CA2766470C - Nuclear reactor feeder removal process - Google Patents

Abstract

A method of removing feeders from a nuclear reactor includes removing at least a portion of a feeder cabinet that can include a feeder cabinet wall and a feeder cabinet soffit, followed by disconnection and removal of feeders used to supply and remove coolant from fuel channel assemblies of the reactor.

Description

Attorney Docket No. 027813-9028 NUCLEAR REACTOR FEEDER REMOVAL PROCESS
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority to U. S. Provisional Patent Application No.
61/433,058, filed January 14, 2011.
BACKGROUND

[0002] The present invention relates to refurbishment of nuclear reactor systems.

[0003] More specifically, the invention relates to removal of feeder components from the primary heat transport system of a CANDUTm-type nuclear reactor. The CANDUTM
(''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.
However, it will be appreciated that invention is not limited in its applicability to CANDU'-type nuclear reactors, and that the invention can be practiced in connection with any other nuclear reactor having the same or similar reactor structures disclosed herein.
SUMMARY

[0004] In some embodiments, the invention provides a method of removing feeders from a CANDUTm-type nuclear reactor plant, including removing at least a portion of a first feeder cabinet, at least a portion of a first feeder cabinet soffit, and at least a portion of a second feeder cabinet soffit, disconnecting at least one feeder coupling, and cutting and removing the corresponding feeder of the coupling.

[0005] In other embodiments, the invention provides a method of removing feeders from a CANDU'-type nuclear reactor plant, wherein the method includes installing a first feeder platform, installing a second feeder platform, and installing a retubing platform.

Attorney Docket No. 027813-9028 BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIG. 1 is a perspective view of a reactor core of a CANDU'-type nuclear reactor.

[0007] FIG. 2 is a cutaway view of a CANDU'-type nuclear reactor fuel channel.

[0008] FIG. 3 is a flow chart illustrating a process for feeder and feeder cabinet removal according to some embodiments of the present invention.

[0009] FIG. 4 is a front view of a CANDUTM feeder cabinet.

[0010] FIG. 5 is a side view of the CANDUTM feeder cabinet illustrated in FIG. 4.

[0011] FIG. 6 is a perspective view of a hoist well, crane and upper feeder monorail disposed adjacent the feeder cabinet shown in FIGs 4 and 5.

[0012] FIG. 7 is a perspective view of the upper feeder monorail of FIG. 6.

[0013] FIG. 8 is a perspective view of portions of a first feeder cabinet being removed with the assistance of scissor lifts.
100141 FIG. 9 is a perspective view of a first feeder platform in place to remove the first soffit of the feeder cabinet [0015] FIG. 10 is a side view of a second feeder platform in place to remove a second upper feeder cabinet and soffit.
[0016] FIG. 11 is a perspective view illustrating lower feeder removal cutting with from scissor lifts, along with work from a retubing-platform (RIP).
DETAILED DESCRIPTION
[0017] 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 ' Attorney Docket No. 027813-9028 accompanying drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways.
[0018] 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 each include a plurality of bores that each 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 the calandria 10 from the first end 22 to the second end 24 of the calandria 10.
[0019] As in the illustrated embodiment, in some embodiments the reactor core is provided with two walls at each end 22, 24 of the reactor core: an inner wall defined by the tube sheet 18 at each end 22, 24 of the reactor core, and an outer wall 64 (often referred to as a "end shield") located a distance outboard from the tube sheet 18 at each end 22, 24 of the reactor core. A
lattice tube 65 spans the distance between the tube sheet 18 and the end shield 64 at each pair of apertures (i.e., in the tube sheet 18 and the end shield 64, respectively).
[0020] FIG. 2 is a cut away view of the fuel channel assembly 28. As illustrated in FIG. 2, each fuel channel assembly 28 includes a calandria tube ("CT") 32 surrounding other components of the fuel channel assembly 28. The CTs 32 each span the distance between the tube sheets 18. Also, the opposite ends of each CT 32 are received within and sealed to respective apertures in the tube sheets 18. In some embodiments, a CT rolled joint insert 34 is used to secure the CT 32 to the tube sheet 18 within the bores, although other tube-to-sheet joining structures and methods can instead be used. In this manner, the CTs 32 each form a first boundary between the heavy water moderator of the calandria 10 and the interior of the fuel channels assemblies 28.
[0021] 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 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 Attorney Docket No. 027813-9028 each PT 36 and its corresponding 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 typically having at least one of 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 indication of a leaking calandria tube 32 or pressure tube 36 via the presence of moisture, deuterium, or both detected in the annulus gas.
[0022] 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 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.
[0023] As also shown in FIG. 2, each end of each fuel channel assembly 28 is provided with an end fitting 50 located outside of the corresponding tube sheet 18. At the terminal end of each end fitting 50 is a closure plug 52. Each end fitting 50 also includes a feeder assembly 54. 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. 2, the feeder assemblies 54 can be attached to the end fittings 50 using a coupling assembly 56 including a number of screws, washers, seals, and/or other types of connectors.
[0024] The lattice tube 65 (described above) 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.
[0025] With continued reference to FIG. 2, coolant from the inlet feeder assembly 54 flows along a perimeter channel of the end fitting 50 until it reaches a shield plug 58. The shield plug 58 is contained within the PT 36 and the lattice tube 65, and includes a number of openings that allow the coolant provided by the inlet feeder assembly to enter the end of the PT 36. Another shield plug 58 is located within the PT 36 and the lattice tube 65 at the other end of the fuel channel assembly 28, and includes similar openings that allow coolant passing through the PT 36 Attorney Docket No. 027813-9028 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 that carry coolant to or away from the reactor 6.
[0026] 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 ¨ a capability that can be important where fuel channel assemblies 28 experience changes in length over time, which is common in many reactors. The positioning hardware assemblies 60 can be used to set an end of a fuel channel assembly 28 in either a locked or an unlocked position. In the locked position, the end of the fuel channel assembly 28 is fixed in an axial position. In the unlocked position, the end of the fuel channel assembly 28 is allowed to move axially. A tool can be used with the positioning hardware assemblies 60 to switch the position of a particular fuel channel assembly 28.
[0027] The positioning hardware assemblies 60 are also coupled to the end shield 64. The positioning hardware assemblies 60 each include a rod having an end that is received in a bore of the respective end shield 64. In some embodiments, the rod end and the bore in the end shield 64 are threaded.
100281 A number of preliminary steps must often be taken to perform refurbishment and retubing operations of a CANDUTm-type heavy water fission reactor (or more broadly, for many other types of nuclear reactors). In the context of CANDUTm-type reactors, retubing is the process of removing calandria tubes, pressure tubes, and associated feeder piping from a CANDU'-type nuclear reactor, and replacing them with new or refurbished components. Some of the preliminary steps in re-tubing operations involve important and innovative manners of preparing a reactor for such re-tubing operations, many of which can enable a re-tubing team significant time and costs over the course of such operations.
[0029] FIG. 3 is a flowchart illustrating an overview of a feeder and feeder cabinet removal method according to some embodiments of the present invention. The feeder and feeder cabinet removal method may be generally described with reference to FIG. 3 as follows, with many of the steps in the process described in greater detail below.

Attorney Docket No. 027813-9028 [0030] A first (e.g., front) feeder cabinet wall is removed using, for example, a scissor lift.
An example of a first feeder cabinet wall is indicated with reference numeral 70 in FIG. 5. Next, a first (e.g. front) feeder platform is installed, an example of which is indicated at 81 in FIGs. 9 and 10. From the first feeder platform, a first (e.g., front) feeder cabinet soffit is removed, an example of which is the approximate right half of the soffit 72 shown in FIG.
5. Next, the first feeder platform is raised above a vault crane 83 and a second (e.g., rear) feeder platform is installed, an example of which is indicated at 82 in FIG. 10. From the second feeder platform, a second (e.g. rear) feeder cabinet soffit is removed, an example of which is the approximate left half of the soffit 72 shown in FIG. 5. Next, the second feeder platform is raised above the vault crane 83, and a retubing platform (RTP) is assembled by first installing RTP
columns and then installing a vertically-adjustable platform thereon. An example of an RTP is shown in FIGs. 4 and 11 at 98 (not shown in FIGs. 8-10). From the RTP, positioning hardware assemblies 60 and closure plugs 52 are removed from each of the fuel channel assemblies 28 (see FIG. 2), and the couplings connecting the feeder assemblies 54 to the fuel channel assemblies 28 are disconnected. The first feeder platform is then lowered to a position at which lower feeders (i.e., connecting to lower fuel channel assemblies 28 on the reactor face) are cut and removed from the RTP, the first feeder platform, and scissor lifts. Examples of lower feeders to be cut are shown at 90 in FIG. 9. Using the RTP and scissor lifts, back wall insulation and cantilever supports are then removed. An example of a back wall of the cabinet is indicated at 78 in FIG. 5, whereas an example of a cantilevered support (extending away from the calandria 10 and used for supporting the lower feeders 90 described in greater detail below) is shown at 94 in FIG. 9.
The first feeder platform is then raised and secured to the second feeder platform, and redundant supports of the first and second feeder platforms are removed. To complete the feeder and feeder cabinet removal process, upper feeders (i.e., connecting upper fuel channel assemblies 28 on the reactor face) are then removed from the joined first and second feeder platforms.
Examples of upper feeders to be cut are shown at 88 in FIG. 9.
[0031] FIGS. 4 and 5 illustrate an example of a feeder cabinet 68 to which the process of the present invention can be applied. The illustrated feeder cabinet 68 includes a front face 70, a soffit 72, and an upper feeder cabinet rear wall 74. Each of these components 70, 72, and 74 is removed during feeder cabinet removal. Side walls 76 and a lower back wall 78 of the cabinet = CA 02766470 2012-01-16 Attorney Docket No. 027813-9028 68 can remain in place. In some embodiments, scissor lifts 80 (see FIGs. 8 and 11) may be used to remove the front face 70 of the feeder cabinet 68.
[0032] A feeder platform, including the front feeder platform 81 (FIG. 9) and rear feeder platform 82 (see FIG. 10) will be used for the removal of the soffit 72 and upper cabinet rear wall 74. As illustrated in Fig. 10, the feeder platforms 81, 82 may be suspended from support members coupled to support framework above the soffit, or from the soffit itself. The support members may includes cables, ropes, chains or other suitable support devices and systems for platforms. A vertical position of the feeder platforms 81, 82 may be adjusted by known vertical control means including pulleys, strand jacks, chain hoists, etc.
[0033] In some embodiments, the feeder cabinet 68 is disassembled and removed by detaching panels 84 and frame members 86. FIG. 8 illustrates a feeder cabinet 68 in the process of being disassembled. The feeders 59 are visible behind portions of the front face 70 that have been removed. FIG. 9 illustrates an exposed calandria end shield 64, as well as feeders 59 associated with one side of the reactor 6, each of which extends and is connected in fluid communication with a respective fuel channel assembly 28.
[0034] Once the feeder cabinet 68 has been removed as just described, the process of removing the feeders 59 can commence. However, it should be noted that in some embodiments of the present invention, the process of feeder cabinet removal overlaps to some extent with the process of feeder removal.
[0035] With reference now to FIG. 11, the feeders 59 include upper feeders 88 and lower feeders 90, each of which extends to and is connected to a respective fuel channel assembly 28 at the upper portion and lower portion of the calandria, respectively. As best shown in FIG. 11, the feeders 59 are removed by cutting and disconnecting each feeder 59 at particular locations along the length of each feeder 59 in a particular sequence of steps, thereby not only resulting in a highly efficient feeder removal process, but also reducing the opportunities for removal error, operator injury due to falling reactor components and tooling, and contamination of the area in front of the reactor face with debris (some of which can be radioactive) from disconnected and/or severed feeders 59.

Attorney Docket No. 027813-9028 [0036] Once the feeder cabinet removal steps have been completed, and the front and rear feeder platforms 81, 82 have been elevated to their respective positions above the vault crane 83, (see FIG. 3), the Retubing platform 98 (RTP) can be installed in front of the reactor face (and below the front and rear feeder platforms 81 and 82) in preparation for removing the upper and lower feeders 88, 90. The RTP 98, in combination with the front feeder platform 81 and rear feeder platform 82, provide for a worksite that has at least three work platforms that can be moved in space substantially independently. This allows for parallel series of work to occur on the reactor face, hence reducing the worker radiation dose, production costs, and schedule.
[0037] While an exemplary RTP 98 is illustrated in FIGs. 4 and 11, it should be understood that a substantially similar RTP can be provided on either end of the reactor core. Therefore, it will be understood that the description of the RTP herein relates to the illustrated RTP 98, but that multiple RTPs 98 having the same features and capabilities can be provided to enable servicing both end faces of the reactor core simultaneously.
[0038] In some embodiments, the RTP 98 is a stand-alone powered elevating platform that provides access to the reactor face for retube work. Referring to FIG. 11, the RTP 98 includes a plurality of columns 104 (e.g., four vertical columns from the a reactor vault floor, in the illustrated embodiment), a platform 106 movably supported by the columns 104, and an elevator system 108 for moving the platform 106 vertically relative to the columns 104.
[0039] The illustrated RTP platform 106 includes a structural (e.g., steel) frame 110 and a decking surface 112 coupled to the frame 110. The platform 106 can be sized (spatially and structurally) to accommodate all of the required tooling for retubing removal and installation processes, including support and movement of heavy shielded flasks used to transport radioactive reactor components removed from the reactor during retubing operations. By way of example, the platform 106 can provide a working surface of about 500 square feet or more (e.g., the width can be about 29-31 feet, and the length can be about 17-24 feet), and can provide a working surface nearly filling the plan view area that the fueling machine and gantry of the reactor normally occupy. To maximize working space, the RTP platform 106 can provide small clearances with respect to surrounding structures, including the underside of the RTP platform 106 when the RTP platform 106 is at its lowest elevation. Also, in some embodiments the ' Attorney Docket No. 027813-9028 platform 106 can be movable via the elevator system 108 to have a vertical stroke that is at least equal to the height of the calandria 10 (about 22 feet, in some cases), so that all of the fuel channel assemblies 28 across the entire reactor end face are accessible from the RTP platform 106. In the illustrated embodiment, the vertical stroke is about 27 feet, or about 5 feet more than the height of the illustrated calandria 10. Also, the elevator system 108 can position the RTP
platform 106 at any desired height within the vertical stroke. Although the RTP 98 may be configured to lower the platform 106 into a pit or recess in the vault floor, this is dependent upon the vault design at a particular reactor site, and is not required.
[0040] The platform 106 provides a base upon which precision tooling can be supported at different elevations of the platform 106, as well as a personnel work platform onto which tooling required for reactor disassembly and reassembly can be mounted. The significant accuracy with which the RTP 98 moves to position tooling with respect to the fuel channel assemblies 28 on the reactor face is achieved by providing the RTP platform 106 with high relative rigidity and stability. The RTP 98 can also serve as the primary elevating device for movement of the heavy shielded flasks from a lower elevation (e.g., vault floor) to the target lattice site, and back down to the lower elevation. In this regard, the use of the RTP 98 provides a more efficient method of vertical movement than individually craning each of the large flasks down to a lower elevation.
[0041] As indicated in FIG. 3, in some embodiments prior to the steps of feeder removal, positioning hardware assemblies 60 and closure plugs 52 are removed from each of the fuel channel assemblies 28 (see FIG. 2) by personnel on the RTP platform 106, and the couplings connecting the feeder assemblies 54 to the fuel channel assemblies 28 are also disconnected by personnel on the RTP platform 106. When this process is completed, and in an effort to assist in the process of feeder removal, the front feeder platform 81 (FIGs. 9 and 10) is lowered to a position in which personnel have easy access to the lower feeders 90 from both the front feeder platform 81 and the RTP platform 106.
[0042] With reference now to FIG. 9, a lower horizontal portion 92 of each lower feeder 90 is removed first. For this purpose, a first cut is made from scissor lifts to each lower feeder 90 at its 45-degree bend 96 located beyond a respective cantilever support 94 supporting the lower feeder 90. A cantilever support 94 is a supporting structure used to restrain displacement of Attorney Docket No. 027813-9028 select feeders 59 in the CANDUTM reactor. The lower feeders 90 are cut and removed in this manner from outboard-most lower feeder 90 to inboard-most lower feeder 90, top to bottom.
Each cut feeder section can be capped from the RTP platform 106, whereas the other cut ends of the lower feeders 90 can be capped from scissor lifts 30 just after cutting to contain any loose contamination. Referring to FIG. 11, as the lower feeders 90 are cut, the lower feeders 90 can be moved onto the RTP 98 and placed at the rear of the RTP platform 106. For long feeder sections, an additional cut can be made from the RTP 98 as needed.
[0043] As shown in FIG. 6, an overhead crane 114, located above a catwalk 116 (see FIG.
11), can be used to remove bulk feeder sections from the RTP 98 and to place them on carts at one end of the RTP 98. The loaded carts can then be rolled around the vault and out of an air lock for further processing. The cantilever supports 94 (FIG. 9) that each supported at least one respective lower feeder 90 can also be removed along with the first cut and removed section of each lower feeder 90. Although the hardware used to secure the cantilevered supports 94 in place may not be reused, the cantilever supports 94 may be refurbished as desired.
[0044] To complete removal of the lower feeders 90 a second cut can be made to each lower feeder at an existing field weld location 117 (FIG. 11). The front feeder platform 81 (see FIG.
10) can be lowered to the elevation of the floor of the reactor vault in order for workers to reach the existing field weld location for each lower feeder 90. Feeder hanger supports 119 (FIG. 11) may be inspected ahead of time to ensure they can be used as lifting points to lower the feeders 59 onto the RTP 98 or to the vault floor. To facilitate movement of the cut feeders 59, the feeders 59 can he rigged with slings prior to cutting. For longer cut feeder sections, an additional cut may be done on the RTP 98 or on the vault floor as needed. The sections can then be loaded onto carts and rolled out a first air lock for further processing. Various lower feeder spacer hardware can be removed during removal of the second sections of the lower feeders 90, and may not be used in some embodiments to allow for quick removal and clean installation.
[0045] With reference again to FIG. 3, after the lower feeders 90 have been removed, removal of the upper feeders 88 can begin. To commence upper feeder removal, the front feeder platform 81 can be raised above the vault crane 83 and can be secured in placed (e.g., bolted) to the rear feeder platform 82 (FIG. 10), with a falling-object barrier (e.g., a net or other obstacle) = CA 02766470 2012-01-16 Attorney Docket No. 027813-9028 put in place therebetween so that other retubing operations can begin on the reactor face while the upper feeders 88 are still being removed. A decision to allow upper feeders 88 to be removed while other reactor retubing processes are taking place can be made following appropriate radiation protection assessments.
[0046] As shown in FIG. 6 and 7, in some embodiments a monorail 118 is installed above the catwalk 116 (FIGs. 6 and 11), between inlet and outlet headers 115 (FIGs.
6 and 10). The monorail 118 helps support the upper feeders 88 during upper feeder removal and installation, and may be used as a means to support the upper feeders 88 during their transport to a hoist well 120 defined in the catwalk 116 (FIG. 6). The hoist well 120 allows for lowering and raising the upper feeders 88 via the crane 114. Once feeders 59 are lowered, the feeders 59 can be loaded onto carts or waste containers and rolled around the sides of the vault, and out of an air lock.
[0047] Removal of upper feeders 88 is performed from a first end to a second end across the reactor face. Accordingly, sections of the catwalk 116 will be removed as the upper feeders 88 are removed. This catwalk 116 may be retained, refurbished and re-installed.
[0048] The upper feeders 88 may be slung from the monorail 118 and cut several inches from the headers 115, more specifically, the nozzles of each header 115. Each upper feeder may then be transferred to a location with a hoist well (e.g. hoist well 120).
[0049] In some embodiments, upper feeder spacers are removed at the same time as the upper feeders 88 are removed. Other tubing and components may be removed as well.
Resistance temperature detector (RTD) lines may cut at an accessible area where welding can take place for re-installation as needed.
[0050] Understanding that both sides of the reactor have similar components that are likely to be removed and/or refurbished at the same time, it will be appreciated that lower feeder cabinet removal may be done with two crews per face of the reactor, working in parallel.
Another crew may be on the vault floor transferring material from the removal crew to waste bins. Also, upper feeder cabinet removal may be done with, for example, a large crew of eight individuals per reactor face, which includes a crew of two individuals per face standing on the vault floor for material handling. Due to space constraints, upper feeder removal may be done Attorney Docket No. 027813-9028 with one crew per reactor face, but upper feeder removal can be performed in parallel to other activities on the RTP 98 as discussed above.
[0051] A number of commercial production tools may be employed in the feeder cabinet and feeder removal processes described herein. By way of example only, a reciprocating saw can be used for cutting feeders, and can also be used for feeder waste processing, whereas a portable band saw can be used to process feeders into pieces small enough to fit into waste containers. As another example, manual bolt cutters can be used to cut small diameter piping and components such as RTDs, orifice and tube cutting, cantilever beam support hardware cutting, and spacer removal. As yet another example, battery-powered bolt cutters can also be used for RTD and tube cutting, cantilever beam support hardware cutting, and spacer removal. A
portable grinder can be used for hanger rods and cantilever beam hardware.
[0052] The embodiments described above and illustrated in the figures are presented by way of example only and are not intended as a limitation upon the concepts and principles of the present invention. As such, it will be appreciated by one having ordinary skill in the art that various changes in the elements and their configuration and arrangement are possible without departing from the spirit and scope of the present invention as set forth in the appended claims.

Claims (13)

1. A method of removing feeders from a nuclear reactor plant, the method comprising:
suspending a feeder platform before a face of a nuclear reactor of the nuclear reactor plant at a first height;
removing at least a portion of a soffit of a first feeder cabinet using the feeder platform;
raising the feeder platform to a second height above the first height;
installing a retubing platform (RTP) before the face of the nuclear reactor and below the feeder platform after removal of the portion of the soffit, wherein the RTP is movable to different positions before the face of the nuclear reactor, independent of the movement of the feeder platform;
disconnecting a feeder coupling;
cutting a feeder; and removing the feeder.

2. The method of claim 1, wherein the act of suspending the feeder platform includes suspending the feeder platform beneath the soffit from overhead supports

3. The method of claim 2, wherein the feeder platform is a front feeder platform the method further comprising suspending a rear feeder platform beneath the soffit;
removing at least an additional portion of the soffit from the rear feeder platform; and raising the rear feeder platform prior to installation of the RTP.

4. The method of claim 1, wherein the act of removing the feeder includes removing a lower feeder using a combination of the feeder platform and the RTP.

5. The method of claim 3 further comprising securing the front and rear feeder platforms together, wherein the feeder that is cut and removed is an upper feeder that is removed from the secured front and rear feeder platforms.

6. The method of claim 1, further comprising removing cantilever supports.

7. A method of removing feeders from a nuclear reactor plant, the method comprising:
installing a first platform movable to different elevations across a face of the reactor plant;
adjustably suspending the first platform to the different elevations across the face of the reactor plant;
installing a second platform also movable to different elevations across the face of the reactor plant and independently of the first platform;
installing a third platform also movable to different elevations across the face of the reactor plant and independently of the first and second platforms; and supporting the third platform upon at least two columns fixed to a floor of the nuclear reactor plant, cutting and removing a feeder using the first platform along with either the second platform or the third platform.

8. The method of claim 7, further comprising removing a first feeder cabinet wall.

9. The method of claim 8, wherein the act of removing the first feeder cabinet wall is at least partially performed from a scissor lift.

10. The method of claim 7, further comprising removing a first feeder cabinet soffit using the first platform.

11. The method of claim 10, further comprising removing a second feeder cabinet soffit using the second platform.

12. The method of claim 7, wherein the act of removing the feeder includes removing an upper feeder and a lower feeder.

13. The method of claim 7, further comprising installing a monorail adjacent headers of the nuclear reactor.