CN100567814C - Steam generator sludge flushing system with flexible belt type spray gun - Google Patents

Abstract

The invention discloses a kind of steam generator sludge rinse-system that has flexible banding pattern spray gun, it can wash away the sludge in the steam generator that is deposited in heavy water reactor nuclear power plant and can remove impurity from the upper plate of tube sheet by high-pressure spray.According to the present invention, steam generator sludge rinse-system comprises: the driver support lugn and the rail-guided device support lugn that are attached to the hand hole of steam generator; Rail-guided device, it is installed in the elongated rectangular space that is limited to the steam generator middle part by the driver support lugn; The T shape rail that can reverse, its groove by rail-guided device are installed and are had a barrel formula spray nozzle; Flexible banding pattern spray gun, it is inserted in the T shape rail and under the guiding of the crooked guiding mechanism that is installed to T shape rail end crooked 90 °; And lance head, it is installed to the end of flexible banding pattern spray gun and comprises the nozzle end with different spray angles.

Description

Steam generator sludge flushing system with flexible belt type spray gun

technical field

The invention relates to a steam generator sludge flushing system with a flexible belt type spray gun. More specifically, the present invention relates to a steam generator sludge flushing system with a flexible belt-type spray gun capable of removing sludge deposited in a steam generator of a heavy water reactor nuclear power plant by high-pressure jet flow and also capable of removing sludge from the tube sheet The upper plate removes impurities.

Background technique

In general, a steam generator is an essential structure of a nuclear power plant, where heat exchange between primary coolant heated by a nuclear reactor and secondary coolant installed at the boundaries of tubes in the steam generator is performed.

Kinetic energy is converted into electricity when the steam generated by the heat exchange drives a turbine. Power generation is thus achieved. However, as the operating time of the nuclear power plant increases, the tubes of the secondary circuit system will be worn out. Metal particles falling from the pipes collect in the steam generator in the form of sludge. Also, material falling from the structure can flow into and remain in the steam generators during the plant's planned maintenance and repairs.

The sludge occurring in the steam generator can be divided into soft sludge and hard sludge. Soft sludge generally accumulates on the upper layer of the steam generator and hard sludge accumulates on the tube sheet arranged on the lower layer of the steam generator. Hard sludge is formed when the sludge on the tube sheet is hardened by the high temperature of the tube.

The accumulated sludge reduces the heat transfer performance of the tubes of the steam generator, further reducing the heat output efficiency which ultimately determines the output of the nuclear power plant. In some overseas nuclear power plants, accumulation of sludge that reduces power plant output has been reported as a reason for power plant shutdown. In addition, since the sludge causes partial corrosion of the steam generator, frequent replacement of the steam generator is required. This will result in considerable economic losses.

Furthermore, impurities present on the casing of the steam generator tubes can be carried over in the circulation flow of the system water and can damage structures within the steam generator by colliding with them. Therefore, in general, nuclear power plants undergo periodic planned maintenance to remove sludge and other impurities.

Methods used to remove sludge from steam generators include high-pressure jet cleaning, chemical cleaning, ultrasonic cleaning, and hybrid cleaning. Although chemical cleaning is most effective, it can corrode the tubes. Therefore, only 2-3 chemical cleanings can be performed during the lifetime of the steam generator.

Due to the potential of ultrasonic cleaning, research and development of ultrasonic cleaning is currently being intensively carried out, but its cleaning efficiency has not been accurately evaluated. High pressure jets are the most practical and beneficial in the absence of any safe alternatives to date.

A variety of special tools including pliers, tripods, collectors, and magnets can be used to remove sludge. For higher removal efficiency, these tools need to be cleaned with high pressure jets.

According to the traditional "Sludge lancing system of a nuclear steam generator" (application number KR 10-2004-0090110), the sludge between the pipes is approached by a belt-type flexible spray gun. However, the band nut connection system suffers from the drawback of sagging. In addition, since the spray gun drive motor installed in the steam generator is exposed to high radiation energy, the exposure of the spray gun drive motor to the radiation energy often leads to the shutdown of the entire system.

Contents of the invention

Therefore, the present invention has been made in consideration of the above-mentioned problems, and an object of the present invention is to provide a steam generator sludge flushing system with a flexible belt type spray gun, which can more efficiently pass through the narrow gap between the pipes smoothly. Effectively and conveniently removes accumulated sludge and impurities from steam generator tube sheets.

Another object of the present invention is to provide a steam generator sludge flushing system with a flexible belt-type spray gun, which is equipped with tools for the operator to find, access and remove sludge and impurities more easily, and which has monitoring function to easily check the results of sludge removal.

According to the present invention, the above and other objects can be achieved by providing a steam generator sludge flushing system comprising: a driver support flange attached to a hand hole of the steam generator and rail guide support flange; rail guide, which is installed in the elongated rectangular space defined in the middle of the steam generator by said driver support flange; twistable T-shaped rail, which passes through said rail guide slot mounted and has a barrel spray nozzle; a flexible strip spray gun that is inserted into the T-rail and bent 90° under the guidance of a curved guide mounted to the end of the T-rail; and a spray gun head that Mounts to the end of the flexible ribbon spray gun and includes nozzle ends with different spray angles.

Description of drawings

According to the following detailed description in conjunction with the accompanying drawings, the above and other objects, features and other advantages of the present invention will be more clearly understood, wherein:

1 is a perspective view showing a steam generator sludge flushing system with a flexible belt type spray gun when installed to a steam generator according to a first embodiment of the present invention;

Figure 2 shows the flow of secondary coolant in the steam generator of a heavy water reactor and also shows the lower part of the steam generator enlarged;

Figure 3 is a perspective view showing the steam generator sludge flushing system as a whole;

Figure 4 is a perspective view of the driver of the steam generator sludge flushing system;

Fig. 5 is a perspective view of the track guide device of the sludge flushing system of the steam generator;

Fig. 6 is a perspective view of the tension regulator of the track guide device of the sludge flushing system of the steam generator;

Figure 7 is a perspective view of a T-rail of the steam generator sludge flushing system;

Fig. 8 is a perspective view of the tension adjuster of the T-rail of the steam generator sludge flushing system;

Figure 9 shows the structure for barrel spray operation in a steam generator sludge flushing system, also showing the system's flexible belt spray gun in greater detail in an enlarged perspective view; and

10 is a perspective view of a bending guide for guiding bending of a flexible belt-type spray gun in a steam generator sludge washing system according to an embodiment of the present invention.

Detailed ways

A steam generator sludge washing system with a flexible belt type spray gun according to an exemplary embodiment of the present invention and its operation will be described in detail below with reference to the accompanying drawings.

The steam generator sludge flushing system 300, which is a steam generator sludge flushing system 300 of the type including a flexible belt-type spray gun, includes a track guide 500 installed in the steam generator 200, particularly installed in the steam generator A ductless passage area in the form of an elongated rectangular space is formed in the middle of the device 200 . The rail guide 500 has a T-shaped slot 503 . The steam generator 200 includes relatively small hand holes 201 and 202 facing each other. The steam generator sludge flushing system 300 also includes a T-shaped rail 700 that includes a protrusion 702 having a T-shaped cross-section and performs barrel spraying operation, and a flexible belt-type spray gun 900 . The flexible belt-type spray gun 900 includes: an endoscope camera 901; an air supply line 902; an impurity removal tool 903; nozzle ends 904, 905, 906, and 907 for spraying high-pressure water; High pressure hose 909. The steam generator sludge washing system 300 also includes a driver supporting flange 301 and a rail guide supporting flange 302 installed to the hand holes 201 and 202 to rotatably support the steam generator sludge washing system 300 , respectively.

The driver support flange 301 is mounted to the hand hole 201 inserted into the steam generator sludge flushing system 300 through a total of six stud holes 419, two of which are positioned along a horizontal line and the other two are positioned high. approximately 50° from horizontal, and the remaining two are positioned approximately 50° below horizontal. The track guide tensioner 501 , which helps the track guide 500 to twist and has a gear 603 , is connected to the bearing bracket 406 of the drive support flange 301 . Therefore, the rail guide 500, the T-rail 700, and the flexible belt-type spray gun 900 can smoothly realize the twisting.

The track guide support flange 302 is securely mounted to the hand hole 202 by six studs (not shown) and six stud holes 306 . Also, the track guide support flange 302 includes a bearing frame 308 that rotatably supports the end coupler 304 of the track guide 500 .

A rail guide tension adjuster 501 bolted to the rail guide 500 transmits a rotational force from the first servo motor 402 to the rail guide 500 and also has a cable tensioner lever 601 that tensions the tension cable 504 .

The rail guide 500 is in the shape of a rod having a semicircular cross-section while including a T-shaped slot 503 . The track guide 500 consists of three segments 502 . The track guide 500 may consist of more than three segments, if necessary. Since each segment 502 has an assembly pin 505 at its end, the T-slots 503 can remain aligned. When the tensioner rod 601 tensions the tension cable 504, the section 502 can be firmly joined as a unitary rod.

In the same style as track guide 500, T-rail 700 including protrusion 702 includes assembly pin 705, tension cable 704, and tensioner rod 801 so that segment 701 of T-rail 700 can be secured as a unitary rod combined. In addition, since the rack 703 is formed on the protrusion 702 , the T-shaped rail 700 can slide forward and backward along the T-shaped groove 503 of the rail guide 500 . The T-rail 700 also includes a rectangular hole 311 therein through which the flexible belt spray gun 900 can extend. A plurality of bucket spray nozzles 908 are arranged on the T-rail 700 to spray a large amount of high-pressure water supplied from the high-pressure hose 407 .

The flexible ribbon spray gun 900 is constructed by laminating and processing layers of polyurethane so that vertical bending is limited and lateral bending is flexible. The flexible belt-type spray gun 900 includes: a high-pressure hose 900 particularly having a slender diameter; nozzle ends 904, 905, 906, and 907; an endoscope camera 901 for inspecting the inside of the steam generator 200; 901, an air supply line 902 for obtaining clear images from impurities in the lens; and an impurity removal tool 903 for removing detected impurities.

Figure 2 shows the flow of the secondary coolant in the steam generator, and also shows enlarged the upper part of the tube sheet mounted to the lower part of the steam generator, where the flow of the coolant is relatively slow. Metal sludge contained in the secondary coolant generally accumulates in the upper portion of the tube sheet. Therefore, a steam generator sludge flushing system 300 is installed at this location to remove metal sludge.

Figure 1 shows a steam generator sludge flushing system mounted to a tubeless passage area formed on a tube sheet provided in the lower part of the steam generator.

Referring to FIGS. 1 to 4 , in order to install the steam generator sludge flushing system 300 , first, the track guide supporting flange 302 engaged with the bearing frame 308 is fastened to the hand of the steam generator 200 through studs and through holes 306 . Hole 202. A first servo motor 402 including an encoder 401 acquiring twist information, a gear head 403 increasing motor torque, and a gear 404 transmitting torque is fixed to the driver supporting flange 301 by bolts. The driver support flange 301 is fastened to the hand hole 201 of the steam generator 200 by stud bolts.

As shown in FIG. 3 , the end coupler 304 for the track guide 500 is connected to the last section 502 of the track guide 500 and the track guide tensioner 501 is connected to the first section 502 . All segments 502 of track guide 500 are aligned with assembly pins 505 and corresponding pin holes. Next, the tension cable 504 is tensioned by the tensioner rod 601 such that the segments 502 of the track guide 500 are firmly joined in the form of a unitary rod. Furthermore, the track guide support flange 302 is fastened to the end coupler 304 of the track guide 500 which fits into the driver support flange 301 . The bearing bracket 406 of the drive support flange 301 is fastened to the track guide tension adjuster 501 . Therefore, the torsion can be smoothly achieved by the bearing.

4, when the second servo motor 417 including the encoder 418 and the gear head 416 is mounted to the rack motor housing 415, the rack motor housing 415 is fastened to the rail guide tension adjuster 501 through the screw hole 602 so that It rotates with the track guide 500 .

A curved guide 1000 ( FIG. 10 ) is fastened to the last segment 701 of the T-rail 700 through bolt holes 1001 . A T-rail tension adjuster 803 mounted with a tensioner rod 801 is secured to the last section 701 of the T-rail 700 through bolt holes 804 . All segments 701 of T-rail 700 are aligned with assembly pins 705 and firmly joined as a unitary bar by tensioning tension cables 704 through tensioner bar 801 .

After the T-rail 700 is assembled, a pair of third servo motors 412 each including an encoder 410 , a gear head 413 and a roller 414 are mounted to the roller motor housing 409 . The roller motor housing 409 is secured to the T-rail tensioner 803 by screw holes 802 so that the roller 414 rotates with the roller motor housing 409 when the T-rail 700 rotates.

As shown in FIG. 9 , the flexible belt-type spray gun 900 is inserted into the rectangular hole 311 of the T-rail 700 until the spray gun head 910 is exposed. Here, the distance between the axes of the rollers 414 needs to be properly adjusted. Accordingly, the roller motor housing 409 includes threaded holes designed with tolerances to properly adjust the distance between the motor shafts. The flexible ribbon spray gun 900 is inserted after the distance adjustment.

The T-shaped rail 700 inserted into the flexible belt-type spray gun 900 is inserted into the hand hole 201 of the steam generator 200 such that the protrusion 702 having a T-shaped cross-section fits into the T-shaped groove 503 of the rail guide 500 . Next, the rack gear 709 of the T-rail 700 meshes with the spur gear 303 fixed to the shaft of the second servo motor 417 so that the T-rail 700 can linearly move back and forth along the T-slot 503 of the rail guide 500 .

The operation of the steam generator sludge flushing system 300 will now be described in more detail.

In the steam generator 200 installed with the driver supporting flange 301, it is assumed that the first row refers to the row of the tubes arranged farthest from the hand hole 201, if the last of the six barrel spray nozzles 908 of the T-shaped rail 700 One is arranged between the first row and the second row, and the barrel spray nozzles 908 are arranged between the tube rows in the following manner: each barrel spray nozzle 908 is arranged between adjacent rows.

A large amount of high pressure water is supplied and sprayed through barrel spray nozzles 908 . Here, the bucket spray nozzle 908 is tilted using the first servo motor 402 . Metal sludge is flushed from the annular space inside the steam generator 200 . After performing this step at least three times, the T-rail 700 is turned 180° by the first servo motor 402 to flush out the sludge on the opposite side of the pipe.

When the barrel spraying operation between the first and second columns is completed, the second servo motor 417 is driven. The barrel spray operation was repeated after displacing the T-rail 700 a distance of three columns. In this way, the bucket spray operation is completed by moving the T-rail 700 in three rows until the last row.

Since the above-described process can be performed by simple repetition, only operator supervision is required to automate the process. Of course, the operator can perform this process manually.

After the barrel spraying operation is completed, the spray gun head 910 of the flexible belt spray gun 900 of FIG. 9 is moved back to the middle of the first row and the second row. The sludge is removed from the pipe by applying high pressure jets between the first and second columns from the spray gun head 910 with obliquely directed nozzle ends 904 and forwardly directed nozzle ends 905 .

The parallel mounted rollers 414 are then driven by a third servo motor 412 . The flexible belt spray gun 900 is propelled into the T-rail 700 using the friction of the rollers 414 . Then, the flexible belt-type spray gun 900 is introduced into the gap between the tubes while being bent under the guidance of the spray gun path 1002 of the curved guide 1000 installed at the end of the T-shaped rail 700, so that the spray gun head 910 can enter into the first row and between the second column.

More specifically, high pressure jets are generated through nozzle ends 904, 905, 906, and 907 mounted to the spray gun head 910 before the spray gun head 910 enters between the first and second columns. Spray gun head 910 is prevented from getting stuck by the tube by prior removal of sludge that accumulates on the tube.

In particular, the forward-pointing nozzle end 905 removes sludge from the sides of the tube between columns, the obliquely-pointing nozzle end 904 removes sludge on the tube slope, and the upwardly and downwardly-pointing nozzle ends 906 remove The sludge accumulated on the tube sheet of the steam generator 200 is removed.

When flushing of all tubes is complete, the spray gun head 910 moves back between the first and second columns to inspect and remove impurities.

An endoscope camera 901 mounted to the gun head 910 is used to inspect the tube. The air supply pipe 902 blows away the moisture on the lens of the endoscope camera 901 to ensure the reliability of the lens. Therefore, the endoscope camera 901 performs inspection with a guaranteed clear field of view.

When any impurity is detected, the location and type of the impurity is checked and a suitable impurity removal tool 903 is applied accordingly to remove the impurity. Typically, various tools including pliers, tripods, collectors, and magnets can be used instead. When the impurity removal tool 903 has difficulty removing the impurity, the impurity can be flushed away from the annular space of the pipe by applying a high pressure jet towards the forwardly directed nozzle end 905 . The above process is repeated through all tube columns.

As mentioned above, the steam generator sludge flushing system with flexible belt type spray gun according to the present invention can be installed through the hand hole of the steam generator less than 63 mm, and can be installed by putting the flexible belt type spray gun into the steam generator The gap between the pipes is less than 5mm and the high-pressure water is sprayed to the sludge to effectively remove the sludge. In addition, the steam generator sludge flushing system is able to remove impurities between the tubes using a variety of special tools mounted to the spray gun head.

Since, according to the present invention, the servo motors supplying the driving force are provided outside the steam generator, it is possible to reduce malfunctions compared to the conventional technique in which the servo motors are installed in the steam generator and exposed to high radiation energy.

Furthermore, according to the invention, the different angles of the nozzle ends for the high-pressure jets enable the jets to emerge in oblique directions. Since the sludge is removed by the high-pressure jet before the flexible belt gun is moved between the tubes, it is possible to prevent the flexible belt gun from getting stuck between the tubes. Also, the side-directed nozzle ends enable removal of sludge on the rear side of the pipe, where conventional techniques cannot. Upward and downward facing nozzle ends remove sludge that collects on the tubesheet. Therefore, the flushing efficiency is greatly improved.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and and substitute.

Claims (12)

1. A steam generator sludge flushing system, comprising: the driver support flange and the track guide support flange attached to the hand hole of the steam generator; a rail guide mounted within an elongated rectangular space defined in the middle of said steam generator by said driver support flange; Twistable T-rails fitted through slots in said rail guides and having bucket spray nozzles; a flexible belt-type spray gun inserted into said T-rail and bent through 90° under the guidance of a bending guide mounted to the end of said T-rail; and A spray gun head mounted to the end of the flexible belt-type spray gun and including nozzle ends having different spray angles. 2. The steam generator sludge flushing system according to claim 1, wherein said track guide support flange is attached to one of said hand holes on the opposite side where said track guide is inserted to support The end coupler of the track guide, and the track guide support flange includes a bearing bracket that facilitates smooth twisting of the track guide. 3. The steam generator sludge flushing system of claim 1, wherein said driver support flange is attached to one of said hand holes on the side where said track guide is inserted, further comprising: a first servo motor supplying driving force for twisting of the track guide; and A bearing bracket mounted to the drive support flange to rotatably support the track guide tension adjuster. 4. The steam generator sludge flushing system according to claim 3, wherein said rail guide is twistable and consists of at least three sections having T-shaped slots and being connectable to each other with assembly pins, and said rail The guides include tension cables and rail guide tension adjusters so that the segments can be firmly joined in the form of integral rods and the T-rails can linearly reciprocate in the steam generator. 5. The steam generator sludge flushing system of claim 4 wherein said track guide tension adjuster is attached to the last section of said T-rail and comprises: a gear for transmitting the driving force of the first servo motor; a groove formed along the movement path of the tension cable to prevent the tension cable from obstructing other components; and A tensioner rod connected to the tension cable for stably maintaining the overall state of the rail guide by tensioning the tension cable. 6. The steam generator sludge flushing system according to claim 5, wherein the T-rail is composed of three or more sections so that it can be integrally integrated with assembly pins, tension cables and T-rail tension adjusters. Rod form is firmly attached and includes: T-shaped protrusion; a rack formed on the upper surface of the T-shaped protrusion to receive a driving force from a second servo motor installed in the rack motor housing through a spur gear and thus make the T-shaped rail along the T-shaped groove reciprocate linearly; a slot formed in the T-rail and having a rectangular cross-section, the slot allowing the flexible belt-type spray gun to perform according to the driving force transmitted to the flexible belt-type spray gun through the roller of the third servo motor mounted to the roller motor housing reciprocating motion; A bending guide formed in the first section of the T-shaped rail to guide the bending of the flexible belt-type spray gun through 90°. 7. The steam generator sludge flushing system of claim 6, wherein said T-rail tension adjuster is attached to the last section of said T-rail and comprises: a groove formed along the movement path of the tension cable to prevent the tension cable from obstructing other components; and A tensioner rod connected to the tension cable for stably maintaining the overall state of the rail guide by tensioning the tension cable. 8. The steam generator sludge flushing system according to claim 7, wherein said curved guide is mounted to the last section of said T-rail through bolt holes to guide a flexible The belt gun is bent at 90° and the curved guide has a larger size than the rectangular section slot of the T-rail used as the path of the flexible belt gun to prevent the gun head from jamming. 9. The steam generator sludge flushing system of claim 8, wherein the second servo motor is mounted to the rack motor housing and includes an encoder, a gear head, and a shaft mounted to the second servo motor and connected to The gear rack of the T-shaped track engages the spur gear to convert the linear motion into the rotational motion, and the rack motor housing is fastened to the rail guide tension adjuster by bolts according to the torsion of the rail guide is twisted to maintain the mesh between the spur gear and the rack. 10. The steam generator sludge flushing system of claim 9, wherein the roller motor housing has capacity for two servo motors each having an encoder and a gear head, the roller motor housing comprising A bolt hole for fixing the servo motor, the bolt hole has a tolerance for adjusting the distance between the two rollers fixed to the two servo motor shafts respectively, and the roller motor housing is fixed to the T-rail tension adjuster to twist with the T-rail. 11. The steam generator sludge flushing system according to claim 10, wherein said flexible belt type spray gun is constructed by laminating and processing polyurethane layers so that vertical bending is limited but lateral bending is flexible, so that through said The curved guide of the T-rail can be easily bent, and the flexible belt-type spray gun includes a foreign matter removal tool with a thin high-pressure hose, an air supply line, an endoscope cable and a cable. 12. The steam generator sludge flushing system of claim 11, wherein the spray gun head comprises: an endoscopic camera to check for impurities in the steam generator; an air supply line inserted into the flexible belt-type spray gun and adapted to remove impurities from the lens of the endoscopic camera to ensure a clear view of the camera; a nozzle end connected to said high pressure hose to spray high pressure water; and Common tools for removing impurities, The nozzle ends include: angled nozzle ends to clean the entry path of the spray gun head; upward and downward facing nozzle ends to remove sludge accumulated on the tube sheet of the steam generator; side Towards the nozzle end, to remove sludge that collects on the rear side of the pipe; and the forward-facing nozzle end, to remove sludge that collects on the side of the pipe; and a general tool for removing impurities.

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