A nuclear reactor emergency shutdown control system using shape memory alloy

Abstract

The present invention discloses a nuclear reactor emergency shutdown control system using shape memory alloy, which relates to the field of nuclear engineering safety assurance. The nuclear reactor emergency shutdown control system includes a nuclear reactor, a safety rod group, a shape memory alloy spring and a drive system. The nuclear reactor includes a tube seat and a plurality of fuel rods fixedly connected to the tube seat; the safety rod group includes a plurality of safety rods; the safety rods are inserted between the gaps of the fuel rods; one end of the shape memory alloy spring is connected to the bottom end of the safety rod, and the other end is fixed to the tube seat; the phase change temperature of the shape memory alloy spring is higher than the working temperature of the nuclear reactor; the drive system is connected above the safety rod group to drive the safety rod group to move along the axial direction of the fuel rod. The emergency shutdown control system of the present invention has a simple structure. When an emergency accident occurs, the control system can automatically realize emergency shutdown to ensure the stability and controllability of the nuclear reactor.

Description

Technical Field

[0001] The invention belongs to the field of nuclear engineering safety assurance, and in particular relates to a nuclear reactor emergency shutdown control system using shape memory alloys. Background Art

[0002] With the rapid development of society, the level of science and technology has been continuously improved, but at the same time, it has also brought about problems such as energy shortage. As a clean, efficient and sustainable form of energy, nuclear energy has always attracted much attention. However, while nuclear energy can solve energy problems, it also poses great safety risks. The Chernobyl nuclear accident and the Fukushima nuclear accident have had irreparable impacts on human health and the natural environment.

[0003] At present, nuclear reactors mostly use safety rods to maintain the start or stop of the internal nuclear reaction. However, in an emergency, such as a power outage, the safety rods cannot be driven normally to insert into the nuclear reactor, which will lead to the risk of the nuclear reactor losing control or even exploding, causing immeasurable harm.

[0004] Therefore, it is necessary to design a nuclear reactor emergency shutdown control system using shape memory alloys to solve the above problems and ensure human life safety and environmental health. Summary of the invention

[0005] The purpose of the present invention is to provide a nuclear reactor emergency shutdown control system using shape memory alloys to solve the technical problem in the prior art that nuclear reactors are prone to runaway.

[0006] To achieve the above object, the present invention provides the following solution: a nuclear reactor emergency shutdown control system using shape memory alloy, comprising:

[0007] A nuclear reactor, comprising a tube seat and a plurality of fuel rods fixed to the tube seat;

[0008] A safety rod group, the safety rod group comprising a plurality of safety rods; the safety rods are inserted between the gaps of the fuel rods;

[0009] a shape memory alloy spring, one end of which is connected to the bottom end of the safety rod, and the other end of which is fixed to the tube seat; the phase change temperature of the shape memory alloy spring is higher than the operating temperature of the nuclear reactor;

[0010] A driving system is connected above the safety rod group to drive the safety rod group to move along the axial direction of the fuel rod.

[0011] Preferably, when the nuclear reactor is in normal working condition, the resistance of the shape memory alloy spring in the martensite state is smaller than the resistance of the drive system, and the resistance of the shape memory alloy spring in the austenite state is larger than the resistance of the drive system; when the temperature of the nuclear reactor rises to the phase transition temperature of the shape memory alloy spring, the shape memory alloy spring transforms from martensite to austenite, and at this time the resistance of the shape memory alloy spring is larger than the resistance of the drive system when it is stationary.

[0012] Preferably, the shape memory alloy spring is Ni 56 Mn 25 Ga 18.7 Sr 0.3 、Ni 56 Mn 25 Ga 18.7 Sr 0.3 、Ni 54 Mn 26 Ga 20 、Ti 30 Ni 50 Hf 20 、Ti 50 Ni 13 Pd 37 One or more of the .

[0013] Preferably, the safety rod is made of one of boron, boron carbide, cadmium, and silver indium cadmium.

[0014] Preferably, the driving system comprises a motor driver and a fixed joint connected below the motor driver, and the fixed joint is connected to the safety rod set.

[0015] Preferably, the motor driver comprises a reduction motor, the output end of the reduction motor is transmission-connected to a winding roller, a cable is wound on the winding roller, one end of the cable is fixedly connected to the motor driver, and the other end is connected to the fixed joint.

[0016] Preferably, the reduction motor is driven by electricity.

[0017] Preferably, the fixed joint is made of stainless steel.

[0018] Preferably, the fixed joint is detachably connected to the safety rod set.

[0019] The present invention discloses the following technical effects:

[0020] Compared with the prior art, the nuclear reactor emergency shutdown control system of the present invention is applied to a nuclear reactor. When the reactor is operating normally, the safety rod group can be controlled by the folding drive system to maintain the normal operation of the nuclear reactor. When the safety rod group is inserted into the nuclear reactor, the neutron flow rate is reduced by absorbing neutrons, thereby slowing down or stopping the fission reaction of the nuclear reactor. When an accident occurs in the nuclear reactor, the temperature inside the nuclear reactor rises sharply and an emergency shutdown is required. At this time, the shape memory alloy spring increases its resistance and contracts at high temperature, automatically pulling the safety rod group into the nuclear reactor to achieve an emergency shutdown.

[0021] The emergency shutdown control system of the present invention has a simple structure. When an emergency accident occurs, the control system can automatically realize the emergency shutdown, thereby ensuring the stability and controllability of the nuclear reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 A schematic structural diagram of a nuclear reactor emergency shutdown control system according to an embodiment of the present invention;

[0024] Figure 2 It is an operating state diagram of a nuclear reactor emergency shutdown control system according to an embodiment of the present invention;

[0025] Figure 3 A schematic diagram of the structure of a nuclear reactor in an embodiment of the present invention;

[0026] Figure 4 It is a schematic diagram of the structure of the shape memory alloy spring in an embodiment of the present invention;

[0027] Figure 5 It is a schematic structural diagram of a safety rod assembly in an embodiment of the present invention;

[0028] Figure 6 Schematic diagram of the structure of the motor driver in an embodiment of the present invention.

[0029] Among them, 1. nuclear reactor; 2. shape memory alloy spring; 3. safety rod group; 31. safety rod; 32. bracket; 4. drive system; 41. motor driver; 42. fixed joint. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] Reference Figure 1 and Figure 2 As shown, the present invention provides a nuclear reactor emergency shutdown control system using shape memory alloy, comprising a shape memory alloy spring 2 connected to the bottom of a nuclear reactor 1, a safety rod group 3 connected above the shape memory alloy spring 2, and a drive system 4 located above the safety rod group 3; specifically, as Figure 3 As shown, the nuclear reactor 1 includes a tube base and a plurality of fuel rods; Figure 5 As shown, the drive system 4 includes a motor driver 41 and a fixed joint 42 connected below the motor driver 41; Figure 6 As shown, the safety rod group 3 includes a bracket 32 ​​and a plurality of safety rods 31 suspended at the bottom of the bracket 32. The top of the bracket 32 ​​is suspended on the fixed joint 42 and reciprocates up and down with the operation of the motor driver 41. The shape memory alloy spring 2 is connected between the safety rod 31 and the nuclear reactor 1, with its lower end connected to the tube seat of the nuclear reactor 1 and its upper end connected to the safety rod group 3.

[0033] In the above embodiment, if Figure 5 As shown, the motor driver 41 includes a reduction motor, the output end of the reduction motor is connected to the winding roller, and the winding roller is wound with a cable. One end of the cable is fixedly connected to the motor driver 41, and the other end is connected to the fixed joint 42. The fixed joint 42 is a hook structure, which can be detachably connected to the end of the cable. As the reduction motor runs, the winding roller rotates, and the cable is retracted and released on the winding roller, thereby driving the safety rod group 3 suspended on the fixed joint 42 to reciprocate up and down.

[0034] In a further optimized solution, the material of the safety rod 31 is one of boron, boron carbide, cadmium, and silver indium cadmium. When the safety rod group 3 is inserted into the nuclear reactor 1, the neutron flux is reduced by absorbing neutrons, thereby slowing down or stopping the fission reaction of the nuclear reactor 1.

[0035] Further optimization scheme, such as Figure 4As shown, the shape memory alloy spring 2 is made of a suitable shape memory alloy, and the phase transformation temperature of the shape memory alloy is higher than the operating temperature of the nuclear reactor 1. The operating temperature of the third generation nuclear reactor 1, which is currently the most commonly used, is about 300°C. By comparing the peak temperature of the martensitic phase transformation of shape memory alloys of different materials and the temperature of the typical nuclear reactor 1, the embodiment of the present invention selects the following relatively suitable shape memory alloys:

[0036] Ni 56 Mn 25 Ga 18.7 Sr 0.3 , its martensitic transformation peak temperature is 451°C;

[0037] Ni 55 Mn 25 Ga 18 Ti2, its martensitic transformation peak temperature is 480°C;

[0038] Ni 54 Mn 26 Ga 20 , its martensitic transformation peak temperature is 625℃;

[0039] Ti 30 Ni 50 Hf 20 , its martensitic transformation peak temperature is 700~900℃;

[0040] Ti 50 Ni 13 Pd 37 , and its martensitic transformation peak temperature is 347℃.

[0041] The above-mentioned shape memory alloys will harden at high temperatures, increase their resistance and shrink, and can automatically pull the safety rod group 3 into the nuclear reactor 1 to achieve emergency shutdown.

[0042] It should be understood that other shape memory alloys whose martensitic phase transformation peak temperature exceeds the operating temperature of the nuclear reactor 1 can be used as alternative materials for the shape memory alloy spring 2 of the present invention, and no further limitation is made herein.

[0043] According to a further optimized solution, the reduction motor is driven by electricity.

[0044] According to a further optimized solution, the fixed joint 42 is made of stainless steel.

[0045] The working principle of the embodiment of the present invention is as follows:

[0046] In the nuclear reactor emergency shutdown control system using shape memory alloy of the present invention, when the nuclear reactor 1 is operating normally, the resistance of the shape memory alloy spring 2 in the martensite state (low temperature) is less than the resistance of the motor driver 41, and the resistance of the shape memory alloy spring 2 in the austenite state (high temperature) is greater than the resistance of the motor driver 41. When the nuclear reactor 1 is in an emergency, it cannot be driven by electricity, the temperature of the nuclear reactor 1 rises to the phase transition point temperature of the shape memory alloy spring 2, and the shape memory alloy spring 2 changes from martensite to austenite. At this time, the resistance of the shape memory alloy spring 2 is greater than the resistance of the motor driver 41 when it is stationary, and the shape memory alloy spring 2 pulls the safety rod group 3 into the nuclear reactor 1 to achieve emergency shutdown; when the nuclear reactor 1 is repaired and the power is restored, the motor driver 41 is driven to pull out the safety rod group 3 and continue to operate normally.

[0047] The embodiments of the present invention disclose the following beneficial effects:

[0048] 1. The shape memory alloy spring 2 used in the present invention can harden at high temperatures, increase resistance and shrink. When an unexpected situation occurs in the nuclear reactor 1, causing the internal temperature to increase rapidly and the power system cannot work normally. The shape memory alloy spring 2 can quickly harden and shrink based on its own material properties, automatically pulling the safety rod group 3 into the nuclear reactor 1 to achieve emergency shutdown.

[0049] 2. The present invention has a simple structure, convenient installation, and all materials have strong durability. It has strong economic benefits while ensuring the safety of the nuclear reactor 1.

[0050] 3. Reuse. After the nuclear power plant is repaired, the motor can be restarted to pull out the safety gang and resume normal operation without affecting subsequent normal use.

[0051] The details not described in detail in the present invention are all conventional technical means known to those skilled in the art.

[0052] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0053] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A nuclear reactor emergency shutdown control system using shape memory alloy, characterized in that: include: A nuclear reactor (1), the nuclear reactor (1) comprising a tube seat and a plurality of fuel rods fixedly connected to the tube seat; A safety rod group (3), the safety rod group (3) comprising a plurality of safety rods (31); the safety rods (31) are inserted between the gaps of the fuel rods; A shape memory alloy spring (2), one end of the shape memory alloy spring (2) is connected to the bottom end of the safety rod (31), and the other end is fixed to the tube seat; the phase change temperature of the shape memory alloy spring (2) is higher than the operating temperature of the nuclear reactor (1); the shape memory alloy spring (2) is Ni 56 Mn 25 Ga 18.7 Sr 0.3 、Ni 55 Mn 25 Ga 18 Ti2、Ni 54 Mn 26 Ga 20 、Ti 30 Ni 50 Hf 20 、Ti 50 Ni 13 Pd 37 One or more of the following; a drive system (4), the drive system (4) being connected above the safety rod group (3) and driving the safety rod group (3) to move along the axial direction of the fuel rod; the drive system (4) comprising a motor driver (41) and a fixed joint (42) connected below the motor driver (41), the fixed joint (42) being connected to the safety rod group (3), and the fixed joint (42) being detachably connected to the safety rod group (3); When the nuclear reactor (1) is in normal working condition, the resistance of the shape memory alloy spring (2) in a martensite state is smaller than the resistance of the drive system (4), and the resistance of the shape memory alloy spring (2) in an austenite state is larger than the resistance of the drive system (4); when the temperature of the nuclear reactor (1) rises to the phase transition temperature of the shape memory alloy spring (2), the shape memory alloy spring (2) transforms from martensite to austenite, and at this time, the resistance of the shape memory alloy spring (2) is larger than the resistance of the drive system (4) when it is stationary.

2. The nuclear reactor emergency shutdown control system using shape memory alloy according to claim 1, characterized in that: The material of the safety rod (31) is one of boron, boron carbide, cadmium, and silver indium cadmium.

3. The nuclear reactor emergency shutdown control system using shape memory alloy according to claim 1, characterized in that: The motor driver (41) comprises a reduction motor, the output end of which is drivingly connected to a winding roller, a cable being wound on the winding roller, one end of the cable being fixedly connected to the motor driver (41), and the other end being connected to the fixed joint (42).

4. The nuclear reactor emergency shutdown control system using shape memory alloy according to claim 3, characterized in that: The reduction motor is driven by electricity.

5. The nuclear reactor emergency shutdown control system using shape memory alloy according to claim 1, characterized in that: The fixed joint (42) is made of stainless steel.

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