Patent Description:
<CIT> discloses a modular nuclear reactor comprises a central portion comprising a plurality of structures, each comprising a fuel surrounded by an outer cladding, the fuel defining an annular space at a center portion of the fuel, a heat pipe disposed in the annular space, and an inner cladding between the fuel material and the heat pipe; a side reflector is disposed around the central portion.

<NPL>), discloses a micro heat pipe-cooled (HPR) power source comprising a <NUM> kWe lithium HPR power source, employing uranium nitride fuel with <NUM>% enrichment and a lithium heat pipe.

<CIT> discloses a composite moderator medium for nuclear reactor systems that includes a low moderating material (which includes a moderating matrix of silicon carbide or magnesium oxide) and a high moderating material with a higher neutron slowing down power that is dispersed within the moderating matrix and includes beryllium, boron, or a compound thereof.

The following summary is provided to facilitate an understanding of some of the innovative features unique to the aspects disclosed herein, and is not intended to be a full description. A full appreciation of the various aspects can be gained by taking the entire specification.

In various aspects, a nuclear reactor core is disclosed. The core includes a plurality of interchangeable components configured to effect a performance parameter of the core and a plurality of configurable unit cells formed of a core block material. The plurality of configurable unit cells include a standard unit cell including a plurality of first channels defined within the core block material, wherein each channel of the first plurality of channels is configured to engage an interchangeable component of the plurality of interchangeable components in an operating configuration. The plurality of configurable unit cells also includes a reactivity control cell including a plurality of second channels defined within the core block material, wherein each channel of the second plurality of channels is configured to engage an interchangeable component of the plurality of interchangeable components in the operating configuration, and wherein at least one channel of the second plurality of channels is configured to engage a reactivity control rod. The plurality of interchangeable components and the plurality of configurable unit cells are arranged in a plurality of rows, and wherein at least one row of the plurality of rows overlaps an adjacent row of the plurality of rows such that unit cells of the at least one row and the adjacent row are offset from one another.

Various features of the aspects described herein are set forth with particularity in the appended claims. The various aspects, however, both as to organization and methods of operation, together with advantages thereof, may be understood in accordance with the following description taken in conjunction with the accompanying drawings as follows:.

Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate various aspects of the invention, in one form, and such exemplifications are not to be construed as limiting the scope of the invention in any manner, the invention being defined by the claims.

Numerous specific details are set forth to provide a thorough understanding of the overall structure, function, manufacture, and use of the aspects as described in the disclosure and illustrated in the accompanying drawings. Well-known operations, components, and elements have not been described in detail so as not to obscure the aspects described in the specification. The reader will understand that the aspects described and illustrated herein are non-limiting examples, and thus it can be appreciated that the specific structural and functional details disclosed herein may be representative and illustrative. Variations and changes thereto may be made without departing from the scope of the claims. Furthermore, it is to be understood that such terms as "forward", "rearward", "left", "right", "upwardly", "downwardly", and the like are words of convenience and are not to be construed as limiting terms.

In the following description, like reference characters designate like or corresponding parts throughout the several views of the drawings.

Before explaining various aspects of the articulated manipulator in detail, it should be noted that the illustrative examples are not limited in application or use to the details of construction and arrangement of parts illustrated in the accompanying drawings and description. The illustrative examples may be implemented or incorporated in other aspects, variations, and modifications, and may be practiced or carried out in various ways. Further, unless otherwise indicated, the terms and expressions employed herein have been chosen for the purpose of describing the illustrative examples for the convenience of the reader and are not for the purpose of limitation thereof. Also, it will be appreciated that one or more of the following-described aspects, expressions of aspects, and/or examples, can be combined with any one or more of the other following-described aspects, expressions of aspects, and/or examples.

The present disclosure is directed to devices, systems, and methods to adjust the output of a reactor core. Nuclear reactors are typically manufactured to produce a specific power output for the intended application. Aside from application specific power requirements, the design and production of a nuclear reactor must also comply with a wide variety of internal and/or governmental safety regulations. For example, nuclear reactors must be designed and manufactured in compliance with a number of different criteria, such as: (i) the ability to accommodate a number of different fuels and/or moderators (e.g. graphite, Beryllium Oxide, Yttrium Hydride, Zirconium Hydride); (ii) the ability to be thermo-mechanically self-sufficient during a failure; (iii) the ability to support available manufacturing capabilities; (iv) the ability to integrate with existing core components (e.g. radial reflector); and (v) the ability to be scalable for use with both transportable and stationary mobile reactors. Conventional nuclear reactors are large and therefore limits the number of applications. However, both size constraints and limited applications made it is easier for manufacturers to converge on a small number of conventional designs that could be commercialized in compliance with the applicable requirements and/or regulations.

As nuclear reactors decrease in size they increase in versatility. New nuclear reactors, including micro-reactors, can be effectively implemented in a growing number of emerging and unprecedented applications. However, the reliability of a nuclear reactor's design and performance-as well as its compliance with applicable requirements and/or regulations-is more important than ever. For example, as nuclear reactors become more versatile, they become more prevalent. No single reactor design is suitable for the expanded number of applications. It is commercially impractical to create a new design for each new application. For example, infinite development of new reactor designs can implicate increased costs and risks associated with production and operation. In other words "one size" nuclear reactor does not fit all. Accordingly, there is a need for improved devices, systems, and methods to adjust the output of a reactor core design, while retaining compliance with applicable requirements and/or regulations. Such devices, systems, and methods would enable the reactor to be easily modified for each new application, while preserving the stability of the reactor's manufacture and operation.

Referring now to <FIG>, a perspective view of a core <NUM> that can be modified to adjust the output of a nuclear reactor is depicted in accordance with at least one non-limiting aspect of the present disclosure. According to the non-limiting aspect of <FIG>, the core <NUM> includes a plurality of unit cells <NUM>, which collectively form a hexagonal core plate. Each unit cell <NUM> can be configured to accommodate a heat pipe and fuel in any configuration (e.g. stacks and/or rods), which can collectively generate nuclear power and manage thermal energy throughout the core <NUM>. According to some non-limiting embodiments, one or more unit cells <NUM> can further include a moderator configuration, which can slow down neutrons emitted from the fuel rod configuration. As depicted in the non-limiting aspect of <FIG>, the unit cells <NUM> can be arranged such that the core <NUM> includes an overall hexagonal geometry, However, in other non-limiting aspects, the unit cells <NUM> can be arranged such that the core <NUM> includes any of a number of different geometrical configurations, depending on intended application and/or user preference.

In further reference to <FIG>, the core <NUM> can further include a plurality of reactivity control cells <NUM>. Each cell <NUM> can be configured to accommodate a reactivity control rod configuration, which can collectively work to control the fission occurring within the core <NUM> and therefore, prevent the core <NUM> from achieving a critical temperature in the event of a reactor and/or power failure or criticality accident. According to various non-limiting aspects, the amount of fission can be reduced or completely eliminated within the core <NUM>, the latter of which can shut the core down. The reactivity control rods contemplated by the present disclosure can include a neutron absorbing material and be configured to be inserted into the reactivity control cells <NUM> to slow and/or stop the nuclear reactions in the case of an emergency. The reactivity control configuration of the core <NUM> of <FIG> represents a valuable feature of the modern micro-reactors, which are transportable and have a broader range of commercial applications. Accordingly, the emergence of micro-reactor can increase the prevalence of nuclear technology, making safety a higher priority.

According to the non-limiting aspect of <FIG>, the core <NUM> can further include a reflector <NUM> shield. For example, the reflector <NUM> can include one or more plates composed of a thick, neutron-shielding material and configured to substantially surround the core <NUM>. The reflector <NUM> can further include a plurality of control drums <NUM> configured to house a neutron absorptive material. In the event of a reactor and/or power failure, the control drums <NUM> can turn inward towards the core <NUM> such that the absorptive material can mitigate radiation and control the temperature of the core <NUM>. According to some non-limiting aspects, the reflector <NUM> can additionally and/or alternatively include a gamma shield configured to further mitigate radiation in the event of a failure. As depicted in the non-limiting aspect of <FIG>, the reflector <NUM> can be arranged in a circular configuration that surrounds the hexagonally arranged plurality of unit cells <NUM>. However, in other non-limiting aspects, the reflector <NUM> can be arranged to form any of a number of different geometrical configurations about the plurality of unit cells <NUM>, depending on intended application and/or user preference.

Still referring to <FIG>, the reflector <NUM> can be sectioned to ensure that a gap exists between the unit cells <NUM> and the reflector <NUM> as a means of controlling and promoting a desired amount of heat transfer. For example, the reflector <NUM> can be formed from a plurality of modular plates integrated to create the aforementioned gap. However in other non-limiting aspects, the reflector <NUM> can be integrally formed. Additionally, the reflector <NUM> can be further configured to extend along an axial direction D1, which defines a length L of the core <NUM>. The plurality of unit cells <NUM> can also be configured to span the length L of the core <NUM>. Since the unit cells are configured to accommodate fuel, the magnitude of the length L of the core <NUM> can correspond to a desired output of the nuclear reactor. Additionally and/or alternatively, the increased versatility of micro-reactors mean the core <NUM> must be configurable for a wide variety of applications, many of which might have size and/or weight constraints. Therefore, the design of core <NUM> allows for the length L to be specifically configurable to accommodate for the output, size, and/or weight requirements of the nuclear reactor.

Referring now to <FIG>, a top view of the core design of <FIG> is depicted in accordance with at least one non-limiting aspect of the present disclosure. <FIG> illustrates how the plurality of unit cells <NUM> and the plurality of reactivity control cells <NUM> can be particularly arranged to establish the hexagonal configuration of the non-limiting aspect of the core <NUM>. It is also evident that each unit cell <NUM> of the plurality of unit cells <NUM> and each reactivity control cell <NUM> of the plurality of reactivity control cells <NUM> include a hexagonal configuration as well. However, it shall be appreciated that the hexagonal configuration is exclusively depicted for illustrative purposes. Accordingly, the present disclosure contemplates other non-limiting aspects in which the unit cells <NUM> include any number of geometrical configurations (e.g. square, circular, triangular, rectangular, pentagonal, octagonal) and arranged such that the core <NUM> can include any number of geometrical configurations.

In further reference of <FIG>, the plurality of unit cells <NUM> and the plurality of reactivity control cells <NUM> can be arranged along a radial direction D2, thereby defining a radial dimension R of the core <NUM>. Specifically, the non-limiting aspect of <FIG> depicts a core <NUM> with <NUM> unit cells <NUM>. However, the present disclosure contemplates other non-limiting aspects wherein the core <NUM> includes any number of unit cells <NUM>. In fact, the ability to easily add or subtract the number of unit cells <NUM> to the core <NUM> without dramatically altering its design allow the core <NUM> to be easily scaled depending on the intended application and/or user preference. As such, the output of the core <NUM> design can also be easily adjusted for a multitude of applications and requirements. For example, a user can change the radial dimension of the core <NUM> by adding or subtracting unit cells <NUM> to the core <NUM> design in the radial direction. Since the unit cells are configured to accommodate fuel including radioactive isotopes, increasing or decreasing the magnitude of the radial dimension R can alter the output of the core <NUM>. Accordingly, the radial dimension R of the core <NUM> can correspond to a desired output of the nuclear reactor depending on the intended application and/or user preference. Additionally and/or alternatively, the radial dimension R of the core <NUM> can be specifically configured to comply with a multitude of size and/or weight requirements, which can vary by application.

It shall be appreciated that the term "radial", as used in the present disclosure, describes any direction extending from the center of the core <NUM> when viewed from the top. Accordingly, the use of the term "radial" shall not be limited to circular or circular-like configurations and shall not be construed to imply that the core <NUM> of <FIG> and <FIG> is limited to circular, or circular-like, configurations. For example, the present disclosure contemplates non-limiting aspects in which the core <NUM> includes a rectangular configuration. According to such aspects, the core <NUM> can include one or more radial dimensions of varying lengths.

Still referring to <FIG>, the plurality of unit cells <NUM> and the plurality of reactivity control cells <NUM> can be integrally formed from a solid block of material (e.g. graphite). Thus, the internal features of each of the unit cells <NUM>, such as heat pipe channels, fuel rod channels, moderator channels, and/or the like, can be bored out of-and integrally formed from-the solid block of material. However, according to other non-limiting aspects, each unit cell <NUM> of the plurality of unit cells <NUM> and each reactivity control cell <NUM> of the plurality of reactivity control cells <NUM> can be modularly formed and integrated into the core block to promote the adjustability of the core design. Regardless, the core <NUM> can be easily manufactured to include any number of unit cells <NUM> and/or reactivity control cells <NUM>. This can allow the core <NUM> design to be easily scalable. For example, altering the number of unit cells <NUM> and reactivity control cells <NUM> allows the user to alter the radial dimension R and length L (<FIG>) of the core <NUM>, thereby altering its output and flexibility for applications with unique output and/or space constraints. However, the core <NUM> design essentially remains the same, which allows for predictability in production and performance regardless of the difference in output and size. These features also reduce the amount of non-recurring engineering required to design for a new application and facilitates manufacturing consistency and the standardization of parts. Although the core <NUM> of <FIG> and <FIG> can be scaled as a means of adjusting its output, the scaling should further consider the power rating of the implemented heat pipes, the appropriate number of reactivity control rods required for the adjusted output, and the effectiveness of the control drums.

In further reference to <FIG>, each of the cells <NUM> can be configured to be self-sufficient. As used in this disclosure, "self-sufficient" shall be construed as the ability of each unit cell <NUM> to independently dissipate heat generated by the fuel oriented within the unit cell <NUM> via heat rods. However, as a safety measure, the unit cells <NUM> are specifically arranged such that the gap G between any two adjacent unit cells <NUM> is less than or equal to <NUM> millimeters. As such, in the event one or more heat pipes fail within any given unit cell <NUM>, the adjacent unit cells <NUM> can be positioned close enough to unit cell <NUM> with the failed heat pipe such that it will transfer the excess heat away from the core <NUM>. Thus, the unit cells <NUM> can be configured to ensure that the core <NUM> can operate at an acceptable temperature, even when a unit cell is no longer self-sufficient due to heat pipe failure.

Additionally, the unit cells <NUM> of <FIG> can be geometrically configured and oriented relative to one another in a triangular pattern, which includes a predetermined pitch calculated to achieve a desired output. For example, the core <NUM> of <FIG> can include a pitch that is greater or equal to fifteen centimeters and less than or equal to twenty centimeters. However, the present disclosure contemplates other non-limiting aspects including any number of different pitches based on any number of desired outputs, as required by the intended application and/or user preference. Hence, the plurality of unit cells <NUM> can include a variety of geometrical variables, which can be attenuated to further adjust the output of the core <NUM>. In fact, it is the particular geometry and the relative locations of unit cells <NUM>, as well as the configuration and geometry of the reflector <NUM>, that can be carefully selected to adjust the output of the core <NUM> to satisfy the demand of a particular application while complying with additional requirements.

Referring now to <FIG>, a top view of a unit cell <NUM> of the core <NUM> of <FIG> and <FIG> is depicted in accordance with at least one non-limiting aspect of the present disclosure. According to the non-limiting aspect of <FIG>, the unit cell <NUM> can include a plurality of fuel channels <NUM> configured to accommodate fuel of the core <NUM> and a plurality of heat pipe channels <NUM> configured to accommodate a heat pipe of the core <NUM>. Specifically, the unit cell <NUM> of <FIG> includes twenty-four fuel channels <NUM> and seven heat pipe channels <NUM>. However, it shall be appreciated that the unit cell <NUM> can include any number of fuel channels <NUM> and heat pipe channels <NUM> to optimize the generation of nuclear energy and enhance the efficiency by which thermal energy is removed from the core <NUM>. As previously discussed, each unit cell <NUM> is configured to be self-sufficient. Accordingly, each heat pipe channel <NUM> can be surrounded by several fuel channels <NUM> of the core, such that thermal energy generated by fuel inserted within the fuel channels <NUM> can be effectively transferred away from the core <NUM>. For example, the fuel can include neutron emitting materials (e.g. Uranium Oxide, Tri-structural isotropic Particle Fuels with Uranium Nitride or Uranium Oxycarbide kernels).

According to other non-limiting aspects, the unit cell <NUM> of <FIG> can further include a moderator channel configured to accommodate a moderator (e.g. a hydride-based moderator, BeO, etc.) of the core <NUM>, wherein the moderator can be configured to retard and suppress the propagation of neutrons emitted by fuel inserted in the plurality of fuel channels <NUM>. Alternatively and/or additionally, the unit cell <NUM> can include additional features, configured to accommodate other instrumentation of the core <NUM>.

In further reference to <FIG>, the plurality of fuel rod channels <NUM> can be configured to have a first diameter D1 and the plurality of heat pipe channels <NUM> can be configured to have a second diameter D2. According to some non-limiting embodiments, the first diameter D1 and the second diameter D2 are selected to assist the unit cell <NUM> in being self-sufficient, such that the heat pipes inserted into the heat pipe channels <NUM> have ability to transfer heat away from the core <NUM>. Similar to the gaps G between unit cells <NUM>, the first diameter D1 of the fuel channels <NUM> and the second diameter D2 of the heat pipe channels <NUM> can be configured such that a desired gap exists between fuel and the internal walls of a fuel channel <NUM>, as well as between a heat pipe and the internal walls of a heat pipe channel <NUM>, when are properly inserted into the unit cell <NUM>. Again, such gaps can be geometrically configured to optimize energy generations and heat transfer throughout the unit cells <NUM> and throughout the core <NUM> as a whole. Although the non-limiting aspect of <FIG> includes channels <NUM>, <NUM> with a circular configuration, it shall be appreciated that the present disclosure contemplates other non-limiting aspects wherein the channels <NUM>, <NUM> with any number of geometric configurations to optimize heat transfer for the intended application and user preference. Accordingly, the term "diameter", as used by the present disclosure, shall not include any dimension that extends away from a center point of the channel <NUM>, <NUM>. As such, it shall be appreciated that the term "diameter" is not intended to limit the channels <NUM>, <NUM> to a circular configuration.

Still referring to <FIG>, the unit cell <NUM> can also include features configured to accommodate a neutron absorbing materials that can slow the nuclear reactions occurring in the fuel rod channels <NUM> of the unit cells <NUM>. Accordingly, the power distribution and radial power peaking of the unit cells <NUM>-and consequentially, the core <NUM> itself-can be further adjusted via the influence of neutron absorbers. According to some non-limiting aspects, the core <NUM> can be designed for an application that does not impose a strict transportation requirement on the core <NUM>. Alternatively and/or additionally, the core <NUM> can use of a high-density fuel. According to such aspects, the axial power peaking factor and axial power distribution of the unit cells <NUM> and core <NUM> can be otherwise managed by varying the fuel enrichment level within the fuel channels <NUM> of the unit cells <NUM>.

Referring now to <FIG>, a perspective view of the unit cell of <FIG> is depicted in accordance with at least one non-limiting aspect of the present disclosure. According to the non-limiting aspect of <FIG>, a plurality of unit cells <NUM> are configured to extend along at least a portion of the length L of the core <NUM>. For example, each unit cell <NUM> of the plurality of unit cells <NUM> can be modularly formed and integrated into the core block to promote the adjustability of the core design, which represents one aspect of adjustability offered by the design of core <NUM>. This can assist the core <NUM> in compliance with the output and/or size requirements associated with the intended application. In other non-limiting aspects contemplated by the present disclosure, the unit cells <NUM> can be integrally formed along at least a portion of the length of the core <NUM>, but similarly configured to achieve the desired output.

Similarly, the reflector <NUM> configuration depicted in <FIG> includes a plurality of reflectors <NUM> including control drums <NUM>, wherein the reflectors <NUM> are configured to extend along at least a portion of the length L of the core <NUM>, similar to the configuration previously depicted and discussed in reference to <FIG>. Of course, according to some non-limiting aspects, the reflectors too can be integrally formed. Again, the reflectors can be specifically configured to create advantageous gaps to promote and enhance heat transfer throughout the core <NUM>.

Additionally and/or alternatively, according to some non-limiting aspects, it can be advantageous for a row of unit cells <NUM> to overlap with an adjacent row of unit cells <NUM>. For example, according to the non-limiting aspect of <FIG>, a side view of the unit cell of <FIG> is depicted in accordance with at least one non-limiting aspect of the present disclosure. As can be seen in <FIG>, the unit cells 102a, 102b are offset relative to one another. Such overlapping can enhance energy production and/or heat transfer throughout the core <NUM> and provide the user with one more geometric variable to attenuate to optimize core <NUM> performance without dramatically altering core <NUM> design.

Referring now to <FIG>, a perspective view of the core <NUM> of <FIG> is depicted in accordance with at least one non-limiting aspect of the present disclosure. According to the non-limiting aspect of <FIG>, the core <NUM> can be assembled to include fuel <NUM>, heat pipes <NUM>, and reactivity control rods <NUM> dispositioned throughout the plurality of unit cells <NUM> and reactivity control cells <NUM>. Specifically, the fuel <NUM> can be dispositioned throughout the fuel channels <NUM> (<FIG>) of one or more unit cells <NUM>, the heat pipes <NUM> can be dispositioned throughout the heat pipe channels <NUM> (<FIG>) of one or more unit cells <NUM>, and the reactivity control rods <NUM> can be dispositioned through a reactivity control channel (not shown) of one or more reactivity control cells <NUM>. According to some non-limiting aspects, the fuel <NUM> and heat pipes <NUM> are configured to extend the predetermined length L of the core <NUM>. In other non-limiting aspects, the heat pipes <NUM> are configured to extend an additional length L' beyond the predetermined length L of the core, to facilitate downstream ex-core connections and/or equipment (e.g. power systems, condensers, structural supports). This design allows the core <NUM> to be customized for any intended application and/or user preference, which enables it to be versatile in response to customer needs. However, none of these alterations can dramatically affect the underlying nuclear physics and/or manufacturability of the core <NUM> design, which preserves reliability and predictability in core <NUM> production and operation. In other words, the assembled core <NUM> design of <FIG> allows the fuel <NUM> and heat pipes <NUM> to be specifically configured to accommodate for any specific power requirement and/or structural configuration without having to reinvent the basic core <NUM> design and assume the inherent development risks.

In further reference to <FIG>, the reflector <NUM> can further include a plurality of control drums <NUM> configured to house a neutron absorbing and reflective materials. In the event of a reactor and/or power failure or reactor shut down, the control drums <NUM> can turn inward towards the core <NUM> such that the absorbing material can shut down the core <NUM>. According to non-limiting aspect of <FIG>, the reflector <NUM> can further include a gamma shield <NUM> configured to substantially surround a neutron shield, the core <NUM>, and its internal components <NUM>, <NUM>, <NUM>, <NUM>, <NUM> to further mitigate radiation.

Still referring to <FIG>, the core <NUM> can further include a plurality of reactivity control rods <NUM> configured to be dispositioned through one or more reactivity control cell <NUM> of the plurality of reactivity control cells <NUM>. For example, the reactivity control cells <NUM> can include a reactivity control rod channel similar to the fuel channels <NUM> and/or heat pipe channels <NUM>, but specifically configured to accommodate a reactivity control rod <NUM>. As previously discussed, each reactivity control rod <NUM> can include a neutron absorbing material configured to slow and/or stop the nuclear reactions within the core <NUM> in the case of an emergency. The reactivity control rods <NUM> can collectively work to prevent the core <NUM> from achieving a critical temperature in the event of a reactor and/or power failure. Accordingly, the emergence of micro-reactor can increase the prevalence of nuclear technology, making safety a higher priority.

Referring now to <FIG>, a sectioned perspective view of the core <NUM> of <FIG> is depicted in accordance with at least one non-limiting aspect of the present disclosure. According to the non-limiting aspect of <FIG>, the core <NUM> including the reflector <NUM> can be configured to be positioned within an external shroud <NUM>, which can imbue the core <NUM> with additional structural, shielding, and heat transfer properties depending on the intended application and/or user preference. Notably, <FIG> illustrates how the unit cells <NUM> and reactivity control cells <NUM> can be arranged relative to one another to form a plurality of fuel channels <NUM> (<FIG>), heat pipe channels <NUM> (<FIG>), and reactivity control rod channels (not shown) that traverse through a block of the core <NUM>. The sectioned view depicts the fuel <NUM>, heat pipes <NUM>, and reactivity control rods <NUM> dispositioned within the channels <NUM>, <NUM>, thereby forming the functional crux of the core <NUM>. Accordingly, it shall be appreciated that the number of unit cells <NUM> and/or reactivity control cells <NUM> can be varied to adjust the output and/or geometrical configuration of the core <NUM> without significantly altering its design.

It shall be appreciated that, for at least the foregoing reasons, the core <NUM> design disclosed herein includes an adjustable output with a high manufacturability readiness level. In other words, existing manufacturing techniques can be used to make one unit cell or a cluster of unit cells, the reflector, and/or the overall assembly disclosed herein. Accordingly, the core <NUM> can be assembled for in-process control of individual core components (e.g. unit-cells, reflector segments) and can include components that are easy to replace and/or modify as needed. These features facilitate the scalability of the core <NUM> and are especially valuable when compared to monolithic core configurations.

Referring now to <FIG>, several stress distributions of the core <NUM> of <FIG> are depicted in accordance with at least one-aspect of the present disclosure. For example, <FIG> illustrate a temperature distributions of at least a portion of the core of <FIG>. As previously discussed, the unit cells <NUM> can be arranged such that no greater than a predetermined gap G (<FIG>) exists between any two adjacent cells <NUM>. The gap G (<FIG>) enables excess heat to be dissipated by neighboring heat pipes of neighboring unit cells <NUM> in the event of a heat pipe failure. For example, in <FIG>, a typical temperature distribution is depicted without heat removal degradation. However, in <FIG>, a heat pipe has failed, as is represented by the temperature concentration at point A. Because the neighboring unit cells <NUM> are positioned no more than a predetermined gap G from the unit cell <NUM> with the failed heat pipe, the excess heat can be dissipated by neighboring heat pipes. This is evident in the dissipation of the thermal gradient depicted in <FIG>. In other words, the core <NUM> can be specifically configured such that neighboring unit cells <NUM> can help to remove heat in case of the heat pipe failure.

<FIG> illustrate a comparison of stress distributions in at least a portion of the core of <FIG> with stress distributions in a conventional, monolithic core, in accordance with at least one non-limiting aspect of the present disclosure. As is evident from <FIG>, the equivalent stress in the improved core <NUM> configuration of <FIG> is reduced when compared to stresses in a monolithic core. Although the stress distribution pattern is similar, the magnitude of the stresses experienced is significantly less. <FIG> illustrate simulated temperature and stress distributions for a maximum expected power level of the core of <FIG>, in accordance with at least one non-limiting aspect of the present disclosure. Accordingly, <FIG> illustrate that the overall stresses experienced by the core <NUM> and its components are below the conventional limits for operating conditions of a nuclear reactor. Accordingly, <FIG> illustrate that, even as the output of the core is adjusted, the core <NUM> design can facilitate sufficient thermal management capabilities such that the stresses experienced by the core <NUM> remain in compliance with other customer requirements and/or internal and governmental regulations.

Referring now to <FIG>, a method <NUM> of adjusting the power output of a core of a nuclear reactor is depicted in accordance with at least one non-limiting aspect of the present disclosure. According to the non-limiting aspect of <FIG>, the method <NUM> can include adjusting the power output of a core that includes a plurality of unit cells. Each unit cell of the plurality of unit cells is configured to accommodate a fuel configured to generate energy. Furthermore, each unit cell of the plurality of unit cells is configured to accommodate a heat pipe configured to transfer thermal energy away from the core. An initial number of unit cells in the plurality of unit cells corresponds to an initial power output of the core. For example, the initial power output could be a standardized output of the core product line, which takes into account an average output desired by customers of the product line. This can minimize the amount of adjustment required and thus, reduce the amount of development and risk required to adjust the output of the core.

In further reference of <FIG>, the method <NUM> can include determining an amount of fuel based on a desired power output of the core <NUM>. For example, the desired power output of the core can correspond to an intended application of the nuclear reactor. If the nuclear reactor is going to be powering more equipment than the standard, initial product can provide, then the desired power output would be higher than the initial power output. Alternatively, the application could require less power but also afford the core less space or real estate. Accordingly, the output and thus, footprint of the core should be reduced. Next, the method includes determining a number of heat pipes based on a predetermined requirement of the core <NUM>. For example, the nuclear reactor might have to comply with contractual, internal, or governmental thermal requirements or factors of safety. This could affect the number of heat pipes required to maintain the desired output in compliance with the requirements imposed on the nuclear reactor.

Still referring to <FIG>, the method <NUM> further includes determining a number of unit cells based on the determined amount of fuel and the determined number of heat pipes <NUM>. In other words, the method calls for the optimization of power and compliance requirements. This optimization is then integrated into the modular core design. Subsequently, the method includes mechanically altering the plurality of unit cells such that the initial number of unit cells becomes the determined number of unit cells <NUM>. Accordingly, the scalable core is modified to conform with the configuration determined based on the desired power output and compliance to requirements.

Referring now to <FIG>, a top view of a unit cell 1100a including a configurable layout is depicted in accordance with at least one non-limiting aspect of the present disclosure. According to the non-limiting aspect of <FIG>, the unit cell 1100a can include a plurality of channels <NUM>, <NUM> defined within a core block material <NUM>. For example, the unit cell 1100a can include a plurality of fuel channels <NUM> and/or a plurality of heat pipe channels <NUM>. The channels <NUM>, <NUM> of the unit cell 1100a can be configured to accommodate various interchangeable components required by a nuclear reactor core and can be arranged in a configurable pattern to achieve criticality and/or a desired output of the nuclear reactor. According to some non-limiting aspects, each channel <NUM>, <NUM> can be simultaneously configured to accommodate any of the interchangeable components, including fuel sources and/or heat pipes. As such, the unit cell 1100a of <FIG> can be an integral component of a plurality of integrated unit cells 1100a forming a core of a nuclear reactor that relies on fuel and heat pipes to generate electricity and remove the resulting thermal energy. According to the non-limiting aspect of <FIG>, the layout of the unit cell 1100a can be configurable-that is, the number and/or location of channels <NUM>, <NUM> can be rearranged to alter the performance of the core-as long as the unit cell 1100a ultimately remains in compliance with nuclear and/or physical and thermal requirements.

According to the non-limiting aspect of <FIG>, the core block material <NUM> of the unit cell 1100a can be specifically configured to supplement and/or replace moderators typically required by other core designs. For example, the core block material <NUM> can be specifically selected to include properties that can decrease the speed of neutrons emitted by fuel sources installed within the fuel channels <NUM> of the unit cell 1100a. As such, the core block material <NUM> itself can control the rate of fission occurring within fuel channel <NUM> of the unit cell 1100a. Accordingly, the unit cell 1100a can reduce and/or eliminate the need to incorporate additional moderators that can otherwise diminish the unit cell's 1100a capacity to accommodate fuel and/or heat pipes. Without the need for moderator channels, the unit cell 1100a can make more efficient use of its layout and ultimately decrease the size of the core while improving the output performance of the nuclear reactor. It shall also be appreciated that the core block material <NUM> can be further configured to include a number of desirable physical properties (e.g. elastic modulus, thermal conductivity, strength, web-thickness, and/or thermal expansion) to withstand the nuclear, structural, and/or thermal stresses of the unit cell 1100a,.

In further reference to <FIG>, the unit cell 1100a can further include a plurality of fuel channels <NUM> configured to accommodate a variety of fuel types (e.g. Uranium Dioxide, Tri-structural isotropic Particle Fuels with Uranium Nitride or Uranium Oxicarbide kernels). The unit cell 1100a layout of <FIG> can be specifically configured for a particular fuel type, or the unit cell 1100a layout can be universally configured to accommodate any number of fuel types in a standard configuration. Additionally, the unit cell 1100a can be accommodate a variety of fuel configurations based on a desired fuel utilization and/or moderation requirement. According to the non-limiting aspect in which the core block material <NUM> of the unit cell 1100a can be specifically configured to supplement and/or replace moderators, the fuel <NUM> can also be configured to accommodate a variety of fuel sources and/or secondary moderators to optimize reactor performance variables and ensure compliance with a variety of requirements and/or regulations, which vary by application. Accordingly, the single unit cell 1100a layout of <FIG> can be configured and reconfigured as desired.

The configurable cell block 1100a layout of <FIG> provides numerous advantages, such as applicability to various reactor designs that require varying moderator configurations. For example, the unit cell 1100a layout of <FIG> can include a Uranium Nitride and/or a Tri-structural Isotropic Particle fuel source installed within a subset of the plurality of fuel channels <NUM>. According to such aspects, the unit cell 1100a might comply with a nuclear reactor transportation requirement but suffer in terms of fuel utilization. Accordingly, the user may decide to insert secondary moderators (e.g. hydride-based material , Beryllium Oxide) into a subset of the plurality of fuel channels <NUM> to attenuate reactor performance and thus, improve fuel utilization.

According to another non-limiting aspect, the unit cell 1100a can include a Uranium Dioxide and/or a Uranium Nitride fuel source within a subset of the plurality of fuel channels <NUM> to optimize fuel utilization, but will likely require the use of a secondary moderator in other fuel channels <NUM> to comply with reactor transportation requirements. None of the foregoing examples are intended to be limiting but rather, are exclusively presented to illustrate how the unit cell 1100a layout of <FIG> can be configurable to optimize reactor performance for compliance to a number of different requirements and/or regulations. Accordingly, a single unit cell layout 1100a can be applicable and specifically configured for a wide array of nuclear reactor applications (e.g. mobile reactors, transportable reactors, stationary reactors). Streamlining the production of unit cells <NUM>a, <NUM>b to include a single, configurable layout-such as those depicted in <FIG>-can promote manufacturing readiness and facilitate the use of existing manufacturing techniques.

Referring now to <FIG>, another unit cell including a configurable layout is depicted in accordance with at least one non-limiting aspect of the present disclosure. The unit cell <NUM>b is similarly configured to the unit cell 1100a of <FIG>. However, according to the non-limiting aspect of <FIG>, the unit cell <NUM>b can further include one or more reactivity control channels <NUM> configured to accommodate a reactivity control rod, which can work to prevent the core <NUM> from achieving a critical temperature in the event of a reactor and/or power failure. For example, the reactivity control channels <NUM> of the unit cell <NUM>b of <FIG> can accommodate reactivity control rods that include a neutron absorbing material configured to slow and/or stop the nuclear reactions occurring within the fuel channels <NUM> in the case of an emergency.

In further reference to <FIG>, the reactivity control channel <NUM> can be larger than the fuel channels <NUM> and heat pipe channels <NUM> of the unit cell <NUM><NUM>b. However, the present disclosure contemplates other non-limiting aspects wherein the reactivity control channels <NUM> can include a variety of different sizes and/or geometric configurations relative to the fuel channels <NUM> and heat pipe channels <NUM> of the unit cell <NUM>b. Additionally and/or alternatively, the unit cell <NUM>b of <FIG> can be configured to be coupled to the unit cell <NUM>a of <FIG>, thereby establishing a core with a reactivity control configuration in further compliance with application specific requirements and/or regulations. Accordingly, the unit cells 1100a, <NUM>b of <FIG> can collectively provide an additional benefit to modern micro-reactors. As previously discussed, such micro-reactors are compact and thus, increasing the prevalence of nuclear technology. Therefore, safety remains a high priority when designing the core of a nuclear reactor. The configurable layout of unit cell <NUM>b can allows for the core design to be customized and thus, can assist in mitigating the risks that are inherent to the use nuclear technology.

Although the unit cells <NUM>a, <NUM>b of <FIG> can include a hexagonal configuration, it shall be appreciated that the hexagonal configuration is exclusively depicted for illustrative purposes. Accordingly, the present disclosure contemplates other non-limiting aspects in which the unit cells 1100a, <NUM>b can include any number of geometrical configurations (e.g. square, circular, triangular, rectangular, pentagonal, octagonal) and thus, can be arranged to form cores of many different geometrical configurations. Additionally and/or alternatively, the channels <NUM>, <NUM>, <NUM> can include any geometrical configuration and are not intended to be limited to the circular geometries depicted in <FIG>. It shall be appreciated that the modular and reconfigurable features of unit cells 1100a, <NUM>b can be equally applied to channels of varying geometrical cross-sections (e.g. square, circular, triangular, rectangular, pentagonal, octagonal).

It shall be appreciated that the layout of the unit cells <NUM>a, <NUM>b can be specifically configured based on the intended application and/or user preference. This enables any core constructed from the unit cells 1100a ,<NUM>b to be flexibly designed to accommodate the versatility expected of modern, micro-reactors. For example, the arrangement of channels <NUM>, <NUM>, <NUM> can include a predetermined pitch P between channels. The pitch P can be specifically configured based on the particular fuel type intended for the core. For example, the pitch P of <FIG> can include a dimensional magnitude greater than or equal to <NUM> millimeters and less than or equal to <NUM> millimeters. However, the present disclosure contemplates other non-limiting aspects including pitches of varying dimensional magnitudes based on any other nuclear and/or thermal characteristic of the core, depending on the intended application and/or user preference.

Likewise, each channel <NUM>, <NUM>, <NUM> of the unit cells <NUM>a, <NUM>b of <FIG> can include a predetermined channel diameter DC which can be designed to establish a desired gap to accommodate fuel, heat pipe, and/or reactivity control rod, respectfully. Accordingly, the channel diameter DC can be specifically configured for a desired amount of nuclear generation, heat removal, and/or reactivity control capability, depending on intended application and/or user presence. It shall be appreciated that, as the channel diameter DC is adjusted to accommodate varying fuel sources (e.g. rods, stacks, pellets, and/or compacts), subsequent re-adjustments to the pitch P may be needed, especially if the channel diameter DC is increased to accommodate broader fuel sources to achieve higher power ratings. Additionally and/or alternatively, each channel <NUM>, <NUM>, <NUM> of the unit cells <NUM>a, <NUM>b can be arranged such that a predetermined radial gap GR exists between channels <NUM>, <NUM>, <NUM>. The radial gap GR can be selected to ensure a certain proximity between channels <NUM>, <NUM>, <NUM> is maintained. Accordingly, the channels <NUM>, <NUM>, <NUM> are arranged to collectively achieve a performance expectation of the unit cell 1100a, <NUM>b. For example, if a first heat pipe fails, a heat pipe in a neighboring channel can accommodate for the failure by transferring excess heat away from the unit cell <NUM>a, <NUM>b and thus, the core itself. This ensures that the unit cell 1100a, <NUM>b can comply with applicable performance requirements and/or safety regulations in the event of a failure.

In other words, the channels <NUM>, <NUM>, <NUM> of the unit cells <NUM>a, <NUM>b of <FIG> can be easily configured to accommodate any nuclear, thermal, and/or safety design constraints. The typical radial gap between elements of the design will vary depending on the interface type, fuel and heat pipe dimensions, required heat generation rate, and cover (filling) gas used. However, modifying any of the aforementioned dimensions (e.g. pitch P, channel diameter DC, radial gap GR, web-tllickness) to alter the geometrical configuration of the unit cell <NUM>a, <NUM>b, channels <NUM>, <NUM>, <NUM> will not disrupt the aforementioned manufacturing readiness, standards, or limits.

Referring now to <FIG>, a top view of another unit cell <NUM> including a configurable layout is depicted in varying configurations in accordance with at least one non-limiting aspect of the present disclosure. According to the non-limiting aspect of <FIG>, a baseline unit cell 1200a configuration is depicted, wherein fuel <NUM> is positioned in channels surrounding a central heat pipe <NUM> in a hexagonal configuration. According to the non-limiting aspect of <FIG>, the baseline unit cell 1200a configuration does not include secondary moderators installed within any of the channels. Alternatively, the baseline unit cell 1200a configuration can include a core block material <NUM> that serves as the moderator (e.g. graphite).

Referring now to <FIG>, a second unit cell <NUM>b configuration is depicted in accordance with at least one non-limiting aspect of the present disclosure. According to the non-limiting aspect of <FIG>, the unit cell <NUM>b can include Beryllium-based moderators <NUM> (e.g. Beryllium Carbide, Beryllium Oxide) interposed between the channels that include the fuel <NUM>, which are the same as the channels depicted in <FIG>. Referring now to <FIG>, a third unit cell <NUM>c configuration is depicted in accordance with at least one non-limiting aspect of the present disclosure. Similar to the aspect of <FIG>, the unit cell <NUM>c configuration of <FIG> can include moderators <NUM> interposed between the channels that house fuel sources <NUM>. However, according to the non-limiting aspect of <FIG>, the moderators can include a hydride-based material (e.g. Yttrium Hydride, Zirconium Hydride).

Collectively, <FIG> illustrate how a single unit cell <NUM>, or the unit cells <NUM>a, <NUM>b of <FIG>and <FIG>, can include configurable layouts that can alter the output and/or performance of the core of a nuclear reactor in compliance with a wide variety of application-specific requirements and/or regulations, while preserving a desirable manufacturing readiness level. Although the non-limiting unit cell <NUM>a, <NUM>b, <NUM>c configurations illustrate the use of different moderators <NUM>, <NUM>, <NUM> throughout the core of the nuclear reactor, it shall be appreciated that the unit cell <NUM>a, <NUM>b, <NUM>c configurations can apply similar modular principles to effect any number of core parameters, including the use of different fuel sources and/or reactivity control rods.

Referring now to <FIG>, a method <NUM> of configuring a unit cell of a core of a nuclear reactor is depicted in accordance with at least one non-limiting aspect of the present disclosure. According to the non-limiting aspect of <FIG>, the method <NUM> can include determining an operating condition of the core, wherein the operating condition corresponds to an intended application and/or user preference of the nuclear reactor <NUM>. This step is indicative of the increased versatility offered by modern nuclear reactors. Next, the method <NUM> determines a performance parameter of the unit cell that comprises an aspect of the operating condition <NUM>. For example, the specific application of the reactor might necessitate a particular power output, or moderator capability of the core. Accordingly, the user can dissect the operating condition into one or more performance parameters that can influence the design of the core and, more specifically, the design of the unit cell. Next, the method <NUM> includes the selection of an interchangeable component that corresponds to the performance parameter <NUM>. Based on the selected performance parameter, the user might choose a fuel source of a particular type or composition, or a reactivity control rod, or a heat pipe for inclusion in the unit cell layout. Finally, the method includes the installation of the selected interchangeable component into a channel of the plurality of channels <NUM>. The method <NUM> can be repeated until the channels of the unit cell are populated with the required interchangeable components such that the core can achieve the operating condition and be effective in the intended application.

The present invention has been described with reference to various exemplary and illustrative aspects. The aspects described herein are understood as providing illustrative features of varying detail of various aspects of the disclosed invention; and therefore, unless otherwise specified, it is to be understood that, to the extent possible, one or more features, elements, components, constituents, ingredients, structures, modules, and/or aspects of the disclosed aspects may be combined, separated, interchanged, and/or rearranged with or relative to one or more other features, elements, components, constituents, ingredients, structures, modules, and/or aspects of the disclosed aspects without departing from the scope of the disclosed invention. Accordingly, it will be recognized by persons having ordinary skill in the art that various substitutions, modifications or combinations of any of the exemplary aspects may be made without departing from the scope of the invention. In addition, persons skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the various aspects of the invention described herein upon review of this specification. Thus, the invention is not limited by the description of the various aspects, but rather by the claims.

Those skilled in the art will recognize that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to claims containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should typically be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations.

In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to "at least one of A, B, or C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that typically a disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms unless context dictates otherwise. For example, the phrase "A or B" will be typically understood to include the possibilities of "A" or "B" or "A and B.

It is worthy to note that any reference to "one aspect," "an aspect," "an exemplification," "one exemplification," and the like means that a particular feature, structure, or characteristic described in connection with the aspect is included in at least one aspect. Thus, appearances of the phrases "in one aspect," "in an aspect," "in an exemplification," and "in one exemplification" in various places throughout the specification are not necessarily all referring to the same aspect. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner in one or more aspects.

As used herein, the singular form of "a", "an", and "the" include the plural references unless the context clearly dictates otherwise.

Directional phrases used herein, such as, for example and without limitation, top, bottom, left, right, lower, upper, front, back, and variations thereof, shall relate to the orientation of the elements shown in the accompanying drawing and are not limiting upon the claims unless otherwise expressly stated.

The terms "about" or "approximately" as used in the present disclosure, unless otherwise specified, means an acceptable error for a particular value as determined by one of ordinary skill in the art, which depends in part on how the value is measured or determined. In certain aspects, the term "about" or "approximately" means within <NUM>, <NUM>, <NUM>, or <NUM> standard deviations. In certain aspects, the term "about" or "approximately" means within <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, <NUM>%, or <NUM>% of a given value or range.

In this specification, unless otherwise indicated, all numerical parameters are to be understood as being prefaced and modified in all instances by the term "about," in which the numerical parameters possess the inherent variability characteristic of the underlying measurement techniques used to determine the numerical value of the parameter. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter described herein should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

Claim 1:
A nuclear reactor core comprising:
a plurality of interchangeable components, wherein each interchangeable component of the plurality of interchangeable components is configured to affect a performance parameter of the core (<NUM>); and
a plurality of configurable unit cells, wherein each configurable unit cell of the plurality of configurable unit cells is formed of a core block material, and wherein the plurality of configurable unit cells comprise:
a standard unit cell (<NUM>) comprising a first plurality of channels defined within the core block material, wherein each channel of the first plurality of channels is configured to engage an interchangeable component of the plurality of interchangeable components in an operating configuration; and
a reactivity control cell (<NUM>) comprising a second plurality of channels defined within the core block material, wherein each channel of the second plurality of channels is configured to engage an interchangeable component of the plurality of interchangeable components in the operating configuration, wherein at least one channel of the second plurality of channels is configured to engage a reactivity control rod;
characterized in that
the plurality of interchangeable components and the plurality of configurable unit cells (<NUM>, <NUM>) are arranged in a plurality of rows, wherein at least one row (102a) of the plurality of rows overlaps an adjacent row (102b) of the plurality of rows such that unit cells of the at least one row and the adjacent row are offset from one another.