Method and apparatus for replacing a sleeve lining a tube in a nuclear reactor pressure vessel from the lower end

Abstract

A method for replacing a damaged sleeve (26) lining a tube (36) passing through a nuclear reactor pressure vessel (10) is provided. The damaged sleeve has an end including a radially enlarged end portion (48), the end portion (48) being configured to rest on a support portion (44) of the tube to retain the damaged sleeve in the tube. The method includes removing the damaged sleeve from the tube; providing a sleeve assembly (62) including a first sleeve (64) having a radially variable end and a retainer (66), the radially variable end being configured to deform between a radially contracted configuration and a radially expanded configuration, the retainer (66) being configured to deform between a mounted configuration and a retained configuration; installing the sleeve assembly in the tube such that the radially variable end of the first sleeve is received by the support portion, the radially variable end being in a radially contracted configuration during installation and in a radially expanded configuration after the sleeve assembly is installed in the tube; and deforming the retainer from the mounted configuration to the retained configuration to retain the radially variable end of the first sleeve in the radially expanded configuration.

Description

[0001] The present disclosure relates generally to methods and apparatus for replacing sleeves lining tubes passing through nuclear reactor pressure vessels, and more particularly to methods and apparatus for replacing thermal sleeves lining control rod drive mechanism (CRDM) nozzles or casings. Background Art

[0002] The reactor vessel closure head (RVCH), such as in Westinghouse reactors, has a thermal sleeve whose primary function is to protect the CRDM nozzle from thermal shock when the thermal control rods are driven out of the core. Over time, the thermal sleeve wears due to vibration and eventually fails. Typically, the RVCH is removed from the vessel and placed on a head rack, and then the CRDM is completely removed and the thermal sleeve replaced.

[0003] FR 2689297 discloses a tool designed to change sleeves without removing the CRD, which tool involves the use of a replacement sleeve comprising an outer flange and an inner flange constituting a support portion of the replacement sleeve.

[0004] PCT / US 18 / 27663 and PCT / US 18 / 27668 disclose methods and apparatus for replacing a CRDM thermal sleeve. SUMMARY OF THE INVENTION

[0006] A method for replacing a damaged sleeve lining a tube passing through a nuclear reactor pressure vessel is provided. The damaged sleeve has an end including a radially enlarged end portion, the end portion being configured to rest on a support portion of the tube to retain the damaged sleeve in the tube. The method comprises: removing the damaged sleeve from the tube; providing a sleeve assembly comprising a first sleeve having a radially variable end and a retainer, the radially variable end being configured to deform between a radially contracted configuration and a radially expanded configuration, the retainer being configured to deform between a mounted configuration and a retained configuration; installing the sleeve assembly in the tube such that the radially variable end of the first sleeve is received by the support portion, the radially variable end being in a radially contracted configuration during installation and in a radially expanded configuration after the sleeve assembly is installed in the tube; and deforming the retainer from the mounted configuration to the retained configuration such that the radially variable end of the first sleeve is retained in the radially expanded configuration.

[0007] In one or more embodiments, the method may include the following features:

[0008] Installation of the sleeve assembly includes inserting the radially variable end of the first sleeve in a radially contracted configuration into the first end of the tube;

[0009] After installation, the radially variable end of the first sleeve is in a radially expanded configuration at the second end of the tube;

[0010] The first end of the tube is the lower end of the tube, and the second end of the tube is the upper end of the tube;

[0011] During installation of the sleeve assembly in the tube, the retainer is a second sleeve retained in the radially variable end of the first sleeve;

[0012] the second sleeve including a radially variable end configured to deform between a radially contracted configuration and a radially expanded configuration;

[0013] The radially variable end of the second sleeve is in a radially contracted configuration in the installed configuration and in a radially expanded configuration in the retained configuration;

[0014] The radially variable end of the first sleeve includes a plurality of first segments circumferentially separated from one another by first grooves, and the radially variable end of the second sleeve includes a plurality of second segments circumferentially separated from one another by second grooves;

[0015] The first segment and the second segment are flexible radially inwardly and radially outwardly;

[0016] deforming the retainer from a mounting configuration to a retaining configuration to retain the radially variable end of the first sleeve in a radially expanded configuration, including engaging the first segment and the second segment with each other;

[0017] each of the first circumferentially spaced segments includes a first radially outwardly extending projection that rests on the support portion after the sleeve assembly is installed in the tube, and each of the second circumferentially spaced segments includes a second radially outwardly extending projection that rests on the support portion after the sleeve assembly is installed in the tube;

[0018] The first protrusions are circumferentially separated from each other by the first grooves, and the second protrusions are circumferentially separated from each other by the second grooves;

[0019] Engaging the first segment and the second segment with each other includes aligning the first segment and the second segment so that each of the first protrusions is received in one of the second grooves and each of the second protrusions is received in one of the first grooves;

[0020] deforming the retainer from a mounting configuration to a retaining configuration to retain the radially variable end of the first sleeve in a radially expanded configuration, including deforming the second segment to force the second protrusions radially outward from one another and pulling the second sleeve downward so that each of the second protrusions is located in one of the first slots and the first and second protrusions are axially aligned with one another;

[0021] Each of the second segments is provided with a protrusion extending radially outwardly from the second segment;

[0022] During installation of the sleeve assembly in the tube and deformation of the retainer from the installation configuration to the retaining configuration, each of the protrusions is received in one of the first grooves;

[0023] The first sleeve includes a funnel at an end thereof opposite to the radially variable end;

[0024] During installation of the sleeve assembly in the tube, the funnel is part of the first sleeve;

[0025] The tube is a control rod drive mechanism nozzle passing through a closure head of the nuclear reactor pressure vessel; and / or

[0026] During installation of the sleeve in the tube, the closure head is separated from the cylindrical shell of the nuclear reactor pressure vessel.

[0027] A control rod drive mechanism thermal sleeve for insertion into a control rod drive mechanism nozzle of a nuclear reactor pressure vessel is also provided.

[0028] The CRDM thermal sleeve includes a first sleeve having a radially variable end configured to deform between a radially contracted configuration and a radially expanded configuration. In the radially expanded configuration, the radially variable end is configured to retain the sleeve in the CRDM nozzle. The first sleeve also includes an opposite end opposite the radially variable end. The opposite end includes a funnel having a frustoconical portion with a maximum diameter edge defining an end edge of the opposite end. The CRDM thermal sleeve also includes a retainer configured to deform between a mounted configuration and a retaining configuration. In the retaining configuration, the retainer is configured to retain the first sleeve in the radially expanded configuration.

[0029] In one or more embodiments, the CRDM thermal sleeve can include the following features:

[0030] The retainer is a second sleeve retained in the radially variable end of the first sleeve in the installed configuration and the retained configuration;

[0031] the second sleeve including a radially variable end configured to deform between a radially contracted configuration and a radially expanded configuration;

[0032] In the installed configuration the second sleeve is in a radially contracted configuration, and in the retained configuration it is in a radially expanded configuration;

[0033] The radially variable end of the first sleeve includes a plurality of first segments circumferentially separated from one another by first grooves, and the radially variable end of the second sleeve includes a plurality of second segments circumferentially separated from one another by second grooves;

[0034] The first segment and the second segment are flexible radially inwardly and radially outwardly;

[0035] the first segment and the second segment being configured to engage one another in the retained configuration of the second sleeve;

[0036] Each of the circumferentially spaced first segments includes a first protrusion extending radially outward, and each of the circumferentially spaced second segments includes a second protrusion extending radially outward;

[0037] the first segment and the second segment being engaged with each other by each of the first protrusions being received in one of the second grooves and each of the second protrusions being received in one of the first grooves;

[0038] Each of the second segments is provided with a protrusion extending radially outwardly from the second segment; and / or

[0039] Each of the protrusions is configured to be received in one of the first slots in the installed configuration and the retained configuration. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The present invention will be described below with reference to the accompanying drawings, in which:

[0041] Figure 1 schematically illustrates a cross-sectional view of a nuclear reactor pressure vessel of a PWR including a plurality of CRDM tube assemblies extending upwardly from the pressure vessel;

[0042] Figure 2 A cross-sectional view of a closure head of a nuclear reactor pressure vessel is shown, showing details of the nozzle and thermal sleeve of a conventional CRDM tube assembly;

[0043] Figure 3 showing a perspective view of the upper end of a thermal sleeve assembly according to an embodiment of the present invention; and

[0044] Figure 4 4a and 4b show different views of a first sleeve according to an embodiment of the present invention;

[0045] Figure 4 c shows a view of a funnel for connection to a first sleeve;

[0046] Figure 5 5a, 5b and 5c show different views of a second sleeve-form retainer according to an embodiment of the present invention;

[0047] Figure 6 a-6e shows the Figure 3-5 c The thermal sleeve assembly is installed in the nozzle;

[0048] Figure 7 shows a perspective view of a compression tool used in accordance with an embodiment of the present invention; and

[0049] Figure 8 A perspective view of a welding tool used in accordance with an embodiment of the present invention is shown. Detailed Description of the Invention

[0051] The present disclosure provides a replacement thermal sleeve, comprising a first sleeve including a funnel at a lower end and a second sleeve forming a retainer for retaining the first sleeve; and a method for replacing a damaged thermal sleeve in a nuclear reactor pressure vessel by engaging the first and second sleeves to lock the first and second sleeves in a CRDM nozzle. After the first and second sleeves engage with each other, the first and second sleeves can be connected by methods such as roller expansion, deformation, or welding.

[0052] Figure 1 A cross-sectional view of a nuclear reactor pressure vessel 10 for a pressurized water reactor (PWR) is schematically shown, the pressure vessel including a plurality of CRDM tube assemblies 12 extending upward from the pressure vessel 10. The pressure vessel 10 includes a RVCH 14 having a hemispherical wall 14a located atop a flange 14b, through which the CRDM tube assemblies 12 extend. The RVCH 14 is removably secured to the top of a cylindrical outer shell 16 via the flange 14b of the RVCH 14, which is secured to the flange 16a of the cylindrical outer shell 16 via studs and nuts. The hemispherical wall 14a includes an outer hemispherical surface 18 facing away from the interior 20 of the pressure vessel 10 and an inner hemispherical surface 22 facing the interior 20. The CRDM tube assemblies 12 extend through the outer hemispherical surface 18 and the inner hemispherical surface 22. During operation of the nuclear reactor, the RVCH 14 is fixed to the top of the cylindrical housing 16. During refueling operations, the RVCH 14 is removed from the cylindrical housing 16.

[0053] Figure 2 A cross-sectional view of the RVCH 14 is shown, showing details of the CRDM tube assembly 12 interrupted by a broken wire. The CRDM tube assembly 12 includes an outer tube in the form of a nozzle 24 permanently fixed in the wall 14a and a thermal sleeve 26 lined in the nozzle 24. The nozzle 24 passes through a corresponding hole formed in the wall 14a and is welded to the wall 14a.

[0054] The CRDM tube assembly 12 is positioned such that a central longitudinally extending axis CA of the CRDM tube assembly 12 extends perpendicularly through the wall 14a. As used herein, the terms axial, radial, and circumferential are used relative to the central axis CA of the CRDM tube assembly 12. The CRDM tube assembly 12 protrudes longitudinally beyond the hemispherical surface 18 such that a first end 28 of the nozzle 24 and a first end 30 of the sleeve 26 are positioned outside the pressure vessel 10. The CRDM tube assembly 12 also protrudes longitudinally beyond the hemispherical surface 22 such that a second end 32 of the nozzle 24 and a second end 34 of the sleeve 26 are positioned within the interior 20 of the pressure vessel 10. The nozzle 24 includes an intermediate portion 36 extending from the first end 28 through the wall 14a to the second end 32, and the sleeve 26 includes an intermediate portion 38 extending from the first end 30 through the wall 14a to the second end 34.

[0055] The first end 28 of the nozzle 24 extends vertically upward farther from the wall 14a than the first end 30 of the sleeve 26. The first end 28 of the nozzle 24 includes a radially enlarged annular portion 40 that is radially thicker than the middle portion 36 of the nozzle 24 and has an outer circumferential surface 40a that is radially farther from the central axis CA than the outer circumferential surface 36a of the middle portion 36. The radially enlarged annular portion 40 includes a lower portion 42 having an inner circumferential surface 42a having the same diameter as the inner circumferential surface 36b of the middle portion 36. Above the lower portion 42, the inner diameter of the enlarged annular portion 40 defines a radially enlarged support portion 44 formed as an annular shoulder having a frustoconical inner circumferential support surface 44a that extends radially away from the inner circumferential surface 42a and extends axially upward to connect with the inner circumferential surface 46a of the upper portion 46 of the enlarged annular portion 40. The upper portion 46 defines a top edge 46 b of the nozzle 24 .

[0056] The first end 30 of the sleeve 26 includes a radially enlarged annular portion 48 that is radially thicker than the intermediate portion 38 of the thermal sleeve 26 and has an outer circumferential surface 48a that is radially farther from the central axis CA than the outer circumferential surface 38a of the intermediate portion 38. The radially enlarged annular portion 48 is supported by the support portion 44 of the radially enlarged annular portion 40 of the nozzle 24. More specifically, the radially enlarged annular portion 48 includes a lower surface 48b that rests perpendicularly on the support surface 44a. Over time, the radially enlarged portion 48 can fail due to the vibrations experienced by the thermal sleeve 26.

[0057] The second end 34 of the sleeve 26 extends vertically downwardly farther from the wall 14a than the second end 32 of the nozzle 24. The second end of the sleeve 26 is formed by a funnel 50 fixed to the intermediate portion 38. The funnel 50 includes a cylindrical portion 50a fixed to the outer circumferential surface 38a of the intermediate portion and a frustoconical portion 50b extending downwardly from the cylindrical portion 50a. The frustoconical portion 50b expands radially as it extends vertically downwardly from the intermediate portion 38. The second end 32 of the nozzle 24 is substantially cylindrical and surrounds a portion of the intermediate portion 38 of the sleeve 26.

[0058] Figure 3 6 shows a perspective view of the upper end 60 of a new or replacement thermal sleeve assembly 62 according to an embodiment of the present invention. The thermal sleeve assembly 62 includes a first sleeve 64 and a second sleeve 66. The first sleeve 64 includes a funnel 72 ( Figure 4 c) The second sleeve 66 forms a holder for holding the first sleeve 64 in the nozzle 24. In a preferred embodiment, the sleeves 64, 66 are both made of metal, more specifically, they may be stainless steel.

[0059] Figure 3 The first sleeve 64 and the second sleeve 66 are shown connected together such that the sleeves 64, 66 are non-rotatably fixed relative to each other and are engaged with each other at their respective upper ends 65, 67. The thermal sleeve assembly 62 is configured in the same manner as the original thermal sleeve 26, except for the difference between the upper end 60 of the thermal sleeve assembly 62 and the upper end 28 of the thermal sleeve 26. More specifically, the first sleeve 64 is configured in the same manner as the original thermal sleeve 26, except for the difference between the upper end 65 of the first sleeve 64 and the upper end 28 of the thermal sleeve 26.

[0060] Figure 4 4a and 4b show different views of the first sleeve 64, Figure 4 c shows a view of the funnel 72 for connection to the first sleeve 64 . Figure 4 a shows a cross-sectional side view of the first sleeve 64, Figure 4 b shows a top view of the first sleeve 64, Figure 4 c shows a cross-sectional side view of the funnel 72 .

[0061] like Figure 4 As shown in Figures 4a and 4b, the upper end 65 of the first sleeve 64 includes a plurality of circumferentially spaced first segments 74 separated from each other by circumferentially spaced first axially extending slots 76 extending upwardly from the cylindrical base 70 of the first sleeve 64. The cylindrical base 70 includes a slot for receiving the second sleeve 66 ( Figure 55a-5c), a top portion 70a of the cylindrical base 96, a middle portion 70b defining the lower end 90 of the first sleeve 64, and a bottom portion 70c. Each segment 74 includes a first lower base end 78 connected to the top portion 70a of the cylindrical base 70 and a longitudinally extending first tine 82 extending axially upward from the lower base end 78. For each first segment 74, at the upper end 65, each first tine 82 is connected to a radially outward first projection 84 that extends radially outward beyond the outer circumferential surface 82a of the corresponding tine 82, such that the outer circumferential surface 84a of each projection 84 is radially farther from the central axis CA than the outer circumferential surface 82a. The radially outward projections 84 form a radially enlarged end portion of the sleeve 64.

[0062] Each protrusion 84 is radially thicker than the tines 82 and the cylindrical base 70. Figure 4 As shown in FIG. 1 , the innermost circumferential surface 84b of each protrusion 84 is substantially the same radial distance from the central axis CA as the inner circumferential surface 82b of the corresponding tine 82. The protrusion 84 is configured to be supported by the support portion 44 of the radially enlarged annular portion 40 of the nozzle 24 ( Figure 2 ). More specifically, each protrusion 84 includes a lower surface 84c configured to be vertically placed on the support surface 44a of the support portion 44 ( Figure 2 ). The protrusions 84 each include a tapered surface 84d, which Figure 4 In the embodiment shown in FIG. a, the projection 84 is in the shape of a semi-truncated cone, extending radially outward from the innermost circumferential surface 84b to the upper surface 84e. Each projection 84 also includes two opposite circumferentially facing side edges 84f, 84g. The tapered surface 84d of each projection 84 extends circumferentially from the first edge 84f of the corresponding projection 84 to the second edge 84g. The outer circumferential surface 84a of each projection 84 has two different outer diameters, defining a portion for accommodating the following reference Figure 5 5a and 5b illustrate the stepped portion 84h of the wings 108, 109.

[0063] Each slot 86 is defined by a circumferentially extending base edge 88a, two axially extending longitudinal edges 88b and 88c, and two side edges 84f and 84g. Base edge 88a is located at the top of top portion 70a of cylindrical base 70, and longitudinal edges 88b and 88c extend axially upward from base edge 88a. A first longitudinal edge 88b extends axially upward from base edge 88a to a corresponding upper side edge 84f of one of protrusions 84, while a second longitudinal edge 88c extends axially upward from base edge 88a to a corresponding side edge 84g of the other protrusion 84. For each slot 86, each edge 88b forms a lateral edge of a tine 82 of one of segments 84, while each edge 88c forms a lateral edge of a tine 82 of the other segment 84. Each edge 88b and 88c extends radially from inner circumferential surface 82b to outer circumferential surface 82a of the corresponding tine 82.

[0064] The first sleeve 64 is configured such that the upper end 65 is configured as a radially variable end that is deformable so that the radius of the radially variable end can be changed. More specifically, the upper end 65 is radially expandable and compressible between a radially contracted configuration in which the upper end 65 has a smaller outer diameter and a radially expanded configuration in which the upper end 65 has a larger outer diameter. More specifically, the segment 74 is configured such that the segment 74 is radially flexible. The segment 74 can be deformed radially inward to orient the upper end 65 into the radially contracted configuration, and can be deformed radially outward to orient the upper end 65 into the radially expanded configuration. In a preferred embodiment, the segment 74 is configured to have sufficient elasticity so that an externally applied radially inward force applied to the segment 74 moves the upper end 65 into the radially contracted configuration, and when the externally applied radially inward force is removed, the structure of the segment 74 generates a radially outward force sufficient to move the upper end 65 from the radially contracted configuration to the radially expanded configuration. In an alternative embodiment, segments 74 are configured to be sufficiently resilient such that an externally applied radially outward force moves upper end 65 to the radially expanded configuration, and when the externally applied radially inward force is removed, the configuration of segments 74 generates a radially inward force sufficient to move upper end 65 from the radially contracted configuration to the radially expanded configuration. In another alternative embodiment, segments 74 are configured such that an externally applied radially inward force is required to move upper end 65 to the radially contracted configuration, and no externally applied radially outward force is required to move upper end 65 to the radially expanded configuration.

[0065] refer to Figure 4 c, with Figure 2 Similar to the funnel 50 shown in FIG, the funnel 72 includes a cylindrical portion 72a configured to be secured to an outer circumferential surface 90a of the lower end 90 of the first sleeve 64 and a frustoconical portion 72b extending downwardly from the cylindrical portion 50a.

[0066] Figure 5 5a, 5b and 5c show different views of a retainer in the form of a second sleeve 66. Figure 5 a shows a cross-sectional side view of the second sleeve 66, Figure 5 b shows a top view of the second sleeve 66, Figure 5 c shows a side view of the bottom of the second sleeve 66 .

[0067] like Figure 5 As shown in Figures 5a and 5b, the upper end 67 of the second sleeve 66 includes a plurality of circumferentially spaced second segments 92 separated from one another by circumferentially spaced, axially extending second slots 94 extending upward from a cylindrical base 96 of the second sleeve 66. The cylindrical base 96 defines a middle portion 98 and a lower end 100 of the second sleeve 66. Each second segment 92 includes a lower base end 102 connected to the top of the middle portion 98 of the second sleeve 66 and a longitudinally extending second tine 104 extending axially upward from the lower base end 102. For each segment 92, at the upper end 67, each second tine 104 is connected to a radially outward second projection 106 that extends radially outward beyond the outer circumferential surface 104a of the corresponding tine 104, such that the outer circumferential surface 106a of each projection 106 is radially farther from the central axis CA than the outer circumferential surface 104a. The radially outward projections 106 form a radially enlarged end portion of the sleeve 66.

[0068] Each protrusion 106 is radially thicker than the tines 104 and the cylindrical base 96. Figure 5 As shown in FIG. 1 , the innermost circumferential surface 106b of each protrusion 106 is substantially the same radial distance from the central axis CA as the inner circumferential surface 104b of the corresponding tine 104. The protrusion 106 is configured to be supported by the support portion 44 of the radially enlarged annular portion 40 of the nozzle 24 ( Figure 2 ). More specifically, each protrusion 106 includes a lower surface 106c configured to be vertically placed on the support surface 44a of the support portion 44 ( Figure 2 ). The protrusions 106 each include a tapered surface 106d, which Figure 4 In the embodiment shown in FIG. a, the projection 106 is in the shape of a semi-truncated cone, extending radially outward from the innermost circumferential surface 106b to the upper surface 106e. Each projection 106 also includes two opposing circumferentially facing side edges 106f and 106g. The tapered surface 106d of each projection 106 extends circumferentially from the first edge 106f of the corresponding projection 106 to the second edge 106g. Each projection 106 is provided with two circumferentially extending wings 108 and 109, which extend circumferentially from opposite sides of the corresponding projection 106. More specifically, each projection 106 includes a first wing 108 extending circumferentially from the first edge 106f and a second wing 109 extending circumferentially from the second edge 106g.

[0069] Each slot 94 is defined by a circumferentially extending base edge 110a, two axially extending, circumferentially facing longitudinal edges 110b, 110c, and two side edges 106f, 106g. Base edge 110a is located at the top of intermediate portion 98 of base 96, and longitudinal edges 110b, 110c extend axially upward from base edge 110a. First longitudinal edge 110b extends axially upward from base edge 110a to a corresponding side edge 106f of one of protrusions 106, and second longitudinal edge 110c extends axially upward from base edge 110a to a corresponding side edge 106g of the other protrusion 106. For each slot 94, each edge 110b forms a lateral edge of a tine 104 of one of segments 92, and each edge 110c forms a lateral edge of both a tine 104 and a protrusion 106 of the other segment 92. The edges 110 b , 110 c each extend radially from the inner circumferential surface 104 b to the outer circumferential surface 104 a of the respective tine 104 , and radially extend from the innermost circumferential surface 106 b to the outer circumferential surface 106 a of the respective protrusion 106 .

[0070] The second sleeve 66 is a retainer configured to deform between an installation configuration and a retention configuration. Specifically, the second sleeve 66 is configured so that the upper end 67 is configured as a radially variable end that is deformable so that the radius of the radially variable end can be changed. More specifically, the upper end 67 is radially expandable and radially compressible between a radially contracted configuration in which the upper end 67 has a smaller outer diameter and a radially expanded configuration in which the upper end 67 has a larger outer diameter. More specifically, the segment 92 is configured so that the segment 92 is radially flexible. In the installation configuration, the second sleeve 66 is in a radially contracted configuration, while in the retention configuration, it is in a radially expanded configuration. The segment 92 can be deformed radially inward to orient the upper end 67 into a radially contracted configuration, and can be deformed radially outward to orient the upper end 67 into a radially expanded configuration. In a preferred embodiment, segments 92 are configured to be sufficiently resilient such that an externally applied radially inward force applied to segments 92 moves upper end 67 to the radially contracted configuration, and when the externally applied radially inward force is removed, the configuration of segments 92 generates a radially outward force sufficient to move upper end 67 from the radially contracted configuration to the radially expanded configuration. In an alternative embodiment, segments 92 are configured to be sufficiently resilient such that an externally applied radially outward force moves upper end 67 to the radially expanded configuration, and when the externally applied radially inward force is removed, the configuration of segments 92 generates a radially inward force sufficient to move upper end 67 from the radially contracted configuration to the radially expanded configuration. In another alternative embodiment, segments 92 are configured such that an externally applied radially inward force is required to move upper end 67 to the radially contracted configuration, and no externally applied radially outward force is required to move upper end 67 to the radially expanded configuration.

[0071] Figure 5 c shows that the bottom of the second sleeve 66 is provided with a plurality of radial protrusions 112 spaced circumferentially therefrom. The radial protrusions 112 are configured to be received in the grooves 76 of the first sleeve 64 to maintain the sleeves 64, 66 aligned relative to each other. The protrusions 112 are provided at the lower base end 102 of the segment 92, i.e., on the bottom of the tines 104. The protrusions 112 extend radially outward from the outer circumferential surface 104a of the tines 104. During installation of the sleeve assembly 62 on the nozzle 26 ( Figure 2-3 b) the protrusion 112 limits rotational movement of the second sleeve 66 relative to the first sleeve 64. More specifically, the axially extending, circumferentially facing edges 112a, 112b of the protrusion 112 are configured to circumferentially contact the axially extending, circumferentially facing longitudinal edges 88b, 88c, thereby limiting rotational movement 26 of the second sleeve 66 relative to the first sleeve 64 during installation of the sleeve assembly 62 on the nozzle.

[0072] exist Figure 3-5 In the embodiment shown in Figure c, the sleeves 64 and 66 are configured so that each protrusion 84 of the first sleeve 64 is configured to be directly inserted into one of the grooves 94 of the second sleeve 66 between the two protrusions 106 of the second sleeve 66, and each protrusion 106 of the second sleeve 66 is configured to be directly inserted into one of the grooves 76 of the first sleeve 64 between the two protrusions 84 of the first sleeve 64. Specifically, when the sleeve 66 is in the radially expanded configuration, each protrusion 84 of the first sleeve 64 has a circumferential width that is substantially the same as that of each groove 94 at the height of the protrusion 106; when the sleeve 64 is in the radially expanded configuration, each protrusion 106 of the second sleeve 66 has a circumferential width that is substantially the same as that of each groove 76 at the height of the protrusion 84. Figure 3As shown, when sleeves 64, 66 are in their installed positions in nozzle 26, each protrusion 84 of first sleeve 64 is directly received in one of slots 94 of second sleeve 66 between two protrusions 106 of second sleeve 66, and each protrusion 106 of second sleeve 66 is directly received in one of slots 76 of first sleeve 64 between two protrusions 84 of first sleeve 64. In these installed positions, each protrusion 84 circumferentially contacts two adjacent protrusions 106, and each protrusion 106 circumferentially contacts two adjacent protrusions 84. More specifically, in the installed positions of sleeves 64, 66, each circumferentially facing side edge 84f contacts one circumferentially facing side 106f, and each circumferentially facing side edge 84g contacts one circumferentially facing side 106g. Segments 74 are wedged between segments 92 in an intermeshing manner to rotationally secure sleeves 64, 66 together. Specifically, the projections 106 are wedged between the projections 84 in an intermeshing manner so that the sleeves 64, 66 are rotationally fixed together. In the installed position of the sleeves, the wings 108, 109 engage in the stepped portions 84h to help lock the sleeves 64, 66 together.

[0073] Now refer to Figure 1-8 A method for replacing the sleeve 26 with the sleeve assembly 62 according to an embodiment of the present invention is described. First, the RVCH 14 is removed from the housing 16 and placed on the headstock for sleeve replacement to facilitate access to the lower end 32. Next, the sleeve 26 is removed from the nozzle 24. In a preferred embodiment, the radially enlarged portion 48 of the sleeve 26 is separated so that the sleeve 26 can be pulled downwardly out of the lower end 32 from under the RVCH 14 while on the headstock. The sleeve assembly 62 is configured to be inserted into the nozzle 24 from the lower end 32 while on the headstock.

[0074] The method includes providing the sleeve assembly 62 to the interior of the RVCH 14. Before providing the funnel 72 to the interior of the RVCH 14, the funnel 72 can be installed on the lower end 90 of the first sleeve 64. The second sleeve 66 is installed inside the first sleeve 64 through the upper end 65 of the first sleeve 64, and the second sleeve 66 is coaxial with the first sleeve 64 before the sleeves 64, 66 are inserted into the nozzle 24. The second sleeve 66 is first inserted through the upper end 65 of the first sleeve 64 into the lower end 100, wherein the segments 74 are radially aligned with the grooves 94 and the segments 92 are radially aligned with the grooves 76 by sliding the protrusions 112 into the grooves 76. The second sleeve 66 is axially slid into the first sleeve 64 so that the protrusions 84 are positioned axially offset from the protrusions 106, and in particular, vertically above the protrusions 106.

[0075] Then, the sleeve assembly 62 is installed in the nozzle 24 so that the radially variable end 65 of the first sleeve 64 and the radially variable end 67 of the second sleeve 66 are received by the support portion 44. The radially variable ends 65, 67 are in a radially contracted configuration during installation, and are in a radially expanded configuration after the sleeve assembly 62 is installed in the nozzle 24.

[0076] The installation first includes inserting the upper end 60 of the sleeve assembly 62 into the lower end 32 of the nozzle 24 with the protrusions 84 positioned axially offset from the protrusions 106 and the upper ends 65, 67 both in the radially contracted configuration. A radially inward force can be applied to the segments 74 to orient the upper end 65 of the first sleeve 64 in the radially contracted configuration, and a radially inward force can be applied to the segments 92 to orient the upper end 67 of the second sleeve 66 in the radially contracted configuration such that the outermost diameter of the upper end 65 of the first sleeve 64, as defined by the maximum distance between the outer circumferential surfaces 84a of the protrusions 84, is less than the inner diameter of the nozzle 24 at the lower end 32, and the outermost diameter of the upper end 67 of the second sleeve 66, as defined by the maximum distance between the outer circumferential surfaces 106a of the protrusions 106, is less than the inner diameter of the nozzle 24 at the lower end 32. For example, as Figure 6 As shown in a, after the second sleeve 66 is installed inside the first sleeve 64, the compression tool 120 (in Figure 6 The compression tool 120 (a, a ring) can be installed on the outer circumferential surface 84a of the protrusion 84 of the stepped portion 84h. The installation of the compression tool 120 forces the segments 74 to elastically deform radially inward, which causes the segments 74 to contact the segments 92 at the tines 104 and also forces the segments 92 to elastically deform radially inward. After the compression tool 120 is installed, the segments 74, 92 are retained by the compression tool 120 such that the variable end 65 of the first sleeve 64 is retained in a radially contracted configuration by the compression tool 120, and the variable end 67 of the first sleeve 66 is retained in a radially contracted configuration by the compression tool 120. Then, with the upper ends 65, 76 of the sleeves 64, 66 in their radially contracted configuration, the sleeve assembly 62 is forced upward through the second end 32 of the nozzle 24. After the upper ends 65 , 67 of the sleeves 64 , 66 are inserted into the second end 32 of the nozzle 24 , the compression tool 120 may be removed from the ends 65 , 67 of the sleeves 64 , 66 by sliding the compression tool 120 downward.

[0077] Figure 7Another embodiment of a compression tool 140 is shown that can be used to elastically deform the segments 74, 92 radially inward. The compression tool 140 is in the form of a quick-connect clamp that includes two clamping portions 142, 143 held together by two fasteners 144, 145. Specifically, each clamping portion 142, 143 includes a respective semicircular contact portion 146, 147 having an inner circumferential surface 142a, 143a for contacting the outer circumferential surface 84a of the protrusion 84 in the stepped portion 84h, and two fastening portions 148a, 148b, 149a, 149b that extend radially outward from the respective contact portions 146, 147 at opposite circumferential ends of the respective contact portions 146, 147. Each fastening portion 148a, 148b, 149a, 149b includes a respective aperture 150b, 151a, 151b (view of aperture 148a is obscured) extending axially therethrough to receive a respective fastener 144, 145.

[0078] exist Figure 7 In the illustrated view, the aperture of the fastening portion 148a of the clamp 142 is aligned with the aperture 151b of the fastening portion 149b of the clamp 143, and the fastener 145 is passed through both the aperture of the fastening portion 148a and the aperture 151b. The fastener 144 is received in the aperture 150b but not in the aperture 151a, so that the clamps 142, 143 can be rotated together about the fastener 145 to clamp the clamps 142, 143 onto the ends 65, 67 of the sleeves 64, 66 and compress the segments 74, 92 radially inward. Once the clamps 142, 143 with the elastically deformed ends 65, 67 of the sleeves 64, 66 are brought into the radially contracted configuration, the fastener 144 is introduced into the aperture 151a to retain the ends 65, 67 of the sleeves 64, 66 in the radially contracted configuration. After the upper ends 65 , 67 of the sleeves 64 , 66 are inserted into the second end 32 of the nozzle 24 , the fastener 144 can be pulled out of the hole 151 a and the compression tool 140 can be removed from the sleeves 64 , 66 .

[0079] More specifically, if Figure 6 As shown schematically in FIG. b, after the compression tool 120 or 140 is removed, during installation of the sleeve assembly 62 into the nozzle 24, as the sleeves 64, 66 move upward through the nozzle 24, the variable ends 65, 67 of the sleeves 64, 66, respectively, are held in a radially contracted configuration by contact between the inner circumferential surface 36b of the nozzle 24 and the outer circumferential surface 84a of the protrusion 84. Figure 6As shown in FIG. 2 , during installation, an expansion tool 122 can be housed within the sleeves 64, 66. The expansion tool 122 includes a rod 124 and a head 126 at the end of the rod 124, wherein the outer diameter of the rod 124 is smaller than the innermost diameter of the segments in the radially contracted configuration. The outer diameter of the head 126 is larger than the innermost diameter of the segments in the radially contracted configuration. When the sleeves 64, 66 are slid upward through the nozzle 24, the rod 124 is within the sleeves 64, 66, and the head 126 is positioned above the sleeve 64 and above most of the sleeve 66. Figure 6 As shown in FIG. 2 b , the bottom edge 126 a of the head portion 126 may be positioned below the upper surface 106 e and the facing surface 106 d of the protrusion 106 . Figure 6 d shows the upper ends 65 , 67 of the sleeves 64 , 66 after reaching the radially enlarged support portion 44 at the upper end 28 of the nozzle 24 and before the upper ends 65 , 67 are radially expanded.

[0080] After the upper ends 65 and 67 of the sleeves 64 and 66 reach the radially expanded support portion 44, the upper end 65 of the sleeve 64 radially expands to a radially expanded orientation, and the second sleeve 66 elastically deforms from the mounting configuration to the retaining configuration to keep the end 65 of the first sleeve 64 in the radially expanded configuration, so that the sleeves 64 and 66.

[0081] The installation of the variant to the first configuration involves, once the upper ends 65, 67 of the sleeves 64, 66 are above the support surface 44a of the nozzle 24, moving the two sleeves 64, 66 to Figure 6 c The orientation shown in FIG. 3 is that the upper end 65 of the sleeve 64 is radially expanded into a radially expanded orientation such that the outer circumferential surface 84a of the protrusion 84 is positioned radially farther from the center axis CA than the inner circumferential surface 42a; and the upper end 67 of the sleeve 68 is radially expanded into a radially expanded orientation such that the outer circumferential surface 106a of the protrusion 106 is positioned radially farther from the center axis CA than the inner circumferential surface 42a.

[0082] This can be performed by pulling the expansion tool 122 downward so that the bottom edge 126a contacts the surface 106d of the segment 92 and the upper end 67 of the sleeve 66, and in particular the segment 92, is forced radially outward. As the upper end 67 of the sleeve 66 is forced radially outward, the outer circumferential surface of the segment 92 contacts the inner circumferential surface of the segment 74 and the upper end 65 of the sleeve 64, in particular the protrusion 84, is forced radially outward. The upper end 67 of the sleeve 66, in the radially expanded orientation, is then pulled downward so that the protrusion 106 is drawn into the groove 76 and axially aligned with the protrusion 84, and the protrusion 84 enters the groove 94, causing the segment 74 to engage with the segment 92.

[0083] During the radial expansion of the upper ends 65, 67 of the sleeves 64, 66 and the axial alignment of the protrusion 106 with the protrusion 84 in the groove 76, the wings 108, 109 align in the step 84h in the outer circumferential surface 84a of the protrusion 84. The alignment of the wings 108, 109 in the step 84h helps to lock the sleeves 64, 66 in place relative to each other. Figure 6 As shown in FIG. 5 , in this installed orientation, with the segments 74 and 92 engaged with each other, the cylindrical base 96 of the second sleeve 66 is disposed within and coaxial with the top portion 70 a of the cylindrical base 70 of the first sleeve 64 , as shown in FIG. Figure 8 shown.

[0084] After the upper ends 65, 67 of the sleeves 64, 66 are radially expanded and the protrusion 106 is axially aligned with the protrusion 84 in the slot 76, the lower surface 84c of the protrusion 84 and the lower surface 106c of the protrusion 106 contact the support surface 44a to axially retain the first sleeve 64 in position in the nozzle 24. The lower surface 84c of the protrusion 84 and the lower surface 106c of the protrusion 106 axially abut the support surface 44a so that the sleeves 64, 66 cannot be pulled downward when the upper ends 65, 67 of the sleeves 64, 66 are in the radially expanded configuration. Once the upper ends 65, 67 are radially expanded so that the protrusion 84 is in the groove 94 and the protrusion 106 is in the groove 76, and the segments 74 and 92 are engaged with each other, the protrusions 84, 106 cannot be radially contracted radially inwardly into a radially contracted configuration by contact between the edges 84f, 84g and the edges 106f, 106g, and the upper end 60 of the sleeve assembly 62 is locked in the upper end 28 of the nozzle 24. The sleeves 64, 66 can then be further connected together, for example, by welding. Specifically, as shown in FIG. Figure 8 As shown, the sleeves 64, 66 can be connected together using a welding tool 150. The welding tool 150 is configured to be received inside the sleeves 64, 66 and includes a welding head 152 configured to heat the sleeves 64, 66 to weld the sleeves 64, 66 together. In a preferred embodiment, as shown in FIG. Figure 8 As shown, the sleeve 64 includes an annular shoulder 160 at its inner circumference, which is configured to axially abut the bottom edge 100a of the lower end 100 of the second sleeve 66, and the welding tool 150 can weld the sleeves 64, 66 together by heating the bottom edge 100a and the annular shoulder 160 via the welding head 152 to join the bottom edge 100a and the annular shoulder 160 to each other.

[0085] In the foregoing description, the present invention has been described with reference to specific exemplary embodiments and examples thereof. However, it will be apparent that various modifications and changes may be made thereto without departing from the broader spirit and scope of the present invention as set forth in the appended claims. Accordingly, the description and drawings are to be regarded as illustrative rather than restrictive.

Claims

1. A method for replacing a damaged sleeve lining a tube passing through a nuclear reactor pressure vessel, the damaged sleeve having an end including a radially enlarged end portion, the end portion being configured to rest on a support portion of the tube to retain the damaged sleeve in the tube, the method comprising: removing the damaged sleeve from the tube; A new sleeve assembly is provided that includes a first sleeve having a radially variable end configured to deform between a radially contracted configuration and a radially expanded configuration, and a retainer configured to deform between a mounted configuration and a retained configuration; installing the sleeve assembly in the pipe such that a radially variable end of the first sleeve is received by the support portion, the radially variable end being in a radially contracted configuration during installation and in a radially expanded configuration after the sleeve assembly is installed in the pipe; and The retainer is deformed from the mounting configuration to the retaining configuration to retain the radially variable end of the first sleeve in the radially expanded configuration.

2. The method of claim 1 , wherein installing the sleeve assembly comprises inserting the radially variable end of the first sleeve in a radially contracted configuration into the first end of the tube, the radially variable end of the first sleeve being in a radially expanded configuration at the second end of the tube after installation. 3 . The method of claim 2 , wherein the first end of the tube is a lower end of the tube and the second end of the tube is an upper end of the tube.

4. The method of claim 1, wherein during installation of the sleeve assembly in the pipe, the retainer is a second sleeve retained in the radially variable end of the first sleeve.

5. The method of claim 4 , wherein the second sleeve includes a radially variable end configured to deform between a radially contracted configuration and a radially expanded configuration, wherein in the installed configuration the radially variable end of the second sleeve is in a radially contracted configuration and in the retaining configuration it is in a radially expanded configuration.

6. The method of claim 5 , wherein the radially variable end of the first sleeve includes a plurality of first segments circumferentially separated from each other by first grooves, and the radially variable end of the second sleeve includes a plurality of second segments circumferentially separated from each other by second grooves, the first segments and the second segments being flexible radially inward and radially outward.

7. The method of claim 6, wherein deforming the retainer from the mounting configuration to the retaining configuration to retain the radially variable end of the first sleeve in the radially expanded configuration comprises engaging the first segment and the second segment with each other.

8. The method of claim 7 , wherein after the sleeve assembly is installed in the tube, each of the circumferentially spaced first segments includes a first radially outwardly extending protrusion that rests on the support portion, and after the sleeve assembly is installed in the tube, each of the circumferentially spaced second segments includes a second radially outwardly extending protrusion that rests on the support portion.

9. The method of claim 8, wherein the first protrusions are circumferentially separated from each other by the first grooves and the second protrusions are circumferentially separated from each other by the second grooves, and engaging the first segment and the second segment with each other includes aligning the first segment and the second segment so that each of the first protrusions is received in one of the second grooves and each of the second protrusions is received in one of the first grooves.

10. The method of claim 9, wherein deforming the retainer from the mounting configuration to the retaining configuration to retain the radially variable end of the first sleeve in the radially expanded configuration comprises deforming the second segment to force the second protrusions radially outward from each other and pulling the second sleeve downward so that each of the second protrusions is located in one of the first slots and the first protrusions and the second protrusions are axially aligned with each other.

11. The method of claim 6, wherein each of the second segments is provided with a protrusion extending radially outwardly therefrom, each of the protrusions being received in one of the first grooves during installation of the sleeve assembly in the tube and deformation of the retainer from the installation configuration to the retaining configuration.

12. The method of claim 1, wherein the first sleeve includes a funnel at an end thereof opposite the radially variable end, the funnel being a portion of the first sleeve during installation of the sleeve assembly in the pipe.

13. The method of claim 1 , wherein the tube is a control rod drive mechanism nozzle passing through a closure head of the nuclear reactor pressure vessel, the closure head being separated from the cylindrical shell of the nuclear reactor pressure vessel during installation of the sleeve assembly in the tube.

14. A control rod drive mechanism thermal sleeve for insertion into a control rod drive mechanism nozzle of a nuclear reactor pressure vessel, the control rod drive mechanism thermal sleeve comprising a first sleeve and a retainer; The first sleeve comprises: a radially variable end configured to deform between a radially contracted configuration and a radially expanded configuration, in which the radially variable end is configured to retain the first sleeve in the control rod drive mechanism nozzle; and another end opposite the radially variable end, the other end comprising a funnel having a frustoconical portion with a maximum diameter edge defining an end edge of the other end; and The retainer is configured to deform between a mounting configuration and a retaining configuration in which the retainer is configured to retain the first sleeve in a radially expanded configuration.

15. The CRDM thermal sleeve of claim 14, wherein in the installed configuration and the retained configuration the retainer is a second sleeve retained in the radially variable end of the first sleeve.

16. The control rod drive mechanism thermal sleeve of claim 15 , wherein the second sleeve includes a radially variable end configured to deform between a radially contracted configuration and a radially expanded configuration, wherein the radially variable end of the second sleeve is in the radially contracted configuration in the installed configuration and in the radially expanded configuration in the retained configuration.

17. The control rod drive mechanism thermal sleeve according to claim 16, wherein the radially variable end of the first sleeve includes a plurality of first segments circumferentially separated from each other by first grooves, and the radially variable end of the second sleeve includes a plurality of second segments circumferentially separated from each other by second grooves, the first segments and the second segments being flexible radially inwardly and radially outwardly.

18. The CRDM thermal sleeve of claim 17, wherein the first segment and the second segment are configured to engage each other in the retained configuration of the second sleeve.

19. The CRDM thermal sleeve of claim 18 , wherein each circumferentially spaced first segment includes a first protrusion extending radially outward, and each circumferentially spaced second segment includes a second protrusion extending radially outward, the first segments and the second segments being engaged with each other by each first protrusion being received in one of the second grooves and each second protrusion being received in one of the first grooves.

20. The CRDM thermal sleeve of claim 17, wherein each of said second segments is provided with a protrusion extending radially outwardly therefrom, each of said protrusions being configured to be received in one of said first grooves in both the installed and retained configurations.

Images