Radiation resistant topcoat for nuclear power plants and preparation method and application thereof

Abstract

The application discloses a kind of nuclear power station radiation-resistant finish and its preparation method and application, belong to nuclear power coating field.The nuclear power station radiation-resistant finish of the application is made by mixing uniformly by mass ratio 5-8:1 of component A and component B;The component A includes resin, pigment and filler, mixed solvent A, additive A, additive B;The component B includes organic amine curing agent, mixed solvent B, toughening agent, additive C.The nuclear power station radiation-resistant finish of the application has excellent corrosion resistance, radiation resistance, fire resistance, radionuclide decontamination, and passes through simulation LOCA test, especially applicable to nuclear island containment, nuclear auxiliary concrete plant and steel structure equipment, meet the demand of nuclear power station.

Description

Technical Field

[0001] This invention belongs to the field of nuclear power coatings, specifically relating to a radiation-resistant topcoat for nuclear power plants, its preparation method, and its application. Background Technology

[0002] With the continuous construction of nuclear power units and the increasing power generation capacity of nuclear power plants in my country, radiation intensity is also increasing. A nuclear power unit mainly consists of three parts: the nuclear island, the conventional island, and the auxiliary systems. Different parts have different performance requirements for nuclear power plant coatings. The nuclear island is the collective term for the nuclear reactor and its systems within the containment vessel of a nuclear power plant. The nuclear island system has the highest performance requirements for coatings. The system environment contains a large amount of radioactive material and is often under high temperature and humidity conditions. Especially under loss-of-coolant conditions, the instantaneous high temperature and pressure, along with a large amount of radioactive material, create a complex environment of strong radiation and strong corrosion. Therefore, the protective coatings applied to the nuclear island must not exhibit peeling, cracking, or powdering. Otherwise, a large amount of residue will enter the reactor coolant, causing blockages in pipelines, pumps, nozzles, and cooling pipes, affecting the safe operation of the nuclear power plant system and potentially leading to serious safety accidents. Therefore, coatings used for concrete and steel structures within the containment vessel must undergo radiation resistance tests, decontamination tests, and LOCA tests. Domestically available radiation-resistant protective coatings typically pass radiation resistance and decontamination performance tests, but fail the LOCA test, thus prohibiting their use within the nuclear island containment. Alternatively, these products may only be suitable for steel structures or concrete, and there are no radiation-resistant coatings that can be used on both substrates simultaneously, limiting their application in nuclear power plant nuclear island systems. Summary of the Invention

[0003] The purpose of this invention is to address the issues of low domestic production rates of radiation-resistant coatings used in the containment concrete and steel structures of nuclear island systems, the lack of LOCA testing in existing radiation-resistant coatings, and the limitation of products to single applications on steel structures or concrete. This invention provides a radiation-resistant topcoat for nuclear power plants and its preparation method. The product formulation of this invention is 100% domestically produced, and it possesses excellent corrosion resistance, radiation protection, fire retardancy, and radionuclide decontamination properties. Furthermore, it has passed simulated LOCA testing and can be used on both steel structures and concrete substrates.

[0004] To achieve the above objectives, the present invention adopts the following technical solution.

[0005] A radiation-resistant topcoat for nuclear power plants is prepared by mixing component A and component B in a mass ratio of 5-8:1.

[0006] The A component comprises the following raw materials in parts by weight: 40-45 parts resin, 40-48 parts pigments and fillers, 8-10 parts mixed solvent A, 1-2.5 parts additive A, and 3-4.5 parts additive B;

[0007] Component B comprises the following raw materials in parts by weight: 76-85 parts of organic amine curing agent, 9-20 parts of mixed solvent B, 3-5 parts of toughening agent, and 0.8-1.3 parts of additive C.

[0008] Furthermore, the resin is one or more of phenolic epoxy resin, bisphenol A epoxy resin of different molecular weights, and organosilicon modified epoxy resin, and the resin refractive index is ≥1.62.

[0009] Furthermore, the pigments and fillers are any three or more of titanium dioxide, inorganic hybrid potassium hexatitanate whiskers, talc, barium sulfate, and mica powder, wherein the inorganic hybrid potassium hexatitanate whiskers are obtained by hybridization with inorganic silicate clay, and the inorganic silicate clay is one of montmorillonite, sepiolite, attapulgite, halloysite, and dickite.

[0010] Furthermore, the additive A is composed of an anti-settling agent, a wetting and dispersing agent, a leveling agent, an antifoaming agent, and silicone oil; the additive B is one or more of trimethylolpropane monoallyl ether, dibutyl phthalate, dioctyl phthalate, or triphenyl phosphate.

[0011] Furthermore, the mixed solvent A is one or more of xylene, butanol, isopropanol, acetone, benzyl alcohol, and solvent oil.

[0012] Furthermore, the organic amine curing agent is one or more of polyamide curing agents, modified polyamide curing agents, and aromatic amine curing agents; the mixed solvent B is one or more of xylene, toluene, butanol, isopropanol, acetone, benzyl alcohol, and solvent oil; the toughening agent is one or more of nano-calcium carbonate, nano-silica, graphene oxide, modified graphene, and carbon nanotubes; and the additive C is composed of wetting and dispersing agents, defoamers, and anti-settling agents.

[0013] The present invention also provides a method for preparing the above-mentioned radiation-resistant topcoat for nuclear power plants, comprising the following steps:

[0014] (1) Preparation of inorganic hybrid potassium hexatitanate whiskers

[0015] Potassium hexatite whiskers and inorganic silicate clay were added to a mortar and pestle at a weight ratio of 2-2.2:1. A certain amount of anhydrous ethanol was added as a dispersion medium. The mixture was ground for 2 hours at a speed of 120 rad / min and dried at 60℃ for 2 hours to obtain a precursor. The precursor was calcined at 380℃ for 2 hours, cooled naturally, ground, and sieved to obtain inorganic hybrid potassium hexatite whiskers.

[0016] (2) Preparation of component A

[0017] According to the formulation of component A, first add resin and additive B, then slowly add anti-settling agent while stirring, disperse at high speed for 10 minutes until a uniform viscous liquid is formed, then add wetting and dispersing agent and part of defoamer, and add pigments and fillers while stirring. After uniform dispersion, grind with sand mill until the fineness is less than 50μm, filter to remove grinding sand, and add leveling agent and the remaining defoamer, silicone oil and mixed solvent A. Stir evenly, filter and package for later use.

[0018] (3) Preparation of component B

[0019] According to the formulation of component B, the organic amine curing agent is mixed and dispersed evenly. While stirring, the anti-settling agent, wetting and dispersing agent and part of the defoamer are added. After high-speed dispersion for 10 minutes, the toughening agent is slowly added while stirring. After being evenly dispersed, it is ground with sand mill until the fineness is less than 50μm. The grinding sand is filtered out, and the remaining defoamer and mixed solvent B are added. The mixture is stirred evenly, filtered, packaged, and ready for use.

[0020] This invention also provides the application of the aforementioned radiation-resistant topcoat for nuclear power plants in the nuclear island containment, nuclear auxiliary concrete building, and steel structure facilities and equipment. Before construction, the prepared component A and component B are mixed evenly at a mass ratio of 5-8:1, and applied by spraying, roller coating, brushing, or other methods.

[0021] Due to the adoption of the above technical solution, the beneficial technical effects of the present invention are as follows:

[0022] 1. The radiation-resistant topcoat for nuclear power plants of the present invention has excellent radiation resistance performance at a dose rate of 2.80 Gy / s and a radiation resistance of 1×10⁻⁶ g / s. 7 Under the cumulative γ-ray irradiation dose of Gy, the coating film remained intact, without blistering, cracking, peeling, or chalking, and the adhesion after irradiation was greater than 3.4 MPa.

[0023] 2. The radiation-resistant topcoat for nuclear power plants of the present invention has excellent decontamination effect, and the paint film surface is resistant to radiation containing... 137 Cs、 90 Sr+ 90 Y has a radioactive contamination sensitivity rate of less than 9% and a decontamination rate of greater than 94%.

[0024] 3. The radiation-resistant topcoat for nuclear power plants of the present invention can pass the evaluation test (LOCA) of protective coatings for pressurized water reactor nuclear power plant facilities and equipment under simulated design baseline accident conditions in "NB / T 20133.2". After the test, the paint film is intact and there are no blistering, cracking, peeling and chalking phenomena. The adhesion of the LOCA superimposed test is greater than 1.5MPa.

[0025] 4. The radiation-resistant topcoat for nuclear power plants of the present invention contains potassium hexatitanate whiskers and inorganic silicate clay in its components. In addition to improving the radiation resistance of the coating, it also improves the heat resistance and corrosion resistance of the coating. Through the synergistic effect of the components, the final coating has the characteristics of heat resistance, corrosion resistance and radiation protection, which can meet the requirements of nuclear power plants.

[0026] 5. The radiation-resistant topcoat for nuclear power plants of the present invention optimizes the resin and combines radiation-resistant pigments, fillers, and curing agents. In the selection of key radiation-resistant fillers, heat resistance, fire retardancy, and corrosion resistance are taken into account. At the same time, the microporosity in the paint film is reduced, and the paint film cures more uniformly and densely. The resulting coating has heat resistance, corrosion resistance, and radiation protection. Meanwhile, various key toughening agents and plasticizers are optimized and added to adjust the mechanical properties of the coating. This ensures the adhesion of the coating to the substrate after γ-ray irradiation and LOCA testing, resulting in a coating material with excellent radiation resistance without sacrificing mechanical properties.

[0027] 6. The radiation-resistant topcoat for nuclear power plants of the present invention has both anti-corrosion, fireproof and radiation protection properties, and is especially suitable for use in the inner island containment building, nuclear auxiliary concrete building and steel structure equipment of nuclear power plants. It can be applied by spraying, roller coating, brushing and other methods. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0029] It should be noted that the raw materials used in the following embodiments are all industrial products for coatings.

[0030] Example 1

[0031] The radiation-resistant topcoat for nuclear power plants in this embodiment is prepared by mixing component A and component B in a mass ratio of 8:1.

[0032] Component A is composed of the following raw materials in parts by weight: 30 parts phenolic epoxy resin, 15 parts bisphenol A epoxy resin, 9 parts titanium dioxide, 16 parts inorganic hybrid potassium hexatitanate whiskers, 7 parts talc, 8 parts mica powder, 4 parts xylene, 2 parts butanol, 2 parts benzyl alcohol, 1 part anti-settling agent, 0.6 parts wetting and dispersing agent, 0.3 parts leveling agent, 0.3 parts defoamer, 0.3 parts silicone oil, and 4.5 parts trimethylolpropane monoallyl ether.

[0033] Component B is composed of the following raw materials in parts by weight: 85 parts aromatic amine curing agent, 4 parts xylene, 1 part butanol, 2 parts acetone, 2.2 parts benzyl alcohol, 5 parts nano calcium carbonate, 0.1 parts anti-settling agent, 0.4 parts wetting and dispersing agent, and 0.3 parts defoamer.

[0034] Preparation of inorganic hybrid potassium hexatitanate crystals: Accurately weigh 20g of attapulgite clay and 10g of potassium hexatitanate whiskers, add them to a mortar and pestle grinder, add 20ml of anhydrous ethanol as a dispersion medium, grind for 2h at a speed of 120rad / min, and then dry the sample at 60℃ for 2h to obtain the precursor. Calcine the precursor at 380℃ for 2h, and after natural cooling, grind and sieve to obtain inorganic hybrid potassium hexatitanate whiskers.

[0035] Preparation of Component A: According to the formulation of Component A, first add phenolic epoxy resin and trimethylolpropane monoallyl ether. Slowly add anti-settling agent while stirring. Disperse at high speed for 10 minutes until a homogeneous viscous liquid is formed. Then add wetting and dispersing agent and part of defoamer. While stirring, add titanium dioxide, inorganic hybrid potassium hexatitanate whiskers, talc powder, and mica powder. After dispersing evenly, grind with sand to a fineness of less than 50μm. Filter to remove grinding sand. Add leveling agent, silicone oil, and the remaining defoamer and mixed solvent A formed by xylene, butanol, and benzyl alcohol. Stir evenly, filter, and package for later use.

[0036] Preparation of Component B: According to the formulation of Component B, under stirring conditions, add anti-settling agent, wetting and dispersing agent and part of defoamer to aromatic amine curing agent. After high-speed dispersion for 10 min, slowly add nano calcium carbonate while stirring. After uniform dispersion, grind with sand mill to a fineness of less than 50 μm, filter to remove grinding sand, and add the remaining defoamer and mixed solvent B formed by xylene, butanol, acetone and benzyl alcohol. Stir evenly, filter and package for later use.

[0037] Before construction, the prepared component A and component B are mixed at a mass ratio of 8:1 to obtain the radiation-resistant topcoat for nuclear power plants in this embodiment.

[0038] Example 2

[0039] The radiation-resistant topcoat for nuclear power plants in this embodiment is prepared by mixing component A and component B in a mass ratio of 6:1.

[0040] Component A is composed of the following raw materials in parts by weight: 40 parts of organosilicon modified epoxy resin, 8 parts of titanium dioxide, 18 parts of inorganic hybrid potassium hexatitanate whiskers, 9 parts of talc, 2 parts of barium sulfate, 8 parts of mica powder, 6 parts of xylene, 2 parts of butanol, 2 parts of acetone, 0.8 parts of anti-settling agent, 0.6 parts of wetting and dispersing agent, 0.2 parts of leveling agent, 0.3 parts of defoamer, 0.1 parts of silicone oil, and 3 parts of dibutyl phthalate.

[0041] Component B is composed of the following raw materials in parts by weight: 80 parts modified polyamide curing agent, 10 parts xylene, 2 parts isopropanol, 2 parts solvent oil, 2 parts butanol, 3 parts nano silica, 0.4 parts wetting and dispersing agent, 0.4 parts defoamer, and 0.2 parts anti-settling agent.

[0042] Preparation of inorganic hybrid potassium hexatitanate crystals: Accurately weigh 35.7g of sepiolite and 17g of potassium hexatitanate whiskers, add them to a mortar and pestle grinder, add 35ml of anhydrous ethanol as the dispersion medium, grind for 2h at a speed of 120rad / min, and then dry the sample at 60℃ for 2h to obtain the precursor. Calcine the precursor at 380℃ for 2h, and after natural cooling, grind and sieve to obtain inorganic hybrid potassium hexatitanate whiskers.

[0043] Preparation of Component A: According to the formulation of Component A, first add organosilicon-modified epoxy resin and dibutyl phthalate, and slowly add anti-settling agent while stirring. After high-speed dispersion for 10 minutes until a homogeneous viscous liquid is formed, add wetting and dispersing agent and part of defoamer. While stirring, add titanium dioxide, inorganic hybrid potassium hexatitanate whiskers, talc powder, barium sulfate, and mica powder. After uniform dispersion, grind with sand to a fineness of less than 50μm. Filter to remove grinding sand, and add leveling agent, silicone oil, and the remaining defoamer and mixed solvent A formed by xylene, butanol, and acetone. Stir evenly, filter, package, and set aside for later use.

[0044] Preparation of Component B: According to the formulation of Component B, under stirring conditions, add anti-settling agent, wetting and dispersing agent and part of defoamer to the modified polyamide curing agent. After high-speed dispersion for 10 minutes, slowly add nano-silica while stirring. After uniform dispersion, grind with sand mill to a fineness of less than 50μm, filter to remove grinding sand, and add the remaining defoamer and mixed solvent B formed by xylene, isopropanol, solvent oil and butanol. Stir evenly, filter and package for later use.

[0045] Example 3

[0046] The radiation-resistant topcoat for nuclear power plants in this embodiment is prepared by mixing component A and component B in a mass ratio of 5:1.

[0047] Component A is composed of the following raw materials in parts by weight: 26 parts bisphenol A epoxy resin, 15 parts organosilicon modified epoxy resin, 12 parts titanium dioxide, 15 parts inorganic hybrid potassium hexatitanate whiskers, 12 parts talc, 7 parts mica powder, 2 parts barium sulfate, 4 parts xylene, 1 part butanol, 1 part acetone, 1 part benzyl alcohol, 0.1 part anti-settling agent, 0.4 parts wetting and dispersing agent, 0.1 part leveling agent, 0.3 parts defoamer, 0.1 part silicone oil, and 3 parts triphenyl phosphate.

[0048] Component B is composed of the following raw materials in parts by weight: 76 parts polyamide curing agent, 8 parts xylene, 2.5 parts butanol, 2.2 parts isopropanol, 6 parts solvent oil, 3 parts modified graphene, 0.6 parts wetting and dispersing agent, 0.3 parts defoamer, and 0.4 parts anti-settling agent.

[0049] Preparation of inorganic hybrid potassium hexatitanate crystals: Accurately weigh 33g of montmorillonite and 15g of potassium hexatitanate whiskers, add them to a mortar and pestle grinder, add 30ml of anhydrous ethanol as a dispersion medium, grind for 2h at a speed of 120rad / min, and then dry the sample at 60℃ for 2h to obtain the precursor. Calcine the precursor at 380℃ for 2h, and after natural cooling, grind and sieve to obtain inorganic hybrid potassium hexatitanate whiskers.

[0050] Preparation of Component A: According to the formulation of Component A, first add bisphenol A epoxy resin, organosilicon modified epoxy resin and triphenyl phosphate. Slowly add anti-settling agent while stirring. Disperse at high speed for 10 minutes until a uniform viscous liquid is formed. Then add wetting and dispersing agent and part of defoamer. While stirring, add titanium dioxide, inorganic hybrid potassium hexatitanate whiskers, talc powder, barium sulfate and mica powder. After uniform dispersion, grind with sand to a fineness of less than 50μm. Filter to remove grinding sand. Add leveling agent, silicone oil and the remaining defoamer and mixed solvent A formed by xylene, butanol, acetone and benzyl alcohol. Stir evenly, filter and package for later use.

[0051] Preparation of Component B: According to the formulation of Component B, under stirring conditions, add anti-settling agent, wetting and dispersing agent and part of defoamer to polyamide curing agent. After high-speed dispersion for 10 minutes, slowly add modified graphene while stirring. After uniform dispersion, grind with sand mill to a fineness of less than 50μm, filter to remove grinding sand, and add the remaining defoamer and mixed solvent B formed by xylene, butanol, isopropanol and solvent oil. Stir evenly, filter and package for later use.

[0052] Comparative Example

[0053] The radiation-resistant coating for nuclear power plants is prepared by mixing component A and component B in a mass ratio of 4:1.

[0054] Component A consists of: 50 parts epoxy resin, 6 parts phenolic resin, 13 parts titanium dioxide, 3 parts iron oxide red, 4 parts barium sulfate, 4 parts talc, 6 parts calcium carbonate, 1 part additive, 7 parts xylene, and 5 parts butanol.

[0055] Component B: 90 parts modified amine curing agent, 10 parts accelerator.

[0056] Test Example: Coating Performance Testing

[0057] 1. Preparation of test samples

[0058] The tinplate measures 12cm × 5cm × 0.02cm, and the steel plate measures 20cm × 10cm × 0.5cm, both surfaces having undergone degreasing and sandblasting treatment. The concrete block measures 20cm × 10cm × 4cm, and its surface has been cleaned, dusted, and coated with an epoxy sealing primer. At 23±2℃ and 50% relative humidity, the treated tinplate, steel plate, and concrete block were sprayed with the coatings prepared in Examples 1-3 and the comparative examples (tinplate: approximately 25μm thick, steel plate: approximately 180μm thick, concrete block: approximately 280μm thick), and after curing and drying, relevant tests were conducted.

[0059] 2. Test Results

[0060] The samples were tested according to relevant standards. The paint film of each sample was observed to be smooth, dense, and free from defects such as sagging, pinholes, etc. Other test results are listed in Table 1.

[0061] Table 1. Results of Coating Performance Testing

[0062]

[0063]

[0064] As can be seen from the test results in Table 1, the radiation-resistant topcoat film for nuclear power plants of the present invention has excellent radiation resistance, corrosion resistance, nuclear contaminant removal rate and fire resistance, and can meet the standard requirements and pass the LOCA test in the radiation environment of nuclear power plants.

[0065] The radiation-resistant topcoat for nuclear power plants of the present invention can be applied by spraying, brushing or roller coating. The construction environment is flexible, and the coating cures quickly at room temperature. The coating film is dense, smooth and hard with strong adhesion. It has excellent radiation resistance and long-term anti-corrosion effect, making it an ideal protective coating for nuclear power plants.

[0066] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A radiation-resistant topcoat for nuclear power plants, characterized in that, It is prepared by mixing component A and component B in a mass ratio of 5-8:1; The A component comprises the following raw materials in parts by weight: 40-45 parts resin, 40-48 parts pigments and fillers, 8-10 parts mixed solvent A, 1-2.5 parts additive A, and 3-4.5 parts additive B; Component B comprises the following raw materials in parts by weight: 76-85 parts organic amine curing agent, 9-20 parts mixed solvent B, 3-5 parts toughening agent, and 0.8-1.3 parts additive C; The resin is one or more of phenolic epoxy resin, bisphenol A epoxy resin, and organosilicon modified epoxy resin, and the resin refractive index is ≥1.

62. The pigments and fillers mentioned are titanium dioxide, inorganic hybrid potassium hexatitanate whiskers, talc, barium sulfate, and mica powder; The method for preparing the inorganic hybrid potassium hexatitanate whiskers is as follows: potassium hexatitanate whiskers and inorganic silicate clay are added to a mortar and pestle at a weight ratio of 2-2.2:

1. A certain amount of anhydrous ethanol is added as a dispersion medium. The mixture is ground for 2 hours at a speed of 120 rad / min. After drying at 60℃ for 2 hours, a precursor is obtained. The precursor is calcined at 380℃ for 2 hours, naturally cooled, ground, and sieved to obtain the final product. The inorganic silicate clay is one of montmorillonite, sepiolite, attapulgite, halloysite, and dickite. The toughening agent is one or more of nano-calcium carbonate, nano-silica, modified graphene, and carbon nanotubes. The aforementioned additive A is composed of an anti-settling agent, a wetting and dispersing agent, a leveling agent, a defoamer, and silicone oil. The auxiliary agent B is one or more of trimethylolpropane monoallyl ether, dibutyl phthalate, dioctyl phthalate, or triphenyl phosphate; The additive C is composed of wetting and dispersing agents, defoamers, and anti-settling agents.

2. The radiation-resistant topcoat for nuclear power plants according to claim 1, characterized in that: The mixed solvent A is one or more of xylene, butanol, isopropanol, acetone, benzyl alcohol, and solvent oil.

3. The radiation-resistant topcoat for nuclear power plants according to claim 2, characterized in that: The organic amine curing agent is one or more of polyamide curing agents, modified polyamide curing agents, and aromatic amine curing agents.

4. The radiation-resistant topcoat for nuclear power plants according to claim 3, characterized in that: The mixed solvent B is one or more of xylene, toluene, butanol, isopropanol, acetone, benzyl alcohol, and solvent oil.

5. A method for preparing a radiation-resistant topcoat for nuclear power plants as described in claim 4, characterized in that, Includes the following steps: Preparation of component A According to the formulation of component A, first add resin and auxiliary agent B, then slowly add anti-settling agent while stirring, disperse at high speed for 10 minutes until a uniform viscous liquid is formed, then add wetting and dispersing agent and part of defoamer, and add pigments and fillers while stirring. After uniform dispersion, grind with sand mill until the fineness is less than 50μm, filter to remove grinding sand, add leveling agent and the remaining defoamer and mixed solvent A, stir evenly, filter and package for later use; Preparation of component B According to the formulation of component B, the organic amine curing agent is mixed and dispersed evenly. While stirring, the anti-settling agent, wetting and dispersing agent and part of the defoamer are added. After high-speed dispersion for 10 minutes, the toughening agent is slowly added while stirring. After being evenly dispersed, it is ground with sand mill until the fineness is less than 50μm. The grinding sand is filtered out, and the remaining defoamer and mixed solvent B are added. The mixture is stirred evenly, filtered, packaged, and ready for use.

6. The application of a radiation-resistant topcoat for nuclear power plants as described in any one of claims 1-4 in the nuclear island containment, nuclear auxiliary concrete building, and steel structure facilities and equipment.

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