Nuclear heat plants with load-following generation.

Abstract

To provide a system for generating, storing and converting heat energy, which is safer, more flexible and efficient.SOLUTION: A system includes: a nuclear reactor with a heat power output; and a power generating system being in thermal communication with the nuclear reactor and having a heat power input. In the system, the heat power input is larger than the heat power output.SELECTED DRAWING: Figure 10

Description

Detailed Description of the Invention

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application No. 62 / 833,623, filed April 12, 2019, and U.S. Provisional Application No. 62 / 929,003, filed October 31, 2019, both entitled "NUCLEAR THERMAL PLANT WITH LOAD-FOLLOWING POWER GENERATION," the disclosures of which are incorporated by reference in their entireties.

[0002] 〔background〕 The field of the disclosure relates to nuclear reactors, and more particularly to nuclear reactors for producing heat with improved safety and load-following capabilities.

[0003] Conventional methods and systems for generating electrical power from nuclear reactors require the reactor to undergo significant planning, construction, and regulatory approval of a nuclear island before the reactor can be started. The reactor is connected to a power cycle for converting nuclear thermal energy into electrical power, typically via a steam turbine using water as the working fluid. While nuclear reactors operating in this manner have been around for decades, the typical configuration suffers from several drawbacks.

[0004] For example, nuclear islands, including reactor areas, fuel handling systems, and energy conversion systems, typically operate at high temperatures and pressures, which require large containment structures. Furthermore, structures located on nuclear islands must also be inspected and given nuclear licenses by regulatory authorities in order to operate, which is a lengthy and costly endeavor.

[0005] Furthermore, nuclear reactors are subject to errors in the rest of the plant, such that malfunctioning equipment can cause the nuclear plant to automatically shut down. Finally, nuclear power plants are not designed for rapid changes in power output and therefore cannot efficiently follow load demands from the power grid.

[0006] While nuclear power plants offer many significant advantages over other forms of power generation, it is desirable to provide improvements that result in safer, more flexible, and more efficient systems for generating, storing, and converting thermal energy, as well as other features that will become apparent from the following description.

[0007] Summary of the Invention According to certain embodiments, a nuclear power plant can be reconfigured, relocated, and operated as a nuclear heat plant, which provides numerous advantages. For example, a nuclear power plant can be reconfigured and operated to provide thermal energy, which can be transported to an off-site thermal storage system. The thermal storage system can then be coupled to an energy conversion plant that converts the thermal energy into industrial heat, electricity, or some other useful purpose. There are many advantages that can be realized by decoupling the nuclear reactor from the rest of the plant, including the energy conversion system.

[0008] For example, regulatory licensing can be accomplished much more efficiently if less equipment is installed on a nuclear island. In some reactors, the coolant is provided by a liquid metal, such as sodium. When sodium encounters water, the resulting reaction is exothermic and energetic, and safety systems must be in place to inhibit this reaction and contain it if it occurs. By locating the steam plant remotely from the reactor, the reactor is isolated from any water-containing systems that may typically be used in conjunction with a nuclear power plant.

[0009] Additionally, multiple nuclear heat plants can be coupled to a shared thermal storage system, which provides benefits in terms of cost and construction time, ease of maintenance as one or more reactors can be shut down without affecting the entire nuclear heat plant, and allows the nuclear heat plant to effectively supply more energy during periods of high demand than if it were directly coupled to an energy conversion system.

[0010] The following discussion provides concepts that offer advancements in the economics of sodium reactor plants, as well as reactor plants using other fuels, coolants, and technologies. These advances could result from reimagining the technology to reduce cost and schedule uncertainties, or from expanding revenue streams, such as by providing both power and heat to consumers. In addition to economic benefits, ensuring the ability to solve policy issues (such as grid reliability, proliferation resistance, exportability, and on-site availability) can enable benefit realization.

[0011] BRIEF DESCRIPTION OF THE DRAWINGS A better understanding of the features, advantages, and principles of the present disclosure will be obtained by reference to the following detailed description that sets forth exemplary embodiments and the accompanying drawings.

[0012] Figure 1 shows a typical nuclear power plant.

[0013] FIG. 2 illustrates a nuclear heat plant decoupled from a power plant, according to an embodiment.

[0014] FIG. 3 illustrates a nuclear heat plant coupled to a thermal storage plant, according to an embodiment.

[0015] FIG. 4 illustrates a nuclear heat plant coupled to a remote thermal storage plant with optional auxiliary thermal storage, according to an embodiment.

[0016] FIG. 5 illustrates a nuclear heat plant coupled to a remote thermal storage system coupled to an external load, according to an embodiment.

[0017] FIG. 6 shows an exemplary industrial heating application and the temperatures required.

[0018] FIG. 7 illustrates an energy system in which multiple heat sources share a common thermal storage and energy conversion system, according to an embodiment.

[0019] FIG. 8 illustrates an energy system in which multiple heat sources share a common thermal storage and energy conversion system with an auxiliary power system, according to an embodiment.

[0020] FIG. 9 illustrates a nuclear heat plant coupled to a remote heat storage system coupled to an external load and auxiliary heat utilization, according to an embodiment.

[0021] FIG. 10 illustrates a hybrid energy system in which multiple forms of thermal energy generators are coupled to a common thermal storage system and a common power conversion system, according to an embodiment.

[0022] FIG. 11 illustrates an energy system in which the nuclear block is decoupled from the power block by an integrated energy storage block, according to an embodiment.

[0023] Detailed Description The following detailed description provides a better understanding of the features and advantages of the present invention described in the present invention, in accordance with the embodiments disclosed herein. Although the detailed description includes many specific embodiments, these are provided by way of example only and should not be construed as limiting the scope of the invention disclosed herein.

[0024] While nuclear power costs are important and deserve attention, the revenue and policy aspects of nuclear power merit equal focus. Nuclear power costs are a key metric in describing commercial attractiveness while entering a highly regulated, commoditized market for baseload power generation. Finding approaches that reduce regulatory burdens and expand commercial market opportunities is key to progressive economic change that increases revenue for modest cost increases. Enabling technological solutions to policy problems also has strategic value that is difficult to capture when considering construction costs overnight. Leveraging currently undervalued attributes such as zero CO2 emissions, combined with the ability to integrate with an increasingly dynamic grid, will become more valuable in the coming decades.

[0025] In addition to the operational cost challenges of load following with nuclear energy, baseload generation does not have the ability to profitably follow electricity because the price of electricity fluctuates daily, as do "peaker" plants (e.g., power plants that can only operate when there is high or peak demand). To improve the competitiveness of nuclear power in a changing energy environment, technology and process innovations are needed to enable nuclear power plants to operate at full capacity and access market arbitrage opportunities in addition to full-power generation. During periods when electricity prices fall below the cost of production from intermittent renewable energy sources, nuclear power plants require alternative means of production to solely meet load-following electricity demand. This fundamentally necessitates an understanding of the competitive advantages of nuclear power plants compared to intermittent renewable energy sources. These competitive advantages lead to the desire and opportunity for co-location with other industrial processes to achieve economies of concentration in energy production and manufacturing processes.

[0026] One of the characteristics of nuclear power compared to wind, solar, and other renewables is concentrated shaft power, which precedes electricity generation or thermal output. Leveraging these differences can provide a competitive advantage during low-cost energy production, either by more efficiently storing energy or creating another saleable product. Many power generation facilities rely on the steam Rankine cycle to convert thermal energy to electricity. While the conversion of shaft power to electricity in a rotating generator is highly efficient (98–99%), the conversion of electricity to shaft power is slightly less efficient (~95%). Additional losses occur in stepping up voltage for transmission, transmitting electricity over transmission lines, and stepping down voltage for local consumption. While the exact losses from transmission to consumption are location- and distance-specific, the overall estimated loss from nuclear plant generation to on-site electricity consumption is estimated at 2–4% in this example. Combined efficiency losses indicate an 8–11% efficiency gain for direct shaft power compared to generation versus shaft power at another location. As a result, a potential competitive advantage exists between power generation and direct shaft power work with a sufficiently capable clutch and gear system. The clutch and gear system can fully or partially convert shaft power to non-power work. The challenge is start / stop applications up to gigawatt scale and the mass flow rates of each product to support those enormous workloads.

[0027] One such example is enabling nuclear power plants to operate at full capacity during periods of low electricity prices (and therefore low power demand) by using compressed air energy storage (CAES) or liquefied air energy storage (LAES) to provide shaft power for liquefying air in addition to supplying baseload power demand. The cryogenic liquefied air stored at atmospheric pressure can later be boiled with nuclear waste heat to drive turbines for power generation. CAES and LAES are estimated to scale to GW-hour scale storage, representing a significant capability for power management. The stored liquefied air can then drive turbines during peak power prices, removing nuclear from baseload pricing alone. Given the scalability of CAES and LAES technologies and the technological maturity of large cryogenic storage tanks, there is an opportunity to combine centralized shaft power for nuclear cryogenic cooling with waste heat to boil liquefied air and drive turbines. This combination of capabilities is more effective than the electrically driven pump requirements and "thermal storage" needs of currently proposed CAES and LAES technologies, giving the joint technology a competitive advantage compared to either technology alone. With proper development, this technology could be retrofitted to the current US nuclear fleet, which produces 99 GW of electricity.

[0028] While the most promising use of CAES and LAES is for energy production, more selective distillation of liquefied compressed air can also produce high-quality gas streams as a saleable product. One example would be selling a pure oxygen stream from thermal distillation for medical applications or power generation to companies that want to simplify carbon capture by eliminating the NOx and SOX issues associated with simply burning natural gas and oxygen. This opens up the possibility of coexisting natural gas power plants with CAES nuclear plants to simplify carbon sequestration. The remaining distillate gases could be fed for their low-temperature, specific gas value, or consumed in wind turbines to generate electricity, for example.

[0029] Another similar application of shaft power in the United States is the liquefied natural gas (LNG) export market, where demand continues to grow, reaching approximately 8.9 billion cubic feet per day by 2019. Currently, up to 10% of the feed gas for liquefaction is consumed in the process. Using a more conservative estimate of 4100 kJ / kg liquefaction, approximately 230 GWh of energy is required annually to support the current liquefaction process. Nuclear power plants can play an important role in increasing LNG exports to other parts of the world through direct compression or a combination of cold water CAES on one side of a heat exchanger and CAES energy storage using natural gas on the other side. In this combined system, natural gas is liquefied for storage or export, and compressed air is boiled to turn an electric turbine. In either case, air and natural gas can be brought into the power plant, easily processed, and relatively amenable to "start-stop" operation to accommodate load following.

[0030] Another fluid pumping example is ultra-pumped hydro / aquifer renewal as a rational start / stop application. Assuming market signals develop over the next decade to warrant large-scale pumping efforts and associated pipelines, the efficiency gains using direct shaft power for aquifer renewal could be as much as 7 quads per year (i.e., 1 quad is 10 quads). 15 BTU, or 1.055 x 10 18 The potential for water reclamation could be as much as 1000 joules (1000 sq ft) or more. Presumably, water reclamation efforts would reduce the pumping effort required, but likely would not eliminate the need for replacement water. Furthermore, this pumping effort would also serve as a huge "pumping" capacity that could be reversed along the pipeline to supplement intermittent power sources and replenish regional aquifers.

[0031] As mentioned above, centralized shaft power is only one of the key characteristics of nuclear power compared to solar, wind, and other renewable power options. Industrial processes such as those producing refined oil, coke, steel, chemicals, and cement require both energy and a specific temperature. This minimum temperature requirement for chemical processes to occur is a key differentiator for which primary energy source is best. While primary heat consumption is specific to a single market, temperature requirements for a given process are universal. While processes have a spectrum of temperature requirements, the primary temperatures of interest appear to be between 100 and 250°C, with steam and hot water production, refining (petrochemical) processes in the 250–550°C range, and high-temperature processes for cement, steel, and glass production exceeding 1000°C. Looking at the energy market as a whole, petroleum refining consumes more than six quads per year, and forest products consume just over three quads per year.

[0032] Fossil fuels currently meet both the scale and temperature of energy demands. In a decarbonized energy world, the challenge is to find the best way to replace the utility and versatility of fossil fuels. Wind, solar, and hydropower generate significant amounts of energy but do not generate significant amounts of quality heat. These energy sources must undergo other energy conversions to create higher-quality process heat. Pricing for these energy sources must include additional processes such as hydrogen production through resistance heaters or blast furnaces. Additional energy storage requirements may exist to achieve high capacity factors to operate industrial equipment 24 hours a day or to accept "lost opportunities" in low-capacity plants.

[0033] Nuclear power plants have competed on price by competing with heat, not electricity, based on $ / kWe converted to the required temperature versus $ / MMBTU. One of the most obvious starting points of competition is direct steam generation and consumption. Forest products consume 1.3 quads of steam per year, equivalent to over 45 GWth of a nuclear power plant operating 24 hours a day simply for process steam. In forest products production, part of the process generates waste products such as black liquor (e.g., waste from the Kraft process, which digests pulp to paper pulp and removes lignin, hemicellulose, and other extractives from wood to remove cellulose fiber), biomass, and other residual fuels, which are burned for process heat to produce steam. The remainder of the required fuel is currently supplemented by coal or natural gas. Using nuclear power for steam would free up 1,330 TBtu (1.3 quads) of primary energy for other high-temperature uses, such as oil refining and cement applications. By utilizing nuclear thermal energy to provide high-quality process heat for forestry, recovered forest product energy, combined with reserve energy, could supply the energy requirements for both cement and glass manufacturing in the United States (less than 1 quad combined). Combustion of forest products is considered carbon-neutral, thus allowing nuclear substitution of steam generation to directly support high-temperature processes. While there is great flexibility in fuel sources for cement manufacturing, technological innovation will be necessary to ensure that forest fuel products can be transported and used for other primary thermal applications. Similar to forest products, chemical manufacturing as a whole consumes 1.2 quads of steam that could be directly replaced with steam generated from nuclear power generation. However, this energy displacement does not completely liberate renewable fuel sources; it simply reduces the amount of natural gas and coal required to drive the process, and even in this case, renewable energy is also burned to support its conversion to products.

[0034] Another use of nuclear steam is for nuclear plants to produce steam for hydrogen electrolysis during periods when intermittent power sources produce cheap electricity, combined with electricity when the intermittent sources are off. As steam temperature increases, less power is required to drive electrolysis. However, improving power efficiency at higher temperatures may not be economically attractive in a world where peak intermittent generation drives electricity costs "cheap to the meter." If the cost of the electrolyzer could be inexpensively integrated into the steam bypass pipeline, nuclear reactors could easily shift to electrolysis, partially or entirely, during periods of cheap electricity. This would allow nuclear plants to compete for heat production during periods of low electricity prices and electricity during periods of high electricity prices. The resulting hydrogen production should be considered not only as an energy storage mechanism but also as a source of industrial heat demand above 1000°C, such as for cement, iron, steel, and glass.

[0035] With advanced reactors with higher outlet temperatures, more direct industrial process opportunities become available. For example, higher reactor outlet temperatures could be used as preheaters for other industrial processes or as the primary heat source for chemical processes. In petroleum refining, there are significant energy demands for hydrocarbon distillation and cracking, requiring over six quads of energy. Sodium-cooled reactors could be the primary heat source for numerous low-temperature cracking processes, and reactor heat could be "warmed up" to the required peak refinery temperatures using electrical heating or small amounts of fossil fuels. Much of the technical challenge in this case is establishing refinery technology to accept temperature and energy inputs other than oil, electricity, and steam, while minimizing the number of heat exchangers and losses during heat exchange. One example would be the substitution of salt / oil heat exchangers for traditional combustion boxes for high-temperature cracking. Other types of advanced reactors, such as molten salt reactors, could be used, for example, to directly generate the required high-temperature industrial process heat.

[0036] Thermal storage opportunities also exist to decouple nuclear heat plant heat production from heat utilization. It has been proposed to use a nuclear heat plant's primary coolant, such as phase-change salt, to heat large thermal storage reservoirs and pump them into large tanks. These large tanks of heated salt could then be used later to generate electricity, such as through a steam Rankine cycle, or to provide application-based process heat. By decoupling heat generation from its direct utilization, the thermal storage reservoirs provide a flexible means of "load following" electricity generation by operating at full power and filling the high-temperature brine tanks, but generating electricity at times of greater value, such as during peak demand or more traditional baseload energy generation. This approach also allows the nuclear power plant to operate like a peaker plant for price arbitrage opportunities while still operating at full power. Additional cost savings exist if the nuclear power plant and primary coolant / salt heat exchangers and salt storage facilities can be separated as not critical to the reactor's safety, thereby allowing construction and equipment regulations for electricity generation to be similar to those for non-nuclear power plants. This allows for typical commercial security protocols, operation and maintenance costs ("O&M"), and quality standards that can justify any heat exchangers or heat losses by pumping the hot salt out of the secure area of ​​the nuclear power plant. Essentially, the power system for a nuclear power plant (with associated maintenance work) could be built in a non-NQA1 environment and obtain a commercially competitive build from an existing solar salt power company.

[0037] Higher-temperature reactors, such as sodium-cooled, molten salt, and high-temperature gas reactors, can also participate in hydrogen production using processes different from wind and photovoltaic power, in addition to the steam-electrolysis discussed earlier. One example of a high-temperature process is the copper-chlorine cycle. This cycle uses process heat at 400–500 °C to produce hydrogen and oxygen gas. The final step in the cycle uses ambient-temperature electrolysis to recycle all chemicals except water, which is converted to gas. This process represents an interesting opportunity to “supply-follow” the cheap electricity generated during periods of peak wind and solar power. By operating a higher-temperature nuclear thermal plant nonstop to produce hydrogen and oxygen gas, the plant equipment and O&M costs are justified while the copper-chlorine reactants for electrolysis are charged into the tanks. When electricity becomes cheap, ambient-temperature electrolysis is used to convert the tanks back into the appropriate chemical precursors, starting the cycle again. This process is similar in spirit to charging hot salt into a salt tank for later use, but is more specifically tailored to the final chemical product. While this example does not necessarily advocate the copper-chlorine cycle, the idea of ​​supply-following electricity is a different approach than storing energy to follow demand. This process also allows most of the nuclear plant equipment used to produce hydrogen to be used, with only some tanks and electrolyzers idle during normal operation.

[0038] These features and benefits, as well as many others, can be realized by relocating nuclear power plants, allowing the co-location of nuclear heat plants with industrial and chemical heat uses, allowing the footprint of the NQA1 certified area to be reduced, and allowing load-following capability while operating the reactor at full power.

[0039] Referring to FIG. 1, a typical nuclear power plant 100 is shown. The layout of the nuclear power plant 100 includes two main sections: a nuclear island and a turbine island. The nuclear island has a reactor area 102 at its center, which houses the nuclear reactor. A fuel handling area 104 is adjacent to the reactor area, and both buildings are typically located within a containment area 106. The containment area 106 can include a containment enclosure structure, which can be reinforced steel, concrete, or lead, or a combination of materials that form the enclosing structure that contains the reactor. Its design and function is to contain any escaping radioactive vapors or gases, and is often designed to contain escaping gases at pressures of 550 kPa or greater. The containment structure is designed as a last line of defense to withstand a design basis accident. The cost to build a containment structure is not only directly proportional to the size of the reactor, but is also based on the rest of the plant's systems and components that need to be housed within it. The nuclear island also includes auxiliary components such as pumps, fluid loops, control rooms, and other support components.

[0040] The fuel handling area 104, which may be within the containment region 106, is designed to provide refueling capability at a rate that maintains continuous reactor operation. The fuel handling area 104 also contains subcritical fuel outside the reactor core to prevent damage or contamination of the fuel. The fuel handling area 104 may also include equipment for moving fuel pins and fuel assemblies, such as for reloading fuel into the reactor core.

[0041] Coupled to the reactor area and portions of the nuclear island are steam generators 108. In some cases, the steam generators 108 are located within the containment area 106 and provide superheated steam to steam turbines 110. The steam generators 108 receive thermal power from the reactor and transfer the thermal energy to the steam turbines 110, which convert the steam energy into mechanical energy. In some installations, radioactive water passes through the steam turbines 110 but must be kept within the radiologically controlled areas of the nuclear power plant. The steam turbines 110 are, in turn, mechanically coupled to generators 112, which convert the mechanical energy from the steam turbines 110 into electrical power.

[0042] A fuel pin inspection area 114 may be on-site to perform post-irradiation inspection ("PIE") and analysis. The fuel pin inspection area 114 is often adjacent to the fuel handling area 104 due to sharing of competitive fuel handling equipment. The fuel pin inspection area 114 may further include a hot cell for storing and inspecting irradiated fuel pins.

[0043] As shown in FIG. 1 , the containment area 106 may be required to encompass the reactor region 102 as well as the fuel handling area 104. In some cases, the steam generator 108 building and associated equipment are located outside the containment area 106, but in many cases, they are required to be located within the containment area 106. One or more coolant loops are used to transfer heat from the reactor region 102 via heat exchangers to a cooling fluid, which not only cools the reactor core but also allows heat to be transported from outside the containment area to the steam generator 108 building. Often, the primary coolant loop receives heat from the reactor core via a primary heat exchanger and transfers thermal energy to the secondary coolant loop via a secondary heat exchanger. In many cases, the coolant in the primary coolant loop becomes radioactive. Many currently used nuclear reactors rely on water under high pressure as both a coolant and a neutron moderator. The primary coolant typically undergoes a phase change from liquid to vapor as it absorbs thermal energy from the reactor core and then transfers the thermal energy to the secondary loop.

[0044] The coolant in the secondary loop, which may be water, receives heat from the primary coolant loop and undergoes a phase change from liquid to vapor, which is used to drive the steam generator. This superheated steam is typically under high pressure, which requires that safety measures be in place to contain the high-pressure and high-temperature steam in the event of a failure.

[0045] In some instances, the primary and / or secondary coolant may be another material, such as molten metal. For example, some fast reactors use molten metal, such as liquid sodium, as the coolant. In other instances, molten salt may be used as the coolant. Both molten metal and molten salt have low vapor pressures even at high temperatures and are therefore capable of transferring heat at lower pressures than water can at similar temperatures.

[0046] Nuclear power plant 100 is typically protected by a site boundary 120, which may include a security perimeter such as a tall fence with razor wire. Nuclear power plant 100 and its associated buildings, structures, systems, pipes, etc. may be referred to as the reactor site, which is located within reactor site boundary 120. Additional security measures such as gates across all access points, guards at access points, surveillance cameras, motion detectors, and / or electrified fencing, among other measures, are typically used to protect the reactor site.

[0047] Nuclear power plant 100 is further required to have an emergency planning zone ("EPZ"), which is required to prepare for a serious accident at the nuclear power plant. In many cases, the EPZ encompasses a 10-mile radius from the nuclear power plant 100.

[0048] As shown in FIG. 2 , the reactor region 202 and the fuel handling area 204 are located within a containment area 206 having a containment structure. These two major buildings, along with the control room, constitute a nuclear island. Compared to the typical nuclear power plant shown in FIG. 1 , it can be seen that the steam generators, steam turbines, generators, and fuel pin inspection area are no longer located on the nuclear island. Rather, these components are located away from the nuclear island. The illustrated reactor region 202 is configured as a nuclear thermal plant 200 and is designed and operated to generate heat (as opposed to electricity in a typical nuclear power plant). In the illustrated configuration, a thermal storage system 208 is remote from the nuclear island and receives thermal energy from the nuclear thermal plant 200. Note that the thermal energy generated by the nuclear thermal plant 200 is transported away from the nuclear island, often across a site boundary 210 and even beyond the EPZ.

[0049] One immediate advantage of this configuration is that the thermal storage 208 and power generation 212 facilities are outside the scope of nuclear regulations, which allows the nuclear heat plant 200 to be constructed and licensed much more efficiently than is possible for nuclear power plant installations.

[0050] 2 may be any suitable type of reactor. For example, the reactor may include, but is not limited to, a thermal spectrum reactor, a fast spectrum reactor, a multi-spectrum reactor, a breeder reactor, or a traveling wave reactor. Thermal energy generated by the reactor may be transferred to a thermal storage system using an energy transfer system 214.

[0051] In some embodiments, the reactor may utilize fuel that does not require heavy equipment to handle the fuel, such as for reloading fuel pins or refueling the reactor. Thus, in these embodiments, the fuel handling area 204 may be much smaller than that required to move fuel pins and fuel assemblies in and out of the reactor core. Such reactors may include pool-type reactors or molten salt reactors, among others. One advantage of this type of reactor is that the fuel handling area 204 may be much smaller, and therefore the nuclear island and / or containment area 206 may be smaller than that typically required by reactors utilizing fuel pins and fuel assemblies, which therefore require heavy equipment for their handling and manipulation.

[0052] In some embodiments, the nuclear reactor may include a nuclear reactor having a liquid coolant. For example, the liquid coolant of the nuclear reactor may include, but is not limited to, a liquid metal or salt coolant (e.g., uranium chloride, uranium trichloride, uranium tetrachloride, lithium fluoride, beryllium fluoride, or other chloride or fluoride salts), a liquid metal coolant (e.g., sodium, NaK, other sodium alloys, lead, or lead bismuth), a liquid organic coolant (e.g., diphenyl with diphenyl oxide), or a liquid water coolant.

[0053] In another embodiment, the nuclear reactor may include a nuclear reactor having a pressurized gas coolant, which may include, but is not limited to, pressurized helium gas or pressurized carbon dioxide gas.

[0054] In another embodiment, the nuclear reactor may include a nuclear reactor having a mixed-phase coolant, for example, but not limited to, a gas-liquid mixed-phase material (e.g., steam-liquid water).

[0055] Thermal storage system 208 may include any suitable thermal storage plant, whether now known or later developed. In some embodiments, the thermal storage system may store thermal energy in the range of 500°C or greater. In some examples, the thermal storage system stores energy at 550°C, 600°C, 700°C, 750°C, or greater. In some examples, the thermal storage system 208 is designed to store thermal energy at 1000°C or greater. In some embodiments, the thermal storage system 208 has multiple thermal stores to store thermal energy at different temperatures.

[0056] The thermal storage system 208 is in thermal communication with the nuclear reactor by an energy transfer system 214. The energy transfer system 214 receives thermal energy from a primary heat exchanger associated with the nuclear reactor. For example, the reactor primary coolant passes through the primary heat exchanger, transferring thermal energy from the reactor core to the energy transfer system 214, thus cooling the primary coolant and transferring the thermal energy to the energy transfer system 214. The energy transfer system 214 can be considered a secondary coolant loop designed to receive thermal energy from the primary coolant loop and transport the thermal energy to the thermal storage system 208.

[0057] For example, a first portion of the energy transfer system 214 may be in thermal communication with a portion of the primary coolant loop of the nuclear reactor, and a second portion of the energy transfer system 214 may be in thermal communication with the thermal storage system 208.

[0058] Those skilled in the art will recognize that a combination of heat exchange loops, heat exchangers, and heat pipes may be used in conjunction to provide heat from the reactor to the energy transfer system 214 and to the thermal storage system 208. For example, a primary heat exchanger including multiple heat pipes may be used to thermally couple the primary heat exchange loop of the reactor to the energy transfer system 214. A second heat exchanger, which may include multiple heat pipes, may be used to thermally couple the energy transfer system 214 to the thermal storage system 208. In this manner, thermal energy generated by the reactor may be transferred to the thermal storage system 208. The energy transfer system 214 may utilize a liquid metal, salt, or some other working fluid to facilitate heat transport. Alternatively, the energy transfer system 214 may be in direct thermal communication with the storage medium of the thermal storage system 208, such as where the storage medium may travel from the thermal storage system 208 and enter a first heat exchanger within the reactor vessel.

[0059] The power generation system 212 can be in thermal communication with the thermal storage system 208 downstream of the thermal storage system. The result of this type of configuration is that the nuclear island is decoupled from the power generation system 212. In other words, a failure occurring in equipment associated with the power generation system 212 or the thermal storage system 208 does not immediately affect the reactor. In traditional nuclear reactor systems, a failure of equipment associated with the power generation system 212 would often cause an automatic and immediate shutdown of the reactor core. This is typically provided as a safety feature to avoid problems caused by excess heat generation without sufficient heat transfer capacity to remove the excess heat from the reactor system.

[0060] In some examples, thermal storage system 208 has a thermal energy capacity greater than the thermal power output of the nuclear reactor is designed to output. For example, thermal storage system 208 may be designed to provide 1200 MWth of energy, while the nuclear reactor may be designed and operated to provide 400 MWth of energy. This allows thermal storage system 208 to store excess energy above and beyond that provided by the nuclear reactor and provide this energy to power plant 212 as needed. For example, when the load demand on thermal storage system 208 is lower than the power output of the nuclear reactor, thermal storage system 208 is charged with additional thermal energy. During times of high demand, when the load demand on thermal storage system 208 is greater than the power output of the nuclear reactor, thermal storage system 208 is discharged.

[0061] 2, a power generation plant 212 is coupled to the thermal storage system 208. The power generation system 212 may be any now known or later developed power generation system 212. In one embodiment, the power generation system 212 receives thermal energy from the thermal storage system 208 and converts the thermal energy into electrical power.

[0062] In some cases, the thermal energy may be passed through a steam generator to produce high temperature, high pressure steam that can be used to drive a steam turbine, which in turn drives an electrical generator that converts the mechanical work of the steam turbine into electrical power, which can be supplied to an electrical grid, as is known.

[0063] In another example, the thermal energy from the thermal storage system 208 can be delivered to a solid-state power generator that converts the heat directly into electricity, without the need to generate steam or convert the thermal energy into mechanical work. Such systems are currently under development, and the disclosed embodiments are well suited to be coupled to future power plants that require heat to generate electricity.

[0064] The thermal storage system 208 is in thermal communication with the power generation system 212 via any suitable means. For example, an energy supply system 216 may be provided to supply thermal energy from the thermal storage system 208 to the power generation system 212. For example, the energy supply system 216 may include a fluid loop having a first portion in thermal communication with the thermal storage system 208, such as by a heat exchanger, and a second portion in thermal communication with the power generation system 212, such as by another heat exchanger. The heat exchanger may be any suitable heat exchanger, such as, but not limited to, a shell-and-tube heat exchanger, a double-pipe heat exchanger, a plate heat exchanger, a condenser, an evaporator, a boiler, or a combination of one or more different types of heat exchangers, to name a few.

[0065] The illustrated configuration and application of the thermal storage system 208 allows the nuclear reactor to be isolated from power conversion applications. This provides many advantages. For example, the nuclear reactor is no longer subject to transients from outside the site boundary 210 that would cause the rest of the plant to fail. These types of malfunctions can be handled without having to shut down the reactor. In conventional nuclear power plants, plant transients can lead to reactor failures, which are an economic and safety concern. These transients can be caused by malfunctions in the rest of the plant's systems, such as a malfunctioning component in a steam generator, steam turbine, or some other auxiliary component, causing the reactor to shut down. With the nuclear thermal plant 200, these issues are no longer a concern because the nuclear reactor is isolated from the rest of the plant's systems. Any of the power generation system 212, the thermal storage system 208, or the nuclear reactor system can be safely shut down, such as for maintenance, without affecting the other systems.

[0066] For example, a nuclear reactor system can be shut down and taken offline while the thermal storage system 208 can continue to provide thermal energy to the power generation system 212, which continues to provide electrical power. Similarly, the power generation system 212 can be shut down or operated at a reduced power output while the nuclear reactor system continues to generate thermal energy, essentially charging the thermal storage system 208. In one embodiment, the nuclear reactor system is operated at full capacity, and the thermal energy is transferred to the thermal storage system 208, which is completely independent of the load on the power generation system 212. The load on the power generation system 212 tends to vary throughout the day, week, month, and season, while the nuclear reactor system can operate continuously at full capacity regardless of the load.

[0067] Additionally, in nuclear heat plants utilizing sodium-cooled reactors, relocating the steam generation system to a remote location as described increases safety because there is little or no risk of water from the steam cycle interacting with the sodium used in the reactor.

[0068] In traditional nuclear power plants, the intermediate coolant loop transfers thermal energy from the reactor's primary coolant loop to the steam generators, and because of its proximity to the reactor core, it is exposed to radiation and must be designed to withstand this type of radiation, which degrades materials of construction. For example, certain metals can become embrittled due to radiation hardening, which reduces their toughness and leads to the possibility of brittle fracture. In the described configuration, the intermediate coolant loop is moved away from the reactor (or eliminated entirely), and the intermediate coolant loop can be made of materials that are easier to source and manufacture and therefore cheaper and more readily available.

[0069] As shown, the thermal storage system 208 and the power generation system 212 are outside the site boundary 210 of the nuclear thermal plant 200. Specifically, the nuclear thermal plant 200 is within the site boundary 210, such as a security fence, and all equipment within the site boundary is subject to strict nuclear regulations. If the remaining systems of the plant, such as the thermal storage system 208 and the power generation system 212, are located remotely outside the site boundary 210, these systems are subject to significantly less regulation and are much more efficient to construct, license, and operate. These remaining systems of the plant may even be located outside the EPZ.

[0070] In some embodiments, nuclear thermal plant 200 may include an intrinsically safe reactor, and the EPZ may be sized to coincide with site boundary 210. In other examples, the EPZ may be sized to be within site boundary 210. In either case, locating the remainder of the plant's systems outside of reactor site boundary 210 has numerous advantages in terms of safety, efficiency, and speed of construction and licensing.

[0071] Additionally, in the described configuration, the nuclear heat plant 200 is capable of load following. Load following is the concept of adjusting power output as power demand fluctuates throughout the day. Traditional nuclear power plants typically operate at full power all the time and generally do not vary their output power. In the described configuration, the nuclear heat plant 200 can operate at full power, which may be designed to meet the base load requirements of the power grid. The base load of a power grid is the minimum level of demand over a period of time. This demand can be met by continuous power plants, dispatchable generation (e.g., for on-demand power systems), a collection of smaller intermittent energy sources, or a combination of energy sources. The remainder of the demand, which fluctuates throughout the day, can be met by dispatchable generation that can be quickly turned up or down, such as load-following power plants, peaking power plants, or energy storage.

[0072] Thermal energy output from the nuclear heat plant 200 is stored in the thermal storage system 208 and supplied as needed to the power generation system 212. In other words, the nuclear heat plant 200 can charge the thermal storage at a substantially constant rate, and the thermal storage system 208 can supply the thermal energy to the power generation system 212 to generate electricity that follows the electrical load demand from the power grid. Thus, the nuclear heat plant 200 can not only meet base load requirements, but also provide load-following capability while operating continuously at or near full power.

[0073] Additionally, the thermal storage system can be larger than the size that the nuclear heat plant 200 is configured to supply, allowing the nuclear heat plant 200 to "charge" the thermal storage system during periods of off-peak electrical demand. In many load-following power plants, the plant operates during the day and evening and operates in direct response to changing power demand. The power plant can shut down in the evening or at night when demand is lower and then start up again as demand increases during the day. In the described configuration, the nuclear heat plant 200 can operate continuously, and the generated thermal energy can be stored until needed to generate electricity or for some other purpose. In some examples, the nuclear heat plant 200 can generate less thermal energy than is needed to meet peak load demand, but the thermal storage can be charged during off-peak use times so that the overall energy output from the nuclear heat plant 200 can supply base load and peak load demand over time.

[0074] In other examples, the nuclear heat plant 200 may produce more energy than is needed to meet base load demand. For example, the nuclear heat plant 200 may produce enough thermal energy to be used to meet base load demand, plus excess thermal energy to meet peak load demand, and may also provide additional thermal energy for other industrial purposes.

[0075] 3, a nuclear heat plant 200 is shown that includes a heat-producing nuclear reactor 302. The reactor 302 is in thermal communication with a thermal storage system 304. The thermal storage system 304 is in thermal communication with an energy conversion system 306 that is in communication with an external load 308.

[0076] The heat-producing reactor 302 may be any suitable type of nuclear reactor now known or later developed, such as a nuclear fission reactor or a fusion reactor. Such suitable reactors include, but are not limited to, fast neutron reactors, thermal neutron reactors, heavy water reactors, light water-moderated reactors, molten salt reactors, liquid metal-cooled reactors, organic-moderated reactors, water-cooled reactors, gas-cooled reactors, and breeder-burner reactors, to name a few. Furthermore, the heat-producing reactor 302 may comprise any suitable size of reactor, such as a small modular reactor, a micro-reactor, or even a gigawatt-sized reactor or larger. Furthermore, one or more reactors (which may be the same type of reactor or may be different types and sizes) may be utilized in an integrated energy conversion system.

[0077] The reactor boundary 310 is a physical barrier that surrounds the nuclear thermal plant 200 and is designed to secure the nuclear reactor 302. Often, the boundary 310 surrounds a nuclear island, which, as previously discussed in conjunction with the above embodiments, can be much smaller than a typical nuclear thermal plant. The thermal storage system 304 is located outside the reactor boundary 310. As discussed, the thermal storage system 304 can be any suitable type of thermal storage system 304 and can utilize any suitable type of thermal storage medium. For example, the thermal storage medium can be a eutectic solution, a phase change material, a miscible gap alloy, a mixture of metals (e.g., AlSi 12), cement-based materials, molten salts (e.g., chloride salts, sodium nitrate, potassium nitrate, calcium nitrate, NaKMg, or NaKMg-Cl, etc.), solid or molten silicon, or combinations of these or other materials.

[0078] In some examples, the thermal storage medium is also used as a heat transfer fluid in the energy transfer system 312 and / or the energy supply system 314. In this manner, the energy transfer system 312 may be in fluid communication with the energy conversion system 306, and the heat transfer fluid of the energy transfer system 312 may directly interact with the thermal storage medium of the thermal storage system 304. Similarly, in some examples, the energy supply system 314 may use the same heat transfer fluid as the thermal storage medium of the thermal storage system 304. In some cases, the thermal storage system 304 may be in direct fluid contact with the energy supply system 314.

[0079] The thermal storage system 304 is in thermal communication with the reactor 302 by an energy transfer system 312, which may be thermally coupled to the reactor 302 and the thermal storage system 304 by a heat exchanger. The energy transfer system 312 transfers thermal energy, typically through insulated conduits, to the thermal storage system 304, where the thermal energy is stored until needed.

[0080] The thermal storage system 304 is in thermal communication with an energy conversion system 306, such as by an energy supply system 314. The energy conversion system 306 may be of any suitable type, now known or later developed, capable of converting thermal energy into another form of useful energy. In one example, the energy conversion system 306 utilizes a steam turbine, which may operate in a Rankine cycle, to convert water vapor into mechanical work. Often, the water vapor is routed through the steam turbine, which rotates the shaft of a generator to produce electricity.

[0081] The energy supply system 314 may be any suitable combination of heat transfer devices. In some cases, one or more heat exchangers are associated with each of the thermal storage system 304 and the energy conversion system 306. A working fluid disposed within the energy supply system 314 (e.g., a fluid loop) receives thermal energy from the thermal storage system 304 at one or more heat exchangers associated with the thermal storage system 304 and provides thermal energy to the energy conversion system 306 at one or more heat exchangers associated with the energy conversion system. The energy supply system 314 may use any suitable working fluid, as described herein.

[0082] The energy conversion system 306 can be coupled to an external load 308 by an energy transmission system 316. The external load may be a public power grid. The energy conversion system 306 can transmit the generated power to the power grid, such as by high-voltage transmission lines that carry power from the energy conversion system to a demand center. Notably, the energy conversion system 306 is remote from the nuclear reactor 302 and is often outside the reactor site boundary 310, and often outside the EPZ. As described, the nuclear reactor 302 is decoupled from the energy conversion system 306, and any failure in the energy conversion system 306 does not negatively impact the nuclear reactor 302, or vice versa. In fact, even if the nuclear reactor 302 is shut down, such as for maintenance or refueling, the thermal storage system 304 can continue to supply thermal energy to the energy conversion system 306 to power the external load.

[0083] The relatively low cost of the thermal storage system 304 relative to the nuclear heat plant 200 makes it advantageous to scale up the thermal storage system 304 and scale down the nuclear heat plant 200. Furthermore, when utilizing low-pressure heat transport (e.g., molten salt as a heat transport medium), the relatively high-cost energy conversion device 306 can be located remotely relative to the nuclear heat plant 200, in which case the conversion device can be constructed more efficiently and without the restrictions that would be required if it were constructed on the reactor site. As used in this disclosure, the term "low pressure" is used to refer to pressures below about 3.5 MPa.

[0084] Additionally, the absence of a high-pressure system (e.g., greater than about 3.5 MPa) coupled to the reactor 302 can minimize the EPZ and reduce heat transport distances. In some examples, the thermal storage system 304 may be located adjacent to the reactor site but outside the site boundary 310. This minimizes heat transport distances while keeping the thermal storage system 304 and energy conversion system 306 outside the reactor site boundary 310 and outside of nuclear regulations.

[0085] 4, the nuclear reactor 302 may be similar to the reactor of FIG. 3 described above and is coupled to a thermal storage system 304, which may be substantially similar to the thermal storage system 304 of FIG. 3. The nuclear reactor 302 may also be coupled to a supplemental thermal storage system 402. In some examples, the thermal storage system 304 may optionally be thermally coupled to the supplemental thermal storage system 402. The nuclear reactor 302 may be configured to transport thermal energy to the thermal storage system 304, the supplemental thermal storage system 402, or both.

[0086] The thermal storage system 304 is coupled to an energy conversion system 306, as described herein, which is coupled to an external load 308, which may be any load, such as an electrical load or a thermal load.

[0087] The auxiliary thermal storage 402 may be located outside the reactor boundary 310 as shown, or in some cases may be located within the reactor boundary 310. In one embodiment, its function is to control the return and core inlet fluid temperatures to the reactor 302. The actual T in It is expected that T in If there is a difference between the temperature, the reactor control system may initiate a change to the reactivity to compensate for the temperature difference. For example, if the core inlet temperature is higher than expected, the reactor control system may reduce the reactivity to compensate for the higher than expected inlet temperature.

[0088] The auxiliary thermal storage 402 may be dedicated to the reactor and may be used to control and / or stabilize the core inlet temperature. For example, the auxiliary thermal storage 402 may be in thermal communication with the primary coolant loop within the reactor vessel. The primary coolant fluid may be in thermal communication with the primary coolant loop within the reactor vessel at an expected T in When the auxiliary thermal storage 402 has a different temperature than the primary coolant loop, the auxiliary thermal storage 402 can interact with the primary coolant loop to add or remove heat from the primary coolant. When the primary coolant interacts with the auxiliary thermal storage working fluid, the effect is for the primary coolant to reach thermal equilibrium with the auxiliary thermal storage fluid. Controlling the primary coolant temperature stabilizes the reactivity within the reactor core and smooths out any natural fluctuations.

[0089] In some examples, the auxiliary thermal storage system 402 is in direct thermal communication with the reactor 302, such as by transferring a portion of the reactor thermal energy to the auxiliary thermal storage 402. In other examples, the auxiliary thermal storage 402 is in thermal communication with the thermal storage system 304, and a portion of the thermal energy from the thermal storage system 304 is transferred to the auxiliary thermal storage 402 for use in regulating the reactor core inlet temperature.

[0090] Those skilled in the art will readily understand how these various systems are placed in thermal communication with one another and how these various systems are used to regulate the core inlet temperature.

[0091] Referring to FIG. 5 , a nuclear thermal plant 500 substantially as described above is shown. Notably, some reactor designs do not need to rely on heavy fuel assembly handling equipment. For example, in pool-type reactors, such as molten salt reactors, there are no fuel pins or fuel assemblies that need to be stored, moved, inserted, or removed from the reactor core. As a result, the fuel handling area 204 can be significantly reduced in size compared to that of a traditional nuclear power plant. Furthermore, many reactor designs that rely on a proliferation-resistant fuel cycle, such as breed-and-burn reactors or molten salt reactors, do not need to include a fuel handling area within the containment area. In these embodiments, the containment area 206 may be much smaller and may include only the reactor and smaller subsystems of the reactor. This results in a significantly smaller containment area 206, which translates into lower costs for construction, licensing, and operation.

[0092] Additionally, a smaller containment area 206 results in a smaller footprint at site boundary 310. Furthermore, an inherently safe reactor design minimizes site boundary 210, thereby minimizing the EPZ. In some cases, the EPZ boundary coincides with reactor site boundary 210, or in some cases, the EPZ is within site boundary 210. This allows the thermal storage system 208 and / or power generation system 212 to be located outside site boundary 210, while being relatively close to site boundary 210, reducing the heat transfer distance of the energy transfer system 214.

[0093] As shown, the thermal storage 208 may be in thermal communication with one or more loads 510. For example, the thermal storage system 208 may provide thermal energy for industrial heating 512, district heating 514, or power generation 212, among others.

[0094] Industrial heat 512 applications are varied and require heat at a variety of temperatures. Industrial heat applications can include fluid heating for food preparation, chemical manufacturing, reforming, distillation, hydrotreating, etc., requiring temperatures ranging from about 110°C to about 460°C. Similarly, curing and forming processes for coatings, polymer manufacturing, enamels, extrusion, etc. require heat ranging from about 140°C to about 650°C. Other processes include iron forming, smelting and steelmaking, and plastic and rubber manufacturing. This industrial heat can be supplied by the thermal storage system 208 as needed, in quality and quantity according to the specific industrial heat 512 requirements.

[0095] District heating 514 is a distribution system for supplying heat from a central source through a system of insulated pipes, such as for commercial and residential heating applications (e.g., for local space heating and hot water). This heat is generally in the lower temperature range and can be supplied by the thermal storage system 208, if desired.

[0096] As discussed above, the thermal storage system 208 can be coupled to a power generation plant 212, which can use the thermal energy from the thermal storage system 208 to generate electricity. The power generation system 212 can generate electricity on demand and load-follow demand from the power grid. In many cases, the power generation system 212 will generate waste heat, i.e., heat not used to generate electricity. This may be in the form of steam after passing through a steam turbine. This so-called waste heat may be recycled, for example, to provide district heating, which typically has lower temperature requirements than power generation 212 or industrial heat 512 applications. Similarly, waste heat from industrial heat 512 applications can be captured and / or recycled to provide heat for other uses, such as district heating, or can be returned to the thermal storage system 208.

[0097] In one embodiment, the thermal storage system 208 can simultaneously supply thermal energy to all required loads. This can be achieved by scaling the thermal storage to a size that can supply the thermal power demand from all expected loads. The loads are variable, i.e., for example, district heating 514 has a higher demand when the ambient temperature is colder, and electricity generation 212, such as for domestic use, increases during the day and decreases at night; therefore, the thermal storage system 208 can be sized and configured to supply all of the requirements of the required loads 510.

[0098] The thermal storage system 208 can include multiple storage facilities linked together. The multiple storage facilities can contain the same or different thermal storage media and can be maintained at different temperatures more suitable for different heat loads. For example, some industrial heat 512 applications require temperatures in excess of 800°C. In these cases, one or more individual storage facilities can store thermal energy above 800°C for supply to these high-temperature loads. Similarly, one or more individual storage facilities can supply relatively low-temperature thermal energy, such as between 100°C and 300°C, to loads requiring lower temperatures. Of course, the individual storage facilities can utilize different thermal storage media specifically designed to operate within the desired temperature range.

[0099] As an example, high temperature storage facilities may utilize molten salt as the heat storage medium, which may be formulated to be thermally stable up to 1000°C or higher. Low temperature storage facilities may utilize molten salt as the heat storage medium, due to its high heat capacity (approximately 4.2 J / (cm 3 Water can be used as a heat storage medium for the

[0100] Figure 6 shows various industrial heat applications where the required thermal energy can be supplied by a thermal storage system. As shown, district heating requires a temperature of approximately 50°C. This can be supplied by a thermal storage system having a thermal storage medium that is stable at approximately 50°C to compensate for the efficiency of heat transfer. The thermal storage medium can be maintained at a temperature higher than the required temperature, and a heat exchanger can be in thermal communication with the district heating working fluid, which can be air, water, oil, or some other suitable working fluid, for a predetermined time sufficient to heat the working fluid to the desired temperature sufficient for district heating.

[0101] Most nuclear reactors operating today operate in the lower half of the diagram, below about 300 °C. These reactors are thought to be capable of storing thermal energy at temperatures up to about 300 °C, making them suitable for many lower temperature heat load applications, including power generation.

[0102] However, for higher-temperature thermal applications (e.g., above 300 °C), traditional water-cooled nuclear power plants cannot generate temperatures in this range. However, there are reactors designed to operate at approximately 500 °C–550 °C, suitable for providing thermal energy up to operating temperatures. Other reactors are designed to operate at 750 °C–800 °C, providing heat in this range suitable for higher-temperature industrial applications. Still other reactors can operate at temperatures above 1000 °C, suitable for providing very high heat for industrial purposes. Fusion reactors, which promise operation at hundreds of millions of °C, can provide even higher thermal energy than fission reactors.

[0103] Referring to FIG. 7 , an integrated energy system 700 is shown in which a thermal energy storage system 702 is supplied with thermal energy from various heat sources. The thermal energy storage system 702 can be substantially similar to those described previously herein. One or more nuclear reactors 704, 706, 708 can be in thermal communication with the thermal energy storage system 702. For example, when constructing the integrated energy system 700, as shown, a single, first nuclear reactor 704 may be constructed utilizing currently existing nuclear reactor technology. The thermal energy storage system 702 can be coupled to an energy conversion system 710 that converts thermal energy into electrical power, such as to provide electrical power to an external load.

[0104] In some cases, a second reactor 706, a third reactor 708, or more reactors can be coupled to a common thermal energy storage system 702. In some embodiments, one or more thermal energy sources, which may be multiple nuclear reactors, a wind energy system 712, a solar energy system 714, a geothermal energy system, or any combination of thermal energy sources, can be combined and coupled to the thermal energy storage system 702 as part of the integrated energy system 700. The thermal energy sources provide thermal energy to the thermal energy storage system 702 via any suitable techniques and components, which may be different for different thermal energy sources. In some cases, the thermal energy storage system 702 utilizes a working fluid to store thermal energy, which may be the same working fluid used as a heat transfer fluid to provide thermal energy from the thermal energy source to the thermal energy storage system 702.

[0105] As base load electrical demand increases over time, thermal energy storage system 702 can be scaled up to increase thermal energy storage capacity. Similarly, nuclear reactors can also be scaled and upgraded to utilize different technologies, or additional reactors can be added as heat sources and coupled to a common thermal energy storage system 702. As an example, a sodium fast reactor can be built and coupled to thermal energy storage system 702. As demand from external load 716 increases, or as reactor technology advances in its technology readiness level, another reactor can be built and coupled to thermal energy storage system 702. As an example, a molten salt reactor, small modular reactor, sodium pool reactor, or some other type of nuclear reactor can be built and coupled to thermal energy storage system 702 in addition to, or instead of, an existing reactor coupled to thermal energy storage system 702.

[0106] In many instances, multiple reactors can be built, each with its own reactor vessel, head, and site boundary, and everything beyond the site boundary can be common to the multiple reactors. Of course, pipes and valves can be used to couple the reactors to the thermal energy storage system 702. The energy supply system can use common or different heat transfer media to couple the reactors to the thermal energy storage system 702. Utilizing common rest-of-plant components, such as a common thermal energy storage system 702, a common steam plant, a common heat transport, and a common energy conversion system 710, provides efficiencies in scaling the size of the thermal energy storage system 702 compared to building separate nuclear power plants to provide electrical power, each with its own unique rest-of-plant requirements.

[0107] Providing multiple reactors coupled to a common thermal energy storage system 702 provides the added benefit of ease of reactor maintenance. One reactor can be taken offline, such as for maintenance or refueling, without shutting down the entire system. In some cases, one or more thermal energy generation systems (e.g., nuclear reactor, wind energy system 712, solar thermal energy system 714, geothermal system, etc.) can be decoupled from the thermal energy storage system 702 and the energy conversion system 710, such that one or more thermal energy systems can be taken offline without affecting the rest of the apparatus or interrupting the supply of energy to the external load 716.

[0108] In one example, the heat transfer fluid is molten salt throughout the entire energy system, except perhaps for the reactor core, which can use any of a number of coolants. For example, the energy transfer system 214, which carries thermal energy from the nuclear heat plant 704 to the thermal energy storage system 702, can utilize molten salt as its working fluid. Similarly, the heat storage medium within the thermal energy storage system 702 can also be a molten salt, which can be the same salt as the working fluid of the energy transfer system 214. Furthermore, the energy delivery system 216, which transfers heat from the thermal energy storage system 702 to the energy conversion system 710, can also be a molten salt. Of course, the molten salts used throughout the system can be the same salt or can have different formulations specific to their intended uses.

[0109] For example, if the thermal energy storage system 702 is to supply heat to a district heating load, a relatively low temperature is required, and a salt (or other working fluid) specially formulated to excel at the required lower temperatures may be used as the working fluid to supply the heat used for district heating.

[0110] Additionally, other forms of thermal energy may be coupled to the thermal storage system, such as solar thermal energy 714 or wind energy 712. In many cases, the thermal energy storage system 702 is agnostic as to the thermal energy source and can be coupled to many different types of thermal energy generators, such as any of a number of nuclear thermal plants, solar plants, wind plants, geothermal plants, hydroelectric plants, or other types of heat generating plants.

[0111] 8 illustrates an exemplary energy system 800 in which multiple thermal energy sources are thermally coupled to a thermal energy storage system 702. The thermal energy sources can be any one or more of multiple thermal energy systems, such as a nuclear reactor heat plant 704, a solar thermal plant 714, a wind energy plant 712, or other types of thermal energy generation plants, or any combination of thermal energy generation plants.

[0112] The thermal energy plant supplies thermal energy to a thermal energy storage system 702, which stores the thermal energy by any suitable means, such as a eutectic solution, a phase change material, a miscible gap alloy, a mixture of metals, a cement-based material, a molten salt (e.g., chloride salts, sodium nitrate, potassium nitrate, calcium nitrate, NaKMg, or NaKMg-Cl, etc.), solid or molten silicon, or a combination of these or other materials. In some embodiments, the thermal energy storage system 702 utilizes the same working fluid as the thermal energy transfer fluid that receives thermal energy from one or more of the thermal energy generation plants. In some cases, the thermal energy transfer fluid is the same as and in fluid communication with the thermal storage medium. In this example, the intermediate heat transfer loop may optionally be omitted, and the thermal storage medium may receive thermal energy directly from the thermal energy generation plant through a single heat transfer loop. While the thermal energy plant can be in thermal communication with the thermal energy storage system 702 through one or more heat exchangers, in some embodiments, a separate heat exchanger is used for each thermal energy plant to couple the thermal energy plant to the thermal energy storage system 702. In some instances, this allows multiple thermal energy sources to be added or removed from system 800 as needed.

[0113] In some embodiments, the auxiliary power system 802 can be coupled to the thermal energy storage system 702. The thermal energy storage system 702 can selectively supply thermal energy to the auxiliary power system 802, which uses the thermal energy to generate electrical power, such as to power one or more of the nuclear reactors 704, 706, 708. In some cases, the auxiliary power system 802 can provide blackstart capability to one or more of the nuclear reactors. This can provide dedicated power to the reactors in the event of a power outage or to start the reactors even when electricity from the power grid is unavailable. This further isolates the reactors from the rest of the plant and from the power grid. Of course, the auxiliary power system 802 can provide backup power to any of the thermal energy generation plant, the thermal energy storage system 702, or any other systems that benefit from uninterruptible backup power.

[0114] The thermal energy storage system 702 may be thermally coupled to an energy conversion system 710, which may generate energy for an external load, as described above. Often, the external load 716 requires either thermal energy or electrical power, either of which may be supplied by the energy conversion system 710. In some cases, the energy conversion system 710 will convert thermal energy to electrical power via a steam generator and turbine. However, in some cases, the thermal energy storage system 702 may supply compressed, heated gas directly to the turbine, thereby eliminating the steam generator typically used in turbine power plants.

[0115] As an example, the thermal energy storage system 702 or the energy conversion system 710 can use a heat storage medium to heat a working gas, such as nitrogen, argon, or hydrogen. The working gas can be heated and compressed, such as to 4 atm, 5 atm, or 6 atm, but in some embodiments is pressurized to less than 4 atm. The working gas can be heated to temperatures such as 600°C, 650°C, 700°C, 725°C, or 750°C or higher. The working gas can be fed directly to a turbine, where it can then expand and drive the turbine. In some embodiments, the turbine operates in a Brayton cycle or a regenerative Brayton cycle. The gas pressure ratio can be selected and controlled to improve Brayton cycle efficiency. Of course, other working gases, such as immiscible salts, can be used, which vaporize at the operating temperature and can be used to drive the turbine.

[0116] FIG. 9 illustrates an embodiment of an integrated energy system 900 in which a nuclear heat plant 200 supplies thermal energy to a thermal storage system. While a single nuclear heat plant 200 is illustrated, it should be understood that two or more nuclear heat plants and / or other thermal energy plants can be combined to supply thermal energy to a thermal energy storage system 702. The thermal energy storage system 702 then supplies thermal energy to one or more loads 510, which may include loads for power generation 212, district heating 514, or industrial heat 512. In some cases, the loads 510 may be relatively low for days or weeks, causing the thermal energy storage system 702 to become thermally saturated. That is, the thermal energy storage system 702 may not be able to receive any additional heat from the nuclear heat plant or other connected thermal energy source. Therefore, the thermal energy generated by the thermal energy generation plant can be transferred to some other auxiliary heat use 902 that provides benefits. In some cases, the excess heat is rejected to the atmosphere, but in other cases, the excess heat beyond what the thermal storage system can receive can be used for other processes, such as water desalination or hydrogen production, among others. Of course, auxiliary heat utilization 902 can be supplied with thermal energy even if the thermal storage system is not saturated. For example, thermal energy from a thermal energy source may be supplied to thermal energy storage system 702 and used for auxiliary heat utilization 902 at the same time.

[0117] These auxiliary heat uses 902 may receive a portion of the thermal energy before it is provided to the thermal energy storage system 702, or these auxiliary heat uses 902 may selectively receive all of the generated thermal energy, for example, if the thermal storage system is full or if the auxiliary heat uses 902 are deemed a higher or better purpose for the thermal energy than storing the thermal energy for later use.

[0118] In some embodiments, the thermal energy storage system 702 is located at an elevation above the power generation system 212. For example, the thermal energy storage system 702 may be built on a hill so that it is at a higher elevation than the power generation system 212. This arrangement utilizes a hybrid energy storage mode by combining both thermal energy and gravity-induced pressure on the downstream system due to elevation changes. The hybrid energy storage mode increases the overall energy density. For example, in a typical steam turbine system, one or more pumps are required to pump the working fluid through the turbine system. The pumps are generally sized for peak loads and selected to meet peak load demands by pumping a higher volume per unit time of working fluid through the turbine system. By relying on gravity, the system can send additional heat through the steam generator and then to a cold storage tank. In some embodiments, this arrangement can reduce the required size of one or more pumps or eliminate one or more pumps in the steam turbine system.

[0119] In some embodiments, a currently existing containment site may be suitable for constructing a nuclear heat plant to be coupled to a thermal storage system. Currently, there are many nuclear reactor sites that are no longer in operation or are scheduled to be decommissioned and cease operation. These locations can be referred to as brownfield sites (vacant lots for redevelopment, existing industrial sites), a nomenclature defined by the Environmental Protection Agency as real estate whose expansion, reuse, or development may be complicated by the presence or potential presence of hazardous materials, contaminants, or pollutants. A decommissioned nuclear reactor site is one type of physical site that falls within the definition of a brownfield site.

[0120] However, nuclear reactor brownfield sites offer several advantages to the systems and methods disclosed or described herein. For example, nuclear reactor brownfield sites have civil works already in place, such as roads, utilities (e.g., power lines, sewer, water, etc.), perimeter security, containment buildings, pipes, valves, ancillary buildings, etc. Many of these structures can be reused for a nuclear thermal plant, significantly reducing the time and cost required to build and commission a nuclear thermal plant.

[0121] Many nuclear reactor brownfield sites have containment structures designed to house high-pressure reactors, such as light water reactors ("LWRs"). These containment structures are designed far beyond what newer generation nuclear thermal plants would require, many of which operate at relatively low pressures compared to LWRs. The thermal energy storage system 702 can be located remotely from the reactor brownfield site and thermally coupled to the nuclear thermal plant, such as via a heat transfer fluid loop, as described herein. Passages can be created within the containment structure to allow the heat transport medium to exit the containment structure and deliver thermal energy to the thermal energy storage system 702 located remotely from the reactor site.

[0122] Existing containment structures can be configured to house one, two, or more nuclear thermal plants. For example, multiple reactors can be constructed in a single containment structure, sharing containment structures, fuel handling systems, and other components. The containment structure may be divided into two or more reactor rooms to house multiple reactors and their associated support equipment. Two or more reactors can share fuel accumulation areas, subsystems, reactor core refueling / defueling systems, and fuel polishing systems, among other things.

[0123] In some cases, it is desirable to operate a nuclear reactor at full power. The systems and methods described herein allow the reactor to remain at continuous full power by decoupling the reactor from the thermal storage and power generation systems. The reactor can continuously supply thermal energy to a thermal storage system, which can be sized to store and supply more energy than the reactor can supply. Thus, the reactor can slowly "charge" the thermal storage system over time. If the reactor generates excess heat that the thermal storage system cannot accept, the excess heat may be diverted and used for auxiliary purposes, such as industrial process heat, fresh water production, hydrogen production, or some other beneficial purpose. Of course, the excess heat may alternatively or additionally be vented to the atmosphere.

[0124] 10 illustrates an exemplary embodiment of an integrated energy system having a nuclear thermal plant 200 coupled to a thermal energy storage system 702. Additional hybrid energy sources 1002, such as wind, solar, geothermal, wave energy, or other renewable energy sources, can be similarly coupled to the thermal energy storage system 702. As shown, the nuclear thermal plant 200 is located within the reactor boundary 210 and EPZ, while the remaining systems, such as the thermal energy storage system 702 and the power conversion system 212, are located outside the reactor boundary 210 and EPZ.

[0125] The traditional use of nuclear power plants is the generation of electricity. However, many newer Generation IV nuclear plants are designed with exit temperatures exceeding 500°C, significantly higher than the exit temperature of light water reactors (LWRs). Thus, the potential applications of this high-grade heat extend far beyond power generation. In this illustrated structure, the nuclear reactor 200 is used as a heat source routed to a separate thermal energy storage system 702 located outside the reactor boundary 210. In addition to being carbon-free or at least low-carbon, combined with the proliferation-resistant characteristics of newer nuclear reactors, this integrated energy system 1000 structure enables many beneficial features, including: (1) reduced reactor and total system costs; (2) enabling flexible power demand (load) following and “profit following” in the power grid with greater penetration of renewable energy; (3) providing high-temperature process heat at a cost competitive with natural gas, which is not currently possible with LWRs; and (4) enabling hydrogen production through high-temperature electrolysis.

[0126] These capabilities will enable dramatic carbon reductions in the industrial process and transportation sectors, which currently account for approximately 75% of global greenhouse gas emissions.

[0127] One of the current obstacles facing nuclear power plants is the upfront construction and licensing costs associated with building and starting up a nuclear plant. One of the primary cost drivers in nuclear plant construction is not the nuclear technology itself, but rather the cost of the large-scale construction project, which is regulated by strict nuclear standards. Therefore, one of the greatest promises for capital cost reduction lies in plant design, not necessarily technological advances in the reactor itself. As described herein, by significantly simplifying and reducing the scope and complexity of the reactor site construction project, the primary cost drivers associated with building a typical nuclear power plant are dramatically reduced. Various structural embodiments described herein reduce the scope of the nuclear power plant and reactor construction project to its most basic form. The simplified nuclear reactor becomes a producer of thermal energy, referred to herein as a nuclear thermal plant.

[0128] In one embodiment, the interface between the nuclear heat plant and the rest of the integrated energy system is a heat exchanger, and the rest of the system components downstream of the heat exchanger are functionally and spatially separated from the nuclear heat plant, in a structure where the rest of the plant, including the thermal energy storage and power conversion systems, can be built and operated in a less regulated, less expensive, and fully commoditized environment.

[0129] Molten salt thermal storage systems are relatively inexpensive, often an order of magnitude cheaper than battery storage, and have achieved commercial readiness at the GWh scale. Suitable thermal storage systems are currently being used in support of the concentrated solar power industry. Furthermore, due to the significant safety advantages of the advanced reactors described herein, very small EPZs are possible, which allows for the placement of these reactors in closer proximity to heat consumers.

[0130] The described integrated energy system also addresses other challenges facing nuclear power in current and future electricity markets. For example, as an increasing proportion of electricity is generated by intermittent renewable energy sources, there are large fluctuations in power supply, with overproduction typically occurring between 9 a.m. and 4 p.m., and solar energy pushing electricity prices to very low or even negative territory. Current nuclear power plants typically have limited flexibility for rapid load-following and, in some cases, are driven to maintain relatively high capacity factors to achieve a low level cost of electricity (LCOE). Thus, even if a nuclear power plant can meet fluctuating daily electricity demand, its LCOE increases, making it difficult to compete with alternative technologies. Salt thermal storage allows many types of nuclear heat plants to operate at (or very close to) 100% capacity factor, store energy in thermal energy storage tanks, such as salt tanks, and sell the electricity during periods of high demand and prices.

[0131] An important consideration in reducing greenhouse gas emissions is the extension of decarbonization to other industrial processes. Energy consumption, primarily in the form of heat, is significant in this sector, with petroleum and chemicals being the major consumers. The integrated energy system described herein, with high outlet temperatures of approximately 510°C to 540°C or higher and heat storage media compatible with these temperatures, offers the opportunity to supply heat to numerous consumers up to approximately 500°C, such as oil refineries, various chemical plants, soda ash production plants, pulp and paper plants, and food processing plants. There is also significant potential for cogeneration power plants producing both heat and electricity.

[0132] The transportation sector accounts for the second largest share of global energy consumption after industrial manufacturing. Until recently, transportation was fueled exclusively by gasoline, and clean nuclear energy was not involved in the sector. This is changing with the recent advent of hydrogen-powered, battery- and fuel-cell-powered electric vehicles. An integrated energy system such as that described herein can provide both of these products without carbon, making a significant impact on the decarbonization of the transportation sector.

[0133] The integrated energy systems described herein can produce hydrogen using high-temperature electrolysis and heat. Stored thermal energy can be used to generate steam from water, and hybrid energy, such as electricity, can be used to raise the temperature in the electrolyzer to 750°C-900°C, such as through ohmic heating. In some embodiments, a heat exchanger in the electrolyzer can recover heat from the hydrogen and oxygen streams to reduce the amount of ohmic heating energy required to maintain the electrolyzer temperature at a desired temperature or, in some cases, above a threshold temperature. Furthermore, the described integrated energy systems can simultaneously generate both electricity, such as to charge a car battery, and hydrogen. For example, when electricity is not needed, the generated thermal energy can be used to generate additional hydrogen, which can then be stored for distribution over long distances, as is currently done with gasoline. Unlike gigawatt-scale thermal storage, which is limited to periods of a few hours and relatively short transport distances, hydrogen can be stored for much longer periods and transported over long distances. Thus, integrated energy systems can be used to generate hydrogen, which can be stored for long periods of time, transported long distances, and later used as a fuel source.

[0134] In some embodiments, the nuclear thermal plant and integrated energy system can be coupled, solely or partially, to a hydrogen production plant and can use an electrolysis process that utilizes electrical power to split water into hydrogen and oxygen. In some examples, the integrated energy system can provide thermal power to the generated steam for use in hydrogen steam reforming of natural gas processes. In some cases, the high-temperature electrolysis process is a process in which a significant amount of the electrolysis energy can be provided by heat, thereby reducing the amount of electrical energy and therefore the cost of producing hydrogen. In some cases, the high-temperature electrolysis process utilizes thermal energy having a temperature of approximately 800°C, which can be provided by an integrated energy system as described herein.

[0135] FIG. 11 illustrates an integrated energy system 1100 having a nuclear block 1102 in communication with an integrated energy storage block 1104. The integrated energy storage block 1104, in turn, is in communication with a power block 1106. The power block 1106 can be in communication with an external load 1108. According to an embodiment, the nuclear block 1102 comprises one or more nuclear reactors, such as a nuclear thermal plant, having a reactor boundary 1110 surrounding the nuclear island, as described herein. One or more nuclear thermal plants may be included as part of the nuclear block 1102, or one or more nuclear thermal plants may be coupled to the integrated energy storage block 1104 and maintain their own separate reactor boundary 1110. The integrated energy storage block 1104 may be comprised of any suitable thermal storage, as described herein, and may, by way of example, include a salt tank that relies on a phase change material to store thermal energy at a stable temperature to receive thermal energy from the nuclear block. The integrated energy storage block 1104, also referred to herein as a thermal energy storage system or thermal energy storage system, is separated from the nuclear block 1102 by a boundary 1112, which may be defined by the reactor site boundary 1110. In some examples, the primary communication between the nuclear block 1102 and the integrated energy storage block 1104 is one or more heat exchangers that transfer thermal energy generated by the nuclear block 1102 to the integrated energy storage block 1104.

[0136] The integrated energy storage block 1104 is in thermal communication with the power block 1106. The thermal communication may be performed by one or more heat exchangers configured to transfer thermal energy from the integrated energy storage block 1104 to the power block 1106. The power block 1106 may, for example, convert the thermal energy into electrical power, which may be performed by a turbine, such as a steam turbine, or some other type of thermal-to-electrical energy conversion system. The power block 1106 can utilize the thermal energy to generate and transfer electricity to an external load 1108, such as a power grid.

[0137] As the world moves away from coal-fired power plants for any of a number of different reasons, decommissioned coal-fired power plant equipment can be utilized by other energy sources. For example, when a coal-fired power plant is decommissioned, the equipment downstream of the boiler is tolerant of the heat source. For example, the turbine block, switchyard, capacitors, generators, and electrical wiring can all still be used with another source of thermal energy. These valuable assets become orphan assets when a coal-fired power plant is decommissioned, creating an opportunity for another, carbon-free source of thermal energy to utilize the stranded assets and continue to generate electricity.

[0138] According to some embodiments, the coal-fired rest of the plant power block (e.g., everything downstream of the boiler) includes equipment such as the boiler drum, pendant superheater, high-pressure turbine, reheater, intermediate-pressure turbine, low-pressure turbine, condenser, feed pumps, deaerators, feed heaters, economizers, cooling towers, generators, transformers, and grid, along with associated piping, instrumentation, and controls. These stranded assets are tolerant of a thermal energy source that can be supplied by the integrated energy storage block 1104 (e.g., a thermal storage system), as described herein.

[0139] The integrated energy storage block 1104 may receive thermal energy from any of a number of thermal energy sources, such as one or more nuclear thermal plants, solar thermal energy, geothermal energy, wind thermal energy, wave energy, or any other suitable generator of thermal energy. According to an embodiment, the integrated energy storage block 1104 allows any form of thermal energy to be combined and made usable with any form of power block 1106, providing the further advantage of decoupling the nuclear block 1102 from the power block 1106.

[0140] This structure offers many advantages. For example, there is regulatory isolation between the nuclear block 1102 and all equipment downstream of the integrated energy storage block 1104, and flexibility in matching the nuclear block 1102 to the electric power block 1106. For example, the nuclear block 1102 does not have to match the electric power block 1106 in terms of power output. The nuclear block 1102 operates at full power and transfers thermal energy to the integrated energy storage block 1104, which can then provide the thermal energy to drive the turbine of the electric power block 1106 in any suitable manner. Thus, the operation of the electric power block 1106 is completely independent of the operation of the nuclear block 1102.

[0141] According to one embodiment, the nuclear block 1102 can be operated at 100% capacity, but because the nuclear block 1102 is decoupled from the power block 1106 by the integrated energy storage block 1104, the power block 1106 can fully load follow the power demand.

[0142] The described structure also provides advantages in design efficiency. It is no longer necessary to match a reactor to a specific power block 1106. A generic reactor can be matched to a generic power block, eliminating the need to develop a new reactor to match power to each optional power block. Generic reactor refers to a reactor of any design and power output. Generic power block refers to a thermal energy to electricity conversion system of any design, size, type, and power output, including, for example, a steam generator.

[0143] In some embodiments, the integrated energy storage block 1104 is designed to accept the output of the nuclear block 1102 and provide thermal energy according to the demands of the power block 1106. In some embodiments, the described structure allows a single reactor design or a combination of multiple reactor designs to be fitted to the power block 1106. For example, if the power block requires 1600 MW of steam for a turbine, that need can be met with one 1600 MW reactor, two 800 MW reactors, one 1200 MW reactor, and one 400 MW reactor, etc. In some examples, the integrated energy block 1104 acts as a power aggregator from one or more reactor designs, thus allowing flexibility, scalability, and time independence of the coupling of the power block 1106 to one or more reactors by relying on the integrated energy block 1104 as a buffer. This further allows the nuclear block 1102 and the power block 1106 to be completely decoupled and independent from a design, construction, and operation standpoint. A further advantage is that this structure allows for the use of a single reactor design, such as a 400 MW plant, used in conjunction with multiple types of power blocks (e.g., 400 MW, 800 MW, 1200 MW, 1600 MW, 2000 MW, 2400 MW, etc.). In some embodiments, true mismatches may exist between the nuclear block 1102 and the power block 1106; for example, a reactor block 1102 outputting 1600 MW can be matched with a power block 1106 with 1500 MW. In other words, the nuclear block 1102 can have a thermal power output, and the power block 1106 can have a thermal power input that is greater or less than the thermal power output of the nuclear block 1102. Stated another way, reactor block 1102 may have a different nameplate capacity than the nameplate capacity of power block 1106. As used herein, nameplate capacity is the full load sustaining power output of the facility.Nameplate capacity is typically a number registered with a regulatory body to classify the power output of a station and is usually measured in watts, megawatts, or gigawatts. When used to describe a power block 1106, nameplate capacity may also be used to refer to the power input (input power) to the power block 1106 that can be converted to electrical power when the power block 1106 operates at full output.

[0144] This type of mismatch can be addressed in the manner described herein, by using the excess thermal energy for other purposes, by scaling the integrated energy storage block, and by planning nuclear outages while still providing thermal energy from the integrated energy storage block to the power block, or by allowing the nuclear block 1102 to charge the integrated energy storage block 1104 during times of reduced power demand, to name a few. In some cases, the power block 1106 can be operationally scaled back to a power output lower than 100% capacity, while the nuclear block 1102 can operate at 100% operational capacity.

[0145] Similarly, the nuclear reactor block 1102 may be coupled to an integrated energy storage block 1104 with a mismatch between the thermal power generation capacity of the nuclear block 1102 and the thermal storage capacity of the thermal storage block 1104. In other words, the nuclear block 1102 may have a generation capacity that is less than the storage capacity of the thermal storage block. In some cases, the generation capacity of the nuclear reactor block may be on the order of 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% of the storage capacity of the thermal storage block.

[0146] In some cases, the nuclear block 1102 generates thermal energy at a temperature that may not be ideal for the power block 1106. As an example, the nuclear block 1102 may provide an outlet temperature of 500° C., and the power block 1106 may require steam at 550° C. In these cases, the temperature shortfall can be made up by (1) a peaker tank that can heat the thermal storage medium to a higher temperature, (2) adding additional thermal energy to the steam before it is sent through the turbine, (3) operating the turbine at a lower efficiency, or utilizing some other solution to address the temperature mismatch.

[0147] In some embodiments, hybrid technologies can be used to supplement the thermal energy of the nuclear block 1102. For example, if the power block 1106 requires a greater inlet steam temperature than the nuclear block 1102 can provide, an alternative technology such as ohmic heating, natural gas, hydrogen, or some other energy source can be utilized to peak the steam temperature and operate the power block 1106 at an appropriate efficiency.

[0148] According to one embodiment, utilizing the isolated power block 1106 asset in conjunction with a nuclear thermal plant in an integrated energy system 1100 provides numerous benefits. For example, the site is already approved and operational, the layout is already in place, allowing hundreds of millions of dollars of equipment to be further utilized in carbon-free power generation operations rather than being scrapped, and the site is already connected to transmission infrastructure and the power grid, among other benefits.

[0149] The above description of combining nuclear power block 1102 and integrated energy storage block 1104 with stranded coal power block 1106 assets is equally applicable to stranded natural gas assets. As gas-fired power plants are decommissioned for any of a number of different reasons, the power block from these plants can be harnessed by coupling the power block 1106 with the integrated energy storage block 1104, which provides thermal energy to drive the turbines of the gas-fired power plant. The integrated energy storage block 1104 can receive thermal energy from any of a number of different sources, such as one or more nuclear reactors, solar thermal energy, wind energy, geothermal energy, hydroelectric energy, or any other suitable thermal energy source.

[0150] In some instances where the power block 1106 requires a higher temperature than the output temperature of the integrated energy storage block 1104, the decommissioned gas-fired power plant will have an available source of natural gas that can be used to peak the temperature of the thermal storage medium or turbine working fluid to improve the efficiency of the turbine cycle. Additionally, the power block 1106 may itself generate power at a lower efficiency due to a lower than optimal inlet steam pressure, but can redirect some of the generated power to peak the inlet steam temperature, gradually increasing its efficiency as the inlet steam rises to a more ideal temperature for the power block.

[0151] According to one embodiment, brownfield sites offer the opportunity to utilize stranded units by combining them with an integrated energy storage block 1104 and nuclear block 1102. By utilizing the existing infrastructure available on brownfield sites, it becomes possible to rehabilitate and develop otherwise difficult-to-use sites into carbon-free energy production facilities at a much lower cost than new construction and with reduced licensing and commissioning time and costs, allowing the sites to be redeveloped for active use.

[0152] The embodiments described herein provide an integrated energy system that decouples thermal energy sources from energy conversion systems, providing a modular, scalable, and efficient system that can be used to meet base and peak electrical load demands, as well as industrial process heat. One or more thermal energy sources, such as one or more nuclear reactors of various types, solar plants, geothermal energy sources, among others, can be coupled to a shared rest of the plant system, such as a thermal storage and energy conversion system.

[0153] Those skilled in the art will recognize that any process or method disclosed herein can be modified in many ways. The process parameters and sequences of the processes described and / or illustrated herein are given by way of example only and can be changed as desired. For example, although the processes illustrated and / or described herein may be shown or described in a particular order, these processes do not necessarily have to be performed in the order illustrated or described.

[0154] The various exemplary methods described and / or illustrated herein may omit one or more of the steps described or illustrated herein or may include additional steps in addition to those disclosed. Furthermore, the steps of any method disclosed herein may be combined with any one or more steps of any other method disclosed herein.

[0155] Unless otherwise specified, the terms "connected" and "coupled" (and their derivatives) as used in the specification and claims should be interpreted as allowing for both direct and indirect (i.e., via other elements or components) connections. Furthermore, the terms "a" or "an" as used in the specification and claims should be interpreted as meaning "at least one of." Finally, for ease of use, the terms "including" and "having" (and their derivatives) as used in the specification and claims are interchangeable with the word "comprising" and shall have the same meaning.

[0156] As used herein, the term "or" is used inclusively to refer to items in alternative and combination. As used herein, letters such as numbers refer to similar elements.

[0157] The embodiments of the present invention shown and described herein are provided by way of example only. Those skilled in the art will recognize numerous adaptations, modifications, variations, and substitutions without departing from the scope of the present disclosure. Several alternatives and combinations of the embodiments disclosed herein may be utilized without departing from the scope of the disclosure and invention disclosed herein. Accordingly, the scope of the present disclosure is to be defined solely by the appended claims and their equivalents. The present disclosure also includes the following numbered clauses:

[0158] 1. 1. A system comprising: a nuclear reactor located on the reactor site; a reactor site boundary surrounding the reactor, the reactor site boundary being defined by one or more barriers that restrict access to the reactor site; a thermal energy storage system located outside the reactor site boundary and in thermal communication with the reactor; a generator in thermal communication with the thermal energy storage system, the generator being located outside the reactor site boundary; A system comprising:

[0159] 2. 10. The system of claim 1, further comprising a containment building, wherein the reactor is enclosed within the containment building.

[0160] 3. 10. The system of claim 1, further comprising a fuel handling area, said fuel handling area being located within said reactor site boundary.

[0161] 4. 2. The system described in clause 1, wherein the thermal energy storage system is in thermal communication with the nuclear reactor by an energy transfer system.

[0162] 5. 5. The system described in clause 4, characterized in that the energy transfer system includes a fluid loop, the fluid loop forming a closed loop between the nuclear reactor and the thermal energy storage system.

[0163] 6. The system described in clause 5, characterized in that the fluid loop of the energy transfer system is in thermal communication with the reactor by a first heat exchanger and in thermal communication with the thermal energy storage system by a second heat exchanger.

[0164] 7. 6. The system of clause 5, wherein the fluid loop contains a working fluid.

[0165] 8. 8. The system of claim 7, wherein the working fluid comprises a chloride salt.

[0166] 9. 8. The system of claim 7, wherein the working fluid comprises sodium nitrate.

[0167] 10. 8. The system of claim 7, wherein the working fluid comprises a eutectic solution.

[0168] 11. 8. The system of claim 7, wherein the working fluid comprises a phase change material.

[0169] 12. 8. The system of claim 7, wherein the working fluid comprises a miscible gap alloy.

[0170] 13. 8. The system of clause 7, wherein the working fluid comprises a molten metal or metal alloy.

[0171] 14. 7. The system of claim 6, wherein the first heat exchanger or the second heat exchanger is a shell-and-tube heat exchanger.

[0172] 15. 7. The system of claim 6, wherein the first heat exchanger or the second heat exchanger is a double-pipe heat exchanger.

[0173] 16. 7. The system according to clause 6, characterized in that the first heat exchanger or the second heat exchanger is a plate heat exchanger.

[0174] 17. 10. The system of claim 1, further comprising a hydrogen generator coupled to the thermal energy storage system.

[0175] 18. 10. The system of claim 1, wherein the reactor site boundary includes a fence.

[0176] 19. 2. The system of claim 1, wherein the reactor is a fast neutron reactor.

[0177] 20. 10. The system of claim 1, wherein the reactor is a breeder reactor.

[0178] twenty one. 2. The system of claim 1, wherein the reactor is a thermal neutron reactor.

[0179] twenty two. 2. The system of claim 1, wherein the nuclear reactor is a heavy water reactor.

[0180] twenty three. 10. The system of claim 1, wherein the nuclear reactor is a light water reactor.

[0181] twenty four. 2. The system described in clause 1, characterized in that the nuclear reactor is a molten salt reactor.

[0182] twenty five. 10. The system of claim 1, wherein the nuclear reactor is a liquid metal cooled nuclear reactor.

[0183] 26. 2. The system described in clause 1, wherein the reactor is a gas-cooled reactor.

[0184] 27. 2. The system described in clause 1, characterized in that the thermal energy storage system is coupled to an energy conversion system having a thermal power input greater than the thermal power output of the nuclear reactor.

[0185] 28. 2. The system described in clause 1, characterized in that the thermal energy storage system is a low-pressure system.

[0186] 29. 29. The system of clause 28, wherein an energy transport system is configured to transfer thermal energy from the nuclear reactor to the thermal energy storage system.

[0187] 30. 30. The system according to clause 29, characterized in that the energy transport system is a low pressure system.

[0188] 31. 2. The system described in clause 1, characterized in that the generator is in thermal contact with the thermal energy storage system by an energy supply system.

[0189] 32. 32. The system according to clause 31, characterized in that the energy supply system comprises a closed fluid loop.

[0190] 33. 33. The system of clause 32, wherein the closed fluid loop comprises a molten salt.

[0191] 34. 32. The system of claim 31, wherein the energy supply system includes a working fluid in direct contact with a heat storage medium in the thermal energy storage system.

[0192] 35. 2. The system of claim 1, wherein the generator is a steam turbine.

[0193] 36. 36. The system of claim 35, wherein the steam turbine converts steam into mechanical work.

[0194] 37. further comprising a generator coupled to the steam turbine by an output shaft of the steam turbine; 37. The system according to clause 36, characterized in that the mechanical work causes the generator to generate electrical power.

[0195] 38. 38. The system according to clause 37, wherein the generator is configured as a load following power generation system.

[0196] 39. 10. The system of claim 1, wherein the reactor is a first reactor and the system further includes a second reactor.

[0197] 40. the second reactor is located on a second reactor site within a second reactor site boundary; 40. The system of clause 39, wherein the thermal energy storage system and the generator are located outside the second reactor site boundary.

[0198] 41. 10. The system of claim 1, further comprising an auxiliary thermal storage system in thermal communication with the nuclear reactor.

[0199] 42. 42. The system of clause 41, wherein the auxiliary heat storage system is configured to adjust the inlet temperature of the reactor core.

[0200] 43. 10. The system of claim 1, further comprising a solar thermal energy system in thermal communication with the thermal energy storage system.

[0201] 44. The system of clause 1, further comprising an emergency planning area around the nuclear reactor, the thermal energy storage system and the generator being located outside the emergency planning area.

[0202] 45. 10. The system of any of the preceding clauses, wherein the nuclear reactor includes a reactor vessel, a primary coolant loop at least partially disposed within the reactor vessel, and a primary heat exchanger in thermal communication with the primary coolant loop.

[0203] 46. 46. ​​The system of claim 45, wherein the primary heat exchanger is a sodium-salt heat exchanger.

[0204] 47. 46. ​​The system of clause 45, wherein the primary heat exchanger transfers thermal energy from the reactor core to a working fluid of the thermal energy storage system.

[0205] 48. 1. A system comprising: a nuclear reactor within a reactor site boundary, the reactor having a reactor vessel; a heat exchanger within the reactor vessel configured to thermally couple a primary coolant within the reactor vessel to a salt coolant of a coolant loop; a thermal energy storage system located outside the reactor boundary and configured to receive thermal energy from the salt coolant of the coolant loop; A system comprising:

[0206] 49. 49. The system of clause 48, further comprising a power generation system in thermal communication with said thermal energy storage system, said power generation system being located outside said reactor site boundary.

[0207] 50. 49. The system of claim 49, wherein the nuclear reactor has a first nameplate capacity and the power generation system has a second nameplate capacity, the second nameplate capacity being greater than the first nameplate capacity.

[0208] 51. 1. A system comprising: a nuclear reactor having a thermal power output; a power generation system having a thermal power input in thermal communication with the nuclear reactor; Including, 10. A system wherein the thermal power input is greater than the thermal power output.

[0209] 52. 52. The system of claim 51, further comprising a thermal storage system disposed between the nuclear reactor and the power generation system, the thermal storage system receiving thermal power from the nuclear reactor and supplying thermal power to the power generation system.

[0210] 53. 53. The system of clause 52, wherein the thermal storage system is sized to provide more thermal power than the nuclear reactor can provide.

[0211] 54. Furthermore, including the reactor site boundary, 52. The system of clause 51, wherein the reactor is located within the reactor site boundary.

[0212] 55. 55. The system of clause 54, wherein the power generation system is located outside the reactor boundary.

[0213] 56. 10. The system of any of the preceding clauses, including a primary heat exchanger, wherein the primary heat exchanger is a sodium-salt heat exchanger.

[0214] 57. 57. The system of clause 56, wherein the primary heat exchanger is located within a reactor vessel of the nuclear reactor.

[0215] 58. 58. The system of clause 57, wherein the first heat exchanger is in thermal communication with the thermal storage system.

[0216] 59. 53. The system of clause 52, further comprising a second nuclear reactor in thermal communication with the thermal storage system.

[0217] 60. 59. The system of claim 59, wherein the second reactor is a reactor of a different design than the first reactor.

[0218] 61. 53. The system of clause 52, further comprising a solar thermal plant in thermal communication with said thermal storage system.

[0219] 62. 53. The system of clause 52, further comprising a wind power plant in thermal communication with the thermal storage system.

[0220] 63. 10. The system of any of the preceding clauses, wherein the nuclear reactor is decoupled from the thermal storage system and the power generation system.

[0221] 64. 10. The system of any preceding clause, further comprising a hydrogen generator that receives thermal energy and generates hydrogen.

[0222] 65. 65. The system of claim 64, wherein the hydrogen generator comprises an electrolyzer.

[0223] 66. 66. The system of claim 65, wherein the hydrogen generator produces hydrogen via a high temperature electrolysis process.

[0224] 67. 65. The system of claim 64, wherein the hydrogen generator produces hydrogen via a steam reforming process on natural gas. [Brief explanation of the drawings]

[0225] [Figure 1] A typical nuclear power plant is shown. [Figure 2] 1 illustrates a nuclear heat plant decoupled from a power plant, according to an embodiment. [Figure 3] 1 illustrates a nuclear heat plant coupled to a thermal storage plant, according to an embodiment. [Figure 4]1 illustrates a nuclear heat plant coupled to a remote thermal storage plant with optional auxiliary thermal storage, according to an embodiment. [Figure 5] 1 illustrates a nuclear heat plant coupled to a remote thermal storage system coupled to an external load, according to an embodiment. [Figure 6] 1 illustrates exemplary industrial heating applications and the temperatures required. [Figure 7] 1 illustrates an energy system in which multiple heat sources share a common thermal storage and energy conversion system, according to an embodiment. [Figure 8] 1 illustrates an energy system in which multiple heat sources share a common thermal storage and energy conversion system with an auxiliary power system, according to an embodiment. [Figure 9] 1 illustrates a nuclear heat plant coupled to a remote heat storage system coupled to an external load and auxiliary heat utilization, according to an embodiment. [Figure 10] 1 illustrates a hybrid energy system in which multiple forms of thermal energy generators are coupled to a common thermal storage system and a common power conversion system, according to one embodiment. [Figure 11] 1 illustrates an energy system in which a nuclear block is decoupled from a power block by an integrated energy storage block, according to an embodiment.

Claims

1. 1. A system comprising: a nuclear reactor having a thermal power output; a power generation system having a thermal power input in thermal communication with the nuclear reactor; Including, the thermal power input is greater than the thermal power output; the thermal power output is the nameplate capacity of the nuclear reactor, and the thermal power input is the nameplate capacity of the power generation system; The system further includes a thermal storage system disposed between the nuclear reactor and the power generation system, the thermal storage system having a thermal energy capacity greater than the thermal power output.

2. The system described in claim 1, characterized in that the heat storage system receives first thermal power from the nuclear reactor and supplies second thermal power to the power generation system.

3. 3. The system of claim 2, wherein the second thermal power is greater than the first thermal power.

4. Furthermore, including the reactor site boundary, 10. The system of claim 1, wherein said nuclear reactor is located within said reactor boundary.

5. 5. The system of claim 4, wherein the power generation system is located outside the reactor site boundary.

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