CA2727492C - Method for removal of pressure tubes and calandria tubes from a nuclear reactor - Google Patents
Method for removal of pressure tubes and calandria tubes from a nuclear reactor Download PDFInfo
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- CA2727492C CA2727492C CA2727492A CA2727492A CA2727492C CA 2727492 C CA2727492 C CA 2727492C CA 2727492 A CA2727492 A CA 2727492A CA 2727492 A CA2727492 A CA 2727492A CA 2727492 C CA2727492 C CA 2727492C
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- calandria
- tube
- main
- bell shaped
- severed
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- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C17/00—Monitoring; Testing ; Maintaining
- G21C17/017—Inspection or maintenance of pipe-lines or tubes in nuclear installations
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- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C3/00—Reactor fuel elements and their assemblies; Selection of substances for use as reactor fuel elements
- G21C3/30—Assemblies of a number of fuel elements in the form of a rigid unit
- G21C3/32—Bundles of parallel pin-, rod-, or tube-shaped fuel elements
- G21C3/324—Coats or envelopes for the bundles
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- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C19/00—Arrangements for treating, for handling, or for facilitating the handling of, fuel or other materials which are used within the reactor, e.g. within its pressure vessel
- G21C19/14—Arrangements for treating, for handling, or for facilitating the handling of, fuel or other materials which are used within the reactor, e.g. within its pressure vessel characterised by their adaptation for use with horizontal channels in the reactor core
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- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C19/00—Arrangements for treating, for handling, or for facilitating the handling of, fuel or other materials which are used within the reactor, e.g. within its pressure vessel
- G21C19/20—Arrangements for introducing objects into the pressure vessel; Arrangements for handling objects within the pressure vessel; Arrangements for removing objects from the pressure vessel
- G21C19/207—Assembling, maintenance or repair of reactor components
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E30/00—Energy generation of nuclear origin
- Y02E30/30—Nuclear fission reactors
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- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- General Engineering & Computer Science (AREA)
- High Energy & Nuclear Physics (AREA)
- Monitoring And Testing Of Nuclear Reactors (AREA)
- Automatic Assembly (AREA)
- Paper (AREA)
- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
Abstract
A calandria tube, a pressure tube, and first and second end fittings joined to opposing end portions of the pressure tube, are removed from the calandria of a nuclear reactor by first cutting through the pressure tube inboard of each of first and second bell shaped end portions of the calandria tube to form a main pressure tube portion between first and second severed pressure tube end portions. The first and second end fittings together with the respective joined first and second severed pressure tube end portions are removed. The calandria tube is cut outboard of the main pressure tube portion and inboard of the second bell shaped end portion to form a main calandria tube portion, and a severed calandria tube end portion. The main calandria tube portion together with the main pressure tube portion are then removed from the calandria. The severed calandria tube end portion is also removed from the calandria.
Description
CWC-'287 METHOD FOR REMOVAL OF PRESSURE TUBES AND CALANDRIA TUBES
FROM A NUCLEAR REACTOR
The present invention relates to a method of removing irradiated components from a nuclear reactor. In particular, the method relates to the removal of a main calandria tube portion together with a main pressure tube portion contained inside the calandria tube.
Background CanduTM type nuclear reactors typically require refurbishment after about 30 years of service. This refurbishment can double the life of the reactor and typically involves a retubing of the calandria. This retubing process involves the removal of the end fittings and their associated components, the removal of the pressure tube, and the removal of the calandria tube surrounding the pressure tube and some of its associated components. Also spacers required to maintain the spacing between the horizontally and co-axially extending pressure tube and calandria tube are removed. Because these parts are radioactive, the removed parts are typically placed in shielded flasks located in the containment vault. It is also known to volume reduce the larger parts by a chipper located in the reactor containment vault.
The removal process for these fuel channel components from the calandria involves making first cuts to separate the end fittings from the pressure tube outboard of the calandria core within the lattice tube. These first cuts are typically made from the inside of the fuel channel through the pressure tube at a location inboard of the joint of the end fitting and pressure tube such that no part of the end fitting is severed.
Alternatively, the cuts may be made at the location of the joint of the pressure tube to the end fitting or slightly outboard of this joint through both the pressure tube and end fitting. However, in all instances, the cut is made outboard of the end shield inner tube sheet bores and within the lattice tube of the calandria. Subsequent to these cuts, the end fittings are removed from the calandria with or without pressure tube stub portions depending on where the cut is made. Next the pressure tube is typically removed from the calandria tube through one of the end shield lattice tubes of the - -CWC:287 calandria. When the pressure tube is removed, it is highly radiated and is placed into a shielded flask. A bung is then moved through the calandria tube to remove any remaining garter springs into a flask.
The next step is to remove the calandria tube. The calandria tube has opposing bell shaped end portions which extend from the calandria core slightly into the opposing end shields of the calandria. The outer edges of the bell shaped end portions of the calandria tube extend part of the way into the inner tube sheet bore.
These bell shaped end portions are held in place by calandria tube inserts.
The calandria tube insert is a ring member which is inserted inside the calandria tube at each of the bell shaped end portions and is roll formed outwardly to provide an interference fit between the bell shaped end portions of the calandria tube and the corresponding tube sheet bore. The calandria tube insert is removed by inserting a heating coil through the lattice tube sheet bore adjacent the insert and then shock heating the insert. When the insert cools down after heating, it contracts to a diameter less than its rolled out diameter and may be removed from the tube sheet bore and out through the lattice tube. Once both calandria tube inserts are freed, the calandria tube may be freed from the tube sheet bores and pulled/pushed out through one lattice tube in one of the end shields.
This process involves separate removal steps for the pressure tube, the calandria tube, calandria tube inserts, and garter springs which take time in the retubing process. Further these separate removal steps require separate collection/containment of the pressure tubes from the calandria tubes.
Moreover, care must be taken in the removal of both the bell shaped end portions of the calandria tube passing through the same tube sheet bore in one of the end shields of the calandria in order to maintain within acceptable limits the risk of damaging the inner and outer tube sheets, tube sheet bore and lattice tube of the calandria.
Brief Description The present invention relates to a method of removing irradiated components from a nuclear reactor. In particular, the method relates to the removal of a main calandria tube portion together with a main pressure tube portion contained inside the calandria tube.
FROM A NUCLEAR REACTOR
The present invention relates to a method of removing irradiated components from a nuclear reactor. In particular, the method relates to the removal of a main calandria tube portion together with a main pressure tube portion contained inside the calandria tube.
Background CanduTM type nuclear reactors typically require refurbishment after about 30 years of service. This refurbishment can double the life of the reactor and typically involves a retubing of the calandria. This retubing process involves the removal of the end fittings and their associated components, the removal of the pressure tube, and the removal of the calandria tube surrounding the pressure tube and some of its associated components. Also spacers required to maintain the spacing between the horizontally and co-axially extending pressure tube and calandria tube are removed. Because these parts are radioactive, the removed parts are typically placed in shielded flasks located in the containment vault. It is also known to volume reduce the larger parts by a chipper located in the reactor containment vault.
The removal process for these fuel channel components from the calandria involves making first cuts to separate the end fittings from the pressure tube outboard of the calandria core within the lattice tube. These first cuts are typically made from the inside of the fuel channel through the pressure tube at a location inboard of the joint of the end fitting and pressure tube such that no part of the end fitting is severed.
Alternatively, the cuts may be made at the location of the joint of the pressure tube to the end fitting or slightly outboard of this joint through both the pressure tube and end fitting. However, in all instances, the cut is made outboard of the end shield inner tube sheet bores and within the lattice tube of the calandria. Subsequent to these cuts, the end fittings are removed from the calandria with or without pressure tube stub portions depending on where the cut is made. Next the pressure tube is typically removed from the calandria tube through one of the end shield lattice tubes of the - -CWC:287 calandria. When the pressure tube is removed, it is highly radiated and is placed into a shielded flask. A bung is then moved through the calandria tube to remove any remaining garter springs into a flask.
The next step is to remove the calandria tube. The calandria tube has opposing bell shaped end portions which extend from the calandria core slightly into the opposing end shields of the calandria. The outer edges of the bell shaped end portions of the calandria tube extend part of the way into the inner tube sheet bore.
These bell shaped end portions are held in place by calandria tube inserts.
The calandria tube insert is a ring member which is inserted inside the calandria tube at each of the bell shaped end portions and is roll formed outwardly to provide an interference fit between the bell shaped end portions of the calandria tube and the corresponding tube sheet bore. The calandria tube insert is removed by inserting a heating coil through the lattice tube sheet bore adjacent the insert and then shock heating the insert. When the insert cools down after heating, it contracts to a diameter less than its rolled out diameter and may be removed from the tube sheet bore and out through the lattice tube. Once both calandria tube inserts are freed, the calandria tube may be freed from the tube sheet bores and pulled/pushed out through one lattice tube in one of the end shields.
This process involves separate removal steps for the pressure tube, the calandria tube, calandria tube inserts, and garter springs which take time in the retubing process. Further these separate removal steps require separate collection/containment of the pressure tubes from the calandria tubes.
Moreover, care must be taken in the removal of both the bell shaped end portions of the calandria tube passing through the same tube sheet bore in one of the end shields of the calandria in order to maintain within acceptable limits the risk of damaging the inner and outer tube sheets, tube sheet bore and lattice tube of the calandria.
Brief Description The present invention relates to a method of removing irradiated components from a nuclear reactor. In particular, the method relates to the removal of a main calandria tube portion together with a main pressure tube portion contained inside the calandria tube.
- 2 -Advantage is found by removing the main pressure tube portion with the main calandria tube portion in one operation due to the less time it takes to remove both these components together than removing each component one at a time.
Another advantage associated with the removal of the main calandria tube portion together with the main pressure tube portion is that the garter springs or spacers located between the calandria tube and the pressure tube are also removed at the same time. This eliminates the step of moving a bung along the calandria tube to remove the spaces. Moreover, any FROB (flow restricting outlet bundle) placed in the pressure tube during defueling of the reactor prior to retubing are removed with the removal of the main pressure tube portion.
A further advantage associated with the removal of the main calandria tube portion together with the main pressure tube portion is that main calandria tube portion outside wall is typically very clean and so it minimizes the spread of contamination by acting as a sleeve covering the contaminated pressure tube.
Also, during volume reduction, the more ductile calandria tube helps to contain the more brittle pieces of pressure tube that typically fracture during volume reduction.
In accordance with the present invention there is provided a method for removing from a calandria of a nuclear reactor a calandria tube, a pressure tube normally located co-axially within the calandria tube, and first and second end fittings joined to opposing end portions of the pressure tube. The method comprises the steps of:
a) severing the pressure tube inboard of each of first and second bell shaped end portions of the calandria tube to form a main pressure tube portion between first and second severed pressure tube end portions each still joined with a respective one of the first and second end fittings;
b) removing the first end fitting together with the joined first severed pressure tube end portion from one end shield of the calandria and removing the second end fitting together with the joined second severed pressure tube end portion from another end shield of the calandria;
c) severing the calandria tube outboard of the main pressure tube portion and inboard of the second bell shaped end portion to form a main calandria tube portion,
Another advantage associated with the removal of the main calandria tube portion together with the main pressure tube portion is that the garter springs or spacers located between the calandria tube and the pressure tube are also removed at the same time. This eliminates the step of moving a bung along the calandria tube to remove the spaces. Moreover, any FROB (flow restricting outlet bundle) placed in the pressure tube during defueling of the reactor prior to retubing are removed with the removal of the main pressure tube portion.
A further advantage associated with the removal of the main calandria tube portion together with the main pressure tube portion is that main calandria tube portion outside wall is typically very clean and so it minimizes the spread of contamination by acting as a sleeve covering the contaminated pressure tube.
Also, during volume reduction, the more ductile calandria tube helps to contain the more brittle pieces of pressure tube that typically fracture during volume reduction.
In accordance with the present invention there is provided a method for removing from a calandria of a nuclear reactor a calandria tube, a pressure tube normally located co-axially within the calandria tube, and first and second end fittings joined to opposing end portions of the pressure tube. The method comprises the steps of:
a) severing the pressure tube inboard of each of first and second bell shaped end portions of the calandria tube to form a main pressure tube portion between first and second severed pressure tube end portions each still joined with a respective one of the first and second end fittings;
b) removing the first end fitting together with the joined first severed pressure tube end portion from one end shield of the calandria and removing the second end fitting together with the joined second severed pressure tube end portion from another end shield of the calandria;
c) severing the calandria tube outboard of the main pressure tube portion and inboard of the second bell shaped end portion to form a main calandria tube portion,
- 3 -and a severed calandria tube end portion wherein the main pressure tube portion is positioned within the main calandria tube portion; and, d) removing from the one end shield of the calandria the main calandria tube portion together with the main pressure tube portion, and removing from the other end shield of the calandria the severed calandria tube end portion.
It should be understood that during the removal step b), the end fittings may be removed in separate steps performed in any order. Further, in step d), the removal of the calandria main tube portion and the severed calandria tube end portion may be removed in separate steps that are performed in any order.
A further advantage is found in the method of the present invention by steps c) and d). Step c) forms a main calandria tube portion and a severed calandria tube end portion. This step together with step d) of removing the main calandria tube portion from one end shield of the calandria and of removing the severed calandria tube end portion from the other end shield of the calandria has the advantage that bell shaped end portions of the calandria tube are removed through different tube sheet bores of different end shields of the calandria compared to the previous processes where both of the bell shaped end portions of the calandria tube pass through the same tube sheet bore of the same end shield. Removing only one of the bell shaped end portions of the calandria tube through a tube sheet bore reduces the risk of damaging the tube sheet bore and the lattice tube associated with the tube sheet bore.
After the removing step b) the method may further include the step of inserting temporary protective sleeves and shield plugs into the calandria from where the first and second end fittings have been removed. These protective sleeves protect the lattice tubes from being damaged upon removal of parts from the calandria.
The method may further comprise the step of removing the protective sleeves from the calandria after the main calandria tube portion and the severed calandria tube end portion have been removed. The shield plugs act to plug the lattice tube between steps in the removal process so as to shield irradiated components still to be removed from the calandria.
The method step b) may further comprises removing from the calandria a first calandria tube insert normally holding the first bell shaped end portion of the calandria tube with the calandria and method step d) may further comprise removing
It should be understood that during the removal step b), the end fittings may be removed in separate steps performed in any order. Further, in step d), the removal of the calandria main tube portion and the severed calandria tube end portion may be removed in separate steps that are performed in any order.
A further advantage is found in the method of the present invention by steps c) and d). Step c) forms a main calandria tube portion and a severed calandria tube end portion. This step together with step d) of removing the main calandria tube portion from one end shield of the calandria and of removing the severed calandria tube end portion from the other end shield of the calandria has the advantage that bell shaped end portions of the calandria tube are removed through different tube sheet bores of different end shields of the calandria compared to the previous processes where both of the bell shaped end portions of the calandria tube pass through the same tube sheet bore of the same end shield. Removing only one of the bell shaped end portions of the calandria tube through a tube sheet bore reduces the risk of damaging the tube sheet bore and the lattice tube associated with the tube sheet bore.
After the removing step b) the method may further include the step of inserting temporary protective sleeves and shield plugs into the calandria from where the first and second end fittings have been removed. These protective sleeves protect the lattice tubes from being damaged upon removal of parts from the calandria.
The method may further comprise the step of removing the protective sleeves from the calandria after the main calandria tube portion and the severed calandria tube end portion have been removed. The shield plugs act to plug the lattice tube between steps in the removal process so as to shield irradiated components still to be removed from the calandria.
The method step b) may further comprises removing from the calandria a first calandria tube insert normally holding the first bell shaped end portion of the calandria tube with the calandria and method step d) may further comprise removing
- 4 -from the calandria a second calandria tube insert normally holding the second bell shaped end portion of the calandria tube with the calandria. These two removing steps may each respectively comprise first freeing or disjoining of the first and second calandria tube inserts from their respective first and second bell shaped end portions of the calandria tube. The first calandria tube insert may then be removed either separately or together with the removal of the main calandria tube portion and the main pressure tube portion. Also, the second calandria tube insert, once freed or disjoined from the second bell shaped end portion of the calandria tube, may then be removed either separately or together with the removal of the severed calandria tube end portion Brief Description of the Drawings For a better understanding of the nature and objects of the present invention reference may be had by way of example to the accompanying diagrammatic drawings in which:
Figure 1 is a schematic of a nuclear reactor assembly in which method of the present invention may be performed;
Figure 2 is an enlarged sectioned view one of the fueling channels shown in Figure 1;
Figure 3 is an enlarged sectioned view of the fueling channel of Figure 2 with some fuel channel components removed; and, Figure 4 is a flow-chart outlining a detailed process for the removal of components of one of the fuel channels shown in the calandria of Figure 1.
Detailed Description The present invention relates to a method of removing irradiated components from a nuclear reactor. In particular, the method relates to the removal of a main calandria tube portion together with a main pressure tube portion contained inside the calandria tube during an outage where the fuel and heavy water has been removed from the calandria environment.
Referring to Figure 1 there is shown schematically a nuclear reactor assembly 8 of the CanduTM type. The reactor 8 comprises a calandria 10 that has first and
Figure 1 is a schematic of a nuclear reactor assembly in which method of the present invention may be performed;
Figure 2 is an enlarged sectioned view one of the fueling channels shown in Figure 1;
Figure 3 is an enlarged sectioned view of the fueling channel of Figure 2 with some fuel channel components removed; and, Figure 4 is a flow-chart outlining a detailed process for the removal of components of one of the fuel channels shown in the calandria of Figure 1.
Detailed Description The present invention relates to a method of removing irradiated components from a nuclear reactor. In particular, the method relates to the removal of a main calandria tube portion together with a main pressure tube portion contained inside the calandria tube during an outage where the fuel and heavy water has been removed from the calandria environment.
Referring to Figure 1 there is shown schematically a nuclear reactor assembly 8 of the CanduTM type. The reactor 8 comprises a calandria 10 that has first and
- 5 -second end shields 12, 14 (see Figure 2). While only one end shield 12 is shown in Figure 1, it should be understood that other end shield 14 is located on the opposite face of the calandria 10 to end shield 12 and both end shields 12, 14 are shown in Figures 2 and 3. The end shields 12, 14 each comprise inner and outer tube sheet 16 and 18. The end shields 12, 14 respectively have corresponding series of lattice tubes 22, 24 that extend between the inner tube sheet bore 16 and the outer tube sheet bore 18. Corresponding ones of the lattice tubes 22, 24 are aligned (Figure 2). It should be understood that in the calandria 10 there may be as many as 480 tube lattice tubes in each of the end shields 12, 14. Between the inner and outer tube sheet walls 16, 18 is shielding material shown in the drawing in the form of steel balls 20.
Calandria tubes 26 extend horizontally across the core 28 of the calandria 10 between the end shields 12, 14. The calandria tubes 26 are each axially aligned with a corresponding one of the first and second lattice tubes 22, 24 of end shields 12, 14.
As seen in Figures 2 and 3, the calandria tube 26 has opposing first and second bell shaped end portions 40 and 42 which have an outside diameter adapted to fit into the tube sheet bores 22a and 24a of the inner tube sheet 16. The tube sheet bores 22a and 24a connect with the lattice tubes 22, 24. The outside diameter of the bell shaped end portions 40 and 42 is slightly less than the inside diameter of the tube sheet bores 22a, 24a. The bell shaped end portions 40, 42 are positioned to extend into the tube sheet bores 22a, 24a adjacent the inner tubes sheets 16. Calandria tube inserts 44 are located within the tube sheet bores 22a, 24a to hold the bell shaped end portions 40, 42 in interference fit with the inside walls of the tube sheet bores 24a, 26a.
The calandria tube insert 44 comprises a ring inserted within the end of the bell shaped portions 40, 42 and roll formed outwardly thereof to force an interference fit between the bell shaped end portions 40, 42 and the respective tube sheet bores 22a, 24a.
A pressure tube 30 is co-axially positioned within each of the calandria tubes 26. Spacers or garter springs 32 are located in the annular space 34 between the outside wall of the pressure tube 30 and the inside wall of the calandria tube 26.
The pressure tube 30 has first and second outer end portions 46 and 48 which extend outboard slightly beyond the bell shaped end portions 40, 42 respectively and within the tube sheet bores 22a, 24a. It should be understood that outboard is meant to be closer to the outside of the calandria 10 than the inside centre of the calandria
Calandria tubes 26 extend horizontally across the core 28 of the calandria 10 between the end shields 12, 14. The calandria tubes 26 are each axially aligned with a corresponding one of the first and second lattice tubes 22, 24 of end shields 12, 14.
As seen in Figures 2 and 3, the calandria tube 26 has opposing first and second bell shaped end portions 40 and 42 which have an outside diameter adapted to fit into the tube sheet bores 22a and 24a of the inner tube sheet 16. The tube sheet bores 22a and 24a connect with the lattice tubes 22, 24. The outside diameter of the bell shaped end portions 40 and 42 is slightly less than the inside diameter of the tube sheet bores 22a, 24a. The bell shaped end portions 40, 42 are positioned to extend into the tube sheet bores 22a, 24a adjacent the inner tubes sheets 16. Calandria tube inserts 44 are located within the tube sheet bores 22a, 24a to hold the bell shaped end portions 40, 42 in interference fit with the inside walls of the tube sheet bores 24a, 26a.
The calandria tube insert 44 comprises a ring inserted within the end of the bell shaped portions 40, 42 and roll formed outwardly thereof to force an interference fit between the bell shaped end portions 40, 42 and the respective tube sheet bores 22a, 24a.
A pressure tube 30 is co-axially positioned within each of the calandria tubes 26. Spacers or garter springs 32 are located in the annular space 34 between the outside wall of the pressure tube 30 and the inside wall of the calandria tube 26.
The pressure tube 30 has first and second outer end portions 46 and 48 which extend outboard slightly beyond the bell shaped end portions 40, 42 respectively and within the tube sheet bores 22a, 24a. It should be understood that outboard is meant to be closer to the outside of the calandria 10 than the inside centre of the calandria
- 6 -= CA 02727492 2011-01-14 10. Likewise, inboard is meant to be closer to the inside centre of the calandria 10 than the outside of the calandria 10.
Located outboard of these first and second end portions 46, 48 of the pressure tube 30 are first and second end fittings 50, 52. The end fittings 50, 52 have inner end portions 36 that overlap and are joined to the outer end portions 46, 48 of the pressure tubes 30 by rolled joints 54.
The end fittings 50, 52 respectively extend outwardly of the calandria 10 through the lattice tubes 22, 24 and away from and beyond the outer tube wall 18 of the end shields 12, 14. The end fittings 50, 52 are attached to feeder pipes 56 which allow heavy water coolant to flow through the end fittings, and the pressure tube 30 past fuel bundles (not shown) located in the pressure tube 30 within the calandria core 28 during normal reactor operation. The end fittings 50, 52 each have inserted into them a shield plug 58 and closure plug 60. Journal bearings 62 are positioned within the lattice tubes 22, 24 permitting the end fittings 50, 52 to be moved into the lattice tubes. The end fittings 50, 52 are positioned relative to the outer tube sheet 18 of the end shields 12, 14 by a channel locking and unlocking mechanism 64. Also, a bellows 66 surrounds each of the end fittings 50, 52 adjacent the outer tube sheet 18 and is attached to the outer tube sheet 18. A weld 68 is made between the bellows 66 and each of the end shields 50, 52. In this manner the end fittings 50, 52 are joined with the calandria 10.
Referring to Figure 4 there is shown a detailed flow chart of the process of the present invention for removal the end fittings 50, 52, the pressure tube 30 and the calandria tube 26. It should be understood that while these steps are described with a specific order, changing the order of certain steps may still attain the same result of the present invention. Further, while the steps in the invention relate to the removal of one set of end fittings 50, 52, and the associated pressure tube 30 and calandria tube 26 of one fuel channel, in practice, several or all of the first end fittings 50 and several or all of the second end fittings 52 may be removed from the calandria prior to removal of any of the pressure tubes 30 and calandria tubes 26 from the calandria 10.
Accordingly, each step in the method may be done to each of the fuel channels before performing the next method step to the fuel channel.
Located outboard of these first and second end portions 46, 48 of the pressure tube 30 are first and second end fittings 50, 52. The end fittings 50, 52 have inner end portions 36 that overlap and are joined to the outer end portions 46, 48 of the pressure tubes 30 by rolled joints 54.
The end fittings 50, 52 respectively extend outwardly of the calandria 10 through the lattice tubes 22, 24 and away from and beyond the outer tube wall 18 of the end shields 12, 14. The end fittings 50, 52 are attached to feeder pipes 56 which allow heavy water coolant to flow through the end fittings, and the pressure tube 30 past fuel bundles (not shown) located in the pressure tube 30 within the calandria core 28 during normal reactor operation. The end fittings 50, 52 each have inserted into them a shield plug 58 and closure plug 60. Journal bearings 62 are positioned within the lattice tubes 22, 24 permitting the end fittings 50, 52 to be moved into the lattice tubes. The end fittings 50, 52 are positioned relative to the outer tube sheet 18 of the end shields 12, 14 by a channel locking and unlocking mechanism 64. Also, a bellows 66 surrounds each of the end fittings 50, 52 adjacent the outer tube sheet 18 and is attached to the outer tube sheet 18. A weld 68 is made between the bellows 66 and each of the end shields 50, 52. In this manner the end fittings 50, 52 are joined with the calandria 10.
Referring to Figure 4 there is shown a detailed flow chart of the process of the present invention for removal the end fittings 50, 52, the pressure tube 30 and the calandria tube 26. It should be understood that while these steps are described with a specific order, changing the order of certain steps may still attain the same result of the present invention. Further, while the steps in the invention relate to the removal of one set of end fittings 50, 52, and the associated pressure tube 30 and calandria tube 26 of one fuel channel, in practice, several or all of the first end fittings 50 and several or all of the second end fittings 52 may be removed from the calandria prior to removal of any of the pressure tubes 30 and calandria tubes 26 from the calandria 10.
Accordingly, each step in the method may be done to each of the fuel channels before performing the next method step to the fuel channel.
- 7 -The first step in the process 100 relates to the removal of associated end fitting components comprising the closure plug 60, shield plug 58, the channel locking/unlocking mechanism 64 (Figure 2) and the feeder tubes or piping 56.
At step 102, the pressure tube 30 is severed inboard of each of the first and second bell shaped end portions 40, 42. These locations are shown in Figure 2 generally at 70 which locations are also inboard of the inner tube sheets 16.
It should be understood that the cuts made to the pressure tube may be at locations 70 which are the same distance into the pressure tube 30 from each of its ends or may be at different distances. The cut is made internally by an internal cutting tool cutting through the wall of the pressure tube 30. The tool may enter from one side of the calandria and make both cuts or two tools may be used entering from each side of the calandria to make the cuts. A roll cutting tool is used for severing the pressure tube 30. Alternatively, a milling tool may be used. After these cuts are made, the pressure tube 30 comprises a main portion 72, and severed first and second end portions 74, 76 located adjacent the first and second end shields 12, 14.
At step 104, the weld 68 that secures the bellows 66 with each of the first and second end fittings 50, 52 is cut. It should be understood that step 104 may precede step 102 or alternatively form part of step 100.
At step 106, the end fittings 50, 52 are removed from their respective lattice tubes 22, 24 together with their still joined severed pressure tube end portions 74, 76.
At step 108, protective sleeves 92 and shield plugs 98 (Figure 3) are inserted into the tube sheet bores 22, 24 and secured therein. The shield plugs 98 are inserted to shield the outside of the calandria from irradiated components left inside the calandria or still to be removed from the calandria in subsequent steps. For example, it is envisaged that all the end fittings 50 and 52 may be removed prior to the removal of any other components. Accordingly, the shield plug is inserted to cover each exposed opening after the removal of an end fitting so as to cover this opening while the other end fittings are removed.
At step 110, the shield plug 98 is removed from one of the first lattice tubes and a heating coil is inserted into the first lattice tube 22 adjacent the first tube sheet bore 22a and adjacent the calandria tube insert 44. The heating coil performs a heat shocking treatment of the calandria tube insert 44. The calandria tube insert 44 is
At step 102, the pressure tube 30 is severed inboard of each of the first and second bell shaped end portions 40, 42. These locations are shown in Figure 2 generally at 70 which locations are also inboard of the inner tube sheets 16.
It should be understood that the cuts made to the pressure tube may be at locations 70 which are the same distance into the pressure tube 30 from each of its ends or may be at different distances. The cut is made internally by an internal cutting tool cutting through the wall of the pressure tube 30. The tool may enter from one side of the calandria and make both cuts or two tools may be used entering from each side of the calandria to make the cuts. A roll cutting tool is used for severing the pressure tube 30. Alternatively, a milling tool may be used. After these cuts are made, the pressure tube 30 comprises a main portion 72, and severed first and second end portions 74, 76 located adjacent the first and second end shields 12, 14.
At step 104, the weld 68 that secures the bellows 66 with each of the first and second end fittings 50, 52 is cut. It should be understood that step 104 may precede step 102 or alternatively form part of step 100.
At step 106, the end fittings 50, 52 are removed from their respective lattice tubes 22, 24 together with their still joined severed pressure tube end portions 74, 76.
At step 108, protective sleeves 92 and shield plugs 98 (Figure 3) are inserted into the tube sheet bores 22, 24 and secured therein. The shield plugs 98 are inserted to shield the outside of the calandria from irradiated components left inside the calandria or still to be removed from the calandria in subsequent steps. For example, it is envisaged that all the end fittings 50 and 52 may be removed prior to the removal of any other components. Accordingly, the shield plug is inserted to cover each exposed opening after the removal of an end fitting so as to cover this opening while the other end fittings are removed.
At step 110, the shield plug 98 is removed from one of the first lattice tubes and a heating coil is inserted into the first lattice tube 22 adjacent the first tube sheet bore 22a and adjacent the calandria tube insert 44. The heating coil performs a heat shocking treatment of the calandria tube insert 44. The calandria tube insert 44 is
- 8 -allowed to cool and when it does it contracts to a diameter less than its rolled out diameter thereby freeing or allowing the insert 44 to be disjoined from the first bell shaped end portion 40 of calandria tube 26 and the first tube sheet bore 22a.
It should be understood that while heat shocking is disclosed for freeing the insert 44, any other suitable method may be used, such as, for example, internal cutting of the insert 44.
However, heat shocking is the preferred method because it is considered a faster operation than cutting or machining. Also, heat shocking is a cleaner process because it does not produce any chips or debris that could be caused by machining.
At step 112, the shield plug 98, removed in step 110, is reinserted into the lattice tube 22 because significant time may elapse before further steps are performed at this lattice tube.
At step 114, both shield plugs 98 in lattice tubes 22, 24 are removed. Then a cutting tool inserted through the second lattice tube 24 is moved into the calandria tube 26 inboard of the second bell shaped end portion 42. This location is shown generally at 82 in Figure 3 and is also located outboard of position 96 of the main pressure tube portion 72. Also, Figure 3 shows calandria tube severing location 82 to be outboard of the location 70 where the pressure tube was severed in step 102. The calandria tube 26 is severed at location 82. After the calandria tube 26 is severed, the calandria tube 26 forms a severed calandria tube end portion 84, which includes the second bell shaped end portion 42, and a main calandria tube portion 86, which includes the first bell shaped end portion 40 and most of the length of the calandria tube 26 extending outboard of the second bell shaped end portion 42. Moreover, the main pressure tube portion 72, garter springs 32, and any FROBs in the main pressure tube portion 72 are contained within the main calandria tube portion 86.
At step 116, a tool (not shown), such as, for example an internal gripper tool is moved in a first direction in through the first lattice tube 22 inboard of the first bell shaped end portion 40 to a location generally shown at 88 in Figure 3. The gripping tool is expanded at location 88 to come into contact with the inside wall of the calandria tube and may cause this wall to expand. However, this wall is not expanded to be greater than the outside diameter of the first bell shaped end portion 40. The gripper tool is then moved in a reverse direction out of the first lattice tube 22 pulling with it both the main calandria tube portion 86 together with the pressure tube main
It should be understood that while heat shocking is disclosed for freeing the insert 44, any other suitable method may be used, such as, for example, internal cutting of the insert 44.
However, heat shocking is the preferred method because it is considered a faster operation than cutting or machining. Also, heat shocking is a cleaner process because it does not produce any chips or debris that could be caused by machining.
At step 112, the shield plug 98, removed in step 110, is reinserted into the lattice tube 22 because significant time may elapse before further steps are performed at this lattice tube.
At step 114, both shield plugs 98 in lattice tubes 22, 24 are removed. Then a cutting tool inserted through the second lattice tube 24 is moved into the calandria tube 26 inboard of the second bell shaped end portion 42. This location is shown generally at 82 in Figure 3 and is also located outboard of position 96 of the main pressure tube portion 72. Also, Figure 3 shows calandria tube severing location 82 to be outboard of the location 70 where the pressure tube was severed in step 102. The calandria tube 26 is severed at location 82. After the calandria tube 26 is severed, the calandria tube 26 forms a severed calandria tube end portion 84, which includes the second bell shaped end portion 42, and a main calandria tube portion 86, which includes the first bell shaped end portion 40 and most of the length of the calandria tube 26 extending outboard of the second bell shaped end portion 42. Moreover, the main pressure tube portion 72, garter springs 32, and any FROBs in the main pressure tube portion 72 are contained within the main calandria tube portion 86.
At step 116, a tool (not shown), such as, for example an internal gripper tool is moved in a first direction in through the first lattice tube 22 inboard of the first bell shaped end portion 40 to a location generally shown at 88 in Figure 3. The gripping tool is expanded at location 88 to come into contact with the inside wall of the calandria tube and may cause this wall to expand. However, this wall is not expanded to be greater than the outside diameter of the first bell shaped end portion 40. The gripper tool is then moved in a reverse direction out of the first lattice tube 22 pulling with it both the main calandria tube portion 86 together with the pressure tube main
- 9 -portion 72 and the freed insert 44. The garter springs 32 follow with the removal of the main calandria tube portion. Also any FROBs located in the main pressure tube portion 72 are removed with the main pressure tube portion 72. This gripping location 88 is shown to be outboard of the first bell shaped end portion 40 and inboard of the main pressure tube portion 72. The ends of the main calandria tube portion 86 may then by plugged or capped to contain the main pressure tube portion 72.
The removed components are placed in a shielding flask for removal from the vault.
After these components have been removed from the lattice tube 22, the shield plugs 98 are again reinserted into each of the lattice tubes 22, 24.
It should also be understood that in order to facilitate the removal of the main calandria tube portion 86 and the pressure tube portion 72, another tool may extend in through the second tube sheet bore 24 and may push the main calandria tube portion 86 out through the first tube sheet bore 22a. This pushing tool may also assist in supporting the main calandria tube portion 86 as it is pulled and pushed out of tube sheet bore 22a together with the main pressure tube portion 72. It should be understood that a significantly large force will be required to release the first bell shaped end portion 40 out of interference fit with the first tube sheet bore 22a even though the first calandria tube insert 44 has been freed. However, once the interference fit is freed, the force required to move the main calandria tube portion 86 and the pressure tube main portion 72 through the first tube sheet bore 22a and out the first lattice tube 22 is reduced considerably.
It should be understood that in an alternative method, the freed insert 44 may be removed after it has been freed from the first bell shaped end portion 40 prior to the removal step 116.
At step 118 the shield plug 98 is removed from the second lattice tube 24.
Next, the calandria tube insert 44 forcing the interference fit between the second bell shaped end portion 42 of the severed calandria tube end portion 84 and the second tube sheet bore 24 is freed or disjoined. The calandria tube insert 44 is removed in a similar manner as previously described in that a heating coil is inserted into the second tube sheet bore 24 in the vicinity of the calandria tube insert 44 and the inner tube sheet bore 24a. The calandria tube insert 44 undergoes a shock heating process.
The removed components are placed in a shielding flask for removal from the vault.
After these components have been removed from the lattice tube 22, the shield plugs 98 are again reinserted into each of the lattice tubes 22, 24.
It should also be understood that in order to facilitate the removal of the main calandria tube portion 86 and the pressure tube portion 72, another tool may extend in through the second tube sheet bore 24 and may push the main calandria tube portion 86 out through the first tube sheet bore 22a. This pushing tool may also assist in supporting the main calandria tube portion 86 as it is pulled and pushed out of tube sheet bore 22a together with the main pressure tube portion 72. It should be understood that a significantly large force will be required to release the first bell shaped end portion 40 out of interference fit with the first tube sheet bore 22a even though the first calandria tube insert 44 has been freed. However, once the interference fit is freed, the force required to move the main calandria tube portion 86 and the pressure tube main portion 72 through the first tube sheet bore 22a and out the first lattice tube 22 is reduced considerably.
It should be understood that in an alternative method, the freed insert 44 may be removed after it has been freed from the first bell shaped end portion 40 prior to the removal step 116.
At step 118 the shield plug 98 is removed from the second lattice tube 24.
Next, the calandria tube insert 44 forcing the interference fit between the second bell shaped end portion 42 of the severed calandria tube end portion 84 and the second tube sheet bore 24 is freed or disjoined. The calandria tube insert 44 is removed in a similar manner as previously described in that a heating coil is inserted into the second tube sheet bore 24 in the vicinity of the calandria tube insert 44 and the inner tube sheet bore 24a. The calandria tube insert 44 undergoes a shock heating process.
- 10 -After the calandria tube insert 44 has been heated it is allowed to cool thereby contracting in diameter to a diameter less than its rolled out diameter.
At step 120, the shield plug removed in step 118, is reinserted into the second lattice tube 24 because significant time may elapse before further steps are performed at this lattice tube.
At step 122, the same or another gripping tool (not shown) is inserted through the second lattice tube 24 into a position outboard of the second bell shaped end portion 42 of the severed calandria tube end portion 84 which position is generally shown at 90 in Figure 3 and is outboard of the calandria tube severing location 82.
The tool is expanded to grip the severed calandria tube end portion 84 to a diameter that is less then the outside diameter of the second bell shaped end portion 42. The gripper tool is moved in a direction outwardly of the second tube sheet bore 24 to remove the severed calandria tube end portion 84 and its associated freed up calandria tube insert 44 from the calandria 10. Similar removed forces to those mentioned for the removal of the first calandria tube insert are used.
It should be understood that alternatively, the calandria tube insert 44 in lattice tube 24 may be removed immediately after it is freed calandria tube in step 118.
Next at step 124, the shield plug 98 is reinserted into the lattice tube 24.
It should be understood that in the removal of all of these parts from the calandria, these parts are placed into shielding flasks and volume reduced as part of the retubing/refurbishing process.
It should be understood that while the present method does not relate to the removal and replacement of the journal bearings 62 in the lattice tubes 22, 24, should these bearing need to be replaced, the bearings can be removed at any appropriate stage in the method of the present invention.
Also, while the locations 70 for the severing of the pressure tube 30 are believed to provide sufficient space for the remaining steps in the method to be completed, it is envisaged that should these severing locations not provide sufficient space, then the main pressure tube portion 72 may be moveable axially in either direction within the main calandria tube portion 86 to facilitate the heat shocking of the calandria tube insert 44 at the first bell shaped end portion 40 and to facilitate the severing of the calandria tube.
At step 120, the shield plug removed in step 118, is reinserted into the second lattice tube 24 because significant time may elapse before further steps are performed at this lattice tube.
At step 122, the same or another gripping tool (not shown) is inserted through the second lattice tube 24 into a position outboard of the second bell shaped end portion 42 of the severed calandria tube end portion 84 which position is generally shown at 90 in Figure 3 and is outboard of the calandria tube severing location 82.
The tool is expanded to grip the severed calandria tube end portion 84 to a diameter that is less then the outside diameter of the second bell shaped end portion 42. The gripper tool is moved in a direction outwardly of the second tube sheet bore 24 to remove the severed calandria tube end portion 84 and its associated freed up calandria tube insert 44 from the calandria 10. Similar removed forces to those mentioned for the removal of the first calandria tube insert are used.
It should be understood that alternatively, the calandria tube insert 44 in lattice tube 24 may be removed immediately after it is freed calandria tube in step 118.
Next at step 124, the shield plug 98 is reinserted into the lattice tube 24.
It should be understood that in the removal of all of these parts from the calandria, these parts are placed into shielding flasks and volume reduced as part of the retubing/refurbishing process.
It should be understood that while the present method does not relate to the removal and replacement of the journal bearings 62 in the lattice tubes 22, 24, should these bearing need to be replaced, the bearings can be removed at any appropriate stage in the method of the present invention.
Also, while the locations 70 for the severing of the pressure tube 30 are believed to provide sufficient space for the remaining steps in the method to be completed, it is envisaged that should these severing locations not provide sufficient space, then the main pressure tube portion 72 may be moveable axially in either direction within the main calandria tube portion 86 to facilitate the heat shocking of the calandria tube insert 44 at the first bell shaped end portion 40 and to facilitate the severing of the calandria tube.
- 11 -CWC1287 =
While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modifications within the scope of the present invention as disclosed herein.
While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modifications within the scope of the present invention as disclosed herein.
- 12 -
Claims (19)
1. A method for removing from a calandria of a nuclear reactor a calandria tube, a pressure tube normally located co-axially within the calandria tube, and first and second end fittings joined to opposing end portions of the pressure tube, the method comprising the steps of:
a) severing the pressure tube inboard of each of first and second bell shaped end portions of the calandria tube to form a main pressure tube portion between first and second severed pressure tube end portions each still joined with a respective one of the first and second end fittings;
b) removing the first end fitting together with the joined first severed pressure tube end portion from a first end shield of the calandria and removing the second end fitting together with the joined second severed pressure tube end portion from a second end shield of the calandria;
c) severing the calandria tube outboard of the main pressure tube portion and inboard of the second bell shaped end portion to form a main calandria tube portion and a severed calandria tube end portion wherein the main pressure tube portion is positioned within the main calandria tube portion;
d) removing from the first end shield of the calandria the main calandria tube portion together with the main pressure tube portion, and removing from the second end shield of the calandria the severed calandria tube end portion.
a) severing the pressure tube inboard of each of first and second bell shaped end portions of the calandria tube to form a main pressure tube portion between first and second severed pressure tube end portions each still joined with a respective one of the first and second end fittings;
b) removing the first end fitting together with the joined first severed pressure tube end portion from a first end shield of the calandria and removing the second end fitting together with the joined second severed pressure tube end portion from a second end shield of the calandria;
c) severing the calandria tube outboard of the main pressure tube portion and inboard of the second bell shaped end portion to form a main calandria tube portion and a severed calandria tube end portion wherein the main pressure tube portion is positioned within the main calandria tube portion;
d) removing from the first end shield of the calandria the main calandria tube portion together with the main pressure tube portion, and removing from the second end shield of the calandria the severed calandria tube end portion.
2. The method of claim 1 wherein step a) comprises severing the pressure tube in two separate cutting steps, step b) comprises removing the first and second end fittings in two separate removal steps, and step d) comprises removing the main calandria tube portion and the severed calandria tube portion in separate steps.
3. The method of claim 1 wherein after step b), the method further comprises the step of inserting temporary protective sleeves and removable shield plugs into the calandria from where the first and second end fittings have been removed.
4. The method of claim 3 further comprising the step of removing the protective sleeves from the calandria after the main calandria tube portion and the severed calandria tube end portion have been removed.
5. The method of any one of claims 1 to 4 wherein step b) further comprises removing from the calandria a first calandria tube insert, normally holding the first bell shaped end portion of the calandria tube with the calandria, together with the main calandria tube portion and the main pressure tube portion and step d) further comprises removing from the calandria a second calandria tube insert, normally holding the second bell shaped end portion of the calandria tube with the calandria, together with the severed calandria tube end portion.
6. The method of claim 5 wherein prior to steps b) and d) each of the first and second calandria tube inserts are respectively disjoined from the first and second bell shaped end portions of the calandria tube.
7. The method of claim 1 further comprising the step e), of prior to step d), removing from the calandria a first calandria tube insert that normally holds the first bell shaped end portion of the calandria tube with the calandria, and further comprises the step f) of, prior to step d), removing from the calandria a second calandria tube insert that normally holds the second bell shaped end portion of the calandria tube with the calandria.
8. The method of claim 7 wherein prior each of the first and second calandria tube inserts are respectively disjoined from the first and second bell shaped end portions of the calandria tube respectively prior to steps e) and f).
9. The method of claim 1 wherein cuts made to sever the pressure tube to form the main pressure tube portion and the first and second severed pressure tube end portions are made by an internal roll cutting tool.
10. The method of claim 1 wherein the severing of the calandria tube in step c) is made with an internal roll cutting tool.
11. The method of claim 1 wherein step d) is performed by expandable gripping tool that each attach to inner walls of the calandria tube main portion and the calandria tube severed portion respectively inboard of the first and second bell shaped end portions and expands the inner walls to a diameter less than that of the first and second bell shaped end portions.
12. A method for removing a calandria tube and a pressure tube from a nuclear reactor calandria wherein the calandria comprises first and second spaced apart end shields each having inner and outer tube sheets and the calandria comprises aligned first and second lattice tubes respectively extending through the first and second end shields between the inner and outer tube sheets, the calandria tube is aligned with the first and second tube lattice tubes and extends horizontally within the calandria between the first and second end shields, the calandria tube has opposing first and second bell shaped end portions respectively joined by first and second calandria tube inserts with the first and second end shields adjacent a bore in the inner tube sheet, the pressure tube is co-axially positioned within the calandria tube by garter springs and the pressure tube has first and second outer end portions that respectively extend through the first and second bell shaped end portions of the calandria tube, first and second end fittings respectively extend within and out from the first and second lattice tubes away from the outer tube sheet and are joined with the calandria outside of the first and second tube sheet bores, the first and second end fittings have inner end portions that respectively overlap and join with the first and second outer end portions of the pressure tube, the method comprising the steps of:
a) severing the pressure tube inboard of each of the first and second bell shaped end portions of the calandria tube to form a main pressure tube portion between first and second severed pressure tube end portions, b) disjoining the first and second end fittings from the calandria and respectively removing from the first and second lattices tubes of the calandria the first and second end fittings together with the respectively joined first and second severed pressure tube portions;
c) disjoining the first calandria tube insert from the first bell shaped end portion of the calandria tube;
d) severing the calandria tube outboard of the main pressure tube portion and inboard of the second bell shaped end portion to form a main calandria tube portion, and a severed calandria tube end portion that comprises at least in part the second bell shaped end portion and wherein the main pressure tube portion is positioned within the main calandria tube portion;
e) removing together the first calandria tube insert, the main calandria tube portion, and the main pressure tube portion through the first lattice tube of the first end shield;
f) disjoining the second calandria tube insert from the second bell shaped end portion of the calandria tube; and, g) removing the severed calandria tube end portion together with the second calandria tube insert through the second lattice tube of the second end shield.
a) severing the pressure tube inboard of each of the first and second bell shaped end portions of the calandria tube to form a main pressure tube portion between first and second severed pressure tube end portions, b) disjoining the first and second end fittings from the calandria and respectively removing from the first and second lattices tubes of the calandria the first and second end fittings together with the respectively joined first and second severed pressure tube portions;
c) disjoining the first calandria tube insert from the first bell shaped end portion of the calandria tube;
d) severing the calandria tube outboard of the main pressure tube portion and inboard of the second bell shaped end portion to form a main calandria tube portion, and a severed calandria tube end portion that comprises at least in part the second bell shaped end portion and wherein the main pressure tube portion is positioned within the main calandria tube portion;
e) removing together the first calandria tube insert, the main calandria tube portion, and the main pressure tube portion through the first lattice tube of the first end shield;
f) disjoining the second calandria tube insert from the second bell shaped end portion of the calandria tube; and, g) removing the severed calandria tube end portion together with the second calandria tube insert through the second lattice tube of the second end shield.
13. The method of claim 12 wherein the order of steps c) and d) is reversed.
14. The method of claim 12 or 13, wherein the order of steps c) and e) follow steps 0 and g).
15. The method of claim 12 wherein step a) comprises cutting the pressure tube in two separate cutting steps and step b) comprises removing the first and second end fittings in two separate removal steps.
16. The method of claim 12 wherein after the step b), the method further including the step of inserting temporary protective sleeves and shield plugs into the first and second lattice tubes from where the first and second end fittings have been removed.
17. The method of claim 12 wherein the disjoining the end fittings from the calandria of step b) further comprises cutting through a weld joint between each of the first and second end fittings and a respective first and second bellows respectively surrounding the first and second end fittings and respectively secured with the first and second end shields.
18. The method of claim 12 wherein the cutting of the calandria tube in step c) is made with an internal roll cutting tool.
19. The method of claim 12 wherein steps e) and g) are performed by an expandable gripping tools that attach to inner walls of the calandria tube main portion and calandria tube severed portion respectively inboard of the first and second bell shaped end portions and the tools expanding the inner wall of the calandria tube to a diameter less than that of the bell shaped end portions.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2727492A CA2727492C (en) | 2011-01-14 | 2011-01-14 | Method for removal of pressure tubes and calandria tubes from a nuclear reactor |
| ROA201200013A RO128332B1 (en) | 2011-01-14 | 2012-01-11 | Method for removal of pressure tubes and calandria tubes from a nuclear reactor |
| ARP120100087A AR084827A1 (en) | 2011-01-14 | 2012-01-11 | METHOD FOR EXTRACTION OF PRESSURE TUBES AND CALANDRIA TUBES FROM A NUCLEAR REACTOR |
| KR1020120004243A KR101859359B1 (en) | 2011-01-14 | 2012-01-13 | Method for removal of pressure tubes and calandria tubes from a nuclear reactor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2727492A CA2727492C (en) | 2011-01-14 | 2011-01-14 | Method for removal of pressure tubes and calandria tubes from a nuclear reactor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2727492A1 CA2727492A1 (en) | 2012-07-14 |
| CA2727492C true CA2727492C (en) | 2014-09-09 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2727492A Active CA2727492C (en) | 2011-01-14 | 2011-01-14 | Method for removal of pressure tubes and calandria tubes from a nuclear reactor |
Country Status (4)
| Country | Link |
|---|---|
| KR (1) | KR101859359B1 (en) |
| AR (1) | AR084827A1 (en) |
| CA (1) | CA2727492C (en) |
| RO (1) | RO128332B1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20200019886A (en) * | 2017-06-23 | 2020-02-25 | 캔두 에너지 인코포레이티드 | Systems and methods for aligning reactor tubes and end fittings using tube geometry |
| US11417436B2 (en) * | 2018-07-13 | 2022-08-16 | Korea Hydro & Nuclear Power Co., Ltd. | Apparatus for decommissioning heavy-water reactor facilities and method for decommissioning heavy-water reactor facilities |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RO134275A2 (en) * | 2017-06-23 | 2020-06-30 | Candu Energy Inc. | System and method for aligning nuclear reactor tubes and end fittings using tube rotation |
| RO133588B1 (en) * | 2017-06-23 | 2024-03-29 | Candu Energy Inc. | Apparatus and method for localization of calandria tube |
| KR102025875B1 (en) * | 2018-07-13 | 2019-09-26 | 한국수력원자력 주식회사 | Method for decommissioning pressure heavy water reactor facilities |
| KR102116037B1 (en) | 2018-09-21 | 2020-05-27 | 한국수력원자력 주식회사 | Collecting apparatus of shielding ball for heavy water reactor |
| KR102185335B1 (en) * | 2019-01-18 | 2020-12-01 | 한국수력원자력 주식회사 | Aparatus and method for dismantling for heavy water reactor facilities |
| CN113140340B (en) * | 2021-03-24 | 2022-07-26 | 中国核电工程有限公司 | Design method for integrity test of advanced pressurized water reactor nuclear power plant containment |
| WO2023164783A1 (en) * | 2022-03-04 | 2023-09-07 | Ats Automation Tooling Systems Inc. | Systems and method for combined removal of a calandria tube and a pressure tube |
| KR102475811B1 (en) * | 2022-10-06 | 2022-12-08 | (주)한국원자력 엔지니어링 | Reprocessing method of sludge paraffin solids and Paraffin separator used therefor |
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| CA2026467A1 (en) | 1990-09-28 | 1992-03-29 | Ralph G. Moyer | Intertube thermal conductance rate limiting device |
| US6599067B2 (en) | 2001-03-26 | 2003-07-29 | Atomic Energy Of Canada Limited | Apparatus for removing pressure tubes |
| JP4124643B2 (en) | 2002-12-27 | 2008-07-23 | 三井住友建設株式会社 | Reactor dismantling and removal methods |
| JP4167198B2 (en) | 2004-03-31 | 2008-10-15 | 三井住友建設株式会社 | Reactor body disassembly method |
-
2011
- 2011-01-14 CA CA2727492A patent/CA2727492C/en active Active
-
2012
- 2012-01-11 AR ARP120100087A patent/AR084827A1/en unknown
- 2012-01-11 RO ROA201200013A patent/RO128332B1/en unknown
- 2012-01-13 KR KR1020120004243A patent/KR101859359B1/en active IP Right Grant
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20200019886A (en) * | 2017-06-23 | 2020-02-25 | 캔두 에너지 인코포레이티드 | Systems and methods for aligning reactor tubes and end fittings using tube geometry |
| KR102601222B1 (en) | 2017-06-23 | 2023-11-09 | 캔두 에너지 인코포레이티드 | Systems and methods for aligning reactor tubes and end fittings using the geometry of the tubes |
| US11417436B2 (en) * | 2018-07-13 | 2022-08-16 | Korea Hydro & Nuclear Power Co., Ltd. | Apparatus for decommissioning heavy-water reactor facilities and method for decommissioning heavy-water reactor facilities |
Also Published As
| Publication number | Publication date |
|---|---|
| AR084827A1 (en) | 2013-06-26 |
| CA2727492A1 (en) | 2012-07-14 |
| RO128332B1 (en) | 2018-07-30 |
| RO128332A2 (en) | 2013-04-30 |
| KR101859359B1 (en) | 2018-05-21 |
| KR20120082831A (en) | 2012-07-24 |
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