CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from U.S. Provisional Patent Application No. 63/403,917, filed on September s, 2022. The entire contents of U.S. Provisional Patent Application No. 63/403,917 is herein incorporated by reference for all purposes.

FIELD

[0002] This disclosure relates generally to cutting tools, and more specifically, to cutting tools for segmenting an embedment ring of a calandria nuclear reactor.

BACKGROUND

[0003] A CANDU (Canada Deuterium Uranium) reactor assembly includes a horizontal cylindrical tank known as a calandria. The calandria typically has about 380 to 480 horizontal fuel channels aligned with an axis of the calandria. The calandria typically also has both vertical and horizontal reactivity control mechanisms oriented perpendicular to the axes of the calandria and fuel channels.

[0004] Decommissioning CANDU reactors necessitates disassembling and/or segmenting the existing calandria, including the embedment ring of a calandria. Given the radiation hazard posed by the calandria and associated components, careful consideration needs to be given when designing systems and methods for disassembling and segmenting a calandria.

[0005] Accordingly, there is a need for improved cutting tools, and particularly for improved cutting tools for segmenting a calandria embedment ring.

SUMMARY

[0006] In accordance with a broad aspect, a cutting tool is described herein. The cutting tool includes a main body having a first end and a second end spaced apart from the first end along a longitudinal axis of the main body; a coupling mechanism positioned at the first end for attaching the cutting tool to a robot; a gripping mechanism comprising a pair of clamps mounted to the main body towards the second end, each of the clamps being configured to grip the embedment ring; and a cutting assembly configured to slide relative to the main body along the longitudinal axis. The cutting assembly includes: a frame: a cuttino element supported on the frame; and a plurality of spindles mounted to the frame and configured to support the cutting element and guide rotation of the cutting element to segment the embedment ring.

[0007] In at least one embodiment, the pair of clamps are movable between a gripping position and a release position to grip the embedment ring.

[0008] In at least one embodiment, the gripping mechanism further comprises a pair of hydraulic cylinders mounted to the main body towards the second end, each of the hydraulic cylinders being configured to move one of the pair of clamps between the gripping position and the release position.

[0009] In at least one embodiment, each of the pair of hydraulic cylinders is mounted to a side of the main body opposed to the cutting assembly.

[0010] In at least one embodiment, each of the hydraulic cylinders moves one of the pair of clamps in a direction transverse to a longitudinal axis of the main body.

[0011] In at least one embodiment, each of the hydraulic cylinders moves one of the pair of clamps in a direction orthogonal to a longitudinal axis of the main body.

[0012] In at least one embodiment, each of the hydraulic cylinders moves one of the pair of clamps in a direction directly towards the other one of the pair of clamps.

[0013] In at least one embodiment, the cutting assembly further comprises a motor mounted to the main body towards the first end of the main body to control movement of the cutting assembly relative to the main body.

[0014] In at least one embodiment, the cutting assembly further comprises a ball screw shaft extending between the motor and the frame of the cutting assembly, the motor being configured to rotate the ball screw shaft to move the cutting assembly in a direction along the longitudinal axis of the main body between a retracted position and an extended position.

[0015] In at least one embodiment, the tool also includes a pair of rails mounted to the main body and extending in a direction along the longitudinal axis and a pair of guides mounted to the frame of the cutting assembly, each of the rails being configured to engage one of the pair of guides to direct the sliding of the cutting assembly.

[0016] In at least one embodiment, each of the pair of rails is positioned on an upper surface of the main body. [0017] In at least one embodiment, each of the pair of guides is mounted to an underside of the frame of the cutting assembly.

[0018] In at least one embodiment, the main body includes a first main body arm and a second main body arm each positioned towards the second end of the main body, the first main body arm and the second main body arm being spaced apart from each other in a direction transverse to the longitudinal axis of the main body to define a main body opening therebetween.

[0019] In at least one embodiment, the frame of the cutting assembly includes a first cutting frame arm and a second cutting frame arm each positioned towards the second end of the main body, the first cutting frame arm and the second cutting frame arm being spaced apart from each other in a direction transverse to the longitudinal axis of the main body to define a cutting frame opening therebetween.

[0020] In at least one embodiment, the main body opening and the cutting frame opening have a same width, the width being greater than a width of the embedment ring.

[0021] In at least one embodiment, the cutting element is a diamond wire that extends across the cutting frame opening in a direction that is transverse to the longitudinal axis of the main body.

[0022] In at least one embodiment, one of the spindles of the cutting assembly is configured to rotate the diamond wire about the plurality of spindles to segment the embedment ring.

[0023] In accordance with another broad aspect, a method of segmenting an object is described herein. The method includes activating a cutting element of a cutting assembly of a cutting tool, the cutting element being configured to move relative to a frame of the cutting assembly, the cutting element being supported on the frame of the cutting assembly, the frame of the cutting assembly being slidingly coupled to a main body of the cutting tool; controlling movement of the cutting tool to position a first main body arm of the tool and a second main body arm of the tool around opposed sides of the object; and as the cutting element is activated, controlling movement of the cutting assembly to slide relative to the main frame to engage the object with the cutting element to segment the object. [0024] In at least one embodiment, the object is an embedment ring of a calandria nuclear reactor.

[0025] 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

[0026] For a better understanding of the various embodiments described herein, and to show more clearly how these various embodiments may be carried into effect, reference will be made, by way of example, to the accompanying drawings which show at least one example embodiment, and which are now described. The drawings are not intended to limit the scope of the teachings described herein.

[0027] FIG. 1 is a perspective view of a remote demolition robot positioned at a reactor face of a calandria, and further showing a gantry and mast delivery system installed at the reactivity deck.

[0028] FIG. 2 is a perspective view of a cutting tool for segmenting an embedment ring of a calandria nuclear reactor, according to at least one embodiment described herein.

[0029] FIG. 3 is an exploded view of the cutting tool of FIG. 1 .

[0030] FIG. 4 is a bottom view of the cutting tool of FIG. 1 .

[0031 ] FIG. 5 is a first side view of the cutting tool of FIG 1 .

[0032] FIG. 6 is a rear view of the cutting tool of FIG. 1 .

[0033] Further aspects and features of the example embodiments described herein will appear from the following description taken together with the accompanying drawings. DESCRIPTION OF VARIOUS EMBODIMENTS

[0034] Various systems, devices and methods are described below to provide an example of at least one embodiment of the claimed subject matter. No embodiment described below limits any claimed subject matter and any claimed subject matter may cover systems, devices and methods that differ from those described below. The claimed subject matter are not limited to systems, devices and methods having all of the features of any one systems, device or method described below or to features common to multiple or all of the systems, devices and methods described below. It is possible that a system, device or method described below is not an embodiment of any claimed subject matter. Any subject matter that is disclosed in a system, device or method described 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 invention by its disclosure in this document.

[0035] Furthermore, it will be appreciated that for simplicity and clarity 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.

[0036] 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 should be construed as including a deviation of the modified term, such as 1 %, 2%, 5%, or 10%, for example, if this deviation does not negate the meaning of the term it modifies.

[0037] As used herein and in the claims, two or more parts are said to be “coupled”, “connected”, “attached”, “joined”, “affixed”, 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”, “directly joined”, “directly affixed”, 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”, “rigidly joined”, “rigidly affixed”, 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”, “joined”, “affixed”, and “fastened” distinguish the manner in which two or more parts are joined together.

[0038] Furthermore, the recitation of any 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 up to a certain amount of the number to which reference is being made, such as 1 %, 2%, 5%, or 10%, for example, if the end result is not significantly changed.

[0039] 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.

[0040] Recently, there has been a growing interest in developing new systems, tools and methods for disassembling a calandria.

[0041] Reference is now made to FIG. 1 , which shows a perspective view of a disassembly and segmentation system interacting with a nuclear reactor core.

[0042] In the illustrated example, the nuclear reactor core 10 is a CANDU-type reactor. The nuclear reactor core 10 includes a calandria 20 that is a generally cylindrical vessel that, when in use, contains a heavy-water moderator. Calandria 20 includes a shell 22 that extends longitudinally between a first reactor face 24 and a second reactor face (not shown).

[0043] As shown, the disassembly and segmentation system includes a gantry and mast system 30. Gantry and mast system 30 is positioned on a reactivity deck 32 of the nuclear reactor core. The gantry and mast system 30 is positioned to disassemble the nuclear reactor from the top, in order to reach the calandria 20. To this end, the gantry and mast system 30 can retain various disassembly and segmentation tools. In other examples, rather than a gantry and mast system - an existing crane can also be used to remove reactivity deck components from reactivity deck 32.

[0044] As used herein, the term “reactivity deck” refers to an upper portion, or deck, of a concrete casing surrounding calandria 20. In some examples, reactivity deck 20 supports upper ends of reactivity control units, their mechanisms, shielding, and connecting tubes and cables.

[0045] The disassembly and segmentation system can also include a remote demolition robot 40, such as but not limited to a Brokk 900 Rotoboom™ demolition robot. The remote demolition robot 40 can receive, support and use one or more attachments in the disassembly and segmentation of the calandria 20. The demolition robot 40 is typically positioned at, or adjacent, first reactor face 24 or the second reactor face, or both. The term “reactor face” herein refers to a face of the calandria 20 where fuel channels, or more specifically end fittings, protrude outwardly from a body, or shell of the calandria 20.

[0046] The final phase of disassembly is to remove the embedment rings 50, end shields and the concrete calandria vault. Calandria 20 is supported within a concrete calandria vault by end shield supports. Each end shield support is provided with an integral embedment ring 50 for direct concreting into the calandria vault end walls. The calandria vault is typically a reinforced concrete structure supported on reinforced concrete bearing foundation walls. The inner surface of the vault may be lined with carbon steel to provide a leak-tight seal for containment of a shield cooling system having demineralized light water. The end shield support includes a stainless steel support shell and an annular support plate combination that is welded to a carbon steel embedment ring. Each embedment ring consists of a cylindrical shell and annular ring elements that may be stiffened by radial gussets at regular intervals around the circumference.

[0047] Recently, there has been growing interest in developing new tools appropriate for cutting the carbon steel, reinforcing concrete and other reinforcing materials that comprise the embedment ring supporting a calandria 20 of a CANDU- type reactor.

[0048] Reference is now made to FIG. 2, which shows a perspective view of a cutting tool 100 for segmenting an embedment ring 50 of a calandria 20 of a CANDU- type nuclear reactor. The cutting tool 100 includes a main body 102. Main body 102 has a first end 104 and a second end 106 spaced from the first end 104 along a longitudinal axis 108 of the main body 102.

[0049] Main tool 102 includes a coupling mechanism 112. In the embodiment shown in the drawings, coupling mechanism 112 is positioned at the first end 104 of the main body 102. The coupling mechanism 112 provides for the cutting tool 100 to be attached to and controlled by a remote demolition robot 40. It should be understood that coupling mechanism 112 may be any coupling mechanism appropriate for communicatively connecting a remote demolition robot 40 to cutting tool 100.

[0050] In the embodiment shown in the drawings, coupling 112 includes an engagement plate 114. Engagement plate 114 facilitates removable coupling between the tool 100 and remote demolition robot 40. Coupling mechanism 112 is positioned on an end of tool 100 opposed to opening 110 (described further below) to provide for the remote demolition robot positioned at first reactor face 24 to maneuver the cutting 100 in a direction towards the engagement ring 50 to cut portions of the engagement ring 50.

[0051 ] Engagement plate 114 may include one or more cavity holes 116, which mechanically couple a distal end of the remote demolition robot 40 to the tool 100 (e.g., via fasteners). In some examples, some of the cavity holes 116 can also receive electrical connections. The electrical connections can enable remote control of various features of the tool 100. For instance, this includes remote control movement of the cutting assembly 124, cutting element 128 and/or the gripping mechanism 118. For instance, the electrical connections may pass from the remote demolition robot 40 into the tool 100. [0052] Main body 112 includes a first main body arm 121 and a second main body arm 123 each positioned towards the second end 106 of main body 102. First main body arm 121 and second main body arm 123 are spaced apart from each other in a direction transverse to the longitudinal axis 108 of the main body 102 by a distance 125. Together with a central member 127 of the main body 102, first main body arm 121 and second main body arm 123 define a main body opening 110. Opening 110 provides for the portion of the main body 102 defined by first main body arm 121 and second main body arm 123 to partially surround a portion of the embedment ring 50, for example to support the portion of the embedment ring 50 as it is being cut.

[0053] Referring now to FIG. 3, in the embodiment shown in the drawings, main body 102 includes a gripping mechanism 118 including a pair of clamps 120 mounted towards the second end 106 of the main body 102. For example, each of the clamps 120 may be mounted to one of the first main body arm 121 and second main body arm 123. Clamps 120 are movable relative to the main body 102 between a gripping position and a release position. In the gripping position, claims 120 extend inwardly into opening 110 to grip the portion of the embedment ring 50 adjacent to a cut line. In the release position, clamps 120 are retracted out of, or away from a center of, opening 110. While in the gripping position, the pair of clamps 120 may provide for the cutting tool 100 to grip and/or support the portion of the embedment ring 50 being cut to, for example, continue gripping a segment of the embedment ring after it has been cut away from a portion of the embedment ring 50 remaining attached to the calandria 20, so as to inhibit the portion of the embedment ring 50 from falling downwardly after it has been cut. Alternatively, the pair of clamps 120 may provide for the cutting tool 100 to grip a portion of the embedment ring adjacent to a cut line, for example, to encourage the portion of the embedment ring 50 being cut to fall downwards. Gripping the embedment ring 50 during cutting may also reduce any impact of vibrations of the embedment ring 50 on cutting tool 100 during cutting.

[0054] Turning to FIG. 4, gripping mechanism 118 may include a pair of hydraulic cylinders 122 mounted to the main body 102 (e.g., one each to first main body arm 121 and second main body arm 123) towards the second end 106. Each of the hydraulic cylinders 122 is configured to move one of the pair of clamps 120 between the gripping position and the release position. Hydraulic cylinders 122 may be each mounted to a side of the main body 102 opposed to the cutting assembly 124, such as to underside 129, to not inhibit movement of the cutting assembly 124 relative to the main body 102. This may also protect the hydraulic cylinders 122 from being damaged during cutting. In at least one embodiment, hydraulic cylinders 122 move the clamps 120 laterally (i.e. , in a direction transverse and/or orthogonal) relative to the longitudinal axis 108 of the main body 102. In at least one embodiment, each of the hydraulic cylinders 122 moves a respective one of the clamps 120 laterally in a direction directly towards the other one of the clamps 120.

[0055] Returning to FIGs. 2 and 3, cutting tool 100 also includes a cutting assembly 124 slidingly coupled to the main body 102.

[0056] Cutting assembly 124 includes a frame 126 slidingly mounted to an upper side 131 of main body 102. Frame 126 is generally U-shaped and includes a first cutting frame arm 135 and a second frame arm 137, each of the first cutting frame arm 135 and second frame arm 137 being positioned towards the second end 106 of main body 102. First cutting frame arm 135 and second cutting frame arm 137 are spaced apart from each other in a direction transverse to the longitudinal axis 108 of the main body 102 by a distance 139. Together with a central member 141 of the frame 126, first cutting frame arm 135 and second cutting frame arm 137 define a cutting frame opening 143. Cutting frame opening 143 provides for the portion of the frame 126 defined by first cutting frame arm 135 and second cutting frame arm 137 to partially surround a portion of the embedment ring 50 during cutting. For example, typically, frame 126 is positioned, prior to cutting the embedment ring 50, such that first cutting frame arm 135 and second cutting frame arm 137 are positioned on either side of the embedment ring 50. After activation of the cutting element 128 (described in greater detail below), frame 126 can be controlled to move from its retracted position to its extended position. In the extended position, first cutting frame arm 135 and second cutting frame arm 137 will have travelled in a direction along the longitudinal axis 108 of main body 102 to cut the embedment ring and the portion of the embedment ring that has been cut will be at least partially positioned between the first cutting frame arm 135 and second cutting frame arm 137 within cutting frame cavity 143.

[0057] In the example shown in the drawings, main body opening 125 and cutting frame opening 143 have a same size and a same shape, however, it should be understood that main body opening 125 and cutting frame opening 143 are not limited to having a same size and a same shape.

[0058] The cutting assembly 124 also includes a cutting element 128 and a plurality of spindles 130 mounted to the frame 126. In the embodiment shown in the drawings, the cutting element 128 is a diamond wire 128. Cutting element 128 extends across opening 110 of the main body and opening 143 of the cutting frame where it engages with the portion of the embedment ring 50 being cut.

[0059] The plurality of spindles 130 are configured to rotate and guide the diamond wire 128 as the diamond wire 128 cuts the embedment ring. In at least one embodiment, at least one of the plurality of spindles 130 is configured to rotate the diamond wire 128. When the diamond wire 128 rotates at a high speed, it is able to cut through the embedment ring 50. For example, the linear speed of the diamond wire 128 may be in a range of about 1 m/s to about 100 m/s, or in a range of about 20 m/s to about 50 m/s, or be greater than about 20 m/s, or be less than about 50 m/s.

[0060] In at least one embodiment, at least one of the plurality of spindles 130 may have a position that is adjustable relative to the frame 126, thereby allowing a tension in the diamond wire 128 to be controlled.

[0061] The cutting assembly 124 is configured to slide relative to the main body 102 in a direction along the longitudinal axis 108. It should be understood that any means known in the art for moving the cutting assembly 124 relative to the main body 102 may be used. In the example shown in the drawings, a motor 132 is mounted to the main body 102 towards the first end 104 and a ball screw shaft 134 extends between the motor 132 and the frame 126 of the cutting assembly 124. The motor 132 rotates the ball screw shaft 134 to move the cutting assembly 124 along the longitudinal axis 108.

[0062] The sliding of the cutting assembly 124 relative to main body 102 is assisted by a pair of rails 136 on an upper surface 138 of the main body 102. The rails 136 extend in the direction of the longitudinal axis 108. Referring to FIG. 5, the frame 126 of the cutting assembly 124 has a pair of guides 140 mounted to an underside 142 of the frame 126. Referring to FIG. 6, the guides 140 interlock with the rails 136, allowing for the movement of the cutting assembly 124 along the rails 136. [0063] While the applicant's teachings described herein are in conjunction with various embodiments for illustrative purposes, it is not intended that the applicant's teachings be limited to such embodiments as the embodiments described herein are intended to be examples. On the contrary, the applicant's teachings described and illustrated herein encompass various alternatives, modifications, and equivalents, without departing from the embodiments described herein, the general scope of which is defined in the appended claims.