Patent Application
20220090252
The present technology is related to methods of manufacturing structures, such as parts for use in nuclear reactor systems, from oxide dispersion strengthened (ODS) materials.
Oxide dispersion strengthened (ODS) materials (e.g., alloys) consist of a metal matrix with small oxide particles dispersed within the matrix. ODS materials exhibit good corrosion resistance and mechanical properties at elevated temperatures. Likewise, these materials exhibit good creep resistance as the oxide particles decrease movement of dislocations within the metal matrix.
ODS materials are typically fabricated by ball milling two powders (e.g., a metal powder and an oxide powder) and then compacting the powders into an ingot or similar shape using a powder metallurgy process, such as a hot isostatic pressing (HIP) process. The compacted material is then cold worked or hot worked to give the material a fine-grained structure with increased creep resistance. Finally, the ODS material can be shaped into a desired geometry by cold pressing or other processes that preserve the ODS matrix structure.
However, such an ODS material fabrication process limits the geometry of structures that can be manufactured with the ODS material. For example, heating the ODS material during shaping, or welding multiple parts of ODS material together to form a more complex part, can cause the oxide to come out of solution from the metal material such that the oxide material is less dispersed through the metal matrix, thereby degrading the ODS material properties of the structure. More specifically, heating ODS materials to their recrystallization temperature can change the structure and base mechanical properties of the ODS material, while the oxide dispersion changes with melting and cooling.
Many aspects of the present technology can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale. Instead, emphasis is placed on clearly illustrating the principles of the present technology.
Aspects of the present disclosure are directed generally toward methods of manufacturing structures, such as parts for use in nuclear power generation systems, and associated systems and devices. In several of the embodiments described below, for example, a method of fabricating a part for a nuclear reactor system includes additively manufacturing the part as a monolithic structure from a wire formed of an oxide dispersion strengthen (ODS) material, which includes an oxide material dispersed within a metal material. Specifically, the method can include directing a beam of thermal energy toward the wire to melt the wire, and permitting the melted wire to cool and solidify to form the part such that the oxide material remains substantially dispersed within the metal material.
In some aspects of the present technology, by maintaining the dispersion of the oxide particles within the metal material, the ODS material can retain a good creep resistance, wear-resistance, corrosion resistance, and/or other ODS material property at elevated temperatures—even after fabrication. Moreover, the additive manufacturing method can be used to form parts having complex geometries that cannot be fabricated with conventional manufacturing processes used to form structures of ODS material while also maintaining the properties of the ODS material.
Certain details are set forth in the following description and in
The accompanying Figures depict embodiments of the present technology and are not intended limit its scope unless expressly indicated. The sizes of various depicted elements are not necessarily drawn to scale, and these various elements may be enlarged to improve legibility. Component details may be abstracted in the Figures to exclude details such as position of components and certain precise connections between such components when such details are unnecessary for a complete understanding of how to make and use the present technology. Many of the details, dimensions, angles and other features shown in the Figures are merely illustrative of particular embodiments of the disclosure. Accordingly, other embodiments can have other details, dimensions, angles and features without departing from the present technology. In addition, those of ordinary skill in the art will appreciate that further embodiments of the present technology can be practiced without several of the details described below.
The power module 102 includes a containment vessel 110 (e.g., a radiation shield vessel, or a radiation shield container) that houses/encloses a reactor vessel 120 (e.g., a reactor pressure vessel, or a reactor pressure container), which in turn houses the reactor core 104. The containment vessel 110 can be housed in a power module bay 156. The power module bay 156 can contain a cooling pool 103 filled with water and/or another suitable cooling liquid. The bulk of the power module 102 can be positioned below a surface 105 of the cooling pool 103. Accordingly, the cooling pool 103 can operate as a thermal sink, for example, in the event of a system malfunction.
A volume between the reactor vessel 120 and the containment vessel 110 can be partially or completely evacuated to reduce heat transfer from the reactor vessel 120 to the surrounding environment (e.g., to the cooling pool 103). However, in other embodiments the volume between the reactor vessel 120 and the containment vessel 110 can be at least partially filled with a gas and/or a liquid that increases heat transfer between the reactor vessel 120 and the containment vessel 110.
Within the reactor vessel 120, a primary coolant 107 conveys heat from the reactor core 104 to the steam generator 130. For example, as illustrated by arrows located within the reactor vessel 120, the primary coolant 107 is heated at the reactor core 104 toward the bottom of the reactor vessel 120. The heated primary coolant 107 (e.g., water with or without additives) rises from the reactor core 104 through a core shroud 106 and to a riser tube 108. The hot, buoyant primary coolant 107 continues to rise through the riser tube 108, then exits the riser tube 108 and passes downwardly through the steam generator 130. The steam generator 130 includes a multitude of conduits 132 that are arranged circumferentially around the riser tube 108, for example, in a helical pattern, as is shown schematically in
The steam generator 130 can include a feedwater header 131 at which the incoming secondary coolant enters the steam generator conduits 132. The secondary coolant rises through the conduits 132, converts to vapor (e.g., steam), and is collected at a steam header 133. The steam exits the steam header 133 and is directed to the power conversion system 140.
The power conversion system 140 can include one or more steam valves 142 that regulate the passage of high pressure, high temperature steam from the steam generator 130 to a steam turbine 143. The steam turbine 143 converts the thermal energy of the steam to electricity via a generator 144. The low-pressure steam exiting the turbine 143 is condensed at a condenser 145, and then directed (e.g., via a pump 146) to one or more feedwater valves 141. The feedwater valves 141 control the rate at which the feedwater re-enters the steam generator 130 via the feedwater header 131.
The power module 102 includes multiple control systems and associated sensors. For example, the power module 102 can include a hollow cylindrical reflector 109 that directs neutrons back into the reactor core 104 to further the nuclear reaction taking place therein. Control rods 113 are used to modulate the nuclear reaction, and are driven via fuel rod drivers 115. The pressure within the reactor vessel 120 can be controlled via a pressurizer plate 117 (which can also serve to direct the primary coolant 107 downwardly through the steam generator 130) by controlling the pressure in a pressurizing volume 119 positioned above the pressurizer plate 117.
The sensor system 150 can include one or more sensors 151 positioned at a variety of locations within the power module 102 and/or elsewhere, for example, to identify operating parameter values and/or changes in parameter values. The data collected by the sensor system 150 can then be used to control the operation of the system 100, and/or to generate design changes for the system 100. For sensors positioned within the containment vessel 110, a sensor link 152 directs data from the sensors to a flange 153 (at which the sensor link 152 exits the containment vessel 110) and directs data to a sensor junction box 154. From there, the sensor data can be routed to one or more controllers and/or other data systems via a data bus 155.
In the illustrated embodiment, the system 200 includes a reactor vessel 220 and a containment vessel 210 surrounding/enclosing the reactor vessel 220. In some embodiments, the reactor vessel 220 and the containment vessel 210 can be roughly cylinder-shaped or capsule-shaped. The system 200 further includes a plurality of heat pipe layers 211 within the reactor vessel 220. In the illustrated embodiment, the heat pipe layers 211 are spaced apart from and stacked over one another. In some embodiments, the heat pipe layers 211 can be mounted/secured to a common frame 212, a portion of the reactor vessel 220 (e.g., a wall thereof), and/or other suitable structures within the reactor vessel 220. In other embodiments, the heat pipe layers 211 can be directly stacked on top of one another such that each of the heat pipe layers 211 supports and/or is supported by one or more of the other ones of the heat pipe layers 211.
In the illustrated embodiment, the system 200 further includes a shield or reflector region 214 at least partially surrounding a core region 216. The heat pipes layers 211 can be circular, rectilinear, polygonal, and/or can have other shapes, such that the core region 216 has a corresponding three-dimensional shape (e.g., cylindrical, spherical). In some embodiments, the core region 216 is separated from the reflector region 214 by a core barrier 215, such as a metal wall. The core region 216 can include one or more fuel sources, such as fissile material, for heating the heat pipes layers 211. The reflector region 214 can include one or more materials configured to contain/reflect products generated by burning the fuel in the core region 216 during operation of the system 200. For example, the reflector region 214 can include a liquid or solid material configured to reflect neutrons and/or other fission products radially inward toward the core region 216. In some embodiments, the reflector region 214 can entirely surround the core region 216. In other embodiments, the reflector region 214 may only partially surround the core region 216. In some embodiments, the core region 216 can include a control material 217, such as a moderator and/or coolant. The control material 217 can at least partially surround the heat pipe layers 211 in the core region 216 and can transfer heat therebetween.
In the illustrated embodiment, the system 200 further includes at least one heat exchanger 230 (e.g., a steam generator) positioned around the heat pipe layers 211. The heat pipe layers 211 can extend from the core region 216 and at least partially into the reflector region 214, and are thermally coupled to the heat exchanger 230. In some embodiments, the heat exchanger 230 can be positioned outside of or partially within the reflector region 214. The heat pipe layers 211 provide a heat transfer path from the core region 216 to the heat exchanger 230. For example, the heat pipe layers 211 can each include an array of heat pipes that provide a heat transfer path from the core region 216 to the heat exchanger 230. When the system 200 operates, the fuel in the core region 216 can heat and vaporize a fluid within the heat pipes in the heat pipe layers 211, and the fluid can carry the heat to the heat exchanger 230.
In some embodiments, the heat exchanger 230 can be similar to the steam generator 130 of
In some embodiments, the nuclear reactor systems 100 and/or 200 can include some features that are at least generally similar in structure and function, or identical in structure and function, to any of the nuclear reactor systems described in (i) U.S. patent application Ser. No. 17/071,838, titled “HEAT PIPE NETWORKS FOR HEAT REMOVAL, SUCH AS HEAT REMOVAL FROM NUCLEAR REACTORS, AND ASSOCIATED SYSTEMS AND METHODS,” and filed Oct. 15, 2020, (ii) U.S. patent application Ser. No. 17/071,795, titled “NUCLEAR REACTORS HAVING LIQUID METAL ALLOY FUELS AND/OR MODERATORS,” and filed Oct. 15, 2020, and/or (iii) U.S. patent application Ser. No. 17/404,607, titled “THERMAL POWER CONVERSION SYSTEMS INCLUDING HEAT PIPES AND PHOTOVOLTAIC CELLS,” and filed Aug. 17, 2021, each of which is incorporated herein by reference in its entirety.
Referring to
Referring first to
The substrate 471 can be a separate structure from the wire 472 that is subsequently removed, or can be a portion of the structure being fabricated by the system 470, such as a previously formed/deposited layer of the wire 472 (e.g., a lower layer where the structure is additively manufactured in the longitudinal direction). The thermal energy source 474 and/or the wire 472 can be moved relative to the substrate 471—and/or the substrate 471 can be moved relative to the thermal energy source 474 and/or the wire 472—according to a predefined geometry of the structure to be fabricated to additively build-up the structure. That is, the system 470 can deposit layers of the melted wire 472 in a stack-wise fashion to manufacture the structure. In some embodiments, the system 470 can be configured to supply a gas (e.g., an inert gas) toward the wire 472 to control various parameters of the manufacturing process. In some embodiments, the system can be one of any of the metal 3D printers manufactured by AddiTec Inc. of Las Vegas Nev.
Referring to
At block 362, the method 360 can include directing the beam of thermal energy 475 toward the wire 472 from the thermal energy source 474 to heat and melt the wire 472 while moving the wire 472 relative to the thermal energy source 474 and/or moving the thermal energy source 474 relative to the wire 472. For example, the thermal energy source 474 can sequentially heat and melt the wire 472 as the feed mechanism 476 advances the wire 472 past the beam of thermal energy 475—thereby sequentially forming a weld pool 473 along the wire 472. In some embodiments, the wire 472 can be preheated.
At block 363, the method 360 can include depositing the melted wire 472 (e.g., the weld pool 473) on the substrate 471 according to the desired geometry of the structure to be fabricated. For example, the thermal energy source 474 and the wire 472 can be moved relative to the substrate 471 to selectively deposit a pattern (e.g., a layer) of the melted wire 472 corresponding to a shape/geometry of the desired structure.
At block 364, the method 360 can include cooling the melted wire 472 (e.g., the weld pool 473) such that an oxide of the ODS material remains substantially dispersed (e.g., in solution) within a metal matrix of the ODS material. The weld pool 473 cools and solidifies to form a portion 477 of the structure to be fabricated. In some aspects of the present technology, the cooling of the melted wire 472 can preserve the microstructures of the ODS material, thereby preserving the material properties of the ODS material including, for example, a good creep resistance, wear-resistance, and/or corrosion resistance at elevated temperatures.
More specifically, with continued reference to
Accordingly, the method 360 allows for the fabrication of structures having complex geometries while still preserving the advantageous material properties of the ODS material.
Referring to
In some embodiments, the first channels 584 can be heat pipes that include/define one or more wicks (not shown) and that contain a working fluid (not shown) therein. The working fluid can be a two-phase (e.g., liquid and vapor phase) material such as, for example, lithium, sodium, and/or potassium. The wicks can help move the working fluid against a pressure differential in the first channels 584. In some embodiments, as described in detail above with respect to
Referring to
In other embodiments, the method 360 and the system 470 can be used to fabricate other structures having complex geometries other than the structure 580. Indeed, one of ordinary skill in the art will understand that the method 360 and the system 470 can be used to fabricate structures having many geometries, including one or more of the components of the nuclear reactor systems 100 and/or 200 described in detail with respect to
The following examples are illustrative of several embodiments of the present technology:
The above detailed description of embodiments of the present technology are not intended to be exhaustive or to limit the technology to the precise forms disclosed above. Although specific embodiments of, and examples for, the technology are described above for illustrative purposes, various equivalent modifications are possible within the scope of the technology as those skilled in the relevant art will recognize. For example, although steps are presented in a given order, other embodiments may perform steps in a different order. The various embodiments described herein may also be combined to provide further embodiments.
From the foregoing, it will be appreciated that specific embodiments of the technology have been described herein for purposes of illustration, but well-known structures and functions have not been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments of the technology. Where the context permits, singular or plural terms may also include the plural or singular term, respectively.
As used herein, the phrase “and/or” as in “A and/or B” refers to A alone, B alone, and A and B. To the extent any materials incorporated herein by reference conflict with the present disclosure, the present disclosure controls. Additionally, the term “comprising” is used throughout to mean including at least the recited feature(s) such that any greater number of the same feature and/or additional types of other features are not precluded. It will also be appreciated that specific embodiments have been described herein for purposes of illustration, but that various modifications may be made without deviating from the technology. Further, while advantages associated with some embodiments of the technology have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the technology. Accordingly, the disclosure and associated technology can encompass other embodiments not expressly shown or described herein.
This application claims the benefit of U.S. Provisional Patent Application No. 63/080,571, filed Sep. 18, 2020, and titled “OXIDE DISPERSION STRENGTHENED (ODS) MATERIAL FABRICATION WITH WIRE USING DIRECTED ENERGY DEPOSITION (DED) LASER PRINTING, AND ASSOCIATED SYSTEMS AND DEVICES,” which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63080571 | Sep 2020 | US |
