JP2915318B2 - Automatic sludge lance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates generally to cleaning equipment for steam generators and, more particularly, to an automatic sludge lance and method for cleaning sludge from a steam generator tube of a steam generator.

[0002]

2. Description of the Related Art In a nuclear power plant, a steam generator such as a recirculating steam generator or a once-through steam generator is used for the purpose of exchanging heat when generating steam for driving a turbine. Primary coolant heated in the core passes through the tube bundle of the steam generator. A secondary coolant, usually water, is introduced into the space surrounding the tube bundles, receives the heat from these tube bundles, is converted to steam, and drives the turbine. After cooling and condensing, the secondary coolant returns to the space around the tube bundle, providing a continuous cycle of steam generation. Due to the constantly high temperature and severe operating conditions, sludge accumulates on the lower part of the tube bundle and on the tube sheets supporting these tube bundles. Sludge consists mainly of iron oxides, for example magnetite, which reduces the heat transfer efficiency of the tube bundle and can also cause corrosion. Thus, it is necessary to periodically clean the tube bundle to remove sludge. Cleaning of the tube bundle can be performed by various types of devices and methods. U.S. Pat. No. 4,556,406, entitled "Sludge Removal Apparatus for Steam Generators", discloses a method of rigidly attaching to a tube sheet and holding it in place during conventional steam operation on the top of the tube sheet. Are described. An opening is provided in the wall surface of the steam generator, and the slurry is removed from the opening. U.S. Pat. No. 4,079,701 entitled "Steam Generator Sludge Removal System" provides a plurality of headers at the height of the sludge to be removed from the periphery of the tube bundle, at which point a circumferential header is provided. An arrangement for establishing fluid flow is described. A fluid lance moving along a movement line between the plurality of headers emits a fluid jet in a direction orthogonal to the movement line of the fluid lance. The fluid lance can also be swiveled upon removal. US Patent No. 4,7, entitled "Sludge Lance Bar"
No. 00,662 describes a lance for cleaning the tube bundle of a once-through steam generator. Since the lance has a constant radius of curvature, it must be manually steered and inserted between the tubes inside the tube bundle of the steam generator. US Patent No. 4,9 entitled "Articulated Sludge Lance"
No. 80,120 describes an articulated lance for cleaning sludge between the tubes of a steam generator tube bundle. This lance is inserted into a lane or space between each tube of the tube bundle through a handhole during operation. U.S. Pat. No. 5,194,217, entitled "Articulated Sludge Lance With Movable Extension Nozzle" describes an articulated sludge lance with a retractable movable extension nozzle. No. 4,980,12.
No. 0, in its description of the prior art, US Pat.
56,406, 4,079,701, 4,700,
Various techniques found in each of 662 are described. And U.S. Pat. No. 4,407,236 describes a thin strip of spring steel entering a tube lane for sludge lance cleaning for a nuclear steam generator. The forward end of the capillary is directed downward to eject fluid under high pressure. U.S. Pat. No. 4,827,953 relates to an automatic flexible lance for removing sludge on the secondary side of a steam generator. Here, a flexible lance is described that includes a plurality of flexible hollow tubes that extend along the length of the flexible member and that can be remotely steered within the steam generator. A plurality of nozzles are provided at an end of the flexible member, and the flexible member is shaped so as to enter a difficult-to-access dimension portion of the steam generator. U.S. Pat. No. 5,065,703 describes an improved flexible automatic lance for a steam generator. U.S. patent application Ser. No. 08 / 126,453, filed Sep. 24, 1993, describes an articulated annular sludge lance. Thus, a remotely controlled automatic sludge lance steering method and apparatus, wherein the sludge lance is positioned and steered within the steam generator, and yet the drive assembly is positioned outside the steam generator for ease of access. There is a demand for Positioning outside the steam generator facilitates maintenance of the drive assembly and eliminates concerns about harsh environmental and space constraints. Also, the detached parts do not stop inside and damage the steam generator. The method and apparatus should operate from the tube generator lane-free and / or annular chamber sections to provide the largest possible clean area.

[0003]

SUMMARY OF THE INVENTION The drive assembly is
The drive assembly is positioned outside the air generator.
Easy access to the bridge and the drive assembly
Maintenance inspections have been simplified to meet severe environmental and space constraints.
The worries are eliminated and the detached parts stay inside
It is an object of the present invention to provide an automatic sludge lance for cleaning a tube bundle inside a steam generator without damaging the steam generator.

[0004]

According to the present invention, not only the problems related to the prior art as described above, but also other problems,
Method for cleaning a steam generator and automatic sludge lance therefor (hereinafter simply referred to as sludge lance)
Is provided. In accordance with the method of the present invention, sludge between a plurality of tubes inside a steam generator is removed by remotely maneuvering and positioning a lance guide and a water lance. In this case, the drive assembly for the lance guide and the water lance is located outside the steam generator and is attached to the mounting flange of the steam generator. The cleaning operation is performed by positioning the lance guide at a preselected position in the steam generator and advancing a water lance held by the lance guide in a movable state between the pipes. A sludge lance according to the present invention removes sludge from between each tube of a tube bundle inside a steam generator by manipulating a lance guide from outside the steam generator using a sludge lance drive assembly. The lance guide holds the water lance, and the water lance moves with the lance guide, and comes out of the lance guide to clean the space between the tubes.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, an automatic sludge lance according to the present invention is generally designated by the numeral (10). The automatic sludge lance (10) is attached to the part (4) of the steam generator (2) without the pipe lane via the handhole (6), which in this embodiment is an inspection port, of the mounting bracket (8). . This automatic sludge lance (1
Reference numeral 0) denotes a lance guide (12), a water lance (14) held movably in the lance guide, and a lance guide (12) and a water lance (14).
And a sludge lance drive assembly (22) for driving the drive. The lance guide (12) and the water lance (14) are connected to the steam generator tube lane-free part (4).
And placed at a selected location between the tubes (3).
A proximity sensor (35) associated with the lance guide head (34) first identifies the position of the tubes and then determines the lane between the tubes. At this point, the water lance (14) is advanced into the tube lane between the tubes (3) and a fluid such as water is injected at high pressure to remove sludge from between the tubes (3). Similar embodiments for removing sludge are described in U.S. Patent Nos. 4,980,120 and 5,194,127. "Water lance" means lance (14)
And any fluid delivered at a high pressure.

The lance guide (12) basically has a somewhat U shape.
A groove in the shape type, has a structure to receive the water lance (14). The lance guide may be formed of metal or plastic, such as aluminum, for example, Delrin or polypropylene. The water lance (14) comprises a front and a rear manifold made of stainless steel, at least one, preferably a plurality of pressure tubes of the fiber winding type, and a single, fiber reinforced casting polymer, for example polyurethane. It is preferred to include a matrix body made of: Water Lance (14)
Nos. 4,980,120 and 5,19.
The fluid dispensing member described in U.S. Pat. A row of holes (16) are provided along the center line of the lance guide (12) and the water lance (14), and the orbiting type sludge lance drive assembly (22) is remotely operated in these holes (16). Is engaged. In a preferred embodiment, the sludge lance drive assembly (22) includes a pinned belt (18) driven by a pulley (20). This belt with pin (1
Preferably, 8) is a flexible metal belt and the pulley (20) is a grooved stainless steel wheel.

According to this arrangement, a high traction force is generated by the simultaneous engagement of the pins of the belt with pins (18) with several holes (16). Since the maximum design number of pressure tubes can still be incorporated, the flow path of the water lance (14) is thereby not restricted in any way. The water lance flow path originates from the rear manifold (14b), where water is filtered and then dispensed to several pressure tubes. A pressure tube directs water through the body of the water lance to the front manifold (14a). Water reassembles into a single reservoir in this forward manifold and is sent to a water injection nozzle. U.S. Patent Nos. 4,980,120 and 5,19
No. 4,127 describes a fluid dispensing member suitable for use as a water lance in the present invention. The water injection nozzles may be arranged in various ways at the front end of the water lance, but a set of water injection nozzles is provided symmetrically at a 90 degree angle to the water lance,
It is preferred to have one pointing straight up and the other straight down. A remotely controllable sludge lance drive assembly (22) is mounted on the handhole (6) and the lance guide (1) is used with this drive assembly.
2) and the water lance (14) are moved along the part of the steam generator where there is no tube lane. The sludge lance drive assembly (22) includes a belt with pin (18).
Are coupled to servomotors (24) and (26) via active engagement of the holes (16). The lane-to-lane indexing and position calibration of each tube (3) is controlled through computer software using encoder-based position feedback detectors (37) and proximity sensors (35). Position feedback detector (3
7) is a lance guide (12) and a proximity sensor (35)
Are attached to the lance guide heads (34), respectively.

The water lance (14) includes a belt (18) with a pin and a hole (16) in the body of the water lance.
Is laterally moved by the servomotor (26) through the engagement with Servo motors (24) and (26)
However, a water lance (14) is provided so that water can be injected not only between the pipe lanes but also when the water is drawn from the pipe lanes. Servo motors (24) and (26)
Is also adjusted so as not to impose an unreasonable burden on the water lance when an obstacle in the tube lane is detected.

Referring now to FIG. 2, a rotary drive assembly (28) provided with a position feedback detector.
Is connected to the sludge lance drive assembly (22). The rotary drive assembly (28) cleans the tubesheet to the first support plate or between the support plates by one revolution of the lance guide (12) and the water lance (14). The cutting water lance and the sludge height measuring tool may be rotated above the sludge accumulated at an excessive height. One rotation of the rotary drive assembly (28) can remove sludge from the upper and lower halves of the steam generator.
The rotary drive assembly can also be moved at a predetermined angle. Rotary drive assembly (2
8) is best shown in FIG.
0). A rotary bearing assembly (32) facilitates movement of the rotary drive assembly (28).

The servo motors (24) and (30)
Includes digital motion control hardware and amplifiers needed to control positioning of lance guide (12) and water lance (14). Hard-air for this motion control should be chosen to exceed the requirements of the control system so that other options can be added at a later date. Commands from a computer system (not shown) are processed by the servo motors (24) and (30), and converted into control signals for the mechanical system based on data from the encoder.

The commands to the servomotors (24) and (30) are preferably generated from a type 80486 microcomputer station located outside the compartment and continuously staffed during lance operation. Preferably, the microcomputer station uses menu-based, user-friendly software that allows for a relatively easy sequence of commands for a single operation or for a complex combination of operations. When the operator indicates the range, lane, and number of passes to operate the lance with the keyboard or mouse, the control system automatically processes the entire lance process, and if a problem such as blockage or liquid level rises, the operator A warning is issued to indicate that a trouble or pump problem has occurred. Because the software is flexible enough to accept various access points, steam generator pipe patterns, lance actuation plans and reporting options, the control system can be used to provide daily progress reports and graphs. Can also be generated.

[0012] The lance guide is a motor driven tool and, when using an articulated annular sludge lance as described in US patent application Ser. No. 08 / 126,453, the lance guide of the steam generator. The interior of the steam generator is accessed through a handhole and advanced along a central portion of the steam generator without a tube lance and travels along an annular portion around the tube bundle of the steam generator. Various sludge lance tools are passed through the body of the lance guide and emerge from the guide head (34) and between the tubes of the steam generator tube bundle. In a situation limited only by the bars inside the tube bundle, these sludge lance tools typically penetrate the entire tube bundle, including through deep within the accumulated sludge.

[0013] Among the sludge lance tools, a cutting lance is one of the most commonly used. The cutting lance incorporates two high pressure jets for sludge or tube sheet cutting and for cleaning the broach holes above the support plate. Straight water lances containing the water jets are positioned opposite and in front of the cutting lances, which remove scale and soft sludge from the tube, allowing the cutting lances to be passed without restriction. Two other tools, a visual inspection strip and a sludge height measuring instrument, incorporate fiber optics and other special equipment for inspecting the condition of the steam generator before and after performing a lance operation. The water and sludge entrained in the water are removed from another handhole using a high capacity suction system known in the art.

As described in US Pat. Nos. 4,980,120 and 5,194,217, the sludge lances of the present invention may be provided with a high impact plastic such as polycarbonate or acetal and / or , Aluminum, stainless steel, or a metal such as brass, or a combination thereof. In some steam generators, a shroud or inner shell transfers the tube bundle about 8 mm from the tubesheet.
Surround except for the part offset by inches. As shown in FIG. 1, a handhole (6) about 2.5 inches in diameter constitutes one entrance to the section (4) without the tube lane. Another handhole in some steam generators is about 3.5 inches (about 8.9 cm) in diameter. Annular chamber (5)
Has a width dimension of about 3.5 to 4 inches (about 8.9 to 10.1 cm). Of course, other steam generators will have other dimensions and shapes according to their specifications. CAN
The DU (Canadian Heavy Water Reactor) steam generator has a strict water-tightness, so the water lance that can be used has a thickness of about 0.1 inch (about 2.54 mm) and a thickness of about 0.115 inch (about 2.15 mm). 92 mm), or about 0.125 inches (about 3.25 inches).
17 mm), about 1.25 inches (about 3.17 cm) wide or 1.5 inches (3.81 cm) long, about 8 inches long
To 10 feet (2.4 to 3 meters). FIG. 3 shows an articulated annular sludge lance that is remotely controlled using a sludge lance drive assembly (22). Delivery rail (41)
Provides a trajectory that changes to a range of 0 to 90 degrees, and a track member (40) follows this trajectory and moves forward, and the inner and inner peripheral portions of the annular chamber (5) of the steam generator (2) Get in. In another embodiment, the water lance (1
A single flexible track is used to receive the 4) or act as the track itself, and the manipulator head (4) to orient the water lance (14) between the tubes (3).
2) is still used. This flexible track is positioned inside the annular chamber (5) of the steam generator (2).

Water lance to steam generator (14)
The insertion and withdrawal of the lance guide (12) are performed by engaging the pins of the belt with pin (18) in the holes (16) drilled in the water lance (14) and the lance guide (12), and It is preferable to perform active position control as described with respect to the part without lanes. As mentioned earlier, the water lance (14) and lance guide (12), servomotors (24) and (26)
To the drive assembly (22). This drive assembly (22) is connected to a rotary drive assembly (28) via a gear belt assembly (29) shown in FIG. In the production of a steam generator, tie rods are used to hold the support plate. Typically, these tie rods are 3.25 inch long steel members that the lances can obstruct when cleaning the tubes after the steam generator is manufactured. The use of multiple tie rods inside the steam generator leaves a large portion of the steam generator uncleaned using the prior art. According to the method and the sludge lance of the invention, the sludge between the tubes (3) in the steam generator (2) is much more effectively cleaned.

FIG. 4 shows a flexible water lance (1).
4) is shown in a partially retracted state. The flexible water lance (14) is bent in a loop outside the track. In this embodiment, an optional guide channel (44) provides additional support for the lance guide (12) and the flexible water lance (14). Lance guide head (34)
Orients a flexible water lance (14) at any selected location between the tubes of the steam generator. The flexible water lance (14) is illustrated with one end forming a loop when partially retracted. As shown in FIG. 5, the drive assembly (22) for the lance guide and water lance preferably includes two servomotors (24) and (26) mounted perpendicular to the bracket (46). A pulley (20) is fitted inside the bracket (46) together with the belt with pin (18). A bracket for each servomotor itself is positioned on each side of the lance guide (12) and flexible water lance (14), as shown in some figures. The ends of the two brackets (46) adjacent to the steam generator are pivotably connected to each other. With this structure, setting the lance guide (12) and the flexible water lance (14) therein is facilitated by opening the other end of the bracket like a bivalve.
A guide roller assembly (48) helps maintain the water lance (14) for proper orientation. The fastener (50) is manually adjusted to clamp the bracket (46) in a closed state.
8) is engaged with the lance guide (12), and the other pinned belt (18) is preferably engaged with the water lance (14). The drive assembly (22) is attached to the drive mounting assembly (52) using a similar fastener (50). An optional guide support bracket (54) stabilizes the entire assembly in the steam generator.

While the invention has been described with reference to specific embodiments, it will be understood that many modifications can be made within the invention.

[0018]

According to the present invention, the drive assembly is located outside the steam generator so that the drive assembly can be easily accessed, and the drive assembly can be located outside the steam generator.
The first servomotor is connected to the U-shaped lance guide groove.
Engage with this U-shaped lance guide groove through multiple holes
And a third, also located outside the steam generator
2 servo motors and multiple holes in the water lance
To engage with this water lance.
By these figures, the first and second servo motors are illustrated.
It is possible to arrange them side by side as shown,
Drive assembly containing these servo motors
Spatial constraints are much more relaxed than otherwise
In addition to being easier to maintain,
Furthermore, it is also excluded concerned against the harsh environment, out parts can damage the steam generator stops therein
Is rather free, a structure is simple rugged, yet inexpensive manufacturing cost, automatic sludge lance is provided for cleaning the tube bundle inside the steam generator.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a water lance positioned at an appropriate position in a steam generator with the steam generator partially cut away.

FIG. 2 is a perspective view similar to FIG. 1 of another embodiment of the present invention.

FIG. 3 shows a remote steering system for autopiloting an annular articulated sludge lance according to the present invention.
FIG. 3 is a perspective view similar to FIG.

FIG. 4 is a perspective view similar to that of FIGS. 1 to 3, with the water lance partially retracted, but without the steam generator;

FIG. 5 is a front view of a part of an automatic sludge lance according to the present invention.

[Explanation of symbols]

 2 Steam generator 3 Tube 4 Portion without tube lane 6 Hand hole 8 Mounting bracket 10 Automatic sludge lance 12 Lance guide 14 Water lance 14a Front manifold 14b Rear manifold 16 hole 18 Pinned belt 20 Pulley 22 Sludge lance drive assembly 24, 26 Servomotor 28 Rotary drive assembly 30 Servomotor 32 Rotary bearing assembly 34 Lance guide head 35 Proximity sensor 37 Position feedback detector

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F22B 37/54 F22B 37/48 F28G 1/16

Claims (1)

(57) [Claims] 1. Sludge is removed from between tubes in a steam generator.
Automatic sludge lance for remote control, by remote control,
U-shaped lance guide groove that moves to the selected position
To the position of one end positioned in the steam generator.
A U-shaped lance guide groove on which the id head is mounted , and movably stored in the U-shaped lance guide groove;
With the water lance held, by remote control,
U-shaped lancer with U-shaped lance guide groove
Move in the guide groove and move the U-shaped
Exit the guide groove and set the angle to a preset angle by the guide head.
Oriented and predetermined length in tube bundle in steam generator
Extending between the tubes, and further receiving and receiving fluid.
Sludge between the tubes by orienting the fluid
U-shaped from outside of steam generator attached to bracket with water lance having configuration to remove
Generates steam with a water lance through the lance guide groove
For selective positioning in areas where there are no pipe lanes in the machine
The first servo motor of the outside of the steam generator
Through a plurality of holes in the U-shaped lance guide groove
And a first servo engaged with the U-shaped lance guide groove.
The motor and the bracket attached to the
-A second servo motor that controls the movement of the lance
Between the U-shaped lance guide groove and the pipe in the steam generator
Water lance in and out of the guide head
Steam generator to orient it between the tubes in the steam generator.
Multiple holes in the water lance located outside the
Through the second servomotor engaging the water lance
Including a Ta, was to remove the sludge from between the steam generator machine tube
Automatic sludge lance.