Method for evaluating the decontamination performance of a reactor pool foam decontaminant

Abstract

The application discloses a kind of reactor pool foam decontaminant decontamination performance test evaluation methods, in cylindrical organic glass container is placed in desalted water or solution containing foam decontaminant, metal oxide is added, stainless steel test piece is immersed into the aqueous solution of organic glass container, and solution is stirred using stainless steel test piece, then it is fixed in organic glass container with certain inclination angle;After standing, desalted water or solution containing foam decontaminant is slowly discharged from the water drain pipe at the bottom of organic glass container, remove stainless steel test piece, and place stainless steel test piece horizontally;After the surface residual water of stainless steel test piece is dried, the deposition amount of metal oxide on the surface of test piece is obtained by comparing the surface quality of stainless steel test piece, and the influence of different foam decontaminants on the deposition amount of metal oxide on the surface of stainless steel test piece is compared.The test device of the application is simple in structure, and is suitable for performance evaluation in the development process of pressurized water reactor nuclear power plant reactor pool foam decontaminant.

Description

Technical Field

[0001] This invention belongs to the field of radiochemical decontamination technology for nuclear facilities, specifically relating to a test and evaluation method for the decontamination performance of a foam decontaminant in a reactor pool. Background Technology

[0002] To improve the power generation of pressurized water reactor nuclear power units, nuclear power plants strive to optimize the overhaul schedule, with reactor pool decontamination being a key component of the overhaul process. Currently, in China, high-pressure water flushing combined with manual wiping is commonly used for pool decontamination. Guan Haiyang et al. from Ningde Nuclear Power reported on the foam decontamination process of a nuclear power plant's refueling pool:

[0003] First, a foam detergent was sprayed into the reactor pool, followed by high-pressure water rinsing, manual scraping, and wiping. The following effects were achieved through foam detergent removal:

[0004] 1) The dose rate at the bottom of the pool was reduced, and the power station requirements could be met after simple wiping and cleaning.

[0005] 2) Reduced the amount of waste generated during the wiping stage;

[0006] 3) It shortened the decontamination time of the reactor pool.

[0007] The main deposits at the bottom of the reactor pool in a pressurized water reactor (PWR) nuclear power plant are activated corrosion products. These substances exist in the form of loose sediments, and their removal primarily relies on the stripping action of high-pressure water during the high-pressure water flushing stage. Foaming detergents have limited ability to enhance the stripping effect of high-pressure water on sediments, but they do have a coating effect on the stripped sediments, preventing them from being re-deposited in other areas of the pool bottom during high-pressure water flushing. This allows the sediments stripped by high-pressure water to be carried into the drainage channel by the water flow, thus improving the efficiency of high-pressure water flushing.

[0008] Therefore, the ability of foam detergents to coat and prevent secondary deposition of stripped deposits is particularly important in industrial applications. In the development of foam detergents for reactor pools, there are currently no relevant standards or quantitative testing methods to assess the ability of foam detergents to coat and remove deposits using high-pressure water. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to provide a test and evaluation method for the decontamination performance of foam decontaminants in reactor pools, which addresses the shortcomings of the prior art and quantitatively evaluates the ability of foam decontaminants to coat deposits by high-pressure water stripping.

[0010] The present invention adopts the following technical solution:

[0011] A method for evaluating the decontamination performance of a foam detergent in a reactor pool involves adding a metal oxide to a solution containing demineralized water and a foam detergent to obtain an aqueous solution; immersing a stainless steel test piece in the aqueous solution and stirring the solution with the stainless steel test piece; then tilting the stainless steel test piece in the aqueous solution and allowing it to stand; draining the aqueous solution after standing, removing the stainless steel test piece and placing it horizontally; comparing the surface quality of the stainless steel test piece to obtain the amount of metal oxide deposited on the surface of the test piece; comparing the effects of different foam detergents on the amount of metal oxide deposited on the surface of the stainless steel test piece to achieve the evaluation of the decontamination performance.

[0012] Specifically, the volume ratio of deionized water to foam detergent in the solution is 1:(100-10).

[0013] Specifically, the metal oxide is one or more of the following: iron(II,III) oxide, cobalt oxide, and nickel oxide.

[0014] Specifically, the stirring time for the aqueous solution using a stainless steel test piece is 30 seconds to 1 minute.

[0015] Specifically, the stainless steel test piece is placed at an angle of 45° to 60°.

[0016] Specifically, the settling time is 2 to 5 minutes.

[0017] Specifically, after the residual water on the surface of the stainless steel test piece has dried, the surface quality of the stainless steel test piece is compared.

[0018] Specifically, the aqueous solution is placed in an plexiglass container.

[0019] Furthermore, the plexiglass container has a cylindrical structure.

[0020] Specifically, the stainless steel test piece was weighed using an electronic analytical balance with an accuracy of 0.1 mg.

[0021] Compared with the prior art, the present invention has at least the following beneficial effects:

[0022] A method for evaluating the decontamination performance of foam detergents in reactor pools is provided. This method can quantitatively evaluate the effect of different foam detergents on the amount of metal oxide deposition on the surface of stainless steel test pieces, and realize the evaluation and comparison of decontamination performance.

[0023] Furthermore, the volume ratio of demineralized water to foam detergent in the solution is controlled at 1:(100-10) to simulate the situation where the actual concentration of foam detergent is low during the high-pressure water rinsing stage.

[0024] Furthermore, the metal oxides selected in the experiment were one or more mixtures of iron tetroxide, cobalt oxide, and nickel oxide, used to simulate the activated corrosion products deposited at the bottom of the reactor pool in a pressurized water reactor nuclear power plant.

[0025] Furthermore, the stainless steel test piece is tilted at an angle of 45° to 60° to ensure that the test solution can be discharged quickly in the plexiglass container, simulating the drainage conditions of the reactor pool during the high-pressure water flushing stage.

[0026] Furthermore, the use of cylindrical acrylic containers helps to ensure consistency in the tilt angle of the test pieces and the drainage.

[0027] In summary, this test method closely resembles the actual operating conditions of foam detergents, and the test apparatus has a simple structure, making it suitable for performance evaluation during the development of foam detergents for pressurized water reactor nuclear power plant reactor pools.

[0028] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0029] Figure 1 This is a simplified diagram of the experimental apparatus of the present invention;

[0030] Figure 2 These are comparative photographs of oxide deposition on the surface of stainless steel test pieces in demineralized water and demineralized water containing foam detergent, wherein (a) is the surface state of the blank group after immersion, (b) is the surface state of the blank group after immersion in 1% detergent solution, and (c) is the surface state of the blank group after immersion in 1% detergent solution.

[0031] Among them, 1. cylindrical container; 2. discharge pipe; 3. stop valve; 4. sample. Detailed Implementation

[0032] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0033] Unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined to form new technical solutions.

[0034] Unless otherwise specified, all the technical features and preferred features mentioned herein can be combined to form new technical solutions.

[0035] In this invention, unless otherwise specified, percentage (%) or parts refer to weight percentage or parts relative to the composition.

[0036] Unless otherwise specified, the components or preferred components involved in this invention can be combined with each other to form new technical solutions.

[0037] In this invention, unless otherwise specified, the numerical range "a~b" represents an abbreviation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "6~22" means that all real numbers between "6~22" have been listed in this document, and "6~22" is simply an abbreviation of these numerical combinations.

[0038] The "scope" disclosed in this invention can be in the form of a lower limit and an upper limit, and can be one or more lower limits and one or more upper limits, respectively.

[0039] In this invention, the term "and / or" as used herein refers to any combination of one or more of the associated listed items, as well as all possible combinations, and includes such combinations.

[0040] In this invention, unless otherwise stated, the various reactions or operation steps may be performed sequentially or in a particular order. Preferably, the reaction methods described herein are performed sequentially.

[0041] Unless otherwise stated, the technical and scientific terms used herein have the same meanings as those familiar to those skilled in the art. Furthermore, any methods or materials similar to or equivalent to those described herein may also be used in this invention.

[0042] This invention provides a method for evaluating the decontamination performance of foam detergents in reactor pools, used to assess the decontamination performance of foam detergents on loose deposits in reactor pools. An appropriate amount of demineralized water or a solution containing foam detergent is placed in a cylindrical plexiglass container, along with metal oxides. A stainless steel test piece is immersed in the aqueous solution in the plexiglass container, and the solution is stirred using the stainless steel test piece for 30 seconds to 1 minute. The test piece is then fixed in the plexiglass container at a certain tilt angle. After the solution has settled for 2 to 5 minutes, the demineralized water or the solution containing foam detergent is slowly drained from a drain pipe at the bottom of the plexiglass container. The stainless steel test piece is then removed and placed horizontally. After the residual water on the surface of the stainless steel test piece has dried, the amount of metal oxide deposited on the surface of the test piece is obtained by comparing the surface quality. The effects of different foam detergents on the amount of metal oxide deposited on the surface of the stainless steel test piece are compared. This invention can quantitatively evaluate the decontamination performance of foam detergents on loose deposits in reactor pools, and the test device has a simple structure, making it suitable for performance evaluation during the development of foam detergents for pressurized water reactor nuclear power plants.

[0043] Please see Figure 1A device for testing and evaluating the decontamination performance of a foam decontaminant in a reactor pool includes a cylindrical container 1, a discharge pipe 2, and a stop valve 3. A sample 4 is placed inside the cylindrical container 1. The discharge pipe 2 is located at the bottom of the cylindrical container 1, with one end connected to the center of the bottom of the cylindrical container 1 and the other end equipped with the stop valve 3.

[0044] This invention discloses a method for testing and evaluating the decontamination performance of a foam decontaminant in a reactor pool, comprising the following steps:

[0045] S1. Add an appropriate amount of desalination water or an aqueous solution containing foam detergent to the plexiglass container;

[0046] The acrylic container is cylindrical.

[0047] In aqueous solution, the volume ratio of foam detergent to deionized water is 1:(100-10).

[0048] S2. Add a certain amount of metal oxide to the plexiglass container and stir with a glass rod;

[0049] The metal oxide is one or more of the following: iron(II,III) oxide, cobalt(II) oxide, and nickel(II) oxide.

[0050] S3. Immerse the stainless steel test piece in the aqueous solution of the plexiglass container and stir the solution with the stainless steel test piece for 30 seconds to 1 minute, and then fix it in the plexiglass container at a certain tilt angle.

[0051] The stainless steel test piece is tilted at an angle of 30° to 45° in the plexiglass container.

[0052] S4. After the solution has stood for 2 to 5 minutes, slowly release the demineralized water or the solution containing foam detergent from the drain pipe at the bottom of the plexiglass container.

[0053] S5. Take out the stainless steel test piece and place it horizontally. After the residual water on the surface of the stainless steel test piece dries in the shade, the amount of metal oxide deposited on the surface of the test piece is obtained by comparing the surface quality of the stainless steel test piece.

[0054] The stainless steel specimen was weighed using an electronic analytical balance with an accuracy of 0.1 mg.

[0055] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0056] Example 1

[0057] Detergent A is composed of alkyl glycosides, xanthan gum, diethylenetriaminepentaacetic acid, ethanolamine, etc.

[0058] First, conduct a blank experiment:

[0059] Take a stainless steel test piece (10cm long, 6cm wide, and 0.5cm high) and weigh it to obtain its mass m0. Place the stainless steel test piece into an acrylic container (15cm high and 10cm in diameter) and tilt it at an angle of 50°.

[0060] Add 800mL of deionized water to a 1L beaker, then add 0.3g of iron oxide powder (commercially available), and stir with a glass rod to evenly disperse the iron oxide powder in the solution;

[0061] Pour the solution containing iron oxide powder into an acrylic container containing the test piece, let it stand for 5 minutes, and then drain the solution from the drain pipe at the bottom of the acrylic container.

[0062] Take out the stainless steel test piece and place it horizontally. After the residual water and deposits on the surface of the stainless steel test piece are completely dry, weigh it and record the mass as m1. Calculate the mass difference Δm1(m1-m0) of the test piece before and after the test to obtain the amount of metal oxide deposited on the surface of the test piece.

[0063] Then, a comparative experiment was conducted:

[0064] Take a stainless steel test piece (10cm long, 6cm wide, and 0.5cm high) and weigh it to obtain its mass m0. Place the stainless steel test piece into an acrylic glass container (15cm high and 10cm in diameter) and tilt it at an angle of 50°. Add 800mL of deionized water and detergent (the volume ratio of detergent to deionized water is 1:100) to a 1L beaker, and then add 0.3g of iron oxide powder (commercially available).

[0065] Stir with a glass rod to evenly disperse the iron oxide powder in the solution;

[0066] Pour the solution containing iron oxide powder into an acrylic container containing the test piece, let it stand for 5 minutes, and then drain the solution from the drain pipe at the bottom of the acrylic container.

[0067] Take out the stainless steel test piece and place it horizontally. After the residual water and sediment on the surface of the stainless steel test piece are completely dry, weigh it and record the mass as m3.

[0068] The experiment was repeated under the same conditions, except the volume ratio of detergent to demineralized water was adjusted to 2:100. After drying, the mass was recorded as m4. The mass difference Δm2(m3-m2) and Δm3(m4-m2) before and after the experiment were calculated to determine the amount of iron oxide powder deposited on the surface of the test piece. Comparative photographs of iron oxide powder deposition on the surface of stainless steel test pieces in demineralized water and demineralized water containing foam detergent are shown below. Figure 2 As shown.

[0069] Compare Δm1, Δm2, and Δm3 to use as the basis for evaluating the detergency of detergent A.

[0070]

[0071] Example 2

[0072] Detergent B is composed of alkyl glycosides, xanthan gum, polyacrylic acid, ethanolamine, etc.

[0073] First, conduct a blank experiment:

[0074] Take a stainless steel test piece (10cm long, 6cm wide, and 0.5cm high) and weigh it to obtain its mass m0. Place the stainless steel test piece into an acrylic container (15cm high and 10cm in diameter) and tilt it at an angle of 40°.

[0075] Add 1L of deionized water to a 1L beaker, then add 0.5g of iron oxide powder (commercially available), and stir with a glass rod to evenly disperse the iron oxide powder in the solution;

[0076] Pour the solution containing iron oxide powder into an acrylic container containing the test piece, let it stand for 10 minutes, and then drain the solution from the drain pipe at the bottom of the acrylic container.

[0077] Take out the stainless steel test piece and place it horizontally. After the residual water and deposits on the surface of the stainless steel test piece are completely dry, weigh it and record the mass as m1. Calculate the mass difference Δm1(m1-m0) of the test piece before and after the test to obtain the amount of metal oxide deposited on the surface of the test piece.

[0078] Then, a comparative experiment was conducted:

[0079] Take a stainless steel test piece (10cm long, 6cm wide, and 0.5cm high) and weigh it to obtain its mass m0. Place the stainless steel test piece into an acrylic container (15cm high and 10cm in diameter) and tilt it at an angle of 50°. Add 1L of deionized water and detergent to a 1L beaker (the volume ratio of detergent to deionized water is 1:100), and then add 0.5g of iron oxide powder (commercially available).

[0080] Stir with a glass rod to evenly disperse the iron oxide powder in the solution;

[0081] Pour the solution containing iron oxide powder into an acrylic container containing the test piece, let it stand for 10 minutes, and then drain the solution from the drain pipe at the bottom of the acrylic container.

[0082] Take out the stainless steel test piece and place it horizontally. After the residual water and sediment on the surface of the stainless steel test piece are completely dry, weigh it and record the mass as m3.

[0083] Repeat the experiment with other conditions unchanged, adjust the volume ratio of detergent to deionized water to 2:100, weigh the sample after drying and record the mass as m4. The amount of iron oxide powder deposited on the sample surface is obtained by calculating the mass difference Δm2(m3-m2) and Δm3(m4-m2) before and after the experiment.

[0084] Compare Δm1, Δm2, and Δm3 to use as the basis for evaluating the detergency of detergent A.

[0085]

[0086] In summary, this invention provides a method for testing and evaluating the decontamination performance of foam detergents in reactor pools. This method closely approximates the actual operating conditions of foam detergents, and the testing apparatus has a simple structure, making it suitable for performance evaluation during the development of foam detergents for pressurized water reactor nuclear power plants.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for testing and evaluating the decontamination performance of a foam decontaminant in a reactor pool, characterized in that, Metal oxides are added to a solution containing demineralized water and foam detergent to obtain an aqueous solution. A stainless steel test piece is immersed in the aqueous solution and stirred using the stainless steel test piece. The stainless steel test piece is then placed at an angle in the aqueous solution and allowed to stand. After standing, the aqueous solution is drained, the stainless steel test piece is removed and placed horizontally. The surface quality of the stainless steel test piece is compared to obtain the amount of metal oxide deposited on the surface of the test piece. The effects of different foam detergents on the amount of metal oxide deposited on the surface of the stainless steel test piece are compared to achieve the evaluation of the detergency performance test.

2. The method for testing and evaluating the decontamination performance of reactor pool foam detergent according to claim 1, characterized in that, The volume ratio of demineralized water to foam detergent in the solution is 1:(100-10).

3. The method for testing and evaluating the decontamination performance of reactor pool foam detergent according to claim 1, characterized in that, The metal oxide is one or more of the following: iron(II,III) oxide, cobalt(II) oxide, and nickel(II) oxide.

4. The method for testing and evaluating the decontamination performance of reactor pool foam detergent according to claim 1, characterized in that, The stirring time for the aqueous solution using a stainless steel test piece is 30 seconds to 1 minute.

5. The method for testing and evaluating the decontamination performance of reactor pool foam detergent according to claim 1, characterized in that, The stainless steel test piece was placed at an angle of 45° to 60°.

6. The method for testing and evaluating the decontamination performance of reactor pool foam detergent according to claim 1, characterized in that, The settling time is 2 to 5 minutes.

7. The method for testing and evaluating the decontamination performance of reactor pool foam detergent according to claim 1, characterized in that, After the residual water on the surface of the stainless steel test piece has dried, the surface quality of the stainless steel test piece is compared.

8. The method for testing and evaluating the decontamination performance of reactor pool foam detergent according to claim 1, characterized in that, The aqueous solution is placed in an plexiglass container.

9. The method for testing and evaluating the decontamination performance of reactor pool foam detergent according to claim 8, characterized in that, Acrylic glass containers have a cylindrical structure.

10. The method for testing and evaluating the decontamination performance of reactor pool foam detergent according to claim 1, characterized in that, The stainless steel specimen was weighed using an electronic analytical balance with an accuracy of 0.1 mg.

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