CA2766596A1 - Fastener shearing tool - Google Patents

Abstract

A tool is provided for separating a feeder coupling from an end-fitting of a CANDU .TM.-type nuclear reactor fuel channel by shearing one or more feeder coupling fasteners.
A gripper has an inside surface and an outside surface. A portion of the inside surface is configured to engage a snout of the end fitting. A pusher is disposed about the gripper. The pusher has a nose portion for contact with the feeder coupling. An actuator controllably acts between the pusher and the gripper to drive the pusher into the feeder coupling to shear the feeder coupling fasteners.

Description

Attorney Docket No. 027813-9027 FASTENER SHEARING TOOL

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to U. S. Provisional Patent Application No.
61/432,976, filed January 14, 2011, the contents of which are herein incorporated by reference.
BACKGROUND

[0002] The present invention relates to tooling for nuclear reactor refurbishment operations.

[0003] More specifically, the invention relates to removal of feeder components from the primary heat transport system of a CANDU-type nuclear reactor. The CANDU
("CANada Deuterium Uranium") reactor is a pressurized heavy-water moderated, fission reactor capable of using fuels composed of natural uranium, other low-enrichment uranium, recycled uranium, mixed oxides, fissile and fertile actinides, and combinations thereof.

SUMMARY

[0004] In some embodiments, the invention provides a tool for separating a feeder coupling from an end-fitting of a CANDU-type nuclear reactor fuel channel by shearing one or more feeder coupling fasteners. A gripper has an inside surface and an outside surface. A portion of the inside surface is configured to engage a snout of the end fitting. A
pusher is disposed about the gripper. The pusher has a nose portion for contact with the feeder coupling. An actuator controllably acts between the pusher and the gripper to drive the pusher into the feeder coupling to shear the feeder coupling fasteners.

[0005] Other embodiments, the invention provides a system for separating a feeder coupling from an end-fitting of a CANDU-type nuclear reactor fuel channel by shearing one or more feeder coupling fasteners. A hydraulic tool assembly includes a gripper having an inside surface and an outside surface. A portion of the inside surface is configured to engage a snout of the end fitting. A plunger is movably disposed within the inside surface of the gripper tube. The plunger has a first portion with a first outside diameter substantially conforming to an inside diameter of the end fitting, and a second portion having a second outside diameter substantially greater than Attorney Docket No. 027813-9027 the inside diameter of the end fitting. The plunger defines a radial shoulder between the first portion and the second portion. The radial shoulder is configured to contact a distal end of the end fitting. A pusher is disposed about the gripper and the plunger. The pusher has a nose portion for engagement with the feeder coupling during shearing operations. A
hydraulic cylinder acts between the pusher and the gripper to drive the pusher into the feeder coupling to shear the feeder coupling fasteners. The system further includes a hydraulic supply, a user input module, and a control module receiving user input signals from the user input module, and transmitting control signals to the hydraulic supply to controllably actuate the hydraulic cylinder.

[0006] In other embodiments, the invention provides a method of separating a feeder coupling from an end-fitting of a CANDU-type nuclear reactor fuel channel. A
gripper is positioned into engagement with a snout of the end fitting. A plunger is inserted into the end fitting, such that a first portion of the plunger with a first outside diameter substantially conforms to an inside diameter of the end fitting and a radial shoulder of the plunger contacts a distal end of the end fitting. A hydraulic fluid is controllably supplied to a hydraulic cylinder. The hydraulic cylinder acts upon the gripper and a pusher to cause relative motion therebetween. A
nose portion of the pusher is engaged with the feeder coupling, thereby shearing a feeder coupling fastener.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] FIG. 1 is a perspective view of a reactor core of a CANDU-type nuclear reactor.

[0008] FIG. 2 is a cutaway view of a CANDU-type nuclear reactor fuel channel.

[0009] FIG. 3 is a front perspective view of a hydraulic tool assembly (HTA) of a feeder coupling disconnect tool.

[0010] FIG. 4 is a rear perspective view of the HTA of FIG. 3.

[0011] FIG. 5 is a front perspective view with a partial section of the HTA.

[0012] FIG. 6 is a perspective view of a typical CANDU style bolted connection of a feeder to an end fitting (EF).

Attorney Docket No. 027813-9027

[0013] FIG. 7 is a cross-sectional view of the HTA, placed above an EF.

[0014] FIG. 8 is a cross-sectional view of the HTA of FIG. 7, lowered over the EF.

[0015] FIG. 9 is a cross-sectional view of the HTA showing a plunger in an advanced position.

[0016] FIG. 10 is a cross-section view of the HTA with a push tube extended into interference with a feeder coupling.

[0017] FIG. 11 is a detailed view of a front portion of the HTA showing a nosepiece, wedges, and alignment pins, with both alignment pins in a retracted position.

[0018] FIG. 12 is a detailed view of the front portion of the HTA showing the nosepiece, wedges and alignment pins, with one pin extended.

[0019] FIG. 13 is a layout of a system control pendant.

[0020] FIG. 14 illustrates installation of a bolt retainer on a CANDU 6-type EF.

[0021] FIG. 15 is a perspective view of a non-CANDU 6 EF with a bolt retention device 13 installed.

[0022] FIG. 16 is a section view of the EF and EF bushing of FIG. 14.

[0023] FIG. 17 is a perspective view of a square catch tray.

[0024] FIG. 18 is an image of the square catch tray installed in an array of EF's.

[0025] FIG. 19 is a perspective view of the square catch tray with support arms.

[0026] FIG. 20 is an image of the square catch tray with support arms installed in an array of EFs.

[0027] FIG. 21 is a perspective view of a profiled catch tray 16.

[0028] FIG. 22 is an image of the profiled catch tray installed in an array of EFs.

Attorney Docket No. 027813-9027

[0029] FIG. 23 is a front perspective view of a powerpack skid.

[0030] FIG. 24 is a rear perspective view of the powerpack skid of FIG. 23.

[0031] FIG. 25 is a perspective view of an A-frame support.

[0032] FIG. 26 is an illustration of feeder coupling removal operations.

[0033] FIG. 27 is an alternative illustration of feeder coupling removal operations.

[0034] FIG. 28 is a block diagram of the FCDT.

DETAILED DESCRIPTION

[0035] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways.

[0036] FIG. 1 is a perspective of a reactor core of a CANDU-type reactor 6.
The reactor core is typically contained within a vault that is sealed with an air lock for radiation control and shielding. A generally cylindrical vessel, known as a calandria 10, contains a heavy-water moderator. The calandria 10 has an annular shell 14 and a tube sheet 18 at a first end 22 and a second end 24. The tube sheets 18 include a plurality of bores that accept a fuel channel assembly 28. As shown in FIG. 1, a number of fuel channel assemblies 28 pass through the tube sheets 18 of calandria 10 from the first end 22 to the second end 24.

[0037] FIG. 2 is a cut-away view of the fuel channel assembly 28. As illustrated in FIG. 2, each fuel channel assembly 28 is surrounded by a calandria tube ("CT") 32. The CT 32 forms a first boundary between the heavy water moderator of the calandria 10 and the fuel bundles or assemblies 40. The CTs 32 are positioned in the bores on the tube sheet 18. A
CT rolled joint insert 34 within each bore is used to secure the CT 32 to the tube sheet 18.

Attorney Docket No. 027813-9027

[0038] A pressure tube ("PT") 36 forms an inner wall of the fuel channel assembly 28. The PT 36 provides a conduit for reactor coolant and the fuel bundles or assemblies 40. The PT 36, for example, generally holds two or more fuel assemblies 40 and acts as a conduit for reactor coolant that passes through each fuel assembly 40. An annulus space 44 is defined by a gap between the PT 36 and the CT 32. The annulus space 44 is normally filled with a circulating gas, such as dry carbon dioxide, helium, nitrogen, air, or mixtures thereof.
The annulus space 44 and gas are part of an annulus gas system. The annulus gas system has two primary functions.
First, a gas boundary between the CT 32 and PT 36 provides thermal insulation between hot reactor coolant and fuel within the PTs 36 and the relatively cool CTs 32.
Second, the annulus gas system provides an indication of a leaking CT 32 or PT 36 via the presence of moisture, deuterium, or both in the annulus gas.

[0039] An annulus spacer or garter spring 48 is disposed between the CT 32 and PT 36. The annulus spacer 48 maintains the gap between the PT 36 and the corresponding CT
32, while allowing the passage of the annulus gas through and around the annulus spacer 48. Maintaining the gap helps ensure safe and efficient long-term operation of the reactor 6.

[0040] As also shown in FIG. 2, an end fitting (EF) 50 is attached around the fuel channel assembly 28 outside of the tube sheet 18 at each end 22, 24. At the front of each end fitting 50 is a closure plug 52. A feeder assembly 54 is coupled to each EF 50. The feeder assemblies 54 feed reactor coolant into or remove reactor coolant from the PTs 36. In particular, for a single fuel channel assembly 28, the feeder assembly 54 on one end of the fuel channel assembly 28 acts as an inlet feeder, and the feeder assembly 54 on the opposite end of the fuel channel assembly 28 acts as an outlet feeder. As shown in FIG. 6, the feeder assemblies 54 are attached to the end fitting 50 via a feeder coupling 56. The feeder coupling 56 is fastened to the end fitting 50 with a four feeder fasteners 57.

[0041] Referring back to FIG. 2, coolant from the inlet feeder flows along a perimeter channel of the end fitting 50 until it reaches a shield plug 58. The shield plug 58 is contained inside the end fitting 50 and provides radiation shielding. The shield plug 58 also includes a number of openings that allow the coolant provided by the inlet feeder to enter an end of a PT
36. A shield plug 58 located within the end fitting 50 at the other end of the fuel channel Attorney Docket No. 027813-9027 assembly 28 includes similar openings that allow coolant passing through the PT 36 to exit the PT 36 and flow to the outlet feeder assembly 54 through a perimeter channel of another end fitting 50 at the opposite face of the reactor 6. As shown in FIG. 1, feeder tubes 59 are connected to the feeder assemblies 54 in order to carry coolant to or away from the reactor 6.

[0042] Returning to FIG. 2, a positioning hardware assembly 60 and bellows 62 are also coupled to each end fitting 50. The bellows 62 allows the fuel channel assemblies 28 to move axially. The positioning hardware assemblies 60 are used to set an end of a fuel channel assembly 28 in either a locked or unlocked position. In a locked position, the end of the fuel channel assembly 28 is held stationary. In an unlocked position, the end of the fuel channel assembly 28 is allowed to move. A tool can be used with the positioning hardware assemblies 60 to switch the position of a particular fuel channel assembly 28.

[0043] The positioning hardware assemblies 60 are also coupled to an end shield 64. The end shields 64 provide additional radiation shielding. Positioned between the tube sheet 18 and the end shield 64 is a lattice sleeve or tube 65. The lattice tube 65 encases the connection between the end fitting 50 and the PT 36 containing the fuel assemblies 40.
Shielding ball bearings 66 and cooling water surround the exterior the lattice tubes 65, which provides additional radiation shielding.

[0044] In a CANDU-type reactor, periodic refurbishment operations may include retubing.
Retubing is the process of removing CTs, PTs, and associated feeder piping from the Calandria, and replacing them with new or refurbished components.

[0045] One portion of the retubing process includes disconnecting each feeder assembly 54 from its corresponding end fitting EF 50. As previously mentioned, the feeder 54 is coupled to the EF 50 at a feeder coupling 56 by multiple fasteners 57, as best illustrated in FIG. 6. As explained in greater detail below, rather than remove each fastener 57 individually, a Feeder Coupling Disconnect Tool (FCDT) applies an axial force to the feeder coupling 56 to break the bolts 57.

[0046] The FCDT is a system including a hydraulic tool assembly (HTA) 68 (FIGS. 3 and 4)), a hydraulic power pack 70 (FIGS. 23 and 24), an optional EF bushing 72 (FIG. 16), a set of Attorney Docket No. 027813-9027 bolt retention devices 74 (FIGS. 14-16), catch trays 76, 78 (FIGS. 17-22), and an overhead support mechanism such as an A-frame support 80 (FIG. 25).

[0047] Referring to FIGS. 14-16, the bolt retention device 74 is installed over the feeder coupling 56 on the target EF 50 to stop the broken bolt heads and other hardware from ejecting.
Multiple bolt retention devices 74 are provided with each FCDT so that uninterrupted tool cycles can continue during the face series.

[0048] FIGS. 17-21 illustrate various catch trays. Referring to FIG. 17, a square catch tray 76 is illustrated. Referring to FIG. 18, the square catch tray 76 can be positioned between rows of EFs 50. The square catch tray 76 is positioned under the EF 50 being worked on to prevent small reactor components from falling. Referring to FIG. 19, a pair of support arms 82 may be used in conjunction with the square catch tray 76. Referring to FIG. 20, the support arms 82 are used to support the square catch tray 76 where no EFs are available for support below the target EF.

[0049] Referring to FIG. 21 a profiled catch tray 78 is used when vertical feeders are near the target EF 50. As illustrated in FIG. 22, the profiled catch tray simply rests on the EFs 50 below the target EF 50.

[0050] As shown in FIG. 15, an EF 50 may have a helical thread-like interface 83 for the closure plug 52 (FIG. 1), which creates difficulty in transmitting the extreme loading generated by the HTA 68 to the EF 50. To facilitate this, if required, the EF bushing 72 is inserted into the EF 50 before the HTA 68 is installed. FIG. 16 illustrates an end-fitting bushing 72 installed in an EF 50. The end-fitting bushing 72 is only used for those CANDU reactors using a helical groove closure plug. For those CANDU reactors having EFs 50 without helical closure grooves, such as are illustrated in FIG. 14, no bushing 72 is used.

[0051] In some embodiments, the HTA 68 applies an axial force to the feeder coupling 56 to break the feeder fasteners 57. The HTA applies sufficient force to break 3/4"
and larger Y"
Inconel 718 bolts. The HTA 68 of the FCDT weighs approximately 1200 - 1300 lbs. In other embodiments, the tool weighs approximately 1100 lbs. Referring to FIG. 3, the HTA 68 is roughly 12" in diameter and 62" long, with two support legs 84 and two handles 86.

Attorney Docket No. 027813-9027

[0052] Referring to FIG. 7, the HTA includes a gripper 88, a pusher 90, a plunger 92, and an actuator, such as a hydraulic cylinder 94.

[0053] The gripper 88 includes a hollow body having an inside surface 98 and an outside surface 102. The inside surface 98 has an inside diameter 104. A portion of the inside surface defines a semi-annular groove 106 configured to engage a snout 108 of the EF
50.

[0054] Referring to FIG. 8, the plunger 92 includes a substantially cylindrical body having a first portion 110 with a first diameter 112 substantially conforming to an inside diameter of the EF 50, and a second portion 114 having a second outside diameter 116 substantially greater than the inside diameter of the EF 50. The second outside diameter 116 substantially conforms to the inside diameter 104 of the gripper 88. The plunger further defines a radial shoulder 118 between the first portion 110 and the second portion 114. The radial shoulder 118 is configured to contact the snout 108 of the EF 50.

[0055] The plunger 92 is coupled to a plunger actuator assembly 120. In the illustrated embodiment, the plunger actuator assembly 120 includes a lead screw 122. The lead screw 122 is rotatably coupled to the gripper 88 and drivingly coupled to the plunger 92. A handle 124, also illustrated in FIGS. 3-4, is fixed to the lead screw 122 for user actuation of the lead screw.
Rotation of the lead screw 122 causes the plunger 92 to advance or retract along a plunger axis 126.

[0056] The pusher 90 includes a substantially cylindrical body 128 with an extended nose portion 130 for contact with the feeder coupling 56. The pusher 90 is disposed about the gripper 88 and plunger 92. In the illustrated embodiment, the pusher is substantially coaxial with the gripper 88 and plunger 92 along the plunger axis 126. The pusher 90 may be fabricated from hardened tool steel. In some embodiments, an anti-friction coating may be applied to all, or portions of, the pusher 90.

[0057] Referring to FIGS. 11 and 12, some embodiments of the pusher 90 include a nose piece 132, and wedges 134 and 136. The nose piece 132 and wedges 134 and 136 are detachably fastened to the pusher nose portion 130 so that they may be removed for replacement or inspection.

Attorney Docket No. 027813-9027

[0058] FIGS. 11 and 12 further illustrate a first and second alignment pin assemblies 138 and 140. Each alignment pin assembly 138 and 140 includes a pin member 142 and a pin actuation handle 144 coupled to the pin member 142. Each pin actuation handle 144 extends through a u-shaped notch 146 defined in the pusher body 128. With the pin actuation handle 144 engaged to a rear portion of the notch 146, as in FIG. 11, the alignment pin member 142 is retracted behind the nose, nosepiece, and wedges. With the pin actuation handle 144 engage to a forward portion of the notch 146, as in FIG. 12, the pin member 142 extends beyond the nose portion 130, nosepiece 132, and wedges 134 and 136.

[0059] Referring to FIGS. 7-10, hydraulic cylinder 94 selectively drives the pusher 90 relative to the gripper 88. In the illustrated embodiment, the hydraulic cylinder 94 is a hollow-piston, double-acting cylinder with a body 148 and a piston 150. The pusher 90 is fixedly coupled to the body 148, while the gripper 88 is fixedly coupled to the piston 150. The hydraulic cylinder 94 may be provided by EnerpacTM or another vendor. In other embodiments, the hydraulic cylinder 94 may be replaced or supplemented by another type of actuator, including a pneumatic piston, gear arrangement, lead screw or other mechanical or electro-mechanical actuating means.

[0060] Referring to FIGS. 23 and 24, the hydraulic cylinder 94 is actuated by hydraulic fluid received from the hydraulic power pack 70 of the FCDT. FIG. 28 is a block diagram of the major components of the hydraulic power pack 70. The hydraulic power pack 70 includes an electric power supply 152, a control module 154, a hydraulic pump 156, and a control valve 158. The electric power supply 152 includes two circuits of 120V, one 15A and one 20A.
The hydraulic power pack 70 may be a modified commercial unit with extra system monitoring sensors added.

[0061] The control module 154 provides control signals to the control valve 158, which controls the flow of hydraulic fluid to the hydraulic cylinder 94. A plunger forward sensor 160, coupled to the plunger 92, provides a control signal to the control module 154 related to a position of the plunger 92 relative to the EF 50. A hydraulic cylinder retracted sensor 162, coupled to the hydraulic cylinder 94, provides a control signal to the control module 154 related to a retracted position of the hydraulic cylinder 94. A hydraulic cylinder maximum stroke sensor 164 provides a control signal to the control module 154 related to a maximum stroke position of Attorney Docket No. 027813-9027 the hydraulic cylinder 94. Each of the sensors 160, 162, and 164, may be, for example, a proximity sensor.

[0062] The control module 154 receives user inputs from a control pendent 166.
FIG. 13 illustrates a configuration of the control pendent 166. The control pendent includes a forward button 168 and a reverse button 170. Pressing the forward button 168 causes the hydraulic cylinder 94 to advance until the maximum stroke sensor 164 indicates that the hydraulic cylinder 94 has fully extended. Pressing the reverse button 170 causes the hydraulic cylinder 94 to retract until the retracted sensor 162 indicates the hydraulic cylinder 94 has fully retracted.

[0063] The action of breaking the four bolts per connection is accomplished through the following steps. As shown in FIG. 7, the HTA 68 is first located over the target EF 50. As shown in FIG. 8, the HTA 68 is next placed on the EF 50, with the semi-annular groove 106 of the gripper 88 engaged to the snout 108. To securely fasten the HTA 68 to the EF 50, the plunger 92 is fully inserted in the EF 50 to strengthen the EF 50 and to lock the HTA 68 onto the EF 50. With the plunger 92 fully inserted into the EF 50, as indicated by the plunger forward sensor 160 (FIG. 28), the HTA 68 is substantially prevented from becoming disconnected from the EF 50.

[0064] With the gripper 88 engaged to the snout 108 and the plunger 92 inserted in the EF, the HTA can still rotate about the plunger axis 126. This degree of freedom is used in aligning the nose portion 130 of the pusher 90 with the feeder coupling 56.

[0065] One alignment pin 142 is extended, as shown in FIG. 12, by moving the alignment pin handle 144 into a forward locked position. The HTA 68 is then rotated about the plunger axis 126, to position the alignment pin against one face of the feeder coupling 56.

[0066] To start the HTA, the hydraulic cylinder 94 must be in its fully retracted position, as indicated by the hydraulic cylinder retracted sensor 162, and the plunger 92 must be fully seated in the EF 50, as indicated by the plunger forward sensor 160. The plunger forward sensor signal satisfies two criteria. First, that the HTA 68 is locked on the EF 50 and cannot be dislodged partway through the cycle. Second, that the plunger 92 stiffens the EF
structure, allowing it to bear the force being applied to break the feeder fasteners 57. If the plunger 92 were not present, Attorney Docket No. 027813-9027 the HTA 68 could pose a danger to the operator and the EF 50 could suffer catastrophic damage.
It is desirable for the EF 50 to remain intact for subsequent refurbishment operations.

[0067] Upon starting the HTA, an automatic cycle ensures that all four feeder fasteners 57 will be sheared with one full stroke of the hydraulic cylinder 94. This action is completed in two stages. The HTA 68 initially applies forces off-center of the feeder coupling 56, causes two fasteners in-line with a point of contact to break first. In this first phase the feeder coupling 56 twists about the EF until it runs out of travel. When the first two feeder fasteners 57 have broken and the feeder coupling 56 is free to twist a bit more, the coupling now makes contact with the nose portion 130 at two points, and exerts all of the force on the two remaining feeder fasteners 57. Once these last two bolts have broken the tool arrives at its maximum stroke, as indicated by the hydraulic cylinder maximum stroke sensor 164, a user is prompted to reverse the hydraulic cylinder 94 to return it to the starting position, as indicated by the hydraulic cylinder retracted sensor 162.

[0068] The HTA 68 is extremely robust and does not require regular maintenance except for the nose piece 132 and wedges 134 and 136 which contact the feeder coupling 56. These components may be checked periodically for damage and replaced if the contact faces have become damaged. In the event of a tool failure, the malfunctioning component can be replaced from spares provided with the FCDT system. Quick disconnects on sensor cables and hydraulic hoses provide for quick changeouts of the HTA 68, the hydraulic power pack 70 or both.

[0069] FIG. 25 is a perspective view of the A-frame support 80 for supporting the HTA 68.
The A-frame 80 is equipped with a hoist 172. A pneumatic cylinder may that isolates the hoist 172 from the excessive vertical loads that occur during operation of the HTA
68.

[0070] Referring to FIGS. 26-27, the HTA 68 and A-frame support 80 are located on a retubing platform (RTP) 176 along with the operation pendants, while the hydraulic power pack 70 are located on the vault floor connected by 75-foot (approximate) cables/hoses.

[0071] Thus, the invention provides, among other things, a tool for use in the refurbishment of nuclear reactors.

Claims (22)

What is claimed is:

1. A tool for separating a feeder coupling from an end-fitting of a CANDU-type nuclear reactor fuel channel by shearing one or more feeder coupling fasteners, the tool comprising:
a gripper having an inside surface and an outside surface, a portion of the inside surface configured to engage a snout of the end fitting;
a pusher disposed about the gripper, the pusher having a nose portion for contact with the feeder coupling; and an actuator controllably acting between the pusher and the gripper to drive the pusher into the feeder coupling to shear the feeder coupling fasteners.

2. The tool of claim 1, further comprising a plunger movablely disposed within the inside surface of the gripper tube, the plunger having a first portion with a first outside diameter substantially conforming to an inside diameter of the end fitting, and a second portion having a second outside diameter substantially greater than the inside diameter of the end fitting, the plunger defining a radial shoulder between the first portion and the second portion, the radial shoulder configured to contact the snout of the end fitting.

3. The tool of claim 2, further comprising an end-fitting bushing between a portion of the end fitting and the plunger.

4. The tool of claim of 2, wherein the plunger defines a plunger axis, and wherein the plunger, the gripper, and the pusher are substantially co-axial.

5. The tool of claim 2, further comprising a plunger actuator for manually extending and retracting the plunger.

6. The tool of claim 2, wherein the plunger actuator includes a lead screw and an operator handle.

7. The tool of claim 2, further comprising a plunger position sensor for detecting a position of the plunger relative to the end fitting.

8. The tool of claim 1, wherein the actuator includes a hydraulic cylinder.

9. The tool of claim 1, further comprising a replaceable nosepiece detachably coupled to the nose portion.

10. The tool of claim 1, further comprising an alignment pin assembly coupled to the pusher, the alignment pin assembly being selectively positionable between an extended position, in which a leading surface of an alignment pin extends beyond the nose, and a retracted position, in which, the leading surface of the alignment pin is located behind the nose.

11. The tool of claim 3, wherein the alignment pin assembly is a first alignment pin assembly, and wherein the tool further comprises a second alignment pin assembly coupled to the pusher.

12. A system for separating a feeder coupling from an end-fitting of a CANDU-type nuclear reactor fuel channel by shearing one or more feeder coupling fasteners, the system comprising:
a hydraulic tool assembly including a gripper having an inside surface and an outside surface, a portion of the inside surface defining a semi-annular groove configured to engage a snout of the end fitting, a plunger movably disposed within the inside surface of the gripper tube, the plunger having a first portion with a first outside diameter substantially conforming to an inside diameter of the end fitting, and a second portion having a second outside diameter substantially greater than the inside diameter of the end fitting, the plunger defining a radial shoulder between the first portion and the second portion, the radial shoulder configured to contact a distal end of the end fitting, a pusher disposed about the gripper and the plunger, the pusher having a nose portion engageable with the feeder coupling during shearing operations, and a hydraulic cylinder acting between the pusher and the gripper to drive the pusher into the feeder coupling to shear the feeder coupling fasteners;
a hydraulic supply;

a user input module; and a control module receiving user input signals from the user input module, and transmitting control signals to the hydraulic supply to controllably actuate the hydraulic cylinder.

13. The system of claim 12, further comprising a plunger position sensor for detecting a proximity of the plunger to the end fitting and generating a plunger proximity signal received by the control module.

14. The system of claim 13, wherein the plunger proximity signal is a control condition for actuation of the hydraulic cylinder.

15. The system of claim 12, further comprising a hydraulic cylinder position sensor.

16. The tool of claim of 12, wherein the plunger defines a plunger axis, and wherein the plunger, the gripper tube, and the push tube are substantially co-axial.

17. A method of separating a feeder coupling from an end-fitting of a CANDU-type nuclear reactor fuel channel, the method comprising:
positioning a gripper into engagement with a snout of the end fitting, inserting a plunger into the end fitting, such that a first portion of the plunger with a first outside diameter substantially conforms to an inside diameter of the end fitting and a radial shoulder of the plunger contacts a distal end of the end fitting;
controllably supplying a hydraulic fluid to a hydraulic cylinder, the hydraulic cylinder acting upon the gripper and a pusher to cause relative motion therebetween;
engaging a nose portion of the pusher with the feeder coupling; and shearing a feeder coupling fastener.

18. The method of claim 17, wherein the act of positioning includes lowering a portion of the gripper upon the snout of the end fitting.

19. The method of claim 18, wherein the act of lowering a portion of the gripper upon the snout includes engaging a semi-annular groove defined by an inside surface of the gripper with the snout.

20. The method of claim 17, further comprising coupling a catch tray to the feeder coupling.

21. The method of claim 17, wherein the act of shearing the feeder coupling fastener includes shearing four feeder coupling fasteners with a single stroke of the hydraulic cylinder.

22. The method of claim 17, further comprising determining a position of the plunger relative to the end fitting.