Test device and method for general erosion corrosion in fast reactor coolant environment

Abstract

The application discloses a kind of test device and method for general erosion corrosion in fast reactor coolant environment, it is related to nuclear power material testing technical field, including corrosion kettle, heating device, stirring device and object table, heating device is used to heat corrosion kettle, stirring device includes rotary drive device and stirring assembly, the fixed end of rotary drive device is fixedly arranged on corrosion kettle, the driving end of rotary drive device is fixedly connected with stirring assembly, stirring assembly is inserted into corrosion kettle, for stirring the cooling medium in corrosion kettle, object table is arranged in corrosion kettle for carrying corrosion sample, gas inlet is provided on corrosion kettle, gas inlet is used to pass into hydrogen gas or oxygen gas mixture, to adjust the oxygen concentration in corrosion kettle.The application can truly reproduce the environment of flow medium erosion, corrosion deterioration and oxygen concentration synergistic effect under actual working condition.

Description

Technical Field

[0001] This invention relates to the field of nuclear power material testing technology, and in particular to a test apparatus and method for general erosion corrosion in fast reactor coolant environments. Background Technology

[0002] Lead-cooled fast reactors, sodium-cooled fast reactors, molten salt reactors, and supercritical water-cooled reactors are important candidate reactor types due to their high intrinsic safety, long service life, compact structure, and high power density, as well as their nuclear waste transmutation capability, making them promising candidates for application. However, the engineering application of these reactor types is generally limited by the environmental compatibility issues between structural materials and high-temperature coolants. In high-temperature dynamic coolant environments (such as liquid lead-bismuth, liquid sodium, liquid molten salt, and high-temperature critical water), structural materials are prone to corrosion, mass migration, and environmental embrittlement, leading to significant deterioration of material fatigue performance and promoting the initiation and propagation of corrosion fatigue cracks. When cracks penetrate the wall thickness of pressure-bearing components, they may cause media leakage or even instantaneous failure, seriously threatening the safety and economy of system operation.

[0003] In all the aforementioned coolant environments, oxygen concentration plays a crucial role: in liquid lead-bismuth and liquid sodium, precise control of oxygen concentration can form a protective oxide film on the material surface, inhibiting further corrosion; in liquid molten salt, oxygen concentration affects the redox potential of the molten salt, thus determining the corrosion rate; in high-temperature critical water, dissolved oxygen concentration is directly related to the oxidation behavior and stress corrosion cracking susceptibility of the material. Therefore, precise regulation and monitoring of oxygen concentration is a core common technology for achieving environmental compatibility control of coolants in fourth-generation fast reactors.

[0004] Under actual operating conditions, the internal medium of a Generation IV fast reactor is a continuously flowing high-temperature coolant (liquid lead-bismuth, liquid sodium, liquid molten salt, or high-temperature critical water). Existing corrosion or fatigue testing equipment for these environments is primarily based on static medium conditions, making it difficult to reflect the material service behavior under the coupled effects of flowing media and mechanical loads, thus failing to meet engineering application requirements. Therefore, there is an urgent need for a universal erosion corrosion testing device and method for fast reactor coolant environments to solve the aforementioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide a universal erosion corrosion test apparatus and method for fast reactor coolant environments, in order to solve the problems existing in the prior art and to realistically reproduce the environment of erosion, corrosion degradation and oxygen concentration synergistic effect of flowing media under actual working conditions.

[0006] To achieve the above objectives, the present invention provides the following solution: This invention provides a universal erosion corrosion testing apparatus for fast reactor coolant environments, comprising a corrosion vessel, a heating device, a stirring device, and a stage. The heating device heats the corrosion vessel. The stirring device includes a rotary drive and a stirring assembly. The fixed end of the rotary drive is fixedly mounted on the corrosion vessel, and the driving end is fixedly connected to the stirring assembly. The stirring assembly extends into the corrosion vessel to stir the cooling medium within it. The stage is positioned inside the corrosion vessel to hold the corrosion sample. A gas inlet is provided on the corrosion vessel for introducing a mixed hydrogen gas or a mixed oxygen gas to adjust the oxygen concentration within the corrosion vessel.

[0007] In some embodiments, the corrosion vessel includes a vessel body and a vessel lid, the vessel lid being disposed on top of the vessel body and capable of forming a sealed connection.

[0008] In some embodiments, a support frame is also included, wherein multiple support frames are arranged around the circumference of the vessel body, the top of the support frame is fixedly connected to the vessel body, and the bottom of the support frame is fixedly connected to the ground.

[0009] In some embodiments, the stage includes a fixed shaft and a stage body, the fixed shaft is fixedly connected to the vessel lid, the stage body is detachably connected to the fixed shaft, and a thermocouple is provided near the stage body.

[0010] In some embodiments, multiple platforms are provided inside the corrosion vessel, and all platforms are at the same distance from the stirring assembly.

[0011] In some embodiments, the stirring assembly includes a stirring shaft and stirring blades, the stirring blades being hinged to the stirring shaft and capable of being locked by a locking device.

[0012] In some embodiments, the heating device is a high-temperature furnace, and the vessel is disposed inside the high-temperature furnace.

[0013] In some embodiments, the inner wall of the vessel is coated with an alumina ceramic liner with a thickness of not less than 15 micrometers.

[0014] In some embodiments, an oxygen concentration monitoring device is also included, which is fixedly mounted on the vessel body and has a probe extending into the vessel body.

[0015] The present invention also provides a test method for general erosion corrosion in a fast reactor coolant environment, which is implemented using the test apparatus for general erosion corrosion in a fast reactor coolant environment as described above, and includes the following steps: Step 1: Heat the corrosion vessel to the target temperature using a heating device, and control the oxygen concentration to the target value; Step 2: Stop the gas supply and reduce the temperature of the corrosion vessel to the set value; Step 3: Load the corrosion sample onto the stage and install the stage into the corrosion vessel; Step 4: Reheat the corrosion vessel using a heating device, introduce gas through the gas inlet to adjust the oxygen concentration, and turn on the stirring device; Step 5: Start timing when the oxygen concentration reaches the target value, and end the test when the target time is reached; Step 6: Stop the gas flow through the gas inlet, cool the corrosion vessel to the set value, and remove the corrosion sample from the stage.

[0016] The present invention achieves the following technical effects compared to the prior art: The universal erosion corrosion test apparatus provided by this invention for fast reactor coolant environments employs a rotary drive device to move a stirring assembly within the corrosion vessel, creating a controllable and stable coolant flow field. This apparatus can simulate the high-speed flow and erosion environment of four generations of fast reactor coolants: liquid lead-bismuth, liquid sodium, liquid molten salt, and high-temperature critical water. It overcomes the limitations of traditional test apparatuses that can only conduct static immersion corrosion, realistically reproducing the erosion-corrosion coupling effect between the flowing medium and the material surface. The obtained data on material corrosion rate, film growth patterns, and fatigue degradation characteristics are more consistent with the actual service conditions of the reactor, providing reliable support for fast reactor structural material selection, life prediction, and safety evaluation. A dedicated gas inlet is provided on the corrosion vessel, allowing for flexible introduction of mixed hydrogen or oxygen gases to regulate the oxygen concentration within the vessel and stably maintain it within the target range. For liquid lead-bismuth / sodium, the protective oxide film formation conditions can be adjusted; for molten salt, the redox potential can be precisely controlled; and for high-temperature critical water, the dissolved oxygen level can be stabilized. One apparatus is compatible with the oxygen control requirements of multiple fast reactor coolants.

[0017] This device is a universal erosion corrosion testing platform, simultaneously adaptable to four mainstream fourth-generation fast reactor coolant environments: liquid lead-bismuth, liquid sodium, liquid molten salt, and high-temperature critical water. It eliminates the need for separately designed equipment for different media, significantly reducing the cost of platform construction and space requirements. The device features a modular structure and standardized interfaces, facilitating sample replacement, media switching, and component maintenance. It can meet the batch testing needs of universities, research institutes, and nuclear power companies for the corrosion performance of materials under multiple systems and operating conditions, offering multi-functionality and significantly improving testing efficiency and economy. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments 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.

[0019] Figure 1 This is a schematic diagram of the structure of a test apparatus for general erosion corrosion in a fast reactor coolant environment, as shown in some embodiments of the present invention. Figure 2 This is a simplified diagram of the oxygen-controlled gas circuit in some embodiments of the present invention; Figure 3 This is a flowchart of a test method for general erosion corrosion in a fast reactor coolant environment, as described in some embodiments of the present invention.

[0020] In the diagram: 1-Corrosion vessel; 101-Vessel body; 102-Vessel cover; 2-Heating device; 3-Stirring device; 31-Rotary drive device; 32-Stirring shaft; 33-Stirring blades; 4-Support frame; 5-Platform; 51-Fixed shaft; 52-Platform body; 6-Gas inlet; 7-Waste gas outlet; 8-Oxygen concentration monitoring device; 9-Mixed hydrogen and mixed oxygen cylinders; 10-Stop valve; 11-Gas mass flow meter; 12-Check valve; 13-Pressure gauge; 14-Digital multimeter; 15-Control host. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] The purpose of this invention is to provide a universal erosion corrosion test apparatus and method for fast reactor coolant environments, in order to solve the problems existing in the prior art and to realistically reproduce the environment of erosion, corrosion degradation and oxygen concentration synergistic effect of flowing media under actual working conditions.

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Example 1 like Figures 1-3As shown, the present invention provides a test apparatus for general erosion corrosion in a fast reactor coolant environment, including a corrosion vessel 1, a heating device 2, a stirring device 3, and a stage 5. The heating device 2 is used to heat the corrosion vessel 1. The stirring device 3 includes a rotary drive device 31 and a stirring assembly. The fixed end of the rotary drive device 31 is fixedly mounted on the corrosion vessel 1, and the driving end of the rotary drive device 31 is fixedly connected to the stirring assembly. The stirring assembly extends into the corrosion vessel 1 to stir the cooling medium inside the corrosion vessel 1. The stage 5 is set inside the corrosion vessel 1 to hold the corrosion sample. The corrosion vessel 1 is provided with a gas inlet 6, which is used to introduce mixed hydrogen gas or mixed oxygen gas to adjust the oxygen concentration inside the corrosion vessel 1. A rotary drive device 31 drives the stirring assembly to form a controllable and stable coolant flow field within the corrosion vessel 1. This simulates the high-speed flow and scouring environment of fourth-generation fast reactor coolants, including liquid lead-bismuth, liquid sodium, liquid molten salt, and high-temperature critical water. This overcomes the limitations of traditional test devices that can only perform static immersion corrosion, realistically reproducing the scouring-corrosion coupling effect between the flowing medium and the material surface. The obtained data on material corrosion rate, film growth patterns, and fatigue degradation characteristics are more consistent with the actual service conditions of the reactor, providing reliable support for the selection of fast reactor structural materials, life prediction, and safety evaluation. A dedicated gas inlet 6 is provided on the corrosion vessel 1, allowing for flexible introduction of mixed hydrogen or mixed oxygen gases to regulate the oxygen concentration within the vessel and stably maintain it within the target range. For liquid lead-bismuth / sodium, the protective oxide film formation conditions can be adjusted; for molten salt, the redox potential can be precisely controlled; and for high-temperature critical water, the dissolved oxygen level can be stabilized. One device is compatible with the oxygen control requirements of multiple fast reactor coolants.

[0025] This device is a universal erosion corrosion testing platform, simultaneously adaptable to four mainstream fourth-generation fast reactor coolant environments: liquid lead-bismuth, liquid sodium, liquid molten salt, and high-temperature critical water. It eliminates the need for separately designed equipment for different media, significantly reducing the cost of platform construction and space requirements. The device features a modular structure and standardized interfaces, facilitating sample replacement, media switching, and component maintenance. It can meet the batch testing needs of universities, research institutes, and nuclear power companies for the corrosion performance of materials under multiple systems and operating conditions, offering multi-functionality and significantly improving testing efficiency and economy.

[0026] In a preferred embodiment, the corrosion vessel 1 is also provided with an exhaust gas outlet 7, which is connected to an exhaust gas treatment device. The exhaust gas treatment device contains activated carbon to adsorb excess metal vapor in the exhaust gas. The rotary drive device 31 is configured as a rotary pump, which requires a centrifugal pump-specific sealing structure, including a shaft sleeve, a stop sealing assembly, and a dry gas sealing assembly. The shaft sleeve is fitted and fixed to the outer surface of the main shaft, and a medium-side pressure cover is provided on the outside of the pump body. The stop sealing assembly consists of a split ring, a stop sealing ring, a stop sealing cavity, and a stop sealing cover. The dry gas sealing assembly includes a dry gas sealing cavity, a double-end dry gas sealing structure, a spring seat, and springs B and C.

[0027] In some embodiments, the corrosion vessel 1 includes a vessel body 101 and a vessel lid 102. The vessel lid 102 is disposed on top of the vessel body 101 and forms a sealed connection. Specifically, the vessel lid 102 and the vessel body 101 are sealed with bolts, and a high-temperature copper gasket is used for sealing to prevent high-temperature leakage. If the maximum operating temperature of the corrosion vessel 1 exceeds 550 degrees Celsius, the vessel lid 102 and the vessel body 101 need to be water-cooled to maintain the thermal deformation of the gasket. When the maximum operating temperature of the device exceeds 550°C, a water-cooling channel can be added at the flange of the vessel lid 102 and the vessel body 101 to reduce the working temperature of the gasket by circulating cooling water, effectively suppressing the thermal deformation and aging of the gasket, and significantly improving the sealing reliability under high-temperature conditions. The split-type top-opening structure provides the maximum internal operating space for the test operation. Before and after the test, corrosion samples can be directly clamped and disassembled vertically from the top without tilting, flipping, or moving the high-temperature vessel body 101, avoiding the major safety risks of spillage and leakage of high-temperature liquid metals such as liquid lead bismuth and liquid sodium; at the same time, multiple sets of parallel samples can be installed simultaneously, improving test efficiency. After the experiment, the residual cooling medium and corrosion products in the vessel can be cleaned directly from the top. This is especially useful for liquid lead-bismuth alloys with high freezing points and easy adhesion. Opening the top cover facilitates thorough cleaning after heating and melting. At the same time, it is convenient to inspect and replace vulnerable parts such as alumina ceramic lining, stirring blades 33, and stage 5 without disassembling the entire device.

[0028] In some embodiments, the test apparatus for general erosion corrosion in a fast reactor coolant environment further includes support frames 4. Multiple support frames 4 are arranged circumferentially around the vessel body 101. The top of the support frames 4 is fixedly connected to the vessel body 101, and the bottom of the support frames 4 is fixedly connected to the ground. The multiple circumferentially distributed support frames 4 form a closed rigid force ring, which can evenly distribute the dynamic load generated by the rotating system to each support point and transfer it to the ground, effectively suppressing all degrees of freedom vibration (lateral, axial, and torsional) of the vessel body 101. This ensures that at the highest rotational speed, the vibration displacement of the vessel body 101 is small, and the flow field uniformity deviation is minimal, ensuring that all corrosion samples are in a consistent erosion environment, improving the accuracy of test data and the comparability of parallel samples. The circumferential multi-support frame structure 4 provides all-around rigid positioning for the vessel body 101, effectively preventing positional shifts and tilting of the vessel body 101 during transportation, installation, and operation. During installation, the levelness of the vessel body 101 can be calibrated by adjusting the anchor bolts at the bottom of each support frame 4, thereby ensuring the coaxiality of the stirring shaft and the vessel body 101.

[0029] In some embodiments, the stage 5 includes a fixed shaft 51 and a stage body 52. ​​The fixed shaft 51 is fixedly connected to the vessel cover 102, and the stage body 52 is detachably connected to the fixed shaft 51, specifically through a threaded connection. A thermocouple is located near the stage body 52. ​​The fixed shaft 51 is vertically installed via a dedicated flange on the vessel cover 102, allowing for precise control of coaxiality and perpendicularity within a small range. This ensures that the stage body 52 is always positioned at the optimal scouring height and radial position of the stirring blades 33. The symmetrical arrangement of the dual stages 5 ensures minimal spatial deviation between the two stages 52, placing all parallel samples in completely identical flow, temperature, and oxygen concentration fields. This eliminates data dispersion caused by differences in stage 5 position, and the relative deviation of parallel sample test results can be controlled within a small range. The stage body 52, directly immersed in high-temperature, highly corrosive media, is a major vulnerable component. The split design allows for individual replacement of the stage body 52 when damaged, eliminating the need to replace the entire stage 5. Furthermore, different specifications of the stage 52 can be quickly replaced according to different test requirements, such as adapting to corrosion samples of different sizes and shapes (cylindrical, sheet-like, tubular), or stage 52 that can simultaneously install more parallel samples, without modifying the main structure of the device, thus enabling one device to meet the needs of multiple test schemes. The thermocouple temperature measuring end is close to the corrosion sample, measuring the temperature of the medium in a micro-region around the sample, rather than the macroscopic average temperature inside the vessel, which can accurately reflect the actual temperature of the sample surface.

[0030] In some embodiments, multiple stages 5 are provided within the corrosion vessel 1, and all stages 5 are equidistant from the stirring assembly. Preferably, two stages 5 are provided, one on each side of the stirring assembly, with the two stages 5 aligned with the stirring assembly. All samples experience identical coolant flow rates, turbulence intensity, and wall shear stress, and the scouring angle is consistent, eliminating uneven scouring conditions caused by positional differences. The multi-stage design allows for the simultaneous acquisition of two or more sets of parallel sample data in a single experiment, eliminating the need to repeat experiments under identical conditions. This shortens the experimental cycle, reduces energy consumption and media loss, and avoids systematic errors caused by differences in equipment status, environmental conditions, and operation between multiple experiments. The consistency and comparability of the data are far superior to the results of multiple repeated experiments.

[0031] In some embodiments, the stirring assembly includes a stirring shaft 32 and stirring blades 33. The stirring blades 33 are hinged to the stirring shaft 32 and can be locked by a locking device, which can be bolts. The physical properties of the four mainstream coolants for fourth-generation fast reactors (liquid lead-bismuth, liquid sodium, liquid molten salt, and high-temperature critical water) differ significantly: liquid lead-bismuth has a density more than 10 times that of water, liquid sodium has a viscosity only 1 / 3 that of water, and the viscosity of molten salt changes significantly with temperature. The hinged arrangement of the stirring blades 33 and the stirring shaft 32 enables the versatility of the angle-adjustable lifting device, allowing one set of components to be compatible with all fast reactor coolants.

[0032] In some embodiments, the heating device 2 is a high-temperature furnace, and the vessel body 101 is disposed inside the high-temperature furnace to achieve uniform heating in an enclosed manner, ensuring the uniformity of heating of the vessel body 101. The heating element is completely located inside the furnace chamber of the high-temperature furnace and is completely isolated from the test medium inside the corrosion vessel 1, so that no chemical reaction occurs between the heating element and the high-temperature medium, and the leaching of heating elements to contaminate the test medium is avoided.

[0033] In some embodiments, the inner wall of the reactor vessel 101 is coated with an alumina ceramic liner with a thickness of not less than 15 micrometers. The four mainstream coolants for Generation IV fast reactors (liquid lead-bismuth, liquid sodium, liquid molten salt, and high-temperature critical water) are all highly corrosive: liquid lead-bismuth dissolves elements such as iron, chromium, and nickel in stainless steel, causing mass migration; liquid sodium causes intergranular corrosion with metals; liquid molten salt causes electrochemical corrosion; and high-temperature critical water leads to stress corrosion cracking. The alumina ceramic liner in this embodiment has excellent chemical inertness and does not react chemically with any of the four fast reactor coolants below 1000°C, thus blocking the corrosion path of the coolant to the metal reactor vessel 101. The design with a thickness of not less than 15 μm ensures that the coating is free of pinholes, cracks, and defects, forming a continuous and complete protective barrier, reducing the corrosion rate of the reactor vessel 101 and extending its service life. Simultaneously, this liner can resist the high-speed scouring of suspended particles in the coolant and will not peel off or fail due to long-term dynamic scouring.

[0034] In some embodiments, the test apparatus for general erosion corrosion in a fast reactor coolant environment further includes an oxygen concentration monitoring device 8, which is fixedly mounted on the vessel body 101, with its probe extending into the vessel body 101. The oxygen probe extends directly into the liquid medium inside the vessel, and its installation height is completely consistent with the stage 5. It measures the true oxygen concentration in a micro-area around the corrosion sample, resulting in smaller measurement errors and faster response times. This avoids data distortion caused by measurement position deviations and lags, and can accurately capture instantaneous changes in oxygen concentration during the test, providing reliable basic data for studying the influence of oxygen concentration on the corrosion behavior of materials.

[0035] The specific oxygen concentration monitoring device 8 is a high-temperature oxygen concentration sensor, comprising a housing, a cap, and a high-temperature resistant end cap tube (preferably zirconia ceramic). The cap and the high-temperature resistant end cap tube are sealed at both ends of the housing. A solid electrolyte is filled inside the housing near the end of the high-temperature resistant end cap tube. A conductive wire passes through the cap, contacting the solid electrolyte. A modular design is adopted, with the solid electrolyte independently filled in the cavity formed by the high-temperature resistant end cap tube and the housing. The corresponding electrolyte can be quickly replaced according to the experimental medium type: when testing liquid lead-bismuth alloy or liquid sodium, an equiatomic ratio mixed Cu / Cu2O electrolyte is used; when testing molten salt or high-temperature water environments, a platinum foil electrolyte is used. One sensor housing can be adapted to all mainstream coolant media of fourth-generation fast reactors, achieving multi-media universal adaptation and reducing sensor usage costs. The cap and the high-temperature resistant zirconia ceramic end cap are respectively sealed and welded to both ends of the stainless steel shell, forming a double sealing barrier to prevent the possibility of media infiltration. The zirconia ceramic end cap not only has excellent high temperature resistance and resistance to liquid metal / molten salt corrosion, but also has good oxygen ion conduction characteristics, which allows oxygen ions to pass freely while blocking the intrusion of liquid media.

[0036] Another simplified diagram of the oxygen control gas circuit is as follows: Figure 2 As shown.

[0037] The oxygen control device includes a hydrogen-mixed and an oxygen-mixed cylinder 9. The hydrogen mixture consists of 95% Ar + 5% H2, and the oxygen mixture consists of 95% Ar + 5% O2. The hydrogen-mixed and oxygen-mixed cylinder 9 is used to reduce or increase the oxygen concentration of the liquid medium in the corrosion vessel 1. When the oxygen concentration is high, the hydrogen mixture is introduced to reduce oxygen molecules in the medium; when the oxygen concentration is low, the oxygen mixture is introduced to increase oxygen molecules in the liquid medium. The gas inlet 6 is connected to the outlet of the hydrogen-mixed and oxygen-mixed cylinder 9, and the gas inlet pipeline is equipped with a gas mass flow meter 11 and a shut-off valve 10 to achieve flow regulation and monitoring.

[0038] The oxygen concentration signal of the lead-bismuth alloy inside the reactor in the oxygen control circuit is measured by a probe. The measured oxygen potential signal is read by a digital multimeter 14, which needs to meet the measurement range of 0.1-1000mV. The oxygen potential signal is converted into a digital signal and transmitted to the control host 15 via the 485 communication protocol. The thermocouple inside the reactor is not only used to transmit the temperature signal to the control host 15 in real time, but also forms the negative electrode of the galvanic cell reaction with the oxygen probe, serving as the measurement reference for the probe's oxygen potential. The control host 15 includes functions for oxygen potential signal processing and gas flow control. The voltage digital signal of the corrosion reactor 1 is converted into the real-time oxygen concentration inside the reactor using the temperature, and the gas flow is automatically controlled using PID control. The control host 15 sends a control signal to the gas mass flow meter 11 in real time according to the oxygen concentration to achieve control of the oxygen concentration inside the reactor. The shut-off valve 10 is used for manual adjustment of the gas flow. The exhaust outlet 7 is connected to the exhaust pipeline. The pressure gauge 13 is installed on the exhaust pipeline to monitor the internal pressure of the corrosion vessel 1 in real time. A check valve 12 is also installed on the exhaust pipeline to achieve unidirectional output of exhaust gas and prevent backflow.

[0039] Example 2 This embodiment provides a test method for general erosion corrosion in a fast reactor coolant environment, implemented using the test apparatus for general erosion corrosion in a fast reactor coolant environment described in Embodiment 1, and includes the following steps: Step 1: Use heating device 2 to heat corrosion vessel 1 to the target temperature and control the oxygen concentration to the target value; Step 2: Stop the gas supply and reduce the temperature of corrosion vessel 1 to the set value (150℃). Step 3: Load the corrosion sample onto stage 5 and install stage 5 into corrosion vessel 1; Step 4: Reheat the corrosion vessel 1 using heating device 2 and introduce gas through gas inlet 6 to adjust the oxygen concentration, and turn on stirring device 3; Step 5: Start timing when the oxygen concentration reaches the target value, and end the test when the target time is reached; Step 6: Stop the gas flow through gas inlet 6, cool the corrosion vessel 1 to the set value (150℃), and remove the corrosion sample from the stage 5.

[0040] The process employs a pre-set target operating condition, followed by low-temperature sample loading and steady-state startup. Step one involves heating the corrosion vessel 1 to the target temperature and stabilizing the oxygen concentration at the target value, thus establishing test conditions completely consistent with the actual service environment of the fast reactor. Simultaneously, it verifies the normal operation of the heating, oxygen control, and sealing systems. Step two involves lowering the temperature only to a safe operating temperature of 150℃, maintaining the medium inside the vessel in a liquid state and ensuring a relatively stable oxygen concentration to avoid compositional changes and oxygen concentration fluctuations caused by solidification and remelting. Step four involves rapidly reheating the vessel 101 to the target temperature and restoring the oxygen concentration to the target value. The entire process is relatively short, significantly reducing the exposure time of the sample under non-target operating conditions. This ensures that the corrosion sample corrodes almost exclusively under the preset stable temperature, oxygen concentration, and flow rate conditions. The initial oxide film formation environment is completely consistent with the test conditions, and the measured data on corrosion rate, oxide film growth kinetics, and mass migration patterns accurately reflect the intrinsic corrosion performance of the material.

[0041] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A test apparatus for general erosion corrosion in fast reactor coolant environments, characterized in that: The system includes a corrosion vessel, a heating device, a stirring device, and a stage. The heating device heats the corrosion vessel. The stirring device includes a rotary drive and a stirring assembly. The fixed end of the rotary drive is fixedly mounted on the corrosion vessel, and the driving end is fixedly connected to the stirring assembly. The stirring assembly extends into the corrosion vessel to stir the cooling medium inside. The stage is placed inside the corrosion vessel to hold the corrosion sample. The corrosion vessel has a gas inlet for introducing mixed hydrogen or mixed oxygen gas to adjust the oxygen concentration inside the corrosion vessel.

2. The test apparatus for general erosion corrosion in a fast reactor coolant environment according to claim 1, characterized in that: The corrosion vessel includes a vessel body and a vessel lid, the vessel lid being disposed on top of the vessel body and capable of forming a sealed connection.

3. The test apparatus for general erosion corrosion in a fast reactor coolant environment according to claim 2, characterized in that: It also includes a support frame, of which multiple support frames are arranged around the circumference of the vessel body. The top of the support frame is fixedly connected to the vessel body, and the bottom of the support frame is fixedly connected to the ground.

4. The test apparatus for general erosion corrosion in a fast reactor coolant environment according to claim 2, characterized in that: The stage includes a fixed shaft and a stage body. The fixed shaft is fixedly connected to the vessel lid, and the stage body is detachably connected to the fixed shaft. A thermocouple is provided near the stage body.

5. The test apparatus for general erosion corrosion in a fast reactor coolant environment according to claim 4, characterized in that: Multiple platforms are provided inside the corrosion vessel, and all platforms are at the same distance from the stirring assembly.

6. The test apparatus for general erosion corrosion in a fast reactor coolant environment according to claim 1, characterized in that: The stirring assembly includes a stirring shaft and stirring blades. The stirring blades are hinged to the stirring shaft and can be locked by a locking device.

7. The test apparatus for general erosion corrosion in a fast reactor coolant environment according to claim 2, characterized in that: The heating device is a high-temperature furnace, and the vessel body is disposed inside the high-temperature furnace.

8. The test apparatus for general erosion corrosion in a fast reactor coolant environment according to claim 2, characterized in that: The inner wall of the vessel is coated with an alumina ceramic lining with a thickness of not less than 15 micrometers.

9. The test apparatus for general erosion corrosion in a fast reactor coolant environment according to claim 2, characterized in that: It also includes an oxygen concentration monitoring device, which is fixedly installed on the vessel body, and the probe of the oxygen concentration monitoring device extends into the vessel body.

10. A test method for general erosion corrosion in fast reactor coolant environments, characterized in that: The test is conducted using the universal erosion corrosion test apparatus for fast reactor coolant environments as described in any one of claims 1-9, and includes the following steps: Step 1: Heat the corrosion vessel to the target temperature using a heating device, and control the oxygen concentration to the target value; Step 2: Stop the gas supply and reduce the temperature of the corrosion vessel to the set value; Step 3: Load the corrosion sample onto the stage and install the stage into the corrosion vessel; Step 4: Reheat the corrosion vessel using a heating device, introduce gas through the gas inlet to adjust the oxygen concentration, and turn on the stirring device; Step 5: Start timing when the oxygen concentration reaches the target value, and end the test when the target time is reached; Step 6: Stop the gas flow through the gas inlet, cool the corrosion vessel to the set value, and remove the corrosion sample from the stage.

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