CN114093529A - Molten salt fast reactor - Google Patents

Molten salt fast reactor Download PDF

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Publication number
CN114093529A
CN114093529A CN202111249954.2A CN202111249954A CN114093529A CN 114093529 A CN114093529 A CN 114093529A CN 202111249954 A CN202111249954 A CN 202111249954A CN 114093529 A CN114093529 A CN 114093529A
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transmutation
molten salt
fast reactor
fuel
wall
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李晓晓
陈金根
邹杨
蔡翔舟
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Shanghai Institute of Applied Physics of CAS
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Shanghai Institute of Applied Physics of CAS
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    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21C—NUCLEAR REACTORS
    • G21C3/00—Reactor fuel elements and their assemblies; Selection of substances for use as reactor fuel elements
    • G21C3/30—Assemblies of a number of fuel elements in the form of a rigid unit
    • G21C3/32—Bundles of parallel pin-, rod-, or tube-shaped fuel elements
    • G21C3/336—Spacer elements for fuel rods in the bundle
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21C—NUCLEAR REACTORS
    • G21C3/00—Reactor fuel elements and their assemblies; Selection of substances for use as reactor fuel elements
    • G21C3/30—Assemblies of a number of fuel elements in the form of a rigid unit
    • G21C3/32—Bundles of parallel pin-, rod-, or tube-shaped fuel elements
    • G21C3/324—Coats or envelopes for the bundles
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00—Energy generation of nuclear origin
    • Y02E30/30—Nuclear fission reactors

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  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • General Engineering & Computer Science (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Monitoring And Testing Of Nuclear Reactors (AREA)

Abstract

The invention discloses a molten salt fast reactor. The molten salt fast reactor comprises an active region wall and an active region positioned inside the active region wall; the active region comprises a transmutation rod and a fuel salt region, wherein a containing space is arranged in the transmutation rod, and the fuel salt region is used for containing fuel salt; the transmutation rods are arranged in the fuel salt region, and the transmutation rods are arranged in the middle of the active region; the ratio of the equivalent diameter of the middle part to the equivalent diameter of the active area is 0.6-0.9. The molten salt fast reactor has high transmutation amount, low delayed neutron loss and high reactor core safety.

Description

Molten salt fast reactor
Technical Field
The invention relates to a molten salt fast reactor.
Background
Spent fuel is irradiated, used, but unburnt nuclear fuel. For the commercial pressurized water reactor that is currently in the mainstream, the radioactive toxicity of the spent fuel is mainly contributed by transuranic nuclides (TRUs) after 100 years of discharge from the core. Transmutation TRUs can greatly reduce the radioactive toxicity of spent fuel and significantly improve nuclear fuel utilization. Because the TRU has a large fission capture ratio under a fast neutron spectrum, and the transmutation TRU needs to consume a large amount of high-energy neutrons, the TRU is more suitable for adopting a fast reactor transmutation device, such as an accelerator-driven subcritical system (ADS) with the fast neutron spectrum, a solid-state critical fast reactor (such as a sodium-cooled fast reactor, a lead-cooled fast reactor and a gas-cooled fast reactor), and the like. In order to further improve the TRU transmutation capability of the fast reactor transmutation device, the loading capacity of the TRU is increased or the operation period of the transmutation device is prolonged. However, high loading of TRU elements can significantly reduce the core safety characteristics of solid fuel transmutation devices, and increasing the operational cycle of the transmutation devices can increase core safety control requirements or accelerator specifications, thereby limiting TRU transmutation capabilities.
As a liquid fuel reactor, the molten salt fast reactor is expected to solve the technical challenge of efficient transmutation TRU in a solid transmutation device. The density effect of the liquid fuel salt can compensate the weakening of temperature negative feedback caused by the high loading capacity of the TRU, and meanwhile, the online post-treatment and the online feeding enable the molten salt fast reactor to prolong the core operation period on the premise of not needing higher initial residual reactivity, thereby reducing the control requirement and improving the transmutation capability. However, the carrier salt of the current molten salt fast reactor is generally fluorine salt or chlorine salt, and the TRU has low solubility in the fluorine salt and the chlorine salt, and the solubility is respectively 30% (such as FLiNaK) and 45% (such as NaCl), which limits the TRU transmutation capability of the molten salt fast reactor to a certain extent. In addition, the flow of the liquid fuel salt causes the loss of delayed neutrons, and the safety of the molten salt fast reactor is weakened.
Disclosure of Invention
The invention provides a molten salt fast reactor for solving the technical problems that in the prior art, the solubility of transuranic elements in carrier salt is low, so that the transmutation capability is low, the slow neutron loss is large and the like. The molten salt fast reactor has high transmutation amount, low delayed neutron loss and high reactor core safety.
The invention solves the technical problems through the following technical scheme.
The invention provides a molten salt fast reactor, which comprises an active region wall and an active region positioned inside the active region wall;
the active region comprises a transmutation rod and a fuel salt region, wherein a containing space is arranged in the transmutation rod, and the fuel salt region is used for containing fuel salt;
the transmutation rods are arranged in the fuel salt region, and the transmutation rods are arranged in the middle of the active region;
the ratio of the equivalent diameter of the middle part to the equivalent diameter of the active area is 0.6-0.9.
In the present invention, the material of the active zone wall may be conventional in the art, and is preferably one or more of a nickel-based alloy, a molybdenum-rhenium alloy, and a niobium-zirconium alloy, and more preferably a nickel-based alloy.
In the present invention, preferably, the active zone wall includes an upper wall, a side wall, and a lower wall.
Wherein, preferably, the thickness of the upper wall is 1-3 cm; the thickness of the side wall is 1-5 cm; the thickness of the lower wall is 1-3 cm.
Wherein, preferably, the upper wall is conical with radian; the lower wall is conical with a curvature.
Wherein, preferably, the center of the upper wall is provided with a fuel salt outlet; the center of the lower wall is provided with a fuel salt inlet. The fuel salt inlet is preferably cylindrical; the fuel salt outlet is preferably cylindrical.
Preferably, the active region wall further comprises an upper chamber therein, the upper chamber is located between the active region and the upper wall, and the bottom of the upper chamber is communicated with the active region. The height of the upper chamber is preferably 1-20 cm.
Preferably, the active region wall further comprises a lower chamber therein, the lower chamber is located between the active region and the lower wall, and the top of the lower chamber is communicated with the active region. The height of the lower chamber is preferably 1-20 cm.
More preferably, a flow guide plate is arranged between the active area and the upper chamber and/or between the active area and the lower chamber. The deflector is preferably provided with a groove and an aperture, the shape and size of the groove are the same as the cross section of the transmutation rod, the groove is used for fixing the transmutation rod in the fuel salt area, and the aperture is used for communicating the active area and the upper chamber, and/or the active area and the lower chamber, thereby realizing the circulation of the fuel salt. The thickness of the guide plate is preferably 1-5 cm. The material of the flow guide plate is preferably one or more of nickel-based alloy, molybdenum-rhenium alloy and niobium-zirconium alloy, and more preferably nickel-based alloy. Preferably, the material of the baffle and the active zone wall is the same.
In the present invention, preferably, the periphery of the active region wall is provided with a reflective layer and a stack container.
The material of the reflective layer may be conventional in the art, and is preferably graphite, beryllium or beryllium oxide, and more preferably beryllium oxide.
Wherein, preferably, the thickness of the reflecting layer is 15-60 cm.
The material of the stack container may be conventional in the art, and is preferably one or more of a nickel-based alloy, a molybdenum-rhenium alloy and a niobium-zirconium alloy, and more preferably a nickel-based alloy.
Wherein, preferably, the thickness of the stack container is 2-10 cm.
In the present invention, the equivalent diameter of the active region means the diameter of a circle having an equal actual cross-sectional area of the active region, as known to those skilled in the art. The equivalent diameter of the middle portion means the diameter of a circle having an equal actual cross-sectional area of the middle portion.
In the present invention, the active region preferably has an equivalent diameter of 80 to 300 cm.
In the present invention, preferably, the active region has a cylindrical shape.
In the present invention, preferably, the ratio of the height of the active region to the equivalent diameter of the active region is 0.5 to 2.5.
In the present invention, preferably, the active region consists of a transmutation rod and a fuel salt region. At this time, the space enclosed by the inner wall of the active region and the outer wall of the transmutation rod is the fuel salt region.
In the present invention, the transmutation rods can be transmutation rods conventional in the art. For example, the transmutation performance of minor actinide nuclide in a lead-cooled fast reactor [ J ]. isotope, 2019,32(1):8., Huwen super-class, etc., the transmutation characteristic of the minor actinide nuclide in a large-scale advanced pressurized water reactor [ J ]. intense laser and particle beam, 2017,29(003):84-89., Huwen super-class, etc., the transmutation rod reported in the documents of preparing 238Pu based on the evolution 237Np of an AP1000 type reactor [ J ]. nuclear safety, 2017,016(004):78-83, etc. As known to those skilled in the art, the transmutation rods are generally used in solid fuel reactors (such as pressurized water reactors, lead-cooled fast reactors, sodium-cooled fast reactors, gas-cooled fast reactors, etc.) or liquid fuel reactors (such as molten salt thermal reactors). The transmutation rod generally contains long-life high-level nuclear waste which can be changed into non-radioactive nuclides or short-life nuclides through neutron nuclear reaction so as to realize nuclear waste minimization; the long-life high-level nuclear waste is generally transuranic and/or long-life fission products.
Wherein the receiving space within the transmutation rod is a transmutation zone, the receiving space preferably being for filling with transuranic oxides, transuranic nitrides or transuranic carbides.
Wherein, preferably, the transmutation rod comprises the accommodating space, an intermediate layer and an enclosure from inside to outside, and the accommodating space, the intermediate layer and the enclosure are coaxially arranged; the intermediate layer is a neutron poison layer or a fission product layer.
Wherein, preferably, the transuranic oxide in the accommodating space is TRUO2(ii) a The transuranic nitride in the accommodating space is TRUN; the transuranic carbide in the accommodating space is TRU3C2、TRUCxWherein x is 0.6-0.92, TRU2C3Or TRUC2(ii) a TRU is an isotope of neptunium ((r))237～238Np), isotopes of plutonium (238～242Pu), americium isotopes (b)241 ～244Am) and the isotopes of curium (a)242～248Cm) of the substrate.
Preferably, the equivalent radius of the accommodating space is 1-10 cm.
Wherein the neutron poison in the neutron poison layer can be a neutron poison conventional in the art, preferably boron and compounds thereof, europium and compounds thereof, gadolinium and compounds thereof or samarium and compounds thereof, and more preferably samarium and compounds thereofGd2O3。
Wherein the fission product in the fission product layer may be a long-life fission product conventional in the art, preferably one or more of Se, Sr, Zr, Nb, Tc, Pd, Sn, I, Cs, and Sm.
Wherein, preferably, the material of the intermediate layer is not a proliferation material, which results in poor TRU transmutation effect. Wherein said proliferative material is a proliferative material conventional in the art, such as a compound of thorium, more specifically such as ThO2、ThC2Or Th3N4。
Wherein, preferably, the thickness of the middle layer is 2-20 cm.
Wherein, the material of the cladding can be a high temperature resistant, radiation resistant and corrosion resistant material which is conventional in the field, and is preferably one or more of silicon carbide, carbon-carbon composite material, nickel-base alloy, molybdenum-rhenium alloy and niobium-zirconium alloy.
Wherein, the thickness of the cladding is preferably 1-10 cm.
Preferably, a heat insulation layer is arranged between the intermediate layer and the cladding, and the material of the heat insulation layer is gas (such as helium and the like) or solid (such as 8YSZ (8 mol% Y)2O3-92mol％ZrO2)、ZrO2、Al2O3Or SiO2Etc.), the thickness of insulating layer is 1 ~ 5 mm.
In the present invention, the shape of the transmutation rod can be conventional in the art, preferably the cross-section of the transmutation rod is circular, hexagonal or quadrilateral.
In the present invention, preferably, the transmutation rods are arranged in the fuel salt region in a triangular grid, a quadrilateral grid or along a circumference, and more preferably, the transmutation rods are arranged in the fuel salt region in a regular triangular grid. Wherein the quadrilateral grid may be found in a paper published by Hanjinsheng et al: transmutation performance of minor actinides in lead-cooled fast reactors [ J ] isotopes 2019,32(01):22-28 in the arrangement shown in FIG. 2.
In the invention, the number of the transmutation rods and the center-to-center distance between the transmutation rods can be adjusted according to the power level and the critical requirement of the molten salt fast reactor. The center-to-center distance refers to the distance between the centers of adjacent transmutation rods. Preferably, the number of the transmutation rods is 4-37.
In the present invention, the fuel salt may be a fuel salt conventional in the art, and generally includes nuclear fuel and carrier salts. The applicant studies and finds that the insertion of said transmutation rods containing transuranic elements into said molten salt fast reactor causes an increase in reactivity and the insertion of said transmutation rods containing a layer of fission products into said molten salt fast reactor causes a decrease in reactivity, for which purpose it is known to a person skilled in the art, after understanding the technical solution of the present invention, that the core criticality can be achieved by adjusting the concentration of fissile nuclear fuels in said molten salt fast reactor.
Wherein, the carrier salt is preferably a chloride salt or a fluoride salt, and more preferably sodium chloride or lithium beryllium fluoride.
Wherein the nuclear fuel is preferably a chloride or fluoride of transuranic and/or fertile elements; wherein the transuranic element is an isotope of neptunium: (237～238Np), isotopes of plutonium (238～242Pu), americium isotopes (b)241～244Am) and the isotopes of curium (a)242～248Cm) and the proliferation element is thorium(s) ((III)232Th) natural uranium: (2350.72% by weight of U or depleted uranium (U)235U weight percent 0.2%), more preferably thorium.
Wherein, the molar percentage of the nuclear fuel in the fuel salt is preferably 1.0-50.0%.
In the invention, preferably, at the initial stage of reactor core operation, the mass fraction of transuranic elements in the transmutation rods in the transuranic elements in the molten salt fast reactor is 50-100%.
In the invention, the operating power of the molten salt fast reactor is preferably 100-3000 MWth.
In the invention, the nuclear fuel ratio power of the molten salt fast reactor at the initial operation stage of the reactor core is preferably 350-1550 kW/kg. Wherein the nuclear fuel ratio power refers to the thermal power generated by a unit mass of nuclear fuel (such as TRU) in the nuclear reactor core, and the unit is kW/kg.
In the invention, the initial residual reactivity of the reactor core of the molten salt fast reactor is preferably 500-4000 pcm.
In the invention, when the molten salt fast reactor is operated at a certain power and nuclear fuel in the reactor core is not enough to maintain the critical state of the reactor core, the critical state of the reactor core can be maintained through online post-treatment and online refueling.
Wherein the on-line post-treatment can be a routine operation in the field, and the post-treated nuclide and post-treatment period are determined according to the actual post-treatment capability.
Wherein the on-line feeding can be conventional operation in the field, and the feeding nuclide can comprise233U、235U、237Np、239Pu、241Pu、243Cm and245cm, and controlling the residual reactivity of the molten salt fast reactor after adding materials within 100-1000 pcm.
On the basis of the common knowledge in the field, the above preferred conditions can be combined randomly to obtain the preferred embodiments of the invention.
The reagents and starting materials used in the present invention are commercially available.
The positive progress effects of the invention are as follows:
the molten salt fast reactor of the invention adopts solid fuel and liquid fuel at the same time, improves the nuclear fuel ratio power of the reactor core at the initial operation stage on the premise of not influencing the safety performance of the reactor core, improves the loading capacity of the TRU on the premise of not breaking through the solubility of the liquid fuel salt, and further improves the transmutation variable of the TRU. The liquid fuel salt of the molten salt fast reactor can maintain the critical operation of the reactor only by providing a small amount of nuclear fuel, thereby reducing the delayed neutron loss caused by the flow of the fuel salt and improving the inherent safety of the reactor core.
The molten salt fast reactor can be used for carrying out on-line post-treatment and on-line feeding, and can prolong the running time of the reactor and the transmutation time of the TRU in the reactor, thereby further improving the transmutation amount of the TRU.
Drawings
Fig. 1 is a schematic front view of a molten salt fast reactor of example 1.
Fig. 2 is a schematic top view of the molten salt fast reactor of example 1.
Fig. 3 is a schematic view of a baffle of the molten salt fast reactor of example 1.
FIG. 4 is a schematic front view of a molten salt fast reactor of comparative example 1.
Fig. 5 is a schematic top view of a molten salt fast reactor of comparative example 1.
Fig. 6 is a schematic top view of a molten salt fast reactor of comparative example 2.
Description of the reference numerals
Active region wall 1
Reflective layer 2
Stack container 3
Upper deflector 4
Lower deflector 5
Upper chamber 6
Lower chamber 7
Fuel salt outlet 8
Fuel salt inlet 9
Transmutation rod 10
Fuel salt zone 11
Groove 12
Small hole 13
Accommodation space 101
Intermediate layer 102
Envelope 103
Detailed Description
The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention. The experimental methods without specifying specific conditions in the following examples were selected according to the conventional methods and conditions, or according to the commercial instructions.
Example 1
As shown in fig. 1 to 3, embodiment 1 provides a molten salt fast reactor for solid-liquid mixed fuel, which includes an active region wall 1 and an active region located inside the active region wall 1; the active region consists of a transmutation rod 10 and a fuel salt region 11; the space enclosed by the inner wall of the active zone wall 1 and the outer wall of the transmutation rod 10 is a fuel salt zone 11; the transmutation rod 10 is internally provided with an accommodating space 101, and a fuel salt area 11 is used for accommodating fuel salt; the transmutation rods 10 are arranged in the fuel salt region 11, and the transmutation rods 10 are arranged in the middle of the active region; the ratio of the equivalent diameter of the central portion to the equivalent diameter of the active region is 0.77. The middle portion is a regular hexagonal area (shown as a dashed area in fig. 2) located at the center of the active region. At this time, the calculation method of the equivalent diameter of the middle part is to calculate the diameter of the circle with the same actual cross-sectional area of the regular hexagon. During the arrangement process of the transmutation rods, the outer walls of the transmutation rods are in the range of the regular hexagon area.
The active region has an equivalent diameter of 135 cm. The active region is cylindrical. The height of the active region was 135 cm.
The accommodating space 101 in the transmutation rod 10 is a transmutation region, and the accommodating space 101 is used for filling transuranic nitride TRUN, wherein TRU is separated from spent fuel with 60Gwd/ton discharged fuel consumption of pressurized water reactor and 5-year cooling, and the specific component of TRU is 6.3%237Np:2.7％238Pu:45.9％239Pu:21.5％240Pu:10.7％241Pu:6.7％242Pu:3.4％241Am:1.9％243Am:0.8％244Cm:0.1％245Cm, the percentage is mole percent.
The transmutation rod 10 comprises an accommodating space 101, an intermediate layer 102 and an enclosure 103 from inside to outside, wherein the accommodating space 101, the intermediate layer 102 and the enclosure 103 are coaxially arranged; the intermediate layer 102 is a neutron poison layer. The transmutation rods 10 are circular in cross-section. The cross-section of the receiving space 101, the intermediate layer 102 and the envelope 103 is circular. The transmutation rods 10 are arranged in a triangular grid within the fuel salt zone 11. The center-to-center distance between the transmutation rods 10 is 51.8cm, and the number of the transmutation rods 10 is 19.
Wherein the equivalent radius of the receiving space 101 is 3.9 cm. The neutron poison in the neutron poison layer is Gd2O3. The thickness of the intermediate layer 102 was 11 cm. The material of the cladding 103 is a nickel-based alloy. The thickness of the envelope 103 is 1 cm. A heat insulating layer (not shown in the figure) is arranged between the intermediate layer 102 and the cladding 103, the material of the heat insulating layer is helium, and the thickness of the heat insulating layer is 1 mm.
The material of the active zone wall 1 is a nickel-based alloy. The active zone wall 1 includes an upper wall, a side wall, and a lower wall. The thickness of the upper wall is 2 cm; the thickness of the side wall is 2 cm; the thickness of the lower wall was 2 cm. Wherein, the upper wall is conical with radian; the lower wall is conical with a curvature. The center of the upper wall is provided with a fuel salt outlet 8; the center of the lower wall is provided with a fuel salt inlet. The fuel salt inlet is cylindrical; the fuel salt outlet 8 is cylindrical.
The active region wall 1 further comprises an upper chamber 6 therein, the upper chamber 6 is located between the active region and the upper wall, and the bottom of the upper chamber 6 is communicated with the active region. The height of the upper chamber 6 is 10 cm. The active zone wall 1 also includes a lower chamber 7 therein, the lower chamber 7 being located between the active zone and the lower wall, the top of the lower chamber 7 being in communication with the active zone. The height of the lower chamber 7 is 10 cm.
An upper guide plate 4 is arranged between the active area and the upper chamber 6, and a lower guide plate 5 is also arranged between the active area and the lower chamber 7. The two flow guide plates are provided with grooves 12 and small holes 13, the shapes and the sizes of the grooves 12 are the same as the cross sections of the transmutation rods 10, the number of the grooves 12 is the same as the number of the transmutation rods 10 and used for fixing the transmutation rods 10 in the fuel salt region 11, and the small holes 13 are used for communicating the active region with the upper chamber 6 and the active region with the lower chamber 7, so that the circulation of the fuel salt is realized. The two guide plates are 2cm thick. The two guide plates are made of nickel-based alloy.
The periphery of the active zone wall 1 is provided with a reflective layer 2 and a stack container 3. The material of the reflecting layer 2 is beryllium oxide. The thickness of the reflective layer 2 was 40 cm. The material of the stack container 3 is nickel-based alloy. The thickness of the stack container 3 is 5 cm.
The liquid fuel salt contains 55% NaCl-1% TRUCl3-44％ThCl3The percentage is mole percent, and the abundance of Cl-37 is 24.23%.
At the initial running stage of the reactor core, the mass fraction of transuranic elements in the transmutation rods 10 in the transuranic elements in the molten salt fast reactor is 83.80%. The nuclear fuel ratio power of the molten salt fast reactor at the initial operation stage of the reactor core is 642.89 kW/kg. The reactor core reactivity temperature coefficient of the molten salt fast reactor is-0.08 pcm/K, the effective delayed neutron share in the reactor core is 235.2pcm, and the effective delayed neutron share of the liquid fuel salt is only 9.39 pcm.
The initial residual reactivity of the molten salt fast reactor is 2364pcm, and when the residual reactivity is 0 or even negative, the online post-treatment and online feeding are carried out. The nuclide and post-treatment period of the on-line post-treatment are as follows: the cycle for removing the difficultly soluble fission products (Xe, Kr, etc.) is 30s, the cycle for removing the easily soluble fission products (Sm, Eu, Gd, etc.) is 1000 days, and the cycle for extracting the actinides (Pa, Np, etc.) is 1000 days. The adding nuclide of the on-line adding is mixed fuel salt of TRU and thorium, and the residual reactivity of the reactor core after adding is between 100pcm and 1000 pcm.
The molten salt fast reactor is operated at 2500MWth, and the annual TRU transmutation amount of 10 years, 20 years and 30 years of operation is 334.33kg/GWth/year, 296.61kg/GWth/year and 268.79kg/GWth/year respectively.
Example 2
The solid-liquid mixed fuel molten salt fast reactor of the embodiment 2 is different from the embodiment 1 only in the parameters related to the transmutation rods 10.
The parameters related to the transmutation rods 10 differ from those of example 1 as follows:
the transmutation rods 10 are arranged in the fuel salt region 11, and the transmutation rods 10 are arranged in the middle of the active region; the ratio of the equivalent diameter of the central portion to the equivalent diameter of the active region is 0.80. The equivalent radius of the accommodation space 101 is 4.1 cm. The intermediate layer 102 is a fission product layer, the material of the fission product is Tc-99, and the thickness of the fission product layer is 12 cm. The transmutation rods 10 are arranged in a triangular grid within the fuel salt zone 11. The center-to-center distance between the transmutation rods 10 is 54.2cm, and the number of the transmutation rods 10 is 19.
At the initial running stage of a reactor core, the mass fraction of transuranic elements in the transmutation rods 10 in the transuranic elements in the molten salt fast reactor is 85.67%, the nuclear fuel ratio power of the molten salt fast reactor is 594.22kW/kg, the reactor core reactivity temperature coefficient of the molten salt fast reactor is-0.1 pcm/K, the effective delayed neutron fraction in the reactor core is 238.1pcm, and the effective delayed neutron fraction of liquid fuel salt is only 3.21 pcm.
The initial residual reactivity of the molten salt fast reactor is 3217pcm, and when the residual reactivity is 0 or even negative, on-line post-treatment and on-line feeding are carried out. The operation of the in-line post-treatment and in-line addition was the same as in example 1.
The molten salt fast reactor is operated at 2500MWth, and the annual TRU transmutation amount of 10 years, 20 years and 30 years of operation is 341.21kg/GWth/year, 323.71kg/GWth/year and 305.02kg/GWth/year respectively.
Comparative example 1
As shown in FIGS. 4-5, the liquid fuel molten salt fast reactor of comparative example 1 is different from that of example 1 only in that the active zone of comparative example 1 only contains liquid fuel salt, and no transmutation rods are arranged.
In the initial operation stage of the reactor core, the nuclear fuel ratio power of the molten salt fast reactor is 304.99kW/kg, the reactor core reactivity temperature coefficient of the molten salt fast reactor in the initial operation stage is-1.79 pcm/K, and the effective delayed neutron share of the fuel salt is 325.8 pcm.
The initial residual reactivity of the molten salt fast reactor is 3076pcm, and when the core fuel in the reactor core is not enough to maintain the critical value of the reactor core (the residual reactivity is 0 or even negative), the online post-treatment and online refueling are carried out. The operation of the in-line post-treatment and in-line addition was the same as in example 1.
The molten salt fast reactor is operated at 2500MWth, and the annual TRU transmutation amount of 10 years, 20 years and 30 years of operation is 235.11kg/GWth/year, 198.86kg/GWth/year and 183.13kg/GWth/year respectively.
Comparative example 2
As shown in fig. 6, the difference between the solid-liquid mixed fuel molten salt fast reactor of the comparative example 2 and the example 1 lies only in the geometrical structure and arrangement of the transmutation rods 10, specifically:
the equivalent radius of the accommodation space 101 is 3.94 cm. The intermediate layer 102 is a neutron poison layer, which is Gd2O3The thickness of the neutron poison layer is 10 cm. The active zone consists of a transmutation rod 10 and a fuel salt zone 11.
In comparative example 2, the central portion of the active region is a regular hexagonal area (shown as a dotted area in fig. 6) located at the center of the active region. At this time, the calculation method of the equivalent diameter of the middle part is to calculate the diameter of the circle with the same actual cross-sectional area of the regular hexagon. The ratio of the equivalent diameter of the middle portion to the equivalent diameter of the active region is 0.83. The transmutation rods 10 are arranged along the hexagonal region outside the hexagonal region.
The center-to-center distance between the transmutation rods 10 is 31.88cm, and the number of the transmutation rods 10 is 18.
At the initial running stage of a reactor core, the mass fraction of transuranic elements in the transmutation rods 10 in the transuranic elements in the molten salt fast reactor is 87.89%, the nuclear fuel ratio power of the molten salt fast reactor is 689.84kW/kg, the reactor core reactivity temperature coefficient of the molten salt fast reactor is-0.13 pcm/K, the effective delayed neutron fraction in the reactor core is 370.6pcm, and the effective delayed neutron fraction of liquid fuel salt is only 8.08 pcm.
The initial residual reactivity of the molten salt fast reactor is 3069pcm, and when the residual reactivity is 0 or even negative, the online post-treatment and online feeding are carried out. The operation of the in-line post-treatment and in-line addition was the same as in example 1.
The molten salt fast reactor is operated at 2500MWth, and the annual TRU transmutation amount of 10 years, 20 years and 30 years of operation is 232.13kg/GWth/year, 162.26kg/GWth/year and 126.98kg/GWth/year respectively.
The results of the runs of the examples and comparative examples are shown in table 1 below.
TABLE 1 comparison of operating results of examples 1-2 and comparative examples 1-2
Figure BDA0003322293130000121
In comparative example 2, in addition to the transmutation amount being lower than that of example 1, the reactor of comparative example 2 is liable to be operated with a local overheating phenomenon. Therefore, the safety of the core of example 1 was higher than that of comparative example 2.

Claims (10)

1. A molten salt fast reactor, characterized in that it comprises an active zone wall and an active zone located inside the active zone wall;
the active region comprises a transmutation rod and a fuel salt region, wherein a containing space is arranged in the transmutation rod, and the fuel salt region is used for containing fuel salt;
the transmutation rods are arranged in the fuel salt region, and the transmutation rods are arranged in the middle of the active region;
the ratio of the equivalent diameter of the middle part to the equivalent diameter of the active area is 0.6-0.9.
2. The molten salt fast reactor of claim 1, wherein the molten salt fast reactor meets one or more of the following conditions:
(1) the material of the active zone wall is one or more of nickel-based alloy, molybdenum-rhenium alloy and niobium-zirconium alloy, and preferably the nickel-based alloy;
(2) the active zone wall comprises an upper wall, a side wall and a lower wall;
(3) the equivalent diameter of the active area is 80-300 cm;
(4) the active region is cylindrical;
(5) the ratio of the height of the active region to the equivalent diameter of the active region is 0.5-2.5.
3. The molten salt fast reactor of claim 2, characterized in that the molten salt fast reactor meets one or more of the following conditions:
(1) the thickness of the upper wall is 1-3 cm;
(2) the thickness of the side wall is 1-5 cm;
(3) the thickness of the lower wall is 1-3 cm;
(4) the upper wall is conical with radian;
(5) the lower wall is conical with a radian;
(6) a fuel salt outlet is formed in the center of the upper wall; the center of the lower wall is provided with a fuel salt inlet; the fuel salt inlet is preferably cylindrical; the fuel salt outlet is preferably cylindrical;
(7) the active area wall also comprises an upper chamber, the upper chamber is positioned between the active area and the upper wall, and the bottom of the upper chamber is communicated with the active area; the height of the upper cavity is preferably 1-20 cm;
(8) the active region wall also comprises a lower chamber, the lower chamber is positioned between the active region and the lower wall, and the top of the lower chamber is communicated with the active region; the height of the lower chamber is preferably 1-20 cm.
4. The molten salt fast reactor according to claim 3, characterized in that a flow deflector is further provided between the active zone and the upper chamber, and/or between the active zone and the lower chamber;
the guide plate is preferably provided with a groove and a small hole;
the thickness of the flow guide plate is preferably 1-5 cm;
the material of the flow guide plate is preferably one or more of nickel-based alloy, molybdenum-rhenium alloy and niobium-zirconium alloy, and more preferably nickel-based alloy.
5. The molten salt fast reactor of claim 1, characterized in that the periphery of the active zone wall is provided with a reflecting layer and a reactor vessel;
preferably, the material of the reflecting layer is graphite, beryllium or beryllium oxide, and more preferably beryllium oxide;
preferably, the thickness of the reflecting layer is 15-60 cm;
preferably, the material of the stack container is one or more of nickel-based alloy, molybdenum-rhenium alloy and niobium-zirconium alloy, and more preferably nickel-based alloy;
preferably, the thickness of the stack container is 2-10 cm.
6. The molten salt fast reactor of claim 1, wherein the molten salt fast reactor meets one or more of the following conditions:
(1) the active region consists of a transmutation rod and a fuel salt region;
(2) the accommodating space in the transmutation rod is filled with transuranic element oxide, transuranic element nitride or transuranic element carbide;
preferably, the transuranic oxide in the accommodating space is TRUO2(ii) a The transuranic nitride in the accommodating space is TRUN; the transuranic carbide in the accommodating space is TRU3C2、TRUCxX is 0.6 to 0.92, TRU2C3Or TRUC2(ii) a TRU is one or more of an isotope of neptunium, an isotope of plutonium, an isotope of americium, and an isotope of curium;
(3) the equivalent radius of the accommodating space is 1-10 cm;
(4) the transmutation rod comprises the accommodating space, an intermediate layer and an enclosure from inside to outside, and the accommodating space, the intermediate layer and the enclosure are coaxially arranged; the intermediate layer is a neutron poison layer or a fission product layer.
7. The molten salt fast reactor of claim 6, characterized in that it satisfies one or more of the following conditions:
(1) the neutron poison in the neutron poison layer is boron and compounds thereof, europium and compounds thereof, gadolinium and compounds thereof or samarium and compounds thereof, preferably Gd2O3；
(2) Fission products in the fission product layer are one or more of Se, Sr, Zr, Nb, Tc, Pd, Sn, I, Cs and Sm;
(3) the material of the intermediate layer is not a proliferation material;
(4) the thickness of the middle layer is 2-20 cm;
(5) the material of the cladding is one or more of silicon carbide, carbon-carbon composite material, nickel-based alloy, molybdenum-rhenium alloy and niobium-zirconium alloy;
(6) the thickness of the cladding is 1-10 cm;
(7) and a heat insulation layer is arranged between the middle layer and the cladding, and the thickness of the heat insulation layer is preferably 1-5 mm.
8. The molten salt fast reactor of claim 1, wherein the molten salt fast reactor meets one or more of the following conditions:
(1) the cross section of the transmutation rod is circular, hexagonal or quadrilateral;
(2) the transmutation rods are arranged in the fuel salt region according to a triangular grid, a quadrilateral grid or along the circumference;
(3) the number of the transmutation rods is 4-37.
9. The molten salt fast reactor of claim 1, wherein the molten salt fast reactor meets one or more of the following conditions:
(1) the carrier salt in the fuel salt is chlorine salt or fluorine salt, preferably sodium chloride or fluorine lithium beryllium;
(2) the nuclear fuel in the fuel salt is chloride or fluoride of transuranic element and/or propagation element; the transuranic element is one or more of isotope of neptunium, isotope of americium and isotope of curium; the proliferation element is one or more of thorium, natural uranium or depleted uranium;
(3) in the fuel salt, the molar percentage of nuclear fuel in the fuel salt is 1.0-50.0%.
10. The molten salt fast reactor of claim 1, wherein the molten salt fast reactor meets one or more of the following conditions:
(1) at the initial running stage of a reactor core, the mass share of transuranic elements in the transmutation rods in the transuranic elements in the molten salt fast reactor is 50% -100%;
(2) the operating power of the molten salt fast reactor is 100-3000 MWth;
(3) the nuclear fuel ratio power of the molten salt fast reactor at the initial running stage of the reactor core is 350-1550 kW/kg;
(4) the initial residual reactivity of the reactor core of the molten salt fast reactor is 500-4000 pcm.
CN202111249954.2A 2021-10-26 2021-10-26 Molten salt fast reactor Pending CN114093529A (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US12012827B1 (en) 2023-09-11 2024-06-18 Natura Resources LLC Nuclear reactor integrated oil and gas production systems and methods of operation

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US12018779B2 (en) 2022-09-20 2024-06-25 Abilene Christian University Stabilizing face ring joint flange and assembly thereof
US12012827B1 (en) 2023-09-11 2024-06-18 Natura Resources LLC Nuclear reactor integrated oil and gas production systems and methods of operation

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