A sodium leakage early warning system and method for a sodium-cooled fast reactor secondary circuit

Abstract

The present application relates to the technical field of nuclear reactor safety monitoring, and particularly relates to a sodium leakage early warning system and method for a sodium process room in a secondary loop of a sodium-cooled fast reactor, comprising a ventilation pipeline for conveying a sodium process room aerosol-containing airflow; a pipeline integrated cyclone concentration device connected to the middle section of the ventilation pipeline for enriching and concentrating sodium aerosol in the airflow; and a sodium aerosol detection device connected to the pipeline integrated cyclone concentration device for detecting the concentrated sodium aerosol. The pipeline integrated cyclone concentration device is directly connected to the middle section of the ventilation pipeline, achieving structural integration with the large-volume ventilation system of the secondary loop of the sodium-cooled fast reactor, and being driven by the original fan of the ventilation pipeline without the need for additional power components such as sampling pumps and extraction devices, thereby simplifying the system complexity from the structure, reducing power consumption and failure rate, and solving the problem of external power connection required by the traditional detection device and the difficulty in long-term stable operation of the nuclear island.

Description

Technical Field

[0001] This invention relates to the field of nuclear reactor safety monitoring technology, specifically to an enhanced sodium leakage early warning system and method for the sodium process room in the secondary loop of a sodium-cooled fast reactor. Background Technology

[0002] Sodium-cooled fast reactors are the core reactor type of fourth-generation advanced nuclear energy systems. Using liquid metallic sodium as the reactor coolant, they possess significant advantages such as good neutron economy, strong nuclear fuel breeding capability, and the ability to transpose long-lived, highly radioactive nuclear waste. They hold irreplaceable application prospects in the future large-scale development of nuclear power and the safe disposal of nuclear waste. However, due to the extremely reactive chemical properties of liquid metallic sodium, it readily undergoes violent oxidation and combustion upon contact with air and moisture at high temperatures, leading to sodium fire accidents. Therefore, early, accurate, and comprehensive monitoring of sodium leaks is a crucial technology for ensuring the safe and stable operation of sodium-cooled fast reactors, directly impacting reactor structural integrity, radioactive containment safety, and the safety of personnel and equipment.

[0003] The secondary loop system of a sodium-cooled fast reactor mainly includes key equipment such as a steam generator, sodium pumps, sodium delivery pipelines, and sodium storage containers, all housed within a closed sodium process room. To ensure environmental safety, control the spread of radioactive materials, and maintain a negative pressure environment within the process room, the secondary loop sodium process room is typically equipped with a high-volume ventilation system characterized by high airflow velocity, large space volume, and rapid gas replacement. Under high temperature, high pressure, and long-term operating conditions, there is a risk of minor damage and trace sodium leakage at locations such as sodium pipeline welds, valve sealing surfaces, and equipment interfaces. In the initial stages of leakage, sodium often diffuses as micro- and nano-sized sodium aerosols with the ventilation airflow, making it difficult to form visible liquid sodium drips or flows, and traditional monitoring methods are insufficient for effective detection.

[0004] The most widely used leak monitoring device in current sodium-cooled fast reactor engineering is the distributed sodium leak detector. This type of detector uses two parallel stainless steel wires as its core sensing elements, relying on the conductivity of liquid sodium to trigger a short-circuit alarm. When liquid sodium drips directly and bridges the two stainless steel wires, the detector outputs a switching signal to the distributed control system, triggering an alarm and interlocking protection action. However, this technology has significant drawbacks: it can only achieve point-to-point, contact-based monitoring, failing to cover large spaces and high-volume ventilation areas; it is completely unresponsive to leaks that do not directly drip onto the detector surface; and it lacks the ability to identify minute early leaks spreading in aerosol form, making it difficult to meet the requirements for ultra-early warning.

[0005] Among existing publicly available technologies, there are sodium aerosol detection systems based on spectral principles. For example, patent document CN218766496U, entitled "A Sodium Aerosol Detection System in Open Air," discloses a technical solution for directly detecting sodium aerosols in open air. This system utilizes an electrical energy conversion unit and a pulse generation unit to generate a high-repetition-rate, high-voltage nanosecond pulse, which produces a spark discharge within a discharge device in open air, thereby ionizing and exciting sodium aerosols. The system then collects sodium characteristic spectral lines through an optical fiber collimator and a spectrometer. Simultaneously, a pulse discharge and spectrometer time synchronization unit is incorporated to improve the signal-to-noise ratio. This technology overcomes, to some extent, the limitations of traditional contact-based detection. However, it still has obvious limitations: it adopts a single-point passive sampling or local active sampling method, which has a limited sampling coverage and is difficult to adapt to the high air volume, large space and strong airflow disturbance conditions in the secondary loop sodium process room; the sampled gas is not efficiently enriched, and the trace aerosol signal is diluted by a large amount of air, resulting in a high detection limit and slow response speed, making it impossible to capture weak leakage signals; the system is not integrated with the ventilation duct, and additional sampling pumps, power components and complex pipelines are required, resulting in structural redundancy and insufficient reliability, making it difficult to meet the long-term online operation requirements in the harsh environment of the nuclear island.

[0006] In addition, existing aerosol concentration and separation devices mostly adopt conventional cyclone separation structures, which have obvious technical shortcomings: high escape rate of fine particles and low capture efficiency of 0.1–1μm micro-nano sodium aerosols; stable central vortex cores are easily formed in the overflow pipe area, causing short-circuit flow to directly carry particles away, making it difficult to improve the concentration factor; they cannot be integrated with the nuclear island ventilation duct, require external power and occupy additional space, and are not suitable for direct application in the high-volume process room of the secondary loop of sodium-cooled fast reactors.

[0007] In summary, existing sodium leakage monitoring technologies generally suffer from prominent problems such as large monitoring blind spots, insufficient sensitivity, delayed response, incompatibility with high-volume ventilation systems, and difficulty in achieving ultra-early warnings. They cannot meet the requirements of high reliability, high sensitivity, full coverage, and no blind spots for sodium leakage safety monitoring in the sodium process room of the secondary loop of sodium-cooled fast reactors.

[0008] Therefore, developing an enhanced sodium leakage early warning system that is integrated with ventilation ducts, requires no additional power, has high concentration, and responds quickly is of significant engineering value and practical necessity for improving the operational safety of the secondary loop of sodium-cooled fast reactors. Summary of the Invention

[0009] The purpose of this invention is to provide an enhanced sodium leakage early warning system and method for the sodium process room in the secondary loop of a sodium-cooled fast reactor in order to solve the above-mentioned problems. By directly connecting the integrated cyclone enrichment device in the middle section of the ventilation duct, the system is structurally integrated with the high-volume ventilation system of the secondary loop of the sodium-cooled fast reactor. Driven by the original fan in the ventilation duct, there is no need to add additional power components such as sampling pumps and extraction devices. This simplifies the system complexity, reduces power consumption and failure rate, and solves the problem that traditional detection devices require external power and are difficult to operate stably in the nuclear island for a long time. Details are described below.

[0010] To achieve the above objectives, the present invention provides the following technical solution: This invention provides an enhanced sodium leakage early warning system for the sodium process inter-loop of a sodium-cooled fast reactor, comprising: Ventilation ducts are used to transport aerosol-containing airflow between sodium processing areas; An integrated cyclone concentrator is connected to the middle section of the ventilation duct and is used to enrich and concentrate sodium aerosols in the airflow. A sodium aerosol detection device is connected to the integrated pipeline cyclone concentrator and is used to detect the concentrated sodium aerosol. The integrated cyclone concentrator in the pipeline can utilize the existing power of the ventilation duct to concentrate aerosols and supply gas to the sodium aerosol detection device, thereby enabling sodium aerosol leakage concentration and detection.

[0011] Preferably, the integrated pipeline cyclone concentrator is a cyclone amplification device, which has several sets of cyclone devices built in.

[0012] Preferably, the plurality of cyclone devices are arranged in series to progressively increase the aerosol concentration factor and particle capture efficiency.

[0013] Preferably, the plurality of cyclone devices are arranged in parallel to improve airflow and processing capacity, and to adapt to high ventilation conditions.

[0014] Preferably, the cyclone device includes a swirl cone section and an overflow port and a concentration hopper connected to the upper and lower ports of the swirl cone section. An inlet is connected to the outside of the swirl cone section, and a short-circuit flow suppression cavity is formed inside the inlet for enriching micro- and nano-sized sodium aerosols.

[0015] Preferably, the sodium aerosol detection device and the integrated pipeline cyclone concentrator are connected by a concentrated gas sampling pipeline and a concentrator return pipeline to form a circulation loop.

[0016] Preferably, the air inlet of the integrated cyclone concentrator is connected to an air inlet pipe, and the air outlet is connected to a purified air pipe. Both the air inlet pipe and the purified air pipe are connected to a ventilation duct.

[0017] Preferably, the sodium aerosol detection device is a microwave plasma spectroscopy detection unit.

[0018] This invention also discloses an enhanced sodium leakage early warning method between sodium processes in the secondary loop of a sodium-cooled fast reactor, comprising the following steps: S1. The sodium-containing aerosol airflow is sent into the integrated cyclone concentrator through the ventilation duct, and the aerosol is enriched and concentrated by the original power of the ventilation duct. S2. The concentrated sodium aerosol is sent to a sodium aerosol detection device for high-sensitivity detection.

[0019] Preferably, the concentrated aerosol enters the detection device through the sampling pipe, and the gas after detection returns to the concentration device through the return pipe to form a circulation loop. The concentrated and purified gas is discharged to the downstream of the ventilation duct through the purification gas pipe.

[0020] The beneficial effects are as follows: 1. By directly connecting the integrated cyclone enrichment device to the middle section of the ventilation duct, the present invention achieves structural integration with the large-volume ventilation system of the secondary loop of the sodium-cooled fast reactor. Driven by the original fan in the ventilation duct, there is no need to add additional power components such as sampling pumps and extraction devices. The structure simplifies the system complexity, reduces power consumption and failure rate, and solves the problem that traditional detection devices require external power and are difficult to operate stably in the nuclear island for a long time.

[0021] 2. This application uses a hydrocyclone amplification device with multiple built-in cyclone devices, which can be arranged in series or in parallel according to the working conditions. The series arrangement can gradually increase the aerosol concentration factor and particle capture efficiency, and lower the detection limit; the parallel arrangement can improve the airflow and processing capacity, and adapt to the working conditions of large ventilation volume, thus solving the problem that the existing technology cannot match the ventilation environment of high flow rate and high velocity process rooms.

[0022] 3. This application forms a closed loop by connecting the concentrated gas sampling pipeline and the concentrator return pipeline, so that the concentrated sodium aerosol is stably delivered to the sodium aerosol detection device. After the detection is completed, the gas can be returned to the concentration system for reuse, which avoids sample loss, improves detection stability and repeatability, prevents leakage of gas, and enhances the environmental safety of the nuclear island.

[0023] 4. This application uses a microwave plasma spectroscopy detection unit as a sodium aerosol detection device. Combined with a front-end high-concentration structure, it can quickly identify sodium characteristic spectral signals. Compared with the currently disclosed open space direct detection method, it has higher detection sensitivity and shorter response time, and can achieve sensitive early warning of sodium leakage.

[0024] 5. This application connects the air inlet pipe and the purified air pipe directly to the ventilation duct, realizing the connection between the entire process of sampling, concentration, detection, and exhaust and the ventilation system of the process room. The monitoring range covers the entire ventilation duct and process room, with no monitoring dead spots or detection blind spots, overcoming the shortcomings of distributed sodium leak detectors that can only detect at a single point and in a small area and are prone to missed detection. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a system piping connection diagram of the present invention; Figure 2 This is a front view structural diagram of the cyclone device of the present invention; Figure 3 This is a three-dimensional structural schematic diagram of the cyclone device of the present invention; Figure 4 This is a left-side structural view of the cyclone device of the present invention; Figure 5 This is the present invention. Figure 4 A cross-sectional view of the structure at point AA; Figure 6 This is a graph showing the change in sodium aerosol detection concentration over time for Group 1 of this invention; Figure 7 This is a graph showing the change in sodium aerosol detection concentration over time for Group 2 of this invention; Figure 8 This is a graph showing the change in sodium aerosol detection concentration over time for Group 3 of this invention; Figure 9 This is a graph showing the change in sodium aerosol detection concentration over time for Group 4 of this invention.

[0027] The annotations in the attached figures are explained as follows: 1. Ventilation duct; 2. Integrated cyclone concentrator; 201. Cyclone device; 201a. Sample inlet; 201b. Cyclone cone section; 201c. Concentrator hopper; 201d. Overflow port; 201e. Short-circuit flow suppression chamber; 202. Air inlet pipe; 203. Purified gas pipe; 3. Sodium aerosol detection device; 4. Concentrated gas sampling pipe; 5. Concentrator return pipe. Detailed Implementation

[0028] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0029] It should be noted that all directional and positional terms used in this invention, such as "up," "down," "left," "right," "front," "back," "vertical," "horizontal," "inner," "outer," "top," "lower," "lateral," "longitudinal," and "center," are only used to explain the relative positional relationships and connections between components in a specific state (as shown in the accompanying drawings). They are merely for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. Furthermore, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated.

[0030] In the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0031] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0032] See Figures 1-9 As shown, this invention provides an enhanced sodium leakage early warning system between the sodium processes in the secondary loop of a sodium-cooled fast reactor, comprising: Ventilation duct 1 is used to transport aerosol-containing airflow in the sodium process room, thereby realizing full-area airflow collection under large space and large air volume conditions, covering the entire monitoring area of ​​the sodium process room, and eliminating the monitoring blind spots existing in traditional single-point detection. The integrated cyclone concentrator 2 is connected to the middle section of the ventilation duct 1 and is used to enrich and concentrate sodium aerosols in the airflow. This allows for the efficient aggregation of trace amounts and low concentrations of micro-nano-scale sodium aerosols, significantly increasing the concentration of the sample to be tested and providing a prerequisite for subsequent high-sensitivity detection. The sodium aerosol detection device 3 is connected to the pipeline integrated cyclone concentrator 2 and is used to detect the concentrated sodium aerosol in order to quickly identify the characteristic spectral signal of sodium and realize the accurate judgment and ultra-early warning of trace leaks. The integrated cyclone concentrator 2 can utilize the existing power of the ventilation duct 1 to achieve aerosol concentration and supply gas to the sodium aerosol detection device 3, thereby realizing sodium aerosol leakage concentration detection. This ensures that the system does not require an additional power source, has a simplified structure, and operates reliably, meeting the stringent requirements of long-term online monitoring in the nuclear island.

[0033] As an optional implementation, the pipeline integrated cyclone concentrator 2 is a cyclone amplification device. The cyclone amplification device has several sets of cyclone devices 201 built in. With this configuration, the aerosol concentration effect and particle capture capability can be significantly improved through the synergistic effect of the multi-stage separation structure, breaking through the bottleneck of insufficient efficiency of traditional single-stage cyclone separation. Several sets of cyclone devices 201 are arranged in series to progressively increase the aerosol concentration factor and particle capture efficiency. This arrangement can achieve a step-by-step amplification of the concentration factor, progressive enrichment of trace leaks, and further reduce the escape rate of micro and nano particles, thereby improving the detection limit. Several sets of cyclone devices 201 are arranged in parallel to improve airflow and processing capacity, and to adapt to high ventilation conditions. This arrangement can meet the demand for high ventilation and ensure that the concentration and separation effect is stable and efficient even under high flow rate. The cyclone device 201 includes a cyclone cone section 201b and an overflow port 201d and a concentration hopper 201c connected to the upper and lower ports of the cyclone cone section 201b. The overflow port 201d is used to discharge the purified gas flow, and the concentration hopper 201c is used to collect the enriched high-concentration sodium aerosol. The outside of the cyclone cone section 201b is connected to the sample inlet 201a. A short-circuit flow suppression cavity 201e is formed in the sample inlet 201a, which is used to enrich micro- and nano-sized sodium aerosols and collect dust. By collecting dust in the gas sample, dust is prevented from entering the spectrometer and affecting the instrument's operation. Specifically, this setting facilitates the destruction of the central vortex nucleus near the overflow pipe, blocks the direct escape of particles carried by the short-circuit flow, and forces the fine particles to re-participate in centrifugal separation. The sodium aerosol detection device 3 and the integrated cyclone concentrator 2 are connected by a concentrated gas sampling pipe 4 and a concentrator return pipe 5, forming a circulation loop. In this way, the gas after detection can be returned to the system for recycling, avoiding loss of concentrated sample, improving detection stability and signal repeatability, and preventing leakage of gas.

[0034] The integrated cyclone concentrator 2 is connected to the air inlet pipe 202 at the air inlet end and to the purified air pipe 203 at the air outlet end. Both the air inlet pipe 202 and the purified air pipe 203 are connected to the ventilation duct 1, thereby achieving seamless connection between the entire process of sampling, concentration and exhaust and the ventilation duct 1 without damaging the original ventilation system structure and negative pressure state.

[0035] The sodium aerosol detection device 3 is a microwave plasma spectroscopy detection unit. This configuration enables efficient excitation and ionization of sodium aerosols without a carrier gas. Combined with high-magnification concentration at the front end, the sensitivity is much higher than direct detection in open spaces, with faster response and stronger anti-interference.

[0036] An enhanced sodium leakage early warning method for the secondary loop sodium process in a sodium-cooled fast reactor includes the following steps: S1. The sodium-containing aerosol airflow is sent into the integrated cyclone concentrator 2 through the ventilation duct 1. The aerosol is enriched and concentrated using the original power of the ventilation duct 1. Specifically, the airflow is driven into the cyclone concentrator by the ventilation fan. The sodium aerosol is highly enriched by short-circuit flow suppression and centrifugal separation without the need for an additional sampling pump. S2. The concentrated sodium aerosol is sent to the sodium aerosol detection device 3 for high-sensitivity detection. Specifically, the characteristic sodium spectrum is generated by microwave plasma excitation to quickly determine whether there is a trace amount of sodium leakage and achieve ultra-early warning.

[0037] The concentrated aerosol enters the detection device through the sampling pipe. After detection, the gas returns to the concentration device through the return pipe, forming a circulation loop. The concentrated and purified gas is discharged to the downstream of the ventilation pipe 1 through the purification gas pipe 203. This ensures that the detection process is continuous and stable, and that there is no waste of samples. At the same time, it maintains the airflow balance of the ventilation system and the negative pressure safety between processes, achieving blind spot-free, highly reliable, and ultra-early sodium leakage warning.

[0038] By directly connecting the integrated cyclone enrichment device 2 to the middle section of the ventilation duct 1, structural integration with the high-volume ventilation system of the second loop of the sodium-cooled fast reactor is achieved. Driven by the original fan of the ventilation duct 1, there is no need to add additional power components such as sampling pumps and extraction devices. This simplifies the system complexity, reduces power consumption and failure rate, and solves the problem that traditional detection devices require external power and are difficult to operate stably in the nuclear island for a long time.

[0039] The aerosol amplification equipment incorporates multiple cyclone devices 201, which can be arranged in series or parallel depending on the operating conditions. The series arrangement can progressively increase the aerosol concentration factor and particle capture efficiency, and lower the detection limit. The parallel arrangement can improve the airflow and processing capacity, and is suitable for high ventilation conditions, solving the problem that existing technologies cannot match the ventilation environment of high flow rate and high velocity process rooms.

[0040] By forming a closed loop through the concentrated gas sampling pipeline 4 and the concentrator return pipeline 5, the concentrated sodium aerosol is stably delivered to the sodium aerosol detection device 3. After the detection is completed, the gas can be returned to the concentration system for reuse, which avoids sample loss, improves detection stability and repeatability, prevents leaked gas from overflowing, and enhances the environmental safety of the nuclear island.

[0041] The microwave plasma spectroscopy detection unit is used as the sodium aerosol detection device 3. Combined with the front-end high-magnification concentration structure, it can quickly identify sodium characteristic spectral signals. Compared with the currently disclosed open space direct detection method, it has higher detection sensitivity and shorter response time, and can realize sensitive early warning of sodium leakage.

[0042] By directly connecting the air inlet pipe 202 and the purified air pipe 203 to the ventilation duct 1, the entire process of sampling, concentration, detection, and exhaust is connected to the ventilation system of the process room. The monitoring range covers the entire ventilation duct 1 and the process room, with no monitoring dead spots or blind spots, overcoming the shortcomings of distributed sodium leak detectors that can only detect at a single point and in a small area and are prone to missed detection.

[0043] To verify the technical effectiveness of the short-circuit flow-controlled negative pressure cyclone aerosol concentrator of this invention, four sets of comparative experiments were conducted using the device of this invention and conventional unenhanced spectral detection under the same detection environment, same gas source concentration, same sampling flow rate, and same negative pressure dynamic conditions. The experimental object was micro-nano-scale sodium aerosol generated by a simulated leak in a sodium-cooled fast reactor. The experimental system included an aerosol generating device, a sampling pipeline, the concentrator of this invention, a conventional negative pressure cyclone separator, a microwave plasma spectral detection unit, and a data acquisition system.

[0044] I. Experimental Conditions Experimental medium: sodium-cooled fast reactor simulating leaked sodium aerosol Sampling flow rate: kept constant throughout. System power: negative pressure drive, fan load is the same. Detection target: 0.1-1μm micro / nano sodium aerosol Environmental conditions: Temperature, humidity, and ventilation conditions should be kept consistent with those of the reactor process. Comparison objects: Experimental group: Short-circuit flow controlled negative pressure cyclone aerosol concentration device of the present invention Control group: Traditional negative pressure cyclones without annular microchannels, short-circuit flow suppression cavities, or short-circuit flow control structures. II. Comparative experimental data are as follows

[0045] III. Explanation of Experimental Results Group 1 (see Figure 6Under high-concentration leakage conditions, the device of this invention can quickly trigger an alarm in 102.5 seconds, with a peak concentration as high as 15994.1 ppb, and can continuously and stably detect for 10 minutes; conventional spectral detection has no concentration signal and no alarm throughout the entire process.

[0046] Group 2 (see Figure 7 Under medium-concentration leakage conditions, the device of this invention can alarm within 600 seconds, with a peak concentration of 2128.7 ppb, and can continuously detect for up to 85 minutes; conventional spectral detection still shows no response.

[0047] Group 3 (see Figure 8 Under low-concentration leakage conditions, the device of this invention can still detect leaks stably for 2580s, achieving early warning of trace leaks; conventional spectral detection cannot capture low-concentration aerosols at all, and there is no detection data.

[0048] Group 4 (see Figure 9 Under optimal response conditions, the device of this invention has a response time of 72.5s, which can achieve ultra-early warning of sodium leakage; conventional spectral detection still has no response.

[0049] IV. Experimental Conclusions This invention solves the short-circuit escape problem of traditional hydrocyclones by using a short-circuit flow suppression cavity and an annular microchannel structure, achieving a capture efficiency of ≥95% for micro- and nano-sized sodium aerosols and a concentration factor of ≥1000 times.

[0050] Under high, medium, and low concentration leakage simulations, the device of this invention can output detection signals quickly, stably, and accurately, while conventional spectral detection has no response, no alarm, and no detection data throughout the entire process. Therefore, this invention can realize ultra-early, highly sensitive, and blind-zone-free online monitoring of trace sodium leakage in sodium-cooled fast reactors, meeting the safety early warning requirements of the nuclear industry.

[0051] This invention solves the short-circuit escape problem by setting a coaxial annular microchannel in the straight section of the hydrocyclone and dividing the internal flow field into an external swirling cavity and a central short-circuit flow suppression cavity. The vertical direct exhaust flow destroys the quasi-rigid central vortex core of the traditional hydrocyclone, blocking the path of fine particles to escape directly along the overflow pipe. This forces the escaped particles to return to the swirling cavity to re-participate in centrifugal separation, which can reduce the escape rate of micro and nano particles from more than 10% to less than 2%.

[0052] As a physical separation structure, the annular microchannel forcibly separates the outer swirling flow field from the central straight flow field, avoiding the mixing and disturbance of the two airflows. This makes the swirling flow field more stable and the pressure fluctuation smaller. It can maintain stable separation efficiency under negative pressure drive, flow fluctuation and long-term continuous operation conditions, without clogging or attenuation, and is suitable for the long-term online monitoring requirements of nuclear industry sites.

[0053] Using negative pressure as the separation power, the blower is placed at the outlet end of the overflow pipe, so that the gas containing aerosols is first separated and concentrated by cyclone separation, and then the clean gas comes into contact with the blower. This changes the harm of direct contact between the blower and unseparated aerosols in the traditional positive pressure sampling, avoids the wear, corrosion and adhesion of sodium aerosol particles to the blower blades and cavity, eliminates the safety hazards of particle accumulation, blockage, heat generation and even combustion and explosion, and improves the safety of on-site operation in the nuclear industry.

[0054] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An enhanced sodium leakage early warning system for the sodium process inter-loop of a sodium-cooled fast reactor, characterized in that, include: Ventilation duct (1) is used to transport aerosol-containing airflow in the sodium process room; The integrated cyclone concentrator (2) is connected to the middle section of the ventilation duct (1) and is used to enrich and concentrate sodium aerosol in the airflow. The sodium aerosol detection device (3) is connected to the integrated pipeline cyclone concentrator (2) and is used to detect the concentrated sodium aerosol. The integrated cyclone concentrator (2) can utilize the existing power of the ventilation duct (1) to achieve aerosol concentration and supply gas to the sodium aerosol detection device (3), thereby realizing sodium aerosol leakage concentration detection.

2. The enhanced sodium leakage early warning system for the sodium process inter-loop of the sodium-cooled fast reactor according to claim 1, characterized in that, The integrated pipeline cyclone concentrator (2) is a cyclone amplification device, and the cyclone amplification device has several sets of cyclone devices (201) built in.

3. The enhanced sodium leakage early warning system for the sodium process inter-loop of the sodium-cooled fast reactor according to claim 2, characterized in that, The several sets of cyclone devices (201) are arranged in series to progressively increase the aerosol concentration factor and particle capture efficiency.

4. The enhanced sodium leakage early warning system for the sodium process inter-loop of the sodium-cooled fast reactor according to claim 2, characterized in that, The aforementioned cyclone devices (201) are arranged in parallel to improve airflow and processing capacity, and are suitable for high ventilation conditions.

5. The enhanced sodium leakage early warning system for the sodium process inter-loop of the sodium-cooled fast reactor according to claim 2, characterized in that, The cyclone device (201) includes a swirl cone section (201b) and an overflow port (201d) and a concentration hopper (201c) connected to the upper and lower ports of the swirl cone section (201b). An inlet port (201a) is connected to the outside of the swirl cone section (201b). A short-circuit flow suppression cavity (201e) is formed inside the inlet port (201a) for enriching micro- and nano-sized sodium aerosols.

6. The enhanced sodium leakage early warning system for the sodium process inter-loop of the sodium-cooled fast reactor according to claim 1, characterized in that, The sodium aerosol detection device (3) and the integrated pipeline cyclone concentrator (2) are connected by a concentrated gas sampling pipeline (4) and a concentrator return pipeline (5), forming a circulation loop.

7. The enhanced sodium leakage early warning system for the sodium process inter-loop of the sodium-cooled fast reactor according to claim 1, characterized in that, The integrated cyclone concentrator (2) has an air inlet end connected to an air inlet pipe (202) and an air outlet end connected to a purified air pipe (203). Both the air inlet pipe (202) and the purified air pipe (203) are connected to a ventilation duct (1).

8. The enhanced sodium leakage early warning system for the sodium process inter-loop of the sodium-cooled fast reactor according to claim 1, characterized in that, The sodium aerosol detection device (3) is a microwave plasma spectroscopy detection unit.

9. A method for enhanced sodium leakage early warning between sodium processes in the secondary loop of a sodium-cooled fast reactor, characterized in that, Includes the following steps: S1. The sodium-containing aerosol airflow is sent into the integrated cyclone concentrator (2) through the ventilation duct (1) to enrich and concentrate the aerosol using the original power of the ventilation duct (1). S2. The concentrated sodium aerosol is sent to the sodium aerosol detection device (3) for high-sensitivity detection.

10. The enhanced sodium leakage early warning method between the sodium processes in the secondary loop of a sodium-cooled fast reactor according to claim 9, characterized in that, The concentrated aerosol enters the detection device through the sampling pipe. After detection, the gas returns to the concentration device through the return pipe, forming a circulation loop. The concentrated and purified gas is discharged downstream of the ventilation pipe (1) through the purification gas pipe (203).

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