Nuclear reactor coolant passive ammonification device and ammonification method thereof

Abstract

The invention discloses a nuclear reactor coolant passive ammonia adding device and an ammonia adding method thereof.The nuclear reactor coolant passive ammonia adding device comprises a base, an inflation seat, a piston, an inflation switch and a reset assembly; a fusion cavity which is communicated with a coolant system pipeline and is connected with a coolant fused with ammonia gas is formed in the base, and the inflation seat is arranged on the base; the piston is slidably connected with the interior of the inflation seat, an inflation cavity communicated with the fusion cavity is defined by the piston and the inflation seat, and a first opening is formed in the inflation seat. The passive ammonification device controls the content of radiolysis oxygen in a coolant system pipeline through a self-deceleration ammonification strategy by utilizing the physical principle that the two-phase diffusion rate is continuously reduced, so that the generation of gas products such as hydrogen and nitrogen is reduced, the equipment is protected to a certain extent, and the service life of the equipment is prolonged. And moreover, the total amount of ammonia gas consumed during operation is also reduced, and the reliability of the device is also improved due to the passive design.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear power water treatment, in particular to a passive ammonia addition device for a nuclear reactor coolant and an ammonia addition method thereof. Background Art

[0002] Nuclear power plants face the challenge of core radiation compared to conventional thermal power plants. Coolant radiolysis continuously produces corrosive substances such as oxygen and hydrogen peroxide, causing changes in water quality and threatening the safety of vulnerable structures in the coolant circuit. Chemical deoxygenation solutions used in reactors include the addition of hydrogen (H2), ammonia (NH3), or hydrazine (N2H4) to the coolant. Ammonia is often used as a pH controller and reducing agent in chemical deoxygenation due to its safety, cost-effectiveness, and ability to regulate pH to mitigate corrosion.

[0003] Traditional ammonia dosing strategies are mainly divided into two categories: one-time dosing and continuous dosing. Some specialized nuclear reactors use a one-time dosing strategy before startup, relying on sufficient ammonia to maintain deoxygenation throughout operation.

[0004] However, this approach lacks pH control capabilities due to ammonia depletion in the later stages. Another continuous ammonia addition strategy relies on chemical and volumetric control systems to continuously inject diluted ammonia for control, coupled with automated measurement and control devices. However, this approach leads to a continuous increase in the concentration of ammonia-containing reaction gas products, such as hydrogen and nitrogen. Furthermore, the introduction of detection and control devices under conditions of long-term radiolysis and oxygen production increases overall complexity and operational costs. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a passive ammonia addition device for a nuclear reactor coolant and an ammonia addition method thereof.

[0006] The technical solution adopted by the present invention to solve its technical problems is: to construct a passive ammonia adding device for nuclear reactor coolant, comprising: a base, an inflation seat, a piston, an inflation switch and a reset assembly; a fusion cavity is provided in the base for connecting the coolant system pipeline with the coolant fused with ammonia, and the inflation seat is provided on the base; the piston is slidably connected to the interior of the inflation seat, and the inflation seat surrounds an inflation cavity connected to the fusion cavity, and a first opening is provided on the inflation seat; the inflation switch is provided between the first opening and the inflation cavity, and is provided with a second opening; the reset assembly is installed between the piston and the inflation seat; the ammonia adding device includes an inflation state and a cut-off state switched according to the pressure in the inflation cavity; in the inflation state, the first opening is connected to the second opening to connect the ammonia in the inflation pipe to the inflation cavity; in the cut-off state, the first opening and the second opening are offset and cut off to isolate the inflation pipe from the inflation cavity.

[0007] Furthermore, a first slide groove is provided on the inflation seat, and the inflation switch includes: a slider and a slide plate; the slider is fixedly installed on one side of the piston; the slide plate is slidably connected in the first slide groove, and a damping member is provided between the slide plate and the first slide groove; a second slide groove is provided on the slide plate, and the slider is slidably connected in the second slide groove; a second opening is provided on the slide plate; when the piston moves, the slide plate is driven to move by the slider so that the second opening is connected to the first opening or is offset and cut off.

[0008] Furthermore, the damping member is a sealing ring, felt or interference fit.

[0009] Furthermore, the inflatable seat includes: a hollow inflatable sleeve and an end cover, one end of the inflatable sleeve is sealed with the base, and the end cover is detachably mounted on the other end of the inflatable sleeve.

[0010] Furthermore, the reset assembly includes an elastic member installed between the end cover and the piston.

[0011] Furthermore, the end cover is mounted on the inflatable sleeve through a threaded pair, and the reset assembly also includes a first limit member and a second limit member that are rotatably connected to the end cover and the piston respectively, and both ends of the elastic member are respectively mounted on the first limit member and the second limit member.

[0012] Furthermore, the base includes: at least one connecting tube and a diffusion chamber, the two ends of the connecting tube are respectively connected to the coolant system pipeline to connect the coolant and output it after the coolant and the ammonia are fused; the diffusion chamber is arranged between the inlet and outlet of the connecting tube to fuse the connected ammonia with the coolant.

[0013] Furthermore, the diameter of the fusion cavity is larger than the diameter of the connecting tube; and the cross-sectional area of the fusion cavity on one side close to the inflation seat is larger than the cross-sectional area on the other side away from the inflation seat.

[0014] The present invention also provides a method for passively adding ammonia to a nuclear reactor coolant, comprising the following steps:

[0015] S1. The above-mentioned nuclear reactor coolant passive ammonia adding device is connected to the coolant system pipe;

[0016] S2. One end of the inflation tube is connected to the first opening, and the other end of the inflation tube is connected to the external ammonia gas;

[0017] S3. Ammonia is automatically filled into the inflatable chamber through the inflatable tube, and the pressure difference is used to drive the piston through the slider to move the slider to one end away from the base to reach the cutoff state;

[0018] S4. As the ammonia in the inflatable chamber merges with the coolant in the fusion chamber, the pressure difference is used to move the piston through the slider to move the slide closer to the base to reach the inflated state;

[0019] S5. Repeat the above steps S3 and S4 until all the ammonia in the outside is consumed, and then add ammonia again; or continue to fill the closed space with ammonia.

[0020] Furthermore, the cut-off state in step S3 is specifically that the ammonia gas filled into the inflation chamber will move the piston toward the end away from the base, so that the piston drives the slider to slide in the second slide groove toward the end away from the base; until the slider moves to the end of the slide away from the base, the piston that continues to move drives the second opening on the slide to be dislocated with the first opening through the slider and is cut off.

[0021] Furthermore, the inflation state in step S4 is specifically as follows: as the ammonia in the fusion chamber and the inflation chamber fuses with the coolant, the piston moves toward the end close to the base, causing the piston to drive the slider to slide in the second slide groove toward the end close to the base; until the slider moves to the end of the slide plate close to the base, the piston continues to move through the slider to drive the second opening on the slide plate to connect with the first opening, and the external ammonia automatically fills the inflation chamber with ammonia through the inflation tube.

[0022] Furthermore, in the inflated state, when the pressure of the fusion chamber and the inflation chamber and the elastic force of the elastic member are greater than the external pressure, the piston slowly moves away from the base as the ammonia content increases; until the slider moves to the end of the slide away from the base, driving the second opening on the slide to be dislocated and cut off from the first opening; or, when the pressure of the fusion chamber and the inflation chamber and the elastic force of the elastic member are equal to or less than the external pressure, the piston remains stationary at the end close to the base, and external ammonia continuously enters the fusion chamber and the inflation chamber through the connection between the second opening and the first opening.

[0023] The implementation of the present invention has the following beneficial effects:

[0024] The present application uses a fusion cavity and an inflation cavity to allow the ammonia in the fusion cavity and the inflation cavity to always be in contact with and fused with the coolant, so that the coolant can always automatically and fully fuse with the ammonia, making the ammonia content in the coolant more uniform and avoiding waste of ammonia. The passive ammonia addition device uses the physical principle of the continuous decrease in the two-phase diffusion rate to control the radiolytic oxygen content in the coolant system pipeline through a self-deceleration ammonia addition strategy, thereby reducing the production of gaseous products such as hydrogen and nitrogen, playing a certain protective role on the equipment, and the total amount of ammonia consumed during operation is also reduced. The passive design also increases the reliability of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solution of the present invention, the present invention will be further described below with reference to the accompanying drawings and embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0026] In the attached figure:

[0027] Figure 1 This is a schematic structural diagram of a passive ammonia addition device for a nuclear reactor coolant provided by an embodiment of the present invention;

[0028] Figure 2 This is a cross-sectional view of a passive ammonia addition device for a nuclear reactor coolant provided by an embodiment of the present invention;

[0029] Figure 3 This is an exploded view of the structure of a passive ammonia addition device for a nuclear reactor coolant provided by an embodiment of the present invention;

[0030] Figure 4 Schematic diagram of the structure of the inflation switch provided by an embodiment of the present invention;

[0031] Figure 5 The present invention provides a flow chart of a method for passively adding ammonia to a nuclear reactor coolant.

[0032] Description of the marks in the figure

[0033] Base 1, fusion chamber 11, connecting tube 12, diffusion chamber 13, inflation seat 2, inflation chamber 21, first opening 22, first slide groove 23, inflation sleeve 24, end cover 25, piston 3, inflation switch 4, slider 41, slide plate 42, damping member 43, second slide groove 44, second opening 45, reset assembly 5, elastic member 51, first limit member 52, second limit member 53, coolant system pipeline 6. DETAILED DESCRIPTION

[0034] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific embodiments of the present invention are now described in detail with reference to the accompanying drawings. In the following description, it should be understood that the directions or positional relationships indicated by "front", "back", "up", "down", "left", "right", "longitudinal", "horizontal", "vertical", "horizontal", "top", "bottom", "inside", "outside", "head", "tail", etc. are based on the directions or positional relationships shown in the accompanying drawings and are constructed and operated in specific directions. They are only for the convenience of describing the technical solution and do not indicate that the devices or components referred to must have specific directions. Therefore, they should not be understood as limiting the present invention.

[0035] It should also be noted that, unless otherwise clearly specified and limited, terms such as "installed", "connected", "connected", "fixed", and "set" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. When an element is referred to as being "on" or "under" another element, the element can be "directly" or "indirectly" located on the other element, or there may be one or more intervening elements. The terms "first", "second", "third", etc. are only for the convenience of describing the present technical solution, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second", "third", etc. may explicitly or implicitly include one or more of such features. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0036] In the following description, specific details such as particular system structures and techniques are provided for purposes of illustration, not limitation, to facilitate a thorough understanding of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

[0037] See also Figures 1-4A first embodiment of the present invention discloses a passive ammonia dosing device for a nuclear reactor coolant, comprising: a base 1, an inflation seat 2, a piston 3, an inflation switch 4, and a reset assembly 5. The base 1 is provided with a fusion chamber 11, which communicates with a coolant system pipeline 6 and receives coolant fused with ammonia. The inflation seat 2 is mounted on the base 1. The piston 3 is slidably connected to the interior of the inflation seat 2 and, together with the inflation seat 2, encloses an inflation chamber 21 that communicates with the fusion chamber 11. The inflation seat 2 is provided with a first opening 22. The inflation switch 4 is disposed between the first opening 22 and the inflation chamber 21 and has a second opening 45. The reset assembly 5 is mounted between the piston 3 and the inflation seat 2. The ammonia dosing device has an inflating state and a shutoff state, which are switched according to the pressure within the inflation chamber 21. In the inflating state, the first opening 22 communicates with the second opening 45, allowing ammonia gas from the inflation pipe to enter the inflation chamber 21. In the shutoff state, the first opening 22 and the second opening 45 are offset and blocked, isolating the inflation pipe from the inflation chamber 21.

[0038] The present application provides a fusion chamber 11 within the base 1, which is connected to the coolant system pipeline 6 and receives the coolant fused with ammonia. The inflatable seat 2 is disposed on the base 1. The piston 3 is slidably connected to the interior of the inflatable seat 2, and the inflatable seat 2 encloses an inflatable chamber 21 that is connected to the fusion chamber 11. The inflatable seat 2 is provided with a first opening 22. The inflatable switch 4 is disposed between the first opening 22 and the inflatable chamber 21 and is provided with a second opening 45. The reset assembly 5 is installed between the piston 3 and the inflatable seat 2. After closing the valves on both sides of the coolant system pipeline 6, the base 1 is installed in the coolant system pipeline 6 through the flange, and then the inflation chamber 21 and the fusion chamber 11 are inflated through the first opening 22 and the second opening 45. After the ammonia fills the inflation chamber 21 and the fusion chamber 11, the first opening 22 and the second opening 45 are offset and cut off, so that the inflation chamber 21, the fusion chamber 11 and the coolant system pipeline 6 remain sealed. Then, the valves on both sides of the coolant system pipeline 6 are opened to allow the coolant to pass through the fusion chamber 11 inside the base 1. During the passage of the coolant, the coolant will merge with the ammonia in the inflation chamber 21 and the fusion chamber 11, causing the ammonia in the inflation chamber 21 and the fusion chamber 11 to slowly decrease. As the ammonia decreases, the pressure inside the inflation chamber 21 will decrease, causing the piston 3 to slowly approach the base 1 as the ammonia content decreases, making the volume of the inflation chamber 21 smaller and smaller.

[0039] When the piston 3 moves to the lowest end of the inflation seat 2 close to the base 1, the first opening 22 and the second opening 45 are connected, and the external ammonia gas will enter the inflation chamber 21 through the first opening 22 and the second opening 45, and the entered ammonia gas will continue to merge with the passing coolant. When the rate of the incoming ammonia gas is the same as the rate of fusion of the coolant, the piston 3 will remain stationary, so that the first opening 22 and the second opening 45 are continuously connected. When the rate of the incoming ammonia gas is greater than the rate of fusion of the coolant, the incoming ammonia gas will slowly increase the pressure inside the inflation chamber 21, causing the piston 3 to slowly move away from the base 1. During the movement of the piston 3, the first opening 22 and the second opening 45 continue to be connected, so that ammonia gas continues to enter the inflation chamber 21. When the piston 3 moves to the top, the second opening 45 will be offset and cut off from the first opening 22, so that the fusion chamber 11, the inflation chamber 21 and the coolant system pipe 6 are sealed again. After sealing, the ammonia in the fusion chamber 11 and the inflation chamber 21 continue to fuse with each other as the coolant passes through, and the above steps are repeated. The entire process proceeds spontaneously, and it is only necessary to set up ammonia in communication with the first opening 22 on the outside. This reduces energy loss and has low production costs. By automatically fusing ammonia with the coolant, the phenomenon of excessive ammonia content in the coolant can be reduced, avoiding the waste of ammonia. When the coolant cannot fuse with excessive ammonia, the ammonia can be stored in the inflation chamber 21 first, further reducing the loss of ammonia and making the ammonia content in the coolant more suitable.

[0040] Among them, the reset component 5 installed between the piston 3 and the inflation seat 2 can exert a certain pulling force during the rising process of the piston 3. The generated pulling force is equal to the gravity of the piston 3, so that the piston 3 can be raised when the fusion rate of ammonia is less than the introduction rate of ammonia, thereby improving the sensitivity of the entire device. In the process of introducing ammonia, the content of ammonia fused into the coolant is minimized to make its content more uniform, thereby avoiding waste of ammonia.

[0041] Among them, since the fusion chamber 11 and the inflation chamber 21 remain sealed in the cut-off state, as the ammonia and the coolant fuse, the piston 3 will slowly move downward, making the space of the inflation chamber 21 smaller and smaller, so that the ammonia in the fusion chamber 11 and the inflation chamber 21 can always be in contact with and fused with the coolant, making the ammonia content in the coolant more uniform and avoiding waste of ammonia.

[0042] In some embodiments, the first opening 22 is connected to one end of the inflation tube, and the other end of the inflation tube is connected to an ammonia storage tank. Ammonia is pumped into the first opening 22 through the ammonia storage tank and the inflation tube. When the first opening 22 is connected to the second opening 45, the ammonia automatically enters the inflation cavity 21. This allows for the storage of a large amount of ammonia, allowing the inflation cavity 21 to be quickly filled with ammonia, allowing the first opening 22 and the second opening 45 to be offset and cut off again, thereby avoiding the occurrence of low ammonia content in the coolant, achieving a faster reaction, and being suitable for a wider range of usage environments.

[0043] In some embodiments, a sealing cover can be wrapped around the inflatable seat 2, so that the interior of the sealing cover is connected to the first opening 22 and the inflation tube, and the sealing cover is filled with ammonia. After the first opening 22 and the second opening 45 are connected, the ammonia in the sealing cover will enter the inflation chamber 21 through the inflation tube, the first opening 22 and the second opening 45, filling the inflation chamber 21 with ammonia. The entire device is carried out spontaneously, further saving energy. The sealing cover facilitates installation and filling of ammonia, and can be used in remote locations. The sealing cover can adopt a flexible structure, which can be applied to more installation environments and can also allow all the ammonia in the sealing cover to enter the inflation chamber 21, further reducing the loss of ammonia. The passive ammonia addition device utilizes the physical principle of the continuous reduction of the two-phase diffusion rate and controls the radiolytic oxygen content in the coolant system pipe 6 through a self-decelerating ammonia addition strategy. Compared with the one-time ammonia addition strategy, it also has a pH control function to reduce the corrosive environment. Compared with the continuous ammonia addition strategy, it reduces the production of gaseous products such as hydrogen and nitrogen, plays a certain protective role for the equipment. In addition, the total amount of ammonia consumed during operation is also reduced. The passive design also increases the reliability of the device.

[0044] See also Figures 1-4 In some embodiments, the inflation seat 2 is provided with a first chute 23, and the inflation switch 4 includes a slider 41 and a plate 42. The slider 41 is fixedly mounted on one side of the piston 3, and the plate 42 is slidably connected to the first chute 23. A damping member 43 is provided between the slider 42 and the first chute 23. The plate 42 is provided with a second chute 44, and the slider 41 is slidably connected to the second chute 44. The plate 42 has a second opening 45. When the piston 3 moves, the slider 41 drives the plate 42 to move, so that the second opening 45 is connected to the first opening 22 or is disconnected from the first opening 22.

[0045] In this application, a first slide groove 23 is provided on the inflation seat 2, and the inflation switch 4 includes: a slider 41 and a slide plate 42, the slider 41 is installed on the piston 3, the slide plate 42 is slidably connected in the first slide groove 23, a damping member 43 is provided between the slide plate 42 and the first slide groove 23, a second slide groove 44 is opened on the slide plate 42, and the slider 41 is slidably connected in the second slide groove 44. In the cut-off state, the slide 42 is located at the end of the first slide groove 23 away from the base 1. As the ammonia and the coolant merge, the piston 3 slowly moves toward the base 1. During the movement, the slider 41 will be driven to move in the second slide groove 44. Since a damping member 43 is provided between the slide 42 and the first slide groove 23, the slide 42 and the first slide groove 23 will remain relatively stationary. The second opening 45 opened on the slide 42 is always offset and cut off from the first opening 22. When the piston 3 drives the slider 41 to move to the end of the second slide groove 44 close to the base 1, the piston 3 will drive the slide 42 on the first slide groove 23 through the slider 41 to overcome the resistance of the damping member 43 and move closer to the base 1 until the second opening 45 on the slide 42 is connected to the first opening 22, and the piston 3 remains stationary.

[0046] Afterwards, the inflated state is reached, and external ammonia enters the inflation chamber 21 through the second opening 45 and the first opening 22. When the ammonia introduction rate is equal to or less than the fusion rate, the piston 3 remains stationary, and the second opening 45 and the first opening 22 remain connected. External ammonia continuously enters the inflation chamber 21, increasing the ammonia content in the coolant. When the ammonia introduction rate is greater than the fusion rate, the ammonia content in the inflation chamber 21 increases, increasing its pressure, and the piston 3 slowly moves away from the base 1. During this movement, due to the damping member 43 provided between the slide 42 and the first slide 23, the piston 3 only drives the slider 41 to move upward in the second slide 44 on the slide 42. During this process, the second opening 45 and the first opening 22 remain connected. When the slider 41 moves to the end of the second chute 44 away from the base 1, the piston 3 will drive the slide plate 42 to move on the first chute 23 away from the base 1 through the slider 41, thereby causing the first opening 22 and the second opening 45 to be misaligned to produce a cut-off state. The ammonia in the inflation chamber 21 and the fusion chamber 11 will slowly merge with the coolant under a closed state, so that the ammonia content in the coolant remains uniform. The entire process does not require the use of electrical components for control, and is completely mechanical. The structure is simple and the failure rate is low. The connection between the first opening 22 and the second opening 45 is controlled by the pressure of ammonia. It can automatically close and stop the introduction of ammonia when there is too much ammonia, and can automatically open and continue to introduce ammonia when there is less ammonia, further avoiding the waste of ammonia. It can also automatically balance the ammonia content in the coolant, saving occupied space and production costs, and reducing labor intensity.

[0047] In some embodiments, a baffle is fixedly mounted on the piston 3, and a second opening 45 is provided on the baffle, which is slidably connected to the inflation seat 2 so that the surface of the baffle blocks the first opening 22. When the piston 3 moves to the lowest end near the base 1 as the ammonia is consumed, the second opening 45 coincides with and is connected to the first opening 22, and ammonia continues to enter the inflation chamber 21. When the ammonia introduction rate is greater than the fusion rate, the ammonia content in the inflation chamber 21 will increase, thereby increasing its pressure. The piston 3 will drive the baffle to move away from the base 1, and the second opening 45 and the first opening 22 are offset and cut off. By quickly switching back and forth between connection or offset cutoff between the second opening 45 and the first opening 22, the reaction is more sensitive, further reducing the waste of ammonia, facilitating production, and reducing production costs.

[0048] See also Figures 1-4 In some embodiments, the damping member 43 is a sealing ring, felt or interference fit.

[0049] In this application, the damping member 43 is a sealing ring, felt or interference fit. Among them, an annular groove can be provided on the slide plate 42, and then the damping member 43 such as a sealing ring or felt is placed in the annular groove. The damping member 43 is limited by the annular groove, thereby improving the sealing and connection strength, extending the service life, and further reducing the waste of ammonia.

[0050] When the damping member 43 is a sealing ring, it can improve the sealing between the slide plate 42 and the first slide groove 23, prevent the ammonia in the inflation chamber 21 from leaking out, further reduce the waste of ammonia, and save costs.

[0051] Among them, when the damping member 43 is made of felt, the cost is lower and it is easy to install. The felt can reduce the friction between the slide plate 42 and the first slide groove 23, so that the slider 41 can drive the slide plate 42 to move more effortlessly, further improving the sensitivity.

[0052] The interference fit between the slide plate 42 and the first slide groove 23 produces a certain damping effect, which has lower costs, better sealing performance, and is easy to manufacture.

[0053] See also Figures 1-4 In some embodiments, the inflatable seat 2 includes: a hollow inflatable sleeve 24 and an end cover 25 , one end of the inflatable sleeve 24 is sealed with the base 1 , and the end cover 25 is detachably mounted on the other end of the inflatable sleeve 24 .

[0054] The present application comprises a hollow inflatable sleeve 24 and an end cap 25. One end of the inflatable sleeve 24 is sealed with the base 1, and the end cap 25 is removably mounted on the other end of the inflatable sleeve 24. The hollow inflatable sleeve 24 provides space for ammonia to enter, is simple to manufacture, saves manufacturing costs, and facilitates installation. The end cap 25 can be connected to the inflatable sleeve 24 via a threaded pair or bolted. Opening the end cap 25 facilitates installation of the reset assembly 5 and the inflatable switch 4 within the inflatable sleeve 24, making installation more labor-saving and convenient, and reducing labor intensity.

[0055] See also Figures 1-4 In some embodiments, the reset assembly 5 includes an elastic member 51 installed between the end cover 25 and the piston 3.

[0056] The present application uses an elastic member 51 between the end cover 25 and the piston 3. When the piston 3 drives the slide plate 42 to move to the end away from the base 1 through the slider 41, the elastic member 51 is in its original state. As the ammonia and coolant in the inflation chamber 21 merge, the piston 3 overcomes the elastic force of the elastic member 51 and approaches the base 1, causing the elastic member 51 to be stretched. When the piston 3 drives the slide plate 42 to move to the end of the first slide groove 23 close to the base 1 through the slider 41, the first opening 22 is connected to the second opening 45, and ammonia enters the inflation chamber 21. The elastic member 51 therein also drives the piston 3 to move in the direction away from the base 1 through the elasticity generated. With the assistance of the piston 3, the external ammonia is drawn into the inflation chamber 21, further improving the efficiency of filling the inflation chamber 21 with ammonia, which can further reduce the loss of ammonia, and make the ammonia content in the coolant more uniform and the response more sensitive.

[0057] See also Figures 1-4 In some embodiments, the end cover 25 is mounted on the inflatable sleeve 24 through a threaded pair, and the reset assembly 5 further includes a first limit member 52 and a second limit member 53 rotatably connected to the end cover 25 and the piston 3, respectively. The two ends of the elastic member 51 are respectively mounted on the first limit member 52 and the second limit member 53.

[0058] In the present application, the ends of the elastic member 51 are respectively mounted on the first and second limit members 52, 53, which are respectively connected to the end cap 25 and the piston 3 by rotating them. By rotating the end cap 25, the operator can control the distance between the end cap 25 and the base 1 using a threaded connection. Rotating the first and second limit members 52, 53, which are connected to the end cap 25 and the piston 3, prevents the elastic member 51 from twisting during the rotation process, allowing the operator to rotate the end cap 25 more smoothly. By controlling the distance between the end cap 25 and the base 1, the stretched length of the elastic member 51 can be changed, thereby changing the elastic force exerted by the elastic member 51 on the piston 3. When the elasticity of the elastic member 51 weakens after multiple movements of the piston 3, the operator can rotate the end cap 25 to stretch the elastic member 51 between the piston 3 and the end cap 25, thereby increasing the elastic force of the elastic member 51 on the piston 3, extending its service life, and facilitating adjustment.

[0059] Among them, by changing the distance between the end cover 25 and the piston 3, the pressure change inside the inflation chamber 21 can also be changed, thereby adjusting the fusion rate of ammonia and coolant in the inflation chamber 21, which is suitable for more usage environments and is more flexible to adjust.

[0060] See also Figures 1-4 In some embodiments, the base 1 includes at least one connecting tube 12 and a diffusion chamber 13. The connecting tube 12 is connected to the coolant system pipeline 6 at both ends to receive the coolant and output the coolant after it is combined with the ammonia gas. The diffusion chamber 13 is located between the inlet and outlet of the connecting tube 12 to combine the received ammonia gas with the coolant.

[0061] The present application uses at least one connecting pipe 12 and a diffusion chamber 13. The two ends of the connecting pipe 12 are respectively connected to the coolant system pipeline 6 to connect the coolant and output it after the coolant and ammonia are fused. The diffusion chamber 13 is arranged between the inlet and outlet of the connecting pipe 12 to fuse the connected ammonia with the coolant. The connecting pipe 12 makes it easier for the operator to install the entire ammonia adding device in the coolant system pipeline 6, improves the installation efficiency and the sealing between the base 1, and the diffusion chamber 13 expands the contact area between the ammonia and the passing coolant, so that the passing coolant can quickly and fully fuse with the ammonia, thereby improving the fusion efficiency.

[0062] See also Figures 1-4 In some embodiments, the diameter of the fusion cavity 11 is larger than the diameter of the connecting tube 12. The cross-sectional area of the fusion cavity 11 on the side close to the inflatable seat 2 is larger than the cross-sectional area of the other side away from the inflatable seat 2.

[0063] In this application, by making the diameter of the fusion chamber 11 larger than the diameter of the connecting tube 12, the coolant can expand the area and slow down the flow rate when passing through the fusion chamber 11, so that the ammonia in the inflation chamber 21 and the fusion chamber 11 can be more quickly and fully integrated with the ammonia, further improving the efficiency of integration. The ammonia in the coolant is more uniform.

[0064] The present invention achieves a spontaneous attenuation of the ammonia addition rate by making the cross-sectional area of the fusion chamber 11 closer to the inflation seat 2 larger than the cross-sectional area farther from the inflation seat 2. The physical principle of the gradual decrease in the mass transfer rate at the phase interface during two-phase diffusion is utilized to achieve a spontaneous attenuation of the ammonia addition rate. The conical fusion chamber 11 is designed to increase stability by virtue of a negative feedback mechanism in which the rising coolant liquid level reduces the gas-liquid contact area, thereby improving the stability and uniformity of the fusion of ammonia and coolant.

[0065] See also Figure 1-Figure 5 The present invention also provides a method for passively adding ammonia to a nuclear reactor coolant, comprising the following steps:

[0066] S1. The above-mentioned nuclear reactor coolant passive ammonia adding device is connected to the coolant system pipe 6;

[0067] S2. One end of the inflation tube is connected to the first opening 22, and the other end of the inflation tube is connected to the external ammonia gas;

[0068] S3 automatically fills the ammonia gas into the inflatable chamber 21 through the inflatable tube, and uses the pressure difference to move the piston 3 through the slider 41 to drive the slide 42 to one end away from the base 1 to reach the cut-off state;

[0069] S4. As the ammonia in the inflatable chamber 21 merges with the coolant in the fusion chamber 11, the piston 3 drives the slide plate 42 through the slider 41 to move to one end close to the base 1 to reach the inflated state;

[0070] S5. Repeat the above steps S3 and S4 until all the ammonia in the outside is consumed, and then add ammonia again.

[0071] The present application comprises the following steps: step S1. connecting the above-mentioned passive ammonia adding device for the nuclear reactor coolant to the coolant system pipe 6; step S2. connecting one end of the inflation tube to the first opening 22, and connecting the other end of the inflation tube to the external ammonia; step S3. automatically filling the inflation chamber 21 with ammonia through the inflation tube, and utilizing the pressure difference to cause the piston 3 to drive the slide plate 42 through the slider 41 to move to the end away from the base 1, thereby reaching a cut-off state; step S4. as the ammonia in the inflation chamber 21 merges with the coolant in the fusion chamber 11, utilizing the pressure difference to cause the piston 3 to drive the slide plate 42 through the slider 41 to move to the end close to the base 1, thereby reaching an inflation state; step S5. repeating the above steps S3 and S4 until all the external ammonia is consumed, and then re-adding ammonia. It can make the ammonia content in the coolant more uniform, avoid ammonia waste, control the radiolytic oxygen content in the coolant system pipeline through the self-deceleration ammonia addition strategy, reduce the production of gas products such as hydrogen and nitrogen, and play a certain protective role on the equipment. In addition, the total amount of ammonia consumed during operation is also reduced. The passive design also increases the reliability of the entire ammonia addition process.

[0072] See also Figure 1-Figure 5 In some embodiments, the cut-off state in step S3 is specifically that the ammonia gas filled into the inflation chamber 21 moves the piston 3 toward the end away from the base 1, so that the piston 3 drives the slider 41 to slide in the second slide groove 44 toward the end away from the base 1; until the slider 41 moves to the end of the slide plate 42 away from the base 1, the piston 3 that continues to move drives the second opening 45 on the slide plate 42 to be dislocated with the first opening 22 through the slider 41 and is cut off.

[0073] In the present application, the piston 3 drives the slider 41 to slide in the second slide groove 44 toward the end away from the base 1, so that the piston 3 has a certain stroke to move toward the end away from the base 1, so that more ammonia can be stored in the inflation chamber 21, and there is enough ammonia content to be integrated with the coolant, thereby making the ammonia content in the coolant more uniform and avoiding waste of ammonia.

[0074] See also Figure 1-Figure 5 In some embodiments, the inflation state in step S4 is specifically as follows: as the ammonia in the fusion chamber 11 and the inflation chamber 21 merges with the coolant, the piston 3 moves toward the end close to the base 1, causing the piston 3 to drive the slider 41 to slide in the second slide groove 44 toward the end close to the base 1; until the slider 41 moves to the end of the slide plate 42 close to the base 1, the piston 3 that continues to move drives the second opening 45 on the slide plate 42 to communicate with the first opening 22 through the slider 41, and the external ammonia automatically fills the inflation chamber 21 with ammonia through the inflation tube.

[0075] This application utilizes a passive ammonia dosing device, which slowly moves piston 3 toward base 1 as ammonia content decreases. This device utilizes the physical principle of a continuously decreasing two-phase diffusion rate. Compared to a one-time ammonia dosing strategy, this device also provides pH control to mitigate the corrosive environment. Compared to a continuous ammonia dosing strategy, it produces less gaseous products such as hydrogen and nitrogen. Furthermore, the total amount of ammonia consumed during operation is reduced, and the passive design also increases the reliability of the entire device. The entire process reduces energy loss and conserves resources.

[0076] See also Figure 1-Figure 5 In some embodiments, in the inflated state, when the pressure in the fusion chamber 11 and the inflation chamber 21 and the elastic force of the elastic member 51 are greater than the external pressure, the piston 3 slowly moves away from the base 1 as the ammonia content increases; until the slider 41 moves to the end of the slide plate 42 away from the base 1, causing the second opening 45 on the slide plate 42 to be dislocated and closed from the first opening 22;

[0077] Alternatively, when the pressure in the fusion chamber 11 and the inflation chamber 21 and the elastic force of the elastic member 51 are equal to or less than the external pressure, the piston 3 remains stationary at one end close to the base 1, and the external ammonia gas continuously enters the fusion chamber 11 and the inflation chamber 21 through the connection between the second opening 45 and the first opening 22.

[0078] In the present application, the piston 3 connects the second opening 45 with the first opening 22 or disconnects them in a dislocated manner according to the ammonia content in the charging chamber 21. When there is too much ammonia, the piston 3 automatically closes to stop the flow of ammonia, and when there is too little ammonia, the piston 3 automatically opens to continue the flow of ammonia, further avoiding waste of ammonia and automatically balancing the ammonia content in the coolant. This saves space and production costs, and reduces labor intensity.

[0079] It can be understood that the above embodiments only express the preferred implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the patent scope of the present invention. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present invention, the above technical features can be freely combined, and several deformations and improvements can be made, all of which fall within the scope of protection of the present invention. Therefore, all equivalent changes and modifications made to the scope of the claims of the present invention should fall within the scope of coverage of the claims of the present invention.

Claims

1. A passive ammonia addition device for a nuclear reactor coolant, characterized in that: include: Base (1), inflation seat (2), piston (3), inflation switch (4) and reset assembly (5); The base (1) is provided with a fusion cavity (11) which is connected to a coolant system pipeline (6) and receives a coolant fused with ammonia gas, and the inflation seat (2) is provided on the base (1); The piston (3) is slidably connected to the interior of the inflation seat (2), and the inflation seat (2) and the inflation seat (2) enclose an inflation cavity (21) that is connected to the fusion cavity (11); the inflation seat (2) is provided with a first opening (22); The inflation switch (4) is arranged between the first opening (22) and the inflation cavity (21), and is provided with a second opening (45); The reset assembly (5) is installed between the piston (3) and the inflation seat (2); The ammonia adding device comprises an inflation state and a cut-off state which are switched according to the pressure in the inflation chamber (21); In the inflation state, the first opening (22) is communicated with the second opening (45) to allow ammonia gas from the inflation tube to enter the inflation cavity (21); In the cut-off state, the first opening (22) and the second opening (45) are offset and cut off to isolate the inflation tube from the inflation cavity (21).

2. The passive ammonia addition device for nuclear reactor coolant according to claim 1, characterized in that: The inflation seat (2) is provided with a first slide groove (23), and the inflation switch (4) comprises a slider (41) and a slide plate (42); The slider (41) is fixedly mounted on one side of the piston (3); The slide plate (42) is slidably connected in the first slide groove (23), and a damping member (43) is provided between the slide plate (42) and the first slide groove (23); The slide plate (42) is provided with a second slide groove (44), and the slider (41) is slidably connected in the second slide groove (44); A second opening (45) is provided on the slide plate (42); When the piston (3) moves, the slide block (41) drives the slide plate (42) to move, so that the second opening (45) is connected to the first opening (22) or is disconnected due to displacement.

3. The passive ammonia addition device for nuclear reactor coolant according to claim 2, characterized in that: The damping member (43) is a sealing ring, felt or interference fit.

4. The passive ammonia addition device for nuclear reactor coolant according to claim 2, characterized in that: The inflatable seat (2) comprises: a hollow inflatable sleeve (24) and an end cover (25); one end of the inflatable sleeve (24) is sealedly connected to the base (1); and the end cover (25) is detachably mounted on the other end of the inflatable sleeve (24).

5. The passive ammonia addition device for nuclear reactor coolant according to claim 4, characterized in that: The reset assembly (5) comprises an elastic member (51) installed between the end cover (25) and the piston (3).

6. The passive ammonia addition device for nuclear reactor coolant according to claim 5, characterized in that: The end cover (25) is mounted on the inflation sleeve (24) via a threaded pair. The reset assembly (5) further comprises a first limiting member (52) and a second limiting member (53) which are rotatably connected to the end cover (25) and the piston (3), respectively. Both ends of the elastic member (51) are mounted on the first limiting member (52) and the second limiting member (53), respectively.

7. The passive ammonia addition device for nuclear reactor coolant according to claim 5, characterized in that: The base (1) comprises: at least one connecting pipe (12) and a diffusion chamber (13); both ends of the connecting pipe (12) are respectively connected to the coolant system pipeline (6) to receive the coolant, and output the coolant after the coolant is fused with the ammonia gas; The diffusion chamber (13) is arranged between the inlet and the outlet of the connection pipe (12) to merge the incoming ammonia gas with the coolant.

8. The passive ammonia addition device for nuclear reactor coolant according to claim 7, characterized in that: The diameter of the fusion cavity (11) is larger than the diameter of the connecting tube (12); the cross-sectional area of the fusion cavity (11) on the side close to the inflation seat (2) is larger than the cross-sectional area of the other side away from the inflation seat (2).

9. A method for passively adding ammonia to a nuclear reactor coolant, characterized in that: The steps include: S1. Connecting the passive ammonia adding device for the nuclear reactor coolant according to any one of claims 1 to 8 to the coolant system pipe (6); S2. connecting one end of the inflation tube to the first opening (22), and the other end of the inflation tube to the external ammonia gas; S3. The ammonia gas is automatically filled into the inflation chamber (21) through the inflation tube, and the pressure difference is used to cause the piston (3) to move the slide plate (42) through the slider (41) to the end away from the base (1), thereby reaching the cut-off state; S4. As the ammonia in the inflation chamber (21) fuses with the coolant in the fusion chamber (11), the piston (3) drives the slide plate (42) through the slider (41) to move to one end close to the base (1) by utilizing the pressure difference, thereby reaching an inflation state; S5. Repeat the above steps S3 and S4 until all the ammonia in the outside is consumed, and then add ammonia again; or continue to fill the closed space with ammonia.

10. The method for passive ammonia addition to a nuclear reactor coolant according to claim 9, wherein: The cut-off state in step S3 is specifically that the ammonia gas filled into the inflation chamber (21) moves the piston (3) toward the end away from the base (1), so that the piston (3) drives the slider (41) to slide in the second slide groove (44) toward the end away from the base (1); until the slider (41) moves to the end of the slide plate (42) away from the base (1), the piston (3) that continues to move drives the second opening (45) on the slide plate (42) to be dislocated with the first opening (22) through the slider 41 and cuts off.

11. The method for passive ammonia addition to a nuclear reactor coolant according to claim 10, wherein: The inflation state in step S4 is specifically as follows: as the ammonia in the fusion chamber (11) and the inflation chamber (21) fuses with the coolant, the piston (3) moves toward the end close to the base (1), so that the piston (3) drives the slider (41) to slide in the second slide groove (44) toward the end close to the base (1); until the slider (41) moves to the end of the slide plate (42) close to the base (1), the piston (3) continues to move and drives the second opening (45) on the slide plate (42) to be connected to the first opening (22) through the slider (41), and the external ammonia automatically fills the inflation chamber (21) with ammonia through the inflation tube.

12. The method for passive ammonia addition to a nuclear reactor coolant according to claim 11, wherein: In the inflated state, when the pressure of the fusion chamber (11) and the inflation chamber (21) and the elastic force of the elastic member (51) are greater than the external pressure, the piston (3) slowly moves away from the base (1) as the ammonia content increases; until the slider (41) moves to the end of the slide plate (42) away from the base (1), driving the second opening (45) on the slide plate (42) to be dislocated and cut off from the first opening (22); Alternatively, when the pressure of the fusion chamber (11) and the inflation chamber (21) and the elastic force of the elastic member (51) are equal to or less than the external pressure, the piston (3) remains stationary at one end close to the base (1), and external ammonia gas continuously enters the fusion chamber (11) and the inflation chamber (21) through the connection between the second opening (45) and the first opening (22).

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