable tubular support portion 20 through which the flexible portion 10 is inserted, and which is formed by curving its tip portion so that it faces in a direction perpendicular to the axial direction of its base portion.

[0072] As a result, the support portion 20 can move the flexible portion 10 in one horizontal direction (X direction), and the support portion 20 can support the flexible portion 10 when it is accessed in an intersecting direction (Y direction) perpendicular to the horizontal and one direction, thus making it easy to access inspection positions far from the inspection opening 206 of multiple heat transfer tubes 222 that are arranged in a row.

[0073] The inspection device guide jig 1 according to the sixth embodiment is the inspection device guide jig 1 according to the fifth embodiment, wherein the support portion 20 includes a tubular rigid tube portion 22 extending in a straight line, and an orientation changing portion 24 fixed to the tip of the rigid tube portion 22, having a guide path 26 inside that communicates with the rigid tube portion 22 and is curved to open (extraction hole 26a) on one side 24a parallel to the axial direction of the rigid tube portion 22.

[0074] This allows the straight rigid tube section 22 and the orientation changing section 24, which has a curved guide path 26, to be manufactured separately and then assembled, thus facilitating the manufacture of the support section 20.

[0075] A method for installing the inspection device guide jig 1 according to the seventh embodiment involves installing the inspection device guide jig, which comprises a flexible rod-shaped guide portion 12, a flexible tubular portion 14 that is bendable along the extending direction of the guide portion 12 and through which the inspection device is inserted, an expandable / contractable portion 18 provided on the outer circumference of the expansion / contractable portion 14 that expands when fluid is supplied to it and contracts when fluid is discharged from it, and a fluid supply / discharge portion 16 that supplies and discharges fluid to and from the expandable / contractable portion 18, and a non-deformable tubular support portion 20 through which the flexible portion 10 is inserted, with the tip portion curved so that it faces in a direction perpendicular to the axial direction of the base portion, by inserting the inspection device guide jig through a plurality of heat transfer tubes 222 that extend in the Z direction and are arranged side by side in the X and Y directions inside the steam generator 200. A method for installing an inspection device guide jig 1 to be installed at a predetermined inspection position for inspecting a pipe support plate 216, comprising: an insertion step of inserting a support portion 20 in the XZ direction from an inspection port 206 of a steam generator 200; an X-direction positioning step of orienting the tip 14a of the flexible portion 10 in the YZ direction from between adjacent heat transfer tubes 222 in the X direction at a position in the X direction corresponding to the inspection position; an extension step of extending the flexible portion 10 from the support portion 20 in the YZ direction; a Y-direction positioning step of supplying fluid to the expand / contract portion 18 to expand it and positioning it between adjacent heat transfer tubes 222 in the Y direction at a position in the Y direction corresponding to the inspection position; and an installation step of further extending the flexible portion 10 from the support portion 20 so that the tip 14a of the insertion portion 14 reaches the inspection position.

[0076] As a result, during the internal inspection of the steam generator 200, the support part 20 carries the flexible part 10 to the X position corresponding to the X position of the predetermined inspection position, and then moves the flexible part 10, with its base end supported by the support part 20, to the Y position corresponding to the Y direction of the inspection position, i.e., the position surrounded by the heat transfer tubes 222 directly below the inspection position. Then, by expanding the expandable / contractible part 18, the expandable / contractible part 18 can be made physically immobile in the horizontal direction, so the expandable / contractible part 18 can be positioned at that location. Since the expandable / contractible part 18 can only move vertically along the heat transfer tubes 222, it can be easily accessed to the predetermined inspection position.

[0077] The installation method for the inspection device guide jig 1 according to the eighth aspect is the installation method for the inspection device guide jig 1 according to the seventh aspect, wherein in the unwinding step, the flexible part 10 is extended diagonally upward, and in the installation step, the flexible part 10 is extended horizontally.

[0078] As a result, when extending the flexible part 10 in the Y direction, it is possible to access a greater distance, and when extending the flexible part 10 in the Z direction, the tip portion 14a of the flexible part 10 can be directed upward, making it easy to move it upward in the Z direction.

[0079] Although embodiments of this disclosure have been described above, the embodiments are not limited to those described herein.

[0080] For example, in the embodiment, the flexible portion 10 is provided with a guide portion 12, a fluid supply and discharge portion 16, and an insertion portion 14 arranged in parallel and in a single line, forming a flat tube overall. However, for example, the fluid supply and discharge portion 16 may be provided so as to cover the outer circumference of the insertion portion 14, which is also used as the guide portion 12. In this case, the expandable and contractible portion 18 may be provided so as to cover the outer circumference of the fluid supply and discharge portion 16, and may expand and contract radially in all directions when viewed in the direction of extension. [Explanation of symbols]

[0081] 1. Inspection device guide jig 10 Flexible part 12 Information Department 14 Insertion part 16 Fluid supply / discharge section 18. Expanding and contracting section 20 Support part 22 Hard tube section 24 Directional change section 26 Guide Route 100 Nuclear power plants 200 Steam Generator 206 Inspection hatch 216 Pipe support plate 218 Flow distribution plate 218a aperture 220 heat transfer tube group 222 Heat transfer tubes

Claims

1. A flexible rod-shaped guide section, The guide portion has a flexible tubular shape along its extending direction, through which an inspection device is inserted, An expandable / contractable portion is provided on the outer circumference of the insertion portion, which expands when fluid is supplied to the inside and contracts when fluid is discharged from the inside, A fluid supply and discharge section for supplying and discharging fluid into the expansion and contraction section, Equipped with, Inspection equipment guide jig.

2. The aforementioned expanding and contracting portion has a surface that is slippery, The inspection apparatus guide jig according to claim 1.

3. The insertion portion and the fluid supply / discharge portion have lower rigidity than the guide portion. The inspection apparatus guide jig according to claim 1.

4. The guide portion is formed in a tubular shape and is provided to serve in conjunction with the insertion portion or fluid supply / discharge portion. The inspection apparatus guide jig according to claim 1.

5. A flexible portion having the guide portion, the insertion portion, the expansion and contraction portion, and the fluid supply and discharge portion, A support portion which is a non-deformable tubular shape through which the flexible portion is inserted, and which is formed by curving the tip portion so as to face in a direction perpendicular to the axial direction of the base portion, Equipped with, The inspection apparatus guide jig according to claim 1.

6. The aforementioned support portion is A tubular rigid section extending in a straight line, A direction-changing section is fixed to the tip of the rigid tube section, has a guide path inside that communicates with the rigid tube section and is curved, opening on one side parallel to the axial direction of the rigid tube section, Having, The inspection apparatus guide jig according to claim 5.

7. A flexible rod-shaped guide section, The guide portion has a flexible tubular shape along its extending direction, through which an inspection device is inserted, An expandable / contractable portion is provided on the outer circumference of the insertion portion, which expands when fluid is supplied to the inside and contracts when fluid is discharged from the inside, A fluid supply and discharge section for supplying and discharging fluid into the expansion and contraction section, A flexible part having, A support portion which is a non-deformable tubular shape through which the flexible portion is inserted, and which is formed by curving the tip portion so as to face in a direction perpendicular to the axial direction of the base portion, An inspection device guide jig equipped with A method for installing an inspection device guide jig to be placed at a predetermined inspection position in order to inspect a tube support plate that supports multiple heat transfer tubes that extend in the Z direction and are arranged side by side in the X and Y directions inside a steam generator, An insertion step of inserting the support portion in the XZ direction from the inspection port of the steam generator, An X-direction positioning step is performed to orient the tip of the flexible portion in the YZ direction from between adjacent heat transfer tubes in the X direction at a position in the X direction corresponding to the inspection position, An extension step in which the flexible portion is extended from the support portion in the YZ direction, A Y-direction positioning step involves supplying fluid to the expansion / contraction section to expand it at a position in the Y-direction corresponding to the inspection position, and positioning it between adjacent heat transfer tubes in the Y-direction. Installation step: Further extending the flexible portion from the support portion to bring the tip of the insertion portion to the inspection position, including, Method for installing the inspection equipment guide jig.

8. In the aforementioned deployment step, the flexible portion is extended diagonally upward, In the installation step, the flexible portion is extended horizontally. A method for installing the inspection device guide jig according to claim 7.

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