241results about "Fast fission reactors" patented technology

A nuclear reactor in which a secondary or tertiary coolant system of a nuclear steam supply system is simplified, comprising: a reactor vessel (2) which integrates a reactor core (1); a first coolant (3) which is stored in the reactor vessel (2) and heated by the reactor core (1) to convect; a first heat transfer tube (4) which is arranged in the reactor vessel (2) and comes into contact with the first coolant (3); and a second coolant (5) which is supplied from the outside of the reactor vessel (2) to the first heat transfer tube (4), cools the first coolant (3) and led to the outside of the reactor vessel (2).

A nuclear reactor (1) is provided, in particular a nuclear reactor cooled with a liquid metal (for example, a heavy liquid metal, such as lead or lead-bismuth eutectic), of the type having a cylindrical inner vessel (15) that divides a hot collector (6) over a core (4) from a substantially annular cold collector (7) surrounding the hot collector; housed in the cold collector (7) is a plurality of integrated circulation and heat-exchange assemblies (20), each of which includes a pump (9), two heat exchangers (10) set at the sides of the pump, and a conveying structure (21) through which a primary fluid (8) for cooling the core passes from the pump to the heat exchanger, all of which are fixedly connected to one another to form a unitary structure; each integrated assembly has an inlet (26) connected to the hot collector (6) and two outlet sections (34) in the cold collector (7).

This disclosure describes nuclear fuel salts usable in certain molten salt reactor designs and related systems and methods. Binary, ternary and quaternary chloride fuel salts of uranium, as well as other fissionable elements, are described. In addition, fuel salts of UClxFy are disclosed as well as bromide fuel salts. This disclosure also presents methods and systems for manufacturing such fuel salts, for creating salts that reduce corrosion of the reactor components and for creating fuel salts that are not suitable for weapons applications.

A light water reactor to safely convert depleted uranium into a fuel source that could be used as a sustainable source of energy for centuries. The reactor is a type of breed-burn reactor uniquely combined with a proliferation-resistant fuel cycle with no uranium enrichment and no plutonium isolation. It is comprised of a compact factory-produced fast region and a thermal region that produces about 95% of the core power and contains the passageways for transports of delayed-neutron emitters to the fast region, where they can provide additional neutrons (source-based mode) or all the necessary excitation without an external neutron source (self-regulating mode). A second embodiment of the invention is a small unit driven by a neutron source with beam recycling for propulsion, electrical power or radioisotope production. It could also serve as a demonstration facility for the transmutation reactor with fission-fusion fuel.

A molten salt reactor is described that includes a containment vessel, a reactor core housed within the containment vessel, a neutron reflector spaced from the containment vessel and positioned between the core and the containment vessel, a liquid fuel comprised of a nuclear fission material dissolved in a molten salt enclosed within the core, a plurality of heat transfer pipes, each pipe having a first and a second end, wherein the first end is positioned within the reactor core for absorbing heat from the fuel, a heat exchanger external to the containment vessel for receiving the second end of each heat transfer pipe for transferring heat from the core to the heat exchanger, and at least one and preferably two or more reactor shut down systems, where at least one may be a passive system and at least one or both may be an active or a manually operated system. The liquid fuel in the core is kept within the core and heat pipes are used to carry only the heat from the liquid core to the heat exchanger.

The invention relates to a novel architecture for a nuclear reactor of the integrated type.The invention comprises:realising the hot area and cold area separation device for the primary sodium flow in the form of two walls with cuts,providing two pumping groups hydraulically in series, one for the flow of sodium from the hot area to the cold area through the intermediate exchangers and the other in the cold area;providing outlet windows of the intermediate exchangers below the lower wall;providing outlet windows of the removal exchangers of the decay heat above the cold area, wherein all of clearances between the walls with cuts and the heat removal exchangers and the height between the two walls with cuts are previously determined so as to, during normal operation, take up differential movements between the walls, exchangers and vessel and to make it possible to establish during normal operation a thermal stratification of the primary sodium in the space defined between the horizontal portions of the two walls and so as to reduce, in case of an unexpected stop of a single pumping group, the mechanical stress applied to the walls and due to the portion of the primary sodium flow passing between said clearances.

Disclosed herein is a fully passive decay heat removal system utilizing a partially immersed heat exchanger, the system comprising: a hot pool; an intermediate heat exchanger which heat-exchanges with the sodium of the hot pool; a cold pool; a support barrel extending vertically through the boundary between the hot pool and the cold pool; a sodium-sodium decay heat exchanger received in the support barrel; a sodium-air heat exchanger provided at a position higher than the sodium-sodium decay heat exchanger; an intermediate sodium loop connecting the sodium-sodium decay heat exchanger with the sodium-air heat exchanger; and a primary pump, wherein a portion of the effective heat transfer tube of the sodium-sodium decay heat exchanger is immersed in the cold pool, particularly in a normal operating state, and the surface of the lower end of a shroud for the sodium-sodium decay heat exchanger, the lower end being immersed in the sodium of the cold pool, has perforated holes.

A decay heat removal system for a liquid metal reactor, in which a decay heat exchanger (DHX) is installed concentrically with an intermediate heat-exchanger (IHX) in the same cylinder which separates the DHX and IHX from the reactor pool fluid, and serves to remove the reactor core decay heat. The cylinder surrounds the IHX and the DHX, and has an opened top portion protruded out of the level of the fluid in a hot pool, a bottom portion connected to a cold pool and a guide pipe for allowing the passage of the fluid from the hot pool into the IHX. The decay heat removal system can remove decay heat immediately after occurrence of an accident, thereby improves the safety of a nuclear plant.

Dis0closed herein is a direct pool cooling type passive safety grade decay heat removal method and system for removing core decay heat in a pool type liquid metal reactor when a normal heat removal system breaks down. In the liquid metal reactor comprising a reactor vessel, the interior of which is partitioned into a hot pool above a core and a cold pool around the core so that liquid level difference between the hot pool and the cold pool is maintained by a primary pumping head under normal steady-state conditions, is disposed at least one circular vertical tube in such a manner that the sodium in the circular vertical tube is maintained with the same liquid level as the liquid level of the sodium in the cold pool. In the circular vertical tube is disposed a sodium-sodium heat exchanger, which is connected to a sodium-air heat exchanger mounted above a reactor building via a heat removing sodium loop, in such a manner that it is placed at the position higher than a liquid level of the sodium in the cold pool under the normal steady-state conditions. Under transient conditions, for example, when the normal heat removal system breaks down, the primary pump is automatically tripped, and accordingly the liquid level of the cold pool rises with the result that the liquid level difference between the hot pool and the cold pool is eliminated. Consequently, the sodium-sodium heat exchanger makes direct contact with the hot sodium so that core decay heat is discharged into a final heat sink, for example, the atmosphere. In this way, the decay heat removal system of the present invention is operated on the basis of a completely passive concept with improved operational reliability. Heat loss incurred by the decay heat removal system is minimized under normal steady-state conditions, whereby economical efficiency is maximized. The decay heat removal system of the present invention can effectively remove core decay heat under transient conditions. Moreover, the decay heat removal system of the present invention provides an additional heat removal capacity obtained by the passive vessel cooling system, whereby the decay heat removal system of the present invention can be easily applied to a large thermal rated liquid metal reactor.

An accelerator-driven subcritical breeding reactor is operated with a neutron multiplication coefficient as large as possible in order to require a small input power from the accelerator, reducing its dimension and hence its cost and complexity. The beam-generated spallation neutron yield then becomes comparable to the fraction of delayed neutrons from the fissioned elements. This can be exploited to ensure an accurate on-line determination of the reactivity. Resulting changes can be adjusted with the help of neutron absorbing control rods and / or variations of the proton current. In addition, the temperature variations during operation can be continuously monitored and adjusted in order to avoid that the subcritical systems approaches too closely the (delayed) criticality condition and that the neutron multiplication coefficient remains within acceptable limits.

This disclosure describes nuclear fuel salts usable in certain molten salt reactor designs and related systems and methods. Binary, ternary and quaternary chloride fuel salts of uranium, as well as other fissionable elements, are described. In addition, fuel salts of UClxFy are disclosed as well as bromide fuel salts. This disclosure also presents methods and systems for manufacturing such fuel salts, for creating salts that reduce corrosion of the reactor components and for creating fuel salts that are not suitable for weapons applications.

The invention relates to a novel architecture for a nuclear reactor of the integrated type. The invention comprises: realising the hot area and cold area separation device for the primary sodium flow in the form of two walls with cuts, providing two pumping groups hydraulically in series, one for the flow of sodium from the hot area to the cold area through the intermediate exchangers and the other in the cold area; providing outlet windows of the intermediate exchangers below the lower wall; providing outlet windows of the removal exchangers of the decay heat above the cold area, wherein all of clearances between the walls with cuts and the heat removal exchangers and the height between the two walls with cuts are previously determined so as to, during normal operation, take up differential movements between the walls, exchangers and vessel and to make it possible to establish during normal operation a thermal stratification of the primary sodium in the space defined between the horizontal portions of the two walls and so as to reduce, in case of an unexpected stop of a single pumping group, the mechanical stress applied to the walls and due to the portion of the primary sodium flow passing between said clearances.

The subject of the present invention is to provide a nuclear reactor plant of which is a direct cycle nuclear reactor using a carbon dioxide as a coolant such that a heat evacuation for liquefying coolant is reduced while a compressive work is reduced by using a condensation capability of a carbon dioxide for enhancing a cycle efficiency.The nuclear reactor plant is comprised of a nuclear reactor 1, a turbine 2, and wherein, the coolant of supper critical state is heated by a heat of a nuclear reactor to directly drive a turbine, a gaseous coolant discharged from said turbine is chilled and compressed after said turbine is driven for keeping in a critical state, and then said coolant is circulated again into said nuclear reactor, and wherein, a carbon dioxide is used as said coolant, and a predetermined ratio of gaseous coolant discharged from said turbine is liquefied for being compressed in a liquid state while a rest of gaseous coolant is compressed in a gaseous state.

A system, method and apparatus for demodulating a received signal using a configurable receiver. The receiver performs the demodulation of a signal according to a selected interference cancellation demodulation scheme. The same receiver can be configured, by setting certain parameters, to behave as a successive interference cancellation (SIC) scheme receiver, a parallel interference cancellation (PIC) scheme receiver, or a hybrid interference cancellation (HIC) scheme receiver. In another aspect of the present invention, the receiver performs its demodulation operation using a single interference cancellation unit (ICU). In addition, the ICU's despreading and respreading functions may be performed by the same processing element.

The invention discloses a method and a device for fast multiplicating and transforming nuclear fuel with high inherent security and low cost, and the method and the device adopt 'moving solid nuclear fuel' which can flow and is similar to fluid, can be applied in a fast neutron reactor, and produce more nuclear fuel with less fissile fuel initial installation quantity and lower cost in a shorter time, thus satisfying the nuclear fuel demand at the current world nuclear power big development stage. The method and the device for fast multiplicating and transforming nuclear fuel are real nuclear reactors with inherent security, and can thoroughly eliminate the serious accident of massive radioactive release caused by element melting of the nuclear fuel which still possibly occurs in the current nuclear power station.

A reactivity control rod adapted to be used in a reactor core of a fast reactor and disposed at a substantially central portion of the reactor core for controlling a reactivity therein. The reactivity control rod includes a wrapper tube surrounded by a plurality of fuel rods in a reactor core, and a plurality of neutron absorber rods arranged in the wrapper tube. At least one of the plurality of neutron absorber rods includes a cladding tube and a mixture filled in the cladding tube. The mixture is composed of a neutron absorber that absorbs a neutron and a neutron moderator that moderates the neutron.

This disclosure describes various configurations and components of a molten fuel fast or thermal nuclear reactor for managing the operating temperature in the reactor core. The disclosure includes various configurations of direct reactor auxiliary cooling system (DRACS) heat exchangers and primary heat exchangers as well as descriptions of improved flow paths for nuclear fuel, primary coolant and DRACS coolant through the reactor components.

The invention belongs to the field of cladding designs of a fusion and fission hybrid reactor, and particularly relates to a Th-U self-sustaining circulating full fused salt fuel hybrid reactor system and an operation method thereof. The Th-U self-sustaining circulating full fused salt fuel hybrid reactor system is characterized in that a fast fission breeder reactor provides an initial easily fission fuel required by starting of a thermal fission reactor, a cladding design of the thermal fission reactor utilizes an arrangement strategy of a seed-cladding to improve the entirety neutron economy of the system, and the purposes of a high energy enlargement factor of the system, tritium breeding and thorium-uranium self-sustaining circulating of the system are realized; <233>U is loaded in an energy generating region, so that the energy generating region has a good neutronics property and is mainly used for realizing the purposes of energy amplification of the system, neutron multiplication and most <233>U breeding of the system; superfluous neutrons enter a tritium producing region and are used for tritium breeding and part of <233>U breeding of the system. According to the hybrid reactor, due to self-sustaining circulating of thorium and uranium, a thorium fuel is converted into <233>U and is gradually burn up in an operation process, and the Th-U self-sustaining circulating full fused salt fuel hybrid reactor system can effectively and stably operate for a long time just by gradually adding the thorium fuel and removing the generated fission product.

A fast reactor having a reactivity control reflector has a reactor vessel in which a coolant is accommodated, a reactor core which is installed in the reactor vessel and dipped with the coolant, and a reflector installed outside of the reactor core so as to be movable in a vertical direction for controlling the reactivity of the reactor core. The reflector of the fast reactor has a lower neutron reflecting portion having a neutron reflection capability higher than that of the coolant and an upper cavity portion located above the neutron reflecting portion and having a neutron reflection capability lower than that of the coolant. The cavity portion is composed of a plurality of cylindrical hermetically-sealed vessels.

Configurations of molten fuel salt reactors are described that include an auxiliary cooling system which shared part of the primary coolant loop but allows for passive cooling of decay heat from the reactor. Furthermore, different pump configurations for circulating molten fuel through the reactor core and one or more in vessel heat exchangers are described.

The present nuclear reactor with a liquid metal coolant comprises a housing (1) having a separating shell (6) disposed therein. In the annular space (5) between the housing and the separating shell are disposed at least one steam generator (3) and at least one pump (4). Inside the separating shell (6) there is an active region (2), above which a heat collector (8) is disposed which is in communication with the vertically central portion of the steam generator (3) in order to separate a stream of liquid metal coolant into ascending and descending flows, or the heat collector (8) is in communication with the upper portion of the steam generator in order to create a counter-flow heat exchange regime. Below the reactor head is an upper horizontal cold collector (10) with an unfilled level of coolant, and below the steam generator (3) is a lower accumulating collector (11) in communication with the upper cold collector (10). The inlet of the pump (4) is connected to the upper cold collector (10), and the outlet of the pump (4) is connected to a lower annular pressure collector (12), wherein collectors (11) and (12) are separated by a horizontal partition (13), and collector (12) is in communication with a distributing collector (15) of the active region.

Provided is a high-accuracy fast neutron reactor assembly few-group cross section obtaining method. The fine-group cross section of a fast neutron reactor assembly is calculated in the mode that point cross section data and multi-group data are combined, online calculation of an elastic scattering matrix is performed, a neutron transport equation is solved by using the fine-group cross section to obtain fine-group neutron-flux density, energy groups are merged on the basis, and accordingly few-group parameters of the fast reactor assembly are obtained. Due to the fact that the method directly uses the point cross section data, the elastic scattering resonance effect of a medium mass nuclide and the resonance interference effects of all nuclides are accurately considered. The neutron-flux density of a real system is adopted in the energy group merging process, and merging results are more accurate. The overall errors of fast reactor assembly few-group parameters calculated by adopting the method are within 1% compared with a reference value, and the method has higher accuracy.

The invention relates to the field of nuclear engineering and can be used in the manufacture of fuel rods and fuel assemblies for heavy liquid metal cooled reactors, and also in the manufacture of fuel rod simulators for use in irradiation devices designed to test the operability of real fuel assemblies. The present cladding of a fuel rod for a heavy liquid metal cooled reactor is in the form of a weldless tubular element with helically-coiled fins disposed on the outer surface of said element, which is made from a ferritic-martensitic chromium-silicon steel with a minimum ferrite grain size of 7 on the GOST 5639 scale, wherein each fin has an opening angle of from 22 to 40 DEG C (preferably from 30 to 40 DEG C) and the cross-section of the fin is in the shape of a trapezoid with rounded corners at the top of the trapezoid and smooth corners at the base of the trapezoid. Also disclosed are a fuel rod comprising the above cladding, and a fuel assembly. The technical result of the invention is an improvement in the performance characteristics of fuel rods and assemblies as a result of the long-term resistance of the cladding in the environment of a heavy liquid metal coolant such as lead or a eutectic of lead and bismuth.

A liquid-metal cooled fast reactor core having a nuclear fuel assembly constituted of nuclear fuel rods with varying cladding thicknesses in reactor core regions, in which: the nuclear fuel assembly (1) of a liquid-metal cooled fast reactor includes nuclear fuel assemblies (1a, 1b and 1c) in inner, middle and outer reactor core regions, respectively, and is installed in a hexagonal duct (3) with nuclear fuel materials (2-2a, 2-2b and 2-2c) surrounded by respective claddings (2-1a, 2-1b and 2-1c), and the claddings (2-1a, 2-1b and 2-1c) of a nuclear fuel rod (2a) in the inner reactor core region, a nuclear fuel rod (2b) in the middle reactor core region and a nuclear fuel rod (2c) in the outer reactor core region are formed at different thicknesses. The reactor core can flatten power distribution using a single-enrichment nuclear fuel in the liquid-metal cooled fast reactor.

A 17×17 jacketless fuel assembly for a PWR-type light-water reactor uses thorium as the fuel. The fuel assembly has a square shape in the plan view, a seed region, a blanket region that encircles it, an upper nozzle, and a lower nozzle. The fuel elements of the seed region re arranged in the rows and columns of a square coordinate grid and have a four-lobed profile that forms spiral spacer ribs along the length of a fuel element. The blanket region contains a frame structure within which a bundle of fuel elements made from thorium with the addition of enriched uranium is positioned. The blanket region fuel elements are arranged in the two or three rows and columns of a square coordinate grid.

The invention discloses a reactor core supporting structure of a pool-typed sodium-cooled fast reactor. The reactor core supporting structure of the invention comprises a large grid-plate header, a small grid-plate header and a reactor core support barrel, which results in that the number of opening of the large grid-plate header and the structural complexity of the large grid-plate header are both greatly reduced and the entire rigidity of the reactor core supporting structure is also improved. In addition, the small grid-plate header which is split can more easily achieve the distribution of the flow required by different reactor core components.

[Problem] To build a secure and high-efficiency power generation system while achieving a further reduction in the size of the entire system. [Solution] A compact nuclear power generation system is provided with a reactor (3) comprising a core (2) which uses metal fuel containing either or both of uranium-235 / 238 and plutonium-239, a reactor vessel (1) which houses the core (2), metal sodium which is filled into the reactor vessel (1) and heated by the core (2), and a neutron reflector (9) which maintains the effective multiplication factor of neutrons emitted from the core (2) at approximately one or more to bring the core into a critical state. A main heat exchanger (15) is installed outside the reactor (3). The metal sodium heated by the reactor (3) is supplied to the main heat exchanger (15), and supercritical carbon dioxide that is subjected to heat exchange with the heated metal sodium circulates therethrough. The supercritical carbon dioxide heated by the main heat exchanger (15) drives a turbine (20), and a power generator (21) is operated by the drive of the turbine (20).