CA2766583A1 - Methods and apparatus for handling materials for retubing of a nuclear reactor - Google Patents

Abstract

A method of calandria tube volume reduction during calandria tube replacement.
The method includes the steps of removing at least one of an end fitting, a pressure tube, a calandria tube, and a garter spring from a nuclear reactor at the reactor face; placing at least one of an end fitting, a pressure tube, a calandria tube, and a garter spring into a flask at the reactor face; transporting the flask away from the reactor; removing at least one of an end fitting, a pressure tube, a calandria tube, and a garter spring from the flask; and performing volume reduction on the at least one of an end fitting, a pressure tube, a calandria tube, and a garter spring.

Description

Attorney Docket No. 027813-9032-CAOO

METHODS AND APPARATUS FOR HANDLING MATERIALS FOR RETUBING OF A
NUCLEAR REACTOR

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to U. S. Provisional Patent Application No.
61/433,398, filed January 17, 2011, the contents of which are herein incorporated by reference.
BACKGROUND

[0002] The present invention relates to methods and apparatus for retubing of a nuclear reactor.

[0003] More specifically, the invention relates to methods and apparatus for handling materials for retubing 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 one embodiment, the invention provides a method of calandria tube volume reduction during calandria tube replacement. The method includes the steps of removing at least one of an end fitting, a pressure tube, a calandria tube, and a garter spring from a CANDU
reactor at the reactor face; placing the at least one of an end fitting, a pressure tube, a calandria tube, and a garter spring into a flask at the reactor face; transporting the flask away from the reactor; removing the at least one of an end fitting, a pressure tube, a calandria tube, and a garter spring from the flask; and performing volume reduction on the at least one of an end fitting, a pressure tube, a calandria tube, and a garter spring.

[0005] In another embodiment the invention provides method of calandria tube volume reduction during calandria tube replacement. The method includes the steps of removing at least one of an end fitting, a pressure tube, a calandria tube, and a garter spring from a CANDU
reactor at the reactor face; placing the at least one of an end fitting, a pressure tube, a calandria tube, and a garter spring into a flask at the reactor face; transporting the flask outside a vault Attorney Docket No. 027813-9032-CAOO

containing the reactor; removing the at least one of an end fitting, a pressure tube, a calandria tube, and a garter spring from the flask; and performing volume reduction on the at least one of an end fitting, a pressure tube, a calandria tube, and a garter spring.

[0006] In another embodiment the invention provides a material handling system for use during retubing of a CANDU reactor. The material handling system includes a track system including a plurality of track sections, wherein the track sections include at least one curved track section. The system also includes a trolley having a cargo bed, at least two wheel trucks operatively coupled to the cargo bed, and a guide mechanism for interacting with the track system, wherein at least one of the wheel trucks pivots relative to the cargo bed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Various aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.

[0008] Figure 1 shows the general flow of a full End Fitting (EF) flask from a platform tooling.

[0009] Figure 2 shows the general flow of an empty EF flask to the platform tooling.

[0010] Figure 3 shows an embodiment of a trolley.

[0011] Figure 4 shows an embodiment of a trolley with a PT-CT-GS flask.

[0012] Figure 5 shows an embodiment of a trolley with an EF flask.

[0013] Figure 6 shows an embodiment of a straight rail and sole plate section.

[0014] Figure 7 shows an embodiment of a rail and sole plate layout in the reactor building.

[0015] Figure 8 shows an embodiment of a trolley side shift assembly.

[0016] Figure 9 shows the complete track system and identifies the section that is shown in detail in Figures IOA and IOB.

Attorney Docket No. 027813-9032-CAOO

[0017] Figure 1 OA shows a trolley side shift assembly connecting a first trolley track.

[0018] Figure 1 OB shows the trolley side shift assembly connecting a second trolley track.

[0019] Figure 11 shows an embodiment of a truck gantry.

[0020] Figure 12 shows an embodiment of a buffer nest.

[0021] Figure 13 shows an embodiment of a buffer nest with two EF flasks.

[0022] Figure 14 shows an embodiment of a buffer nest with one PT-CT-GS flask.

[0023] Figure 15 shows an embodiment of a flatbed nest.

[0024] Figure 16 shows an embodiment of a two flatbed nests on flatbed trailer holding two EF flasks each.

[0025] Figure 17 shows an embodiment of a two flatbed nests on flatbed trailer with one PT-CT-GS flask each.

[0026] Figure 18 shows an embodiment of a flatbed trailer schematic.

[0027] Figure 19 shows an embodiment of a flatbed trailer with tooling mounted thereon.

[0028] Figure 20 shows an embodiment of a building extension (box shown in bottom center of drawing).

[0029] Figure 21 shows a material handling tooling layout for an EF flask.

[0030] Figure 22 shows an embodiment of a shuttle flask.

[0031] Figure 23 shows an embodiment of an end fitting shield plug removal tool with a shuttle flask attached thereto.

[0032] Figure 24 shows an embodiment of EF Pulled into EF flask.

[0033] Figure 25 shows an embodiment of EF Removal Tooling Retracted and EF in EF
flask.

Attorney Docket No. 027813-9032-CA00

[0034] Figure 26 shows an embodiment of Removal of a Full EF flask from the Platform Tooling.

[0035] Figure 27 shows an embodiment of Installation of an Empty EF flask to the Platform Tooling.

[0036] Figure 28 shows an embodiment of a layout of an EF removal tool set.

[0037] Figure 29 shows an embodiment of a Removal of a full CT-PT-GS flask from the platform Receive tooling.

[0038] Figure 30 shows an embodiment of an Installation of an empty CT-PT-GS
flask to the platform receive tooling.

[0039] Figure 31 shows an embodiment of a CT-PT-GS flask.

[0040]

[0041] Figure 32 is a perspective view of a reactor core of a CANDU-type reactor 6.

[0042] Figure 33 is a cut-away view of the fuel channel assembly.

DETAILED DESCRIPTION

[0043] 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.

[0044] The following is a description of one or more embodiments of methods and apparatus for handling materials for retubing of a nuclear reactor such as a CANDU
reactor.

[0045] Figure 32 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 Attorney Docket No. 027813-9032-CAOO

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 Figure 32, 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.

[0046] Figure 33 is a cut-away view of the fuel channel assembly 28. As illustrated in Figure 33, 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.

[0047] 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.

[0048] 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.

[0049] As also shown in Figure 33, an end fitting 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. 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 Attorney Docket No. 027813-9032-CAOO

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 Figure 33, the feeder assemblies 54 can be attached to the end fitting 50 using a coupling assembly 56 including a number of screws, washers, seals, and/or other types of connectors.

[00501 Coolant from the inlet feeder assembly 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 assembly 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 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 Figure 32, feeder tubes 59 are connected to the feeder assemblies 54 that carry coolant to or away from the reactor 6.

[00511 Returning to Figure 33, 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.

[00521 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.

[00531 Material handling refers to tooling whose primary function is to move and manipulate shielded flasks containing radioactive materials that are being removed from the reactor and Attorney Docket No. 027813-9032-CAOO

transported to the waste processing facility. The secondary function of the material handling tooling is to assist in the movement of face tooling and materials during retube operations.
[0054] Material handling tooling consists of a system of trolleys, rails, rail switching equipment, nests and cranes used to manipulate and transport flasks and other equipment to and from the opposing faces of the reactor. The tooling is designed to be used in conjunction with the reactor area (RA) cranes.

[0055] The material handling equipment is in "production" operation during three series: the End Fitting (EF) Removal series, the calandria Tube Insert (CTI) Removal series, and the Pressure Tube-calandria Tube-Garter Spring (PT-CT-GS) Removal series. The material handling method is the same whether the PT and CT are removed together or separately.

[0056] Material handling tooling is installed prior to the EF Removal series (during the PT
and Bellows Cut series) and removed after completion of the PT-CT-GS Removal series. The exception is the truck gantry which will be installed at the beginning of the retube outage and continue to function for the duration of the outage.

[0057] There are eight major components to the material handling system: a trolley, trolley rails and sole plates, a trolley side shift assembly, a truck gantry, a buffer nest, a flatbed nest, a flatbed trailer, and a weather enclosure.

[0058] Figure l shows steps 1-4 (below) of the general procedure at the reactor for all three removal series. Figure 2 shows the reverse process (labelled in reverse as steps 1-4) for returning an empty flask from the truck to the face of the reactor. In general, the procedure includes: (1) An empty flask is mounted on the removal tooling at the face of the reactor. The EF flasks will need to reach both vaults, whereas the longer PT/CT flask only needs to reach the nearer vault. (2) The empty flask is filled with radioactive materials from the removal series.
This now becomes a full flask. (3) The full flask is unloaded from the removal tooling to the trolley using the RA crane. The fuel channel platform (FCP) (or retube platform, RTP) may be positioned at floor level to facilitate and simplify flask movements. (4) The full flask is taken out of the reactor vault to the truck loading area via trolley. (5) Using the truck gantry, the full flask is removed from the trolley and loaded onto the first buffer nest. (6) An empty flask is Attorney Docket No. 027813-9032-CAOO

removed from the second buffer nest and placed on the trolley using the truck gantry. (7) The trolley moves from the truck loading area to the reactor face with the empty flask. (8) The cycle starts again from Step 1.

[0059] Radioactive material is contained within the shielded flasks at all times when removed from the reactor face.

[0060] While the removal operations are occurring on the reactor face, and while the trolley is moving back and forth from the reactor and the truck loading area, the operators in the truck loading area will be working in parallel. Empty flasks arriving on the truck will be moved to the first buffer nest in advance. When full flasks arrive on the trolley, they will be unloaded to the second buffer nests instead of being loaded directly to the truck. The buffer nests are much closer to the trolley stop position and this minimizes the time to exchange full flasks for empty ones. This in turn minimizes the waiting time at the face for empty flasks to arrive.

[0061] In general, the procedure at the truck loading area includes: (1) A
truck from the processing facility containing empty flasks will enter the truck loading area in the reactor and park. (2) The doors on the weather enclosure will be closed so that the entire truck is protected from the elements. The cover for the flatbed will be rolled back and the empty flasks on the flatbed nests will be unsecured for hoisting. (3) Using the truck gantry, an empty flask will be hoisted and moved from the flatbed nest to the first buffer nest. For CTI and EF flasks, two flasks can be placed in a single buffer nest. (4) A trolley with a full flask from the reactor arrives in the truck loading area. (5) The full flask on the trolley will be loaded onto the second buffer nest. (6) The empty flask will be loaded from the first buffer nest onto the trolley and sent back to the reactor. (7) The full flask on the second buffer nest will be loaded and secured onto the flatbed nest. (8) Repeat Steps 3 to 7 until there are no more empty flasks.
(9) When the flatbed nest is full of full flasks, the cover on the flatbed will be closed and the truck will leave for the processing plant. (10) The truck arrives at the processing plant and the full flasks will be removed and empty flasks will be loaded. (11) The truck returns to the reactor with empty flasks. (12) Repeat from Step 1.

[0062] In some embodiments, there are at least two trucks running in parallel at all times in order to minimize flask wait times.

Attorney Docket No. 027813-9032-CA00 [0063] At all times, exchanging flasks on incoming trolleys will be the highest priority. To this effect, hoisting operations to load or unload the truck may not be as efficient in order to keep operations at the reactor moving as quickly as possible. Additionally, the buffer nests in the truck loading area allow hoisting operations to be flexible. Hoisting can continue while trolleys are moving through the vault or while operations happen on face.

[0064] Figures 3, 4, and 5 illustrate trolleys that are used to convey flasks, tooling and other materials from one end of both faces of the reactor to the truck loading area.
Flasks and other loads are lowered onto the bed of the trolleys. Each trolley has locating and positioning features to prevent loads from moving once placed on the trolley (e.g. nests for stabilizing loads as shown in Figures 3, 4, 5, and 12-14). The trolleys also include a guide mechanism for interacting with the track system, where the guide mechanism may include flanged wheels that rest on parallel rails. Alternatively, the guide mechanism may include a carriage attached to the trolley, where the carriage is in contact with a rail to guide the trolley.

[0065] In one embodiment, trolleys move on flanged wheels captured on tracks similar to railroad tracks. In various embodiments, the trolleys have two pivoting axles to allow tight turns to be made on curved tracks. In other embodiments, the wheels of the trolley are not be flanged and instead the trolleys have wheels (e.g. castered wheels) that run on the floor of the building.
The non-flanged wheels may roll directly on the floor of the building or on plates or other surfaces provided (e.g. to provide a smooth and level surface).

[0066] In various embodiments, the trolleys are powered by electric motors (e.g. mounted adjacent to wheel trucks under the trolley as shown in Figure 3), which may be manually controlled by an operator holding a pendant with a deadman trigger. In general, trolleys are equipped with brakes which automatically engage when not in motion to act as a parking brake, as well as an emergency brake when releasing the deadman trigger on the pendant. The bed of each trolley is quickly configurable with nests for carrying flasks, tools or other miscellaneous loads. In various embodiments, a standard trolley design will be used to carry all materials.
Each trolley has a cargo bed and at least two wheel trucks (e.g. see Figure 3), where at least one of the wheel trucks pivots relative to the cargo bed in order to permit the trolley to move on curved track portions.

Attorney Docket No. 027813-9032-CAOO

[0067] Under normal operation, one trolley is allocated for transferring all flasks from one face of the reactor and one trolley will be allocated for transferring all the flasks from the other face of the reactor. Details of the trolley operations and movements are found in the individual removal sections.

[0068] In various embodiments, trolleys are capable of towing/pushing other trolleys in case of motor failure. The trolleys also have the capability of being winched along the tracks in case of manual contingency operation.

[0069] In various embodiments, a track system (e.g. see Figure 1) including a plurality of track sections is installed in the reactor building. As discussed below, the plurality of track sections may include curved sections to allow the track system to be installed without having to remove existing reactor structures.

[0070] In some embodiments, trolleys move on rails similar to railroad tracks.
In those embodiments in which a rail or rails are employed (e.g. a pair of rails for use with flanged wheels or a single rail or multiple rails used to guide castered wheels as described above), the rail or rails may be mounted to a large sole plate which includes a track section sub-assembly. In addition to straight sections (shown in Figure 6), curved sections of track have been incorporated as well in order to avoid removing existing reactor structures. In general, where two (or more) rails are used to accommodate flanged wheels or to guide a carriage attached to the trolley, the rails are installed parallel to one another at a fixed distance apart.

[0071] Each sole plate will be equipped with quick jacking mechanisms for levelling as well as quick floor lagging provisions. This combined with the rails preassembled onto the sole plates will allow for maximum efficiency and ease of installation. Each of these track sections will be fully connected and tested prior to installation in the reactor, resulting in a minimum of on-site set up and adjustment. The vault floor will require inserts placed into the floor in advance of installation of the sole plates.

[0072] Sole plates in the airlock will not be lagged inside the airlock area but clamped just outside of the airlock envelope. The clamping allows for quick removal of the sole plates in the airlock in the event the airlock needs to be closed.

Attorney Docket No. 027813-9032-CA00 [0073] There is one main line (Item 1 in Figure 7) which stretches from one face of the reactor through the airlock (Item 4 in Figure 7) and out into the truck loading area (Item 5 in Figure 7). This main line contains docking stations at the trolley side shift assembly (Item 3 in Figure 7) and at the end of the rail in the truck loading area.

[0074] A secondary line (Item 2 in Figure 7) stretches through a side of the vault through the walkway. The trolley, EF flasks, and CTI flasks (not shown) are small enough in diameter to fit within the side doorways with clearance.

[0075] The trolley side shift assembly (Figure 8) is a track switching mechanism used to connect trolleys from either face of the reactor to the main line.
Additionally, due to the tight space constraints with the long PT-CT-GS flask, the direct, linear motion of the side shift is required to bring the flask within the envelope of the RA crane. In general the side shift assembly is mounted near the reactor to permit access to both faces of the reactor and to permit a trolley on one track section to be loaded and unloaded while another trolley moves past to the other side of the reactor (e.g. Figure 1).

[0076] This mechanism consists of a large slide plate with two sets of trolley rails mounted on it. The first set of rails is straight and the second set of rails is curved to provide a larger turning radius for the trolleys operating from one of the reactor faces. The slide plate is mounted on precision linear bearings and rails and is driven by a ball screw powered by a motor. The slide plate will move and align either the first trolley track or the second trolley track with the main line out of the airlock (see Figure 8).

[0077] When the second face trolley is aligned to the main line, the first face trolley is within the corresponding RA crane reach envelope. This allows the first face trolley to be loaded or unloaded from the reactor face while the second face trolley passes through.
When the first face trolley is aligned to the main line the second face trolley must wait until the side shift is performed.

[0078] The trolley side shift assembly is controlled by an operator using a simple pendant with a deadman trigger. The side shift movement will only continue while the operator presses the deadman trigger. The ball screw drive motor is equipped with a brake which automatically Attorney Docket No. 027813-9032-CAOO

engages when not in motion to act as a parking brake as well as an emergency brake when releasing the deadman trigger on the pendant. The trolley side shift assembly is designed to be brought into the vault as a single piece and installed as a complete turnkey sub-assembly.

[0079] The truck gantry (Figure 11) is a new installation to be erected in the area just outside of the shielding door of the airlock. This is the main gantry used in loading and unloading all trucks coming in the docking bay of the reactor building. Due to the close proximity to the vault airlock, the docking bay will handle the majority of tools and materials used for the duration of the retube operations.

[0080] The gantry is included in the Material Handling section of this proposal but will be installed at the beginning of the retube outage and used throughout the entire retube operation as the main truck load/unload crane.

[0081] The main function of the gantry during the removal series is to load and unload flasks from the trolleys, buffer nests and the flatbed nest. In addition, the gantry will be used to place and remove trolleys onto the tracks as well as materials and tooling used on face during the removal series.

[0082] This gantry is a custom frame gantry which will have travel in two axis as well as the hoist. The gantry will be made modular and designed for quick assembly without the use of heavy machinery. The gantry is fully certified as an overhead lifting device.

[0083] Lag studs will have to be pre-installed into the floor in the truck loading area prior to the gantry being brought on site.

[0084] The buffer nest (Figure 12) is a static cradle designed to hold a single CT-PT-GS
flask (Figure 14) or two EF flasks (Figure 13). The buffer nest provides a place to temporarily place a flask so a trolley or the flatbed nest can be cleared.

[0085] The buffer nests are heavy duty weldments which contain rough positioning features used to place the different flasks in repeatable locations. The positioning features have much greater clearances than those used on the trolleys or tools to allow for quick placement and pick up of flasks. The buffer nests will require lagging to the ground to prevent accidental movement.

Attorney Docket No. 027813-9032-CAOO

In some embodiments, there are two buffer nests positioned close to the trolley docking position in the truck loading area.

[0086] Lag studs will need to be pre-installed into the floor in the truck loading area prior to the buffer nests being brought on site.

[0087] The flatbed nest (Figure 15) provides a frame in which to secure flasks for transport via truck. The flatbed nest is bolted to the bed of the flatbed trailer and will remain in place for the duration of the removal series. The flatbed nest is designed to hold one CT-PT-GS flask (Figure 16) or two EF flasks (Figure 17) each. Two flatbed nests can be mounted in a single flatbed trailer.

[0088] Similar to the buffer nest, the flatbed nest is a heavy duty weldment which contains positioning features used to place the different flasks in repeatable locations. The positioning features are similar to those used on the trolleys or removal tools to prevent movement of flasks during truck transport. The flatbed nest also contains a quick chain winch tie-down system which will be integrated into the flask design. All tie-downs will be manually actuated. These will be custom tailored to the flasks so that securing and releasing the flasks from the nests will take a minimum of time and effort.

[0089] The nests need to be installed into the flatbed trailers prior to the beginning of the removal series.

[0090] The flatbed trailer (Figure 18) is used to transport flasks between the reactor building (RB) and the processing plant. The flatbed trailer is a drop deck roll-tight trailer which is custom-modified to carry extremely heavy loads. The trailer has a roll-tight cover which is a retractable fabric and metal frame bellows cover. The cover can quickly be rolled over the bed of the trailer providing a weatherproof enclosure around the load during transport. It can then be unrolled to provide full top and side access to the load. An embodiment of the flatbed trailer is shown in Figure 19.

[0091] In other embodiments, provisions are made for mounting the flatbed nest weldments, such that the flatbed trailer will hold a pair of flatbed nests.

Attorney Docket No. 027813-9032-CAOO

[0092] In some embodiments, trucks backing into the RB outside of the truck loading door cannot now drive fully inside the existing reactor due to unloading clearance requirements. This means that the loading door would remain open to the elements for extended periods. To prevent this scenario, a weather enclosure, or building extension (Figure 20), to the truck docking area will be constructed so the entire truck can be housed inside an enclosure and the RB can be isolated from the elements. This construction will include any reinforcement of the ground outside and inside the building loading dock, as well as guides and bumpers to facilitate the quick entry and exit of the trucks.

[0093] In some embodiments, an electric winch is used to move trolleys or to actuate the trolley side shift assembly in case of motor or ball screw failure. Regular mounting points along the track or trolley side shift assembly will be provided to connect the winch.

[0094] In some embodiments, a ratcheting come-along is used to move trolleys or to actuate the trolley side shift assembly in case of complete power failure. Mounting points along the track or trolley side shift assembly will be provided to connect the come-along.

[0095] Figure 21 shows the rail layout from a plan view of the RB. In the illustrated embodiment, the rail layout includes a main line I (through airlock), a secondary line 2 (through a vault corridor), a trolley side shift assembly 3, an airlock 4, a truck loading area 5, a truck gantry 6, a buffer nest 7, a flatbed nest 8, a flatbed trailer 9, and a weather enclosure 10.

[0096] The material handling system and flasks can be used in the end fitting removal series, as described below. In this series all EFs are removed from the reactor. The EF removal tooling on the platforms are identical. The EFs are removed simultaneously in a staggered fashion from both reactor faces to accommodate EF flask trolley vault traffic.

[0097] A single channel cycle involves removing an EF from a lattice site and placing it into a shielded flask, inserting a lattice sleeve assembly (LSA), removing the full flask from the vault, and installing an empty flask back onto the removal tooling. The cycle can begin by starting at the bottom row and working up the reactor face. In parallel, the full flask is being delivered to a volume reduction facility. In various embodiments, the volume reduction facility is located away from the reactor face, which may still be within the reactor vault or which may be outside Attorney Docket No. 027813-9032-CAOO

of the building containing the reactor. There the flask is emptied and returned in queue for reinstallation on the removal tooling.

100981 In one embodiment, the PT, CT, and GS are placed in the flask, which is then rotated on the platform. The platform is subsequently lowered to floor elevation. The volume reduction equipment is stationed on the floor beside the platform. The contents of the flask are pushed into the volume reduction machine and volume-reduced components fall into a flask that sits beneath the volume reduction machine. In general, the flask on the platform for the PT/CT/GS remains on the platform for the duration of the removal sequence, whereas the flask beneath the volume reduction machine is replaced when full.

[0099] The EF Removal Series can be divided into automated and manual operations. The automated operations may be controlled remotely from the retube control center (RCC) or locally from pendants and are those associated with the face operation with the tools on the heavy work table (HWT). This is for ALARA (as low as reasonably achievable) purposes, so that people may be kept away from the highly radioactive operations as much as possible. The manual operations are those associated with the hoisting and transportation of flasks and lattice sleeves.

[001001 The layout of the tools on the RTP is shown in Figure 28. These tools include an HWT 1, a pallet 2, a lattice tube shield plug insert removal tool (LS-SPIRT) 3, an EF flask 4, an EF retrieval head 5, and EF shield 6, an LSA 7, and a vision system 8. In various embodiments, these tools may be moved by the vault trolley system and hoisted by the RA
crane for vault transitions.

[001011 The process for removing an EF from a lattice site and placing it into an EF flask is as follows. Not all of the listed steps are required; for example, steps (8) and (9) may be omitted.
In various embodiments, all of the operations are carried out using automated tooling. (1) Prerequisites include: (a) The EF flask is mounted to the pallet, and a LSA is mounted to the EF
flask; and (b) The RTP is at the designated row. (2) The HWT moves to bring the vision system in front of the designated EF. (3) The vision system calculates the offsets for fine alignment and then the HWT moves to align the EF removal tooling to the EF. (4) The pallet z-drive advances the EF shield over the EF, and the pallet's Serapid drive advances the EF
Retrieval Head into the Attorney Docket No. 027813-9032-CAOO

EF. (5) The EF retrieval head grips the EF. (6) The pallet's Serapid drive pulls the EF into the flask (Figure 24). (7) The pallet z-drive retracts the EF Shield from the EF, the EF Retrieval Head un-grips the EF, and the pallet's z-drive retracts the head out of the EF
flask back into the guide tube. (Figure 25). (8) The HWT indexes in the x-direction to align the vision system to the open channel. (9) The vision system shoots the outboard journal ring and CTI
to establish the x-, y-, pitch-, and yaw- coordinates for the lattice site. These values are stored for use by all other automated series that follow. The vision system does not have to be shot again unless there are problems with the tool accessing the site because of alignment issues. (10) The HWT indexes in the x-direction to align the axis of the LS SPIRT with the lattice site. (11) The LS SPIRT
advances to install the LSA into the lattice site. (12) The LS SPIRT retracts fully.

[001021 Replacement of a full EF flask with an empty EF flask at the platform tooling is a manual process that requires the use of the vault RA cranes, vault trolley system, and truck loading facility. The removal of the full EF flask from one side is shown in Figure 26, and the installation of the empty EF flask to the side is shown in Figure 27.

[00103] Before beginning the procedure, one empty trolley is waiting to be loaded on the side shift mechanism and the RTP is aligned at the designated row. In various embodiments, the procedure for a flask replacement can include some or all of the following steps: (1) The platform is lowered to the floor, and the HWT moves to a predetermined location. (2) Personnel enter the platform. (3) The shielded doors on the full EF flask are closed and the LSA supports are folded in. (4) The crane is positioned over the full EF flask. (5) The crane hook and guide cables are installed on the full EF flask. (6) The RA crane and guide cables are used to hoist the full EF flask to another section of the RTP. The full EF flask is rotated while hung on the crane to achieve the correct orientation to be placed on the trolley (Step I in Figure 26). (7) The full EF flask is lowered onto the trolley and the RA crane and cable guides are disconnected. (8) The trolley with the full EF flask is side shifted using the trolley side shift assembly. The trolley now lines up with the tracks exiting out the airlock (Step 2 in Figure 26). (9) The trolley is driven through the airlock to the truck loading area (Step 3 in Figure 26). (10) The truck gantry and cable guides are connected to the full EF flask. The full EF flask is hoisted and moved to buffer nest #2. The gantry and cable guides are disconnected (Step 4 in Figure 26).
(11) The truck gantry and cable guides are connected to the empty EF flask in buffer nest #1.
The empty EF

Attorney Docket No. 027813-9032-CA00 flask is hoisted and moved to the trolley. The gantry and cable guides are disconnected (Step I in Figure 27). (12) The trolley with the empty EF flask is driven through the airlock to the trolley side shift assembly at the reactor face (Step 2 in Figure 27). (13) The trolley with the empty EF
flask is side shifted so it is within the RA crane envelope (Step 3 in Figure 27). (14) The LSA
supports are extended and the LSA is manually loaded onto the EF flask using the LSA loading mechanism (in other embodiments the LSA is mounted to the flask in an earlier step). (15) The RA crane and cable guides are connected to the empty EF flask. (16) The EF
shield should be in its forward position to provide clearance for the EF flask. (17) An empty EF
flask is loaded on the pallet (step 4 in figure 27). (18) The operator manually retracts the EF
Shield and couples it to the EF flask. (19) All operators leave the RTP, and the platform is raised from floor level to the designated row.

1001041 The procedure for replacing an EF flask on the other side of the reactor is very similar to the side discussed above. trolleys coming and going to the other side will not need to be side shifted and pass directly through on the curved track section of the trolley side shift mechanism.
EF flasks from the other face will travel on a secondary line which is laid in another area of the vault. This secondary line is connected to the main line out of the airlock at the trolley side shift assembly.

[001051 Additional work is performed in the truck loading area to prepare and clear flasks from the buffer nests and the truck. These processes are performed in parallel with work on the face and during trolley movement on the track. Operations in the truck loading area are described elsewhere in this document.

[001061 Replacement of a full CT-PT-GS flask with an empty CT-PT-GS flask at one platform receive tooling is a manual process that requires the use of the vault crane, vault trolley System, and truck loading facility. The removal of the full CT-PT-GS flask is shown in Figure 29, and the installation of the empty CT-PT-GS flask is shown in Figure 30.
The process is as follows: (1) One empty trolley is waiting to be loaded on the side shift mechanism, and the RTP
start at the designated row, and no workers are on the RTP. (2) The platform with the Guide Tooling remains at its current location. The other platform is lowered to the floor, and the HWT
moves to a predetermined location. (3) The shielded doors on the full CT-PT-GS
flask are Attorney Docket No. 027813-9032-CAOO

closed. (4) The crane is positioned over the full CT-PT-GS flask and the crane hook and guide cables are installed on the full CT-PT-GS flask. (5) The vault crane and guide cables are used to hoist the full CT-PT-GS flask to another section of the RTP. The full CT-PT-GS
flask is rotated while on the crane to achieve the correct orientation to be placed on the trolley. (6) The full CT-PT-GS flask is lowered onto the trolley and the vault crane and cable guides are disconnected.
(7) The trolley side shift assembly is used to line up the trolley with the tracks exiting out the airlock. (8) The trolley is driven through the airlock to truck loading area.
(9) Connect the truck gantry and cable guides, lift the full CT-PT-GS flask off trolley, rotate and hoist to buffer nest #1. Disconnect the gantry and cable guides. (10) Connect the truck gantry and cable guides, lift the empty CT-PT-GS flask from buffer nest #2, rotate and hoist to the trolley.
(11) Disconnect the gantry crane and cable guides and drive the trolley with the empty CT-PT-GS flask to the reactor face. (12) Using the trolley side shift assembly, move the trolley with the empty CT-PT-GS flask to within the vault crane envelope. (13) Connect the vault crane and cable guides, hoist the empty CT-PT-GS flask from trolley to Tool. The CT-PT-GS flask is rotated while on the crane to achieve the correct orientation to be placed on the tool. (14) The platform is raised from floor level to the designated row, and the other platform is moved to the designated row if required.

[00107] A CT-PT-GS flask is shown in Figure 31. In various embodiments, the functional requirements of the CT-PT-GS flask are as follows: (1) Houses a single CT and partial length PT, and four GSs. (2) Ends can be opened to permit loading and unloading operations. (3) ALARA shielding, permitting manual hoist and transport operations when the ends are closed.
(4) The inner surfaces shall permit easy cleanup. (5) The outer surfaces shall decontaminate easily to permit transport. (6) As much as possible the design shall not allow radionuclides to fall out to the environment or contaminate the outside of the flask when the ends are open during loading and unloading operations. (7) Contamination control to prevent the escape of radionuclides from the inside to the environment when the end have been closed, particularly during hoisting and transport operations. (8) Guidance for the Serapid chain ram and CT
Retrieval Head when they are advanced and retracted by the pallet. (9) Lift points for hoisting and attachment points for guide cables. (10) Include a brake mechanism for the second pull with the CT Retrieval Head. (11) Mount securely to the top of the pallet. (12) Allow transport via Attorney Docket No. 027813-9032-CAOO

trolley system in the vault and truck to on-site volume reduction facility.
(13) Interface with tooling at the volume reduction facility for unloading. (14) Designed for storage in type-A
container outside. (15) Function as an accessory to the pallet.

[00108] In various embodiments in which personnel are working with the CT-PT-GS flask, the shielding is designed for minimal radiation exposure to the personnel when the flask is filled.
Its features are designed with ALARA principles in mind, such that personnel minimize the amount of time they are in close proximity to the CT-PT-GS flask during hoisting and transport activities. Manual operations on the CT-PT-GS flask include opening and closing the shielded doors, locking and unlocking the shielded doors, rigging for hoisting, hoisting to and from the trolley system, pallet, and truck, and transport on the trolley system.

[00109] The Brackets incorporate contact points that guide the CT-PT-GS flask into precise alignment on the pallet during installation. The pallet and CT-PT-GS flask are designed with adequate clearances to allow for easy installation and removal of the CT-PT-GS
flask.

[00110] The CT-PT-GS flask includes features that function with the automated system.
These include an electromechanical brake mechanism on the body of the flask that engages with the CT Retrieval Head during the second pull, and sensors on the doors to indicate if they are open or closed. These devices use a quick disconnect for installation and removal of the CT-PT-GS flask.

[00111] In one embodiment, the body is made from carbon steel and the ends are made from lead. In other embodiments, the flask comprises a lead-filled steel shell. It is designed to be maintenance free during a retube outage, and requires maintenance in between retube outages.
[00112] Remove End Fittings / SP & Flasking [00113] After the pressure tubes are cut the end fittings are removed. The inboard end of the end fitting contains a portion of the pressure tube from the pressure tube cutting operation, also the fuel channel shield plug and liner tube are located in the end fitting and positioned at their design location. Because these components are highly radioactive a shuttle flask is used to provide the required shielding to reduce exposure to the worker. The shuttle flask is lowered onto Attorney Docket No. 027813-9032-CAOO

a trolley and rail system using a crane. The shuttle flask is then transferred to the End Fitting Transfer Station (EFTS) located in the vault where the EF is transferred to a Large Waste Transfer Flask (LWTF).

[00114] In various embodiments, the shuttle flask is lifted off the EFSP
removal tool with the Fuel Machine Bridge crane, then the shuttle flask is moved over the FCP hatch with the Fuel Machine carriage. This can be a bottle-neck due to the special care required to lift and move a 10 Ton weight across the platform to the hatch with very slow speed. The process is optimized by moving the shuttle flask over the hatch using the heavy work table. Once the flask is lifted with the crane, the heavy work table can be moved out of the way and the flask lowered to the vault floor. This simple change can reduce complication and save time as the heavy work table can transport the shuttle flask with a higher speed and less risk. The operation involving a 10 Ton object moving across the platform in mid air can thus be eliminated.

[00115] In those embodiments in which the End Fitting / SP Removal & Flasking series is performed at a high production rate, the optimization of the processes and tools as outlined contribute to minimizing the amount of time required to complete the work, resulting in lower costs and lower radiation exposure to workers.

1001161 The primary function of the EFTS is to safely transfer the EF from the shuttle flask into the Large Waste Transfer Flask (LWTF). At the reactor face, the EF is removed from the lattice site and pulled into the shuttle flask with the EFSP removal tool. The shuttle flask is then lowered onto the shuttle flask trolley located on the Fuelling Machine (FM) vault floor, using the FM bridge crane. The shuttle flask trolley is used to transfer the shuttle flask to the FM
maintenance lock. Once in the maintenance lock, the shuttle flask is lifted from the trolley and lowered onto the EFTS using the FM Maintenance Lock crane. One of the main components of the EFTS is the End Fitting Ram, which pushes the EF through Flask-to-Flask Interface (FFI) into the LWTF. The FFI is an interface that connects the shuttle flask and the LWTF that shields the operator from unnecessary radiation doses.

[00117] Remove Pressure Tubes & Flasking Attorney Docket No. 027813-9032-CAOO

[00118] The main objective of the Pressure Tube Removal & Flasking series is to pull the pressure tube from the fuel channel and into a volume reduction machine that will cut the pressure tube into small pieces and place those pieces into an attached small waste transfer flask.
Pressure tube removal series begins at the bottom row and works up to the next above row, from the lattice site near the middle of the calandria to the periphery channels.
Each VRS removes approximately half of the pressure tubes.

[00119] In the embodiment disclosed herein, the VRS is performed outside of the reactor vault such that the crushing machines can be larger and the crushing process can be performed in parallel, increasing the production rate. In those embodiments in which the Remove Pressure Tube series is performed at a high production rate, the optimization of the processes and tools as outlined contribute to minimizing the amount of time required to complete the work, resulting in lower costs and lower radiation exposure to workers.

[00120] Thus, the invention provides, among other things, methods and apparatus for handling materials for retubing of a nuclear reactor.

Claims (35)

What is claimed is:

1. A method of calandria tube volume reduction during calandria tube replacement, the method comprising:

removing at least one of an end fitting, a pressure tube, a calandria tube, and a garter spring from a CANDU reactor at the reactor face;

placing the at least one of an end fitting, a pressure tube, a calandria tube, and a garter spring into a flask at the reactor face;

transporting the flask away from the reactor;

removing the at least one of an end fitting, a pressure tube, a calandria tube, and a garter spring from the flask; and performing volume reduction on the at least one of an end fitting, a pressure tube, a calandria tube, and a garter spring.

2. The method of claim 1, wherein performing volume reduction further comprises performing volume reduction inside a vault containing the reactor.

3. The method of claim 1, wherein transporting the flask away from the reactor further comprises transporting the flask outside of a building containing the reactor.

4. The method of claim 1, further comprising returning the flask to the reactor.

5. The method of claim 1, wherein an end fitting is removed in substantially one piece.

6. The method of claim 1, wherein a pressure tube, a calandria tube, and a garter spring are removed as substantially one piece.

7. The method of claim 1, wherein removing at least one of an end fitting, a pressure tube, a calandria tube, and a garter spring from a CANDU reactor at the reactor face comprises mounting an empty flask onto the reactor face.

8. The method of claim 1, wherein transporting the flask away from the reactor comprises lifting the flask with a crane onto a trolley.

9. The method of claim 1, wherein transporting the flask away from the reactor comprises placing the flask onto a trolley system within the building containing the reactor.

10. The method of claim 8, wherein transporting the flask away from the reactor further comprises loading the flask onto a truck using a gantry.

11. A method of calandria tube volume reduction during calandria tube replacement, the method comprising:

removing at least one of an end fitting, a pressure tube, a calandria tube, and a garter spring from a CANDU reactor at the reactor face;

placing the at least one of an end fitting, a pressure tube, a calandria tube, and a garter spring into a flask at the reactor face;

transporting the flask outside a vault containing the reactor;

removing the at least one of an end fitting, a pressure tube, a calandria tube, and a garter spring from the flask; and performing volume reduction on the at least one of an end fitting, a pressure tube, a calandria tube, and a garter spring.

12. The method of claim 11, wherein transporting the flask outside a vault containing the reactor further comprises transporting the flask outside of a building containing the reactor.

13. The method of claim 11, further comprising returning the flask to the reactor.

14. The method of claim 11, wherein an end fitting is removed in substantially one piece.

15. The method of claim 11, wherein a pressure tube, a calandria tube, and a garter spring are removed as substantially one piece.

16. The method of claim 11, wherein removing at least one of an end fitting, a pressure tube, a calandria tube, and a garter spring from a CANDU reactor at the reactor face comprises mounting an empty flask onto the reactor face.

17. The method of claim 11, wherein transporting the flask away from the reactor comprises lifting the flask with a crane onto a trolley.

18. The method of claim 11, wherein transporting the flask away from the reactor comprises placing the flask onto a trolley system within a building containing the reactor.

19. The method of claim 18, wherein transporting the flask away from the reactor further comprises loading the flask onto a truck using a gantry.

20. A material handling system for use during retubing of a CANDU reactor, comprising:

a track system comprising a plurality of track sections, wherein the track sections include at least one curved track section; and a trolley comprising a cargo bed, at least two wheel trucks operatively coupled to the cargo bed, and a guide mechanism for interacting with the track system, wherein at least one of the wheel trucks pivots relative to the cargo bed.

21. The material handling system of claim 20, wherein each of the plurality of track sections comprises at least two adjacent rails, wherein the guide mechanism of the trolley comprises flanged wheels attached to the at least two wheel trucks, and wherein the flanged wheels are spaced to align with the rails of the track sections.

22. The material handling system of claim 20, wherein each of the plurality of track sections comprises a rail, and wherein the guide mechanism of the trolley comprises a carriage in contact with the rail.

23. The material handling system of claim 20, further comprising a side-shift assembly to link two portions of the track system.

24. The material handling system of claim 23, wherein the side-shift assembly comprises two track sections on a moveable sole plate, at least one of the two track sections being a curved track section.

25. The material handling system of claim 24, wherein the side-shift assembly comprises a curved track section and a straight track section.

26. The material handling system of claim 23, wherein the side-shift assembly is near the reactor.

27. The material handling system of claim 20, wherein the wheel trucks each comprise a plurality of wheels and wherein the trolley further comprises a motor operatively coupled to the at least one of the wheels to propel the trolley.

28. The material handling system of claim 20, wherein the cargo bed of the trolley further comprises a removable cargo nest.

29. The material handling system of claim 20, wherein at least one track section is attached to a sole plate.

30. The material handling system of claim 29, wherein the sole plate comprises a jacking mechanism for leveling the sole plate.

31. The material handling system of claim 29, wherein the sole plate is coupled to a floor.

32. The material handling system of claim 20, further comprising a flask for holding an element of the reactor in substantially one piece.

33. The material handling system of claim 32, wherein the element of the reactor is an end fitting.

34. The material handling system of claim 32, wherein the element of the reactor is a pressure tube-calandria tube-garter spring assembly.

35. The material handling system of claim 32, wherein the flask comprises a metal tube having at least one removable end.