CN117747141A - Lead bismuth pile - Google Patents

Abstract

The embodiment of the invention relates to the technical field of reactivity control of nuclear reactors, in particular to a lead-bismuth reactor, which comprises the following components: a core, safety rods, a stack vessel, and coolant. The reactor core is arranged in a reactor vessel, the safety rod can be inserted into the reactor core to stop the reactor, and the coolant is arranged in the reactor vessel to cool the reactor core. Wherein a space is formed in the stack vessel so that the safety rod does not contact the coolant during insertion into the core. According to the lead-bismuth reactor in the embodiment of the invention, the safety rod is arranged to fall by self gravity and is inserted into the reactor core to stop the reactor, and the safety rod is physically isolated from the coolant, so that the safety rod is prevented from being influenced by buoyancy of the coolant in the falling process and cannot be quickly inserted into the reactor core, the lead-bismuth reactor can realize passive quick reactor stopping under the action of gravity under the accident working condition, and the safety and reliability of the lead-bismuth reactor are improved.

Description

Lead bismuth pile

Technical Field

The embodiment of the invention relates to the technical field of reactivity control of nuclear reactors, in particular to a lead-bismuth reactor.

Background

The statements herein merely provide background information related to the present disclosure and may not necessarily constitute prior art. The nuclear reactor needs to have the capability of rapidly stopping the reactor under the accident working condition, the safety rod and the driving device thereof are arranged in the reactor, and the device capable of rapidly dropping the rod to stop the reactor by driving the safety rod is key equipment for ensuring the safety and the reliability of the reactor.

Disclosure of Invention

The following presents a simplified summary of the application in order to provide a basic understanding of some aspects of the application. It should be understood that this summary is not an exhaustive overview of the application. It is not intended to identify key or critical elements of the application or to delineate the scope of the application. Its purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is discussed later.

An embodiment of the present invention provides a lead bismuth stack, comprising: a core, safety rods, a stack vessel, and coolant. The reactor core is arranged in a reactor vessel, the safety rod can be inserted into the reactor core to stop the reactor, and the coolant is arranged in the reactor vessel to cool the reactor core. Wherein a space is formed in the stack vessel so that the safety rod does not contact the coolant during insertion into the core.

According to the lead-bismuth reactor in the embodiment of the invention, the safety rod is arranged to fall by self gravity and is inserted into the reactor core to stop the reactor, and the space is formed in the reactor container to physically isolate the safety rod from the coolant, so that the safety rod is prevented from being influenced by buoyancy of the coolant in the falling process and cannot be quickly inserted into the reactor core, the lead-bismuth reactor can be enabled to realize passive quick stop under the action of gravity under the accident condition, and the safety and reliability of the lead-bismuth reactor are improved.

Drawings

Other objects and advantages of the present invention will become apparent from the following description of embodiments of the present invention, which is to be read in connection with the accompanying drawings, and may assist in a comprehensive understanding of the present invention.

Fig. 1 is a schematic view of a lead bismuth stack according to an embodiment of the present invention.

Reference numerals illustrate:

10. a core; 20. a safety bar; 30. a stack container; 40. a cooling agent; 50. an upper grid plate; 60. a lower grid plate; 70. a safety rod sleeve; 71. a connecting piece; 80. a mounting member; 90. a cover body; 100. a drive assembly; 101. a driving section; 110. a power member; 120. a clamping member; 130. and a seal.

It should be noted that the drawings are not necessarily to scale, but are merely shown in a schematic manner that does not affect the reader's understanding.

Detailed Description

Exemplary embodiments of the present invention will be described hereinafter with reference to the accompanying drawings. In the interest of clarity and conciseness, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made in order to achieve the developer's specific goals, such as compliance with system-and business-related constraints, and that these constraints will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.

It should be noted here that, in order to avoid obscuring the present invention due to unnecessary details, only the device structures and/or processing steps closely related to the solution according to the present invention are shown in the drawings, while other details not greatly related to the present invention are omitted.

The inventor of the invention discovers that when emergency shutdown is needed under the working condition of lead-bismuth reactor accidents, the safety rod can not be quickly dropped under the action of strong buoyancy of a coolant when the safety rod falls and is inserted into a reactor core, and at present, an auxiliary rod dropping device is generally arranged to add an additional counterweight to the safety rod and is combined with a spring and other parts to assist in rod dropping, but the spring and other parts are easy to lose after long-term use, so that the failure of a shutdown system of the lead-bismuth reactor is easy to cause. In addition, the auxiliary rod falling devices occupy additional space, which is unfavorable for miniaturization of the lead-bismuth stack.

Based on this, an embodiment of the present invention provides a lead bismuth stack, as shown in fig. 1, which shows a schematic structural view according to the lead bismuth stack, including: the core 10, the safety bars 20, the stack vessel 30, and the coolant 40. The reactor core 10 is disposed in the reactor vessel 30, the safety rod 20 is disposed so as to be inserted into the reactor core 10 to stop the reactor, and the coolant 40 is disposed in the reactor vessel 30 to cool the reactor core 10. Wherein a space is formed in the stack vessel 30 so that the safety rod 20 does not contact the coolant 40 during insertion into the core 10.

According to the lead-bismuth reactor in the embodiment of the invention, the safety rod 20 is arranged to fall by self gravity and is inserted into the reactor core 10 to stop the reactor, and the space is formed in the reactor vessel 30 to physically isolate the safety rod 20 from the coolant 40, so that the safety rod 20 is prevented from being influenced by the buoyancy of the coolant 40 in the falling process and cannot be quickly inserted into the reactor core 10, the lead-bismuth reactor can be passively and quickly stopped under the action of gravity under the accident condition, and the safety and reliability of the lead-bismuth reactor are improved.

In this embodiment, the stack container 30 is configured to contain the coolant 40 and form a loop safety boundary for the lead bismuth stack to contain the radioactive material to avoid radioactive leakage.

In some embodiments, the safety rod 20 may be a single rod, or a bundle of a plurality of single rods, and the material comprising the safety rod 20 may be a neutron absorbing material, such as boron carbide, or the like.

In some embodiments, the lead bismuth stack may further include an upper grid 50, a lower grid 60, and a safety bar sleeve 70. The reactor core 10 is fixed between the upper grid plate 50 and the lower grid plate 60, the cavity of the safety rod sleeve 70 forms a space, one end of the safety rod sleeve 70 is fixed on the lower grid plate 60, the other end of the safety rod sleeve 70 extends to be higher than the coolant liquid level above the upper grid plate 50, the safety rod sleeve 70 is inserted into the reactor core 10 to isolate the coolant 40, the coolant 40 is prevented from entering the inside of the safety rod sleeve 70, and the safety rod 20 is inserted into the safety rod sleeve 70 because the inside of the safety rod sleeve 70 is not provided with the coolant, so that the safety rod 20 is prevented from being quickly inserted into the reactor core 10 under the buoyancy of the coolant 40 when falling, and the safety of the lead-bismuth stack is ensured.

The upper grid 50 in this embodiment provides a compressive force to the core 10, the lower grid 60 serves to support the core 10 to limit the core 10 under the combined action of the upper and lower grids 50 and 60, and the upper and lower grids 50 and 60 serve to provide a flow path for the coolant 40, the coolant 40 flowing in through the lower grid 60 and out of the upper grid 50.

In some embodiments, the safety rod sleeve 70 is provided in the same configuration as the fuel assembly thimble of the core 10 so that the safety rod sleeve 70 may be inserted into the interior of the core 10 like a fuel assembly, i.e., the safety rod sleeve 70 may be fixedly configured to hold one fuel assembly like a fuel assembly, thereby avoiding redesign of the structure of the core.

In some embodiments, a predetermined gap is left between the safety rod 20 and the safety rod sleeve 70 as the safety rod 20 drops into the safety rod sleeve 70. Since the safety rod sleeve 70 is inserted into the reactor core 10 and is easily deformed due to the too high temperature of the reactor core 10, the embodiment is configured such that when the safety rod 20 falls into the safety rod sleeve 70, a predetermined gap is left between the safety rod 20 and the safety rod sleeve 70, so as to avoid affecting the falling of the safety rod due to the deformation of the safety rod sleeve 70, and thus the reactor cannot be shut down in time. For example, the inner diameter of the safety rod sleeve 70 may be made slightly larger than the outer diameter of the safety rod 20.

In some embodiments, the safety rod sleeve 70 is open at the top in air communication with the in-stack air cavity and the safety rod sleeve 70 is closed at the bottom to prevent the coolant 40 from entering the interior of the safety rod sleeve 70, physically isolating the safety rod sleeve 70 from the coolant 40.

In this embodiment, the safety bar sleeve 70 may be provided as a cylindrical container with an opening formed in an upper portion thereof and a bottom seal, the cylindrical container being provided to be capable of extending above the level of the coolant 40 to physically isolate the safety bar sleeve 70 from the coolant 40. Illustratively, the cylindrical vessel may be configured in a cylindrical shape or in the same hexagonal cylindrical shape as the fuel assembly thimble tubes of the core 10.

Further, the bottom of the safety rod sleeve 70 may be fixedly connected to the lower grid plate 60, so as to avoid the safety rod sleeve 70 from floating up due to the buoyancy of the coolant 40, which results in the safety rod 20 not being inserted into the core 10 under accident conditions, and thus not being shutdown in time.

Specifically, in some embodiments, the safety bar sleeve 70 includes: the connecting piece 71, the connecting piece 71 is connected to the bottom of the safety bar sleeve 70, and the safety bar sleeve 70 is fixedly connected with the lower grid plate 60 through the connecting piece 71. For example, the safety bar sleeve 70 may be welded or snap-fit with the lower grid 60.

In some embodiments, the safety bar sleeve 70 may be made of corrosion-resistant steel, so as to improve the durability and reliability of the safety bar sleeve 70, thereby ensuring the safety of the lead-bismuth stack, and simultaneously, reducing the replacement frequency of the safety bar sleeve 70 and saving the cost.

Also, the safety bar sleeve 70 may be provided with a thickness, in particular, a thickness that is sufficient to ensure that it has sufficient mechanical strength when used in high temperature, highly radioactive and highly corrosive environments, while ensuring that it does not have a significant impact on the reactive value of the safety bar.

In some embodiments, the fuel assemblies, upper grid plates 50, lower grid plates 60, and safety bar sleeves 70 of the core 10 are provided as an integral module to facilitate installation and removal while facilitating flexible layout within the lead bismuth stack, improving utilization efficiency of space within the lead bismuth stack.

In some embodiments, the lead bismuth stack may further comprise: and a mounting member 80. The mounts 80 are provided for assembling the fuel assemblies of the core 10, the upper grid 50, the lower grid 60, and the safety rod sleeve 70 into an integral module. Specifically, in installing the devices and components within the lead bismuth stack, the fuel assemblies of the core 10, the upper grid 50, the lower grid 60, and the safety bar sleeve 70 may be installed into the mounts 80 in a predetermined order, forming an integral module, and installed in the stack vessel 30 in the form of an integral module. By way of example, the mount 80 may be a basket or the like.

In some embodiments, the lead bismuth stack may further comprise: a cover 90. The cover 90 is disposed on top of the stack container 30 and connected to the stack container 30, and the cover 90 is used for closing the stack container 30 to avoid radioactive leakage and ensure the air tightness of the stack container 30.

In some embodiments, the lead bismuth stack may further comprise: the driving assembly 100 and the power member 110 are disposed above the stack container 30, the driving assembly 100 clamps the safety rod 20, the power member 110 is disposed to be connected with the driving assembly 100, the power member 110 drives the driving assembly 100 to move along the extending direction of the safety rod 20, the driving assembly 100 drives the safety rod 20 to move along the extending direction thereof so as to be inserted into the core 10 or to be lifted out of the core 10, and in an accident state, the driving assembly 100 loses the clamping effect on the safety rod 20, and the safety rod 20 freely falls, for example, the power member 110 can be a motor so as to provide power for the driving assembly 100. The drive assembly 100 and power components 110 operate and control the safety rod 20 to be inserted into or removed from the core under normal operating conditions. In some embodiments, the drive assembly may include a gripper that grips the safety bar, the gripper losing grip on the safety bar during an accident condition so that the safety bar falls freely.

In some embodiments, the drive assembly 100 may include: a gear, a rack and a driving part 101. The gear is engaged with the rack, the rack is connected to one end of the driving unit 101, and the other end of the driving unit 101 penetrates the cover 90 and extends into the stack container 30. The gear in the driving assembly 100 rotates to drive the rack to move up and down, so as to drive the driving part 101 to move up and down.

In some embodiments, the lead bismuth stack may further comprise: and a holder 120, wherein one end of the holder 120 is connected to the driving unit 101, and the other end is capable of holding the safety bar 20. When the lead bismuth reactor normally operates, the gear and the rack in the driving assembly 100 drive the driving part 101 to move upwards, so as to drive the clamping piece 120 to move upwards, lift the safety rod 20 to the upper part of the reactor core 10, and under the accident working condition, the clamping piece 120 releases the safety rod 20, so that the safety rod 20 falls into the reactor core 10 under the action of self gravity, and the quick shutdown is realized.

In some embodiments, the driving part 101 may be provided in a rod shape.

In this embodiment, when the lead bismuth stack is operating normally, the safety rod 20 is lifted above the core 10 under the action of the driving assembly 100 and the clamping member 120, the safety rod 20 is not affected by the high temperature of the core 10, and the residual heat after the rapid shutdown is performed under the accident condition is also less, so that a separate cooling system is not required to be arranged for the safety rod 20 to cool the safety rod, and the thermal design requirement of the lead bismuth stack can be satisfied.

In some embodiments, the lead bismuth stack may further comprise: the seal 130 is provided in the cover 90, and the drive unit 101 is hermetically inserted into the seal 130 in accordance with the shape and size of the drive unit 101. The seal 130 serves to ensure the airtight of the stack container 30, avoiding the occurrence of radioactive leakage.

In some embodiments, the lead bismuth stack may further comprise: the auxiliary rod falling device is used as an auxiliary device for driving the safety rod 20 to rapidly fall into the reactor core 10, an energy storage mechanism such as a spring is contained in the auxiliary rod falling device, and under the condition that the safety rod sleeve 70 is damaged or cannot be fixedly connected with the lower grid plate 60 so that the safety rod 20 cannot rapidly fall into the reactor core 10, the safety rod 20 can fall under the action of the auxiliary rod falling device, so that shutdown is realized, and the safety of a lead-bismuth reactor is further ensured.

In some embodiments, the lead bismuth stack may further comprise: the buffer device is used for avoiding rebound of the safety rod 20 caused by impact force when the safety rod 20 falls into the reactor core 10, ensuring that the safety rod 20 can fall to a preset position rapidly, and accordingly achieving rapid shutdown.

It should also be noted that, in the embodiments of the present invention, the features of the embodiments of the present invention and the features of the embodiments of the present invention may be combined with each other to obtain new embodiments without conflict.

The present invention is not limited to the above embodiments, but the scope of the invention is defined by the claims.

Claims (10)

1. A lead bismuth stack characterized in that it comprises: a reactor core, safety bars, a reactor vessel, coolant,

the core is disposed within the stack vessel,

the safety rod is arranged to be inserted into the reactor core for shutdown;

the coolant is disposed in the stack vessel to cool the core,

wherein a space is formed in the stack vessel so that the safety rod does not contact the coolant during insertion into the core.

2. The lead bismuth stack according to claim 1, further comprising an upper grid, a lower grid,

the core is secured between the upper grid and the lower grid,

and also comprises a safety rod sleeve, the hollow cavity of the safety rod sleeve forms the space,

one end of the safety rod sleeve is fixed on the lower grid plate, the other end of the safety rod sleeve extends to be higher than the liquid level of the coolant above the upper grid plate, and the safety rod sleeve is inserted into the reactor core.

3. The lead bismuth stack of claim 2, wherein the safety rod sleeve is provided in the same configuration as a fuel assembly thimble of the core.

4. The lead bismuth stack of claim 2, wherein a predetermined gap is left between the safety bar and the safety bar sleeve as the safety bar falls into the safety bar sleeve.

5. The lead bismuth stack according to claim 2, wherein the safety bar sleeve is open at the upper portion and is in air communication with the in-stack air cavity, and the safety bar sleeve is closed at the bottom.

6. The lead bismuth stack of claim 2, wherein the fuel assemblies, upper grids, lower grids, and safety bar sleeves of the core are provided as an integral module.

7. The lead bismuth stack as claimed in any one of claims 2 to 6, further comprising a buffer device provided at the bottom of the safety bar sleeve, the safety bar acting with the buffer device to prevent the safety bar from being sprung up when the safety bar falls down to the safety bar sleeve.

8. The lead bismuth stack of claim 1, further comprising a drive assembly and a power member, the drive assembly and the power member being disposed above the stack vessel, the drive assembly gripping the safety bar, the power member driving the drive assembly to move along the safety bar extension direction, the drive assembly driving the safety bar to move along its extension direction to insert or raise it out of the core, and in an accident situation, the drive assembly losing grip on the safety bar, the safety bar falling freely.

9. The lead bismuth stack of claim 8, wherein the drive assembly includes a grip that grips the safety bar.

10. The lead bismuth stack according to claim 8, further comprising a cover disposed on the stack container to form a seal with the stack container,

the drive assembly is disposed through the cover and a seal is disposed at a location through the cover such that a seal is formed therebetween.