Remote surface treatment system and method

Abstract

The system (100) remotely grinds and compresses a working surface (14), including surfaces formed by electrical discharge machining. The bridge (101) is fixed around the periphery of the surface (14) and may carry a spindle (120) that rotatably extends downward and carries an abrading assembly (200). The abrading assembly (200) can press against the surface (14) while abrading the surface (14) with increased force. The abrading machine (300) can move vertically around the periphery of the surface (14). The system (100) can be remotely operated with a pneumatic slide (210), a hydraulic motor (205), and / or a stepper motor (110). Electrical discharge machined spots, including those in nuclear facilities and deep seas, can be removed with such a system without manual or direct operator interface.

Description

[Technical Field]

[0001] 1 is a cross-sectional view of a related art manway 11 of a shroud support of a nuclear reactor 10, which is typically submerged deep below the liquid coolant during reactor maintenance. During such maintenance, the manway 11 may require repair or replacement of the cover, which may result in weld defects. Thus, during an outage to repair the manway 11, the manway 11 can be cut out and a bolted-on replacement manway cover added. [Background technology]

[0002] Like electrical discharge machining, material is removed from the edges of the bore to create a precise and uniform hole 15 in the manway 11. Because the affected area and cover may be large, the hole 15 may need to have a diameter d approaching 2 feet (approximately 60.96 centimeters). Also, due to the thickness of the manway 11, the hole 15 may be 1 to 3 inches deep (approximately 2.54 to 7.62 cm). As such, the interior surface of the hole 15 may be relatively large and may include ledges to accommodate repairs, covers, etc. For example, the interior surface of the hole 15 may include the bore 13 and the spot surface 14. Summary of the Invention [Means for solving the problem]

[0003] Exemplary embodiments include an assembly system for remotely treating a surface with a desired abrasion and / or compression. An exemplary embodiment system includes a bridge for securing to the surface to be treated. A rotatable spindle extends downward from the bridge and is drivable. The spindle may include a polisher that rotates or moves in contact with the surface to be treated. The polisher further includes a biasing element that presses the polisher against the surface, exerting compressive stresses, up to tens of pounds. The polisher may also include a rounded filament brush. The spindle rotates about a separate axis, allowing the polisher to move partially or completely around the surface to be treated. All embodiment systems are remotely operable, with one or more drives mounted on the bridge and polisher for simultaneous motion and actuation. Such drives may also allow the polisher to move up and down. For example, pneumatic slides, hydraulic motors, and / or stepper motors may be used to remotely actuate the actuation and rotation. Exemplary embodiments can be used on spot surfaces deep within a nuclear reactor to remove recast layers that may form after EDM machining of spot surfaces and through-bores where manual or direct operator interface is not possible. [Brief explanation of the drawings]

[0004] [Figure 1] FIG. 1 is an illustration showing a related art manway inside a nuclear reactor. [Figure 2] FIG. 2 is an explanatory diagram illustrating an example of a bridge assembly according to one embodiment. [Figure 3] FIG. 3 is an explanatory diagram illustrating an example of a polishing assembly according to one embodiment. [Figure 4A] FIG. 4A is a schematic cross-sectional view of an example bore grinder according to one embodiment, including a vertically oriented grinding assembly mated with a bore grinding wheel. [Figure 4B] FIG. 4B is a schematic cross-sectional view of a bore grinder according to an exemplary embodiment with the grinding wheel withdrawn vertically downward. [Figure 4C] FIG. 4C is a schematic cross-sectional view of an example embodiment of a bore polisher with the polishing assembly separated from the bore polisher and rotated about multiple axes. DETAILED DESCRIPTION OF THE INVENTION

[0005] Exemplary embodiments will become more apparent from a detailed description of the accompanying drawings, in which like elements are represented by like reference numerals, which are given for purposes of illustration and therefore not of limitation to the terms they depict.

[0006] Because this is a patent document, general and broad rules of interpretation should be applied when reading it. Everything described in this document is an example of subject matter encompassed by the claims appended below. Specific structural and functional details disclosed herein are merely intended to illustrate how to make and use the examples. Several different embodiments and methods not specifically disclosed herein may fall within the scope of the claims. Accordingly, the claims may be embodied in many alternative forms and should not be interpreted as limited to only the examples set forth herein.

[0007] Although ordinal terms such as "first" and "second" may be used herein to describe various elements, it will be understood that these elements are not limited to any particular order by these terms. These terms are used solely to distinguish one element from another. The presence of a "second" or higher ordinal number simply indicates that that number of elements must be present, not necessarily related in any way by any other relationship. For example, a first element could be referred to as a second element, and similarly, a second element could be referred to as a first element, without departing from the scope of the illustrated embodiment or method. As used herein, the terms "and," "or," and "and / or" include all combinations of one or more of the associated listed items, unless expressly indicated that only a single item, a subgroup of items, or all items are present. The use of "etc." is defined as "et cetera," indicating the inclusion of all other elements belonging to the same group of the preceding item, in any combination of one or more of "and / or."

[0008] When an element is referred to as being "connected," "coupled," "mated," "attached," "secured," or the like, to another element, it is understood that the element may be directly connected to the other element, or that there may be intervening elements. Conversely, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements. Other terms expressing the relationship between elements should be interpreted similarly (e.g., "between" and "direct between," and "adjacent" and "direct adjacent," etc.). Similarly, terms such as "communicatively connected" include all variations of information exchange and routing between two electronic devices, including intermediary devices, networks, etc., whether wirelessly connected or not.

[0009] As used herein, the singular forms "a," "an," and "the" are intended to include both the singular and the plural unless the language explicitly dictates otherwise. Indefinite articles such as "a" and "an" introduce or refer to any modified term, whether previously introduced or not, while definite articles such as "the" refer to the same term previously introduced. Thus, "a" or "an" are understood to modify an item that has been previously introduced or is acknowledged to be new, and definite articles modify the same item as immediately presented. It will be further understood that the terms "comprises," "comprising," "includes," and / or "including," as used herein, specify the presence of stated features, properties, steps, operations, elements, and / or components, but do not themselves exclude the presence or addition of one or more other features, properties, steps, operations, elements, components, and / or groups thereof.

[0010] The structures and operations described below may differ in the order depicted in the figures. For example, two operations and / or figures shown in succession may in fact be performed simultaneously or in the reverse order depending on the functionality / acts involved. Similarly, individual operations within the exemplary methods described below may be performed repeatedly, either individually or sequentially, to provide a loop or other sequence of operations apart from the single operations described below. Any embodiment or method having the features and functions described below, in any workable combination, should be deemed to be within the scope of the exemplary embodiments.

[0011] As used herein, "axial" and "vertical" refer to the same up-down direction oriented along the longitudinal axis of the reactor, often oriented along the force of gravity. "Transverse" and "horizontal" refer to directions perpendicular to the "axial" direction and lateral directions oriented in a single plane at a particular axial height.

[0012] The inventors have recognized that electrical discharge machining, like other material removal operations, can leave a recast or cold-worked layer on the material being machined. This layer has undesirable characteristics at the interface with the cover or other repairs, such as roughness and brittleness of the material. In remote locations and / or underwater processes, such as deep reactor repairs, this layer cannot be removed directly or manually. The inventors have further recognized that remote shot peening and / or laser treatment may not adequately remove the recast layer and may not impart the necessary compression to strengthen or uniform the material. Laser and shot peening may also be difficult to implement in deep, remote locations, especially in a timely combination. The exemplary embodiments described below uniquely enable the solution of these and other challenges discovered by the inventors.

[0013] The present invention is a system for remotely treating a surface and a method for using the same at a spot surface of a nuclear reactor. In contrast to the present invention, the several exemplary embodiments and exemplary methods described below represent only a subset of the various different configurations that can be used as and / or in conjunction with the present invention.

[0014] FIG. 2 is an illustration of an exemplary embodiment of a bridge assembly 100 configured to remotely position grinding and / or smoothing elements on a work surface. While the surfaces described in connection with the exemplary embodiment include bores and spot surfaces deep within a nuclear reactor, it is understood that the exemplary embodiment can be used in connection with any type of surface requiring remote treatment, such as inside piping, holding tanks or pools, or areas with restricted access. As shown in FIG. 2, the bridge assembly 100 includes a bridge 101 that may have a "U" shape with a body and legs that can be positioned above or away from the surface. The legs of the bridge 101 can be secured to or seated against a component having a surface, such as a spot surface, to be treated. Anchors (shown in FIGS. 4A-4C) may also be used as a fastener between the legs of the bridge 101 and the component. The bridge 101 may have other shapes and configurations to better fit and / or access the surface to be worked on.

[0015] The bridge assembly 100 of the exemplary embodiment includes one or more drives that provide power to various components, such as a spindle 120 that is rotatable relative to the work surface. For example, the bridge assembly 100 may include a stepper motor 110 that rotates the spindle 120 relative to the bridge 101. The stepper motor 110 may be connected to the spindle assembly 120 via a transmission 115, which may be a chain that meshes with gears on the spindle 120 at any desired rotation ratio, such as a 2:1 ratio between the stepper motor 110 and the spindle 120. Similarly, a direct drive or any other type of power may be used to rotate the spindle assembly relative to the work surface. The spindle 120 may be rotatably seated in the center of the bridge 101 to allow full rotation of the spindle 120 about a central vertical axis of the bridge 101.

[0016] Motor 110, as well as other drive devices and devices in the exemplary embodiment, may be connected to controls, operators, data, and / or power via umbilical connection 105. Alternatively, a local power source and wireless communication may be used to power and control the exemplary embodiment. Spindle 120 may connect to, power, and / or control polishing assembly 200 and / or bore polisher 300 via connections 102 and 105. For example, connection 103 may carry pneumatic lines, electrical lines, and / or data connections to power bore polisher 300, while connection 102 may carry hydraulic power, electricity, data, etc. to polishing assembly 200. Through all these connections and power arrangements, bridge assembly 100 in the exemplary embodiment can be deployed in remote areas, such as deep within piping or a flooded nuclear reactor, and operate with desired characteristics.

[0017] The spindle 120 connects to tools necessary to work on the surface below the bridge assembly 100. As shown in FIG. 2, for example, a grinding assembly 200 may be connected to and rotated by the spindle 120. As shown in FIG. 3, the grinding assembly 200 includes a grinding cradle 211 coupled to the spindle assembly 120, and a rotatable grinding surface 201, pneumatic slide 210, and hydraulic motor 205 may be connected to the spindle 120 to carry the same. The grinding surface 201 is rotatable about a transverse or angular axis to grind away the EDM recast from the impacted surface. As shown in FIG. 3, the pneumatic slide 210 can move the motor 205 and grinding surface 201 horizontally and vertically, for example, to reach all sides of the spot surface 15. The pneumatic slide 210 may provide a large force directed along the internal rotational axis of the grinding surface 201. For example, the pneumatic slide 210 can extend between the polishing pedestal 211 and the polishing surface 201 with a maximum force of approximately 12 pounds (approximately 5.44 kg) per ½ inch (approximately 1.27 cm) of polishing surface width. Higher levels of force, such as approximately 60 to 70 pounds (approximately 27.21 to 31.75 kg) applied to a 5 to 6 inch (approximately 12.7 cm to 15.24 cm) circular polishing surface 201, will polish a larger recast layer and is sufficient to remove the recast material and impart compressive stress to most metal surfaces. For example, in a nuclear reactor shroud support, sufficient surface removal and compression can provide a good working surface that will not be subject to further degradation within the reactor.

[0018] The polishing surface 201 may be circular, for example, up to about 5.5 inches (about 13.97 cm) in diameter, and is driven at an angle by a hydraulic motor 205, which may have a separate or local power source. The hydraulic motor 205 may be a positive displacement motor, which allows the polishing surface 201 to maintain a constant speed even under heavier polishing pressures. For example, the polishing surface 201 may be driven at about 50 ft / s (about 15.24 m / s) or greater, or about 2000 rpm. The polishing surface 201 may use any abrasive material to achieve the desired surface finish, such as an about 80-grit silicon carbide filament surface with a grit loading of about 30-40% by weight. The polishing assembly 200 may position the polishing surface 201 at about 10 degrees relative to the spot surface 14 (FIG. 1).

[0019] 4A-4C are diagrams illustrating an example embodiment abrading assembly 200 carried by an example embodiment bridge assembly 100 in various configurations for abrading surfaces 13 and 14 of spot surface 15 in an example method for preparing a nuclear reactor spot surface for repair during a maintenance period. As shown in FIGS. 4A-4C, bridge 101 may be attached to a surface against which spot surface 15 is formed by electrical discharge machining. Abrading assembly 200 is lowered from spindle assembly 120 onto spot surface 15 to contact surfaces 13 and 14 against abrading surface 201.

[0020] The abrasive surface 201 can be rotated about its internal axis by a hydraulic motor 205 or other drive device of assemblies 100 and / or 200 with the desired pressure and movement. For example, the spindle 120 can be rotated about its central axis by a stepper motor 110 to orbit or cycle the abrasive assembly 200 around the spot surface 15. In this manner, the abrasive surface 201 can travel along the entire continuous surface of the spot surface 14 and bore surface 13, removing and compressing the recast layer. Simultaneously, the pneumatic slide 210 can expand to push the abrasive surface 201 away from the abrasive support 211, providing the desired abrasive force or pressure.

[0021] In FIG. 4A, the polishing assembly 200 is oriented vertically and mated with a bore polishing wheel 301 of a bore polisher 300. A pneumatic slide 210 (FIG. 3) may press the assembly 200 vertically along axis 302 (FIG. 4B). In this position, the polishing wheel 301 can polish bore surfaces 13 and 14 as the wheel 301 rotates about axis 302. In FIG. 4B, the polishing wheel 301 is pulled vertically downward by the pneumatic slide 201 along axis 302 to polish the vertical side of surface 13. In FIG. 4C, the polishing assembly 200 is detached from the bore polisher 300 and rotated about several axes to contact the spot surface 14.

[0022] The hydraulic motor 205 and stepper motor 110 have sufficient power to continue driving the polishing surface 201 at several thousand revolutions per minute at these positions and pressures without torqueing it out of position. All of the drives, including the hydraulic motor 205, stepper motor 110, and pneumatic slide 210, can be powered locally or remotely via appropriate connections and can be controlled and relayed data via the umbilical connection 105 (FIG. 2). The continuous surface-to-surface polishing achieved by the rotation of the polishing surface 201, the pressure from the pneumatic slide 210, and the rotation of the spindle 120 to feed surfaces 13 and 14 is achieved by the combined action of these components to remove all recast layers and provide the desired uniform compressive force throughout.

[0023] Exemplary embodiment assemblies 100 and 200 may be formed from materials compatible with the operating nuclear reactor environment, including materials that maintain their physical properties when exposed to high-temperature fluids and radiation. For example, metals such as stainless steel and iron, nickel, and zirconium alloys may be used for the assembly components. Similarly, direct connections and all other direct contacts between different components may be smoothed and formed from alternating or other compatible materials to prevent seizure, fouling, or metal-to-metal reactions.

[0024] While exemplary embodiments and methods have been described above, those skilled in the art will recognize that the exemplary embodiments can be modified and substituted through routine experimentation while still falling within the scope of the following claims. For example, any number of different surfaces can be polished with an assembly of the exemplary embodiments simply by appropriate sizing and positioning. Such variations are not considered a departure from the scope of the claims.

Claims

1. A system (100) for polishing a remote surface (14), comprising: a bridge (101) shaped to be fixed around the periphery of said surface (14); a spindle (120) coupled to the bridge (101) and rotatable about a first axis; a grinding assembly (200) secured to the spindle (120) below the bridge (101); Equipped with The polishing assembly (200) includes a polishing surface (201) rotatable about a second axis at the center of the polishing surface (201) and a pneumatic slide (210) configured to extend, the extension of the pneumatic slide (210) pressing the polishing surface (201) against the remote surface (14) in the direction of the second axis.

2. 10. The system of claim 1, wherein the pneumatic slide is configured to apply a force of at least 12 pounds per inch of width of the polishing surface.

3. 2. The system (100) of claim 1, wherein the polishing assembly (200) further comprises a hydraulic motor (205) configured to rotate the polishing surface (201) about the second axis.

4. 4. The system (100) of claim 3, wherein the hydraulic motor (205) is configured to rotate the abrasive surface (201) at approximately 2000 revolutions per minute.

5. 2. The system (100) of claim 1, further comprising a stepper motor (110) connected to the spindle (120) and configured to rotate the spindle (120) about the first axis relative to the bridge (101).

6. 6. The system (100) of claim 5, wherein the spindle (120) is positioned in the center of the bridge (101) and extends below the bridge, and the polishing assembly (200) extends transversely from the spindle (120) to reach the surface (14) for polishing below the bridge (101).

7. The system (100) of claim 1, wherein the polishing surface (201) is rotatable up to about 10 degrees from horizontal.

8. The system (100) of claim 1, wherein the abrasive surface (201) is about 80 grit silicon carbide.

9. The system (100) of claim 1, wherein the polishing assembly (200) is rotatable 360 ​​degrees on the second axis.

10. A method of preparing a spot surface (14) of a nuclear facility, comprising: Fixing a bridge assembly (100) around the periphery of the spot surface (14); moving the polishing surface (201) across the spot surface (14) in a plane containing the polishing surface (201) using a pneumatic slide (210) and spindle (120) of a polishing assembly (200) fixed below the bridge assembly (100) and located remote from an operator; rotating the polishing surface (201) about a second axis at the center of the polishing surface (201) using a motor (205) in the polishing assembly (200); Extending a pneumatic slide (210) in the abrasive assembly (200) to bias the abrasive surface (201) toward the spot surface (14) in the direction of the second axis; 1. A method for preparing a spot surface (14) of a nuclear facility, comprising:

11. 11. The method of claim 10, wherein the moving and biasing steps occur entirely underwater and the operator is entirely outside of the water.

12. 11. The method of claim 10, wherein the biasing step biases the abrasive surface (201) with a force of about 12 pounds (about 5.44 kg) per half inch width (about 1.27 cm) of the abrasive surface (201).

13. 13. The method of claim 12, wherein the biasing step is performed using a pneumatic slide (210) and the moving step is performed using a hydraulic motor (205).

14. 11. The method of claim 10, further comprising rotating the polishing surface (201) using a bridge (101) and spindle (120) remote from the operator so as to polish the entire circumference of the surface (14) of the spot surface.

15. 11. The method of claim 10, wherein the abrasive surface (201) is about 80 grit silicon carbide, and the moving and energizing steps remove an EDM recast layer from the spot surface and impart a compressive stress to the surface (14).

16. 11. The method of claim 10, further comprising rotating the polishing surface (201) to about 10 degrees from horizontal.

17. 11. The method of claim 10, wherein the rotating step comprises rotating the polishing surface (201) relative to the spot surface (14) at least 2000 revolutions per minute.

18. The method of claim 10, further comprising the step of positioning the polishing assembly (200) above the spot plane (14) by fastening the polishing assembly (200) to the bridge assembly (100).

19. 20. The method of claim 18, further comprising the step of electro-discharge machining the surface (14) to form the spot surface.

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