Patent Application
20200395135
Example methods and embodiments include pressure vessels, such as nuclear reactor pressure vessels housing a core for electricity generation with integral, valved penetrations passing entirely through the wall of the pressure vessel. The valved penetrations allow control of flow paths through the reactor, such as a primary coolant or ICS loop, without the need for external flanges, mechanical connections, bolts, spot welds, etc., as there is minimal risk of continuous pressure vessel material breaking. Every vessel penetration may use integral valve penetrations to further minimize risk. An extension from the vessel wall may house the valve structures and flow path, and the valve may with a moveable gate in the flow path with external actuator for moving the same to desired open or closed positions. The flow path may extend both along and into the extension, so as to preserve wall thickness and provide a length for valve gate and actuator positioning along the extension. Any number or type of gates may be used, including ball and swing gates. Example methods form the penetrations by creating the flow path through the vessel wall and placing the valve gates directly into the channel in the wall. The wall may be built outward into the extension at the penetration by forging or welding additional plates or segments integrally to the wall and machining the channel through the extension. Additional passages for gate valves and/or actuators may be machined into the extensions as well.
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 example embodiments herein.
Because this is a patent document, general broad rules of construction should be applied when reading it. Everything described and shown in this document is an example of subject matter falling within the scope of the claims, appended below. Any specific structural and functional details disclosed herein are merely for purposes of describing how to make and use examples. Several different embodiments and methods not specifically disclosed herein may 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 examples set forth herein.
Modifiers “first,” “second,” “another,” etc. may be used herein to describe various items, but they do not confine modified items to any order. These terms are used only to distinguish one element from another; where there are “second” or higher ordinals, there merely must be that many number of elements, without necessarily any difference or other relationship. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element unless an order or difference is separately stated. In listing items, the conjunction “and/or” includes all combinations of one or more of the associated listed items. The use of “etc.” is defined as “et cetera” and indicates the inclusion of all other elements belonging to the same group of the preceding items, in any “and/or” combination(s).
When an element is related, such as by being “connected,” “coupled,” “mated,” “attached,” “fixed,” etc., to another element, it can be directly connected to the other element, or intervening elements may be present. In contrast, when an element is referred to as being “directly connected,” “directly coupled,” etc. 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 and routing between two devices, including intermediary devices, networks, etc., connected wirelessly or not.
As used herein, singular forms like “a,” “an,” and the are intended to include both the singular and plural forms, unless the language explicitly indicates otherwise. Indefinite articles like “a” and “an” introduce or refer to any modified term, both previously-introduced and not, while definite articles like “the” refer to the same previously-introduced term. Possessive terms like “comprises,” “includes,” “has,” or “with” when used herein, specify the presence of stated features, characteristics, steps, operations, elements, and/or components, but do not themselves preclude the presence or addition of one or more other features, characteristics, steps, operations, elements, components, and/or groups thereof. Rather, exclusive modifiers like “only” or “singular” may preclude presence or addition of other subject matter in modified terms.
As used herein, “axial” and “vertical” directions are the same up or down directions oriented along the major axis of a nuclear reactor, often in a direction oriented with gravity. “Transverse” directions are perpendicular to the “axial” and are side-to-side directions at a particular axial height. As used herein, “integral” and “integrally” are defined as “with material continuity and inseparability, including single-piece forged and welded materials at ASME nuclear specifications.” As such, integral connections do not include bare mechanical or compressive joining between pieces, where pieces may be disconnected without internal separation or without cutting or destruction of an individual piece.
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 single operations described below. It should be presumed that any embodiment or method having features and functionality described below, in any workable combination, falls within the scope of example embodiments.
The inventors have recognized that mechanical penetrations present a material seam, or discontinuity, in flow paths across a wall through which a fluid, such as reactor coolant or moderator, may leak. Separate valves joining to these penetrations through bolting or other compressive joints may have several failure modes not seen in integral structures. Moreover, separate valves and piping for the same may require several different components to be shipped, assembled, and disassembled, increasing complexity and cost of manufacture and installation. The inventors have developed example embodiments and methods described below to address these and other problems recognized by the Inventors with unique solutions enabled by example embodiments.
The present invention is pressure vessels with a valved, integral penetration through the vessel, methods of forming the same, and plant systems using the same. In contrast to the present invention, the few 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.
One or more gates 120 extend into flow path 102 to selectively block flow through the same, thereby opening or closing valve hub 111/112/167/168. Gates 120 may be configured in any shape and operation range that permit reliable opening and closing of flow path 102; for example, gates 120 may be swings, balls, wedges, parallel disks, stems, etc., including the various types in IMI NH, “Valves and Systems for Nuclear Industries,” NI Product Range, February 2018, incorporated by reference herein in its entirety. Gates 120 may seat through and/or be captured in, pressure vessel 101 in valve hubs 111/112/167/168, with gaskets, blocking flanges, lubricant, seals, etc. to allow reliable movement without the possibility of leakage, failure, or expulsion from valve hubs 111/112/167/168.
Actuator 121 is connected to one or more gates 120 to move the same between open and closed positions. For example, actuator 121 may be a manual handle directly and integrally connected to gate 120, allowing for manual valve operation. Similarly, actuator 121 may be remote and/or a motor, solenoid, pneumatic, or mechanically-operated actuator, or any other type of actuator, that can reliably open gates 120 from an operator signal or plant system trigger. In this way, one or more gates 120 may allow selective flow through flow path 102, thereby opening or closing valve hubs and penetrations containing the same through reactor vessel 101.
Example methods form integral valves such as those in
Example methods form the flow path and valve channel through machining from the vessel wall, potentially through the hub, creating an integral valved penetration. Any additional valve housings and channels, such as to allow gate passage or capture a gate, may be machined from the vessel wall as well. Of course, such passages may also be formed during forging and additive manufacture. Valve gates, actuators, and other valve structures may be directly cut from the vessel and/or installed in penetrations after forming.
Any piping, such as a main steam leg or feedwater line, connected externally may be integrally formed with the penetration, such as through ASME nuclear welding to form integral structures. Example embodiment valves can thus be manufactured without external flanges or mechanical join points to the vessel but may be vessel components themselves. In this way, example embodiment valves may simply open into the pressure vessel internal, such that the flow path, aside from a gate, does not include any seam or material disruption along its entire path from outside the vessel to inside. And example methods and embodiments provide a way to integrate pressure vessel isolation valves into the vessel itself that is easy to manufacture, eliminates piping between vessel and valves, and enables easier manufacture and transportation of the final assembled vessel component with fewer pieces. Elimination of piping systems for reactor pressure vessel isolation valves also reduces SSC for nuclear plants that would otherwise be necessary to mitigate a large valve break LOCA that cannot happen with integral connections.
Some example embodiments and methods thus being described, it will be appreciated by one skilled in the art that examples may be varied through routine experimentation and without further inventive activity. For example, although a cylindrical pressure vessel with specific types of penetrations is used in some examples, it is understood that other vessels and penetrations are useable with examples. Variations are not to be regarded as departure from the spirit and scope of the example embodiments, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
This application claims priority under 35 U.S.C. § 119 to co-pending U.S. Provisional Application 62/861,328, filed Jun. 14, 2019 and incorporated by reference herein in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62861328 | Jun 2019 | US |
