Abstract:
Modular flow control systems include several differently-shaped structures to achieve desired flow characteristics in fluid flow. Systems include one or many plates held in desired positions by a retainer within the flow. The plates are uniquely shaped based on their position, or vice versa, to shape flow in a desired manner. The plates may fill an entire flow area or may extend partially throughout the area. Plates can take on any shape and are useable in systems installed in any type of flow conduit. When used in a PCCS upper manifold in a nuclear reactor, a chevron plate directly below the inlet divides flow along the entire upper manifold. Perforated plates allow flow to pass at ends of the PCCS upper manifold. The plates can be installed along a grooved edge during an access period and held in static position by filling the length of the PCCS upper manifold.

Description:
BACKGROUND 
       [0001]      FIG. 1  is a cross-section of a related art Passive Containment Cooling System (PCCS)  10 , such as a PCCS  10  useable in an ESBWR or other type of nuclear power plant. For example, PCCS  10  may be submerged in a coolant source like a PCCS pool inside or near a nuclear reactor containment building. As shown in  FIG. 1 , PCCS  10  may include an inlet  15  that receives steam, heated water, noncombustible gasses, and/or other energetic fluids that may accumulate in a nuclear reactor containment or other power production environment. For example, inlet  15  may include an opening into a nuclear power plant containment that receives such fluids and delivers the fluids to related art PCCS  10 . Inlet  15  flows into an upper manifold  11 , which may be a large, voided drum or other fluid-receiving structure. One or more end plates  19  may be bolted to upper manifold  11  to close ends of upper manifold  11  for fluid containment. 
         [0002]    Upper manifold  11 , in turn, connects to several vertical PCCS tubes  12  below upper manifold  11 . Fluid may be distributed in manifold  11  and flow into PCCS tubes  12 , under gravity and/or energy from inlet  15 . Because PCCS tubes  12  may be submerged in a coolant, like chilled water, the increased surface area of PCCS tubes  12  may cool and/or condense fluid received into PCCS  10 . Such cooling and condensation in PCCS tubes  12  may further drive the fluid downward into lower manifold  13 . Condensed liquid collecting down into lower manifold  13  may flow out through an outlet  14  of PCCS  10 . Additional details of related art PCCS structures are described in co-owned US Patent Publication 2015/0146839 to Marquino et al., the entirety of which is incorporated herein by reference in its entirety. 
       SUMMARY 
       [0003]    Example embodiments include systems to control fluid flow in a flow path of an open or closed volume. Example systems use several swappable plates that can be positioned at desired sequences or intervals in the flow. The plates have varying surfaces that interact with and/or direct the flow in desired ways. A retainer holds the various plates in position, achieving the desired flow. For example, plates may mate with a retaining edge extending a length of the flow volume, and plates may be a width of the flow volume, such that when the length of the retaining edge is filled with the plates, the entire flow area may be filled. Plates can present a variety of geometries, including perforations, labyrinthine passages, chevrons, voids, mixing tabs, swirl vanes, and solid, flat planes to enhance, impede, make turbulent, mix, direct, and/or change fluid flow. Plates can be placed in positions in the volume based on their geometries and effect on flow to achieve desired flows. For example, a chevron plate may be placed directly below an inlet for a high-velocity and high-temperature steam and non-condensable gas mixture in a PCCS upper manifold, and the chevron plate may deflect and redirect the flow to diffuse it along an entire length of the upper manifold. 
         [0004]    Example methods include installing modular fluid flow control systems in areas subject to fluid flow. Different plates can be placed at different positions within the volume to achieve desired flow. For example, a plate with a chevron and a plate with several perforations may be slid into a retaining edge that allows single-dimensional movement of the plates until the volume is full. The retainer to hold the plates may be separately installed in the volume or may already be present. In example methods plates may be swapped, removed, or added because they are modular, in order to achieve desired flow characteristics. 
     
    
     
       BRIEF DESCRIPTIONS OF THE DRAWINGS 
         [0005]    Example embodiments will become more apparent by describing, in detail, the attached drawings, wherein like elements are represented by like reference numerals, which are given by way of illustration only and thus do not limit the terms which they depict. 
           [0006]      FIG. 1  is an illustration of a related art passive containment cooling system (PCCS). 
           [0007]      FIG. 2  is an illustration of a PCCS upper manifold modified in accordance with example methods. 
           [0008]      FIG. 3  is an illustration of an example embodiment modular fluid diverter system. 
           [0009]      FIG. 4  is an illustration of an example embodiment modular fluid diverter system installed in a PCCS upper manifold. 
       
    
    
     DETAILED DESCRIPTION 
       [0010]    Because this is a patent document, general broad rules of construction should be applied when reading and understanding it. Everything described and shown in this document is an example of subject matter falling within the scope of the appended claims. Any specific structural and functional details disclosed herein are merely for purposes of describing how to make and use example embodiments or methods. Several different embodiments not specifically disclosed herein fall within the claim scope; as such, the claims may be embodied in many alternate forms and should not be construed as limited to only example embodiments set forth herein. 
         [0011]    It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
         [0012]    It will be understood that when an element is referred to as being “connected,” “coupled,” “mated,” “attached,” or “fixed” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between”, “adjacent” versus “directly adjacent”, etc.). Similarly, a term such as “communicatively connected” includes all variations of information exchange routes between two devices, including intermediary devices, networks, etc., connected wirelessly or not. 
         [0013]    As used herein, the singular forms “a”, “an” and “the” are intended to include both the singular and plural forms, unless the language explicitly indicates otherwise with words like “only,” “single,” and/or “one.” It will be further understood that the terms “comprises”, “comprising,”, “includes” and/or “including”, when used herein, specify the presence of stated features, steps, operations, elements, ideas, and/or components, but do not themselves preclude the presence or addition of one or more other features, steps, operations, elements, components, ideas, and/or groups thereof. 
         [0014]    It should also be noted that the structures and operations discussed below may occur out of the order described and/or noted in the figures. For example, two operations and/or figures shown in succession may in fact be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Similarly, individual operations within example methods described below may be executed repetitively, individually or sequentially, so as to provide looping or other series of operations aside from the single operations described below. It should be presumed that any embodiment having features and functionality described below, in any workable combination, falls within the scope of example embodiments. 
         [0015]    The Inventors have newly recognized that highly energetic fluids, such as saturated steam, combustibles, and super-heated non-condensable gasses, may produce uneven flow distribution in typical PCCS systems when produced in a power plant. For example, during a transient involving a loss of coolant, superheated containment, or other event with highly energetic fluid flows, such fluids may enter a PCCS system  10  ( FIG. 1 ) though an inlet  15  ( FIG. 1 ). Due to the energy of these fluid flows, upper manifold  11  ( FIG. 1 ) may be unable to evenly disperse or diffuse the energetic flow across all PCCS tubes  12  ( FIG. 1 ), thereby reducing the overall efficiency of the PCCS system  10  ( FIG. 1 ). 
         [0016]    The Inventors have further recognized that fluid flow generally, such as in manifolds as well as pipes, vents, drains, etc., may be difficult to easily manage based on different encountered flows. For example, it may be desirable to evenly-distribute a heated flow through a heat exchanger, or it may be desirable to limit flows around sensitive components or change internal flow characteristics for expected destructive flows. However, fluid flow structures are typically statically constructed with simple binary flow on/off controls without finer, easily-implemented control over internal flow characteristics. Example embodiments described below address these and other problems recognized by the Inventors with unique solutions enabled by example embodiments. 
         [0017]    The present invention is systems and methods for modularly adjusting fluid flow through an area. In contrast to the present invention, the small number of example embodiments and example methods discussed below illustrate just a subset of the variety of different configurations that can be used as and/or in connection with the present invention. 
         [0018]      FIG. 2  is an illustration of a PCCS upper manifold  11  modified in accordance with an example system and method. As shown in  FIG. 3 , manifold  11  includes a retainer to hold an example embodiment diverter. For example, a notched or grooved ledge  100  may be affixed to or formed on an inner surface of upper manifold  11 . Grooved ledge  100  may run an entire length of upper manifold  11  or may be partial or discontinuous. Multiple grooved ledges  100  may be used in example embodiments; for example, two opposite grooved ledges  100 , as shown in  FIG. 2 , may be on opposite inner surfaces of upper manifold  11  so as to face one another with grooves opening toward one another. Grooved ledges  100  may be rigid and fabricated of materials known to maintain their physical properties in a nuclear reactor environment. 
         [0019]    Example methods may create retaining structures like grooved ledge  100  through installation or at initial creation of upper manifold  11 . For example, grooved ledges  100  may be installed by welding or bolting during a plant outage or other maintenance period when operators have access to upper manifold  11 . Or, for example, grooved ledge  100  may be integrally formed during the casting and/or shaping of upper manifold  11  so as to always be present in PCCS upper manifold  11 . Although shown installed in an upper manifold  11  of a PCCS system, it is understood that grooved ledge  100  used in connection with example embodiments may be installed in other fluid passages, like pipes or vents. 
         [0020]      FIG. 3  is an illustration of an example embodiment fluid diverter system  200 . As shown in  FIG. 3 , fluid diverter system  200  includes one or more modular plates configured to be retained in a retainer of example methods. For example, fluid diverter system  200  may include several plates all having a tongued-edge  210  that matches and mates with grooved ledge  100  ( FIG. 2 ) on both sides of the plates. In this way, example embodiment fluid diverter system  200  may slide between and be retained by grooved ledge  100  ( FIG. 2 ). Of course, other retaining structures may be used, including dovetails, mechanical interlocks, zippers, magnetized surfaces, locking pieces, etc., to join example embodiment system  200  with a desired flow space, such as upper manifold  11  ( FIG. 2 ). Similarly, while example system  200  may use a sliding structure to allow single-dimensional movement of modular plates that are locked in place by adjacent plates and/or interior surfaces, it is understood that other loading structures, like grooves, ratchets, chains, springs, adhesives, tangs-and-slots, etc. may be used to selectively move and retain plates in desired positions with respect to fluid flow. 
         [0021]    Example embodiment fluid diverter system  200  may include different types of plates to selectively manage flow where system  200  is employed. For example, example embodiment system may be installed such that largest surfaces of system  200  are perpendicular throughout a fluid flow through a volume, requiring fluid flow substantially interact with system  200 . Alternately, example embodiment fluid diverter system  200  may be angled or placed at any other orientation with respect to expected fluid flow. Various plates may be installed and retained in example embodiment system  200  at expected positions and orientations of fluid flow to control the fluid flow in any desired manner. 
         [0022]    For example, as shown in  FIG. 3 , example embodiment flow diverter system  200  may include a chevron plate  201  with oppositely-wedged or curved surfaces  211 . Chevron plate  201  may divide and/or redirect an energetic flow encountering opposite surfaces  211  in order to redistribute or separate fluid flows. Example system  200  may similarly include a blocking plate  203 , which is substantially solid and blocks relatively all flow therethrough. As fluid encounters solid plate  203  perpendicular to flow, such flow may be stopped; similarly, where solid plate  203  is encountered at an angle, such flow may become angled as well. Example system  200  may include a perforated plate  204  that includes one or more holes  214  positioned and dimensioned to allow only a desired amount or location of fluid flow through perforated plate  203 . Sufficiently small holes  214  may further limit fluid flow through frictional forces as well as reduced flow area, and holes  214  may be specifically positioned, such as at an edge or in a gradient, to control and shape fluid flow through perforated plate  204 . Example embodiment system  200  may also include a voided plate or separator plate  202  that minimally obstructs flows while separating or positioning adjacent plates. For example, separator plate  202  may contain 95% or more open flow area, while perforated plate  203  may have less than 95% open flow area created by holes  214 . 
         [0023]    Because plates  201 ,  202 ,  203 , and  204  may all have similar widths terminating at tongued edges  210  that mate into a retainer in a flow passage, any of plates  201 ,  202 ,  203 , and  204  may equally fit in a same flow passage, such as by being slid lengthwise into a same grooved edge  100  ( FIG. 2 ). That is, plates  201 ,  202 ,  203 , and  204  may be modular within example systems. As shown in  FIG. 3 , plates  201 ,  202 ,  203 , and  204  may directly abut one another at length ends of each plate when installed. Further, plates  201 ,  202 ,  203 , and/or  204  may interlock or become removably joined in the length dimension by use of magnets, adhesives, locking joints, fasteners, etc. to prevent fluid flow from significantly escaping between plates. 
         [0024]    Plates  201 ,  202 ,  203 , and/or  204  may be mixed and matched along a length of example system  200  when installed in a flow path. That is, any of plates  201 ,  202 ,  203 , and  204  may be selected for a particular length position to achieve desired fluid flow at that position. As shown in  FIG. 3 , for example, perforated plates  204  may be positioned at length ends of example system  200 , separated by separator plates  202 . Depending on sizing and numerosity of holes  214  as well as widths of separator plates  202 , fluid may flow relatively easily through length ends of example embodiment system  200 . Chevron plate  201  and/or solid plates  203  may occupy more central locations, which may both divert and block fluid from flowing through central length portions of example embodiment flow diverter system  200 . Of course, other arrangements with different numbers, orders, and individual characteristics of plate(s) are useable in example systems outside of the sequence shown in  FIG. 3 . 
         [0025]      FIG. 4  is an illustration of an example embodiment flow diverter system  200  as installed in an upper manifold  11  of a PCCS system. In example methods, end plates  19  of PCCS upper manifold  11  may be removed during a maintenance or outage period, allowing access to an interior of upper manifold  11 . One or more plates of example system  200  may be installed in retainers in manifold  11  while end plate  19  is removed. For example, plates may be slid in grooved ledges  100  at either side of manifold  11  as shown in  FIG. 2  via tongued edges  210 . When a desired number and sequence of plates are installed, end plate  19  may be reaffixed to manifold  11 , sealing the same. 
         [0026]    As shown in  FIG. 4 , in one example embodiment, chevron plate  201  may be positioned directly below inlet  15  of a PCCS system. In this way, energetic flows of saturated steam and/or non-condensable or noncombustible gasses from inlet  15  may be diverted by chevron plate  201  along a length of example embodiment system and thus upper manifold  11 . One or more blocking plates  203  directly at both sides of chevron plate  201  may further enhance the diversion and/or diffusion of the energetic flow along a length of upper manifold  11 . Then perforated plates  204  and separator plates  202  may be positioned at lengthwise ends of example embodiment system  200 . Perforated plates  204  and separator plates  202  may permit substantially more fluid flow into PCCS tubes  12  directly vertically below perforated plates  204  and separator plates  202 . All plates in example embodiment flow diverter system  200  may directly abut in a lengthwise arrangement and occupy substantially all flow path through manifold  11 . All plates may further be substantially perpendicular to incoming flow from inlet  15 , requiring all fluid flow to interact with example embodiment flow diverter system  200 . 
         [0027]    The sequence of plates shown in the example of  FIG. 4  significantly equalizes energetic fluid flows though all PCCS tubes  12  in a conventional PCCS system. Because chevron plate  201  and/or blocking plates  203  diverts flow away from inlet  15  lengthwise, energetic flow cannot overwhelm central PCCS tubes  12  directly below inlet  15 . Further, because perforated plates  204  allow more flow at ends of upper manifold  11 , PCCS tubes  12  at lengthwise ends of manifold  11  may receive larger amounts of flows, preventing backflows or circular flows though PCCS systems. Moreover, because plates in example embodiment system  200  are modular and may be relatively easily installed, removed, and/or swapped with other plates having desired flow characteristics such as chevrons, holes, or voids, levels and distributions of flows in upper manifold  11  can be fine-tuned and controlled to achieve desired flows simply by replacing or moving plates with particular characteristics to desired positions. 
         [0028]    Example embodiments and methods thus being described, it will be appreciated by one skilled in the art that example embodiments may be varied and substituted through routine experimentation while still falling within the scope of the following claims. For example, a variety of different fluid flow structures aside from PCCS manifolds are compatible with example embodiments and methods simply through proper dimensioning of example embodiments and fall within the scope of the claims. Such variations are not to be regarded as departure from the scope of these claims.