CN110349684B - Reactivity control device - Google Patents
Reactivity control device Download PDFInfo
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- CN110349684B CN110349684B CN201910635563.0A CN201910635563A CN110349684B CN 110349684 B CN110349684 B CN 110349684B CN 201910635563 A CN201910635563 A CN 201910635563A CN 110349684 B CN110349684 B CN 110349684B
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- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C7/00—Control of nuclear reaction
- G21C7/06—Control of nuclear reaction by application of neutron-absorbing material, i.e. material with absorption cross-section very much in excess of reflection cross-section
- G21C7/08—Control of nuclear reaction by application of neutron-absorbing material, i.e. material with absorption cross-section very much in excess of reflection cross-section by displacement of solid control elements, e.g. control rods
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- G—PHYSICS
- G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
- G21C—NUCLEAR REACTORS
- G21C7/00—Control of nuclear reaction
- G21C7/06—Control of nuclear reaction by application of neutron-absorbing material, i.e. material with absorption cross-section very much in excess of reflection cross-section
- G21C7/08—Control of nuclear reaction by application of neutron-absorbing material, i.e. material with absorption cross-section very much in excess of reflection cross-section by displacement of solid control elements, e.g. control rods
- G21C7/12—Means for moving control elements to desired position
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- 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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Abstract
The invention provides a reactivity control device, which comprises a graphite movable block, a graphite fixed block, a connecting part, an electromagnetic device and a driving part, wherein the graphite movable block can move relative to the graphite fixed block, the connecting part can drive the graphite movable block to move in a direction close to or far away from the bottom of a reactor core, and the driving part and the connecting part can be connected through the electromagnetic device, so that when the reactor normally operates, the driving part drives the connecting part to drive the graphite movable block to move to the bottom of the reactor core; when an emergency working condition occurs, the graphite movable block rapidly falls off from the bottom of the reactor core under the action of self weight. The reactivity control device controls the reactivity by utilizing different position states of the graphite movable block and the graphite fixed block, and is favorable for further improving the emergency shutdown speed of the reactor according to the neutron leakage principle; the reactivity control device has the advantages of simple structure, high safety control coefficient, strong reliability, high control precision and the like.
Description
Technical Field
The invention relates to the field of nuclear reactor control, in particular to a reactivity control device.
Background
The zero power reactor is a device for a controlled chain type nuclear reaction operating at a low power level, which is one of important experimental devices for conducting physical studies of reactors. The zero-power reactor has the characteristics of low operating power, simple structure, flexible and easy active area and the like, and is used for carrying out the following work: physical simulation of a particular reactor is performed to improve the reactor design; systematically investigating various grid characteristics; measuring the absorption cross section of the material, and checking the stacking material; researching the condition that the material containing fissile materials reaches a critical state, and providing technical data for the nuclear fuel industry; training physical experimenters and heap operators and the like.
An accelerator driven subcritical reactor system (ADS) is a new nuclear energy system formed by coupling and integrating a high-energy proton accelerator with a spallation neutron target and a subcritical reactor. For example, the reactor core structure of the ADS lead coolant critical reactor is used for realizing the bombardment of heavy metal spallation targets by proton beams to cause spallation reaction and providing exogenous neutrons for the subcritical reactor to drive nuclear reaction in the reactor, thereby realizing the functions of nuclear waste transmutation and the like.
The reactivity control device is a core part related to the safety of the reactor operation, and most of the common control devices for controlling the reactivity have a rod-shaped or rod-bundle-shaped structure and are arranged in the upper area of the reactor core. In the processes of starting, power conversion and shutdown of the reactor, the reactivity of the reactor is controlled by controlling the lifting, inserting and keeping movement of the control rods, so that the reactor is ensured to work in a controlled state all the time. Particularly, under the condition of emergency working conditions, the control rod system generally utilizes gravity to freely fall to the reactor core so as to stop the reactor and ensure the safety of the reactor. The control rod control reactivity is based on neutron absorption.
However, in order to ensure the operation safety of the reactor, further increase the safety margin, and ensure that the reactor can be brought into emergency shutdown in case of emergency, the shutdown achieved only by the control rod system has the disadvantages of low safety factor, slow emergency shutdown speed, etc., and thus, it is necessary to add an additional reactivity control device to assist in the safe shutdown.
Disclosure of Invention
In order to solve at least one of the above technical problems, an embodiment of the present invention provides a reactivity control apparatus, which can implement a fast and safe reactor shutdown in an emergency condition of a reactor based on a reactor provided with a control rod system, thereby increasing an operation safety factor of the reactor.
An embodiment of the present invention provides a reactivity control apparatus including: a graphite movable block configured to move to the bottom of the reactor core when the reactor is in operation; when the reactor is shut down, it exits the bottom of the reactor core; a graphite fixed block surrounding the graphite movable block, the graphite movable block being disposed to be movable relative to the graphite fixed block; the connecting part is arranged to drive the graphite movable block to move in a direction close to or far away from the bottom of the reactor core; an electromagnetic device comprising a first portion and a second portion, the first portion and the second portion having an attractive force therebetween when the electromagnetic device is energized; a drive portion at which the first portion of the electromagnetic device is disposed, the drive portion being configured to drive the first portion in motion; when the driving part drives the first part to move, the first part drives the second part to move, and the second part drives the connecting part to move, so that the connecting part drives the graphite movable block to move; when the reactor is powered off accidentally or needs emergency shutdown, the electromagnetic device is powered off, and the graphite movable block moves in the direction far away from the bottom of the reactor core.
According to an embodiment of the invention, the reactivity control device further comprises a receptacle arranged to fall into the receptacle when the movable graphite block is moved in a direction away from the bottom of the reactor core.
According to an embodiment of the present invention, a container includes a buffer block and a spring, one end of the spring is connected to the buffer block, and the other end is connected to the bottom of the container; the buffer block and the spring are arranged to compress the buffer block and the spring when the graphite movable block falls into the container to contact the buffer block.
According to an embodiment of the invention, the drive section comprises a drive assembly and a motor, the motor being arranged such that, when the reactor is in operation, the motor rotates in a forward direction to drive the drive assembly towards a direction close to the bottom of the reactor core; when the reactor is shut down, the motor rotates in the reverse direction to drive the driving assembly to move in a direction away from the bottom of the reactor core.
According to an embodiment of the present invention, a driving assembly includes a first plate portion, a second plate portion, a seat body, a guide post, and a lead screw, wherein the seat body is disposed between the first plate portion and the second plate portion; the top end and the bottom end of the guide column are fixedly connected with the first plate part and the second plate part respectively, and the guide column penetrates through the seat body; the lead screw drives the base body to move between the first plate part and the second plate part along the guide column; the first part of the electromagnetic device is arranged on the base body.
According to an embodiment of the present invention, the reactivity control apparatus further includes a support assembly, the support assembly includes a top plate, a bottom plate, and a support column, the top plate is fixedly connected to the second plate portion; the bottom plate is fixedly connected with the ground; the support column is supported between the top plate and the bottom plate. According to an embodiment of the present invention, the connecting portion slidably penetrates the first plate portion and the seat body; the second part of the electromagnetic device is arranged at the bottom of the connecting part.
According to the embodiment of the invention, the connection part of the graphite movable block and the connecting part is arranged in a centering way relative to the screw rod.
According to the embodiment of the invention, when the graphite movable block moves to the bottom of the reactor core, the graphite movable block and the graphite fixed block together serve as a bottom reflecting layer of the reactor core; when the graphite movable block leaves the bottom of the reactor core, a cavity structure is formed in the middle of the graphite fixed block.
Embodiments of the present invention also provide a zero power reactor including the reactivity control apparatus described above.
Compared with the prior art, the invention has at least one of the following beneficial effects:
(1) the reactivity control device controls the reactivity of the reactor core by utilizing different positions of the graphite movable block and the graphite fixed block, and is favorable for further improving the emergency shutdown speed of the reactor; the reactivity control device has the advantages of simple structure, high safety control coefficient, strong reliability, high control precision and the like;
(2) the reactivity control device can be used for controlling a zero-power reactor, is beneficial to developing a plurality of zero-power physical experiments, and thus provides experimental data or accumulated experience for researching reactor characteristics such as shutdown dynamic characteristics under different subcritical degrees, dynamic behavior characteristics introduced by positive and negative reactivity and the like.
Drawings
Other objects and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings, and may assist in a comprehensive understanding of the invention.
FIG. 1 is a schematic perspective sectional view of the overall structure of a reactivity control apparatus according to an embodiment of the present invention;
FIG. 2 is a front view of the overall structure of the reactivity control apparatus according to the embodiment of the present invention;
fig. 3 is a schematic structural diagram of an electromagnetic device of the reactivity control device according to the embodiment of the present invention.
It is noted that the drawings are not necessarily to scale and are merely illustrative in nature and not intended to obscure the reader.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings of the embodiments of the present invention. It should be apparent that the described embodiment is one embodiment of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention without any inventive step, are within the scope of protection of the invention.
Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs.
The reactivity control device is a core part related to the operation safety of a reactor, and a common measure for the safety control of the nuclear reactor is to arrange a control rod driving mechanism in an upper area of the reactor core. The control rod driving mechanism is a servo mechanism of a reactor control system and a safety protection system, and realizes the startup of a reactor, the regulation of the power of the reactor, the maintenance of the power, the stopping of the reactor and the rapid shutdown under accident conditions by lifting, descending, keeping or rapidly inserting control rods at different positions of a reactor core, thereby directly influencing the normal safe operation of the reactor or avoiding the occurrence of accidents. In general, when a reactor normally operates, a certain moving speed of a control rod is required; when an emergency accident condition occurs, the control rod assembly is required to be automatically disconnected, so that the control rod is quickly inserted into the reactor core by the dead weight to complete shutdown; the shutdown time from the acquisition of the signal to the safe insertion of the control rods into the core does not exceed 2 s. The neutron absorption principle is adopted for realizing shutdown based on the insertion of control rods into a reactor core.
However, the control rod driving mechanism has the disadvantages of low safety factor, slow scram speed, incapability of accurately controlling the scram and the like, and for some liquid heavy metal cooled reactors such as lead-cooled reactors, the density of the safety rod is much lower than that of the coolant due to the fact that the density of the eutectic mixture of the lead-bismuth alloy used as the coolant is high and the density of the main absorber material of the safety rod such as boron carbide in the control rod system is low, thereby being unfavorable for the safety insertion into the reactor core (influenced by buoyancy) when the safety rod falls. Thereby also increasing the difficulty of control rod structural design.
In order to improve the flexibility and reliability of safety control of the reactor, the embodiment of the invention provides the reactivity control device, and when an emergency accident condition occurs, the reactivity control device can further improve the emergency shutdown speed of the reactor, so that the safety is ensured.
As shown in fig. 1 to 3, the reactivity control apparatus 100 includes: a graphite movable block 1, the graphite movable block 1 being configured to move to the bottom of a reactor core when the reactor is in operation; when the reactor is shut down, it exits the bottom of the reactor core; the graphite fixed block 2 surrounds the graphite movable block 1, and the graphite movable block 1 is arranged to move relative to the graphite fixed block 2; the connecting part 3 is arranged to drive the graphite movable block 1 to move in a direction close to or far away from the bottom of the reactor core; an electromagnetic device 5, said electromagnetic device 5 comprising a first portion 51 and a second portion 52, said first portion 51 and said second portion 52 having an attractive force when said electromagnetic device 5 is energized; a driving part 6, wherein the first part 51 of the electromagnetic device 5 is arranged on the driving part 6, and the driving part 6 is arranged to drive the first part 51 to move; the second portion 52 of the electromagnetic device 5 is disposed on the connecting portion 3, an electromagnetic force acts between the first portion 51 and the second portion 52, when the driving portion 6 drives the first portion 51 to move, the first portion 51 drives the second portion 52 to move, the second portion 52 drives the connecting portion 3 to move, and thus the connecting portion 3 drives the graphite movable block 1 to move; when the reactor is powered off accidentally or needs emergency shutdown, the electromagnetic device 5 is powered off, and the graphite movable block 1 moves in the direction far away from the bottom of the reactor core.
As shown in fig. 1 or 2, the graphite fixed block 2 surrounds the graphite movable block 1, and the graphite movable block 1 is movable relative to the graphite fixed block 2. The movable graphite block 1 and the fixed graphite block 2 may be graphite blocks having a certain density and shape, for example, the movable graphite block 1 may have a diameter D1The corresponding graphite fixing block 2 may be a ring structure having a hollow cylinder, for example, the graphite fixing block 2 has an inner diameter D2Outer diameter of D3Wherein D is1Greater than D2So that the graphite movable block 1 can be positioned in the hollow structure of the graphite fixed block 2. In particular, e.g. D1Is 240mm, D2Is 246mm, D3Is 517 mm. The graphite movable block 1 and the graphite fixed block 2 have the following positional relationship: when the reactor is started, the graphite movable block 1 moves to the bottom of the reactor core of the reactor, and the graphite movable block 1 is surrounded by the graphite fixed block 2 and is positioned at the same horizontal position; when the reactor needs to be stopped, the graphite movable block 1 leaves the bottom of the reactor core of the reactor, and the position of the graphite fixed block 2 is not changed.
As shown in fig. 1 or 2, the graphite movable block 1 may be fixedly mounted on the top of the connecting portion 3 by screws, so that the connecting portion 3 can drive the graphite movable block 1 to move in a direction close to or away from the bottom of the reactor core. The graphite fixing block 2 can be fixedly arranged on an operation platform 9 through screws. The connecting part 3 may have a rod-shaped structure, such as a slide column, and can bear the graphite movable block 1 and move the graphite movable block 1 up and down.
As shown in fig. 2 or 3, first portion 51 and second portion 52 of electromagnetic device 5 may be a composition having generally electromagnetic properties. For example, the first portion 51 may be a solenoid armature, and the second portion 52 may be configured as a core having a solenoid structure, wherein when the solenoid device 5 is energized, the solenoid armature attracts the core, thereby causing an electromagnetic force between the first portion 51 and the second portion 52 to attract each other. The first part 51 may be provided as an iron core having a certain electromagnetic coil structure, and the second part 52 may be provided as an electromagnet armature. Alternatively, the first portion 51 and the second portion 52 may be a combination of electromagnetic structures of other types.
As shown in fig. 1 or 2, the reactivity control apparatus 100 further includes a container 4, and the container 4 is configured to fall into the container 4 when the movable graphite block 1 moves in a direction away from the bottom of the reactor core. Wherein, the container 4 comprises a buffer block 41 and a spring 42, one end of the spring 42 is connected to the buffer block 41, and the other end is connected to the bottom of the container 4; the buffer block 41 and the spring 42 are arranged to compress the buffer block 41 and the spring 42 when the graphite movable block 1 falls into the container 4 to contact the buffer block 41.
As shown in fig. 1 or 2, the container 4 is arranged at the downstream of the graphite fixed block 2, and the top of the container 4 is fixedly connected with the bottom of the graphite fixed block 2. The top of the container 4 is opened, so that the graphite movable block 1 can fall into the container 4 through the opening. The buffer block 41 and the bottom of the container 4 are each provided with a through-hole structure in the middle so that the connection part 3 can pass through the through-hole. The container 4 may, for example, have a cylindrical barrel-like structure with an internal diameter D4Outer diameter of D5(ii) a The top of the container 4 is opened, and the bottom is provided with a through hole at the middle position; in order to make the graphite movable block 1 smoothly fall into the container 4 and ensure the stable falling process of the graphite movable block 1 by the inner space of the container 4, the size of the container 4 can be correspondingly designed according to the sizes of the graphite movable block 1 and the graphite fixed block 2, for example, D4Is 245mm, D5Is 258 mm. Accordingly, the buffer block 41 may be a thin circular plate provided with a through hole at an intermediate position, and having a diameterD6Greater than D1To be able to fully contact the surface of the graphite movable block 1, e.g. D6May be 244 mm. The springs 42 are arranged between the buffer block 41 and the bottom of the container 4 and around the circumference of the through hole, the number of which may be as desired, for example 4.
Further, the material of the container 4 may be stainless steel, which is used to accommodate the graphite movable block 1. The buffer block 41 and the spring 42 are used for protecting the graphite movable block 1 when the graphite movable block 1 moves into the container 4; particularly, when an emergency condition occurs, since the graphite movable block 1 falls down rapidly by its own weight, a large impact force is easily generated, and the buffer block 41 and the spring 42 can provide a proper buffer effect, thereby protecting the structure of the graphite movable block 1 from being damaged and prolonging the service life thereof. The buffer block 41 may be made of polyethylene, rubber, resin, or the like, preferably polyethylene; the structural design of the graphite movable block needs to meet the requirement of having certain bearing capacity on the graphite movable block 1. When the polyethylene buffer block is adopted, on one hand, the polyethylene material is a hydrogen-containing compound which does not absorb neutrons; on the other hand, polyethylene has the advantages of economy, easy processing and forming, good toughness, durability and the like.
As shown in fig. 1 or 2, the driving part 6 comprises a driving assembly and a motor 61, wherein the motor 61 is arranged such that when the reactor is operated, the motor 61 rotates in a forward direction to drive the driving assembly to move towards a direction close to the bottom of the reactor core; when the reactor is shut down, the motor 61 is rotated in reverse to drive the drive assembly in a direction away from the bottom of the reactor core.
As shown in fig. 1 to 3, the driving assembly includes a first plate portion 62, a second plate portion 63, a seat 64, a guide post 65 and a lead screw 66, wherein the seat 64 is disposed between the first plate portion 62 and the second plate portion 63; the guide post 65 is arranged such that the top end and the bottom end thereof are fixedly connected with the first plate part 62 and the second plate part 63, respectively, and the guide post 65 penetrates the seat body 64; the screw 66 drives the seat 64 to move along the guide post 65 between the first plate part 62 and the second plate part 63; the first portion 51 of the electromagnetic device 5 is disposed on the seat 64.
As shown in fig. 1 or 2, the first plate portion 62 and the second plate portion 63 may be rectangular plates, the seat body 64 may be a cylindrical plate, and a through hole is formed in the seat body 64, so that the guide post 65 and the lead screw 66 can pass through the through hole to be connected with the seat body 64, and the top end and the bottom end of the guide post 65 are fixedly connected with the first plate portion 62 and the second plate portion 63, respectively. Wherein, the screw 66 is arranged centrally relative to the base 64, and the guide posts 65 can be arranged oppositely relative to two ends of the screw 66. Support columns 67 can be further arranged between the first plate part 62 and the second plate part 63, and the top ends and the bottom ends of the support columns are respectively and fixedly connected with the first plate part 62 and the second plate part 63. The lead screw 66 can pass through the second plate portion 63 and be fixedly connected with the motor 61, so that the motor 61 drives the lead screw 66 and enables the seat body 64 to move along the guide column 65 between the first plate portion 62 and the second plate portion 63.
As shown in fig. 2, the driving unit 6 may further include a speed reducer 68 and a coupling 69, and the motor 61 is connected to the speed reducer 68, the coupling 69, and the screw 66 in this order from the bottom up. The coupler 69 is used for enhancing the connection and operation stability between the driving components and reducing the influence caused by adverse factors such as motion deviation, vibration and impact; simultaneously, the rotation speed of the motor 61 is precisely controlled by the decelerator 68, so that the graphite movable block 1 can be raised or lowered at a constant speed to control the reactivity.
As shown in fig. 1 or 2, the reactivity control apparatus 100 further includes a support assembly 7 including a top plate 71, a bottom plate 72, and a support column 73, the top plate 71 being fixedly connected to the second plate portion 63; the bottom plate 72 is fixedly connected with the ground; the support column 73 is supported between the top plate 71 and the bottom plate 72. The top plate 71 and the bottom plate 72 may be rectangular plates, and the support columns 73 may be provided at four angular positions with respect to the top plate 71 and the bottom plate 72, for example, 4 support columns 73 may be provided. The top plate 71 is fixedly connected to the second plate portion 63, the motor 61 is disposed below the top plate 71, and the screw 66 can be connected to the motor 61 through the second plate portion 63 and the top plate 71.
As shown in fig. 1 or 2, the connecting portion 3 slidably passes through the first plate portion 62 and the seat body 64; the second portion 52 of the electromagnetic device 5 is arranged at the bottom of the connecting portion 3. Through holes are formed in the first plate portion 62 and the seat body 64, so that the connecting portion 3 can continue to pass through the first plate portion 62 and the seat body 64 after passing through the bottom of the container 4, and the bottom of the connecting portion 3 continues to extend relative to the bottom of the seat body 64.
As shown in fig. 2, the joint of the graphite movable block 1 and the connecting portion 3 is centered with respect to the screw 66. The connecting part 3 is fixedly connected with the center of the graphite movable block 1 at the top end thereof, and then the connecting part 3 sequentially passes through the through holes at the central positions of the container 4, the first plate part 62 and the seat body 64. Simultaneously, lead screw 66 sets up centrally for pedestal 64, and the central line of the hookup location department of graphite movable block 1 and connecting portion 3 aligns for the central line of lead screw 66 position from this, and graphite movable block 1, connecting portion 3 and lead screw 66 are for the central design of integrated device, are favorable to the whole atress equilibrium of reactivity control device 100, improve its operating stability.
As shown in fig. 1 or 2, when the graphite movable block 1 moves to the bottom of the reactor core, it and the graphite fixed block 2 together act as the bottom reflecting layer of the reactor core; when the graphite movable block 1 leaves the bottom of the reactor core, the middle position of the graphite fixed block 2 forms a cavity structure. Specifically, when the reactor is started, the graphite movable block 1 moves to the bottom of the reactor core, and the graphite movable block 1 is surrounded by the graphite fixed block 2, is positioned at the same horizontal position, is jointly used as a bottom reflecting layer of the reactor core, and plays a role of reflecting neutrons together with other reflecting layer structures of the reactor core; and when the reactor needs to be stopped, the graphite movable block 1 leaves the bottom of the reactor core of the reactor, and the graphite fixed block 2 recovers the hollow structure of the graphite movable block, so that the middle position of the graphite fixed block 2 forms a cavity structure, and because the structural integrity of the reactor core bottom reflecting layer is damaged, neutrons in the reactor leak in a large amount at the cavity position to assist the reaction to stop. The high-density and high-purity graphite material is used as the reflecting layer, namely the graphite movable block 1 and the graphite fixed block 2 are used as the bottom reflecting layer together, so that the leakage probability of neutrons in the reactor is reduced, and simultaneously, compared with metal beryllium, the graphite has the advantages of low economic cost, no toxicity, strong practicability and the like.
In the embodiment of the invention, the reactivity control device is arranged below the active reaction zone of the reactor core, the structural design is simple, the control mode is flexible, the safety control coefficient of the operation of the reactor can be improved, and the control precision is high.
As shown in fig. 1 to 3, the entire reactivity control device 100 is located in a region below the core support plate 8. The reactivity control device 100 sequentially comprises a graphite movable block 1, a graphite fixed block 2, a connecting part 3, a container 4, an electromagnetic device 5, a driving part 6 and a supporting component 7 from top to bottom; the top of the container 4 is fixedly connected with the bottom of the graphite fixed block 2, and the top of the container 4 is provided with an opening, so that the graphite movable block 1 can fall into the container 4 through the opening; the top of the connecting part 3 is fixedly connected with the bottom of the graphite movable block 1, the connecting part 3 can be a sliding column structure and sequentially passes through the buffer block 41, the bottom of the container 4, the first plate part 62 and the seat body 64, and the bottom of the connecting part 3 continuously extends relative to the bottom of the seat body 64; therefore, the connecting part 3 can drive the graphite movable block 1 to slide up and down; the driving part 6 is arranged below the container 4, and the motor 61 drives the lead screw 66 to drive the base 64 to move between the first plate part 62 and the second plate part 63 along the guide column 65; when the electromagnetic device 5 is powered on, the first portion 51 of the electromagnetic device 5 is arranged at the bottom of the seat body 64, and the second portion 52 of the electromagnetic device 5 is arranged at the bottom of the connecting portion 3, so that the first portion 51 and the second portion 52 are attracted to each other under the action of electromagnetic force, and thus the seat body 64 and the connecting portion 3 are acted with each other under the action of mutual force, so that when the motor 61 drives the seat body 64 to move, the seat body 64 can drive the connecting portion 3 and the connecting portion 3 to drive the graphite movable block 1 to move together; when the electromagnetic device 5 is powered off, the electromagnetic force between the first portion 51 and the second portion 52 disappears, and the interaction between the seat body 64 and the connecting portion 3 is lost; the support assembly 7 maintains the stability of the device as a whole by being fixedly connected to the ground.
As shown in fig. 1 to 3, the reactivity control apparatus 100 operates as follows: when the reactor is started, the electromagnetic device 5 is electrified, the second part 52 arranged on the seat body 64 and the first part 51 at the bottom of the connecting part 3 are attracted mutually due to the electromagnetic force, so that the mutual force is generated, the motor 61 rotates forwards, the lead screw 66 is driven, the seat body 64 is driven by the lead screw 66 to move upwards along the guide post 65, the seat body 64 drives the connecting part 3, the connecting part 3 drives the graphite movable block 1 to move upwards together at a constant speed until the graphite movable block 1 moves to the bottom of the reactor core, at the moment, the graphite movable block 1 is positioned in the hollow structure of the graphite fixed block 2, and the graphite movable block 1 and the graphite fixed block 2 are jointly used as a bottom reflecting layer, so that the normal operation reactivity of the reactor is maintained; when the reactor needs to stop operating, the motor 61 rotates reversely, the lead screw 66 is driven, so that the lead screw 66 drives the seat body 64 to move downwards along the guide post 65, the seat body 64 drives the connecting part 3 and the connecting part 3 to drive the graphite movable block 1 to move downwards together at a constant speed until the graphite movable block 1 moves into the container 4, the graphite movable block contacts the buffer block 41 and compresses the buffer block 41 and the spring 42, and at the moment, a cavity is formed in the middle of the graphite fixed block 2, so that a large amount of reaction neutrons are leaked to stop the reaction. And when the reactor is powered off accidentally or in need of emergency shutdown, the electromagnetic device 5 is powered off, and the electromagnetic force between the first part 51 and the second part 52 disappears, so that the stress on the connecting part 3 is unbalanced, and the graphite movable block 1 falls rapidly by the gravity of the graphite movable block, leaves the bottom of the reactor core and falls into the container 4 to compress the buffer block 41 and the spring 42.
According to the reactivity control device provided by the embodiment of the invention, according to the neutron leakage principle, when an emergency working condition occurs, the graphite movable block 1 can fall down rapidly by virtue of self weight, so that a large negative reactivity is introduced, the rapid shutdown of a reactor is facilitated, and the safety is ensured. The effective stroke of the movement of the graphite movable block 1, that is, the effective stroke from the lower end surface of the core support plate 8 to the contact with the buffer block 41 and the compression of the buffer block 41 is short, which contributes to further improvement of the control accuracy. Experiments prove that the falling time of the graphite movable block 1 from the bottom of the reactor core is controlled within 1s, and the safety control requirement of the reactor can be met.
A zero power reactor according to an embodiment of the invention comprises the reactivity control apparatus described above. The reactivity control device is used for controlling the zero-power reactor, and is beneficial to developing a plurality of zero-power physical experiments, so that experimental data or accumulated experience is provided for researching reactor characteristics such as shutdown dynamic characteristics under different subcritical degrees, dynamic behavior characteristics introduced by positive and negative reactivity and the like.
Such as a common lead-cooled reactor, in which a core structure is designed, a control rod system, generally including a safety rod and a regulating rod, is disposed on a bottom reflecting layer. Wherein, the safety rod adopts boron carbide and polyethylene as absorbers; the adjusting rod adopts cadmium as an absorber. To further enhance the reliability of reactor reactivity control, reactivity control devices may be positioned below the active area of the reactor core according to safety control redundancy principles. The reactivity control device has a structure and action principle different from that of a control rod, a graphite movable block and a graphite fixed block are jointly used as a bottom reflecting layer of a reactor core, and when the reactor normally operates, the graphite movable block and the graphite fixed block are both positioned at the bottom of the reactor core and play a role in reflecting reaction neutrons; and when taking place emergency operating mode, the graphite movable block can rely on the dead weight to leave reactor core bottom rapidly, and the graphite fixed block forms the cavity in its middle position, introduces negative reactivity for the reactor, and simultaneously, control rod system inserts the reactor core immediately to ensure reactor emergency shut down, guarantee safety.
It should also be noted that, in the case of the embodiments of the present invention, features of the embodiments and examples may be combined with each other to obtain a new embodiment without conflict.
The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and the scope of the present invention is subject to the scope of the claims.
Claims (10)
1. A reactivity control device disposed below an active zone of a reactor core, comprising:
a graphite movable block configured to move to the bottom of the reactor core when the reactor is in operation; when the reactor is shut down, it exits the bottom of the reactor core;
a graphite fixed block surrounding the graphite movable block, the graphite movable block being disposed to be movable relative to the graphite fixed block;
the connecting part is arranged to drive the graphite movable block to move in a direction close to or far away from the bottom of the reactor core;
an electromagnetic device comprising a first portion and a second portion, the first portion and the second portion having an attractive force therebetween when the electromagnetic device is energized;
a drive portion at which the first portion of the electromagnetic device is disposed, the drive portion being configured to drive the first portion in motion;
when the driving part drives the first part to move, the first part drives the second part to move, and the second part drives the connecting part to move, so that the connecting part drives the graphite movable block to move;
when the reactor is powered off accidentally or in need of emergency shutdown, the electromagnetic device is powered off, and the graphite movable block falls down by means of the gravity of the graphite movable block so as to move in the direction far away from the bottom of the reactor core.
2. The reactivity control device according to claim 1,
the reactivity control apparatus further includes a receptacle configured to drop into the receptacle when the movable graphite block is moved in a direction away from the bottom of the reactor core.
3. The reactivity control device according to claim 2,
the container comprises a buffer block and a spring, one end of the spring is connected to the buffer block, and the other end of the spring is connected to the bottom of the container;
the buffer block and the spring are arranged to compress the buffer block and the spring when the graphite movable block falls into the container to contact the buffer block.
4. The reactivity control device according to claim 1,
the driving part comprises a driving component and a motor,
the motor is arranged to rotate in a forward direction to drive the drive assembly to move in a direction towards the bottom of the reactor core when the reactor is in operation; when the reactor is shut down, the motor rotates in the reverse direction to drive the driving assembly to move in a direction away from the bottom of the reactor core.
5. The reactivity control device according to claim 4,
the driving component comprises a first plate part, a second plate part, a base body, a guide post and a lead screw,
the seat body is arranged between the first plate part and the second plate part;
the top end and the bottom end of the guide column are fixedly connected with the first plate part and the second plate part respectively, and the guide column penetrates through the seat body;
the lead screw drives the base body to move between the first plate part and the second plate part along the guide column;
the first part of the electromagnetic device is arranged on the base body.
6. The reactivity control device according to claim 5,
also comprises a supporting component which comprises a top plate, a bottom plate and a supporting column,
the top plate is fixedly connected with the second plate part;
the bottom plate is fixedly connected with the ground;
the support column is supported between the top plate and the bottom plate.
7. The reactivity control device according to claim 5,
the connecting part can slidably penetrate through the first plate part and the seat body;
the second part of the electromagnetic device is arranged at the bottom of the connecting part.
8. The reactivity control device according to claim 5,
the connection part of the graphite movable block and the connecting part is arranged in a centering way relative to the lead screw.
9. The apparatus of claim 1, wherein,
when the graphite movable block moves to the bottom of the reactor core, the graphite movable block and the graphite fixed block are jointly used as a bottom reflecting layer of the reactor core;
when the graphite movable block leaves the bottom of the reactor core, a cavity structure is formed in the middle of the graphite fixed block.
10. A zero power reactor comprising the reactivity control apparatus of any one of claims 1 to 9.
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