CROSS-REFERENCE TO RELATED APPLICATIONS

[0001 ] This application claims priority from U.S. Provisional Patent Application No. 63/404,245, filed on September 7, 2022. The entire contents of U.S. Provisional Patent Application No. 63/404,245 is herein incorporated by reference for all purposes.

FIELD

[0002] This disclosure relates generally to tools and methods for calandria tube sheet removal, more specifically to a tube sheet grip and cut tool for removal of the calandria tube sheet and corresponding method.

INTRODUCTION

[0003] The following is not an admission that anything discussed below is part of the prior art or part of the common general knowledge of a person skilled in the art.

[0004] Given the radiation hazard posed by the calandria and associated components, careful consideration needs to be given when designing systems and method for disassembling and segmenting a calandria. There is need for a tool and corresponding method for removing segments of the tube sheet of the calandria.

SUMMARY OF SOME EMBODIMENTS

[0005] In accordance with a broad aspect, tools and method of segmenting a tube sheet of a calandria are described herein. The tube sheet grip and cut tool for removing a tube sheet segment comprises a body, a rotary tube in rotatable communication with the body, the rotary tube for rotating an extension arm, a cutting head in communication with the extension arm, the cutting head configured to cut the tube sheet segment, and a gripping portion in communication with the body, the gripping portion configured to attach to a tube sheet segment, wherein the rotary tube rotates to allow the cutting head to cut a tube sheet segment.

[0006] In at least one embodiment, the tool further comprises a coupling portion in communication with the body, the coupling portion for attaching the tube sheet grip and cut tool to a mechanism for movement. [0007] In at least one embodiment, the mechanism is deployed from a reactivity deck of a nuclear reactor core.

[0008] In at least one embodiment, the mechanism is a gantry and mast system, a demolition robot, or another type of robot.

[0009] In at least one embodiment, the gripping portion radially extends to grip the tube sheet segment.

[0010] In at least one embodiment, the cutting head is moveable along the extension arm to increase or decrease the size of the tube sheet segment.

[0011 ] In at least one embodiment, the tube sheet grip and cut tool is configured to approach the tube sheet segment for removal, attach to the tube sheet segment by the gripping portion, move the extension arm and the cutting head to cut the tube sheet segment, and remove the tube sheet segment by the gripping portion.

[0012] In at least one embodiment, the tube sheet grip and cut tool is coupled to the mast and gantry system by the coupling portion.

[0013] In at least one embodiment, movement of the tube sheet grip and cut tool is conducted by a processor configured to automatically control the operations thereof.

[0014] In accordance with a broad aspect, a method of cutting and removing a tube sheet segment includes approaching the tube sheet segment for removal with a tube sheet grip and cut tool comprising a body, a rotary tube in rotatable communication with the body, the rotary tube for rotating an extension arm, a cutting head in communication with the extension arm, the cutting head configured to cut the tube sheet segment, and a gripping portion in communication with the body, the gripping portion configured to attach to a tube sheet segment, wherein the rotary tube rotates to allow the cutting head to cut a tube sheet segment. The method further includes attaching, by the gripping portion, the tube sheet grip and cut tool to the tube sheet segment, moving the extension arm and the cutting head, cutting, by the cutting head, the tube sheet segment, and removing the tube sheet segment by the gripping portion. [0015] In at least one embodiment, the tube sheet grip and cut tool further comprises a coupling portion in communication with the body, the coupling portion for attaching the tube sheet grip and cut tool to a mechanism for movement.

[0016] In at least one embodiment, the method includes attaching, by the coupling portion, the tube sheet grip and cut tool to the mast and gantry system prior to approaching the tube sheet segment.

[0017] In at least one embodiment, the movement of the tube sheet grip and cut tool is facilitated by the mast and gantry system.

[0018] In at least one embodiment, the cutting head is moveable along the extension arm to increase or decrease the size of the tube sheet segment.

[0019] In at least one embodiment, movement of the tube sheet grip and cut tool is conducted by a processor configured to automatically control the operations thereof.

[0020] In at least one embodiment, after removal of the tube sheet segment by the gripping portion, the tube sheet segment is deposited in a waste container after removal.

[0021 ] These and other features and advantages of the present application will become apparent from the following detailed description taken together with the accompanying drawings. It should be understood, however, that the detailed description and the specific examples, while indicating preferred embodiments of the application, are given by way of illustration only, since various changes and modifications within the spirit and scope of the application will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] For a better understanding of the described embodiments and to show more clearly how they may be carried into effect, reference will now be made, by way of example, to the accompanying drawings in which:

[0023] FIG. 1 is a perspective view of a calandria of a nuclear reactor core;

[0024] FIG. 2 is a perspective view of mast and gantry system installed at a reactivity deck of the nuclear reactor core;

[0025] FIG. 3 is a perspective view of a tube sheet grip and cut tool; [0026] FIG. 4 is a perspective view of tube sheet grip and cut tool attached to a gantry and mast delivery system; and

[0027] FIG. 5 is a block diagram of a method of segmenting a tube sheet of a calandria, according to at least one embodiment described herein.

DESCRIPTION OF EXAMPLE EMBODIMENTS

[0028] Various apparatuses will be described below to provide an example of one or more embodiments. No embodiment described below limits any claims and any claims may cover apparatuses that differ from those described below. The claims are not limited to apparatuses, methods or systems having all of the features of any one apparatus, method, or system described below or to features common to multiple or all of the apparatuses, methods and systems described below. It is possible that an apparatus, system or method described herein is not an embodiment of any claim. Any embodiment disclosed herein that is not claimed in this document may be the subject matter of another protective instrument, for example, a continuing patent application, and the applicant(s), inventor(s) and/or owner(s) do not intend to abandon, disclaim or dedicate to the public any such embodiment merely by its disclosure in this document.

[0029] Furthermore, it will be appreciated that for simplicity and clarify of illustration, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the example embodiments described herein. However, it will be understood by those of ordinary skill in the art that the example embodiments described herein may be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the example embodiments described herein. Also, the description is not to be considered as limiting the scope of the example embodiments described herein.

[0030] The terms "including", "comprising", and variations thereof mean "including but not limited to", unless expressly specified otherwise. A listing of items does not imply that any or all of the items are mutually exclusive, unless expressly specified otherwise.

The terms "a", "an", and "the" mean "one or more", unless expressly specified otherwise.

[0031 ] As used herein and in the claims, two or more parts are said to be "coupled", "connected", "attached", “mounted” or "fastened" where the parts are joined or operate together either directly or indirectly (i.e. , through one or more intermediate parts), so long as a link occurs. As used herein and in the claims, two or more parts are said to be "directly coupled", "directly connected", "directly attached", or "directly fastened" where the parts are connected in physical contact with each other. As used herein, two or more parts are said to be "rigidly coupled", "rigidly connected", "rigidly attached", or "rigidly fastened" where the parts are coupled so as to move as one while maintaining a constant orientation relative to each other. None of the terms "coupled", "connected", "attached", “mounted”, and "fastened" distinguish the manner in which two or more parts are joined together.

[0032] Some elements herein may be identified by a part number, which is composed of a base number followed by an alphabetical or subscript-numerical suffix (e.g., 112a, or 1121 ). Multiple elements herein may be identified by part numbers that share a base number in common and that differ by their suffixes (e.g., 1121 , 1122, and 1123). Elements with a common base number may in some cases be referred to collectively or generically using the base number without a suffix (e.g., 112).

[0033] It should be noted that terms of degree such as "substantially", "about", and "approximately" as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. These terms of degree may also be construed as including a deviation of the modified term, such as by 1 %, 2%, 5% or 10%, for example, if this deviation does not negate the meaning of the term it modifies.

[0034] It should also be noted that, as used herein, the wording “and/or” is intended to represent an inclusive-or. That is, “X and/or Y” is intended to mean X or Y or both X and Y, for example. As a further example, “X, Y, and/or Z” is intended to mean X or Y or Z or any combination thereof of X, Y, and Z.

[0035] Furthermore, the recitation of numerical ranges by endpoints herein includes all numbers and fractions subsumed within that range (e.g., 1 to 5 includes 1 , 1.5, 2, 2.75, 3, 3.90, 4, and 5). It is also to be understood that all numbers and fractions thereof are presumed to be modified by the term "about" which means a variation of up to a certain amount of the number to which reference is being made if the end result is not significantly changed, such as 1 %, 2%, 5%, or 10%, for example.

[0036] The following description is not intended to limit or define any claimed or as yet unclaimed subject matter. Subject matter that may be claimed may reside in any combination or sub-combination of the elements or process steps disclosed in any part of this document including its claims and figures. Accordingly, it will be appreciated by a person skilled in the art that an apparatus, system or method disclosed in accordance with the teachings herein may embody any one or more of the features contained herein and that the features may be used in any particular combination or sub-combination that is physically feasible and realizable for its intended purpose.

[0037] Disclosed herein are the tools and corresponding methods for the removal of a calandria tube sheet from a nuclear reactor core. Recently, there has been a growing interest in developing new tools and methods for disassembling and segmenting a calandria.

[0038] Referring first to FIG. 1 , shown therein is a perspective view of a nuclear reactor core 100. In the example illustrated, the nuclear reactor core 100 is a CANDll™- type reactor. As illustrated, the nuclear reactor core 100 may include a calandria 102 which is a generally cylindrical vessel that, when in use, contains a heavy-water moderator. The calandria 102 may include a shell 104 which extends longitudinally between a first Calandria tube sheet 106 and a second tube sheet (not shown). In the example illustrated, the nuclear reactor core 100 also includes a first Fueling Machine Tubesheet 108 and a second Fueling Machine Tubesheet (not shown). As shown, the first Fueling Machine Tubesheet108 may be spaced longitudinally outward of the first tube sheet 106 at a first end 110a of the nuclear reactor core 100. The second Fueling Machine Tubesheet may be spaced longitudinally outward of the second tube sheet at a second end 110b of the nuclear reactor core 100.

[0039] Each of the first tube sheet 106 and the first Fueling Machine Tubesheet 108, may include a plurality of lattice sites 112. Each lattice site of the plurality of lattice sites 112 may be used to support a fuel channel assembly or lattice tube 124. [0040] In the example illustrated, the nuclear reactor core 100 also includes plurality of lattice tubes 124. As shown in FIG. 1 , the plurality of lattice tubes 124 may extend between the first tube sheet 106 and the first Fueling Machine Tubesheet 108. In the example illustrated, each lattice tube of the plurality of lattice tubes 124 is welded to one of the first tube sheet 106 and is welded to one of the first Fueling Machine Tubesheet 108.

[0041 ] Referring now to FIG. 2, shown therein is another perspective view of the nuclear reactor core 100. In the example illustrated, a mast and gantry system 116 is positioned on a reactivity deck 118 of the nuclear reactor core 100. Herein, the term reactivity deck 118 is used to refer to an upper portion, or deck, of a concrete casing surrounding calandria 102. In some examples, the reactivity deck 118 supports upper ends of reactivity control units, their mechanisms, shielding, and connecting tubes and cables.

[0042] In the illustrated example, a remote demolition robot 114 is positioned adjacent to calandria 102. The remote demolition robot 114 may be configured to receive, support or use an attachment in the segmentation of calandria 102.

[0043] The mast and gantry system 116 of the nuclear reactor core 100 is used to connect to the tooling used to remove sections of the tube sheet 106 of the calandria 102. Mast head 126 of the mast and gantry system 116 may be the connection point between the mast and gantry system 116 and the tooling used for tube sheet 106 removal.

[0044] The following description outlines the tool and methods for removal of sections of the tube sheet 106 and lattice sites 112 within a nuclear reactor core 100. Although the discussion that follows is in respect of a CANDll™ type nuclear reactor, it is to be understood that the systems and methods described below may be implemented on other types of nuclear reactors.

[0045] In accordance with one aspect of this disclosure, which may be used by itself or in combination with any other aspect of this disclosure, a tube sheet grip and cut tool 150 may be operable to remove a tube sheet 106, lattice sites 112, and/or lattice tubes 124 in a calandria 102 of a nuclear reactor core 100.

[0046] Referring to FIG. 4, the tube sheet grip and cut tool 150 includes a body 151 , a gripping portion 154, a cutting head 156, a rotary tube 164 and an extension arm 158. [0047] The body 151 of the tube sheet grip and cut tool 150 may be cylindrical in shape. This may facilitate the rotation of the rotary tube 164 around the body 151 .

[0048] The rotary tube 164 of the tube sheet grip and cut tool 150 is used to rotate the extension arm 158 and attached cutting head 156 around the body 151 of the tube sheet grip and cut tool 150.

[0049] The gripping portion 154 of the tube sheet grip and cut tool 150 is used to facilitate connection between the tube sheet grip and cut tool 150 and the lattice sites 112 of the tube sheet 106.

[0050] The gripping portion 154, when in use, may be placed within a lattice site 1 12 of the tube sheet 106, where the gripping portion 154 has an initial outside diameter smaller than the inside diameter of the lattice site 112. As such, the gripping portion 154 may be insertable into the lattice site 112 of the tube sheet 106 without contacting the sides of the lattice site 112. In some embodiments, the lattice site 112 of the tube sheet 106 may include a lattice tube 124. In such embodiments, the gripping portion 154 may be insertable into the lattice tube 124 in connection with the lattice site 112 of the tube sheet 106.

[0051 ] Once within the lattice site 112 or the lattice tube 124, the gripping portion 154 may extend radially from the initial diameter to an increased diameter to contact the sides of the lattice site 112 and/or lattice tube 124. The radial extension of the gripping portion 154 may grip the interior surface of the lattice site 112 and/or lattice tube 124, applying pressure to the interior wall of the lattice site 112 and/or lattice tube 124. This may provide the gripping portion 154 with a grip able to hold the tube sheet 106 in place.

[0052] In some embodiments, the gripping portion 154 may use any other type of gripping mechanism, such as hooks, adhesive, magnets, or any other type of mechanism for attachment and movement of a segment of tube sheet 106.

[0053] The cutting head 156 of the tube sheet grip and cut tool 150 is used to cut and release the tube sheet 106 and the corresponding lattice site 112 and/or lattice tube 124.

[0054] The cutting head 156 may be attached to the tube sheet grip and cut tool 150 by an extension arm 158. The extension arm 158 may extend from the body 151 of the tube sheet grip and cut tool 150. [0055] The extension arm 158 may be coupled to the body 151 by a rotary tube 164. The rotary tube 164 may be coupled to the body 151 to facilitate rotation around the body

151 . The rotation of the rotary tube 164 around the body in turn rotates the extension arm 158.

[0056] The extension arm 158 may include a ball screw shaft 160. The ball screw shaft 160 may be attached to the cutting head 156 and configured to allow the cutting head 156 to move from a first position near the gripping portion 154 to an extended position away from the gripping portion 154. This ball screw shaft 160 may allow the cutting head 156 to have an increased reach on the tube sheet 106 to cut and retrieve a larger size segment of the tube sheet 106.

[0057] The cutting head 156 further includes a cutting blade 162 on the distal end of the cutting head 156. The cutting blade 162 may be designed to cut any type of material, such as metal, plastic, etc., or any other type of material. The cutting blade 162 may be used to pierce through the tube sheet 106 and cut a segment of the tube sheet 106.

[0058] In some embodiments, the cutting head 156 may include a plasma torch attached thereto. The plasma torch may be used to cut the tube sheet 106.

[0059] The tube sheet grip and cut tool 150 may further include a coupling portion

152. The coupling portion 152 of the tube sheet grip and cut tool 150 is used to connect the tube sheet grip and cut tool 150 to the mast and gantry system 116. The mast head 126 of the mast and gantry system 116 may connect with coupling portion 152 of the tube sheet grip and cut tool 150. When connected, the mast and gantry system 116 may be operable to move the tube sheet grip and cut tool 150.

[0060] In some embodiments, the coupling portion 152 may be a pin, a bolt, a radially expandable portion, a snap, or any other coupling tool that may attach the tube sheet grip and cut tool 150 to the mast and gantry system 116. In another embodiment, the tube sheet grip and cut tool 150 may be coupled to the mast and gantry system 116 by another method or at another location on the body 151 .

[0061 ] In some embodiments, the tube sheet grip and cut tool 150 may be coupled to any other mechanism for movement. In some embodiments, the tube sheet grip and cut tool 150 may be coupled to the remote demolition robot 114 for segmentation of the Fueling Machine Tubesheet 108. In some embodiments, the tube sheet grip and cut tool 150 may be moveable by, for example, a robot deployed from the reactivity deck.

[0062] A processor may be used to control each of the mast and gantry system 116 and the tube sheet grip and cut tool 150. Accordingly, the processor may be operable to facilitate tube sheet 106 and lattice tube 124 removal with no human interaction with tools within the nuclear reactor core 100.

[0063] The processor may be operable to control the tube sheet grip and cut tool 150, which may include aligning the tube sheet grip and cut tool 150 with the lattice site 112 and/or the lattice tube 124 therein; advancing the tube sheet grip and cut tool 150 into the lattice site 112 and/or lattice tube 124; expanding the gripping portion 154 within the lattice site 112 and/or lattice tube 124; operating the cutting head 156 of the tube sheet grip and cut tool 150 to make the desired cuts; and retracting the tube sheet grip and cut tool 150 and the cut segment of the tube sheet 106.

[0064] In some examples, the processor may include at least one of a SCADA panel, a server, a vault network panels a control equipment area panel, and a RCC network panel. In some examples, the processor may include at least one of Siemens Software, SCADA Application program, SCADA PLC Program, and Illuminate program.

[0065] Referring to FIG. 4, an example of a tube sheet grip and cut tool 150 operating on the tube sheet 106 of a nuclear reactor core 100 is illustrated. As shown, the tube sheet grip and cut tool 150 may be positioned outward of the tube sheet 106 of the nuclear reactor core 100. In the example illustrated, the tube sheet grip and cut tool 150 is mounted to mast head 126 of the mast and gantry system 116.

[0066] In the example illustrated, the gripping portion 154 has been inserted into the lattice site 112 of the tube sheet 106.

[0067] Reference is now made to FIG. 5, which shows a block diagram of a method 200 of segmenting a tube sheet 106 from a calandria 102 of a nuclear reactor core 100 using the tube sheet grip and cut tool 150.

[0068] The steps of the method as described herein may be conducted remotely, by a human operator controlling the operations of the above-described system elements, or autonomously, by a processor configured to automatically control the operations thereof. [0069] At a first step 202 of method 200, tube sheet grip and cut tool 150 is positioned at or adjacent to the tube sheet 106 of calandria 102.

[0070] Optionally, prior to first step 202, the tube sheet grip and cut tool 150 may be attached to the mast and gantry system 116 by the coupling portion 152. The mast and gantry system 116 is configured to receive, support and use the tube sheet grip and cut tool 150 in the segmentation of tube sheet 106.

[0071 ] At first step 202, the mast and gantry system 116 holding the tube sheet grip and cut tool 150 may be positioned at the tube sheet 106 of the calandria 102.

[0072] Continuing with the method 200, at second step 204, the tube sheet grip and cut tool 150 is attached to the tube sheet 106 by the gripping portion 154. Gripping portion 154 may be inserted into a lattice site 112 of the tube sheet 106. In some embodiments, the gripping portion may be inserted into a lattice tube 124 located at a lattice site 112 of the tube sheet 106.

[0073] In at least one embodiment, at step 204, the gripping portion 154 is radially expanded once within the lattice site 112 and/or the lattice tube 124 of the tube sheet 106 to facilitate pressure between the gripping portion 154 and the tube sheet 106 and grip the tube sheet 106.

[0074] Continuing with method 200, at third step 206 and fourth step 208, the extension arm 158 and the cutting head 156 are moved around body 151 of the tube sheet grip and cut tool 150 to cut the tube sheet 106. The movement may be articulated to outline the segmentation of the tube sheet 106.

[0075] The movement of the extension arm 158 and cutting head 156 may include rotation around the body 151 of the tube sheet grip and cut tool 150 by the rotary tube 164. The circular motion may cut the tube sheet 106 in circular or semi-circular shaped pieces, for example. In addition to the rotary motion, the cutting head 156 may be moved along the extension arm 158. The cutting head 156 may be moved to a position close to the body 151 and the gripping portion 154 to cut the tube sheet 106 in smaller pieces, for example. In other embodiments, the cutting head may be moved to a position away from the body 151 and the gripping portion 154 along the extension arm 158 to cut the tube sheet 106 in larger pieces, for example. Further motion of the extension arm 158 and the cutting head 156 may be any combination of the movement described above.

[0076] The movement of the extension arm 158 and the cutting head 156 in step 206 may be simultaneous to the cutting of the tube sheet 106 by the cutting head 156.

[0077] Continuing with method 200, at fifth step 210, the tube sheet 106 portion cut by the cutting head in step 208 is removed from the tube sheet 106. The tube sheet 106 segment remains attached to the tube sheet grip and cut tool 150 by the gripping portion 154.

[0078] In some embodiments, the tube sheet grip and cut tool 150 may transport the tube sheet 106 segment to the reactivity deck 118. The tube sheet 106 segment may then be deposited in any location, such as within a waste container.

[0079] The method 200 may be repeated as many times as desired to remove the required portion of the tube sheet 106.

[0080] While the above description describes features of example embodiments, it will be appreciated that some features and/or functions of the described embodiments are susceptible to modification without departing from the spirit and principles of operation of the described embodiments. For example, the various characteristics which are described by means of the represented embodiments or examples may be selectively combined with each other. Accordingly, what has been described above is intended to be illustrative of the claimed concept and non-limiting. It will be understood by persons skilled in the art that other variants and modifications may be made without departing from the scope of the invention as defined in the claims appended hereto. The scope of the claims should not be limited by the preferred embodiments and examples but should be given the broadest interpretation consistent with the description as a whole.