CN109830315B

CN109830315B - Expanded nuclear reactor core

Info

Publication number: CN109830315B
Application number: CN201910085838.8A
Authority: CN
Inventors: 王翔
Original assignee: Harbin Engineering University
Current assignee: Harbin Engineering University
Priority date: 2019-01-29
Filing date: 2019-01-29
Publication date: 2022-08-02
Anticipated expiration: 2039-01-29
Also published as: CN109830315A

Abstract

The invention provides an expanded nuclear reactor core, belongs to the technical field of nuclear reactors, and particularly relates to an expanded nuclear reactor core. The problem of serious nuclear accidents such as reactor core melting caused by the fact that a reactor cannot stop working in time when cooling substances are lost under the unexpected condition is solved. It comprises a plurality of core block units cut radially and an unfolding device. It is mainly used for realizing the autonomous separation of the reactor core.

Description

Expanded nuclear reactor core

Technical Field

The invention belongs to the technical field of nuclear reactors, and particularly relates to an expanded nuclear reactor core.

Background

In low temperature heat supply reactor or small modular reactor designs, the reactor is wholly immersed in a pool of water. The water in the water pool is used as a final hot trap to provide the safety guarantee of the reactor. However, due to the risk of accidents such as earthquakes, the pool built on the ground surface may crack, resulting in the outflow of water in the pool, so that the reactor system may lose the final heat trap and fail to provide sufficient cooling under the condition that the reactor system may not be stopped in an accident, and further a large amount of heat is generated and cannot be discharged, thereby causing the melting of the reactor core and causing serious nuclear accidents.

Disclosure of Invention

The invention provides an expanded nuclear reactor core for solving the problems in the prior art.

In order to achieve the purpose, the invention adopts the following technical scheme: an expanded nuclear reactor core comprising a plurality of radially split pellet units and an expansion device, the bottom surfaces of the pellet units are hinged with the bottom of the reactor, the plurality of pellet units are polymerized in the radial direction to form a core, the unfolding device comprises a plurality of gathering rods and a restraining component, the number of the gathering rods is the same as that of the core block units, and the gathering rods are fixedly connected with the core block units at corresponding positions, the gathering rods gather together along the central axis of the reactor to form a complete cylinder at the top, the top of the gathering rod is a fastening section, the heat dissipation section of the gathering rod is arranged below the fastening section, the restraint component is positioned at the fastening section of the gathering rod, the restraint assembly is connected with each gathering rod under the action of buoyancy force, so that the gathering rods are tightly connected to realize polymerization of the core block units, and the restraint assembly realizes separation of the core block units under the action of gravity force.

Furthermore, the diameter of the fastening section of the gathering rod is larger than that of the heat dissipation section.

Further, the restraining component is a hoop with a notch, and the hoop is a buoyancy hoop.

Furthermore, the gathering rod fastening section is of a buoyancy tank structure and provides upward buoyancy for the gathering rod.

Furthermore, the restraint assembly is a separation supporting mechanism, the separation supporting mechanism comprises a gravity part and supporting rods, the gravity part is located inside the buoyancy tank structure, the number of the supporting rods is the same as that of the core block units, one end of each supporting rod is hinged to the bottom surface of the gravity part, and the other end of each supporting rod is hinged to the middle section of the gathering rod at the corresponding position.

Still further, the pellet units are either monolithic clad pellets having a common clad or individual clad pellets each having an individual clad.

Furthermore, the top end of the fastening section of the gathering rod is provided with a stop piece.

Furthermore, shutter type protruding radiating fins are arranged on the surface of the radiating section of the gathering rod.

Furthermore, the heat dissipation section of the gathering rod is made of a heat-conducting metal material or is coated with a heat-conducting metal coating.

Further, the fuel in the pellet unit adopts a direct fuel element arrangement structure or a fuel assembly structure.

Compared with the prior art, the invention has the beneficial effects that: the invention adopts an expanded nuclear reactor core structure to solve the problem of serious nuclear accidents such as reactor core melting and the like caused by the fact that the reactor cannot stop working in time when cooling substances are lost under the unexpected condition. A passive and passive shutdown mechanism is introduced, and by means of natural laws such as gravity, buoyancy and the like, manual control and redundant equipment are replaced, so that the reactor can automatically act when loss of cooling substances occurs, the reactor core is unfolded, automatic shutdown is realized, heat dissipation is enhanced, and serious accidents such as reactor core fusion are avoided. The invention does not need manual response and a control system when an unexpected accident happens, realizes complete passive and passive behaviors, simplifies the system and improves the inherent safety of the immersed nuclear reactor.

Drawings

FIG. 1 is a schematic view of a folded-in structure of an unfolded nuclear reactor core restraint assembly of the present invention in the form of a hoop

FIG. 2 is a schematic diagram of the core restraint assembly of an expanded nuclear reactor according to the present invention in an expanded state when the core restraint assembly is a hoop

FIG. 3 is a schematic view of a folded-in configuration of an unfolded nuclear reactor core restraint assembly according to the present invention as a split support mechanism

FIG. 4 is a schematic diagram of a core restraint assembly of an expanded nuclear reactor according to the present invention in an expanded state with the core restraint assembly being a split support mechanism

FIG. 5 is a schematic illustration of an expanded nuclear reactor core according to the present invention in an expanded state

FIG. 6 is a schematic diagram of an expanded nuclear reactor core monolith cladding pellet configuration of the present invention

FIG. 7 is a schematic diagram of an expanded nuclear reactor core individual cladding pellet configuration according to the present invention

1-horizontal plane, 2-stop sheet, 3-hoop, 4-gathering rod, 5-fin, 6-pellet unit, 7-reactor bottom, 8-buoyancy tank, 9-gravity part, 10-support rod, 11-integral clad pellet, 12-independent clad pellet, 13-direct fuel element arrangement structure, 14-fuel assembly structure

Detailed Description

The technical solution in the embodiments of the present invention will be clearly and completely explained below with reference to the drawings in the embodiments of the present invention.

Referring to fig. 1-7 to illustrate the embodiment, an expanded nuclear reactor core comprises a plurality of core block units 6 which are divided along the radial direction and an expanding device, wherein the bottom surface of each core block unit 6 is hinged with the bottom 7 of the reactor, the core blocks 6 are polymerized along the radial direction to form the core, the expanding device comprises a plurality of gathering rods 4 and a restraining component, the number of the gathering rods 4 is the same as that of the core block units 6, the gathering rods 4 are fixedly connected with the core block units 6 at corresponding positions, the gathering rods 4 are gathered together along the axial direction of the reactor to form a complete cylinder, the top of each gathering rod 4 is a fastening section, the heat dissipation section of each gathering rod 4 is arranged below the fastening section, the restraining component is arranged at the fastening section of each gathering rod 4, the restraining component is connected with each gathering rod 4 under the action of buoyancy, so that the gathering rods 4 are tightly connected to realize the polymerization of the core block units 6, the constraining assembly effects the separation of the core units 6 under the action of gravity.

In this embodiment, under a normal operating condition, the entire reactor is immersed in the cooling medium, the plurality of gathering rods 4 gather together along the central axis of the reactor to form a complete cylinder, each pellet unit 6 gathers around the central axis, and the reactor has enough fissile materials in a specified space, so that sufficient neutron flux density can be realized, fission is realized, and the reactor works normally; when the reactor is in an accident condition, the cooling medium is lost, the upper ends of the gathering rods 4 are released from constraint and separated under the action of gravity, so that the core block units 6 are unfolded outwards around the hinged part of the bottom 7 of the reactor, the reactor stops fission due to neutron leakage or insufficient quality of fission substances in a specified space, the reactor stops working, and the automatic shutdown of the reactor is realized.

In this embodiment gather together 4 fastening sections diameters of pole and be greater than the heat dissipation section diameter for strengthen the heat dissipation of reactor core part, do benefit to the restraint subassembly simultaneously and remove the restraint to gathering together pole 4, the restraint subassembly is for the hoop 3 that has the breach, the hoop 3 is the buoyancy hoop, the buoyancy hoop can float up to the fastening section under the buoyancy effect, makes a plurality of poles 4 of gathering together gather together mutually, and when coolant was lost, the liquid level descends, and the buoyancy hoop can float down to breaking away from the fastening section to from 3 breachs of hoop and break away from and gather together pole 4, remove the restraint to gathering together pole 4 and make and gather together the separation of pole 4, reactor stop work.

Gather together 4 fastening sections of pole and for 8 structures of flotation tank, for gathering together pole 4 and provide ascending buoyancy, the restraint subassembly is separation supporting mechanism, separation supporting mechanism includes gravity parts 9 and supporting rod 10, gravity parts 9 is located inside 8 structures of flotation tank, supporting rod 10 quantity is the same with 6 quantity of pellet unit, supporting rod 10 one end is articulated with 9 bottom surfaces of gravity parts, and the other end is articulated with 4 middle sections of pole of gathering together that correspond the position, gravity parts 9 can rely on self gravity to descend, promotes supporting rod 10 and will gather together pole 4 of gathering together and prop open, releases each and gathers together pole 4 and make its separation. When the whole reactor is immersed in the cooling medium, the buoyancy tank 8 structure provides upward buoyancy, and the downward gravity of the gravity component 9 is in a balanced state or slightly larger than the gravity, so that the gathering rod 4 is in a gathering state; when the cooling medium is lost, the liquid level is lowered to cause part of the floating box 8 to be above the liquid level, the buoyancy provided by the floating box 8 is lost or reduced, the gravity provided by the gravity part 9 is larger than the buoyancy generated by the floating box 8, the top gravity part 9 is lowered by the self gravity, the supporting rod 10 is pushed to prop the gathering rods 4 gathered together, and then each pellet unit 6 is separated, so that the automatic shutdown of the reactor is realized. Or under the condition of an accident, the cooling condition of the reactor is deteriorated, the temperature of the cooling medium is increased, the density is reduced, the buoyancy generated by the buoyancy tank 8 is reduced, the gravity provided by the gravity part 9 is also larger than the buoyancy generated by the buoyancy tank 8, the gravity part 9 is lowered, the gathering rod 4 is propped open through the supporting rod 10, each pellet unit 6 is separated, and the automatic shutdown of the reactor is realized. The gathering rod 4 can also adopt an auxiliary fastening mode, and under the normal operation condition, the gathering rod is gathered when the whole reactor is immersed in a cooling medium, so that the disturbance of the system state is reduced; under accident conditions, the liquid level drops or the liquid density decreases, and the gravity provided by the gravity component 9 is enough to expand the auxiliary fastening component, so that the functions are realized.

Based on the above embodiments, the pellet units 6 in this embodiment are either unitary clad pellets 11 having a common cladding or individual clad pellets 12 each having an individual cladding, formed from individual split apart claddings, the fuel within the pellet units 6 being in the form of a direct arrangement of fuel elements 13 or a fuel assembly structure 14, the pellet units 6 preferably equally dividing the reactor core into six in the circumferential direction when the direct arrangement of fuel elements 13 is used; when the fuel assembly structure 14 is used, the pellet units 6 preferably equally divide the reactor core into four in the circumferential direction. Gather together 4 fastening sections tops of pole and be provided with only separation blade 2 for prevent the restraint subassembly slippage, 4 heat dissipation section surfaces of pole of gathering together are provided with the prominent fin 5 of venetian blind formula, are used for increasing heat radiating area, 4 heat dissipation sections of pole of gathering together adopt heat conduction type metal material or adopt heat conduction type metal coating, are used for improving the radiating effect, the restraint subassembly chooses for use light high strength material processing preparation.

The present invention provides an expanded nuclear reactor core, which is described in detail above, and the principle and the implementation of the present invention are explained herein by using specific examples, and the description of the above examples is only used to help understanding the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.

Claims

1. An expanded nuclear reactor core, comprising: the reactor core comprises a plurality of core block units (6) which are cut along the radial direction and an unfolding device, wherein the bottom surfaces of the core block units (6) are hinged with the bottom (7) of a reactor, the core block units (6) are polymerized along the radial direction to form a reactor core, the unfolding device comprises a plurality of gathering rods (4) and restraining components, the number of the gathering rods (4) is equal to that of the core block units (6) and is fixedly connected with the core block units (6) at corresponding positions, the gathering rods (4) are gathered along the central axis of the reactor to form a complete cylinder, the top of each gathering rod (4) is a fastening section, a heat dissipation section of the gathering rod (4) is arranged below the fastening section, the restraining components are arranged at the fastening sections of the gathering rods (4), the restraining components are connected with the gathering rods (4) under the action of buoyancy, so that the gathering rods (4) are tightly connected, and the polymerization of the core block units (6) is realized, the constraining assembly effects the separation of the pellet units (6) under the action of gravity.

2. The expanded nuclear reactor core of claim 1, wherein: the diameter of the fastening section of the gathering rod (4) is larger than that of the heat dissipation section.

3. The expanded nuclear reactor core of claim 2, wherein: the restraint assembly is a hoop (3) with a notch, and the hoop (3) is a buoyancy hoop.

4. The expanded nuclear reactor core of claim 1, wherein: gather together pole (4) fastening section and be flotation tank (8) structure, for gathering together pole (4) and provide ascending buoyancy.

5. The expanded nuclear reactor core of claim 4, wherein: the restraint subassembly is separation supporting mechanism, separation supporting mechanism includes gravity part (9) and supporting rod (10), gravity part (9) are located flotation tank (8) structure inside, supporting rod (10) quantity is the same with pellet unit (6) quantity, supporting rod (10) one end is articulated with gravity part (9) bottom surface, and the other end is articulated with the pole (4) middle section of gathering together that corresponds the position.

6. The expanded nuclear reactor core of claim 1, wherein: the pellet units (6) are either unitary clad pellets (11) having a common cladding or individual clad pellets (12) each having an individual cladding.

7. The expanded nuclear reactor core of claim 2 or 3, wherein: the top end of the fastening section of the gathering rod (4) is provided with a stop piece (2).

8. The expanded nuclear reactor core of any one of claims 1 to 6, wherein: the surface of the heat dissipation section of the gathering rod (4) is provided with a shutter type raised heat dissipation fin (5).

9. The expanded nuclear reactor core of any one of claims 1 to 6, wherein: the heat dissipation section of the gathering rod (4) is made of a heat-conducting metal material or a heat-conducting metal coating.

10. The expanded nuclear reactor core of any one of claims 1 to 6, wherein: the fuel in the pellet unit (6) is in a direct arrangement of fuel elements (13) or in a fuel assembly arrangement (14).