Nuclear thermal power plant with load-following power generation

Abstract

The integrated energy system includes a nuclear thermal plant located at the reactor site. The nuclear thermal plant produces thermal energy that is transported to a thermal energy storage system located outside the reactor site. The thermal storage system is thermally coupled to a power generation system that is also remote from the reactor site. This arrangement isolates and decouples the nuclear thermal plant from the power generation system. The nuclear thermal plant can provide thermal energy above 800°C, which is stored in the thermal energy storage system until needed, such as for industrial heat, the power generation system, or other uses. The thermal storage system is source-forgiving, allowing one or more additional thermal energy generators, such as additional nuclear reactors, solar thermal plants, or other thermal energy generators, to be coupled to the common thermal storage system and power generation system.

Description

Detailed Description of the Invention

[0001] [Cross - Reference to Related Applications] This application claims the benefit of U.S. Provisional Application No. 62 / 833,623, filed Apr. 12, 2019, and U.S. Provisional Application No. 62 / 929,003, filed Oct. 31, 2019, under 35 U.S.C § 119(e). Both are entitled "NUCLEAR THERMAL PLANT by LOAD - FOLLOWING POWER GENERATION", and the disclosures of both are incorporated herein by reference in their entireties.

[0002] [Background] The field of the present disclosure relates to nuclear reactors, and more particularly to nuclear reactors for generating heat having improved safety and load - following capabilities.

[0003] Conventional methods and systems for generating power from nuclear reactors require that the nuclear reactor receive significant planning, construction, and regulatory approval for the nuclear island before startup. The nuclear reactor is connected to a power cycle for converting nuclear thermal energy into electricity and is typically converted by a steam turbine that uses water as the working fluid. Although nuclear reactors operating in this way have been around for decades, typical configurations have several drawbacks.

[0004] For example, a nuclear island, including the reactor area, fuel handling system, and energy conversion system, is typically operated at high temperatures and pressures, which requires large containment structures. Additionally, the structures located within the nuclear island must also be inspected and given nuclear approval by regulatory authorities in order to operate, which is a long - term and costly endeavor.

[0005] Furthermore, nuclear reactors are subject to errors in the rest of the plant such that a malfunctioning device can cause the automatic shutdown of the nuclear power plant. Finally, nuclear power plants are not designed for rapid changes in output and thus cannot efficiently follow the load demand from the power grid.

[0006] Nuclear power plants offer numerous and significant advantages compared to other forms of power generation, but improvements are desired that provide a safer, more flexible, and efficient system 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 one embodiment, a nuclear power plant can be reconfigured, relocated, and operated as a nuclear heat plant that offers numerous advantages. For example, the nuclear power plant can be reconfigured and operated to supply thermal energy, which can be transported to a heat storage system off-site. The heat 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 reactor from the rest of the plant that includes the energy conversion system.

[0008] For example, with fewer devices installed in the nuclear island, regulatory approval can be carried out much more efficiently. In some reactors, the coolant is supplied by a liquid metal such as sodium. When sodium encounters water, the resulting reaction is exothermic and energetic, and safety systems must be arranged to inhibit this reaction and contain it if it occurs. By locating the steam plant away from the reactor, the reactor is isolated from any water-containing systems that are typically used in conjunction with nuclear power plants.

[0009] In addition, multiple nuclear heat plants can be coupled to a shared heat storage system, which provides advantages in terms of cost and construction time, and also allows for easier maintenance since one or more reactors can be shut down without affecting the entire nuclear heat plant. The nuclear heat plant can supply more energy effectively during periods of high demand than when directly coupled to an energy conversion system.

[0010] The following description provides concepts that offer progressive possibilities for the economics of sodium reactor plants, as well as reactor plants using other fuels, coolants, and technologies. These advancements may result from reimagining technologies that mitigate cost and schedule uncertainties and expanding revenue streams, such as by supplying both electricity and heat to consumers. In addition to economic benefits, it is possible to ensure the ability to address policy issues (such as reliability of the power transmission grid, proliferation resistance of weapons, exportability, ease of on-site availability, etc.) and enable the realization of benefits.

[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 of exemplary embodiments and the accompanying drawings.

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

[0013] FIG. 2 shows a nuclear heat plant separated from a power generation plant according to an embodiment.

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

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

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

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

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

[0019] Figure 8 shows an energy system in which a plurality of heat sources share a common heat storage and energy conversion system with an auxiliary power system, according to an embodiment.

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

[0021] Figure 10 shows a hybrid energy system in which a plurality of forms of heat energy generators are coupled to a common heat storage system and a common power conversion system, according to an embodiment.

[0022] Figure 11 shows an energy system in which a nuclear block is separated from a 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 in accordance with the embodiments disclosed herein. The detailed description includes many specific embodiments, but these are provided by way of example only and should not be construed as limiting the scope of the invention disclosed herein.

[0024] The cost of nuclear power is important and worthy of attention, but the revenue side and policy side of nuclear power are equally worthy of focus. The cost of nuclear power is an important indicator in describing commercial attractiveness while entering a highly regulated commercialized market for base load power generation. Finding an approach to reduce regulatory burdens and expand commercial market opportunities is the key to progressive economic changes that increase revenue for a moderate cost increase. Enabling technical solutions to policy issues also has strategic value that is difficult to obtain in consideration of night-time construction costs. Utilizing attributes that are currently of low value, such as no CO2 emissions, along with the ability to integrate with an increasingly dynamic power grid will become more valuable in the coming decades.

[0025] In addition to the issue of operating costs for load following by nuclear energy, since the price of electricity varies daily like that of a "peaker" plant (e.g., a power plant that can only be operated when there is high demand or peak demand), base load power generation does not have the ability to follow revenue. To improve the competitiveness of nuclear power generation in a changing energy environment, technological and process innovations are needed to enable nuclear power generation to operate at full capacity and access opportunities for market arbitrage (straddle trading, arbitration) in addition to full output power generation. When the production cost of intermittent renewable energy is below the electricity price, nuclear power plants require alternative production means to serve as an alternative to only the electricity demand for load following. This basically requires 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 renewable energies is concentrated shaft power prior to electricity generation and heat output. By leveraging these differences, it is possible to define a competitive advantage either in more efficiently storing energy or creating another salable product during low-cost energy production. Many power generation facilities rely on the steam Rankine cycle to convert thermal energy into electricity. The conversion of shaft power to electricity in a rotating generator is highly efficient (98 - 99%), but the conversion from electricity to shaft power is slightly less efficient (~95%). Further losses occur with the step-up voltage for power transmission, power transmission through transmission lines, and the step-down voltage for local consumption. The exact losses from transmission to consumption are location- and distance-specific, but the overall estimated losses from power generation at a nuclear power plant to power consumption on-site are estimated at 2 - 4% in this example. The combined efficiency losses indicate that direct shaft power has an efficiency gain of 8 - 11% compared to electricity generation for shaft power at another location. As a result, there is a potential, competitive advantage adjudication trade-off between electricity generation and direct shaft power work with a sufficiently capable clutch-gear system. The clutch and gear system can fully or partially convert shaft power to work other than electricity generation. The challenges are the start / stop application up to the gigawatt scale and the mass flow rate of each product to support their huge workloads.

[0027] One such example is to use a compressed air energy storage (CAES) or liquefied air energy storage (LAES) device to supply the base load power demand and, in addition, supply shaft power to liquefy air, enabling a nuclear power plant to operate at full capacity during periods of low electricity prices (and thus low power demand). The cryogenic liquefied air stored at atmospheric pressure can later be boiled with nuclear waste heat to drive a power generation turbine. CAES and LAES are estimated to scale to GW-hr scale storage and represent an important capability for power management. The stored liquefied air can then drive the turbine at peak power prices, allowing the nuclear to be bypassed for base load price determination only. The scalability of CAES and LAES technologies and the technical maturity of large cryogenic storage tanks present an opportunity to combine centralized shaft power and waste heat for cryogenic cooling of nuclear power to boil liquefied air and drive a turbine. This combination of capabilities is more effective than the current proposed electric drive pump requirements and "thermal energy storage" needs of CAES and LAES technologies, giving the combined technology a competitive advantage compared to either technology alone. This technology, with appropriate development, could be retrofitted to the current U.S. nuclear fleet that produces 99 GW of power.

[0028] The most likely use of CAES and LAES is for energy production, but more selective distillation of liquefied compressed air could also provide high-quality gas streams as marketable products. As an example, it could be the sale of pure oxygen streams by temperature distillation for medical use or power generation for companies that wish to simplify carbon capture by removing the problems of NOX and SOX by simply burning natural gas and oxygen. This opens the possibility of co-locating natural gas power plants with CAES nuclear power plants to simplify carbon sequestration. The remaining distilled gas could, for example, be supplied for its low temperature value, specific gas value, or consumed by wind turbines to generate power.

[0029] Another similar use of shaft power in the United States is the liquefied natural gas (LNG) export market, which has seen continued increasing demand, 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 for the liquefaction process of 4100 kj / kg, approximately 230 GWh of energy per year is required to support the current liquefaction process. Nuclear power plants can play an important role in increasing LNG exports to other regions of the world through a combination of direct compression or CAES energy storage using chilled water CAES on one side of a heat exchanger and natural gas on the other side. In this combined system, natural gas is liquefied for storage or export, and compressed air boils to turn an electric turbine. In either case, air and natural gas can be brought into the power plant and easily processed, and is relatively suitable for "start-stop" operation to respond to load following.

[0030] Another example of fluid pump transportation is pumped-storage hydropower / aquifer recharge as a reasonable start / stop application. Assuming that market signals for large-scale pump transportation (pumping, pressurization) efforts and related pipelines will develop over the next decade, the efficiency improvement using direct shaft power for aquifer recharge could be more than 7 quads per year (i.e., 1 quad is 10 15 BTU, i.e., 1.055×10 18 Joules). Perhaps, water recycling efforts will reduce the pumping effort required, but will probably not eliminate the need for replacement water. Additionally, this pump transportation effort also serves as a huge "pumping" capacity that can run in reverse along the pipeline to supplement intermittent power supplies and recharge the regional aquifer.

[0031] As described above, centralized shaft power is just one of the characteristics of nuclear power compared to options such as sunlight, wind power, and other renewable power sources. In industrial processes that produce refined oil, coke, steel, chemicals, cement, etc., both energy and a specific temperature are required. This minimum temperature requirement for chemical processes to occur is an important differentiating factor in terms of which major energy source is the best. Although the major heat consumption is specific to a single market, the temperature requirements for a given process are universally necessary. There is a spectrum of temperature requirements for processes, but the main interesting temperatures seem to be 100 - 250°C, which is associated with the production of steam and hot water, the refining (petrochemical) process in the range of 250 - 550°C, and high-temperature processes for the production of cement, steel, and glass above 1000°C. Looking at the overall energy market, the oil refining industry consumes more than 6 quad per year, and the forest products industry consumes more than 3 quad per year.

[0032] Fossil fuels currently meet both the scale of energy demand and temperature. In a decarbonized energy world, the challenge is to find the best way to replace the usefulness and versatility of fossil fuels. In the case of wind power, solar power, and hydropower, a significant amount of energy is generated, but not a significant amount of high-quality heat. These energy sources must undergo another energy conversion to produce higher-quality process heat. The price determination of these energy sources needs to include additional processes such as hydrogen production by resistance heaters or blast furnaces. There may be additional energy storage requirements to achieve a high equipment utilization rate for operating industrial plants 24 hours a day, or to accept "lost opportunities" in low-utilization-rate plants.

[0033] Nuclear power plants have competed on price by competing with heat rather than electricity, based on $ / KWe converted to the required temperature against $ / MMBTU. One of the most obvious starting competition points is the direct generation and consumption of steam. Forest products consume 1.3 quad of steam annually, which is equivalent to more than 45 GWth of a nuclear power plant operating 24 hours a day simply for process steam. In the manufacture of forest products, part of the process generates wastes such as black liquor (e.g., the waste from the kraft process when digesting pulp into paper pulp and removing lignin, hemicellulose, and other extracts from wood to remove cellulose fibers), biomass, and other residual fuels, which are burned for process heating to generate steam. The remainder of the required fuel is currently supplemented by coal or natural gas. By using nuclear power to generate steam, 1330 TBtu (1.3 quad) of primary energy used in other high-temperature applications such as petroleum refining and cement applications is liberated. By utilizing nuclear thermal energy to provide high-quality process heat to the forestry industry, the recovered forest product energy, combined with the reserve energy, can supply the energy requirements (combined to less than 1 quad) for both cement and glass manufacturing in the United States. The combustion of forest products is considered carbon-neutral activity and thus enables the nuclear replacement of steam generation to directly support high-temperature processes. There is great flexibility in the fuel sources for cement manufacturing, but technological innovation will be needed to ensure that forestry fuel products can be transported and used in other major heat applications. Similar to forest products, the entire chemical manufacturing industry consumes 1.2 quad of steam that can be directly replaced by steam generated by nuclear power. However, this energy displacement does not completely liberate renewable fuel sources but 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 assist in the conversion to products.

[0034] Another use of nuclear-powered steam is in combination with a nuclear power plant that produces steam for hydrogen electrolysis while an intermittent power source produces inexpensive electricity, and the electricity when the intermittent power source is off. As the temperature of the steam increases, the power required to perform electrolysis becomes smaller. However, the improvement in power efficiency at higher temperatures may not be economically interesting in a world where peak intermittent power generation drives electricity costs "down to the meter level". If the cost of the electrolysis equipment can be inexpensively integrated into a steam bypass pipeline, the reactor could be partially or fully shifted to electrolysis easily during inexpensive electricity hours. This would allow the nuclear power plant to compete for heat production during low electricity prices and electricity during high electricity prices. The resulting hydrogen production should be regarded not only as an energy storage mechanism but also as a source for industrial heat demand above 1000 °C, such as for cement, iron, steel, glass, etc.

[0035] In the case of advanced reactors with higher outlet temperatures, more direct industrial process opportunities become available. For example, the higher reactor outlet temperature can be used as a preheater for other industrial processes or as the main heat source for chemical processes. In petroleum refining, there is a large energy demand in the distillation and cracking of hydrocarbons that requires over 6 quads of energy. Sodium-cooled reactors can serve as the main heat source for a number of low-temperature cracking processes, and reactor heat can also be "ramped up" to the required peak refinery temperature using electric heating or a small amount of fossil fuel. Many of the technical challenges in this case are to establish refinery technology that accepts temperatures and energy inputs other than oil, electricity, and steam, and to minimize the number of heat exchanger / loss values during heat exchange. One example would be an alternative to the salt / oil heat exchanger for the traditional combustion box for pyrolysis. Other types of advanced reactors, such as molten salt reactors, can be used to directly generate, for example, the required high-temperature industrial process heat.

[0036] In addition, there is also an opportunity for thermal energy storage in order to separate the heat production and heat utilization of a nuclear thermal power plant. It has been proposed to use the primary coolant of a nuclear thermal power plant to heat a large heat accumulator, such as a phase change salt, and pump it into a large tank. These large tanks of heated salt can then be used later to generate electricity, for example, by a steam Rankine cycle, or to supply process heat for a coating-based process. By separating the generation of heat from its direct utilization, the heat accumulator operates at full power and fills the high-temperature salt water tank, but serves as a flexible means of "load following" in electricity generation by generating electricity at more valuable times during peak demand or more traditional base load energy generation. This approach also enables a nuclear power plant to operate like a peaking plant for opportunities in price arbitrage trading, while still operating at full power. If the nuclear power plant, the primary coolant / salt heat exchanger, and the salt storage facility can be separated as not being safety important for the reactor, such that the construction and equipment regulations for power generation are the same as those for non-nuclear power plants, additional cost savings also exist. This enables typical commercial security protocols, operation and maintenance costs ("O&M"), and quality standards that can justify any heat exchanger or heat loss by pumping high-temperature salt out of the safe area of the nuclear power plant. Essentially, the power system for nuclear power plants can be built in an environment other than NQA1 (with associated maintenance work) to obtain commercially competitive construction from existing solar thermal salt power companies.

[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 solar-photovoltaic, in addition to the steam-electrolysis discussed earlier. An example of a high-temperature process is the copper-chlorine cycle. In this cycle, process heat at 400 - 500 °C is used to produce hydrogen and oxygen gases. The final step of the cycle uses ambient-temperature electrolysis to recycle all chemicals except the water that is converted to gas. This process represents an interesting opportunity to "follow the supply" of inexpensive electricity generated during peak wind and sunlight periods. By operating a higher-temperature nuclear heat plant non-stop to produce hydrogen and oxygen gases, the plant equipment and O&M costs are justified while filling the tanks with copper-chlorine reactants for electrolysis. When electricity becomes inexpensive, the tanks are converted back to the appropriate chemical precursors using ambient-temperature electrolysis and the cycle is started again. This process is mentally similar to filling the salt tanks with hot salt for later use, but more specifically it is tailored to the final chemical product. This example does not necessarily advocate for the copper-chlorine cycle, but the concept of following the supply of electricity is a different approach from energy storage for following demand. Also, this process allows most of the equipment of the nuclear power plant used for hydrogen production to be used only in some tanks and electrolysis equipment that are idle during normal operation.

[0038] These features and benefits, like many others, can be achieved by relocating nuclear power plants, which allows for the co-location of nuclear heat plants with industrial and chemical heat applications, reduces the installation area of the NQA1-certified area, and enables load-following capabilities 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 parts, namely, the nuclear island and the turbine island. The nuclear island has at its center a reactor region 102 that houses the reactor. The fuel handling area 104 is adjacent to the reactor region, and both buildings are typically within the containment area 106. The containment area 106 can include a containment enclosure structure that can be made of reinforced steel, concrete, or a combination of materials such as lead or materials forming an enclosing structure for housing (containing, confining, enclosing, encapsulating, inserting, surrounding) the reactor. Its design and function are to contain the leaking radioactive steam or gas, and it is often designed to contain the gas leaking at a pressure of 550 kPa or more. The containment structure is designed as the last line of defense against design basis accidents. The cost of constructing the containment structure is not only directly proportional to the size of the reactor but also based on the systems of the rest of the plant and the components that need to be housed therein. 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 area 106, is designed to provide a fuel replenishment capacity at a rate that maintains continuous reactor operation. Also, the fuel handling area 104 houses subcritical fuel outside the reactor core to prevent fuel damage and contamination. Further, the fuel handling area 104 can include devices for moving fuel pins and fuel assemblies, such as for reloading fuel into the reactor core.

[0041] In the reactor area and part of the nuclear island, a steam generator 108 is coupled. In some cases, the steam generator 108 is within the containment area 106 and supplies superheated steam to the steam turbine 110. The steam generator 108 receives the thermal output from the reactor and transfers thermal energy to a steam turbine 110 that converts steam energy into mechanical energy. In some facilities, radioactive water passes through the steam turbine 110 but must be kept within the radiologically controlled area of the nuclear power plant. The steam turbine 110 is then mechanically coupled to a generator 112 that converts the mechanical energy from the steam turbine 110 into electric power.

[0042] A fuel pin inspection area 114 may be present on site for performing post-irradiation examination ("PIE") and analysis. The fuel pin inspection area 114 is often adjacent to the fuel handling area 104 to share competing fuel handling equipment. The fuel pin inspection area 114 can further include a hot cell for accumulating and inspecting irradiated fuel pins.

[0043] As shown in FIG. 1, the containment area 106 may be required to encompass the reactor area 102, similar to the fuel handling area 104. In some cases, the building and associated equipment of the steam generator 108 are outside the containment area 106, but in many cases, it is required to be within the containment area 106. One or more coolant loops are used to transfer heat from the reactor area 102 through a heat exchanger to a coolant fluid, which not only cools the reactor core but also enables heat to be transported from outside the containment to the building of the steam generator 108. In many cases, the primary coolant loop receives heat from the reactor core by a primary heat exchanger and transfers the thermal energy to a secondary coolant loop by a secondary heat exchanger. In many cases, the coolant within the primary coolant loop becomes radioactive. Many currently used 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 when absorbing thermal energy from the reactor core and then transferring the thermal energy to the secondary loop.

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

[0045] In some examples, the primary and / or secondary coolant may be another material such as a molten metal. As an example, in some fast nuclear reactors, a molten metal such as liquid sodium is used as the coolant. In other examples, a molten salt may be used as the coolant. Both molten metals and molten salts have low vapor pressures even at high temperatures and can thus transfer heat at pressures lower than those at which water can do so at similar temperatures.

[0046] The nuclear power plant 100 is typically protected by a site boundary 120, which may include a security boundary such as a tall fence with laser wire. The nuclear power plant 100 and its associated buildings, structures, systems, pipes, etc. can be referred to as the reactor site within the reactor site boundary 120. Among other means, additional security measures such as gates across all access points, guards at access points, surveillance cameras, motion detectors, and / or electrified fences are typically used to protect the reactor site.

[0047] The nuclear power plant 100 is also required to have an Emergency Planning Zone (「EPZ」) that is needed to prepare for a major accident at the nuclear power plant. Often, the EPZ encompasses a radius of 10 miles 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 main buildings, together with the control room, constitute the nuclear island. It can be seen that, compared to the typical nuclear power plant shown in FIG. 1, the steam generator, steam turbine, generator, and fuel pin inspection area are no longer on the nuclear island. Rather, these components are installed away from the nuclear island. The illustrated reactor region 202 is configured as a nuclear heat plant 200 and is designed and operated to generate heat (in contrast to electricity in a typical nuclear power plant). In the illustrated configuration, the heat storage system 208 is remote from the nuclear island and receives thermal energy from the nuclear heat plant 200. It should be noted that the thermal energy generated by the nuclear heat plant 200 is transported away from the nuclear island, often beyond the site boundary 210 and even beyond the EPZ.

[0049] One direct advantage of this configuration is that the facilities for heat storage 208 and power generation 212 are outside the scope of nuclear regulation. This enables the nuclear heat plant 200 to be constructed and approved much more efficiently than is possible with the installation of a nuclear power plant.

[0050] The reactor as shown in FIG. 2 can be any suitable type of reactor. For example, the reactor can 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. The thermal energy generated by the reactor can be transferred to the heat storage system using an energy transfer system 214.

[0051] In certain embodiments, the nuclear reactor can utilize fuels that do not require heavy equipment for handling fuel, such as for refueling fuel pins or replenishing fuel to the nuclear reactor. Thus, in these embodiments, the fuel handling area 204 can be much smaller than that required to move fuel pins and fuel assemblies in and out of the nuclear reactor core. Such nuclear reactors can include, among others, pool-type nuclear reactors or molten salt nuclear reactors. One advantage of this type of nuclear reactor is that the fuel handling area 204 can be much smaller, and thus the nuclear island and / or the containment area 206 can be smaller than those typically required by nuclear reactors that utilize fuel pins and fuel assemblies and thus require heavy equipment for their handling and operation.

[0052] In certain embodiments, the nuclear reactor can include a nuclear reactor having a liquid coolant. For example, the liquid coolant of the nuclear reactor can include, but is not limited to, a liquid metal or a 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 can include a nuclear reactor having a pressurized gas coolant. For example, the pressurized gas coolant can include, but is not limited to, pressurized helium gas or pressurized carbon dioxide gas.

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

[0055] The thermal energy storage system 208 can include any suitable thermal energy storage plant, whether currently known or later developed. In certain embodiments, the thermal energy storage system can store thermal energy in the range of 500°C or higher. In one example, the thermal energy storage system stores energy at 550°C, 600°C, 700°C, 750°C or higher. In one example, the thermal energy storage system 208 is designed to store thermal energy at 1000°C or higher. In certain embodiments, the thermal energy storage system 208 has a plurality of thermal energy storage bodies and stores thermal energy at different temperatures.

[0056] The thermal energy 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 nuclear reactor primary coolant passes through the primary heat exchanger, transfers thermal energy from the nuclear 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 regarded as a secondary coolant loop designed to receive thermal energy from the primary coolant loop and transport the thermal energy to the thermal energy storage system 208.

[0057] For example, a first portion of the energy transfer system 214 may be in thermal communication with a part of the nuclear reactor primary coolant loop, and a second portion of the energy transfer system 214 may be in thermal communication with the thermal energy 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 together to supply heat from the nuclear reactor to the energy transfer system 214 and to the heat storage system 208. For example, a primary heat exchanger including a number of heat pipes can be used to thermally couple the primary heat exchange loop of the nuclear reactor to the energy transfer system 214. Also, a second heat exchanger that can include a plurality of heat pipes can be used to thermally couple the energy transfer system 214 to the heat storage system 208. In this way, the thermal energy generated by the nuclear reactor can be transferred to the heat storage system 208. The energy transfer system 214 can utilize a liquid metal, a salt, or some other working fluid to facilitate heat transport. Alternatively, the energy transfer system 214 can be in direct thermal communication with the storage medium of the heat storage system 208, such as where the storage medium of the heat storage system 208 can move into a first heat exchanger within the nuclear reactor vessel.

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

[0060] In some examples, the thermal energy storage system 208 has a greater thermal energy capacity than is designed to be output by the nuclear reactor's thermal power output. For example, the thermal energy storage system 208 may be designed to supply 1200 MWth of energy, while the nuclear reactor may be designed and operated to output 400 MWth of energy. Thereby, the thermal energy storage system 208 can store surplus energy in excess of the energy supplied by the nuclear reactor and supply this energy to the power plant 212 as needed. For example, when the load demand on the thermal energy storage system 208 is lower than the output of the nuclear reactor, the thermal energy storage system 208 is charged with additional thermal energy. During high demand times when the load demand on the thermal energy storage system 208 is greater than the output of the nuclear reactor, the thermal energy storage system 208 is discharged.

[0061] As further shown in FIG. 2, the power plant 212 is coupled to the thermal energy storage system 208. The power generation system 212 can be any power generation system 212 that is currently known or later developed. In one embodiment, the power generation system 212 receives thermal energy from the thermal energy storage system 208 and converts the thermal energy into electricity.

[0062] In some cases, the thermal energy can be passed through a steam generator to produce high-temperature and high-pressure steam, which can be used to drive a steam turbine. The steam turbine then drives a generator and converts the mechanical work of the steam turbine into electricity, which, as is well known, can be supplied to the power grid.

[0063] In other examples, the thermal energy from the thermal energy storage system 208 can be sent to a solid-state power generation device that directly converts heat 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-developed power plants that require heat for power generation.

[0064] The thermal energy storage system 208 is in thermal communication with the power generation system 212 via any suitable means. For example, an energy supply system 216 can be provided to supply thermal energy from the thermal energy 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 energy 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, including, 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.

[0065] The illustrated configuration and the application of the thermal energy storage system 208 enable the reactor to be decoupled from power conversion applications. This offers many advantages. For example, the reactor is no longer subject to transient phenomena from outside the site boundary 210 that could cause problems for the rest of the plant. These types of malfunctions can be handled without the need to shut down the reactor. In conventional nuclear power plants, plant transients lead to reactor problems, which are economic and safety concerns. These transients can be caused by malfunctions in components of the rest of the plant's system, such as a malfunctioning component of the steam generator, steam turbine, or some other auxiliary component that shuts down the reactor. For the nuclear heat plant 200, since the reactor is decoupled from the rest of the plant's system, these problems are no longer a concern. Any of the power generation system 212, the thermal energy storage system 208, or the reactor system can be safely shut down, for maintenance etc., without affecting the other systems.

[0066] For example, while the heat storage system 208 can continue to supply thermal energy to the power generation system 212 that continues to be powered, the reactor system can be shut down and taken offline. Similarly, while the reactor system continues to generate thermal energy and essentially continues to charge the heat storage system 208 with heat, the power generation system 212 can be shut down or operated with a reduced output. In certain embodiments, the reactor system is operated at full capacity and the thermal energy is transferred to a heat storage system 208 that 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 seasons, while the reactor system can continue to operate continuously at full capacity regardless of the load.

[0067] Furthermore, in a nuclear thermal power plant that utilizes a sodium-cooled reactor, by moving the steam generation system to a remote location as described, the water from the steam cycle has little or no risk of interacting with the sodium used in the reactor, thus increasing safety.

[0068] In a traditional nuclear power plant, the intermediate coolant loop transfers thermal energy from the primary coolant loop of the reactor to the steam generator and, being in close proximity to the reactor core, is subject to radiation exposure and must be designed to withstand this type of radiation that degrades construction materials. For example, certain metals can become brittle due to radiation hardening, which reduces toughness and poses a risk of brittle fracture. In the described configuration, the intermediate coolant loop is moved away from the reactor (or completely eliminated) and can be made of materials that are easier to supply and manufacture and are therefore less expensive and more readily available.

[0069] As shown, the thermal energy storage system 208 and the power generation system 212 are outside the site boundary 210 of the nuclear thermal power plant 200. Specifically, the nuclear thermal power plant 200 is within the site boundary 210 such as a security fence, and all devices within the site boundary are subject to strict nuclear regulations. When systems of the rest of the plant, such as the thermal energy storage system 208 and the power generation system 212, are located away outside the site boundary 210, the regulations for these systems are significantly reduced, and construction, licensing, and operation become much more efficient. These systems of the rest of the plant may further be arranged outside the EPZ.

[0070] In one embodiment, the nuclear thermal power plant 200 can include a reactor that is inherently safe, and the EPZ can be sized to coincide with the site boundary 210. In other examples, the EPZ can be sized to be within the site boundary 210. In either case, arranging systems of the rest of the plant outside the reactor site boundary 210 has numerous advantages in terms of safety, efficiency, and the speed of construction and licensing.

[0071] Furthermore, in the described configuration, the nuclear thermal power plant 200 is load-following capable. Load-following is the concept of adjusting power output as the electricity demand varies throughout the day. Traditional nuclear power plants typically operate at full output all the time and generally do not vary their output power. In the described configuration, the nuclear thermal power plant 200 can operate at full output designed to meet the base load requirements of the power grid. The base load of the power grid is the minimum level of demand over a certain period. This demand can be met by continuous power plants, dispatchable power 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 varies throughout the day, which can be met by dispatchable power generation that can be quickly turned up or down, such as load-following power plants, peaking power plants, or energy storage.

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

[0073] Furthermore, since the heat storage system can be made larger than the size configured to be supplied by the nuclear heat plant 200, the nuclear heat plant 200 can "charge" (load) (charge) the heat storage system during periods of non-peak electrical demand. In many load-following power plants, the plant is operated between day and evening and operates in direct response to changing power demands. The power plant can stop in the evening or at night when demand is low and then start 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 for power generation or for some other purpose. In some examples, the nuclear heat plant 200 can generate less thermal energy than required to meet peak load demand, but since it can charge the heat storage during off-peak usage times, the overall energy output from the nuclear heat plant 200 can supply base load and peak load demands over time.

[0074] In other examples, the nuclear heat plant 200 can produce more energy than required to meet base load demand. For example, the nuclear heat plant 200 can produce surplus thermal energy to meet peak load demand in addition to sufficient thermal energy used to meet base load demand, and can also supply additional thermal energy for other industrial purposes.

[0075] Referring to FIG. 3, a nuclear power thermal plant 200 including a heat generating reactor 302 is shown. The reactor 302 is in thermal communication with a heat storage system 304. The heat storage system 304 is in thermal communication with an energy conversion system 306 that communicates with an external load 308.

[0076] The heat generating reactor 302 can be any suitable type of reactor known currently or developed in the future, such as a fission reactor or a fusion reactor. Some examples of 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 reactors. Further, the heat generating reactor 302 can comprise an atomic reactor of any suitable size, such as a small modular reactor, a micro reactor, or even a gigawatt size reactor or larger. Further, one or more reactors (which can be of the same type or of different types and sizes) can be utilized in an integrated energy conversion system.

[0077] The reactor site boundary 310 is a physical barrier surrounding the nuclear power thermal plant 200 and is designed to safeguard the reactor 302. In many cases, the site boundary 310 surrounds a nuclear island that can be made much smaller than a typical nuclear power thermal plant as previously described in conjunction with the above embodiments. The heat storage system 304 is located outside the reactor site boundary 310. As described, the heat storage system 304 can be any suitable type of heat storage system 304 and can utilize any suitable type of heat storage medium. For example, the heat storage medium can be a eutectic solution, a phase change material, a miscibility gap alloy, a mixture of metals (e.g., AlSi 12) It can include a cement-based material, molten salts (such as 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 one example, the heat storage medium is also used as the heat transfer fluid in the energy transfer system 312 and / or the energy supply system 314. In this way, 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 heat storage medium of the heat storage system 304. Similarly, in one example, the energy supply system 314 may use the same heat transfer fluid as the heat storage medium of the heat storage system 304. In some cases, the heat storage system 304 may be in direct fluid contact with the energy supply system 314.

[0079] The heat storage system 304 is in thermal communication with the nuclear reactor 302 by means of an energy transfer system 312 that can be thermally coupled to the nuclear reactor 302 and the heat storage system 304 by a heat exchanger. The energy transfer system 312 typically transfers thermal energy to the heat storage system 304 via an insulated conduit, where the thermal energy is stored until it is needed.

[0080] The heat storage system 304 is in thermal communication with the energy conversion system 306 by means of an energy supply system 314 or the like. The energy conversion system 306 may be of any suitable type of currently known or later developed technology that can convert thermal energy into another form of useful energy. In one example, the energy conversion system 306 utilizes a steam turbine that can operate in a Rankine cycle to convert steam into mechanical work. In many cases, the steam is sent through a steam turbine that rotates the shaft of a generator to produce electricity.

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

[0082] The energy conversion system 306 can be coupled to the external load 308 by an energy transmission system 316. The external load may be a public power grid. The energy conversion system 306 can send the generated power to the power grid by means such as high-voltage transmission lines that carry the power from the energy conversion system to the demand center. In particular, the energy conversion system 306 is remote from the nuclear reactor 302 and is often outside the nuclear reactor site boundary 310 and often also outside the EPZ. As described, the nuclear reactor 302 is separated from the energy conversion system 306, and any failure in the energy conversion system 306 does not negatively affect the nuclear reactor 302, nor vice versa. In fact, even when the nuclear reactor 302 is shut down, for example, for maintenance or refueling, the thermal energy storage system 304 can continue to supply thermal energy to the energy conversion system 306 to supply power to the external load.

[0083] The relatively low cost of the thermal energy storage system 304 for the nuclear thermal power plant 200 is advantageous for scaling up the thermal energy storage system 304 and scaling down the nuclear thermal power plant 200. Further, when utilizing low-pressure heat transport (e.g., molten salt as the heat transport medium), the relatively high-cost energy conversion device 306 can be installed remotely from the nuclear thermal power plant 200. In this case, this conversion device can be constructed more efficiently and without the regulations that would be required if it were built on the reactor site. As used in this disclosure, the term "low pressure" is used to indicate a pressure of less than about 3.5 MPa.

[0084] In addition, when there is no high-pressure system (e.g., greater than about 3.5 MPa) coupled to the reactor 302, the EPZ can be minimized and the heat transport distance can be shortened. In some examples, the thermal energy storage system 304 may be installed in a location adjacent to but outside the site boundary 310 of the reactor site. This keeps the thermal energy storage system 304 and the energy conversion system 306 outside the reactor site boundary 310 and outside the scope of nuclear regulation while minimizing the heat transport distance.

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

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

[0087] The auxiliary heat storage 402 may be installed outside the reactor site boundary 310 as shown, or in some cases, may be installed within the reactor site boundary 310. In one embodiment, its function is to control the return to the reactor 302 and the core inlet fluid temperature. The actual T in predicted T in If there is a difference between and, 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 being higher than the predicted inlet temperature.

[0088] The auxiliary heat 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 heat storage 402 can be in thermal communication with the primary coolant loop within the reactor vessel. When the primary coolant fluid has a temperature different from the predicted T in the auxiliary heat 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 working fluid of the auxiliary heat storage, the effect is for the primary coolant to reach thermal equilibrium with the auxiliary heat storage fluid. By controlling the primary coolant temperature, the reactivity within the core of the reactor is stabilized and any natural fluctuations are smoothed.

[0089] In one example, the auxiliary heat 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 heat storage 402. In other examples, the auxiliary heat storage 402 is in thermal communication with the heat storage system 304, and a portion of the thermal energy from the heat storage system 304 is transferred to the auxiliary heat storage 402 for use in adjusting the reactor core inlet temperature.

[0090] One skilled in the art will readily understand how to put these various systems in thermal communication with each other and how to use these various systems to adjust the core inlet temperature.

[0091] Referring to FIG. 5, a nuclear thermal power plant 500 is shown that is substantially as described above. In particular, in some reactor designs, it is not necessary to rely on heavy fuel assembly handling devices. For example, in a pool-type reactor such as a molten salt reactor, 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 breeder and burner 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 can be much smaller and may only include the reactor and smaller subsystems of the reactor. This results in a significantly smaller containment area 206, which leads to lower costs for construction, licensing, and operation.

[0092] In addition, the smaller containment area 206 results in a smaller installation area for the site boundary 310. Furthermore, in an inherently safe reactor design, the site boundary 210 can be minimized and the EPZ can also be minimized. In some cases, the EPZ boundary coincides with the reactor site boundary 210, or in some cases, the EPZ is within the site boundary 210. This allows the heat storage system 208 and / or the power generation system 212 to be located outside the site boundary 210 while being located relatively close to the site boundary 210 to reduce the heat transfer distance of the energy transfer system 214.

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

[0094] The uses of industrial heat 512 are diverse and require heat at various temperatures. Industrial heat applications can include fluid heating for food preparation, chemical manufacturing, reforming, distillation, hydrogenation, etc., and require temperatures in the range of about 110°C to about 460°C. Similarly, curing and forming processes for coating, polymer manufacturing, enameling, extrusion, etc. require heat in the range of about 140°C to about 650°C. Other processes include those such as iron formation, smelting and steelmaking, and the manufacture of plastics and rubber. This industrial heat can be supplied, as needed, by the thermal energy storage system 208 in the quality and quantity according to the specific requirements of the industrial heat 512.

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

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

[0097] In one embodiment, the thermal energy storage system 208 can supply thermal energy to all required loads simultaneously. This can be achieved by scaling the thermal energy storage to a size that can supply the thermodynamic 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 power generation 212 such as for household use increases during the day and decreases at night. Therefore, the thermal energy storage system 208 can be sized and configured to supply all the requirements of the required load 510.

[0098] The thermal energy storage system 208 can include a plurality of storage facilities linked to each other. The plurality of storage facilities can include the same or different thermal energy storage media and can be maintained at different temperatures more suitable for different thermal loads. For example, some industrial heat 512 applications require temperatures above 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 that require lower temperatures. Of course, the individual storage facilities can utilize different thermal energy storage media that are specially designed to operate within the desired temperature range.

[0099] As an example, the high-temperature storage facility may utilize molten salt, which may be formulated to be thermally stable up to 1000°C or more, as the thermal energy storage media. The low-temperature storage facility can utilize water as the thermal energy storage media due to its high heat capacity (about 4.2 J / (cm 3 ·K)).

[0100] Figure 6 shows various industrial heat applications for which a thermal energy storage system can supply the required heat energy. As shown, district heating requires a temperature of about 50°C. This can be supplied by a thermal energy storage system having a heat storage medium that is stable at about 50°C to compensate for the efficiency of heat transfer, the heat storage medium can be maintained at a temperature higher than the required temperature, and the heat exchanger can be in thermal communication with a 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 of the reactors operating today are operating at temperatures in the lower half of the figure, i.e., below about 300°C. These reactors are thought to be able to store thermal energy at temperatures up to about 300°C and are suitable for many lower temperature heat load applications, including power generation.

[0102] However, for higher temperature heat 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 about 500°C - 550°C, which are suitable for supplying thermal energy up to the operating temperature. Other reactors are designed to be able to operate at 750°C - 800°C and can provide heat in this range suitable for higher temperature industrial use. Still other reactors can operate at temperatures above 1000°C and are suitable for supplying very high heat for industrial purposes. Fusion reactors, which are promised to operate at hundreds of millions of degrees Celsius, can supply even higher thermal energy than fission reactors.

[0103] Referring to FIG. 7, an integrated energy system 700 is shown, where a thermal energy storage system 702 is supplied with thermal energy from various heat sources. The thermal energy storage system 702 can be substantially the same as those described above in this specification. 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 using existing nuclear reactor technology at that time. The thermal energy storage system 702 can be coupled to an energy conversion system 710 that converts thermal energy into electricity and supplies the electricity to an external load, etc.

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

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

[0106] In many examples, multiple reactors can be constructed such that each reactor has its own reactor vessel, head, and site boundary, and all that extends beyond the site boundary can be made common to the multiple reactors. Of course, the reactors can be coupled to the thermal energy storage system 702 using pipes and valves. The energy supply system can use a common or different heat transfer medium to couple the reactors to the thermal energy storage system 702. By utilizing common components of the rest of the plant, such as a common thermal energy storage system 702, a common steam plant, common heat transport, and a common energy conversion system 710, efficiency is improved when scaling the size of the thermal energy storage system 702 compared to building separate nuclear power plants for supplying power, each having its own requirements for the rest of the plant.

[0107] Providing multiple reactors coupled to a common thermal energy storage system 702 provides the additional benefit of ease of reactor maintenance. One reactor can be taken offline for maintenance or refueling, etc., without shutting down the entire system. In some cases, one or more thermal energy generation systems (e.g., reactors, wind energy system 712, solar thermal energy system 714, geothermal systems, 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 remainder of the apparatus or interrupting the supply of energy to the external load 716.

[0108] In one example, the heat transfer fluid is perhaps molten salt throughout the entire energy system, except possibly the reactor core, and any of a number of coolants can be used. For example, the energy transfer system 214 that carries thermal energy from the nuclear thermal 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 molten salt, which may be the same salt as the working fluid of the energy transfer system 214 or a different formulation specific to its intended use. Further, the energy supply system 216 that transfers heat from the thermal energy storage system 702 to the energy conversion system 710 can also be molten salt. Of course, the molten salts used throughout the system may be the same salt or may have different formulations specific to their intended use.

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

[0110] In addition, other forms of thermal energy may be coupled to a thermal energy storage system such as solar thermal energy 714 or wind energy 712. In many cases, the thermal energy storage system 702 is tolerant with respect to the thermal energy source and can be coupled to a number of 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] FIG. 8 shows an exemplary energy system 800 in which a number of thermal energy sources are thermally coupled to a thermal energy storage system 702. The thermal energy source can be any one or more of a number of thermal energy systems such as a nuclear reactor thermal plant 704, a solar thermal plant 714, a wind energy plant 712, or other types of thermal energy generating plants, or any combination of thermal energy generating plants.

[0112] The thermal energy plant supplies thermal energy to a thermal energy storage system 702 that stores thermal energy by any suitable means such as a eutectic solution, a phase change material, a miscibility gap alloy, a mixture of metals, a cement-based material, a molten salt (e.g., a chloride salt, sodium nitrate, potassium nitrate, calcium nitrate, NaKMg, or NaKMg-Cl, etc.), solid or molten silicon, or a combination of these or other materials. In certain 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 generating plants. In some cases, the thermal energy transfer fluid is the same as the heat storage medium and is in fluid communication therewith. In this example, the intermediate heat transfer loop may optionally be omitted, and the heat storage medium can receive thermal energy directly from the thermal energy generating plant via a single heat transfer loop. The thermal energy plant can be in thermal communication with the thermal energy storage system 702 via one or more heat exchangers, but in certain 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 examples, this allows for adding or removing multiple thermal energy sources from the system 800 as needed.

[0113] In one embodiment, 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, and the auxiliary power system 802 uses that thermal energy to generate power, such as to supply electricity to one or more reactors 704, 706, 708. In some cases, the auxiliary power system 802 can supply blackstart capabilities to one or more reactors. This can provide dedicated power to the reactors when starting them, even in the event of a power outage or when electrical power from the power grid is unavailable. This also further isolates the reactors from the rest of the plant and from the power grid. Of course, the auxiliary power system 802 can supply backup power to any of a thermal energy generation plant, the thermal energy storage system 702, or any other system that benefits from uninterruptible backup power.

[0114] The thermal energy storage system 702 can be thermally coupled to an energy conversion system 710 that can generate energy for an external load as described above. Often, the external load 716 requires either thermal energy or electrical power, either of which can 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 can supply compressed and heated gas directly to a turbine, eliminating the steam generator typically used in a turbine power plant.

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

[0116] FIG. 9 shows an embodiment of an integrated energy system 900, in which a nuclear heat plant 200 supplies thermal energy to a heat storage system. Although 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. Next, the thermal energy storage system 702 supplies thermal energy to one or more loads 510 that can include loads for power generation 212, district heating 514, or industrial heat 512. In some cases, the load 510 may be relatively low over several days or weeks, and the thermal energy storage system 702 may 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 sources. Thus, the thermal energy generated by the thermal energy generating plant can be transferred to some other auxiliary heat utilization 902 that results in a benefit. In some cases, excess heat is released to the atmosphere, but in some cases, excess heat that exceeds what the heat storage system can receive can be used for other processes, such as, for example, water desalination or hydrogen production. Of course, the auxiliary heat utilization 902 can be supplied with thermal energy even when the heat storage system is not saturated. For example, the thermal energy from the thermal energy source may be supplied to the thermal energy storage system 702 and at the same time used for the auxiliary heat utilization 902.

[0117] These auxiliary heat utilizations 902 can receive a portion of the thermal energy before the thermal energy is supplied to the thermal energy storage system 702, or these auxiliary heat utilizations 902 can selectively receive all of the generated thermal energy if, for example, the heat storage system is full, or if the auxiliary heat utilization 902 is considered a higher and better purpose for the thermal energy than storing the thermal energy for later use.

[0118] In one embodiment, the thermal energy storage system 702 is located at a height above the power generation system 212. For example, the thermal energy storage system 702 may be constructed on a hill such that it is at a higher elevation than the power generation plant 212. This arrangement utilizes a composite energy storage mode by combining both thermal energy and the pressure due to gravity on the downstream system due to the height change. The composite 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 to handle peak loads and are selected to meet peak load demands by pumping the working fluid through the turbine system at a higher volume per unit time. By relying on gravity, the system can send additional heat through the steam generator and then to a cold storage tank. In one embodiment, 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 one embodiment, an existing storage site may be suitable for constructing a nuclear thermal power plant to be coupled to a heat storage system. There are currently numerous reactor sites that are no longer in operation or are scheduled to be decommissioned and taken out of service. These locations can be referred to as brownfield sites (redevelopment sites, existing industrial land), which is a nomenclature defined by the Environmental Protection Agency as real estate where expansion, reuse, or development can be complicated by the presence or potential presence of hazardous substances, contaminants, or pollutants. A decommissioned reactor site is a type of physical site that falls within the definition of a brownfield site.

[0120] However, nuclear reactor brownfield sites offer several advantages for the systems and methods disclosed or described herein. For example, nuclear reactor brownfield sites have existing civil work structures in place, such as roads, utilities (e.g., power lines, sewers, water mains, etc.), site boundary security, containment buildings, pipes, valves, auxiliary buildings, and the like. Many of these structures can be reused in a nuclear thermal power plant, thus significantly reducing the time and cost required for the construction and commissioning of a nuclear thermal power 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 would be required for a new generation of nuclear thermal power plants, and many of the new generation of nuclear thermal power plants operate at relatively low pressures compared to LWRs. The thermal energy storage system 702 can be located at a location remote from the nuclear reactor brownfield site and thermally coupled to the nuclear thermal power plant as described herein, such as via a heat transfer fluid loop. A passage can be made within the containment structure so that the heat transfer medium can exit the containment structure and send thermal energy to a thermal energy storage system 702 located at a location remote from the reactor site.

[0122] Existing containment structures can be configured to house one, two, or more nuclear thermal power plants. For example, in a single containment structure, multiple nuclear reactors can be constructed that share the containment structure, the fuel handling system, and other components. The containment structure may be divided into two or more reactor chambers to house multiple nuclear reactors and their associated support equipment. Two or more nuclear reactors can share, among other things, the fuel storage area, subsystems, the reactor core fuel supply / fuel removal system, and the fuel reprocessing system.

[0123] In some cases, it may be desirable to operate the reactor at full power. The systems and methods described herein enable the reactor to be maintained at continuous full power by disconnecting the reactor from the thermal energy storage and power generation systems. The reactor can continuously supply thermal energy to the thermal energy storage system, which can be sized to store and supply energy greater than that which the reactor can supply. Thus, the reactor can slowly "charge" the thermal energy storage system over time. If the reactor generates excess heat that the thermal energy storage system cannot receive, the excess heat may be transferred 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 released to the atmosphere.

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

[0125] The traditional use of nuclear power plants is for electricity generation. However, many of the newer Generation IV nuclear power plants are designed to have an outlet temperature exceeding 500 °C, which is significantly higher than the outlet temperature of light water reactors (LWRs). Thus, the potential applicability of this high-quality heat extends far beyond electricity generation. In the illustrated structure, the reactor 200 is used as a heat source that is sent to a separate thermal energy storage system 702 located outside the reactor site boundary 210. In combination with the proliferation resistance characteristics of the newer reactors, in addition to being carbon-free or at least having low carbon emissions, the structure of this integrated energy system 1000 enables (1) reduction of reactor and overall system costs, (2) enabling flexible power demand (load) following and “profit following” in the power grid, with greater penetration of renewable energy, (3) supplying high-temperature process heat at a cost competitive with natural gas, which is not currently possible with LWRs, and (4) enabling hydrogen production by high-temperature electrolysis, among many beneficial features.

[0126] These capabilities enable dramatic carbon reduction in industrial processes and the transportation sector, which currently account for approximately 75% of the world's greenhouse gas emissions.

[0127] One of the current obstacles faced by nuclear power plants is the upfront investment in construction and licensing costs associated with the construction and startup of nuclear power plants. One of the major cost factors in nuclear power plant construction is not the nuclear technology itself, but rather the cost of large-scale construction projects regulated by strict nuclear standards. Therefore, one of the biggest things that promises capital cost reduction will turn out to be not necessarily the technological progress of the reactor itself, but the plant design. As described herein, by significantly simplifying and reducing the scope and complexity of construction projects within the reactor site, the major cost factors associated with building a typical nuclear power plant are dramatically reduced. In various embodiments of the structures described herein, the scope of nuclear power plant and reactor construction projects is reduced to their most basic form. The simplified reactor becomes a producer of thermal energy, which is herein referred to as a nuclear thermal power plant.

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

[0129] Molten salt thermal energy storage systems are relatively inexpensive and are often an order of magnitude less expensive than battery storage and have achieved commercial readiness on the GWh scale. Appropriate thermal energy storage systems are currently being used in support of the concentrating solar power industry. Furthermore, due to the excellent safety advantages of the advanced reactors described herein, a very small EPZ is possible, which allows for a closer placement of these reactors to the heat consumers.

[0130] The integrated energy system described also addresses another challenge faced by nuclear power in current and future electricity markets. For example, as the proportion of electricity generated by intermittent renewable energy sources increases, there are significant fluctuations in power supply, typically between 9 am and 4 pm, with overproduction, as solar energy drives electricity prices very low, or even into negative territory. Current nuclear power plants typically have limited flexibility in rapid load following and are in some cases driven to maintain a relatively high capacity factor to achieve a low levelized cost of electricity (LCOE). Thus, even if nuclear power plants could adapt to daily varying electricity demand, their LCOE would increase, making it difficult to compete with alternative technologies. Salt thermal energy storage enables many types of nuclear thermal power plants to operate at 100% (or very close to it) capacity factor, storing energy in a thermal energy storage tank, such as a salt tank, and selling electricity during periods of high and expensive demand.

[0131] An important consideration in reducing greenhouse gas emissions is the expansion of decarbonization to other industrial processes. Energy consumption in this sector is predominantly in the form of heat and oil and chemicals are the major consumers. The integrated energy system described herein, having a high outlet temperature of about 510 °C to 540 °C or more and a heat storage medium compatible with these temperatures, provides opportunities to supply heat to a number of consumers up to about 500 °C, such as oil refineries, various chemical plants, soda ash production plants, pulp and paper plants, food processing plants, etc. There is also great potential for combined heat and power generation plants that produce both heat and electricity.

[0132] The transportation sector accounts for the second-largest share of the world's energy consumption after industrial manufacturing. Until recently, transportation was carried out only by gasoline fuel, and clean nuclear energy was not involved in this sector. This is changing with the recent advent of hydrogen-powered, battery- and fuel-cell-driven electric vehicles. The integrated energy system as described herein can provide both of these products without carbon, having a significant impact on the decarbonization of the transportation sector.

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

[0134] In some embodiments, the nuclear thermal plant and integrated energy system can be coupled, either solely or in part, to a hydrogen production plant and can use an electrolysis process that utilizes electricity to split water into hydrogen and oxygen. In one example, the integrated energy system can supply thermal power to the generated steam for use in the steam reforming of natural gas processes. In some cases, the high-temperature electrolysis process is a process in which a large amount of the electrolysis energy can be supplied by heat, thereby reducing the amount of electrical energy and thus the cost of producing hydrogen. In some cases, the high-temperature electrolysis process utilizes thermal energy having a temperature of about 800° C., which can be supplied by an integrated energy system as described herein.

[0135] FIG. 11 shows 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 is then in communication with a power block 1106. The power block 1106 can be in communication with an external load 1108. According to one embodiment, the nuclear block 1102 includes one or more nuclear reactors, such as a nuclear thermal power plant, having a reactor site boundary 1110 surrounding the nuclear island as described herein. One or more nuclear thermal power plants may be included as part of the nuclear block 1102, or one or more nuclear thermal power plants may be coupled to the integrated energy storage block 1104 and maintain their own separate reactor site boundary 1110. The integrated energy storage block 1104, also referred to herein as a heat storage system or a thermal energy storage system, may be composed of any suitable heat storage as described herein, and by way of example, may include a salt tank that depends on a phase change material that stores thermal energy at a stable temperature to receive thermal energy from the nuclear block. The integrated energy storage block 1104, which is also referred to herein as a heat storage system or a thermal energy storage system, is separated from the nuclear block 1102 by a boundary 1112 that may be defined by the reactor site boundary 1110. In some examples, the primary communication (transfer) between the nuclear block 1102 and the integrated energy storage block 1104 is one or more heat exchangers that transmit 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 effected by one or more heat exchangers configured to transmit thermal energy from the integrated energy storage block 1104 to the power block 1106. The power block 1106 may, for example, convert thermal energy into electrical power, which may be performed by a turbine such as a steam turbine, or some other type of system for converting thermal energy into electrical energy. The power block 1106 can utilize the thermal energy to generate electricity and transmit it, for example, to an external load 1108 such as a power grid.

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

[0138] According to some embodiments, the coal, the power block of the remainder of the plant (e.g., everything downstream of the boiler), along with the associated pipes, instrumentation and controls, includes equipment such as boiler drums, pendant superheaters, high-pressure turbines, reheaters, intermediate-pressure turbines, low-pressure turbines, condensers, feed pumps, deaerators, feed heaters, economizers, cooling towers, generators, transformers, and power transmission systems. These orphan assets are tolerant with respect to a source of thermal energy that can be supplied by an integrated energy storage block 1104 (e.g., a thermal energy storage system) as described herein.

[0139] The integrated energy storage block 1104 can receive thermal energy from any of a number of thermal energy sources, such as one or more nuclear thermal power plants, solar thermal energy, geothermal energy, wind thermal energy, wave energy, or any other suitable generator of thermal energy. According to one embodiment, the integrated energy storage block 1104 enables the combination of any form of thermal energy to be used with any form of power block 1106, providing the additional advantage of decoupling the nuclear block 1102 from the power block 1106.

[0140] This structure offers many advantages. As an example, there is a regulatory separation from the nuclear power block 1102 and all the devices downstream of the integrated energy storage block 1104, providing flexibility when adapting the nuclear power block 1102 to the power block 1106. For example, the nuclear power block 1102 does not need to be compatible with the power block 1106 in terms of power output. The nuclear power block 1102 operates at full output, transmitting thermal energy to the integrated energy storage block 1104, which can then supply thermal energy to drive the turbine of the power block 1106 in any suitable way. Thus, the operation of the power block 1106 is completely independent of the operation of the nuclear power block 1102.

[0141] According to an embodiment, the nuclear power block 1102 can operate at 100% capacity, but since the nuclear power block 1102 is disconnected from the power block 1106 by the integrated energy storage block 1104, the power block 1106 can fully follow the power demand.

[0142] The described structure also brings advantages in design efficiency. No longer is it necessary to adapt a nuclear reactor to a specific power block 1106. A general nuclear reactor can be adapted to a general power block, eliminating the need for new nuclear reactor development to adapt power to each arbitrary power block. A general nuclear reactor refers to a nuclear reactor of any design and power output. A general power block refers to a thermal-to-electric conversion system of any design, size, type, and power output, including, for example, a steam generator.

[0143] In one embodiment, the integrated energy storage block 1104 is designed to receive the output of the nuclear power block 1102 and supply thermal energy in accordance with the requirements of the power block 1106. In one embodiment, the described structure enables adaptation of a single reactor design or a combination of multiple reactor designs to the power block 1106. For example, if the power block requires 1600 MWth of steam for a turbine, that requirement can be met by, for example, one 1600 MWth reactor, two 800 MWth reactors, one 1200 MWth reactor and one 400 MWth reactor, etc. In some examples, the integrated energy block 1104 acts as a power aggregator from one or more reactor designs, and thus, by relying on the integrated energy block 1104 as a buffer, enables flexibility, scalability, and temporal independence in the connection of the power block 1106 to one or more reactors. This further enables the nuclear power block 1102 and the power block 1106 to be completely decoupled and independent from a design, construction, and operation perspective. A further advantage is that this structure enables the use of a single reactor design, such as a 400 MWth plant, in combination with multiple types of power blocks (e.g., 400 MWth, 800 MWth, 1200 MWth, 1600 MWth, 2000 MWth, 2400 MWth, etc.). In one embodiment, there may be a true mismatch between the nuclear power block 1102 and the power block 1106. For example, a reactor block 1102 that outputs 1600 MWth may be compatible with a power block 1106 of 1500 MWth. In other words, the nuclear power block 1102 can have a thermodynamic output, and the power block 1106 can have a thermodynamic input that is greater than or less than the thermodynamic output of the nuclear power block 1102. Stated another way, the reactor block 1102 can have a nameplate capacity that is different from the nameplate capacity of the power block 1106. As used herein, the nameplate capacity is the full-load sustained output of the facility.The nameplate capacity is typically a number registered with a regulatory agency to classify the power output of a plant and is usually measured in watts, megawatts, or gigawatts. The nameplate capacity may be used to refer to the power input (the power being input) to power block 1106 when used to describe power block 1106, which can be converted to power when power block 1106 operates at full output.

[0144] This type of mismatch can be addressed by the methods described herein, and some examples include using excess thermal energy for other purposes, scaling the integrated energy storage block, and planning for reactor shutdown while still supplying thermal energy from the integrated energy storage block to the power block, or by enabling the nuclear power block 1102 to charge the integrated energy storage block 1104 during times of reduced power demand. In some cases, the power block 1106 can be operably scaled back to a power output lower than 100% capacity, while the nuclear power block 1102 can operate at 100% operating capacity.

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

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

[0147] In some embodiments, hybrid technology can be used to supplement the thermal energy of the nuclear block 1102. For example, if the power block 1106 requires a higher inlet steam temperature than the nuclear block 1102 can supply, alternative technologies 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 some embodiments, in the integrated energy system 1100, utilizing the isolated power block 1106 assets in conjunction with a nuclear thermal plant provides a number of benefits. For example, the site is already approved and operational, and the placement has already been made, which allows for further utilization in a carbon-free power generation operation rather than having hundreds of millions of dollars of equipment being discarded, and the site is already connected to the transmission infrastructure and the power grid, among other benefits.

[0149] The foregoing description of combining the nuclear power block 1102 and the integrated energy storage block 1104 with the isolated coal power block 1106 assets is equally applicable to isolated natural gas assets. Since gas-fired power plants are decommissioned for any of a number of different reasons, the power blocks from these power plants can be utilized by combining them with the power block 1106 and the integrated energy storage block 1104 that supplies thermal energy, and can drive the turbines of the gas-fired power plants. 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, hydro energy, or any other suitable thermal energy source.

[0150] In some examples where the power block 1106 requires a temperature higher 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 raise the temperature of the heat storage medium or the turbine working fluid to a peak in order to improve the efficiency of the turbine cycle. In addition, although the power block 1106 itself may generate electricity at a lower efficiency because it is below the optimal inlet steam pressure, it can transfer a portion of the generated power to peak the temperature of the inlet steam and gradually increase its efficiency as the inlet steam rises to a more ideal temperature for the power block.

[0151] According to one embodiment, a brownfield site provides an opportunity to utilize isolated equipment by combining the isolated equipment with the integrated energy storage block 1104 and the nuclear power block 1102. By utilizing the existing infrastructure (backbone facilities, social production infrastructure) available at the brownfield site, sites that would otherwise be difficult to use can be rehabilitated and developed into carbon-free energy production facilities at a much lower cost than new construction, and by reducing the licensing and commissioning time and cost, the site can be redeveloped to be actively used.

[0152] The embodiments described herein provide an integrated energy system that decouples a heat energy source from an energy conversion system, which can be used to meet not only industrial process heat but also base electrical load demand and peak electrical load demand, and provides a modular, scalable (expandable and contractible), and efficient system. One or more heat energy sources, for example, among others, one or more nuclear reactors of various types, solar power plants, geothermal energy sources, etc., can be coupled to a shared system of the rest of the plant, such as a thermal energy 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 arrangements of the steps described and / or illustrated herein are given as merely examples and can be changed as desired. For example, the steps illustrated and / or described herein can be shown or described in a particular order, but these steps do not necessarily have to be performed in the order shown or described.

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

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

[0156] As used herein, the term "or" is used inclusively to refer to alternatives as well as combinations of items. As used herein, words such as numbers refer to like elements.

[0157] Embodiments of the invention are shown and described herein as examples only. Those skilled in the art will recognize numerous adaptations, changes, modifications, and substitutions without departing from the scope of this disclosure. Some alternatives and combinations of the embodiments disclosed herein may be utilized without departing from the disclosure of this specification and the scope of the invention disclosed herein. Accordingly, the scope of the invention of this disclosure is to be defined only by the appended claims and their equivalents. This disclosure also includes the following numbered clauses.

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

[0159] 2. The system according to clause 1, further comprising a containment building, wherein the reactor is enclosed within the containment building.

[0160] 3. The system according to clause 1, further comprising a fuel handling area, wherein the fuel handling area is located within the reactor site boundary.

[0161] 4. The system according to clause 1, wherein the thermal energy storage system is in thermal communication with the reactor by means of an energy transfer system.

[0162] 5. The system according to clause 4, wherein the energy transfer system comprises a fluid loop, and the fluid loop forms a closed loop between the reactor and the thermal energy storage system.

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

[0164] 7. The system according to clause 5, wherein the fluid loop comprises a working fluid.

[0165] 8. The system according to clause 7, wherein the working fluid contains a chloride salt.

[0166] 9. The system according to clause 7, wherein the working fluid contains sodium nitrate.

[0167] 10. The system according to clause 7, characterized in that the working fluid contains a eutectic solution.

[0168] 11. The system according to clause 7, characterized in that the working fluid contains a phase change material.

[0169] 12. The system according to clause 7, characterized in that the working fluid contains a miscibility gap alloy.

[0170] 13. The system according to clause 7, characterized in that the working fluid contains molten metal or a metal alloy.

[0171] 14. The system according to clause 6, characterized in that the first heat exchanger or the second heat exchanger is a shell and tube heat exchanger.

[0172] 15. The system according to clause 6, characterized in that the first heat exchanger or the second heat exchanger is a double pipe heat exchanger.

[0173] 16. 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. The system according to clause 1, further comprising a hydrogen generator coupled to the thermal energy storage system.

[0175] 18. The system according to clause 1, characterized in that the reactor site boundary includes a fence.

[0176] 19. The system according to clause 1, characterized in that the reactor is a fast neutron reactor.

[0177] 20. The system according to clause 1, characterized in that the reactor is a fast breeder reactor.

[0178] 21. The system according to clause 1, characterized in that the reactor is a thermal neutron reactor.

[0179] 22. The system according to clause 1, characterized in that the reactor is a heavy water reactor.

[0180] 23. The system according to clause 1, characterized in that the reactor is a light water reactor.

[0181] 24. The system according to clause 1, characterized in that the reactor is a molten salt reactor.

[0182] 25. The system according to clause 1, characterized in that the reactor is a liquid metal cooled reactor.

[0183] 26. The system according to clause 1, characterized in that the reactor is a gas cooled reactor.

[0184] 27. The system according to 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 reactor.

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

[0186] 29. The system according to clause 28, characterized in that the energy transport system is configured to transfer thermal energy from the reactor to the thermal energy storage system.

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

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

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

[0190] 33. The system according to clause 32, characterized in that the closed fluid loop contains molten salt.

[0191] 34. The system according to clause 31, characterized in that the energy supply system includes a working fluid that is in direct contact with the heat storage medium in the thermal energy storage system.

[0192] 35. The system according to clause 1, characterized in that the generator is a steam turbine.

[0193] 36. The system according to clause 35, characterized in that the steam turbine converts steam into mechanical work.

[0194] 37. Furthermore, it includes a generator coupled to the steam turbine by an output shaft of the steam turbine, The system according to clause 36, characterized in that the mechanical work causes the generator to generate electricity.

[0195] 38. The system according to clause 37, characterized in that the generator is configured as a power generation system that follows the load.

[0196] 39. The nuclear reactor is a first nuclear reactor, and the system further includes a second nuclear reactor, characterized in that the system according to claim 1.

[0197] 40. The second nuclear reactor is located on a second nuclear reactor site within the boundary of the second nuclear reactor site. The thermal energy storage system and the generator are located outside the boundary of the second nuclear reactor site, characterized in that the system according to claim 39.

[0198] 41. Furthermore, the system according to claim 1, characterized in that it further includes an auxiliary heat storage system in thermal communication with the nuclear reactor.

[0199] 42. The system according to claim 41, characterized in that the auxiliary heat storage system is configured to adjust the inlet temperature of the core of the nuclear reactor.

[0200] 43. Furthermore, the system according to claim 1, characterized in that it further includes a solar thermal energy system in thermal communication with the thermal energy storage system.

[0201] 44. Furthermore, an emergency planning area is included around the nuclear reactor, and the thermal energy storage system and the generator are located outside the emergency planning area, characterized in that the system according to claim 1.

[0202] 45. 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, characterized in that the system according to any one of the preceding paragraphs.

[0203] 46. The system according to claim 45, characterized in that the primary heat exchanger is a sodium-salt heat exchanger.

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

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

[0206] 49. The system according to clause 48, further comprising a power generation system in thermal communication with the thermal energy storage system, wherein the power generation system is located outside the nuclear power plant boundary.

[0207] 50. The system according to clause 49, wherein the nuclear reactor has a first nameplate capacity, the power generation system has a second nameplate capacity, and the second nameplate capacity is greater than the first nameplate capacity.

[0208] 51. A system comprising: A nuclear reactor having a thermodynamic output; A power generation system having a thermodynamic input in thermal communication with the nuclear reactor; Including the above, The system, characterized in that the thermodynamic input is greater than the thermodynamic output.

[0209] 52. Furthermore, it includes a heat storage system disposed between the nuclear reactor and the power generation system, and the heat storage system receives thermal power from the nuclear reactor and supplies thermal power to the power generation system. The system according to clause 51 is characterized by this.

[0210] 53. The heat storage system is sized to supply thermal power greater than the size that the nuclear reactor can supply. The system according to clause 52 is characterized by this.

[0211] 54. Furthermore, it includes a nuclear reactor site boundary, The nuclear reactor is located within the nuclear reactor site boundary. The system according to clause 51 is characterized by this.

[0212] 55. The power generation system is located outside the nuclear reactor site boundary. The system according to clause 54 is characterized by this.

[0213] 56. It includes a primary heat exchanger, and the primary heat exchanger is a sodium-salt heat exchanger. The system according to any of the preceding clauses is characterized by this.

[0214] 57. The primary heat exchanger is located within the reactor vessel of the nuclear reactor. The system according to clause 56 is characterized by this.

[0215] 58. The first heat exchanger is in thermal communication with the heat storage system. The system according to clause 57 is characterized by this.

[0216] 59. Furthermore, it includes a second nuclear reactor in thermal communication with the heat storage system. The system according to clause 52 is characterized by this.

[0217] 60. The second nuclear reactor is a nuclear reactor with a design different from that of the nuclear reactor. The system according to clause 59 is characterized by this.

[0218] 61. The system according to clause 52, further comprising a solar thermal power plant in thermal communication with the heat storage system.

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

[0220] 63. The system according to any of the preceding clauses, wherein the nuclear reactor is separated from the heat storage system and the power generation system.

[0221] 64. The system according to any of the preceding clauses, further comprising a hydrogen generator that receives thermal energy to generate hydrogen.

[0222] 65. The system according to clause 64, wherein the hydrogen generator includes an electrolysis device.

[0223] 66. The system according to clause 65, wherein the hydrogen generator generates hydrogen through a high-temperature electrolysis process.

[0224] 67. The system according to clause 64, wherein the hydrogen generator generates hydrogen through a steam reforming process with natural gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0225]

Figure 1

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Figure 3

Figure 4

Figure 5

Figure 6

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Figure 8

Figure 9

Figure 10

Figure 11

Claims

1. A system comprising: a nuclear reactor on a nuclear reactor site; a nuclear reactor site boundary surrounding the nuclear reactor, the nuclear reactor site boundary being defined by one or more barriers that suppress access to the nuclear reactor site; a thermal energy storage system located outside the nuclear reactor site boundary, the thermal energy storage system being in thermal communication with the nuclear reactor; a generator in thermal communication with the thermal energy storage system, the generator being located outside the nuclear reactor site boundary; wherein the nuclear reactor is not in direct thermal communication with the generator.

2. The system according to claim 1, wherein the thermal energy storage system is in thermal communication with the nuclear reactor by an energy transfer system.

3. The system according to claim 2, wherein the energy transfer system includes a fluid loop that forms a closed loop between the nuclear reactor and the thermal energy storage system.

4. The system according to claim 3, wherein the fluid loop of the energy transfer system is in thermal communication with the nuclear reactor by a first heat exchanger and in thermal communication with the thermal energy storage system by a second heat exchanger.

5. The system according to claim 4, wherein the fluid loop includes salt as a working fluid.

6. The system according to claim 1, wherein the nuclear reactor site boundary includes a fence.

7. The system according to claim 1, wherein 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.

8. The system according to claim 1, wherein the generator is in thermal contact with the thermal energy storage system by an energy supply system that uses molten salt as a working fluid.

9. The nuclear reactor is a first nuclear reactor, and the system according to claim 1 further includes a second nuclear reactor in thermal communication with the thermal energy storage system.

10. The second nuclear reactor is located on a second nuclear reactor site within a second nuclear reactor site boundary, and the thermal energy storage system and the generator are located outside the second nuclear reactor site boundary.

11. The system according to claim 1, further comprising a solar energy system in thermal communication with the thermal energy storage system. **Claim 12** A system comprising: a nuclear reactor on a nuclear power plant site; a nuclear power plant site boundary surrounding the nuclear reactor, the nuclear power plant site boundary being defined by one or more barriers that suppress access to the nuclear power plant site; a thermal energy storage system located outside the nuclear power plant site boundary, the thermal energy storage system being in thermal communication with the nuclear reactor; a generator in thermal communication with the thermal energy storage system, the generator being located outside the nuclear power plant site boundary; an emergency planning area around the nuclear reactor; and the thermal energy storage system and the generator are located outside the emergency planning area.

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