Patent ID: 12257663

DETAILED DESCRIPTION

Because this is a patent document, general, broad rules of construction should be applied when reading it. Everything described and shown in this document is an example of subject matter falling within the scope of the claims, appended below. Any specific structural and functional details disclosed herein are merely for purposes of describing how to make and use examples. Several different embodiments and methods not specifically disclosed herein may fall within the claim scope; as such, the claims may be embodied in many alternate forms and should not be construed as limited to only examples set forth herein.

It will be understood that, although the ordinal terms “first,” “second,” etc. may be used herein to describe various elements, these elements should not be limited to any order by these terms. These terms are used only to distinguish one element from another; where there are “second” or higher ordinals, there merely must be that many number of elements, without necessarily any difference or other relationship. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments or methods. As used herein, the terms “and,” “or,” and “and/or” include all combinations of one or more of the associated listed items unless it is clearly indicated that only a single item, subgroup of items, or all items are present. The use of “etc.” is defined as “et cetera” and indicates the inclusion of all other elements belonging to the same group of the preceding items, in any “and/or” combination(s).

It will be understood that when an element is referred to as being “connected,” “coupled,” “mated,” “attached,” “fixed,” etc. to another element, it can be directly connected to the other element, or intervening elements may be present. In contrast, when an element is referred to as being “directly connected,” “directly coupled,” etc. to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). Similarly, a term such as “communicatively connected” includes all variations of information exchange and routing between two electronic devices, including intermediary devices, networks, etc., connected wirelessly or not.

As used herein, the singular forms “a,” “an,” and the are intended to include both the singular and plural forms, unless the language explicitly indicates otherwise. Indefinite articles like “a” and “an” introduce or refer to any modified term, both previously-introduced and not, while definite articles like “the” refer to a same previously-introduced term; as such, it is understood that “a” or “an” modify items that are permitted to be previously-introduced or new, while definite articles modify an item that is the same as immediately previously presented. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including,” when used herein, specify the presence of stated features, characteristics, steps, operations, elements, and/or components, but do not themselves preclude the presence or addition of one or more other features, characteristics, steps, operations, elements, components, and/or groups thereof.

The structures and operations discussed below may occur out of the order described and/or noted in the figures. For example, two operations and/or figures shown in succession may in fact be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Similarly, individual operations within example methods described below may be executed repetitively, individually or sequentially, to provide looping or other series of operations aside from single operations described below. It should be presumed that any embodiment or method having features and functionality described below, in any workable combination, falls within the scope of example embodiments.

As used herein, “axial” and “vertical” directions are the same up or down directions oriented along the major axis of a nuclear reactor, often in a direction oriented with gravity. “Transverse” and “horizontal” directions are perpendicular to the “axial” and are side-to-side directions oriented in a single plane at a particular axial height.

The Inventors have recognized that electrical discharge machining, as well as other material removal work, may leave a recast layer or a cold worked layer in the material being machined. This layer presents undesirable traits for interfacing with a cover or other repair, including material roughness and weakness. For machining in remote areas and/or underwater, such as in deep nuclear reactor repairs, it is infeasible to remove this layer with direct or hand tooling. The Inventors have further recognized that shot peening and/or laser treatment remotely may insufficiently remove the recast layer and not impart compression to strengthen and even the material. Lasers and shot peening may also be difficult to achieve in deep remote locations, especially in timely combination. Example embodiments described below uniquely enable solutions to these and other problems discovered by the Inventors.

The present invention is systems for remotely treating surfaces and methods of using the same in nuclear reactor spotfaces. In contrast to the present invention, the few example embodiments and example methods discussed below illustrate just a subset of the variety of different configurations that can be used as and/or in connection with the present invention.

FIG.2is an illustration of an example embodiment bridge assembly100configured to remotely position grinding and/or smoothing elements over a work surface. Although surfaces described in connection with example embodiments include bores and spotfaces deep underwater in reactors, it is understood that example embodiments are useable in connection with any type of surface requiring remote treatment, including pipe interiors, holding tanks or pools, access-restricted areas, etc. As shown inFIG.2, bridge assembly100includes bridge101that may have a “U” shape with body and legs that allow positioning over, or separated from, a surface. Legs of bridge101may secure to or seat against a component having a surface, such as a spotface, to be treated. Anchoring (as shown inFIGS.4A-C) may further be used as a securing device between legs of bridge101and the component. Bridge101may have other shapes and configurations that allow it to better fit to and/or access a surface to be worked.

Example embodiment bridge assembly100includes one or more drives to power various components, such as spindle120rotatable about a working surface. For example, bridge assembly100may include stepper motor110that rotates spindle120about bridge101. Stepper motor110may connect to spindle assembly120via transmission115, which may be a chain that meshes with a gear on spindle120in any desired ratio, such as a 2:1 ratio of rotation between stepper motor110and spindle120. Similarly, a direct drive or any other type of powering may be used to rotate spindle assembly about a work surface. Spindle120may be rotationally seated in a middle of bridge101to permit full rotation of spindle120about a central vertical axis of bridge101.

Motor110, as well as other drives and devices in example embodiments, may be connected to controls, operators, data, and/or power through an umbilical connection105. Alternatively, local power sources and wireless communications can be used to power and control example embodiments. Spindle120may connect to and power and/or control polishing assembly200and/or bore polisher300through connections102and105. For example, connection103may carry a pneumatic line, electrical line, and/or data connection to power bore polisher300, and connection102may carry hydraulic power, electricity, data, etc. to polishing assembly200.

Through all these connections and power arrangements, example embodiment bridge assembly100may be positioned in remote areas, such as far into pipes or deep in flooded reactors, and operate with desired characteristics.

Spindle120connects to desired toolings to work on surfaces under bridge assembly100. For example, as shown inFIG.2, polishing assembly200may be connected to and rotated by spindle120. As shown inFIG.3, polishing assembly200may include a polishing mount211that joins to spindle assembly120and connects a rotatable polishing surface201, pneumatic slides210and hydraulic motor205to spindle120to carry the same. Polishing surface201is rotatable about a transverse or angled axis to polish and remove electrical discharge machining recast from surfaces it impinges. Pneumatic slides210may move motor205and polishing surface201in horizontal and vertical directions as shown inFIG.3, to reach all surfaces in spotface15, for example. Pneumatic slides210may supply a large amount of force directed along the internal rotation axis of polishing surface201. For example, pneumatic slides210may expand between polishing mount211and polishing surface201for up to about 12 lbs. of force per ½-inch of width of the polishing surface. These higher levels of force, such as about 60-70 lbs. of force on a round polishing surface201of 5-6 inches, polish a larger recast layer and are sufficient to both remove the recast material and impart compressive stresses in most metallic surfaces. In a reactor shroud support, for example, this may be sufficient surface layer removal and compression to give a good working surface that it not subject to further degradation in the reactor.

Polishing surface201may be round, up to about 5.5 inches in diameter, for example, and driven angularly by hydraulic motor205, which may have a separate or local power supply. Hydraulic motor205may be a positive displacement motor that can maintain a constant speed in polishing surface201even under heavier polishing pressures. For example, polishing surface201maybe driven at about 50 ft/s or more, or about 2000 rpm. Polishing surface201may use any abrasive of polishing material to achieve a desired surface finish, including, for example, an approximate 80 grit silicon carbide filament surface with about 30-40% grit load by weight. Polishing assembly200may position polishing surface201at approximately 10 degrees to spotface surface14(FIG.1).

FIGS.4A-Care illustrations of example embodiment polishing assembly200carried by example embodiment bridge assembly100in various configurations for polishing surfaces13and14of spotface15, in an example method of preparing a nuclear reactor spotface for repair during a maintenance period. As shown inFIGS.4A-C, bridge101may be mounted on a surface about spotface15, which may be formed by electrical discharge machining. Polishing assembly200extends down into spotface15from spindle assembly120to contact surfaces13and14against polishing surface201.

Polishing surface201may be rotated about its internal axis by hydraulic motor205or another drive in assemblies100and/or200with desired pressure and movement of the same. For example, spindle120may be rotated about its central axis by stepper motor110to, in turn, orbit or revolve polishing assembly200across a perimeter of spotface15. In this way, polishing surface201may move along a continuous and entire spotface surface14and bore surface13, removing a recast layer and compressing the same. Simultaneously, pneumatic slide210may expand to push polishing surface201from polishing support211, providing desired polishing force or pressure.

InFIG.4A, polishing assembly200is oriented vertically and mated with bore polishing wheel301in bore polisher300. Pneumatic slides210(FIG.3) may push assembly200in the vertical direction along axis302(FIG.4B). In this position, polishing wheel301may polish bore surfaces13and14when wheel301is rotated about axis302. InFIG.4B, polishing wheel301is withdrawn lower vertically by pneumatic slides201along axis302to polish vertical sides of surface13. InFIG.4C, polishing assembly200is disconnected from bore polisher300and rotated about several axes to be brought into contact with spotface surface14.

Hydraulic motor205and stepper motor110are of sufficient force to continue driving polishing surface201, which may be rotating at thousands of rotations per minute, at these positions and pressures without being torqued out of position. All drives, including, for example, hydraulic motor205, stepper motor110, pneumatic slides210, etc. may be locally or remotely powered through appropriate connections, and can further be controlled through, and relay data through, umbilical connection105(FIG.2). The continuous surface-to-surface polishing achieved by rotation of polishing surface201, pressure from pneumatic slide210, and feed across surfaces13and14from rotation of spindle120can be achieved through combined operation of these components, removing all recast layer and supplying desired compression forces evenly throughout.

Example embodiment assemblies100and200may be fabricated of materials that are compatible with an operating nuclear reactor environment, including materials that maintain their physical characteristics when exposed to high-temperature fluids and radiation. For example, metals such as stainless steels and iron alloys, nickel alloys, zirconium alloys, etc. are useable in assembly components. Similarly, direct connections between distinct parts and all other direct contact points may be lubricated and fabricated of alternating or otherwise compatible materials to prevent seizing, fouling, or metal-on-metal reactions.

Example embodiments and methods thus being described, it will be appreciated by one skilled in the art that example embodiments may be varied 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 by example embodiment assemblies, simply through proper dimensioning and positioning. Such variations are not to be regarded as departure from the scope of these claims.