Plate-type fuel assembly washout test device and method

Abstract

The invention discloses a plate-type fuel assembly washout test device and method, and belongs to the field of nuclear power. The plate type fuel assembly washout test device comprises a washout test loop and a water quality adjusting branch, the washout test loop comprises a water supply pipeline and a test section, a pump set of the water supply pipeline provides circulating power for test water, and a fuel plate test piece is arranged in the test section and provides washout test working conditions; the water quality adjusting loop is communicated with the water supply pipeline and can adjust the pH value of the test water and filter out impurities in the test water. The device can keep the water chemical condition stable in the long-term test process, and improves the scouring test precision of the plate-type fuel assembly.

Description

Technical Field

[0001] The invention belongs to the field of nuclear power, and particularly relates to a plate - type fuel assembly erosion test device and method. Background Art

[0002] The plate - type fuel assembly has a compact structure, a large heat flux density, and good heat transfer efficiency, and has been widely used in reactor types such as power reactors, material reactors, neutron reactors, and test reactors. The structural characteristics of the plate - type fuel assembly lead to the risk of structural integrity and dimensional stability during long - term cooling medium erosion. Therefore, it is necessary to carry out long - term erosion tests on the plate - type fuel assembly to verify and analyze its durability. During the long - term erosion test, it is necessary to accurately simulate the service environment of the plate - type fuel assembly, especially the water chemistry conditions. The pH and conductivity in the cooling water will have a significant impact on the test reliability. During the long - term operation of the test pipeline under high - temperature and high - pressure conditions, soluble and insoluble impurities are inevitably generated, which have an adverse impact on the test results. However, the existing test benches for plate - type fuel assemblies cannot meet the requirement of accurately controlling the water chemistry conditions. Therefore, providing a plate - type fuel assembly erosion test device that can accurately adjust the water chemistry conditions is of positive significance for improving the accuracy of the plate - type fuel assembly erosion test. Summary of the Invention

[0003] The purpose of the invention is to provide a plate - type fuel assembly erosion test device to accurately control the water chemistry conditions in the plate - type fuel assembly erosion test. The invention also provides a plate - type fuel assembly erosion test method.

[0004] According to an embodiment of one aspect of the invention, a plate - type fuel assembly erosion test device is provided. The device includes an erosion test loop and a water quality adjustment branch. Among them, the erosion test loop includes a water supply pipeline and a test section, and the test water circulates between the water supply pipeline and the test section; the water supply pipeline includes a pump group, the pump group provides the circulating power of the test water, and a fuel plate test piece is arranged in the test section to provide an erosion test condition. The water quality adjustment branch is connected to the water supply pipeline and allows at least part of the test water to be injected into the water quality adjustment branch during the circulation process and then return to the water supply pipeline; the water quality adjustment branch includes a water quality adjustment module, and the water quality adjustment module filters out impurities in the test water and adjusts the pH value of the test water.

[0005] Under the plate - type fuel assembly erosion test condition, the test pipeline is in contact with high - temperature and high - pressure test water for a long time, and impurity ions are easily dissolved into the test water, resulting in changes in pH value and conductivity, which affect the test accuracy. By setting up the water quality adjustment branch, the pH value and conductivity of the test water can be adjusted according to the test needs, so as to ensure the stability of the physical and chemical properties of the test water during the test process and improve the test accuracy.

[0006] Further, in some embodiments, the water quality adjustment branch is in a parallel relationship with the test section.

[0007] Further, in some embodiments, the water quality adjustment module includes an ion exchange column and a mixing column. The ion exchange column is used to adjust the pH value of the test water, and the mixing column is used to separate free ions from the test water.

[0008] Further, in some embodiments, the ion exchange column and the mixing column are in a parallel relationship.

[0009] Further, in some embodiments, the ion exchange column is configured as a cation exchange column.

[0010] Further, in some embodiments, the water quality adjustment branch further includes a cooler, and the cooler is disposed upstream of the water quality adjustment module.

[0011] Further, in some embodiments, the device further includes a makeup water branch, and the makeup water branch is connected to the water supply pipeline. The makeup water branch injects the test water into the water supply pipeline.

[0012] Further, in some embodiments, the makeup water branch includes a water tank and a plunger pump. The water tank stores the test water, and the plunger pump pumps the test water into the water supply pipeline.

[0013] Further, in some embodiments, the device further includes a pH measuring device and a conductivity measuring device.

[0014] Further, in some embodiments, the test section includes a simulated core grid plate. The fuel plate test piece is fixedly installed on the simulated core grid plate, and the simulated core grid plate provides a constraint boundary for the fuel plate test piece.

[0015] According to an embodiment of another aspect of the present invention, there is provided a method for flushing a plate-type fuel assembly. This method uses the plate-type fuel assembly flushing test device provided in any of the foregoing embodiments. The method includes the following steps:

[0016] Step a): Load the fuel plate test piece into the test section;

[0017] Step b): Inject test water meeting given conditions into the water supply pipeline;

[0018] Step c): Adjust the water in the water supply pipeline to given temperature, pressure, flow rate, and water chemistry conditions, and start the flushing test;

[0019] Step d): Use the water quality regulation module to maintain the water chemical conditions within a given range until the end of the test. Description of the Drawings

[0020] Figure 1 It is a schematic structural diagram of a plate fuel assembly flushing test device in an embodiment.

[0021] Meanings of the reference numerals:

[0022] 1 - test section; 2 - water supply pipeline; 3 - water quality regulation branch; 4 - makeup water branch; 5 - cation exchange column; 6 - mixing column; 7 - cooler; 8 - heater; 9 - pH meter; 10 - conductivity and ion concentration detection device; 11 - pressure gauge; 12 - thermometer; 13 - flowmeter; 14 - canned motor pump; 15 - small flow piston pump; 16 - makeup water tank; 17 - filter; 18 - pressure stabilizing tank.

[0023] The purpose of the above drawings is to make a detailed description of the present invention so that those skilled in the art can understand the technical concept of the present invention, rather than to limit the present invention. For the sake of simplicity of expression, the above drawings only schematically show the structures related to the technical features of the present invention, and do not strictly draw the complete structure and all details according to the actual proportion. Detailed Embodiments

[0024] The present invention will be further described in detail below through specific embodiments in conjunction with the drawings.

[0025] The mention of "embodiment" in this article means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of this article. The phrase appearing at various positions in the specification does not necessarily refer to the same embodiment, nor is it limited to mutually exclusive independent or alternative embodiments. Those skilled in the art should be able to understand that the embodiments in this article can be combined with other embodiments without structural conflict.

[0026] In the description of this article, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", "connection" should be understood in a broad sense. For example, it can be a movable connection, a fixed connection or integrated. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of this application can be understood according to specific situations.

[0027] In the description of this article, terms indicating orientation or positional relationships such as "upper", "lower", "left", "right", "horizontal", "vertical", "height", "length", "width" are intended to accurately describe the embodiments and simplify the description, rather than limiting the parts or structures involved to have a specific orientation, be installed or operated in a specific orientation, and should not be construed as a limitation to the embodiments in this article.

[0028] In the description of this article, terms such as "first" and "second" are only used to distinguish different objects, and cannot be understood as indicating relative importance or limiting the quantity, specific order or primary-secondary relationship of the described technical features. In the description of this article, the meaning of "a plurality of" is at least two.

[0029] The main structure of the plate-type fuel assembly includes fuel plates, side plates, tube sockets, lifting beams, positioning combs and fasteners, etc. After being continuously scoured by high-temperature and high-pressure cooling medium for a long time, the dimensional stability of the fuel assembly (including the thickness of the fuel plates, the water gap size between the fuel plates, etc.) and the structural integrity (including the assembly relationship between the side plates and the tube sockets, positioning combs, positioning pins, fastening screws, the external integrity of the fuel plates, the surface quality of the assembly, etc.) are affected. Therefore, before being officially put into application, a long-term scouring test needs to be carried out on the plate-type fuel assembly to verify and analyze its durability. The long-term scouring test needs to accurately simulate the actual working conditions of the plate-type fuel assembly in the reactor. Usually, conditions such as temperature, pressure, scouring flow rate, etc. can be accurately controlled by reasonably setting the parameters of the water supply system. However, the water chemical conditions (pH value, conductivity, etc.) during the test process are likely to change due to the corrosion of components such as pipelines and the precipitation of impurity ions, affecting the final test results. At present, the existing scouring test device for plate-type fuel assemblies lacks a solution for accurately controlling the water chemical conditions, which is not conducive to improving the accuracy of the scouring test of plate-type fuel assemblies.

[0030] To solve the above problems, an embodiment of one aspect of the present invention provides a scouring test device for a plate-type fuel assembly, and the structure of the device is as Figure 1 shown, including a scouring test loop and a water quality adjustment branch 3. Among them, the scouring test loop includes a test section 1 and a water supply pipeline 2. The water supply pipeline 2 includes a canned motor pump 14, and the canned motor pump 14 provides circulating power to make the test water circulate between the water supply pipeline 2 and the test section 1. A to-be-tested plate-type fuel assembly is installed in the test section 1, and the test section 1 provides a test working condition for the to-be-tested plate-type fuel assembly for scouring tests.

[0031] Specifically, a simulated core grid plate is arranged in the test section 1, and the fuel plate test piece is fixedly installed on the simulated core grid plate, and the simulated core grid plate provides a physical constraint boundary for the fuel plate test piece. At the same time, the test water flowing in the test section 1 has the corresponding temperature, pressure, flow rate and water chemical conditions required for carrying out scouring tests.

[0032] The water quality adjustment branch 3 is connected to the water supply pipeline 2, and the test water can be injected from the upstream of the water quality adjustment branch 3 and flow back to the water supply pipeline 2 through the downstream of the water quality adjustment branch 3 during the circulation process. By adjusting the relevant valve groups on the water quality adjustment branch 3 and the water supply pipeline 2, the proportion of the test water flowing into the water quality adjustment branch 3 can be adjusted. The water quality adjustment branch 3 includes a water quality adjustment module, which can filter out impurities in the test water and adjust the pH value of the test water. Specifically, the impurities include soluble impurity ions and insoluble impurity particles.

[0033] In different embodiments, the water quality adjustment branch 3 can be arranged at different positions of the flushing test loop. In the preferred embodiment, as Figure 1 shown, the water quality adjustment branch 3 is arranged in parallel with the test section 1.

[0034] In some embodiments, as Figure 1 shown, the water quality adjustment module in the water quality adjustment branch 3 includes an ion exchange column and a mixing column 6. The mixing column 6 is used to separate free ions from the test water to control the conductivity of the test water, and the ion exchange column is used to adjust the pH value of the test water. In the preferred embodiment, the ion exchange column adopts a cation exchange column 5, and the cation exchange column 5 is arranged in parallel with the mixing column 6. The cation exchange column 5 adjusts the pH value by replacing metal ions in the test water, so as to keep the water quality pH value within the target range.

[0035] In some embodiments, the cation exchange column 5 can also be replaced by other pH adjustment devices. For example, it can be replaced by a dosing device, and the pH value of the test water is adjusted by adding a pH regulator to the test water.

[0036] Furthermore, since the flushing test condition of the fuel plate test piece in the test section 1 is a high-temperature and high-pressure environment, the temperature of the test water flowing out of the test section 1 is relatively high, which may exceed the allowable temperature of the ion exchange membrane. Therefore, in the preferred embodiment, in the water quality adjustment branch 3, a cooler 7 is arranged upstream of the water quality adjustment module. The cooler 7 can cool the test water to prevent the ion exchange membranes in the cation exchange column 5 and the mixing column 6 from being damaged by high temperature.

[0037] In the preferred embodiment, the water supply pipeline 2 includes a pH meter 9 as a pH measurement device and a conductivity and ion concentration detection device 10 as a conductivity measurement device. Specifically, the conductivity and ion concentration detection device 10 can be set as an on-line detection device or an off-line detection device. The pH meter 9 and the conductivity and ion concentration detection device 10 are used to monitor the water chemical conditions (pH value, conductivity) of the test water in the test device to ensure the stability of the flushing test water chemical conditions.

[0038] In some embodiments, a makeup water branch 4 is further provided on the water supply pipeline 2. The makeup water branch 4 includes a makeup water tank 16 which stores a sufficient amount of test water and can supply water to the water supply pipeline 2 during the test to ensure that there is always a sufficient amount of test water participating in the test cycle. The makeup water tank 16 is connected to the water supply pipeline 2 through a small flow rate plunger pump 15, and the small flow rate plunger pump 15 pumps the test water stored in the makeup water tank 16 into the water supply pipeline 2 to achieve the supplement of the test water.

[0039] According to an embodiment of another aspect of the present invention, a method for flushing test of a plate-type fuel assembly is provided, and this method uses the plate-type fuel assembly flushing test device provided in the foregoing embodiments.

[0040] In one embodiment, a method for flushing test of a plate-type fuel assembly as shown in Figure 1 is adopted, and the steps are as follows:

[0041] Step a): Install the fuel plate test piece into the test section 1 and install it on the simulated core grid plate, and the simulated core grid plate provides a physical constraint boundary according to the actual state in the simulated reactor. In different embodiments, the fuel plate test piece can be made of different materials. For example, a real fuel plate sample can be used, or a low-radioactivity uranium-containing plate can be used, or a simulated sample plate simulating the physical properties of the fuel plate with non-radioactive elements can be used.

[0042] After the fuel plate test piece is installed, keep the flushing test loop unblocked and open the exhaust valve of the pipeline.

[0043] Step b): Open the valve between the makeup water branch 4 and the water supply pipeline 2, start the small flow rate plunger pump 15, and inject the test water in the makeup water tank 16 into the flushing test loop. The test water in the makeup water tank 16 can be pure water or other solutions meeting the requirements of the test design. After the flushing test loop is filled, cut off the valve between the makeup water branch 4 and the water supply pipeline 2.

[0044] Step c): Adjust the temperature, pressure, flow rate and water chemistry conditions of the test water in the flushing test loop. Specifically, adjust the pH value through the cation exchange column 5 in the water quality adjustment module, filter out the impurity ions in the test water through the mixing column 6 to adjust the conductivity of the test water, heat the test water through the heater 8 provided on the water supply pipeline 2 and use the cooler 7 to cool to maintain the temperature stability, and use the pressure stabilizing tank 18 to maintain the pipeline pressure stability. Measure the flow rate of the test water through the flow meter 13, measure the pressure of the test water through the pressure gauge 11, measure the temperature of the test water through the thermometer 12, measure the pH value of the test water through the pH meter 9, and measure the conductivity of the test water through the conductivity and ion concentration detection device 10. After determining that each parameter reaches the range specified by the test design requirements, start the flushing test.

[0045] Step d): During the flushing test, use the water quality adjustment module to adjust the pH value and conductivity of the test water to maintain the water chemistry adjustment within the range specified by the test design requirements at all times.

[0046] Specifically, the cation exchange column 5 is connected to the flushing test loop for 20 min - 30 min every 3 h - 5 h, and hydrogen ions are used to replace metal ions in the test loop to achieve stable adjustment of the pH value of the test water until the end of the test.

[0047] The above method can maintain the stability of water chemistry conditions during the long-term flushing test of the fuel plate, avoid adverse effects of pH value or conductivity fluctuations on the test results, and improve the accuracy of the flushing test of the plate-type fuel assembly.

[0048] The purpose of the above embodiments is to further elaborate on the present invention in conjunction with the accompanying drawings so that those skilled in the art can understand the technical concept of the present invention. Within the scope disclosed by the present invention, optimizing or equivalently replacing the component structures or method steps involved, and combining the implementation manners in different embodiments without conflict in structure and principle all fall within the protection scope of the present invention.

Claims

1. A plate-type fuel assembly flushing test device, characterized in that it includes a flushing test circuit and a water quality adjustment branch, wherein the flushing test circuit includes a water supply pipeline and a test section, and the test water circulates between the water supply pipeline and the test section; the water supply pipeline includes a pump set, the pump set provides the circulating power of the test water, and a fuel plate test piece is arranged in the test section and provides a flushing test condition; the water quality adjustment branch is connected to the water supply pipeline and allows at least part of the test water to be injected into the water quality adjustment branch and return to the water supply pipeline during the circulation process; the water quality adjustment branch includes a water quality adjustment module, and the water quality adjustment module filters impurities in the test water and adjusts the pH value of the test water.

2. The plate-type fuel assembly flushing test device according to claim 1, wherein The water quality adjustment branch is in a parallel relationship with the test section.

3. The plate-type fuel assembly flushing test device according to claim 1 or 2, characterized in that The water quality adjustment module includes an ion exchange column and a mixing column. The ion exchange column is used to adjust the pH value of the test water, and the mixing column is used to separate free ions from the test water.

4. The plate-type fuel assembly flushing test device according to claim 3, characterized in that The ion exchange column is in a parallel relationship with the mixing column.

5. The plate-type fuel assembly flushing test device according to claim 3, characterized in that, The ion exchange column is configured as a cation exchange column.

6. The plate-type fuel assembly flushing test device according to claim 3, wherein The water quality adjustment branch further includes a cooler, and the cooler is arranged upstream of the water quality adjustment module.

7. The plate-type fuel assembly flushing test device according to claim 1 or 2, characterized in that, It further includes a makeup water branch, the makeup water branch is connected to the water supply pipeline, and the makeup water branch injects the test water into the water supply pipeline.

8. The plate-type fuel assembly flushing test device according to claim 7, characterized in that, The makeup water branch includes a water tank and a plunger pump. The water tank stores the test water, and the plunger pump pumps the test water into the water supply pipeline.

9. The plate-type fuel assembly flushing test device according to claim 1 or 2, characterized in that It further includes a pH measuring device and a conductivity measuring device.

10. The plate-type fuel assembly flushing test device according to claim 1 or 2, characterized in that, The test section includes a simulated core grid plate, the fuel plate test piece is fixedly installed on the simulated core grid plate, and the simulated core grid plate provides a constraint boundary for the fuel plate test piece.

11. A method for flushing test of a plate-type fuel assembly, characterized in that, Using the plate-type fuel assembly flushing test device according to any one of claims 1 to 10, and including the following steps: Step a): Install the fuel plate test piece into the test section; Step b): Inject test water meeting given conditions into the water supply pipeline; Step c): Adjust the water in the water supply pipeline to given temperature, pressure, flow rate and water chemistry conditions, and start the flushing test; Step d): Use the water quality adjustment module to maintain the water chemistry conditions within a given range until the test ends.

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