Liquid metal nuclear reactor with heat transferred through fins

Abstract

The present invention relates to a liquid metal or alloy or molten salt nuclear reactor whose heat produced is transferred by heat transfer fins to be used to produce electricity and / or heat. This nuclear reactor is designed to meet the safety criteria defined for a fourth generation nuclear reactor, capable of consuming nuclear fuel stored in the form of waste.

Description

[0001] The present invention relates to a liquid metal or alloy or molten salt nuclear reactor whose heat produced is transferred by heat-transfer fins to be used to produce electricity and / or heat. This nuclear reactor is designed to meet the safety criteria defined for a fourth generation nuclear reactor, capable of consuming nuclear fuel stored in the form of waste, and to ensure the energy sovereignty of a country. State of the art:

[0002] The growth of the world's population over the past two centuries is largely due to advances in modern medicine and improved living standards. This has significantly reduced infant, child, and maternal mortality, contributing to increased life expectancy. The current world population is 7.6 billion. It continues to increase, but at a slower rate than in the past. It is expected to grow by 1 billion within 15 years and by another 1 billion within 25 years, reaching 10 billion people in 2050. These projections are based on average variations, which assume a decline in the fertility rate and an increase in life expectancy. This population increase goes hand in hand with a growing need for energy.

[0003] Furthermore, around 90% of its global production comes from fossil fuels such as coal, gas and oil. Finding energy sources compatible with high and sustainable development is therefore one of the major challenges of the 21st century.

[0004] The development of clean energy technologies that can reduce dependence on fossil fuels is therefore of great interest, particularly as a generator of electricity and / or heat.

[0005] The concept of a liquid metal or molten salt reactor was first proposed in 1946 by the United States to create a nuclear-powered supersonic jet. Corrosion caused by pipes cracked by hot salt and the low radioactivity of thorium made it very difficult to develop fission reactions at sustainable levels without the addition of uranium.

[0006] It is customary in reactor engineering (see US, JP, RU, FR, CN docs) to propose the use of liquid metals because they are alloys with low melting points. This allows an operating temperature range generally higher than ambient temperature even at ambient pressure. Liquid metals or alloys can be used as coolants because they have excellent heat transfer properties and are used in low pressure systems. This is the case in a sodium-cooled reactor (Phénix, Astrid). In addition, liquid metals or alloys absorb very little neutrons, which allows the reactor to operate with a fast neutron spectrum. Therefore, a liquid metal or alloy fast reactor is a high power density reactor that does not necessarily require a neutron moderator.The main differences between thermal reactors and fast reactors are in fact the neutron cross sections, which have a significant energy dependence. However, it should be noted that the disadvantage of many alloys lies in their high chemical activity, particularly their interaction with oxygen and water or other materials.

[0007] In most known reactors, the core is enclosed in a reflective enclosure capable of reflecting the neutrons generated by nuclear fission; the liquid metal or molten salts / fuel is pumped from the core to the exchanger by a pump arranged outside the core enclosure. Furthermore, the use of control rods remains necessary to avoid any risk of heating the core. These control rods are generally mounted sliding in the longitudinal direction of the reactor so that they can be more or less immersed in the reactor core. They allow, in combination with a moderator structure and depending on the length of the immersed control rod, to control the fuel temperature and the speed of the neutrons generated by fission. Controlling the reactor with such control rods is particularly delicate.In addition, the presence of such control rods significantly increases the height and size of known reactors. Finally, an emergency cooling circuit is generally provided in older reactors. This increases the manufacturing and maintenance costs of the reactors.

[0008] For example, US0027536 describes a portable heat pipe reactor concept that has a solid stainless steel monolithic core. A heat pipe reactor has the advantage of not requiring an active pump. However, the fuel and heat pipe configuration of the solid monolith can cause neutron leakage and absorption by the monolith.

[0009] For example, patent JP2014 / 119429 describes in one of its configurations a molten salt reactor whose cooling circuit does not pass through the reactor core but uses fins integral with the vessel and a thermo-syphon which are enclosed in a common enclosure. This configuration presents a common mode, a risk of disabling the thermo-syphon, and it does not appear to include a corium receptacle to ensure a high level of safety.

[0010] For example, patent WO2016 / 197807 describes a molten salt reactor whose cooling circuit passes through the reactor core. This configuration presents a safety risk, particularly in the event of a cooling circuit failure.

[0011] For example, patent GB2543461 describes a recommendation for a reactor building, including the future AP1000 project, in which metal rods pass through the reactor building to evacuate residual heat in the event of an accident. This configuration is used to reinforce the Emergency Injection Network (RIS) but is not configured to be used for a reactor operating at full power.

[0012] For example, patent US2018 / 075931 describes a molten salt reactor whose cooling circuit passes through the reactor core. This configuration presents a safety risk, particularly in the event of a cooling circuit failure.

[0013] In the present new and inventive application, the high-safety liquid metal and / or molten salt nuclear reactor operates at near-ambient pressure. The nuclear reactor transfers heat through heat-transfer fins, not integral with the reactor containment vessel or the safety vessel or the protective shell, outside the latter and / or without a thermo-syphon. The nuclear reactor can be operated for heating use and / or to produce electricity by a conventional or supercritical device.

[0014] Compared to current technologies in operation (REP, EPR, PWR), in the present invention the nuclear reactor requires fewer components (no primary circuit or circuit that crosses the reactor) and allows to increase the efficiency and safety. The present invention structurally allows to reduce the costs of investment, construction, maintenance, operation, fuel.

[0015] This invention is designed to meet the safety criteria defined for a fourth-generation nuclear reactor, capable of consuming nuclear fuel stored in the form of waste, and to ultimately ensure the energy sovereignty of a country such as France. Summary of the invention:

[0016] The present invention relates to the production of a liquid metal and / or molten salt nuclear reactor having certain advantages by eliminating most of the disadvantages of loop and through circuits and making it possible to significantly reduce the investment cost compared to current reactors.The present invention consists mainly of a high-safety nuclear reactor which may comprise a containment vessel, a nuclear reactor core housed inside the containment vessel, a neutron reflector spaced from the containment vessel and positioned between the core and the containment vessel, a fuel composed of a nuclear fission material dissolved in a liquid metal / or a molten salt which is the main constituent of the nuclear reactor core, a plurality of heat transfer heat exchanger fins, a possible heat exchanger external to the reactor to receive the heat transfer, at least one nuclear reactor shutdown system, a safety / safety retention vessel surrounding the containment vessel to recover the corium and thus provide another containment barrier, possibly a protective shell providing another containment barrier. Description of figures :

[0017] The liquid metal or alloy or molten salt nuclear reactor of the present invention will be better understood from the figures: [ fig 1 ] There figure 1 is a sectional view of one embodiment of the nuclear reactor in a normal operating state. fig 2 ] There figure 2 is a sectional view of another embodiment of the nuclear reactor in a normal operating state. fig 3 ] There figure 3 is a top view of one embodiment of the nuclear reactor in a normal operating state. fig 4 ] There figure 4 is a schematic view of one mode of use of the nuclear reactor. fig 5 ] There Figure 5 is a schematic view of another mode of use of the nuclear reactor. fig 6 ] There figure 6 is a top view of a heat transfer device under the reactor. Description of the invention:

[0018] The liquid metal or alloy or molten salt nuclear reactor can generate reliable, safe, and emission-free energy for the production of heat and electricity in decentralized sites. Decentralized emission-free energy production can complement or even exceed centralized electricity generation capacity, thus increasing the distribution and availability of clean and reliable energy at significant cost savings. Indeed, the fuel cost is reduced. The fuel is melted, so there is no need for a fuel fabrication plant, which can represent a significant saving, particularly in operation. For example, thorium is low cost, around €0.03 / MWh electric. Compared to uranium, at around €10 / MWh electric, thorium would be around 300 times cheaper.

[0019] The liquid metal or alloy or molten salt nuclear reactor has the potential to generate a much smaller quantity of very long-lived radioactive waste.

[0020] The liquid metal or alloy or molten salt nuclear reactor may eventually reduce the risk of nuclear weapons proliferation.

[0021] The liquid metal or alloy or molten salt nuclear reactor can potentially play a vital role in the deployment of a closed fuel cycle and reduce long-lived waste. The thorium nuclear cycle produces traces of uranium-232, when fast neutrons eject a neutron by (n, 2n) reaction of thorium-232 nuclei. Uranium-232 undergoes alpha decay and joins the thorium-228 decay chain. It should be noted that during this process, elements such as radium-224 emit significant gamma radiation.

[0022] The liquid metal or alloy or molten salt nuclear reactor can burn Uranium or Thorium or Plutonium and transform minor actinides, long-lived nuclear waste, into shorter-lived nuclear waste by transmutation. The ultimate waste is then limited to the fission products of minor actinides, which are easier to store. In this case, the radioactivity level is close to 300 years. Furthermore, by using stocks of depleted uranium and spent fuel from reactors currently installed on French territory, this nuclear reactor is capable of independently supplying energy to a country such as France for 500 years.

[0023] Given the high power density, it is possible to design and build a very small liquid metal or alloy or molten salt nuclear reactor for decentralized heat and / or electricity production outside the transmission grid.

[0024] It is possible to design and build a very small liquid metal or alloy or molten salt nuclear reactor for energy production on Earth, the Moon, or Mars. The dimensions and materials used for design and construction are specified for operation on Earth but can easily be adapted to each specific case.

[0025] It is also possible to have a small reactor core without very high enrichment. In addition, the neutronic behavior of molten fuel improves the control capability required for autonomous operation.

[0026] By design, the liquid metal or alloy or molten salt nuclear reactor can produce as much or more fissile material as it consumes. In other words, each time a fast neutron causes the fission of a plutonium-239 atom, other neutrons simultaneously transform uranium-238 into plutonium-239. The necessary condition for the continuous regeneration of plutonium is not to slow down the neutrons.

[0027] The liquid metal or alloy or molten salt nuclear reactor can operate differently depending on the uses: in generator (equality between production and consumption of fissile material) in sub-generator (net consumption of fissile material) to consume plutonium in breeder (production of plutonium greater than consumption).

[0028] The fuel is integrated into a liquid metal and / or molten salt and cooled by removing the heat outside the containment vessel of the liquid metal or alloy or molten salt nuclear reactor by heat transfer. It therefore incorporates a novelty and an innovation which aims to reinforce the safety of a basic nuclear installation.

[0029] The fuel used is in the form of a mixture of uranium 238 (approximately 80%) and plutonium (approximately 20%) or Thorium. The fuel is immersed in a liquid metal or molten salts. The liquid metal or molten salts serves as a coolant. The temperature in the core of the nuclear reactor is between 600°C and 800°C. The fuel transmits the calories created by fission to an external circuit via heat transfer fins in which a heat transfer fluid can circulate.

[0030] To meet safety requirements, a safety vessel / corium recovery vessel (molten core) is placed under / or around the containment vessel of the liquid metal or alloy or molten salt nuclear reactor to recover the corium in the event of a nuclear reactor core meltdown. The objective is to recover the corium, spread it out, cool it and confine the radioactivity.

[0031] A protective shell or other steel or concrete enclosure may serve as an additional containment barrier to increase the safety of the liquid metal or alloy or molten salt nuclear reactor.

[0032] A deterministic approach supplemented by a probabilistic approach makes it possible to consider almost all types of possible accidents even if the probability of the event occurring is low. The hypothesis of a severe accident is taken into account. The core geometry is designed to have a negative void coefficient, allowing the chain reaction to be stopped in a situation of loss of liquid metal, even in the hypothetical situation where no protection system would operate. Malicious acts are taken into account in the design, including the intentional crash of an aircraft.

[0033] The energy conversion system can use a gas (nitrogen) exchanger. The overall net efficiency of the reactor can be greater than 50%. Residual thermal power can be passively removed, in the event of loss of electrical sources, by gas / air exchangers, by natural convection.

[0034] The liquid metal or alloy or molten salt nuclear reactor does not need to be built near large waterways.

[0035] The liquid metal or alloy or molten salt nuclear reactor has a geometric configuration that allows the internal structures to be inspected.

[0036] The liquid metal or alloy or molten salt nuclear reactor can be operated for heating use and / or to produce electricity by a conventional or supercritical device.

[0037] The high-safety liquid metal or alloy or molten salt nuclear reactor is designed so that the fuel is cooled by liquid metal and / or molten salt.

[0038] The liquid metal or alloy or molten salt nuclear reactor is designed to operate at near ambient pressure.

[0039] The liquid metal or alloy or molten salt nuclear reactor is designed to transfer heat outside the core of the nuclear reactor by heat transfer fins not attached to the containment vessel of the nuclear reactor and without thermo-syphon.

[0040] The liquid metal or alloy or molten salt nuclear reactor is not limited to the few examples of embodiments described; on the contrary, it is susceptible to variations and modifications.

[0041] The liquid metal or alloy or molten salt nuclear reactor (1000) includes a nuclear thermal energy generation device from a few kW to a few MW thermal and can provide reliable, sustainable, flexible, safe energy at a moderate cost.

[0042] The liquid metal or alloy or molten salt nuclear reactor (1000) has its core housed in a containment vessel. The core of the liquid metal or alloy or molten salt nuclear reactor is the site of nuclear fission reactions and therefore the site of heat and radiation release. This design has several advantages, particularly from a safety perspective, since it ensures excellent containment of radioactive materials, high thermal inertia and relatively simple operation. Furthermore, it should be noted that with such a configuration, great latitude is possible for the calculation of thermal characteristics and heat exchanges, in particular everything concerning the dimensions of the pipes and heat transfer fins or the associated pressure drops. Under these conditions, the nuclear reactor is much easier to size and optimize to reduce the cost of an installation.

[0043] The liquid metal or alloy or molten salt nuclear reactor (1000) stabilizes itself. Indeed, when reactivity increases, the temperature rises. The strong thermal expansion of the liquid metal / fuel mixture pushes it out of the active region of the core when it heats up, thus decreasing its density in the active region of the core, and reducing the reactivity in the reactor. The temperature drops immediately. Conversely, when the liquid metal / fuel mixture cools, the density in the core increases, the probability of fission increases, as does the capacity to generate heat. These two effects give the reactor its character of stability, and allow it to follow the power demand (extraction of heat by the fins). The temperature of the reactor core and therefore the thermal power produced by the reactor, are thus regulated by the extraction of heat.

[0044] The liquid metal or alloy or molten salt nuclear reactor (1000) is designed for a long life.

[0045] The liquid metal or alloy or molten salt nuclear reactor (1000) does not require any planned maintenance.

[0046] The liquid metal or alloy or molten salt nuclear reactor (1000) allows autonomous energy production for decentralized needs.

[0047] The liquid metal or alloy or molten salt nuclear reactor (1000) comprises a modular nuclear reactor with a high degree of safety which incorporates safety criteria of the fourth generation of reactor.

[0048] The liquid metal or alloy or molten salt nuclear reactor (1000) includes a passive heat transport system.

[0049] The liquid metal or alloy or molten salt nuclear reactor (1000) comprises at least one shutdown system.

[0050] The liquid metal or alloy or molten salt nuclear reactor (1000) includes a safety / retention vessel, to recover the corium in the event of melting of the containment vessel.

[0051] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the reactor comprises a buffer tank of neutral gas and means for injecting said neutral gas into the gaseous ceiling for the purpose of compensating for variations in fuel volume.

[0052] In a liquid metal or alloy or molten salt (1000) nuclear reactor configuration, fission gases, such as helium, xenon, krypton and radon, are generated by the nuclear fission reaction in the reactor core. Volatile fission gases are toxic to reactors, especially to increase the reactor's useful life, so it is preferable to eliminate them. Also, it may be appropriate to install a device that will adsorb fission gases, such as molecular sieves, to trap and retain these gases to reduce the pressure of the vessel. In this case, the cooling of the molecular sieves can be achieved passively by the convective or heat transfer fins.

[0053] According to a liquid metal or alloy or molten salt nuclear reactor configuration (1000), the liquid metal / or molten salt is molten halide.

[0054] In a liquid metal or alloy or molten salt (1000) nuclear reactor configuration, fuel such as uranium oxyhalide is dissolved in the molten metal / or salt (1010).

[0055] In a liquid metal or alloy or molten salt (1000) nuclear reactor configuration, fuel such as UO 2 CI 2 / UO 4 / Plutonium / Thorium is dissolved in KC1 (1010).

[0056] In a liquid metal or alloy or molten salt (1000) nuclear reactor configuration, fuel such as UO 2 CI 2 / UO 4 / Plutonium / Thorium is dissolved in MgCi 2 (1010).

[0057] In a liquid metal or alloy or molten salt (1000) nuclear reactor configuration, the fuel such as UO 2 CI 2 / UO 4 / Plutonium / Thorium is dissolved in NaCl (1010).

[0058] In a liquid metal or alloy or molten salt (1000) nuclear reactor configuration, the fuel such as UO 2 CI 2 / UO 4 / Plutonium / Thorium is dissolved in an alkali or alkaline earth metal halide salt such as a mixture of sodium chloride, potassium chloride, magnesium chloride, calcium chloride (1010).

[0059] Depending on a liquid metal or alloy or molten salt (1000) nuclear reactor configuration, fluorides can also be used instead of chlorides.

[0060] Depending on a liquid metal or alloy or molten salt nuclear reactor configuration (1000), the fuel may be uranium chloride or uranium fluoride, uranium oxide or uranium oxyhalides, with possible mixtures of thorium halides and transuranic elements.

[0061] According to one configuration of the invention, the liquid metal or alloy or molten salt nuclear reactor (1000) is a liquid metal / molten salt fast reactor in which the liquid fuel is retained and is not pumped.

[0062] According to a configuration of the invention, the liquid metal or alloy or molten salt nuclear reactor (1000) is a thermal reactor in which moderators can be introduced into the core of the liquid metal or alloy or molten salt nuclear reactor.

[0063] According to one embodiment of the invention, the liquid metal or alloy or molten salt nuclear reactor (1000) is operatively coupled to a heat exchanger which is used to heat a fluid which may be a superheated gas or to generate steam for use in a steam turbine, to drive an alternator, similar to those of conventional water-cooled reactors. Such devices are well known in the power generation industry.

[0064] According to one embodiment of the invention, the liquid metal or alloy or molten salt nuclear reactor (1000) is used to directly heat a fluid which may be a superheated gas to drive a turbine, and / or an alternator. These devices are well known in the power generation industry.

[0065] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), a neutron mirror or reflector (1020) is arranged inside a containment vessel (1040).

[0066] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), a neutron mirror or reflector (1020) may be annular and have walls, a floor and a ceiling.

[0067] Depending on a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), a neutron mirror or reflector (1020) can be made of alumina oxide (Al 2 O 3 ), beryllium oxide (BeO), or beryllium carbide (Be 2 C).

[0068] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), a neutron mirror or reflector (1020) makes it possible to reflect the neutrons towards the core of the nuclear reactor, in order to improve the fission process, to stabilize the operating point of the liquid metal or alloy or molten salt nuclear reactor, to optimize the good distribution of neutron flux inside the liquid metal or alloy or molten salt nuclear reactor according to its geometric dimensions and the quantity of fuel desired to obtain the desired thermal power.

[0069] According to one configuration of the invention, the liquid metal or alloy or molten salt nuclear reactor (1000) is a fast reactor having a thick neutron mirror or reflector (1020) spaced from the inside of the walls of the containment vessel (1040).

[0070] According to one configuration of the invention, the liquid metal or alloy or molten salt nuclear reactor (1000) comprises a containment vessel (1040) having side walls, for example, in the form of a cylinder, a vessel floor / bottom and a vessel ceiling / cover.

[0071] According to a configuration of the invention, the liquid metal or alloy or molten salt nuclear reactor (1000) comprises a containment vessel floor / bottom (1200) and a containment vessel ceiling / cover (1100) which can be bolted in order to facilitate the assembly and disassembly of the containment vessel and also ensure good sealing.

[0072] According to one configuration of the invention, the liquid metal or alloy or molten salt nuclear reactor (1000) comprises a containment vessel ceiling / lid (1100) which comprises orifices for the rotary rods of the shutdown system and for the fission gas management system.

[0073] According to one configuration of the invention, the liquid metal or alloy or molten salt nuclear reactor (1000) comprises a containment vessel floor / bottom (1200) which comprises one or more orifices to facilitate the flow of corium into the safety / retention vessel (1060).

[0074] According to a configuration of the invention, the liquid metal or alloy or molten salt nuclear reactor (1000) the / a safety / retention vessel ceiling / cover (1060) comprises orifices for the rotating rods of the shutdown system and for the fission gas management system.

[0075] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), a containment vessel (1040) contains the core of the liquid metal or alloy or molten salt nuclear reactor and is the location of the nuclear fission reactions and therefore the location of the release of heat and radiation.

[0076] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), a containment vessel (1040) contains the fuel dissolved in the liquid metal / or molten salts, the reflector / mirror, the moderator, the rotating rods.

[0077] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), a containment vessel (1040) may be made of a structural material to satisfy the containment function. The material may also have good conductive properties. Examples of materials include stainless steel and other structural alloys that are good conductors.

[0078] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the containment vessel (1040) is sized to facilitate the fission process, stabilize the operating point of the liquid metal or alloy or molten salt nuclear reactor, optimize the good distribution of neutron flux according to the geometric characteristics and the quantity of fuel desired to obtain the desired thermal power.

[0079] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the containment vessel (1040) can be housed in a protective shell (1080) which serves as a containment barrier or external protection. The protective shell contributes to achieving a high level of safety.

[0080] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the containment vessel (1040) can be housed in a safety / retention vessel (1060) which serves as a containment barrier. The safety / retention vessel contributes to achieving a high level of safety.

[0081] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the safety / containment vessel (1060) can be housed in a protective shell (1080) which serves as a containment barrier or external protection. The protective shell contributes to achieving a high level of safety.

[0082] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), a protective shell (1080) may provide an alternative containment function against leakage of fission materials and radiation.

[0083] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), a protective shell (1080) can provide a secure barrier against external threats to the core of the liquid metal or alloy or molten salt nuclear reactor.

[0084] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), a protective shell (1080) may be made of concrete of an appropriate thickness or of a refractory material or of an appropriate structural metal which satisfies the desired functions.

[0085] According to a configuration of the invention, the cooling / or heat transfer of the liquid metal or alloy or molten salt nuclear reactor (1000) can be carried out passively by convective or conductive or heat-transfer fins (1050) between the containment vessel (1040) and the safety / retention vessel (1060), then by convective or conductive or heat-transfer fins (1070) between the safety / retention vessel (1060) and the protective shell (1080), then by convective or conductive or heat-transfer fins (1090) outside the protective shell (1080).

[0086] According to a configuration of the invention, the cooling / or heat transfer of the liquid metal or alloy or molten salt nuclear reactor (1000) can be carried out passively by convective or conductive or heat-transfer fins (1050) between the containment vessel (1040) and the protective shell (1080), then by convective or conductive or heat-transfer fins (1070) between the safety / retention vessel (1060) and the protective shell (1080), then by convective or conductive or heat-transfer fins (1090) outside the protective shell (1080).

[0087] Depending on a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the convective or conductive or heat-carrying fins (1050, 1070, 1090) may be made of stainless steel, copper, tungsten or heat pipe plates.

[0088] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the heat transfer fins (1090) may include fluid transfer tubes inside them and thus be traversed by a heat transfer fluid.

[0089] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the heat transfer fins (1090) traversed by a heat transfer fluid can be connected to a heat pipe.

[0090] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the heat transfer fins (1090) traversed by a heat transfer fluid contribute to obtaining a high level of safety.

[0091] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the convective or conductive or heat-carrying fins are similar to those known in the art and can be constructed in the same manner.

[0092] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the interior of the containment vessel or the holding vessel of the liquid metal or alloy or molten salt nuclear reactor and all other structures may be made from corrosion-resistant materials such as nickel or molybdenum steel alloys, ceramics, such as alumina or coated by a corrosion / erosion-resistant material, such as high-nickel steel, other metals or ceramics.

[0093] According to one configuration of the invention, the liquid metal or alloy or molten salt nuclear reactor (1000) is designed to adapt to the liquid state of the already molten fuel so that there is no risk of fuel melting as is the case when solid fuel can potentially melt at high temperatures in certain severe accident scenarios.

[0094] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the containment vessel (1040) is preferably made of a neutron-reflecting material such as alumina, which has a very high melting point of the order of 2000°C, and has very little chance of failure due to temperature.

[0095] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the ceiling of the containment vessel (1100) is preferably made with a material which has a very high melting point of the order of 2000°C.

[0096] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the floor of the containment vessel (1200) is preferably made of a material which has a very high melting point of the order of 2000°C. In this case, the floor of the containment vessel (1200) comprises a metal plate / metal plates (1300) and bolted to the floor with a melting point of the order of 1200°C which closes the orifice(s).

[0097] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the floor of the containment vessel (1200) is preferably made of a material which has a melting point of the order of 1200°C.

[0098] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the safety / retention vessel (1060) is preferably made of a material which has a very high melting point of the order of 2000°C, and has very little chance of failure due to temperature.

[0099] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the containment vessel ceiling (1100), the containment vessel floor (1200), the metal plate(s) (1300) and the bolts may be made of a structural material to satisfy the containment function. The material may also have good conductive properties. Examples of materials include stainless steel and other structural alloys that are good conductors.

[0100] According to one configuration of the invention, the liquid metal or alloy or molten salt nuclear reactor (1000) comprises at least one fusible shutter / or fusion plug which can be positioned to plug, under normal operating conditions, a passage in the wall of the neutron reflector and the containment vessel (1040) leading to a safety / retention vessel (1060) which is used to recover the corium.

[0101] According to one configuration of the invention, in the event that the heat transfer is not functioning properly or if there is a cause for an increase in the temperature of the core of the liquid metal or alloy or molten salt nuclear reactor, the shutter / plug / floor / bolted plate / plates of the containment vessel melt(s) in response to the predetermined temperature increase, draining the molten fuel to the safety / containment vessel (1060).

[0102] According to one configuration of the invention, the liquid metal or alloy or molten salt nuclear reactor (1000) comprises a reactor shutdown system.

[0103] According to a liquid metal or alloy or molten salt nuclear reactor configuration (1000), the liquid metal or alloy or molten salt nuclear fission reaction must start with a radioactive source.

[0104] According to a liquid metal or alloy or molten salt nuclear reactor configuration (1000), a neutron absorbing material may be used in the shutdown system in the form of absorbing spheres, such as boron carbide spheres.

[0105] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the safety / retention tank (1060) is located below the containment tank (1040).

[0106] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the safety / retention tank (1060) is located around the containment tank (1040).

[0107] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the safety / containment vessel (1060) includes heat dissipation elements that dissipate heat to cool the molten fuel. The safety / containment vessel (1060) serves to recover the corium, and allows the corium to cool. The safety / containment vessel (1060) contributes to achieving a high level of safety.

[0108] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the safety / retention tank (1060) serves as a containment barrier.

[0109] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the safety / retention tank (1060) may comprise by construction a neutron-absorbing material.

[0110] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the safety / containment vessel (1060) may include heat dissipation fins (not described) inside / under the protective shell to better cool the corium.

[0111] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the safety / containment tank (1060) comprises a containment tank floor / bottom (not described) and a containment tank ceiling / cover (not described) which can be bolted together in order to facilitate assembly and disassembly of the containment tank and also ensure a good seal.

[0112] Depending on a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), a safety / containment vessel (1060) may be made of a structural material to satisfy the containment function. The material may also have good conductive properties. Examples of materials include stainless steel and other structural alloys that are good conductors.

[0113] According to a configuration of the invention, the liquid metal or alloy or molten salt nuclear reactor (1000) comprises a shutdown system composed of several rotating rods and each rotating rod (1030) of which is made of absorbent materials used to control the fission reaction.

[0114] If the rotating rods of the shutdown system are turned so that their absorbing materials face the reactor core, neutrons from the fuel are absorbed into the absorbing material (e.g. boron carbide), causing the reactor to reach subcritical neutron levels, so that the nuclear reaction stops.

[0115] When the nuclear reactor is activated, the rotating rods (1030) of the shutdown system are gradually rotated to move the absorbent material. When the reactor reaches the desired power level, the rotation of the rotating rods (1030) is stopped.

[0116] When the fuel is exhausted, the rotating rods (1030) of the shutdown system reflect more neutrons back into the core of the nuclear reactor. When there is a buildup of fission products, the fission reaction stops and the nuclear reactor shuts down.

[0117] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the rotary rods (1030) of the shutdown system can be actuated by a non-detailed pneumatic device (2000) more efficient than electric motors, in particular in the event of a power outage.

[0118] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the rotary rod(s) (1030) of the shutdown system may be actuated by a non-detailed device (2000) composed of electric motors.

[0119] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), a gamma ray shield (not described) may be positioned outside the liquid metal or alloy or molten salt nuclear reactor to act as a protective shield for persons in the vicinity of the liquid metal or alloy or molten salt nuclear reactor.

[0120] According to one configuration of the invention, the liquid metal or alloy or molten salt nuclear reactor (1000) may have a double-walled protective shell (1080).

[0121] According to one configuration of the invention, the liquid metal or alloy or molten salt nuclear reactor (1000) may have a double-walled safety / retention tank (1060).

[0122] According to a configuration of the invention, under all normal or abnormal transient conditions, the liquid metal or alloy or molten salt nuclear reactor (1000) is designed to self-regulate in order to ensure the safety of property and people.

[0123] According to a configuration of the invention, the liquid metal or alloy or molten salt nuclear reactor (1000) is equipped with sensors (not described here) in order to optimize operation and ensure its safety.

[0124] According to a configuration of the invention, the liquid metal or alloy or molten salt nuclear reactor (1000) has a diameter of between 0.1 and 2 meters, and a height of between 0.2 and 2.5 meters.

[0125] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the containment vessel (1040) has a thickness between 0.02 and 0.5 meters and a height between 0.1 and 1 meter (calculated according to the thermal power delivered by the reactor and the safety rules recommended locally for operating a Basic Nuclear Installation).

[0126] Depending on the configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the safety / retention tank (1060) has a thickness of between 0.02 and 0.5 meters and a height of between 0.1 and 1 meter (calculated according to the thermal power delivered by the reactor and the safety rules recommended locally for operating a Basic Nuclear Installation).

[0127] Depending on the configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the protective shell (1080) has a thickness of between 0.1 and 0.5 meters and a height of between 0.1 and 2.5 meters (calculated according to the thermal power delivered by the reactor and the safety rules recommended locally for operating a Basic Nuclear Installation).

[0128] According to a liquid metal or alloy or molten salt (1000) nuclear reactor configuration, the operating temperature of the nuclear reactor is between 600 and 800 °C and the operating pressure is close to ambient pressure.

[0129] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), a plurality of heat transfer fins (1050, 1070, 1090) not welded to the containment and safety / retention vessels, or to the protective shell of the liquid metal or alloy or molten salt nuclear reactor transfer heat without thermo-syphon to the outside of the core of the liquid metal or alloy or molten salt nuclear reactor.

[0130] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the heat transfer fins (1050, 1070, 1090) have a thickness between 1 and 10 cm, a width between 5 and 50 cm, and a length which adapts according to the thickness of the protective shell (1080).

[0131] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the heat transfer fins (1050, 1070) touch the containment vessel (1040) but are not welded to it. This allows the containment vessel (1040) to be dismantled without difficulty.

[0132] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the heat transfer fins (1070, 1090) touch the safety / retention tank (1060) and the protective shell (1080) but are not welded to it. This allows the retention tank (1060) to be dismantled without difficulty.

[0133] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the plurality of heat transfer fins touch the containment vessel, the safety / retention vessel, the protective shell. The containment function is then ensured by contact between metals.

[0134] Depending on the configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), a ceramic layer (not described) may be partially installed between the safety / retention tank and the protective shell. The containment function is then ensured by contact between metals.

[0135] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the plurality of heat transfer fins (1070) is in contact with at least one external heat exchanger (not described here).

[0136] According to a configuration of the liquid metal or alloy or molten salt nuclear reactor (1000), the plurality of heat transfer fins (1090) is in contact with at least one heat exchanger external (not described here) to the protective shell in the case where the latter is implemented to provide another containment barrier.

[0137] In one possible configuration, the reactor transfers heat to supercritical carbon dioxide; this allows it to directly power a carbon dioxide turbine and an electrical generator, for example a high-speed generator.

[0138] In one possible configuration, the reactor can be placed above a heat transfer device in the ground, particularly in the event of an accidental meltdown of the containment vessel. This device makes it easier to cool the corium in the safety / retention vessel.

[0139] According to a possible configuration, the safety / retention tank after a temperature rise can be dismantled and cut into chips, for example by laser, and reused in another liquid metal or alloy or molten salt nuclear reactor.

[0140] According to one possible configuration, the entire containment vessel damaged after a temperature rise can be dismantled and cut into chips, for example by laser, and reused in another liquid metal or alloy or molten salt nuclear reactor.

[0141] According to a possible configuration, the containment vessel as a whole, undamaged after a temperature rise, can be reused in the liquid metal or alloy or molten salt nuclear reactor.

[0142] The present invention has been described with reference to various embodiments. As far as possible, one or more elements, components, constituents, structures, modules of the described embodiments may be combined, separated, interchanged, rearranged with one or more other elements, components, constituents, structures, modules of the embodiments without departing from the scope of the disclosed invention. The present invention is not limited by the description of the various embodiments. Those skilled in the art may obtain other ways of implementation from the technical solutions of the present invention.

Claims

1. Nuclear reactor (1000) operated, for heating use and / or to produce electricity by a conventional or supercritical device, outside the transport network, with a high level of safety, capable of consuming nuclear fuel stored in the form of waste integrated into a liquid metal, operates at near ambient pressure, transfers heat outside the core of the nuclear reactor by heat transfer fins not integral with the containment vessel of the nuclear reactor, and comprising: - a fuel in the form of a mixture of uranium, plutonium or Thorium, integrated into a liquid metal and / or molten salt (1010), preserved and not pumped and cooled by evacuation of the heat outside the containment vessel;- a neutron mirror (1020) allows neutrons to be reflected towards the core of the nuclear reactor, in order to improve the fission process, to stabilize the operating point of the liquid metal or alloy or molten salt nuclear reactor, to optimize the good distribution of neutron flux inside the reactor; - rotating rods (1030) of the shutdown system can be actuated by a pneumatic device which is more efficient than electric motors, in particular in the event of a power cut;- a containment vessel (1040) is sized to facilitate the fission process, stabilize the operating point of the liquid metal or alloy or molten salt nuclear reactor, optimize the good distribution of neutron fluxes according to the geometric characteristics and the quantity of fuel desired to obtain the desired thermal power, made of materials such as nickel steel alloys to satisfy the confinement function;- a plurality of heat transfer fins (1050, 1070, 1090) not integral with the containment vessel of the liquid metal or alloy or molten salt nuclear reactor, made of stainless steel, copper, tungsten or heat pipe plates, may have fluid transfer tubes inside them and thus be traversed by a heat transfer fluid, contribute to obtaining a high level of safety, the fins (1050) touch the containment vessel (1040) but are not welded to it, the fins (1070) touch the containment vessel (1040) and the retention vessel (1060) but are not welded to it, which allows the containment vessel (1040) and the retention vessel (1060) to be dismantled without difficulty; - a double-walled safety / retention tank (1060) is used to recover the corium, contributes to obtaining a high level of safety, serves as a containment barrier, and may include by construction a neutron-absorbing material;- a double-walled protective shell (1080) can provide a secure barrier against external threats.; 2. Nuclear reactor (1000) according to claim 1, the reactor has a diameter of between 0.1 and 2 meters, and a height of between 0.2 and 2.5 meters.

3. Nuclear reactor (1000) according to claims 1 to 2, the structures can be made from materials such as nickel or molybdenum steel alloys.

4. Nuclear reactor (1000) according to claims 1 to 3, the fuel such as UO2CI2 / UO4 / Plutonium / Thorium is dissolved in KC1 (1010).

5. Nuclear reactor (1000) according to claims 1 to 3, the fuel such as UO2CI2 / UO4 / Plutonium / Thorium is dissolved in MgCi2 (1010).

6. Nuclear reactor (1000) according to claims 1 to 3, the fuel such as UO2CI2 / UO4 / Plutonium / Thorium is dissolved in NaCl (1010).

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