WO2016057653A1

WO2016057653A1 - Rotating lance head steam generator lancing system

Info

Publication number: WO2016057653A1
Application number: PCT/US2015/054469
Authority: WO
Inventors: Christos Athanassiu; Michael T. Johnson; Anthony Chesna
Original assignee: Foster-Miller, Inc.
Priority date: 2014-10-10
Filing date: 2015-10-07
Publication date: 2016-04-14
Also published as: KR101989020B1; KR20170066627A

Abstract

Featured is a steam generator cleaning system which may include an articulating lance guide, and an articulating guide rail disposed in the steam generator no tube lane supporting the articulating lance guide and positioning the articulating lance guide proximate a steam generator center region inter-tube lane. A flexible lance is extendible from within the articulating lance guide. The flexible lance preferably includes a head with a tube lane alignment guide including a concave surface for engaging the first tube in one row of tubes in the steam generator at the inter-tube region thereof proximate the center dome/cylinder area. A rotating fluid jet assembly is adjacent the tube lane alignment guide for directing fluid at the center of an inter-tube lane between the first tube in one row of tubes and an adjacent first tube in another row of tubes.

Description

ROTATING LANCE HEAD STEAM GENERATOR LANCING SYSTEM

RELATED APPLICATIONS

This application claims benefit of and priority to U.S. Provisional Application Serial No. 62/062,277 filed October 10, 2014 under 35 U.S.C. §§1 19, 120, 363, 365, and 37 C.F.R. § 1.55 and § 1.78 which is incorporated herein by this reference.

FIELD OF THE INVENTION

This subject invention relates to steam generator cleaning systems.

BACKGROUND OF THE INVENTION

Prior steam generator lance cleaning systems typically use flexible and or rigid tubing lances that are introduced from the No Tube Lane (NTL) region of a steam generator. U.S. Patent Nos. RE 38,542; 7,086,353; 8,468,981 ; and published U.S. Patent Application No. 2009/021 1612 are all incorporated herein by this reference.

Some flexible lances utilize flexible plastic hoses that are encased in either metal or composite material weave. Typically these lances use segmented vertebrae or continuous flexible channel housings and require greater than 3 mm inter-tube gap clearance. With the introduction of steam generators with smaller than 3 mm tube gaps there is a need for effective and efficient means to provide sludge cleaning services.

BRIEF SUMMARY OF THE INVENTION

Featured is a steam generator cleaning system which may include an articulating lance guide and an articulating guide rail disposed in the steam generator no tube lane supporting the articulating lance guide and positioning the articulating lance guide proximate a steam generator center region inter-tube lane. A flexible lance is extendible from within the articulating lance guide. The flexible lance preferably includes a head with a tube lane alignment guide including a concave surface for engaging the first tube in one row of tubes in the steam generator at the inter-tube region thereof proximate the center dome/cylinder area. A rotating fluid jet assembly on the head is closely adjacent the tube lane alignment guide for directing fluid at the center of an inter-tube lane between the first tube in one row of tubes and an adjacent first tube in another row of tubes.

The lance head may further include a nozzle on the rotating fluid jet assembly positioned to offset the jetting force of the fluid jet. In one design, the lance head includes a fixture, the rotating fluid jet assembly includes a barrel rotatable with respect to the fixture, and a fluid fitting is included on the barrel. A drive cable may extend through the flexible lance and lance head fixture and is connected to the rotatable barrel. The cable may be driven by a motor with a controller configured to control the motor to rotate the rotatable barrel via the drive cable at a variable rate of rotation to achieve a linear steam generator tube sheet fluid jet speed. In some embodiments, there is flexible fluid supply hose connected on one end to the lance head fixture, connected on an opposite end to the fluid fitting, and looping around the rotatable barrel. A fluid supply hose extends through the flexible lance and is connected to the lance head fixture. A rigid tube may be connected to the fluid fitting receiving fluid from the flexible fluid supply hose. A nozzle may be included at the distal end of the rigid tube. A fluid fitting on the barrel may include a rearward nozzle producing a counterbalancing water jet, A probe may be included on the fixture and a probe cable extending through the flexible lance.

The subject invention, however, in other embodiments, need not achieve all these objectives and the claims hereof should not be limited to structures or methods capable of achieving these objectives.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Other objects, features, and advantages will occur to those skilled in the art from the following description of a preferred embodiment and the accompanying drawings, in which:

Fig. 1 is a schematic three dimensional front view showing an example of a flexible lance in accordance with embodiments of the invention;

Fig. 2 is shows the lance head of Fig. 1 where the tube lane alignment guide has engaged the first tube in one row of tubes in the steam generator at the inter-tube region and the cleaning water jet rigid tube is deployed into the tube lane;

Fig. 3 is a schematic side view showing the primary components associated with one lance head;

Fig. 4 is a schematic cross-sectional side view showing the primary components associated with one lance head;

Fig. 5 is a schematic view showing the rotating water jets;

Fig. 6 is a schematic cross-sectiona! view showing the rotating water jet barrel; Fig. 7 is a schematic diagram showing the jet barrel drive cable being driven by a motor under the control of a controller;

Fig. 8 is a highly schematic view showing how a linear tube sheet water jet speed is achieved by varying the angular rotation rate of rotating barrel and nozzle shown in Fig. 7;

Fig. 9 is schematic top view showing the articulating guide rail in the inter tube region and the no tube lane of a steam generator;

Fig. 10 is a more detailed view showing the flexible lance head and other components;

Fig.11 is another schematic view showing the articulating lance guide and the flexible lance head; and

Fig. 12 is a schematic cross-sectional view showing how the flexible lance head rotating fluid jet assembly is able to clean the tubes proximate the tubes sheets of the steam generator.

DETAILED DESCRIPTION OF THE INVENTION

Aside from the preferred embodiment or embodiments disclosed below, this invention is capable of other embodiments and of being practiced or being carried out in various ways. Thus, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. If only one embodiment is described herein, the claims hereof are not to be limited to that embodiment.

Moreover, the claims hereof are not to be read restrictively unless there is clear and convincing evidence manifesting a certain exclusion, restriction, or disclaimer.

One function of this invention is to provide means for breaking up sludge deposits, hard or soft, from the inter-tube region of steam generators with restrictive inter-tube gaps and access, such as those found in models CE80, OPR-1G00 and APR- 1400 Nuclear Power Plants and others.

All of the power plants cited above, namely CE80, OPR-1000 and APR- 1400 use steam generators with a very small NTL clearance and less than 3 mm wide inter- tube gaps. The small NTL clearance precludes the use of conventional sludge lancing systems for cleaning the entire steam generator inter-tube region because the equipment is too big to operate from the restrictive NTL and center region areas. All existing lancing technologies fail to address cleaning of inter-tube lanes that start from around the center dome/cylinder area predictably and efficiently. Cleaning the inter- tube lanes from the NTL towards the annulus allows the sprays to impact the hard/soft sludge, located near the center region of the steam, generator, with much greater force than spraying approaches that start at the annulus region. The stand-off distance for the nozzle to the sludge is as short as possible to maximize the force of the sprays.

In one aspect, this invention addresses the need to provide inter-tube high pressure water cleaning for steam generator designs that have very limited access from the No Tube Lane (NTL), with very small tube gaps and a center stay dome/cylinder such as models CE80, OPR- 1000, APR- 1400. The system described herein accesses steam generator inter-tube lanes that start around the stay dome/cylinder of said steam generators and extend to the steam generator annulus region. One proposed sludge lancing system shown in Figs. 1 -6 addresses the need for accessing the center region inter-tube lanes 102 shown in Fig, 2 and provides predictable means for sludge removal. The proposed sludge lancing system includes means for accurately delivering a flexible lance 10, Fig. 1 with a head 12 that can be precisely positioned at the front of a tube lane which is defined as the space between two rows of tubes. A rotating barrel 20 delivers high pressure and flow of

demineialized water through a high efficiency nozzle that is guided into a tube lane by a rigid tube and rotating at a controllable linear tube sheet speed that enables the cleaning water jet to travel from the center of a steam generator to the outer annulus region. A secondary nozzle may be incorporated in the rotating lance head and its purpose is to provide an opposing jetting force to the cleaning nozzle and thus stabilizing the rotating head "zero net jetting force". Centering of the cleaning nozzle jet in a tube gap is important to the cleaning efficiency. Water jet coherency is influenced by the distance it travels in open air. The smaller the distance before a water jet enters a tube lane which acts as a water channel and not open air, the more coherent it stays, and the more power it delivers on its target the inter-tube sludge. Prior art systems fail in predictably positioning a nozzle, precisely at the center of a tube lane opening, and their standoff distance varies between 20mm to several hundred millimeters. Having the cleaning jet nozzle positioned in the tube lane by a rigid tube eliminates this open air tube gap. Additionally, a cleaning jet which rotates at a linear tube sheet speed, between the bottom dead center (at the entrance of a tube lane) and the steam generator annulus, may be important for transporting the inter- tube sludge to the annulus region where it can be effectively suctioned. Because prior art systems mostly spray from a large standoff distance, the water jet coherency deteriorates and mostly hits the first tube surfaces instead of entering a lane, and because they do not rotate at an angular speed which provides an effective linear tube sheet speed, they fail to predictable and efficiently clean the center region of the stated steam generators.

The flexible lance preferably extends from and retracts within the lance guide 1 1 and includes a head with the concave tube alignment guide 14. The lance head also includes a rotating fluid jet assembly. A rotating barrel rotates 90° with respect to the lance head and may be driven by a drive cable.

One or more water lines are carried by the flexible lance and deliver water to the lance head and a fitting fixed to the lance head. A flexible water supply hose is connected on one end to the lance head fitting and gently curves and loops around the rotating barrel so the water supply hose can be connected to a fitting fixed to the rotating barrel. From there, the water enters a rigid tube which extends beyond the alignment guide and well into the gap between adjacent tubes of the steam generator. There is a high efficiency nozzle at the end of the rigid tube. The rigid tube may be made of stainless steel.

This configuration reduces the turns and/or bends the water must travel and provides sufficient water pressure at the exit of the rigid tube for cleaning while still allowing the rigid tube to be rotated. The supply hose coils and uncoils as the rotating barrel rotates.

Fig. 1 shows an example of a flexible lance 10 within articulating lance guide 1 1 supported by an articulating guide rail. Lance 10 includes head 12 with a tube alignment guide 14 having a concave front face 16 for engaging the first tube in one row of tubes in a steam generator at the inter-tube region thereof proximate the center dome/cylinder area 102, Fig. 2.

Head 12 is configured to include rotating fluid jet assembly 20 adjacent to tube alignment guide for directing fluid at the center of an inner-tube lane 13 between the first tube 15 in one row of tubes and an adjacent first tube 17 in another row of tubes as shown in Fig. 2.

In one preferred embodiment, fluid jet assembly 20. Fig. 1, includes lance head fixture 22 and barrel 24 rotatable with respect to fixture 22 via a bearing or the like. Barrel 24 includes fluid fitting 26. Tube 30 is connected to fluid fitting 26 extends forward of guide 14, and produces the fluid (e.g., water) cleaning jet 32 via distal tube high efficiency nozzle 34. Fitting 26 may also include nozzle 36 positioned to produce a cleaning jet 38 in a direction opposite cleaning jet 32 to offset or counterbalance the force produced by jet 32. Fixture 22 may further include camera/video probe 40. Fluid fitting 26 on barrel 20 is positioned just behind concave surface 16 and offset as shown so tube 30 can be placed between the narrow 2.9 mm gap between tubes in the steam generator as shown in Fig. 2. Guide 14 includes inwardly displaced side wall 17 to allow tube 30 to proceed forward of concave surface 16.

To rotate barrel 24 with respect to fixture 22, cable 50 extends through lance

10 as shown and connects around barrel 20. One or more fluid supply lines 52a, 52b also extend within lance 10 and are connected to fluid fixture 22. Flexible fluid supply hose is connected on one end to fluid fitting 26, connected on the other end to fixture 22, and loops around barrel 20 as shown to deliver fluid from the fluid supply line(s) to the tube 30 and nozzle 34. Video/camera cable 60 also extends within lance 10 to power probe 40 and transmit images through the lance.

As shown in Fig. 3, lance 10 preferably includes individual articulating segments 70a, 70b, 70, and the like configured to receive therethrough cable 50, lines

52, probe cable 60, and optional probe purge conduit 72 [compressed air?].

Fig. 4 shows the interior of lance head fixture 22 with channels 80a and 80b therein for cable 50 used to rotate barrel 24 with respect to fixture 22 and to thus rotate fitting 26. The interior of lance head fixture 22 also includes fluid connections 84 between supply line(s) 52 and hose 54 and the fitting nozzle which provides the counterbalancing jet 38. Lance safety cables 86a and 86b may also be provided. Figs. 5 and 6 also show aspects of the rotating fluid jet assembly. Fig. 7 shows the barrel drive cable being driven by a motor M under the control of controller 51. Preferably, the controller is configured (e.g., programmed) to control the motor M to rotate the rotatable barrel via the cable at a variable rate of rotation to achieve a linear steam generator tube sheet fluid jet speed. That is, the jet spray impinging on the tube sheet as shown in Fig. 8 advances across the tube sheet at a constant rate of, for example, 50 mm/sec.

The proposed sludge lancing system may operate from both the "No Tube Lane" 100 Figs. 9- 12 and the center region 102 of steam generator 104. The system may include a temporarily installed articulating guide rail 106 which will support an articulating lance guide 1 1 1 and the flexible lance 10 which houses the rotating spray head. The lance guide includes means to electrically move it along the rail via use of an electric motor equipped with encoder feedback for precise positioning the lance head in front of a tube gap opening. It may include means for driving the flexible lance extending and retracting it from the first tube in a tube lane using an electric motor equipped with encoder feedback for accurate lance head standoff distance positioning. The lance head includes concave means for engaging half of the first tube curvature for precisely positioning the rotating lance head water jet at the center of a tube lane. The cleaning water jet rigid tube and nozzle then rotates to spray water at the tube sheet below the nozzle and rotates to spray water at the tube sheet until the annulus is reached. Furthermore, the lance head tube curvature engaging component may include a sensor 108, Fig. 1 that measures the distance between the first tube and the curved lance head engaging component which enables the system operator and or automated computer operations to protect against pushing hard against the first tube lane tube. The rotatable barrel includes means for affecting its rotation so that the inter-tube jetting nozzle rotates between its dead bottom center position, to the horizontal 90° position. The nozzle rotation is controlled by mechanically connecting two opposing points on the rotating head outer diameter, using a cable of high strength metallic and or other high strength materials such as Kevlar, which are connected to an electric motor equipped with a rotating drum, or via use of a linear motor. Once one inter-tube lane is cleaned, the lance head is repositioned to clean another inter-tube lane.

The rotatable lance head motor M, Figs. 7-8 may be controlled via controller 51 , programmed to effect rotation that produces a linear tube sheet speed of the water jet. An alternative embodiment includes an extendable or fixed nozzle, long enough 5 054469

1 1 to physically enter a tube lane after the lance head has been precisely aligned at the tube gap, ensuring all of the available water jet is directed at a sludge pile at a shorted standoff distance.

The lance head may include a video probe or camera and light pipe which is used by the operator for visual feedback.

Featured is a controllable flexible lance head able to predictably and precisely position a rotating nozzle housing in front of a steam generator tube lane opening, in particular in the center region of CE80, OPR.- 1000 and APR- 1400 types, water jet spraying either from a very short standoff distance or inside a tube lane maximizing the water jet cleaning effectiveness.

Another feature is the introduction of a linear tube sheet water jet speed which affects an even sweep of the entire tube lane length for even tube sheet sludge removal. Another feature is the introduction of an articulating lance guide which enables controllable and precise positioning on the flexible lance head in front of a tube lane. Still, another feature is the "zero net jetting force design" of the lance head, affected by the introduction of an opposing jet nozzle in line with the cleaning jet.

Although specific features of the invention are shown in some drawings and not in others, this is for convenience only as each feature may be combined with any or all of the other features in accordance with the invention. The words "including", "comprising", "having", and "with" as used herein are to be interpreted broadly and comprehensively and are not limited to any physical interconnection. Moreover, any embodiments disclosed in the subject application are not to be taken as the only possible embodiments. Other embodiments will occur to those skilled in the art and are within the following claims.

In addition, any amendment presented during the prosecution of the patent application for this patent is not a disclaimer of any claim element presented in the application as filed: those skilled in the art cannot reasonably be expected to draft a claim that would literally encompass all possible equivalents, many equivalents will be unforeseeable at the time of the amendment and are beyond a fair interpretation of what is to be surrendered (if anything), the rationale underlying the amendment may bear no more than a tangential relation to many equivalents, and/or there are many other reasons the applicant can not be expected to describe certain insubstantial substitutes for any claim element amended.

What is claimed is:

Claims

1. A steam generator cleaning system comprising:

an articulating lance guide;

an articulating guide rail disposed in the steam generator no tube lane supporting the articulating lance guide and positioning the articulating lance guide proximate a steam generator center region inter-tube lane; and

a flexible lance extendible from within the articulating lance guide, the flexible lance including:

a head with a tuabe lane alignment guide including a concave surface for engaging the first tube in one row of tubes in the steam generator at the inter-tube region thereof proximate the center dome/cylinder area, and

a rotating fluid jet assembly adjacent the tube lane alignment guide for directing fluid at the center of an inter-tube lane between said first tube in one row of tubes and an adjacent first tube in another row of tubes.

2. The steam generator cleaning system of claim 1 further including a nozzle on the rotating fluid jet assembly positioned to offset thejetting force of the fluid jet.

3. The steam generator cleaning system of claim 1 in which the lance head includes a fixture, the rotating fluid jet assembly includes a barrel rotatable with respect to said fixture, and a fluid fitting is included on the barrel.

4. The steam generator cleaning system of claim 3 further including a drive cable extending through the flexible lance and lance head fixture and connected to the rotatable barrel.

5. The steam generator cleaning system of claim 4 in which the cable is controlled by a motor.

6. The steam generator cleaning system of claim 5 further including a controller configured to control the motor to rotate the rotatable barrel via the drive cable at a variable rate of rotation to achieve a linear steam generator tube sheet fluid jet speed.

7. The steam generator cleaning system of claim 3 in which there is flexible fluid supply hose connected on one end to the lance head fixture, connected on an opposite end to the fluid fitting, and looping around the rotatable barrel.

8. The steam generator cleaning system of claim 7 further including a fluid supply line extending through the flexible lance and connected to the lance head fixture.

9. The steam generator cleaning system of claim 7 further including a rigid tube connected to the fluid fitting receiving fluid from the flexible fluid supply line.

10. The steam generator cleaning system of claim 9 further including a nozzle at the distal end of the rigid tube.

1 1. The steam generator cleaning system of claim 3 in which said fluid fitting on the barrel includes a rearward nozzle producing a counterbalancing water jet.

12. The steam generator cleaning system of claim 3 further including a probe on the fixture and a probe cable extending through the flexible lance.

13. A steam generator cleaning flexible lance comprising:

a head with a tube lane alignment guide including a concave surface for engaging the first tube in one row of tubes in the steam generator at the inter-tube region thereof proximate the center dome/cylinder area; and

14. The steam generator cleaning flexible lance of claim 13 further including a nozzle on the rotating fluid jet assembly positioned to offset the jetting force of the fluid jet.

15. The steam generator cleaning flexible lance of claim 13 in which the iance head includes a fixture, the rotating fluid jet assembly includes a barrel rotatable with respect to said fixture, and a fluid fitting is included on the barrel.

16. The steam generator cleaning flexible lance of claim 15 further including a drive cable extending through the flexible lance and lance head fixture and connected to the rotatable barrel.

17. The steam generator cleaning flexible lance of claim 16 in which the cable is controlled by a motor.

18. The steam generator cleaning flexible lance of claim 17 further including a controller configured to control the motor to rotate the rotatable barrel via the drive cable at a variable rate of rotation to achieve a linear steam generator tube sheet fluid jet speed.

19. The steam generator cleaning flexible lance of claim 15 in which there is flexible fluid supply hose connected on one end to the lance head fixture, connected on an opposite end to the fluid fitting, and looping around the rotatable barrel.

20. The steam generator cleaning flexible lance of claim 19 further including a rigid tube connected to the fluid fitting receiving fluid from the flexible fluid supply hose.

21. The steam generator cleaning flexible lance of claim 20 further including a fluid supply line extending within the lance and connected to the fixture.

22. The steam generator cleaning flexible lance of claim 21 further including a nozzle at the distal end of the rigid tube.

23. The steam generator cleaning flexible lance of claim 15 in which said fluid fitting on the barrel includes a rearward nozzle providing a counterbalancing water jet.

24. The steam generator cleaning flexible lance of claim 15 further including a probe on the fixture and a probe cable extending through the flexible lance.

25. A steam generator cleaning flexible lance comprising:

a head with a tube lane alignment guide including a concave surface for engaging the first tube in one row of tubes in the steam generator at the inter-tube region thereof proximate the center dome/cylinder area;

a fixture on the head behind the guide;

a rotating fluid jet barrel on the fixture; and

a fluid fitting on the barrel for directing a cleaning fluid jet between said tubes.

26. The steam generator cleaning lance of claim 25 further including a nozzle on the fluid fitting positioned to offset the jetting force of the fluid jet.

27. The steam generator cleaning lance of claim 25 further including a drive cable extending through the flexible lance and lance head fixture and connected to the rotatable barrel.

28. The steam generator cleaning lance of claim 25 in which there is flexible fluid supply hose connected on one end to the lance head fixture, connected on an opposite end to the fluid fitting, and looping around the rotatable barrel.

29. The steam generator cleaning lance of claim 28 further including a rigid tube connected to the fluid fitting receiving fluid from the flexible fluid supply line.

30. The steam generator cleaning lance of claim 29 further including a fluid supply line extending through the lance and connected to the fixture.