Description:TECHNICAL FIELD
[0001] The present disclosure described herein relates to a steam generator of a nuclear power plant.
[0002] In particular, the present disclosure relates to modifications and changes in design configurations of a feed liquid pipeline system in a nuclear steam generator for eliminating in-service inspection during the service periods without affecting the performance of the nuclear steam generator.
BACKGROUND
[0003] A steam generator is a heat exchanger used to generate steam from the available process liquid. The steam is then used to drive a turbine and generate electricity. In a nuclear power plant, a drum-type pressurized heavy water reactor (PHWR) nuclear steam generator is commonly used. Basically, in such a steam generator high pressurized primary liquid (generally heavy water) is passed through a U-tube bundle, where it transfers its heat (via conduction through metal) to lower-pressure secondary liquid (generally water) which is allowed to boil and converted into steam. The secondary liquid is supplied by a feed liquid pipeline system of the PHWR nuclear steam generator. FIG. 1 shows an existing structure of a feed liquid pipeline system 100 of a PHWR nuclear steam generator (not shown) of a nuclear power plant. The feed liquid pipeline system 100 is located below an upper deck plate region (not shown in FIG. 1) of the PHWR nuclear steam generator. The feed liquid pipeline system 100 comprises a feed liquid nozzle 102, bends 104 of 90 and 180-degree, connecting pipes 106a, 106b, guiding plate 108, bellows 110, connecting structure 112, and a ring header assembly 114. The feed liquid nozzle 102 is connected with the connecting pipe 106a with the help of bends 104. The connecting pipe 106b is connected with the connecting structure 112 that is inclined and conical in shape. The bellows 110 are provided between the connecting pipe 106a and 106b. The bellows 110 are of two-ply of 0.6mm thickness of convolutes made up of stainless steel (SS). The ring header assembly 114 is placed below the connecting structure 112. The ring header assembly 114 comprises a ring pipe 114a with 92 welded J-tubes (not shown in FIG. 1), spacer plates 114b that support the ring pipe 114a, a pair of fasteners 114c, and a support plate 114d. In an aspect, the ring header assembly 114 is located below a lower deck plate region of the PHWR nuclear steam generator. In an aspect, the diameter of the ring pipe 114a and the thickness of the support plate 114d is 219.1mm and 50mm respectively. The support plate 114d is placed below the ring header assembly 114 such that the position of the support plate 114d is also below the lower deck plate region of the PHWR nuclear steam generator. In the ring header assembly 114, the feed liquid (generally water) is injected through the J-tubes into a down-corner region of the PHWR nuclear steam generator. The design intent of feed liquid pipeline system 100 is to distribute the secondary liquid evenly between an inner shell of the PHWR nuclear steam generator and the down-comer region by providing differential expansion of the bellows 110 taking place in different operating conditions like full power load, start/shut down, cold liquid injection, etc. However, the problem with the existing feed liquid pipeline system 100 is that an operator is unable to inspect the bellows 110 as the position of the bellows 110 is inaccessible for the in-service inspection.
[0004] Therefore, there is a need to provide a solution that obviates the above-mentioned problem.
OBJECTS OF THE DISCLOSURE
[0005] Some of the objects of the present disclosure, which at least one embodiment herein satisfy, are listed hereinbelow.
[0006] It is a general or primary object of the present disclosure to provide a steam generator of a nuclear power plant with an improved or modified feed liquid pipeline system that doesn’t require in-service inspection during operating conditions.
[0007] It is a further object of the present disclosure to provide a steam generator of a nuclear power plant with an improved or modified feed liquid pipeline system that is easy to fabricate.
[0008] These and other objects and advantages will become more apparent when reference is made to the following description and accompanying drawings.
SUMMARY
[0009] This summary is provided to introduce concepts related to a steam generator of a nuclear power plant. The concepts are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
[0010] The subject matter disclosed herein relates to a steam generator of a nuclear power plant. The steam generator comprises a feed liquid pipeline system located below an upper deck plate region of the steam generator. The feed liquid pipeline system comprises a single connecting pipe that connects a feed liquid nozzle with a straight and cylindrical connecting structure and a ring header assembly placed below the cylindrical connecting structure such that the position of the ring header assembly is aligned with a lower deck plate region of the steam generator.
[0011] In an aspect, the connecting pipe is connected with the feed liquid nozzle with the help of bends of 90 and 180-degree.
[0012] In an aspect, the ring header assembly comprises a ring pipe having a diameter of 275.1mm.
[0013] In an aspect, the ring header assembly comprises a support plate having a thickness of 60mm.
[0014] In an aspect, the support plate is placed below the ring header assembly such that the position of the support plate is aligned with the lower deck plate region of the steam generator.
[0015] The disclosed feed liquid pipeline system doesn’t comprise bellows and further, the position of the ring header assembly and the support plate is changed as compared to the existing feed liquid pipeline system shown in FIG. 1, the in-service inspection is eliminated.
[0016] To further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit the scope of the present subject matter.
[0017] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] It is to be noted, however, that the appended drawings illustrate only typical embodiments of the present subject matter and are therefore not to be considered for limiting of its scope, for the invention may admit to other equally effective embodiments. The detailed description is described with reference to the accompanying figures. The illustrated embodiments of the subject matter will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and methods that are consistent with the subject matter as claimed herein, wherein:
[0019] FIG. 1 illustrates an existing feed liquid pipeline system of a steam generator of a nuclear power plant; and
[0020] FIG. 2 illustrates a steam generator of a nuclear power plant having a modified feed liquid pipeline system in accordance with the present disclosure.
[0021] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION
[0022] The detailed description of various exemplary embodiments of the disclosure is described herein with reference to the accompanying drawings. It should be noted that the embodiments are described herein in such details as to communicate the disclosure. However, the amount of details provided herein is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0023] It is also to be understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and embodiments of the present disclosure, as well as specific examples, are intended to encompass equivalents thereof.
[0024] The terminology used herein is to describe particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context indicates otherwise. It will be further understood that the terms “comprises”, “comprising”, “includes” and/or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof.
[0025] It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
[0026] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
[0027] In the following detailed description of the embodiments of the disclosure, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration specific embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present disclosure. The following description is, therefore, not to be taken in a limiting sense.
[0028] Hereinafter, a description of an embodiment with several components in communication with each other does not imply that all such components are required. On the contrary, a variety of optional components are described to illustrate the wide variety of possible embodiments of the present disclosure.
[0029] Reference is made to FIG. 2 showing a steam generator 200 of a nuclear power plant. In an aspect, the steam generator 200 is a drum-type pressurized heavy water reactor (PHWR) steam generator. The constructional features and their functioning of the steam generator 200 are already known and are, therefore, not discussed herein for the sake of brevity. The steam generator 200 comprises at least two feed liquid pipeline system 202 located below an upper deck plate region 200-1a with a modified design that eliminates the need for in-service inspection.
[0030] Each one of the feed liquid pipeline system 202 comprises a feed liquid nozzle 204, bends 206 of 90 and 180-degree, connecting pipe 208, guiding plate 210, connecting structure 212, and a ring header assembly 214. The presently disclosed feed liquid pipeline system 202 doesn’t comprise bellows that eliminate the need for in-service inspection. Although the absence of bellows would introduce a higher stress level compared to the existing feed liquid pipeline system 100 with bellows, it is found that levels of stress are within code mandated acceptable limits. Further unlike the feed liquid pipeline system 100 shown in FIG. 1 that comprises two connecting pipes 106a and 106b, a single connecting pipe 208 is used in the feed liquid pipeline system 202 that connects the feed liquid nozzle 204 with the connecting structure 212. In an aspect, the connecting pipe 208 is connected with the feed liquid nozzle 204 with the help of bends 206 of 90 and 180-degree. Since only a single connecting pipe 208 is used the number of weld joints is reduced that eases the fabrication of the feed liquid pipeline system 202. The connecting structure 212 is cylindrical and straight or not inclined unlike the connecting structure 112 of the existing feed liquid pipeline system 100. The ring header assembly 214 is placed below the cylindrical connecting structure 212 such that the position of the ring header assembly 214 is aligned with a lower deck plate region 200-1b of the steam generator 200. In an aspect, the position of the ring header assembly 214 is shifted upwards such that the difference between the position of the ring header assembly 114 and the ring header assembly 214 is 0.5m. The upward placement of the ring header assembly 214 eliminates thermal elongation and reduces stress levels in the bends 206 of the feed liquid pipeline system 202 in operating conditions. The ring header assembly 214 comprises a ring pipe 214a with 92 welded J-tubes (not shown in FIG. 2), spacer plates 214b that support the ring pipe 214a, a pair of fasteners 214c, and a support plate 214d. In an aspect, the diameter of the ring pipe 214a and the thickness of the support plate 214b is 275.1mm and 60mm, respectively. The support plate 214d is placed below the ring header assembly 214 such that the position of the support plate 214d is also aligned with the lower deck plate region 200-1b of the steam generator 200. The feed liquid pipeline system 202 is more symmetrical and easy to fabricate than the feed liquid pipeline system 100 shown in FIG. 1.
TECHNICAL ADVANTAGES
[0031] The present disclosure provides a steam generator of a nuclear power plant with an improved or modified feed liquid pipeline system that doesn’t require in-service inspection during operating conditions.
[0032] The present disclosure provides a steam generator of a nuclear power plant with an improved or modified feed liquid pipeline system that is easy to fabricate.
[0033] While the foregoing describes various embodiments of the present disclosure, other and further embodiments of the present disclosure may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The present disclosure is not limited to the described embodiments, versions, or examples, which are included to enable a person having ordinary skill in the art to make and use the present disclosure when combined with information and knowledge available to the person having ordinary skill in the art.

Claims:1. A steam generator (200) of a nuclear power plant, the steam generator (200) comprising:
a feed liquid pipeline system (202) located below an upper deck plate region (200-1a) of the steam generator (200), the feed liquid pipeline system (202) comprising:
a single connecting pipe (208) that connects a feed liquid nozzle (204) with a straight and cylindrical connecting structure (212), and
a ring header assembly (214) placed below the connecting structure (212) such that the position of the ring header assembly (214) is aligned with a lower deck plate region (200-1b) of the steam generator (200).
2. The steam generator (200) as claimed in claim 1, wherein the connecting pipe (208) is connected with the feed liquid nozzle (204) with the help of bends (206) of 90 and 180-degree.

3. The steam generator (200) as claimed in claim 1, wherein the ring header assembly (214) comprises a ring pipe (214a) having a diameter of 275.1mm.

4. The steam generator (200) as claimed in claim 1, wherein the ring header assembly (214) comprises a support plate (214d) having a thickness of 60mm.

5. The steam generator (200) as claimed in claim 4, wherein the support plate (214d) is placed below the ring header assembly (214) such that the position of the support plate (214d) is aligned with the lower deck plate region (200-1b) of the steam generator (200).