Application of a water-based lubricant on the surface of nuclear fuel rods

Abstract

The present invention provides an application of a water-based lubricant on the surface of a nuclear fuel rod, and relates to the technical field of nuclear fuel rod assembly. The application provided by the present invention comprises assembling a nuclear fuel rod with a water-based lubricant attached to the surface on a positioning grid, and then washing away the water-based lubricant; the water-based lubricant comprises isononanoic acid diethanolamide and isononanoic acid diisopropanolamide. When the nuclear fuel rod is installed on the positioning grid, the present invention improves the lubricity and protects the surface of the nuclear fuel rod cladding, thereby reducing the scratches on the nuclear fuel rod caused by the positioning grid.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear fuel rod assembly, and in particular to the application of a water-based lubricant on the surface of a nuclear fuel rod. Background Art

[0002] Nuclear energy is a clean energy released from the nucleus through nuclear reactions. It has the advantages of high energy efficiency and large energy capacity. A small amount of nuclear fuel can produce a large amount of energy. Compared with fossil fuels, nuclear energy has higher energy production capacity and is more environmentally friendly. Therefore, the extensive use of nuclear energy is not only the best choice for coping with energy crises and reducing environmental pollution, but also can replace traditional fossil fuels, thereby reducing dependence on imported fossil fuels.

[0003] At present, when nuclear fuel is used for nuclear energy, radioactive nuclear fuel is usually placed in zirconium alloy cladding to assemble into nuclear fuel rods. After the nuclear fuel rods are assembled with the spacer grid, they are arranged in the core area of ​​the nuclear reactor to form fuel assemblies. During the operation of the reactor, neutrons react with the nuclear fuel in the nuclear fuel rods to produce fission, releasing a large amount of energy. This energy is used to heat water to generate steam and then drive turbines and generators to generate electricity. Therefore, the zirconium alloy cladding is the first barrier between the nuclear fuel rods and the environment. It can seal the nuclear fuel inside and prevent radioactive substances from leaking into the external environment. It plays an important role in ensuring the safe operation of the reactor.

[0004] However, when installing the nuclear fuel rods on the spacer grid, the zirconium alloy cladding is prone to rubbing against the guide wings and spring sheets on the spacer grid, resulting in a large number of scratches and debris on the surface of the zirconium alloy cladding, and the debris will also cause secondary damage to the cladding surface, ultimately resulting in a large number of scratch defects on the cladding surface. During the use of the nuclear fuel rods, a large amount of charge will accumulate at these surface defects, causing severe electrochemical corrosion, affecting the safety of the nuclear reactor.

[0005] In the prior art, when assembling nuclear fuel rods and spacer grids, clean water is usually used for lubrication. However, the lubrication effect of clean water is insufficient and does not provide sufficient protection. After the installation is completed, a large number of scratches will still appear on the surface. Therefore, it is urgent to provide a solution to improve the above problem. Summary of the invention

[0006] The purpose of the present invention is to provide an application of a water-based lubricant on the surface of a nuclear fuel rod. By using the water-based lubricant to adhere to the surface of the cladding material of the nuclear fuel rod, the lubrication is improved and the surface of the cladding of the nuclear fuel rod is protected when the nuclear fuel rod is installed with a spacer grid, thereby reducing the scratches on the nuclear fuel rod caused by the spacer grid.

[0007] In a first aspect, the present invention provides an application of a water-based lubricant on the surface of a nuclear fuel rod. After assembling the nuclear fuel rod with the water-based lubricant attached to the surface on a positioning grid, the water-based lubricant is washed away; the water-based lubricant includes isononanoic acid diethanolamide and isononanoic acid diisopropanolamide.

[0008] The present invention can improve the lubrication performance of the surface of the nuclear fuel rod by attaching the water-based lubricant to the surface of the nuclear fuel rod, which is beneficial to improving the convenience of installing the nuclear fuel rod and the positioning grid. It can also protect the surface of the nuclear fuel rod during the installation process to prevent the positioning grid from scratching the surface of the nuclear fuel rod.

[0009] Optionally, when assembling the nuclear fuel rod with the water-based lubricant attached to the surface and the spacer grid, the thickness of the water-based lubricant attached to the surface of the nuclear fuel rod is 0.3 mm-0.4 mm.

[0010] Optionally, the amount of the aqueous lubricant attached to the surface of the nuclear fuel rod is 0.4 g / cm 2 -0.5g / cm 2 .

[0011] Optionally, flushing and removing the aqueous lubricant includes: flushing the aqueous lubricant on the surface of the nuclear fuel rod with a cleaning liquid; the cleaning liquid includes at least one of deionized water, alkaline liquid, and organic solvent.

[0012] Optionally, when the water-based lubricant on the surface of the nuclear fuel rod is flushed with a cleaning liquid, the temperature of the cleaning liquid is 30-50°C.

[0013] Optionally, before assembling the nuclear fuel rods with the water-based lubricant attached to the surface on the spacer grid, the water-based lubricant is dip-coated, rolled or brushed on the surface of the nuclear fuel rods.

[0014] Optionally, the aqueous lubricant includes a mixture of diethanolamine, diisopropanolamine, methyl hypochlorite, methyl 7-methyloctanoate and cetyltrimethylammonium bromide; the mixture includes the isononanoic acid diethanolamide and the isononanoic acid diisopropanolamide.

[0015] Optionally, the preparation method of the water-based lubricant comprises the following steps: in an ammonia-ammonium bromide buffer system, diethanolamine, diisopropanolamine and methyl hypochlorite are mixed to react to obtain an intermediate, the intermediate is mixed with methyl 7-methyloctanoate and hexadecyltrimethylammonium bromide to react, and then impurities are removed to obtain the water-based lubricant.

[0016] In a second aspect, the present invention provides a method for preparing a water-based lubricant, comprising: mixing diethanolamine, diisopropanolamine and methyl hypochlorite in an ammonia-ammonium bromide buffer system to obtain an intermediate, mixing the intermediate with methyl 7-methyloctanoate and hexadecyltrimethylammonium bromide, and removing impurities to obtain a water-based lubricant.

[0017] The preparation method provided by the present invention comprises adding methyl hypochlorite into an ammonia-ammonium bromide buffer system, which can convert the hydroxyl groups on diethanolamine and diisopropanolamine into ether bonds, and can effectively improve the conversion rate of the effective ingredients in the water-based lubricant. In addition, the lubricating performance of the water-based lubricant can be improved, and hexadecyltrimethylammonium bromide can promote aminolysis and inhibit hydrolysis in the system, thereby promoting the generation of the water-based lubricant.

[0018] Optionally, the mass ratio of the diethanolamine to the diisopropanolamine is (4-6):1.

[0019] Optionally, the mass ratio of the diethanolamine to the methyl hypochlorite is (2-3):8.

[0020] Optionally, the mass ratio of the diisopropanolamine to the methyl hypochlorite is 1:(14-18).

[0021] Optionally, the mass ratio of the diethanolamine to the methyl 7-methyloctanoate is (1-1.5):1.

[0022] Optionally, the mass ratio of the diisopropanolamine to the methyl 7-methyloctanoate is 1:(3-5).

[0023] Optionally, the mass ratio of the hexadecyltrimethylammonium bromide to the reaction mixture is 3:(900-1100), and the reaction mixture is a mixture of diethanolamine, diisopropanolamine, methyl hypochlorite and methyl 7-methyloctanoate.

[0024] Optionally, in an ammonia-ammonium bromide buffer system, the process of preparing an intermediate by mixing diethanolamine, diisopropanolamine and methyl hypochlorite for reaction comprises: adding diethanolamine, diisopropanolamine and methyl hypochlorite into the ammonia-ammonium bromide buffer system to prepare a reaction system; and reacting the reaction system at 50° C.-60° C. for 1-2 hours to prepare the intermediate.

[0025] Optionally, the pH of the ammonia-ammonium bromide buffer system is 7-8.9.

[0026] Optionally, the process of mixing the intermediate with methyl 7-methyloctanoate and cetyltrimethylammonium bromide for reaction comprises: adding methyl 7-methyloctanoate and cetyltrimethylammonium bromide into the intermediate, mixing, and reacting at 120° C.-140° C. for 5 h-7 h.

[0027] Optionally, the process of removing impurities to obtain the water-based lubricant includes: after removing water during the mixing reaction, adding an adsorption material, stirring and mixing, and then separating to obtain the water-based lubricant.

[0028] In a third aspect, the present invention also provides an aqueous lubricant prepared by any of the above optional preparation methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A flowchart of the method for preparing the aqueous lubricant provided by the present invention;

[0030] Figure 2 This is the infrared spectrum of the aqueous lubricant prepared in Example 1 of the present invention;

[0031] Figure 3 A photo of the surface of a zirconium alloy sheet after corrosion testing of the zirconium alloy sheet using the aqueous lubricant prepared in Example 1 of the present invention;

[0032] Figure 4 This is a graph showing the change in friction coefficient of Example 1, Comparative Example 1, Comparative Example 4, Comparative Example 5 and a control group when performing a lubrication performance test;

[0033] Figure 5 This is a photo of the surface scratches on the zirconium alloy cladding after Example 1 of the present invention and clean water are respectively attached to the surface of the zirconium alloy cladding and installed on the spacer grid. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be understood by people with general skills in the field to which the present invention belongs. "Including" and similar words used in this article mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0035] The present invention provides an application of a water-based lubricant on the surface of a nuclear fuel rod, by assembling a nuclear fuel rod with a water-based lubricant attached to the surface on a positioning grid, and flushing to remove the water-based lubricant. The water-based lubricant can effectively improve the surface lubricity on the surface of the nuclear fuel rod, and can also protect the surface of the nuclear fuel rod, thereby preventing the positioning grid from scratching the surface of the nuclear fuel rod during the installation of the nuclear fuel rod and the positioning grid. In addition, the water-based lubricant can be removed by flushing, thereby preventing the water-based lubricant from affecting the reaction environment of the nuclear reactor.

[0036] In some embodiments, when the nuclear fuel rod with the water-based lubricant attached to the surface is assembled with the spacer grid, the thickness of the water-based lubricant attached to the surface of the nuclear fuel rod is 0.3 mm-0.4 mm. In other embodiments, the amount of the water-based lubricant attached to the surface of the nuclear fuel rod is 0.4 g / cm 2 -0.5g / cm 2 In fact, when the amount of water-based lubricant used on the nuclear fuel rod reaches the minimum, it can play a good lubricating and protective effect. However, in order to achieve a better protective effect, the application of water-based lubricants can be limitedly increased, but the amount of water-based lubricants cannot be expanded indefinitely, because the tension of the oily water-based lubricant on the surface of the nuclear fuel rod is not enough to support the unlimited expansion of the amount of water-based lubricants.

[0037] In fact, before assembling the nuclear fuel rods with the water-based lubricant attached to the surface and the spacer grid, the water-based lubricant is attached to the surface of the nuclear fuel rods by dipping, rolling or brushing. In fact, the present invention does not limit the attachment method of the water-based lubricant, but it is necessary to be able to attach the water-based lubricant to the surface of the nuclear fuel rods.

[0038] In fact, the nuclear fuel rod includes a cladding material and nuclear fuel located inside the cladding material, and the aqueous lubricant is attached to the outer surface of the cladding material, thereby playing a lubricating and protective role on the cladding material. Specifically, the commonly used cladding material mainly includes zirconium alloy material.

[0039] In some embodiments, after the nuclear fuel rods and the spacer grids are assembled, a cleaning liquid can be used to clean the water-based lubricant on the surface of the nuclear fuel rods to improve the cleaning degree of the surface of the nuclear fuel rods and the spacer grids and avoid affecting the internal environment of the nuclear reactor. Specifically, the cleaning liquid can be at least one of deionized water, alkaline liquid, and organic solvent.

[0040] In fact, when deionized water is used to rinse the aqueous lubricant, the temperature of the cleaning liquid during the rinsing process may be 30° C.-50° C. In fact, the higher the temperature of the deionized water, the easier it is to rinse and remove the aqueous lubricant.

[0041] The invention provides a method for preparing a water-based lubricant. The method comprises the following steps: in an ammonia-ammonium bromide buffer system, diethanolamine, diisopropanolamine and methyl hypochlorite are mixed to obtain an intermediate; the intermediate is then mixed with methyl 7-methyloctanoate and hexadecyltrimethylammonium bromide, and then impurities are removed to obtain the water-based lubricant.

[0042] Specifically, when diethanolamine, diisopropanolamine and methyl hypochlorite are mixed, methyl hypochlorite can replace the hydroxyl groups in diethanolamine and diisopropanolamine with ether bonds, thereby generating bis(2-(methylperoxy)ethyl)amine and bis(2-(methylperoxy)propyl)amine. The reaction formula during the reaction is as follows:

[0043]

[0044] Specifically, the intermediate and 7-methyloctanoic acid methyl ester, under the catalytic action of hexadecyltrimethylammonium bromide, the amino groups in bis(2-(methylperoxy)ethyl)amine and bis(2-(methylperoxy)propyl)amine and the ester group in 7-methyloctanoic acid methyl ester undergo an aminolysis reaction, thereby generating 7-methyl-N,N-bis(2-(methylperoxy)ethyl)octanamide and 7-methyl-N,N-bis(2-(methylperoxy)propyl)octanamide. The reaction formula during the reaction is as follows:

[0045]

[0046] In fact, since diethanolamine and diisopropanolamine contain a large number of hydroxyl groups after mixing, and their nucleophilic activity is greater than that of amino groups, methyl hypochlorite is used to replace the hydroxyl groups with ether bonds, which can play a good protective role on the hydroxyl groups, thereby avoiding the reaction of the hydroxyl groups in diethanolamine and diisopropanolamine with the ester group of 7-methyloctanoic acid methyl ester to generate by-products, which can effectively improve the product yield.

[0047] In addition, since the ether bond is unstable, it is easy to undergo hydrolysis reaction to reduce to hydroxyl group, and hexadecyltrimethylammonium bromide can not only promote the occurrence of aminolysis reaction in the system, but also inhibit the hydrolysis of ether bond, thereby improving the protection ability of hydroxyl group. After obtaining 7-methyl-N, N-bis(2-(methylperoxide)ethyl)octanamide and 7-methyl-N, N-bis(2-(methylperoxide)propyl)octanamide, the hydrolysis reaction is promoted by removing impurities, thereby obtaining isononanoic acid diethanolamide (N, N-bis(2-hydroxyethyl)-7-methyloctanamide) and isononanoic acid diisopropanolamide (N, N-bis(2-hydroxypropyl)-7-methyloctanamide), and the reaction formula is as follows:

[0048]

[0049] In some embodiments, see Figure 1 The preparation method of the aqueous lubricant provided by the present invention comprises the following steps:

[0050] S1, adding diethanolamine and diisopropanolamine into an ammonia-ammonium bromide buffer system and stirring to obtain a mixed reaction liquid;

[0051] S2, adding methyl hypochlorite into the mixed reaction solution and mixing for reaction to obtain an intermediate;

[0052] S3, methyl 7-methyloctanoate and hexadecyltrimethylammonium bromide are mixed and added to the intermediate, and the mixture is stirred for reaction and then impurities are removed to obtain a water-based lubricant.

[0053] In some embodiments, when performing step S1, the mass ratio of diethanolamine to diisopropanolamine is (4-6): 1. In fact, by adjusting the usage of diethanolamine and diisopropanolamine, the ratio of isononanoic acid diethanolamide to isononanoic acid diisopropanolamide in the final water-based lubricant can be adjusted, and a water-based lubricant with better lubrication performance can be obtained.

[0054] In fact, the ammonia-ammonium bromide buffer system used in performing step S1 can be prepared in the laboratory in the following manner: ammonium bromide is stirred and dissolved in deionized water at 50-60° C. to obtain a saturated ammonium bromide solution; while stirring, concentrated ammonia water is added dropwise into the saturated ammonium bromide solution; and the pH of the system is adjusted to 7-8.9 to obtain the ammonia-ammonium bromide buffer system.

[0055] In fact, when preparing the ammonia-ammonium bromide buffer system, brown ammonium bromide will precipitate as concentrated ammonia water is added. This is because ammonia water reacts with ammonium bromide to generate ammonia gas and hydrobromic acid, and ammonia gas dissolves in the solution to form an ammonia-ammonium bromide buffer system.

[0056] Specifically, deionized water may be added to the buffer system when executing step S1.

[0057] In some embodiments, after performing step S2, the mass ratio of diethanolamine to methyl hypochlorite is (2-3):8.

[0058] In some embodiments, when performing step S2, the mass ratio of diisopropanolamine to methyl hypochlorite is 1:16.

[0059] Specifically, when executing step S2, methyl hypochlorite can be prepared into a methyl hypochlorite solution using methanol in advance, and the methyl hypochlorite solution is added dropwise to the intermediate under stirring. More specifically, when executing step S2, the following sub-steps are included:

[0060] S21, at 50-60° C. with stirring, adding the methyl hypochlorite solution dropwise into the mixed reaction solution to obtain a reaction system after the addition is completed;

[0061] S22, keeping the reaction system warm for 1-3 hours to obtain an intermediate.

[0062] In fact, when executing step S21, the dripping time of methyl hypochlorite is controlled to be 1-2 hours.

[0063] In fact, when executing step S21, the mixed reaction liquid is stirred at a rotation speed of 100-200 rpm.

[0064] In some embodiments, when performing step S3, the mass ratio of diethanolamine to methyl 7-methyloctanoate is (1-1.5):1.

[0065] In some embodiments, when performing step S3, the mass ratio of diisopropanolamine to methyl 7-methyloctanoate is 1:4.

[0066] In some embodiments, the mass ratio of hexadecyltrimethylammonium bromide to the reaction mixture is 3:1000, wherein the reaction mixture is a mixture of diethanolamine, diisopropanolamine, methyl hypochlorite and methyl 7-methyloctanoate.

[0067] Specifically, when executing step S3, 7-methyloctanoic acid methyl ester can be prepared into 7-methyloctanoic acid methyl ester solution using methanol in advance. More specifically, when executing step S3, the following sub-steps are included:

[0068] S31, stirring and mixing the methyl 7-methyloctanoate solution and hexadecyltrimethylammonium bromide to prepare a mixed solution;

[0069] S32, at 120-140°C, add the intermediate dropwise into the mixed solution, stir for reaction, and then keep warm, and remove impurities to obtain a water-based lubricant.

[0070] In some embodiments, when executing step S32, the duration of adding the intermediate is controlled to be 4-5 hours, and the duration of keeping warm is controlled to be 1-2 hours.

[0071] In fact, in the process of performing impurity removal in step S32, water can be removed when the intermediate is dripped into the mixed solution, which is beneficial to the hydrolysis of ether bonds in 7-methyl-N, N-bis(2-(methylperoxide)ethyl)octanamide and 7-methyl-N, N-bis(2-(methylperoxide)propyl)octanamide to form hydroxyl groups. In addition, after the addition is completed, methanol can be removed by distillation, and adsorption materials such as activated carbon can be added to remove impurity ions, and finally filtration is performed to obtain a water-based lubricant.

[0072] The present invention also provides an aqueous lubricant prepared by the preparation method provided in any of the above embodiments, comprising a mixture of diethanolamine, diisopropanolamine, methyl hypochlorite, methyl 7-methyloctanoate and hexadecyltrimethylammonium bromide.

[0073] Specifically, the aqueous lubricant includes isononanoic acid diethanolamide and isononanoic acid diisopropanolamide.

[0074] Specifically, the structural formula of isononanoic acid diethanolamide is:

[0075]

[0076] Specifically, the structural formula of isononanoic acid diisopropanolamide is:

[0077]

[0078] In addition, the present invention also provides an application of an aqueous lubricant prepared by the preparation method provided in any of the above embodiments on the surface of a nuclear fuel rod, comprising the following steps: coating the aqueous lubricant on the surface of a zirconium alloy cladding to be installed, assembling the zirconium alloy cladding with a positioning grid, and then rinsing the surface of the zirconium alloy cladding with clean water for cleaning.

[0079] Preparation Example 1

[0080] Preparation Example 1 of the present invention provides a preparation method of an ammonia-ammonium bromide buffer system, comprising the following steps: after stirring and dissolving ammonium bromide in 50°C deionized water to prepare a saturated aqueous solution of ammonium bromide, under low-speed stirring of 10-20rpm, adding concentrated ammonia water dropwise into the saturated aqueous solution of ammonium bromide, and adjusting the pH to 8.9 to obtain the ammonia-ammonium bromide buffer system.

[0081] Example 1

[0082] Embodiment 1 of the present invention provides a method for preparing a water-based lubricant, comprising the following steps:

[0083] S1. After adding 200 mL of the ammonia-ammonium bromide buffer system prepared in Preparation Example 1 into a three-necked flask, 50.00 g of diethanolamine, 10.00 g of diisopropanolamine and 130.00 g of deionized water were added into the buffer system and stirred and mixed in a 60° C. water bath to obtain a mixed reaction liquid;

[0084] S2, 157.00g of methyl hypochlorite was stirred and dissolved in 200.00g of methanol to obtain a methyl hypochlorite solution, and the methyl hypochlorite solution was charged into a dropping funnel and assembled on a three-necked flask, the three-necked flask was placed in a 50°C water bath, and the methyl hypochlorite solution was slowly dripped at a speed of 150rpm, the total dripping time was controlled to be 1.5h, and the three-necked flask was kept warm for 1h after the dripping to obtain an intermediate;

[0085] S3. After 160.00 g of 7-methyloctanoate is stirred and dissolved in 200.00 g of methanol to obtain a 7-methyloctanoate solution, the 7-methyloctanoate solution is charged into a four-necked flask, and 2.6 g of hexadecyltrimethylammonium bromide is added to obtain a mixed solution. A mechanical stirrer, a thermometer, a condenser and a constant pressure dropping funnel are assembled, and the four-necked flask is placed in a 120° C. water bath; the intermediate is added into the constant pressure dropping funnel, and the intermediate is added dropwise into the mixed solution at a rotation speed of 200 rpm, and the total duration of the dropping is controlled to be 4 h. After the dropping is completed, the mixture is kept warm for 1 h. After the methanol is removed by rectification, activated carbon is added, and the mixture is kept warm at 50° C. for 2 h, and filtered and separated to obtain an oily aqueous lubricant.

[0086] The aqueous lubricant prepared in Example 1 was tested by infrared spectrum. Figure 2 shown.

[0087] Example 2

[0088] Embodiment 2 of the present invention provides a method for preparing a water-based lubricant, comprising the following steps:

[0089] S1. After adding 200 mL of the ammonia-ammonium bromide buffer system prepared in Preparation Example 1 into a three-necked flask, 53.00 g of diethanolamine, 15.00 g of diisopropanolamine and 130.00 g of deionized water were added into the buffer system and stirred to obtain a mixed reaction solution;

[0090] S2, 160.00g of methyl hypochlorite was stirred and dissolved in 200.00g of methanol to obtain a methyl hypochlorite solution, and the methyl hypochlorite solution was charged into a dropping funnel and assembled on a three-necked flask, the three-necked flask was placed in a 60°C water bath, and the methyl hypochlorite solution was slowly dripped into it at a speed of 150rpm, the total dripping time was controlled to be 2h, and the three-necked flask was kept warm for 1h after the dripping to obtain an intermediate;

[0091] S3. After 165.00 g of 7-methyloctanoate is stirred and dissolved in 200.00 g of methanol to obtain a 7-methyloctanoate solution, the 7-methyloctanoate solution is charged into a four-necked flask, and 2.8 g of hexadecyltrimethylammonium bromide is added to obtain a mixed solution. A mechanical stirrer, a thermometer, a condenser and a constant pressure dropping funnel are assembled, and the four-necked flask is placed in a 140° C. water bath; the intermediate is added into the constant pressure dropping funnel, and the intermediate is added dropwise into the mixed solution at a rotation speed of 200 rpm, and the total duration of the dropping is controlled to be 5 h. After the dropping is completed, the mixture is kept warm for 1 h. After the methanol is removed by rectification, activated carbon is added, and the mixture is kept warm at 60° C. for 2 h, and filtered and separated to obtain an aqueous lubricant in a pure oily state.

[0092] Comparative Example 1

[0093] This comparative example 1 provides a method for preparing a water-based lubricant, comprising the following steps:

[0094] D1, 50.00 g of diethanolamine, 10.00 g of diisopropanolamine and 0.4 g of 1 8-crown ether-6 were added to 165.00 g of isononanoic acid to prepare a reaction mixture;

[0095] D3. Stir the reaction mixture at 120°C for 4 hours, start the vacuum pump to drain water, and then filter and separate to obtain the aqueous lubricant.

[0096] Comparative Example 2

[0097] Comparative Example 2 provides a method for preparing an aqueous lubricant, which is different from Example 1 in that, in step S3, after the 7-methyloctanoate solution is charged into a four-necked flask, 2.8 g of calcium sulfate is added to prepare a mixed solution, and the aqueous lubricant prepared in step S3 is not in a pure oily state.

[0098] Comparative Example 3

[0099] This comparative example 3 provides a method for preparing a water-based lubricant, which is different from Example 1 in that step S2 is not performed, and when step S3 is performed, the mixed reaction liquid is added dropwise into the mixed solution, and the form of the water-based lubricant prepared in step S3 is not pure oil.

[0100] Performance testing:

[0101] Based on the corrosion test method described in GB6144-2010 Synthetic Cutting Fluid, the corrosion performance test of the water-based lubricant prepared in the above Example 1 is carried out, comprising the following steps:

[0102] C1. The aqueous lubricant and deionized water were mixed and diluted in a mass ratio of 1:9 to obtain an experimental group, and an equal amount of deionized water as the experimental group was used as a control group;

[0103] C2. After cleaning and drying the surface of the zirconium alloy sheet with anhydrous ethanol, polish the surface of the zirconium alloy sheet with 400-grit sandpaper to ensure that at least one plane on the surface of the zirconium alloy has no pits, scratches, or rust, and use this plane as the plane to be tested;

[0104] C3. Immerse the zirconium alloy sheets in the experimental group and the control group respectively, and place them in a constant temperature box at 55°C for 8 hours. Then take out the zirconium alloy sheets in the experimental group and the control group, and judge the corrosion degree of the plane to be tested of the zirconium alloy sheet in the experimental group based on the corrosion standard recorded in Table 1 below and the corrosion condition of the plane to be tested of the zirconium alloy sheet in the control group.

[0105] Table 1 Corrosion performance evaluation criteria

[0106] Rust-free, shiny as new Level A Slight discoloration Class B Moderate discoloration C-Class Severe discoloration D-Class

[0107] After evaluation, the zirconium alloy sheets that were kept at 55°C for 8 hours were taken out from the experimental group. The surface was rust-free and shiny as new. Figure 3 As shown, it reaches Class A, which indicates that the aqueous lubricant prepared by the present invention has no corrosive ability to zirconium alloy materials and can be well applied on the surface of zirconium alloys.

[0108] A graphene aqueous solution with a mass fraction of 1% was configured as comparative example 4, a castor oil aqueous solution with a mass fraction of 1% was configured as comparative example 5, and deionized water was selected as a control group. The lubrication performance of Example 1, comparative example 1, comparative example 4, comparative example 5 and the control group was tested using an HSR-2M reciprocating friction and wear tester under the conditions of a load of 30g, a running speed of 10T / min, and a reciprocating length of 3mm. The test results are shown in FIG. Figure 4 shown.

[0109] from Figure 4 It can be seen that the aqueous lubricant prepared in Example 1 has a low and stable friction coefficient of 0.09, which indicates that the aqueous lubricant prepared in Example 1 has good lubrication performance, while the friction coefficient of the aqueous lubricant prepared in Comparative Example 1 is 0.22, which indicates that a reaction between hydroxyl groups and ester groups occurs in Comparative Example 1, thereby causing the lubrication performance of the aqueous lubricant to decrease.

[0110] It can be seen from Example 1 to Example 2 and Comparative Example 2 to Comparative Example 3 that, since calcium sulfate is used as a catalyst to promote the aminolysis reaction in Comparative Example 2, it is difficult to inhibit the hydrolysis of ether bonds, resulting in the hydrolysis of ether bonds in part of 7-methyl-N, N-bis(2-(methylperoxy)ethyl)octanamide and part of 7-methyl-N, N-bis(2-(methylperoxy)propyl)octanamide to hydroxyl groups, which in turn leads to the generation of a large number of by-products, thereby reducing the content of the effective ingredient in the aqueous lubricant. In Comparative Example 3, since the nucleophilic activity of the hydroxyl group is greater than that of the amino group, the side reaction of substitution between the amino group in the mixture of diethanolamine and diisopropanolamine and the ester group of 7-methyloctanoic acid methyl ester is more likely to occur in the mixture, resulting in a large amount of by-products in the final product.

[0111] The aqueous lubricant prepared in Example 1 was dip-coated on the surface of a cylindrical zirconium alloy cladding with a length of 400 cm and a diameter of 1 cm. The zirconium alloy cladding material was then assembled on a positioning grid. After the assembly was completed, the aqueous lubricant was removed by washing with clean water. The scratches on the zirconium alloy surface cladding were observed using a metallographic microscope and the scratch width was measured ( Figure 5 (B)); Use clean water as a lubricant to wet the surface of the zirconium alloy cladding, assemble it on a spacer grid, observe the surface scratches and measure the scratch width ( Figure 5 (A)); The scratch measurement results are shown in Table 2 below, and the surface Figure 5 shown.

[0112] Table 2 Scratch measurement results

[0113] Scratch width (μm) Example 1 128 Shimizu 648

[0114] from Figure 5 It can be seen that the aqueous lubricant prepared in Example 1 of the present invention can play a good protective role on the surface of the zirconium alloy cladding.

[0115] Although the embodiments of the present invention are described in detail above, it is obvious to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention as described in the claims. Moreover, the present invention described herein may have other embodiments and may be implemented or realized in a variety of ways.

Claims

1. Application of a water-based lubricant on the surface of a nuclear fuel rod, characterized in that: The nuclear fuel rods with water-based lubricants attached to the surfaces are assembled on a positioning grid, and the water-based lubricants are washed and removed; the water-based lubricants include isononanoic acid diethanolamide and isononanoic acid diisopropanolamide, and the preparation method of the water-based lubricants comprises the following steps: adding diethanolamine, diisopropanolamine and methyl hypochlorite into an ammonia-ammonium bromide buffer system to prepare a reaction system; reacting the reaction system at 50-60° C. for 1-2 hours to prepare an intermediate; mixing the intermediate with 7-methyloctanoic acid methyl ester and hexadecyltrimethylammonium bromide for reaction, and removing impurities to prepare the water-based lubricant.

2. The use according to claim 1, characterized in that: When the nuclear fuel rod with the water-based lubricant attached to the surface is assembled with the spacer grid, the thickness of the water-based lubricant attached to the surface of the nuclear fuel rod is 0.3 mm-0.4 mm.

3. The use according to claim 1, characterized in that: When a nuclear fuel rod with a water-based lubricant attached to its surface is assembled with a spacer grid, the amount of the water-based lubricant attached to the surface of the nuclear fuel rod is 0.4 g / cm 2 -0.5g / cm 2 .

4. The use according to claim 1, characterized in that: Flushing and removing the aqueous lubricant includes: using a cleaning liquid to flush the aqueous lubricant on the surface of the nuclear fuel rod; the cleaning liquid includes deionized water.

5. The use according to claim 4, characterized in that: When the water-based lubricant on the surface of the nuclear fuel rod is flushed with a cleaning liquid, the temperature of the cleaning liquid is 30°C-50°C.

6. The use according to claim 1, characterized in that: Before assembling the nuclear fuel rods with the water-based lubricant attached to the surface on the spacer grid, the water-based lubricant is dip-coated, rolled or brushed on the surface of the nuclear fuel rods.

7. The use according to claim 1, characterized in that: The mass ratio of the diethanolamine to the diisopropanolamine is (4-6):

1.

8. The use according to claim 1, characterized in that: The mass ratio of the diethanolamine to the methyl hypochlorite is (2-3):

8.

9. The use according to claim 1, characterized in that: The mass ratio of the diisopropanolamine to the methyl hypochlorite is 1:(14-18).

10. The use according to claim 1, characterized in that: The mass ratio of the diethanolamine to the methyl 7-methyloctanoate is (1-1.5):

1.

11. The use according to claim 1, characterized in that: The mass ratio of the diisopropanolamine to the methyl 7-methyloctanoate is 1:(3-5).

12. The use according to claim 1, characterized in that: The mass ratio of the hexadecyltrimethylammonium bromide to the reaction mixture is 3:(900-1100), and the reaction mixture is a mixture of diethanolamine, diisopropanolamine, methyl hypochlorite and methyl 7-methyloctanoate.

13. The use according to claim 1, characterized in that: The pH of the ammonia-ammonium bromide buffer system is 7-8.

9.

14. The use according to claim 1 or 13, characterized in that: The structural formula of the isononanoic acid diethanolamide is: ； And / or, the structural formula of the isononanoic acid diisopropanolamide is: 。

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