Methods and apparatuses for operating and repairing nuclear reactors

Method of repairing nuclear reactors that include one or more submerged lines welded to one or more support brackets may include: removing a damaged section of one of the one or more submerged lines; and replacing the damaged section of the one of the one or more submerged lines without welding. Methods of operating nuclear reactors that include one or more submerged lines welded to one or more support brackets may include: shutting down the nuclear reactor; repairing damage to at least one of the one or more submerged lines without welding; and starting up the nuclear reactor. Methods of operating nuclear reactors that include one or more submerged lines welded to one or more support brackets may include: cooling down the nuclear reactor; repairing damage to at least one of the one or more submerged lines without welding; and heating up the nuclear reactor.

BACKGROUND

Example embodiments relate to methods and apparatuses for operating and repairing nuclear reactors. Additionally, example embodiments relate to methods and apparatuses for operating and repairing nuclear reactors that include one or more submerged lines welded to one or more support brackets.

2. Description of Related Art

FIG. 1is a sectional view, with parts cut away, of reactor pressure vessel (“RPV”)100in a related art BWR. During operation of the BWR, coolant water circulating inside RPV100is heated by nuclear fission produced in core102. Feedwater is admitted into RPV100via feedwater inlet104and feedwater sparger106(a ring-shaped pipe that includes apertures for circumferentially distributing the feedwater inside RPV100). The feedwater from feedwater sparger106flows down through downcomer annulus108(an annular region between RPV100and core shroud110).

Core shroud110is a stainless steel cylinder that surrounds core102. Core102includes a multiplicity of fuel bundle assemblies112(two 2×2 arrays, for example, are shown inFIG. 1). Each array of fuel bundle assemblies112is supported at or near its top by top guide114and at or near its bottom by core plate116. Top guide114provides lateral support for the top of fuel bundle assemblies112and maintains correct fuel-channel spacing to permit control rod insertion.

The coolant water flows downward through downcomer annulus108and into core lower plenum118. The coolant water in core lower plenum118in turn flows up through core102. The coolant water enters fuel assemblies112, wherein a boiling boundary layer is established. A mixture of water and steam exits core102and enters core upper plenum120under shroud head122. Core upper plenum120provides standoff between the steam-water mixture exiting core102and entering standpipes124. Standpipes124are disposed atop shroud head122and in fluid communication with core upper plenum120.

The steam-water mixture flows through standpipes124and enters steam separators126(which may be, for example, of the axial-flow, centrifugal type). Steam separators126substantially separate the steam-water mixture into liquid water and steam. The separated liquid water mixes with feedwater in mixing plenum128. This mixture then returns to core102via downcomer annulus108. The separated steam passes through steam dryers130and enters steam dome132. The dried steam is withdrawn from RPV100via steam outlet134for use in turbines and other equipment (not shown).

The BWR also includes a coolant recirculation system that provides the forced convection flow through core102necessary to attain the required power density. A portion of the water is sucked from the lower end of downcomer annulus108via recirculation water outlet136and forced by a centrifugal recirculation pump (not shown) into a plurality of jet pump assemblies138(only one of which is shown) via recirculation water inlets140. Jet pump assemblies138are circumferentially distributed around core shroud110and provide the required reactor core flow.

As shown inFIG. 1, a related art jet pump assembly138includes a pair of inlet mixers142. A typical BWR includes 16 to 24 inlet mixers142. Each inlet mixer142has an elbow144welded to it that receives water from a recirculation pump (not shown) via inlet riser146. An example inlet mixer142includes a set of five nozzles circumferentially distributed at equal angles about the axis of inlet mixer142. Each nozzle is tapered radially inwardly at its outlet. Jet pump assembly138is energized by these convergent nozzles. Five secondary inlet openings are radially outside of the nozzle exits. Therefore, as jets of water exit the nozzles, water from downcomer annulus108is drawn into inlet mixer142via the secondary inlet openings, where it is mixed with coolant water from the recirculation pump. The coolant water then flows into jet pump assembly138.

FIG. 2is a sectional view, with parts cut away and/or in silhouette, of the interior of RPV100in a related art BWR. Each jet pump assembly138has a sensing line200that is in fluid communication with a plurality of pressure taps at the top of diffuser148and with instrumentation (not shown) located outside RPV100. Sensing lines200allow the core flow to be measured and monitored. The flow through and outside jet pump assemblies138includes pressure fluctuations from various sources in the nuclear reactor. These pressure fluctuations may have frequencies close to one or more natural vibration modes of sensing lines200. These vibration modes depend on the spacing and stiffness of sensing lines200and support brackets202that attach sensing lines200to one or more of jet pump assemblies138. When an excitation frequency happens to be too close to matching the natural frequency of one or more sensing lines200at some particular location, vibration of sensing lines200may exert loads on sensing lines200and/or support brackets202that can cause cyclic fatigue cracking and/or failure of sensing lines200and/or support brackets202. This phenomenon may result in loss of the indication of core flow which, if it occurs at enough locations, may require plant shutdown.

Sensing lines200also may be subjected to damage caused by objects (i.e., head bolts for core shroud110) falling on sensing lines200during maintenance, repair, and/or other procedures. This may be particularly true for sensing lines200oriented in a substantially horizontal direction, such as sensing lines200routed from jet pump assemblies138to penetration nozzle204through wall206of RPV100.

Various solutions to the problems of jet pump sensing line failure, repair, and replacement have been proposed, as discussed, for example, in U.S. Pat. Nos. 5,615,239 (“the '239 patent”), 5,752,807 (“the '807 patent”), 6,163,588 (“the '588 patent”), 6,233,301 B1 (“the '301 patent”), and 6,435,839 B1 (“the '839 patent”). The disclosures of the '239 patent, the '807 patent, the '588 patent, the '301 patent, and the '839 patent are incorporated in this application by reference. However, these various solutions do not include methods or apparatuses for operating and repairing nuclear reactors that include one or more submerged lines welded to one or more support brackets, wherein damage to one or more of the submerged lines can be repaired without welding.

SUMMARY

Example embodiments may relate to methods and apparatuses for operating and repairing nuclear reactors. Additionally, example embodiments may relate to methods and apparatuses for operating and repairing nuclear reactors that include one or more submerged lines welded to one or more support brackets, wherein damage to one or more of the submerged lines can be repaired without welding.

In an example embodiment, methods of repairing nuclear reactors that include one or more submerged lines welded to one or more support brackets may include: removing a damaged section of one of the one or more submerged lines; and replacing the damaged section of the one of the one or more submerged lines without welding.

In another example embodiment, methods of repairing nuclear reactors that include one or more submerged lines welded to one or more support brackets may include: removing one or more damaged sections of the one or more submerged lines; and replacing the one or more damaged sections of the one or more submerged lines without welding.

In yet another example embodiment, methods of operating nuclear reactors that include one or more submerged lines welded to one or more support brackets may include: shutting down the nuclear reactor; repairing damage to at least one of the one or more submerged lines without welding; and starting up the nuclear reactor.

In still another example embodiment, methods of operating nuclear reactors that include one or more submerged lines welded to one or more support brackets may include: cooling down the nuclear reactor; repairing damage to at least one of the one or more submerged lines without welding; and heating up the nuclear reactor.

In a further example embodiment, apparatuses for repairing nuclear reactors that include one or more submerged lines welded to one or more support brackets may include: a body including one or more sites for fixing a spool piece to the body without welding.

In another further example embodiment, apparatuses for repairing nuclear reactors that include one or more submerged lines welded to one or more support brackets may include: a spool piece; and a body including one or more sites for fixing the spool piece to the body without welding.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

Example embodiments will now be described more fully with reference to the accompanying drawings. Embodiments, however, may be embodied in many different forms and should not be construed as being limited to the example embodiments set forth herein. Rather, these example embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope to those skilled in the art.

It will be understood that when a component is referred to as being “on,” “connected to,” “coupled to,” or “fixed to” another component, it may be directly on, connected to, coupled to, or fixed to the other component or intervening components may be present. In contrast, when a component is referred to as being “directly on,” “directly connected to,” “directly coupled to,” or “directly fixed to” another component, there are no intervening components present. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper,” and the like may be used herein for ease of description to describe one component and/or feature relative to another component and/or feature, or other component(s) and/or feature(s), as illustrated in the drawings. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures.

Reference will now be made to example embodiments, which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like components throughout.

In an example embodiment, methods of repairing nuclear reactors that include one or more submerged lines welded to one or more support brackets may include: removing a damaged section of one of the one or more submerged lines; and/or replacing the damaged section of the one of the one or more submerged lines without welding

The submerged lines may be, for example, instrumentation lines (i.e., jet pump differential pressure sensing lines) and/or one or more other submerged lines.

The damaged section may be identified, for example, by visual or other inspection method(s) known to one of ordinary skill in the art. The visual inspection may be conducted, for example, using a video device. At some point before or during the removal of the damaged section, the damaged section should be secured (i.e., tethered) so as to prevent it from being misplaced or lost in the nuclear reactor when it has been cut out.

Removing the damaged section may include: cutting out the damaged section from the one of the one or more submerged lines; and/or cutting out the damaged section from one of the one or more support brackets. The cuts on the submerged lines may be, for example, smooth and/or substantially perpendicular to the axial direction of the submerged line.

The damaged section may be cut out, for example, by electrical discharge machining (“EDM”) or other suitable technique(s) known to one of ordinary skill in the art. After the damaged section has been cut out, it may be removed from the nuclear reactor.

Replacing the damaged section may include: substituting a spool piece, comprising ends, in place of the damaged section; joining the ends of the spool piece to the one of the one or more submerged lines; and/or connecting the spool piece to one of the one or more support brackets.

FIG. 3is a diagram illustrating spool piece300and ends302,304of a submerged line from which the damaged section has been cut out, according to an example embodiment.FIG. 4is a diagram illustrating spool piece300, ends302,304of a submerged line from which the damaged section has been cut out, and shrink fittings400,402, according to another example embodiment.

Spool piece300may include, for example, a length of tubing comparable to the damaged section cut out from a submerged line (and from a support bracket). Ends306,308of spool piece300should correspond to ends302,304of the submerged line from which the damaged section is to be cut out or was cut out.

Spool piece300may be longer than, about the same length as, or shorter than the damaged section that is to be cut out or was cut out. The outer diameter of spool piece300may be larger than, about the same as, or smaller than the outer diameter of the damaged section that is to be cut out or was cut out. The inner diameter of spool piece300may be larger than, about the same as, or smaller than the inner diameter of the damaged section that is to be cut out or was cut out. The inner diameter of spool piece300may be larger than, about the same as, or smaller than the outer diameter of the damaged section that is to be cut out or was cut out.

Spool piece300may include one or more grooves, ridges, lips, etc. on its inner surface near one or both ends306,308. When joining ends306,308of spool piece300to the submerged line from which the damaged section was cut out, if spool piece300is fitted over corresponding ends302,304of the submerged line, the one or more grooves, ridges, lips, etc. may improve contact between ends306,308of spool piece300and ends302,304of the submerged line.

The one or more grooves may include, for example, one or more spiral grooves, one or more parallel grooves, and/or one or more circumferential grooves. The one or more grooves may or may not be continuous. The one or more ridges may include, for example, one or more spiral ridges, one or more parallel ridges, and/or one or more circumferential ridges. The one or more ridges may or may not be continuous. The one or more lips may or may not be continuous.

Spool piece300may include, for example, one or more materials used in construction of a nuclear reactor. Spool piece300may include, for example, one or more high-strength alloys used in construction of a nuclear reactor. Spool piece300may include, for example, one or more stainless steels (i.e., Type 304, Type 316, and/or Type XM19) and/or one or more nickel-chromium-iron alloys (i.e., Inconel™ X750).

In addition or in the alternative, spool piece300may include, for example, one or more materials that change dimension(s) when exposed to temperature changes and/or that have shape-memory characteristics. Spool piece300may include, for example, one or more metals or metal alloys that change dimension(s) when exposed to temperature changes and/or that have shape-memory characteristics. In an example embodiment, spool piece300may include one or more alloys of approximately 50% titanium and approximately 50% nickel, known, for example, by the trade names Nitinol and/or Tinel, and available, for example, from Memry Corporation of Bethel, Conn., and Menlo Park, Calif. The one or more alloys may include, for example, more nickel than titanium (i.e., approximately 55 wt % Ni and approximately 45 wt % Ti). In addition or in the alternative, the one or more alloys may include, for example, one or more other alloying materials, such as niobium. In this case, the one or more alloys may include, for example, approximately 56 wt % Ni, approximately 14 wt % Nb, and approximately 30 wt % Ti). In addition to other characteristics, these alloys tend to contract with increasing temperature due to one or more phase changes occurring in the alloys.

An object that includes one or more materials that change dimension(s) when exposed to temperature changes and/or that have shape-memory characteristics may be processed over a mandrel or other suitable device to expand the object. Typically, the processing is done at temperature(s) lower than a phase-change temperature. If the object is generally round, the mandrel may also be generally round.

As discussed above, when joining ends306,308of spool piece300to the submerged line from which the damaged section was cut out, spool piece300may be fitted over corresponding ends302,304of the submerged line. In this case, spool piece300may include, for example, one or more materials used in construction of a nuclear reactor and/or one or more materials that change dimension(s) when exposed to temperature changes and/or that have shape-memory characteristics. In addition or in the alternative, one or more shrink fittings400,402may be disposed on spool piece300. One or more shrink fittings400,402may act on spool piece300to fix or help fix spool piece300to corresponding ends302,304of the submerged line.

One or more shrink fittings400,402may include, for example, one or more materials that change dimension(s) when exposed to temperature changes and/or that have shape-memory characteristics. One or more shrink fittings400,402may include, for example, one or more metals or metal alloys that change dimension(s) when exposed to temperature changes and/or that have shape-memory characteristics. In an example embodiment, one or more shrink fittings400,402may include one or more alloys of approximately 50% titanium and approximately 50% nickel, known as Nitinol and/or Tinel, as discussed above. In addition or in the alternative, the one or more alloys may include, for example, one or more other alloying materials, such as niobium, as also discussed above.

One or more shrink fittings402,402may include many geometries. For example, one or more shrink fittings400,402may be generally round (i.e., circular, oval-shaped, rounded, curved). In an example embodiment, one or more shrink fittings400,402are shrink rings available, for example, from Memry Corporation.

Spool piece300may include one or more grooves, ridges, lips, etc. on its outer surface near one or both ends306,308. Similarly, one or more shrink fittings400,402may include one or more grooves, ridges, lips, etc. on their inner surface. When one or more shrink fittings400,402act on spool piece300to fix or help fix spool piece300to corresponding ends302,304of the submerged line, the one or more grooves, ridges, lips, etc. on the outer surface of spool piece300and/or the one or more grooves, ridges, lips, etc. on the inner surface of one or more shrink fittings400,402may improve contact between spool piece300and one or more shrink fittings400,402, and/or improve contact between ends306,308of spool piece300and ends302,304of the submerged line.

The one or more grooves may include, for example, one or more spiral grooves, one or more parallel grooves, and/or one or more circumferential grooves. The one or more grooves may or may not be continuous. The one or more ridges may include, for example, one or more spiral ridges, one or more parallel ridges, and/or one or more circumferential ridges. The one or more ridges may or may not be continuous. The one or more lips may or may not be continuous.

One or more shrink fittings400,402may be disposed on spool piece300in the position(s) shown inFIG. 4prior to spool piece300being fitted over corresponding ends302,304of the submerged line. In addition or in the alternative, one or more shrink fittings400,402may be disposed elsewhere on spool piece300(or on end302and/or end304of the submerged line), and then disposed in the position(s) shown inFIG. 4after spool piece300is fitted over corresponding ends302,304of the submerged line.

FIG. 5is a diagram illustrating spool piece500, couplings502,504(sleeves510,512only), and ends302,304of a submerged line from which the damaged section has been cut out, according to an example embodiment.FIG. 6is a diagram illustrating spool piece500, couplings502,504(sleeves510,512and shrink fittings600,602,604,606), and ends302,304of a submerged line from which the damaged section has been cut out, according to another example embodiment.

Spool piece500may include, for example, a length of tubing comparable to the damaged section cut out from a submerged line (and from a support bracket). Ends506,508of spool piece500should correspond to ends302,304of the submerged line from which the damaged section is to be cut out or was cut out.

Spool piece500may be longer than, about the same length as, or shorter than the damaged section that is to be cut out or was cut out. The outer diameter of spool piece500may be larger than, about the same as, or smaller than the outer diameter of the damaged section that is to be cut out or was cut out. The inner diameter of spool piece500may be larger than, about the same as, or smaller than the inner diameter of the damaged section that is to be cut out or was cut out.

When joining ends506,508of spool piece500to the submerged line from which the damaged section was cut out, spool piece500may be disposed adjacent to corresponding ends302,304of the submerged line, instead of being fitted over them. In this case, spool piece500may include, for example, one or more materials used in construction of a nuclear reactor. Spool piece500may include, for example, one or more high-strength alloys used in construction of a nuclear reactor. Spool piece500may include, for example, one or more stainless steels (i.e., Type 304, Type 316, and/or Type XM19) and/or one or more nickel-chromium-iron alloys (i.e., Inconel™ X750).

One or more couplings502,504may be disposed on spool piece500. Each coupling502,504may include sleeve510,512or sleeve510,512and one or more shrink fittings600,602,604,606. If one or more couplings502,504include only sleeve510,512, then sleeve510,512may include, for example, one or more materials that change dimension(s) when exposed to temperature changes and/or that have shape-memory characteristics. In an example embodiment, sleeve510,512may include one or more alloys of approximately 50% titanium and approximately 50% nickel, known as Nitinol and/or Tinel, as discussed above. In addition or in the alternative, the one or more alloys may include, for example, one or more other alloying materials, such as niobium, as also discussed above.

If one or more couplings502,504includes sleeve510,512and one or more shrink fittings600,602,604,606, then sleeve510,512may include, for example, one or more materials used in construction of a nuclear reactor and/or one or more materials that change-dimension(s) when exposed to temperature changes and/or that have shape-memory characteristics. In an example embodiment, sleeve510,512may include, for example, one or more stainless steels (i.e., Type 304, Type 316, and/or Type XM19) and/or one or more nickel-chromium-iron alloys (i.e., Inconel™ X750). In addition or in the alternative, sleeve510,512may include one or more alloys of approximately 50% titanium and approximately 50% nickel, known as Nitinol and/or Tinel, as discussed above. In addition or in the alternative, the one or more alloys may include, for example, one or more other alloying materials, such as niobium, as also discussed above.

One or more shrink fittings600,602,604,606may include, for example, one or more materials that change dimension(s) when exposed to temperature changes and/or that have shape-memory characteristics. In an example embodiment, one or more shrink fittings600,602,604,606may include one or more alloys of approximately 50% titanium and approximately 50% nickel, known as Nitinol and/or Tinel, as discussed above. In addition or in the alternative, the one or more alloys may include, for example, one or more other alloying materials, such as niobium, as also discussed above.

One or more shrink fittings600,602,604,606may include many geometries. For example, one or more shrink fittings600,602,604,606may be generally round (i.e., circular, oval-shaped, rounded, curved). In an example embodiment, one or more shrink fittings600,602,604,606are shrink rings available, for example, from Memry Corporation.

Spool piece500may include one or more grooves, ridges, lips, etc. on its outer surface near one or both ends506,508. Similarly, sleeve510,512may include one or more grooves, ridges, lips, etc. on its inner surface. When sleeve510,512act on spool piece500and ends302,304of the submerged line to fix or help fix spool piece500to ends302,304, the one or more grooves, ridges, lips, etc. on the outer surface of spool piece500and/or the one or more grooves, ridges, lips, etc. on the inner surface of sleeve510,512may improve contact between sleeve510,512and ends506,508of spool piece500, and/or improve contact between sleeve510,512and ends302,304of the submerged line.

In addition or in the alternative, sleeve510,512may include one or more grooves, ridges, lips, etc. on its outer surface. Similarly, one or more shrink fittings600,602,604,606may include one or more grooves, ridges, lips, etc. on their inner surface. When one or more shrink fittings600,602,604,606act on sleeve510,512, the one or more grooves, ridges, lips, etc. on the outer surface of sleeve510,512and/or the one or more grooves, ridges, lips, etc. on the inner surface of one or more shrink fittings600,602,604,606may improve contact between sleeve510,512and one or more shrink fittings600,602,604,606, improve contact between sleeve510,512and ends506,508of spool piece500, and/or improve contact between sleeve510,512and ends302,304of the submerged line.

The one or more grooves may include, for example, one or more spiral grooves, one or more parallel grooves, and/or one or more circumferential grooves. The one or more grooves may or may not be continuous. The one or more ridges may include, for example, one or more spiral ridges, one or more parallel ridges, and/or one or more circumferential ridges. The one or more ridges may or may not be continuous. The one or more lips may or may not be continuous.

Sleeve510,512may be disposed on spool piece500in the position(s) shown inFIG. 5prior to spool piece500being disposed adjacent to corresponding ends302,304of the submerged line. In addition or in the alternative, sleeve510,512may be disposed elsewhere on spool piece500(or on end302and/or end304of the submerged line), and then disposed in the position(s) shown inFIG. 5after spool piece500is disposed adjacent to corresponding ends302,304of the submerged line.

In addition or in the alternative, one or more shrink fittings600,602,604,606may be disposed on sleeve510,512in the position(s) shown inFIG. 6prior to spool piece500being disposed adjacent to corresponding ends302,304of the submerged line and/or prior to sleeve510,512being fitted over ends506,508of spool piece500and corresponding ends302,304of the submerged line. In addition or in the alternative, one or more shrink fittings600,602,604,606may be disposed elsewhere on spool piece500or elsewhere on sleeve510,512(or on end302and/or end304of the submerged line), and then disposed in the position(s) shown inFIG. 6after spool piece500is disposed adjacent to corresponding ends302,304of the submerged line and/or after sleeve510,512is fitted over ends506,508of spool piece500and corresponding ends302,304of the submerged line.

Connecting the spool piece may include: connecting a body to one of the support brackets; and/or fixing the spool piece to the body.

One or more support brackets202may include, for example, a base and two or more fingers extending from the base. The fingers may include many geometries. For example, the fingers may approximate the shape of one or more rectangular solids.

FIG. 7is a perspective view of body700, according to an example embodiment.FIG. 8is a front view of body800, according to another example embodiment.FIG. 9is a front view of body900, according to yet another example embodiment.FIG. 10is a perspective view of body1000, according to still another example embodiment.

Body700may be designed, for example, so that it may be connected to one of support brackets202by fitting at least a portion of body700onto one or more of the fingers and/or by fitting at least a portion of body700in between two or more of the fingers.

Body700may include many geometries. For example, portions of body700may approximate the shape of a rectangular solid, a ball, or a disk. In an example embodiment, first portion802of body800may approximate the shape of the letter “U” in one dimension so that, when viewed from the end opposite the tines of the “U,” the cross-section of first portion802approximates a rectangular shape, as shown inFIG. 8. In another example embodiment, first portion902of body900may approximate the shape of the letter “U” in two dimensions so that, when viewed from the end opposite the tines of the “Us,” the cross-section of first portion902approximates a cruciform shape, as shown inFIG. 9. In yet another example embodiment, first portion1002of body1000may approximate the shape of a cylinder, in whose surface two axial grooves1004,1006have been formed, so that, when viewed from an axial direction, the cross-section of first portion1002may approximate the shape of the letter “I,” as shown inFIG. 10.

One or more interior surfaces of body700,800,900,1000may be sized, shaped, and/or oriented to facilitate connecting body700,800,900,1000to support bracket202, fitting at least part of body700,800,900,1000onto one or more of the fingers, and/or fitting at least part of body700,800,900,1000in between two or more of the fingers.

FIG. 11is a side view of support bracket202, showing body700and body1100connected to support bracket202. At least part of body700may fit onto one or more of the fingers. At least part of body1100may fit in between two or more of the fingers. One or more shrink fittings1102may connect body700to support bracket202. One or more shrink fittings1104may connect body1100to support bracket202. Spool piece1106may be connected to support bracket202by body700and/or one or more shrink fittings1102. Spool piece1108may be connected to support bracket202by body1100and/or one or more shrink fittings1104.

In an example embodiment, first portion702of body700may approximate the shape of the letter “U” in one dimension so that, when viewed from the end opposite the tines of the “U,” the cross-section approximates a rectangular shape. Inner surfaces704and/or706of body700may facilitate connecting body700to support bracket202, as shown inFIG. 11(i.e., inner surfaces704and706may substantially match the shape of outer surfaces of the fingers of support bracket202). In addition or in the alternative, second portion708and/or third portion710of body700may facilitate connecting body700to support bracket202, as also shown inFIG. 11(i.e., second portion708and/or third portion710may allow body700to flex open so that body700fits onto one or more of the fingers relatively easily and/or to flex closed so that body700connects tightly to support bracket202).

Body700may be designed to be connected to support bracket202using one or more shrink fittings acting on body700. In an example embodiment, body700may include one or more surfaces712,714that facilitate this connection. For example, one or more surfaces712,714may be sized, shaped, and/or oriented to accept the one or more shrink fittings. In an example embodiment, one or more surfaces712,714may be rounded to accept one or more shrink fittings. In another example embodiment, one or more surfaces712,714may include one or more lips716,718to retain one or more shrink fittings. In yet another example embodiment, the one or more surfaces may include one or more grooves (not shown) to accept and retain one or more shrink fittings. In each of these example embodiments, the one or more shrink fittings may include one or more shrink rings.

Body700may include one or more sites720for fixing the spool piece to body700without welding. One or more sites720may be sized, shaped, and/or oriented to accept the spool piece. In addition or in the alternative, one or more sites720may be sized, shaped, and/or oriented to accept one or more shrink fittings.

The spool piece may be associated with at least one of one or more sites720. Prior to fixing the spool piece to body700(and/or prior to connecting body700to support bracket202), spool piece may be moved axially relative to the at least one of one or more sites720. This axial movement allows the spool piece to be, for example, fitted over corresponding ends302,304of the submerged line from which the damaged section was cut out or disposed adjacent to corresponding ends302,304of the submerged line, instead of being fitted over them. After the spool piece is fitted over or disposed adjacent to corresponding ends302,304of the submerged line, the spool piece may be fixed to the body by one or more shrink fittings acting on the at least one of one or more sites720.

In an example embodiment, one or more sites720may include one or more collets724. One or more collets724may be sized, shaped, and/or oriented to accept the spool piece. In addition or in the alternative, one or more collets724may be sized, shaped, and/or oriented to accept one or more shrink fittings. One or more collets724may include two or more kerf cuts726.

The spool piece may be threaded through at least one of one or more collets724. Prior to fixing the spool piece to body700(and/or prior to connecting body700to support bracket202), the spool piece may be moved axially within one or more collets724. This axial movement allows the spool piece to be, for example, fitted over corresponding ends302,304of the submerged line from which the damaged section was cut out or disposed adjacent to corresponding ends302,304of the submerged line, instead of being fitted over them. After the spool piece is fitted over or disposed adjacent to corresponding ends302,304of the submerged line, the spool piece may be fixed to body700by one or more shrink fittings acting on the at least one of one or more collets724.

In an example embodiment, fourth portion722of body700may include collet724, as shown inFIG. 7. Collet724may include multiple kerf cuts726, also as shown inFIG. 7. Collet724may be sized, shaped, and/or oriented to accept the spool piece. In addition or in the alternative, collet724may be sized, shaped, and/or oriented to accept a shrink fitting. The shrink fitting may be a shrink ring.

End728of body700may or may not be solid. For example, end728of body700may include an indentation or aperture (not shown) that can accommodate a finger of support bracket202.

Body1000may include one or more sites1008for fixing a spool piece to body1000without welding. One or more sites1008may be sized, shaped, and/or oriented to accept the spool piece. In addition or in the alternative, one or more sites1008may be sized, shaped, and/or oriented to accept one or more shrink fittings. The one or more shrink fittings may act on one or more sites1008or on the spool piece and one or more sites1008.

FIG. 12is a diagram illustrating body1200and spool piece1202, according to an example embodiment. Body1200may include two sites1204,1206for fixing spool piece1202to body1200without welding. Sites1204,1206may be sized, shaped, and/or oriented to accept spool piece1202. In addition or in the alternative, sites1204,1206may be sized, shaped, and/or oriented to accept one or more shrink fittings1208,1210. One or more shrink fittings1208,1210may act on sites1204,1206or on spool piece1202and sites1204,1206.

Body700,800,900,1000,1100,1200may include, for example, one or more materials used in construction of a nuclear reactor. Body700,800,900,1000,1100,1200may include, for example, one or more high-strength alloys used in construction of a nuclear reactor. Body700,800,900,1000,1100,1200may include, for example, one or more stainless steels (i.e., Type 304, Type 316, and/or Type XM19) and/or one or more nickel-chromium-iron alloys (i.e., Inconel™ X750).

In another example embodiment, methods of repairing nuclear reactors that include one or more submerged lines welded to one or more support brackets may include: removing one or more damaged sections of the one or more submerged lines; and/or replacing the one or more damaged sections of the one or more submerged lines without welding.

In yet another example embodiment, methods of operating nuclear reactors that include one or more submerged lines welded to one or more support brackets may include: shutting down the nuclear reactor; repairing damage to at least one of the one or more submerged lines without welding; and/or starting up the nuclear reactor.

As discussed above, repairing damage to the at least one of the one or more submerged lines may include: removing a damaged section of a submerged line welded to at least one of the one or more support brackets; and/or replacing the damaged section of the submerged line.

The damage to at least one of the one or more submerged lines may be repaired after the nuclear reactor is shut down and before the nuclear reactor is started up. Depending on the condition of the nuclear reactor, at least portion of the repair may begin before the nuclear reactor is shutdown or at least portion of the repair may begin while the nuclear reactor is being shut down.

In still another example embodiment, methods of operating nuclear reactors that include one or more submerged lines welded to one or more support brackets may include: cooling down the nuclear reactor; repairing damage to at least one of the one or more submerged lines without welding; and/or heating up the nuclear reactor.

The damage to at least one of the one or more submerged lines may be repaired after the nuclear reactor is cooled down and before the nuclear reactor is heated up. Depending on the condition of the nuclear reactor, the repair may be conducted without cooling down the nuclear reactor, at least portion of the repair may begin before the nuclear reactor is cooled down, or at least portion of the repair may begin while the nuclear reactor is being cooled down. The nuclear reactor may be cooled down, for example, to less than 400° F., 350° F., 300° F., 250° F., 212° F., 200° F., 175° F., 150° F., 125° F., 100° F., and/or 75° F. Heatup of the nuclear reactor may facilitate the changing of dimension(s), contraction, phase change, and/or shape-memory characteristics.

Although repairing damage to the submerged lines may be more difficult with flow through the nuclear reactor, the damage to at least one of the one or more submerged lines may be repaired under various flow conditions, including flow through one or more recirculation pumps and/or flow through one or more jet pump assemblies138.

In a further example embodiment, apparatuses for repairing nuclear reactors that include one or more submerged lines welded to one or more support brackets may include: the body, discussed above, including one or more sites for fixing a spool piece to the body without welding.

In another further example embodiment, apparatuses for repairing nuclear reactors that include one or more submerged lines welded to one or more support brackets may include: the spool piece, discussed above; and/or the body, discussed above, including one or more sites for fixing the spool piece to the body without welding.

A kit for repairing nuclear reactors that include one or more submerged lines welded to one or more support brackets may include: the body, discussed above, including one or more sites for fixing a spool piece to the body without welding. In addition or in the alternative, the kit may include the spool piece, discussed above; and/or the body, discussed above, including one or more sites for fixing the spool piece to the body without welding. In addition or in the alternative, the kit may include the spool piece, the body (with two shrink fittings), and/or two couplings (with two sleeves and/or four shrink fittings).

FIG. 13is a first perspective view of a repair conducted using a body and two shrink fittings, as well as a spool piece and two couplings (two sleeves and four shrink fittings), similar to that ofFIG. 6, according to an example embodiment.FIG. 14is a second, closer perspective view of the repair ofFIG. 13.