Cogeneration plant with a nuclear-reactor site, and an industrial site with a chemical production unit, the industrial and nuclear sites being remote from one another and connected by a thermal energy storage closed loop

Abstract

The invention relates to a cogeneration plant (1) with a nuclear-reactor site (2), and an industrial site (3) with a chemical production unit (30), the industrial and nuclear sites being remote from one another and connected by a thermal energy storage closed loop. The invention essentially consists in physically distancing and functionally separating a nuclear site from an industrial site comprising at least one chemical production unit which exploits the heat generated by a reactor block of the nuclear site, this physical distancing being achieved through use of a thermal storage loop with high-temperature reservoirs (42, 44) and low-temperature reservoirs (41, 45) present both on the nuclear site and on the industrial site.

Description

[0001] Description

[0002] Title: Cogeneration installation with a nuclear reactor site, an industrial site with a chemical production unit, the industrial and nuclear sites being distant and connected in a closed loop of thermal energy storage.

[0003] technical field

[0004] The present invention relates to the general field of nuclear reactors, producing heat to generate electricity.

[0005] H can refer to all current and future nuclear reactor types, including light water reactors (LWRs), particularly pressurized water reactors (PWRs), or liquid metal cooled reactors, such as sodium FNRs or SFRs (Sodium Fast Reactor) or lead FFRs (Lead Fast Reactor), or molten salt reactors (MSRs), high-temperature or very high-temperature gas reactors (VHTRs).

[0006] In general, the invention applies to an installation comprising at least one nuclear reactor with an indirect thermodynamic cycle of the family of so-called second, third, fourth generation (GEN IV) reactors.

[0007] More specifically, the invention relates to cogeneration plants comprising such nuclear reactors. "Cogeneration" is used here and within the scope of the invention to mean the simultaneous or non-simultaneous production of electricity and useful heat.

[0008] The main objective of the invention, within the framework of such installations, is to reduce or even eliminate the design constraints of a nuclear reactor and the conditions of its operation and to limit, or even eliminate, any environmental impact of the reactor (withdrawals and discharges of liquid water into the environment).

[0009] Previous technique

[0010] In the context of climate and energy transition, the nuclear industry must meet several challenges for the future. Indeed, to meet the energy and societal challenges of tomorrow, it will be appropriate to design nuclear reactors that make it possible to: - limit the need for so-called "environmental" liquid cooling sources (rivers, streams, sea) and the associated releases into the environment;

[0011] - to be more flexible and therefore more complementary to other so-called renewable energies (RE), to meet the fluctuating demand for electricity and the intermittency of RE;

[0012] - to decarbonize processes by supplying heat to consuming industries (desalination, heat networks, hydrogen...) while increasing energy efficiency;

[0013] - to capture atmospheric CO2 to limit the effects of global warming and contribute to closing the carbon cycle as a source of carbon for industrial processes; and this, without degrading the profitability of the installation, either by economically benefiting from the new services provided, or by significantly increasing the amount of electricity produced during the day.

[0014] Historically, the use of nuclear energy for purely power generation purposes has constrained the design of nuclear facilities. Indeed, because electricity cannot be stored, production had to be closely linked to consumption.

[0015] At the scale of a nuclear power reactor, this translates into a constraint of having to do load tracking and frequency tracking and therefore, to vary the power of the reactor.

[0016] In terms of design, this constraint led to the need to group the functions of nuclear heat production and electricity conversion as close as possible to each other on a single site, operated by the same operator. This functional coupling between the nuclear reactor and its thermal energy conversion system (TEC) on the same site implies the need to produce steam near the reactor to power the TEC's turbine and to position the nuclear site near a cold source (river or sea) to dissipate the thermal power not converted into electricity by the TEC.

[0017] Furthermore, in terms of operation, the aforementioned constraint necessitates responding to variations in electricity demand by directly adjusting the reactor core power output. Load following, directly linked to the control of nuclear power production, leads to design and safety management constraints for the nuclear site and can reduce its operating life before decommissioning.

[0018] Therefore, to date, a nuclear facility must include, within the same site, a reactor that produces heat and is controllable to meet load and frequency monitoring requirements, and a suitable energy management system (EMS) to optimally convert the core's thermal power into electricity. Specifically, this EMS must be sized for a power output at least equal to that of the nuclear reactor.

[0019] New approaches to using nuclear energy to meet new markets are leading to its valorization in the cogeneration of electricity and heat.

[0020] Thus, some reactors are called cogeneration reactors, because they are dedicated to both the production of electricity and heat, simultaneously or not.

[0021] As detailed in [1], the principle of cogeneration from a nuclear reactor involves modifying the design of the energy conversion cycle so that the heat is released at the cold source at a temperature that allows for its use. Indeed, limiting global warming requires minimizing heat losses at all levels and, in particular, at the cold source of a thermodynamic installation. This cogeneration objective becomes all the more relevant for a nuclear reactor since industrial or domestic heat is often traditionally obtained by burning fossil fuels, which are responsible for greenhouse gas emissions.

[0022] Furthermore, the prospects for deploying smaller power reactors (SMRs) make it easier to consider storing the thermal energy produced.

[0023] Work carried out by the Applicant has highlighted that the functionalities usually entrusted to the heat-to-electricity conversion system of a nuclear reactor and, consequently, to the reactor itself, are evolving with an approach of combined heat and power generation and the supply of new markets, such as the production of hydrogen, molecules of interest, and industrial heat.

[0024] Patent application WO2024 / 133496 proposes an indirect optimal thermal coupling between an SMR-type nuclear reactor and a high-temperature electrolytic hydrogen production unit. Patent application FR2406736, filed on June 21, 2024, discloses a production unit for at least one synthetic kerosene fuel, the necessary hydrogen for which is supplied by an electrolytic hydrogen production unit itself thermally coupled to a thermal power plant, which may be an SMR-type nuclear reactor.

[0025] The cogeneration operation of the SCE conversion system is achieved in these patents by the addition of thermohydraulic loops.

[0026] Thus, this integrated approach and the pursuit of energy efficiency have led to the development of a previously unused feature of the SCE conversion system in a purely generator-based system. This feature involves considering the SCE conversion system's ability to reintegrate heat flows of varying power and temperature to maximize the system's energy efficiency.

[0027] Furthermore, the production units coupled to the SCE system are not subject to load following variations: the production of hydrogen or kerosene is constant and there is no attempt to vary it over short time steps.

[0028] The functions performed by a nuclear reactor are therefore evolving towards greater simplification.

[0029] That being said, there is a need to further improve nuclear reactors, particularly when implemented in cogeneration plants, by simplifying:

[0030] - their design constraints, including simplification of safety, power ramps, elimination of the presence of steam in the reactor building, reduction of power variations which cause damage / aging of structures;

[0031] - territorial location constraints to potentially no longer have the reactor positioned on the edge of natural water (sea or river);

[0032] - the conditions for controlling a nuclear reactor to avoid load and frequency following.

[0033] The aim of the invention is to at least partially meet this need.

[0034] Description of the invention

[0035] To this end, the invention relates, in one of its aspects, to a nuclear power cogeneration plant comprising: - a nuclear site comprising:

[0036] • at least one reactor block, delimited by a reactor vessel, the reactor block comprising all the components and part of the fluidic circuit, including the reactor core which generates heat through nuclear fission reactions, and which is housed inside the reactor vessel,

[0037] • at least one first fluidic circuit, called the primary circuit, comprising at least one first intermediate heat exchanger, connected in a closed hydraulic loop with the reactor block,

[0038] • part of a closed loop thermal energy storage comprising, at least a first tank called a cold tank and at least a second tank called a hot tank, connected respectively to an inlet and an outlet of the first intermediate heat exchanger;

[0039] - an industrial site, located away from the nuclear site, comprising:

[0040] • another part of the closed-loop thermal energy storage system comprising at least one third tank, referred to as the hot tank, and at least one fourth tank, referred to as the cold tank,

[0041] • at least one chemical production unit, integrated into the other part of the closed-loop thermal energy storage system, between the hot and cold tanks, so as to utilize the heat produced by the reactor block of the nuclear site,

[0042] - a second fluid circuit closing the closed loop of thermal energy storage, comprising:

[0043] • at least one initial fluid line, running from the nuclear site to the industrial site and connecting the hot tanks,

[0044] • at least one second fluidic line, arranged from the nuclear site to the industrial site and connecting the cold tanks together;

[0045] - at least one hydraulic pump to circulate a heat transfer fluid in the closed thermal storage loop.

[0046] For the purposes of this invention, "nuclear site" means a site generating heat for the production of electricity and / or heat and which operates from at least one nuclear reactor as a heat source, but which, unlike nuclear sites according to the state of the art, does not include a system for converting the thermal energy from the nuclear reactor(s) (SCE) into electricity.

[0047] A suitable nuclear site within the scope of the invention is therefore devoid of a thermal energy-to-electricity conversion system and may include one or more light water reactors (LWRs), particularly pressurized water reactors (PWRs) with conversion cycle inlet temperatures of nearly 300 °C, or one or more Generation IV reactors (GEN IV), particularly small modular reactors (SMRs), or advanced nuclear reactors (AMRs). For example, it may be liquid metal-cooled fast neutron reactors, particularly liquid sodium-cooled reactors known as SFRs (Sodium Fast Reactors), which belong to the Generation IV reactor family.

[0048] For the purposes of this invention, "SMR reactor" means the usual technological meaning, namely a nuclear fission reactor, smaller in size and power than conventional SLR reactors, some of whose blocks are manufactured in a factory and transported to a nuclear site for installation.

[0049] For the purposes of this invention, "reactor block" means the reactor vessel, as well as all the components and parts of the fluidic circuit, including the reactor core which generates heat through nuclear fission reactions, and which is housed inside the reactor vessel.

[0050] A nuclear site as defined by French regulations includes the nuclear pilot, i.e. the reactor building, the fuel building plus the safety auxiliaries, and the so-called conventional pilot which is beyond the third containment barrier.

[0051] According to an advantageous embodiment, the installation comprises:

[0052] - at least one first hydraulic pump, arranged at the outlet of the cold tank of the part of the closed thermal storage loop on the nuclear site;

[0053] - at least one second hydraulic pump to circulate a heat transfer fluid, located at the outlet of the hot tank of the closed thermal storage loop at the industrial site. This mode corresponds to a reference configuration of the installation. Thus, in this reference configuration, the installation is operated using two hydraulic pumps, one of which is located at the nuclear site at the outlet of the cold tank on the pipe supplying the reactor's intermediate heat exchanger, and the other is located at the industrial site.

[0054] In general, to manage the levels of heat transfer fluid in the tanks and maintain the required levels corresponding to the reserves inside these tanks which must be left free or available, different embodiments are possible.

[0055] Thus, in another reference configuration, two additional pumps can be added to the fluidic branches between the sites, one being on the branch connecting the two hot tanks and the other connecting the two cold tanks.

[0056] In certain specific configurations, and taking into account the topography between sites, the operation of the installation could be simplified by removing one or two pumps and installing connections at different elevations on the tanks equipped with isolation valves. Thus, the installation could be designed with a single hydraulic pump to circulate the heat transfer fluid in the thermal storage loop.

[0057] Advantageously, the industrial site is located at a distance of up to several tens of kilometers from the nuclear site.

[0058] According to an advantageous embodiment, the industrial site includes at least one thermal energy-to-electrical energy conversion (TEE) system, capable of being connected to a local or national electrical network, an input and an output of the TEE system being connected respectively to the hot and cold tank of the industrial site, the chemical production unit being thermally coupled and electrically connected to the TEE system, and / or thermally coupled to the hot tank via a heat exchanger, so as to be supplied respectively by the heat and electricity required for chemical production.

[0059] For the purposes of this invention, "chemical production unit" means any unit capable of producing or transforming molecules of interest or chemical compositions (glass, paper, cardboard, etc.).

[0060] The invention essentially consists of physically relocating and functionally separating a nuclear site from an industrial site comprising at least one chemical production unit which uses the heat produced by a reactor block of the nuclear site, this physical relocation being achieved by a thermal storage loop with hot and cold tanks present both on the nuclear site and on the industrial site.

[0061] The physical separation between a nuclear site and an industrial site, potentially classified as Seveso in France, allows for the separation of the risks specific to these sites. More generally, with this new installation configuration, the operator of a nuclear site has prerogatives limited to heat production, while the operator of an industrial site where there is at least one chemical production unit, particularly for synthetic molecules, is responsible for operating the dedicated energy conversion system (ECS).

[0062] Beyond simply distancing the industrial site from the nuclear site, the judicious presence of hot and cold tanks both on the nuclear site and on the industrial site makes it possible to overcome the transients of start-up, shutdown, and load variation.

[0063] Thus, the hot and cold tanks on the nuclear site make it possible to manage all incidental and accidental situations that would occur beyond the tanks located on the nuclear installation, without there being a need for an emergency shutdown of the reactor block.

[0064] Furthermore, the ducts (outlets) for its heat production are easier to expand than in the case of a state-of-the-art, locally integrated heat recovery system (HRS) at the nuclear site. An additional benefit is that incidental and accidental events occurring at a remote industrial site, isolated from the nuclear site, will have a less severe impact than in the case of a traditional coupling with a state-of-the-art HRS.

[0065] The hot and cold tanks on the industrial site make it possible to decouple its own operating perimeter, and to manage production transients.

[0066] The invention could put an end to the paradigm whereby a nuclear reactor of significant power is always positioned on the edge of the sea or a river.

[0067] In the end, a nuclear cogeneration plant according to the invention has many major advantages, including: a potential simplification of safety and operability constraints for the operator, - freedom of geographical location in countries with a dry climate, not benefiting from a river, stream or sea in their geography;

[0068] - a simplification of the perimeter of a nuclear site since potentially the invention makes it possible to no longer have to produce steam on the nuclear site itself;

[0069] - a significant reduction in the cost of constructing the nuclear site, because it can do without part of the buildings and utilities dedicated to the SCE, as in the state of the art;

[0070] - total flexibility / adaptability of the configuration of the industrial site and, in particular, of the SCE conversion system installed there (nominal power, location of withdrawals...), without any impact on the nuclear reactor and this throughout the life of the installation;

[0071] - the possibility of supplying an industrial site directly with the highest level of heat, unlike heat extraction in a state-of-the-art SCE which is carried out at a minimum in the high-pressure turbine, therefore at a lower temperature;

[0072] - a contractual simplification: the operator of the nuclear site sells heat to an industrial company that manages a site remotely;

[0073] - a possible simplification of the design / safety of the nuclear reactor which no longer has to do load / frequency tracking, nor potentially produce steam;

[0074] - increased competitiveness due to the ability to operate the nuclear reactor at 100% throughout its availability, thanks to thermal storage tanks;

[0075] - the greatly simplified possibility of serving several industrial sites with their specific requirements for combined heat and power (CHP) generation. This is all the more advantageous as it seems difficult to standardize a configuration that would only power a single industrial chemical production unit, due to differences in lifespan and power output.

[0076] Other advantages and features of the invention will become clearer upon reading the detailed description of examples of implementation of the invention given by way of illustration and not limitation with reference to the following figures.

[0077] Brief description of the drawings

[0078] [Fig. 1] Figure 1 schematically illustrates a configuration of an installation with a nuclear reactor site and a remote industrial site according to the invention. [Fig. 2] Figure 2 is a schematic view of a cogeneration installation configuration with a nuclear reactor site and a remote industrial site according to an embodiment of the invention, where the industrial site includes a thermal energy conversion system (TEC).

[0079] [Fig 3] Figure 3 is a schematic view of a cogeneration plant configuration with a nuclear reactor site and a remote industrial site according to an embodiment of the invention, where the industrial site comprises several chemical production units each with its own thermal energy conversion system (TEC).

[0080] [Fig 4] Figure 4 reproduces a configuration according to Figure 2, showing a P control of the reactor block achieved with the flow rate of the heat transfer fluid.

[0081] [Fig 5] Figure 5 shows a configuration according to Figure 3 with two production units, each with its SCE system, and shows a P control of the reactor block carried out with the flow of heat transfer fluid.

[0082] [Fig 6] Figure 6 is a schematic longitudinal cross-sectional view of a single stratified thermal storage tank acting as both hot and cold reservoir of the second thermal storage loop according to the mode of Figure 12.

[0083] Detailed description

[0084] Throughout this application, the terms "upstream" and "downstream" are to be understood by reference to the direction of flow of a heat transfer fluid within one of the fluid circuits of a nuclear cogeneration plant according to the invention.

[0085] The dotted lines on all the figures represent the respective physical boundaries of the nuclear and industrial sites in a nuclear cogeneration plant according to the invention.

[0086] Figure 1 shows an installation 1 according to the invention comprising a nuclear site 2 physically and functionally separated from an industrial site 3 supplied by the heat delivered by the nuclear site 2.

[0087] Each of these two sites, 2 and 3, must meet its own constraints and comply with standards independently of the other. The distance D separating the two sites, 2 and 3, is preferably between a few hundred meters and several tens of kilometers.

[0088] Nuclear site 2 includes, firstly, at least one reactor block 20, delimited by a reactor vessel. The reactor block comprises all the components and part of the fluid circuit, including the reactor core, which generates heat through nuclear fission reactions and is housed inside the reactor vessel. Reactor block 20 may be an SMR reactor, typically of the PWR type.

[0089] A first fluidic circuit, called the primary circuit 21, includes at least one first intermediate heat exchanger 22, connected in a closed hydraulic loop with the reactor block 20 and often a hydraulic pump 23 to circulate the fluid from the primary circuit in the closed hydraulic loop.

[0090] The reactor block 20, the primary circuit with the intermediate exchanger 22 and the pump 23 are housed as usual in a reactor building 24.

[0091] Part 40 of a closed loop thermal energy storage 4 is also arranged on the nuclear site 2. This part 40 of the closed loop 4 includes, at least a first tank called the cold tank 41 and at least a second tank called the hot tank 42, connected respectively to an inlet and an outlet of the first intermediate heat exchanger 22.

[0092] Industrial site 3, located away from the nuclear site, includes another part 43 of the closed thermal energy storage loop 4. This other part 43 includes at least a third tank called the hot tank 44 and at least a fourth tank called the cold tank 45.

[0093] At least one chemical production unit 30 is arranged on the industrial site 3 and is integrated into part 43 of the closed loop, between the hot tanks 44 and cold tanks 45, so as to be supplied with the heat required for chemical production.

[0094] A second fluidic circuit 5 closes the closed thermal energy storage loop 4, with at least a first fluidic line 50, arranged from the nuclear site 2 to the industrial site 3 and connecting the hot tanks 42, 44 and at least a second fluidic line 51, arranged from the nuclear site 2 to the industrial site 3 and connecting the cold tanks 43, 45. The length of these fluidic lines 50, 51 corresponds to the desired distance D to separate the two sites 2, 3 which is preferably between 500 and 1000 m.

[0095] At least one hydraulic pump allows a heat transfer fluid to circulate in the closed thermal storage loop 4.

[0096] In the illustrated embodiment, at least one first hydraulic pump 46 is arranged at the outlet of the cold storage tank 41 of the closed thermal storage loop at the nuclear site. The hydraulic pump 46 is preferably located downstream of the cold storage tank.

[0097] 41 and arranged in reactor building 24.

[0098] At least one second hydraulic pump 47 is arranged at the outlet of the hot tank 44 of the closed thermal storage loop at the industrial site. The hydraulic pump is preferably upstream of the heat exchanger of the chemical production unit 30, which exchanges heat with the thermal storage loop.

[0099] The fluid branches of loop 4 consist of cylindrical pipes with metal walls, resistant to the chemical attack of the heat transfer fluid at high temperatures, typically above 150°C, and insulated externally with high-temperature insulation. The diameter of each pipe is calculated to allow the dissipation of all the thermal power with a maximum permissible flow velocity of the heat transfer fluid, typically on the order of 5 to 10 m / s.

[0100] The hot tanks 42 and 44 contain the heat transfer fluid, store all the heat recovered from the intermediate heat exchanger 22, and supply heat to the chemical production unit 30. Each hot tank 42 and 44 can be cylindrical in shape, with walls made of metal resistant to the chemical attack of the heat transfer fluid at high temperatures, typically above 150°C, and is lined with an external high-temperature insulating layer to limit heat loss. The dimensions (usable storage volume) of the hot tanks 42 and 44 depend on the characteristics of the heat transfer fluid used. For safety reasons, the hot tank

[0101] Tank 42 is located at a distance, typically at a preliminaryly estimated distance of 60 m from the containment of reactor 24 with an intermediate embankment, on nuclear site 2. Tank 42 can be equipped with a heat transfer fluid preheating system to ensure that the fluid is maintained in a liquid state and / or a level measurement system with alarm reporting and / or a safety overflow connected directly to the cold tank 4L. For safety reasons, the hot tank 44 can also be arranged at a distance from the chemical production unit 30, on industrial site 3.

[0102] Each of the hydraulic pumps 23, 46, and 47 is designed to operate at least at the nuclear reactor's Kd availability coefficient. Typically, Kd is around 90%. Each of the pumps 23, 46, and 47 has metal walls resistant to the chemical attack of the heat transfer fluid at high temperatures, typically above 150°C. Several pumps 23 or 46 can be positioned in parallel to distribute the pumping flow rate, and a redundant pump can be provided for safety reasons.

[0103] Each of the cold tanks 41 and 45 has approximately the same heat transfer fluid storage volume as the hot tanks 42 and 44 located on the same site. Each of the cold tanks 41 and 45 can be cylindrical in shape, with walls made of metal resistant to the chemical attack of the heat transfer fluid at high temperatures, typically above 150°C, and is lined with an external high-temperature insulating layer to limit heat loss. The sizing (usable storage volume) of the cold tanks 41 and 45 depends in particular on the characteristics of the heat transfer fluid used. For safety reasons, the cold tank 41 is located at a distance, typically at a preliminary estimate of 60 m from the containment of reactor 24 with an intermediate embankment, on nuclear site 2.Tank 41 can be equipped with a heat transfer fluid preheating system to ensure the fluid remains in a liquid state and / or a level measurement system with alarm reporting and / or a safety overflow connected directly to the hot tank 42. For safety reasons, the cold tank 45 can also be located away from the chemical production unit 30, on the industrial site 3.

[0104] The heat transfer fluid is a molten salt type, remaining in a liquid phase over a temperature range of 100°C to 700°C, with a 40°C margin above the maximum operating temperature. Preferably, for a pressurized water reactor (PWR), the salt will have the following chemical composition: 53% KNO3, 40% NaNO2, 7% NaNO3 (HITEC® salt). Advantageously, the choice of the salt's chemical composition and associated physicochemical characteristics will be adapted to the temperature levels of the heat produced by the nuclear reactor. Figure 2 shows an embodiment of the invention in which installation 1 is a cogeneration plant with industrial site 3, which includes at least one heat-to-electrical energy conversion (HTE) system 6, located outside nuclear site 2. This HTE system is capable of being connected to an electrical grid.An inlet and an outlet of the SCE system are connected respectively to the hot tank 44 and the cold tank 45 of the industrial site.

[0105] As illustrated, the chemical production unit 30 is thermally coupled and electrically connected to the SCE 6 system, so that it is supplied with the heat and electricity required for production on the industrial site, respectively. The SCE 6 system is preferably a Rankine cycle. The heat draw-off and return points are advantageously chosen to meet the needs and characteristics of the unit 30, i.e., supply at intermediate temperature levels. It is also possible to connect the hot tank 44 to the industrial process 30, without drawing heat from the SCE 6, via a heat exchanger. This variant allows for the use of heat at the highest available temperature.

[0106] More specifically in this figure 2, the industrial site configuration 3 is carried out with a chemical production unit 6 dedicated to the production of synthetic molecules.

[0107] In this configuration, production unit 6 comprises several units that operate and interact to produce synthetic molecules.

[0108] In this configuration, as symbolized, the production unit 30 releases waste heat which is returned to the Rankine cycle 6 and then to the cold reservoir 45.

[0109] The Rankine cycle 6 can be coupled to a water reservoir 31 which can supply the EHT electrolysis unit of the production unit 30 and, by return, reinject water into the Rankine cycle 6.

[0110] Figure 3 illustrates a configuration where the industrial site 3 comprises several production units 30.1, 30.2, 30.3 and several thermal energy-to-electrical energy (TEE) systems 6.1, 6.2, 6.3. Each production unit 30.1, 30.2, 30.3 is thermally coupled and electrically connected to an TEE system 6.1, 6.2, 6.3, independent of the other TEE systems, so as to be supplied with the heat and electricity required for chemical production, respectively. An inlet and an outlet of each SCE system are connected respectively to a hot tank 44 and a cold tank 45 of the industrial site 3. As illustrated in figures 4 and 5, the control P of the reactor block 20 is preferably carried out with the flow of heat transfer fluid, preferably a salt, entering the intermediate exchanger 22. Similarly, the control P of the heat supply of the SCE(s) of the industrial site 3 is done by regulating the flow of the corresponding branch(es) 43, 43.1, 43.2.This regulation can be achieved through conventional technological means, for example parallel pumps and / or variable speed pumps and / or adjustable valves.

[0111] The inventors made an assessment of the sizing of the vacuum and heat transfer fluid reserves which were to be provided in the cold tanks 41, 45 and hot tanks 42, 44, as well as the power variation of the chemical production unit 30, based on pilot assumptions P and considering the maximum permissible power variation ramps.

[0112] Indeed, in terms of kinetics and operating power, the operating rules for a nuclear reactor such as a reactor block 20 allow a maximum power output variation of 5% / min. In other words, the power ramps, which are set as steeply as possible, are 5% of the reactor 20's nominal power per minute.

[0113] An example of dimensioning all the components of the cycle is established from an internal software, used under the name CYCLOP, qualified by the applicant for dimensioning in steady state of thermodynamic conversion cycle.

[0114] The use of this software is described, for example, in [2] or [3]. Sizing can also be performed using other commercial software, notably that under the name THERMOELEX®.

[0115] Table 1 below details the sizing calculations performed.

[0116] [Table 1]

[0117] With these considerations of maximum power variation ramps of 5% / min between 100 and 0% of the available power of reactor block 20 (here on the order of 540 MWth) and, as illustrated in Figure 4, for a single chemical production unit 30 (of the same nominal power as reactor block 2) with its SCE system which undergoes a ramp of X% / min between 100 and 0% of its nominal power, and with a heat transfer fluid consisting of a HITEC® type salt:

[0118] - The cold storage tank 41 must always have a reserve of salt available with a volume equal to 1723 m³ 3 - the hot tank 42 must always have an available vacuum reserve with a volume equal to 1723 m 3 ,

[0119] - the hot tank 44 must always have a reserve of salt available whose volume is equal to that of the cold tank 41, multiplied by 5 and divided by X, - the cold tank 45 must always have a reserve of vacuum available whose volume is equal to that of the hot tank 41, multiplied by 5 and divided by X.

[0120] When the industrial site 2 comprises several production units 30.1, 30.2 in parallel, each thermally coupled to cold tanks 45.1, 45.2 and hot tanks 44.1, 44.2 and capable of being electrically connected to its own SCE system 6.1, 6.2, the evaluations with the same assumptions can be made in a similar way.

[0121] Thus, with the same considerations, as illustrated in Figure 5, for two chemical production units 30.1, 30.2 each with its SCE system 6.1, 6.2 and a hydraulic pump 47.1, 47.2 dedicated to the circulation of the heat transfer fluid, which vary respectively at X% / min and Y% / min of their nominal power (respectively a% and (1- a)% of that of reactor block 20, i.e. here on the order of 540 MWth), and with a heat transfer fluid consisting of a HITEC® type salt:

[0122] - the cold storage tank 41 must always have a reserve of salt available with a volume equal to 1723 m3,

[0123] - the hot tank 42 must always have an available vacuum reserve with a volume equal to 1723 m3,

[0124] - the hot tank 44.1 must always have a reserve of salt available whose volume is equal to that of the cold tank 41, multiplied by 5 and divided by X and multiplied by a,

[0125] - the cold tank 45.1 must always have an available vacuum reserve whose volume is equal to that of the hot tank 42, multiplied by 5 and divided by X, and multiplied by a,

[0126] - the hot tank 44.2 must always have a reserve of salt available whose volume is equal to that of the cold tank 41, multiplied by 5 and divided by Y and multiplied by (1- a),

[0127] - the cold tank 45.2 must always have an available vacuum reserve whose volume is equal to that of the hot tank 42, multiplied by 5 and divided by Y, and multiplied by (1 -a).

[0128] Figure 6 shows an advantageous variant where the hot 44 and cold 45 tanks of the industrial site are constituted by a single stratified thermal storage tank. This single tank can also be used at the nuclear site. The invention is not limited to the examples just described; in particular, features of the illustrated examples can be combined in variants not shown.

[0129] Specifically, power variations are not necessarily linear ramps and / or are not necessarily simultaneous, for example in the case of multiple industrial sites, and / or may involve partial changes in power levels from or to intermediate power levels. Similarly, the flow control mode accommodates a steady-state operating regime during which no site experiences load variation.

[0130] Other variants and embodiments may be considered without departing from the scope of the invention.

[0131] The nuclear cogeneration plant just described in relation to a pressurized water nuclear reactor can be implemented with all indirect thermodynamic cycle nuclear reactors, for which the heat production cycle is physically separated from the energy conversion cycle, such as a heavy water reactor or a 4-ton nuclear reactor. eme Generation involving different temperature levels in the conversion cycle.

[0132] Thus, while the detailed example concerns a small pressurized water reactor (SMR), a cogeneration plant can be considered with a large or conventional reactor. The thermodynamic cycle can be of the Rankine, Brayton, or even another technology.

[0133] If in the illustrated example, the primary circuit of the nuclear site includes a hydraulic pump 23 to circulate the fluid from the primary circuit in the closed hydraulic loop, the invention can entirely be implemented without a hydraulic pump in the primary circuit.

[0134] The invention can be implemented with any unit for the production of synthetic molecules or for chemical production or transformation involving an exothermic reaction, such as the production of methanol, ammonia, or methane. The more exothermic and high-temperature the reaction, the greater the amount of waste heat reinjected back into the thermodynamic cycle at the industrial site, and the improved the energy efficiency. For hydrogen production, the industrial site may include a high-temperature electrolysis (HTE) unit, or one implementing alkaline electrolysis, or PEM or AEM.

[0135] The possibility of electrically connecting the industrial site to the grid can be envisaged, in particular to guarantee a fuel production base in the event of a reactor shutdown / maintenance at the nuclear site or a transient operation, and / or in the case where the reactor is not solely dedicated to fuel production while maintaining a thermal connection with the process.

[0136] List of references cited [1]: "Improving energy efficiency by using cogeneration in electricity production" Jean-Marie Loiseaux, Henri Safa, Bernard Tamain, Save the Climate Network.

[0137] [2]: D. Haubensack et al., “The COPERNIC / CYCLOP computer tool: pre-conceptual design of generation 4 nuclear systems, HTR-2004”, 2nd International Topic Conference for the HTGR, September 22-24, 2004, Beijing, China, 2004. [3]: H.D. Nguyen, N. Alpy, D. Haubensack. “Insight on electrical and thermal powers mix with a Gen2 PWR: Rankine cycle performances under low to high temperature grade cogeneration.” Energy, Elsevier, 2020, 202, pp.117518. ffl0.1016 / j. energy.2020.117518ff. ffcea-02569231f.

Claims

Demands 1. Installation (1) comprising: - a nuclear site (2) comprising: at least one reactor block (20), delimited by a reactor vessel, the reactor block comprising all the components and part of the fluidic circuit, including the reactor core which creates heat by nuclear fission reactions, which is housed inside the reactor vessel, at least one first fluidic circuit, called the primary circuit (21), comprising at least one first intermediate heat exchanger (22), connected in a closed hydraulic loop with the reactor block, a part (40) of a closed thermal energy storage loop (4) comprising, at least one first tank called the cold tank (41) and at least one second tank called the hot tank (42), connected respectively to an inlet and an outlet of the first intermediate heat exchanger; - an industrial site (3), at a distance from the nuclear site, comprising: another part (43) of the closed loop thermal energy storage comprising at least a third tank called a hot tank (44) and at least a fourth tank called a cold tank (45), at least one chemical production unit (30), integrated into the other part of the closed loop thermal energy storage, between the hot and cold tanks, so as to exploit the heat produced by the reactor block of the nuclear site; - a second fluidic circuit (5) closing the closed thermal energy storage loop (4), comprising: at least one first fluidic line (50), arranged from the nuclear site to the industrial site and connecting the hot tanks together, at least one second fluidic line (51), arranged from the nuclear site to the industrial site and connecting the cold tanks together, at least one hydraulic pump (46) to circulate a heat transfer fluid in the closed thermal storage loop.

2. Installation (1) according to claim 1, comprising: - at least one first hydraulic pump (46), arranged at the outlet of the cold tank of the part of the closed thermal storage loop on the nuclear site; - at least one second hydraulic pump (47) to circulate a heat transfer fluid, arranged at the outlet of the hot tank of the part of the closed thermal storage loop on the industrial site.

3. Installation according to claim 1 or 2, the industrial site being distant from the nuclear site by a distance (D) which can be up to several tens of kilometers.

4. Installation according to any one of the preceding claims, the industrial site comprising at least one thermal energy to electrical energy conversion (TEE) system (6), capable of being connected to a local or national electrical network, an input and an output of the TEE system being connected respectively to the hot and cold tank of the industrial site, the chemical production unit being thermally coupled and electrically connected to the TEE system, and / or thermally coupled to the hot tank via a heat exchanger, so as to be supplied respectively by the heat and electricity required for chemical production.

5. Cogeneration plant according to claim 4, the chemical production unit implementing an exothermic reaction of which at least part of the high temperature and / or low temperature waste heat is reinjected into the SCE system of the industrial site.

6. Installation according to claim 5, the chemical production unit being a production unit for at least one synthetic fuel or an organic chemical compound, adapted to carry out an exothermic synthesis reaction; the production unit being connected to an electrolysis unit, preferably a high-temperature electrolysis unit, by a fluidic circuit so as to be supplied with hydrogen.

7. Installation according to claim 6, further comprising at least one direct carbon dioxide capture (DAC) unit, connected to the production unit of at least one synthetic fuel by a fluidic circuit and thermally coupled to the thermal power plant by a fluidic circuit so as to respectively supply the CO2 necessary for the reaction exothermic synthesis of the production unit and to be supplied with heat necessary for the direct capture of CO2.

8. Installation according to any one of the preceding claims, the SCE system implementing a Rankine cycle comprising an alternator adapted to supply at least part of its electricity to the electrolysis unit and where appropriate to the direct carbon dioxide capture (DAC) unit.

9. Installation according to any one of claims 6 to 8, the synthetic fuel production unit being adapted to implement a reverse water gas shift (RWGS) process and / or a Fischer-Tropsch (FT) process and where appropriate a reforming process.

10. Installation according to any one of claims 4 to 9, the industrial site(s) comprising several production units (30.1, 30.2, 30.3) and several thermal energy to electrical energy conversion (TEE) systems, each production unit being thermally coupled and electrically connected and / or thermally coupled to the hot tank via a heat exchanger, to an TEE system independent of the other TEE systems, so as to be supplied respectively by the heat and electricity required for chemical production, an inlet and an outlet of each TEE system being connected respectively to a hot tank and a cold tank of the industrial site.

11. Installation according to claim 10, each industrial site comprising an SCE system and a hot tank (44) and a cold tank (45).

12. Installation according to any one of the preceding claims, the hot and cold tanks of the industrial site and / or nuclear site being constituted by a single stratified thermal storage tank.

13. Installation according to any one of the preceding claims, each of the hot and cold tanks at both the nuclear site and the industrial site having a volume of at least 5000 m³ 3 .

14. Installation according to one of the preceding claims, the industrial site comprising at least one SMR nuclear reactor block, in particular a pressurized water reactor (PWR) or a fast neutron reactor in particular cooled with sodium (NaNFR).

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