Method for predicting service life of boric acid solution corroded concrete member of nuclear power plant

Abstract

The invention particularly relates to a method for predicting the service life of a boric acid solution corrosion concrete member in a nuclear power plant. The method comprises the following steps: determining boric acid solution accelerated corrosion concrete member test control parameters; based on the boric acid solution accelerated corrosion concrete member test control parameters, boric acid solution accelerated corrosion concrete member tests are carried out in groups; constructing a boric acid solution corrosion concrete member life prediction model based on boric acid solution accelerated corrosion concrete member test data; and predicting the boric acid solution corrosion concrete member service life based on the boric acid solution corrosion concrete member service life prediction model. According to the method, a model for predicting the service life of the concrete member corroded by the boric acid solution is established by considering the water-binder ratio of the concrete, the temperature, the concentration of the boric acid solution and the corrosion time on the basis of research test results of physical properties and macroscopic mechanical properties of the concrete member corroded by the boric acid solution or field actual measurement data; and the service life of the boric acid solution corroded concrete member is predicted.

Description

Technical Field

[0001] The invention relates to the technical field of durability prediction of concrete components of nuclear power plants, and in particular to a method for predicting the service life of concrete components corroded by boric acid solution in nuclear power plants. Background Art

[0002] Boric acid solution exists in the cooling water system and its auxiliary systems of nuclear power plants, such as JNK water tanks. With the increase of service life, JNK water tanks may leak, and the leaked boric acid solution will enter the interior of concrete components and react with alkaline substances in the concrete components, causing decalcification and dissolution of cement paste hydration products in the concrete components, and reducing the pH value inside the concrete components and increasing the porosity. As the porosity of concrete components increases, internal pores and cracks expand and penetrate each other until macro cracks are formed, resulting in durability failure of concrete components and endangering the safe and stable operation of nuclear power plants.

[0003] There are very few existing related studies, and they are mainly based on indoor rapid tests for several concrete component performance indicators. Since the test environment of indoor rapid tests is not completely consistent with the actual engineering environment, it is still impossible to consider the influence of variables such as concrete water-cement ratio, temperature, boric acid solution concentration, and corrosion time. The degradation law of various physical and mechanical properties of concrete components under the action of boric acid solution is still unclear, and it is impossible to quantitatively judge the degree of aging of concrete components corroded by boric acid solution and whether it will affect the normal operation of the power station. It is urgent to establish a life prediction model for concrete components corroded by boric acid solution to provide a scientific basis for the durability evaluation of concrete components corroded by boric acid solution. Summary of the invention

[0004] The purpose of the present invention is to provide a method for predicting the service life of concrete components corroded by boric acid solution in nuclear power plants, so as to solve the problem that the service life of concrete components corroded by boric acid solution cannot be quantitatively determined. Based on the test results of physical properties and macroscopic mechanical properties of concrete components corroded by boric acid solution or field measured data, the service life prediction model of concrete components corroded by boric acid solution is established by considering the concrete water-binder ratio, temperature, boric acid solution concentration and corrosion time, so as to realize the prediction of the service life of concrete components corroded by boric acid solution.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A method for predicting the service life of concrete components corroded by boric acid solution in a nuclear power plant comprises the following steps:

[0007] Step 1, determining the control parameters of the test on accelerated corrosion of concrete components by boric acid solution;

[0008] Step 2, based on the control parameters of the boric acid solution accelerated corrosion concrete component test, the boric acid solution accelerated corrosion concrete component test was performed in groups;

[0009] Step 3: Based on the test data of accelerated corrosion of concrete components by boric acid solution, a life prediction model of concrete components corroded by boric acid solution is constructed;

[0010] Step 4: Predict the life of concrete components corroded by boric acid solution based on the life prediction model of concrete components corroded by boric acid solution.

[0011] In the present invention, in step 1, the test control parameters of the accelerated corrosion of concrete components by the boric acid solution are determined by investigating the service environment of the concrete components corroded by the boric acid solution and investigating the concrete design parameters;

[0012] The service environment investigation of boric acid solution corrosion of concrete components includes investigating the environmental temperature, boric acid solution concentration and boric acid solution temperature of boric acid solution corrosion of concrete components;

[0013] The investigation of concrete design parameters for concrete components corroded by boric acid solution includes investigating the concrete water-cement ratio and steel bar protective layer thickness of concrete components corroded by boric acid solution;

[0014] The experimental control parameters of accelerated corrosion of concrete components by boric acid solution include concrete water-cement ratio, boric acid solution concentration, corrosion time, ambient temperature and boric acid solution temperature.

[0015] In the present invention, in step 2, based on the control parameters of the boric acid solution accelerated corrosion of concrete components test, the boric acid solution accelerated corrosion of concrete components test is carried out in groups, comprising the following steps:

[0016] (1) Three concentrations of boric acid solution were set: a blank control group, a boric acid solution concentration simulating a nuclear power plant refueling pool, and an accelerated corrosion test concentration; during the test, the concrete components were completely immersed in the boric acid solution, and the boric acid solution was replaced regularly according to the pH value of the boric acid solution;

[0017] (2) Set two temperatures: ambient temperature and boric acid solution temperature;

[0018] (3) Measure the mass loss, corrosion depth, cube compressive strength, axial compressive strength, splitting tensile strength and elastic modulus of concrete components every 30 days until 360 days.

[0019] In the present invention, the life prediction model of concrete components corroded by boric acid solution includes a prediction model based on mass loss rate, a prediction model based on corrosion depth, a prediction model based on cube compressive strength loss rate, a prediction model based on axial compressive strength loss rate, a prediction model based on splitting tensile strength loss rate and a prediction model based on elastic modulus loss rate.

[0020] In the present invention, the prediction model based on the mass loss rate is calculated as follows:

[0021]

[0022]

[0023] Where, ΔW is the predicted value of mass loss rate of concrete components, in %; (ΔW) i t i The mass loss rate of the concrete component at 28 days of curing, in %, G0 is the dry weight of the concrete component after 28 days of curing, in g; G ti t i is the dry weight of the concrete component at t, in g; t is the time for the boric acid solution to corrode the concrete component, in d; t i is the starting time of corroding concrete components by boric acid solution, in d; a1 and b1 are both fitting parameters;

[0024] When ΔW exceeds 5%, it is determined that the concrete component has reached its service limit state, and the service life prediction of the concrete structure corroded by boric acid solution based on the mass loss rate is realized.

[0025] In the present invention, the prediction model based on the corrosion depth is calculated as follows:

[0026]

[0027] Where h is the predicted corrosion depth of the concrete component, in mm; t is the time for the boric acid solution to corrode the concrete component, in d; t i is the starting time of corroding concrete components by boric acid solution, in d; k is the corrosion rate, in mm·d 0.5 .

[0028] In the present invention, the prediction model based on the cube compressive strength loss rate is calculated as follows:

[0029]

[0030]

[0031] Where, d c is the predicted value of the cubic compressive strength loss rate of the concrete component, in %; (d c ) i is the cubic compressive strength loss rate of the concrete component, in %; f cb The cubic compressive strength of a concrete component measured for inspection or testing; f cn is the cubic compressive strength of concrete components in natural curing water; t is the time for boric acid solution to corrode concrete components, in d; t iis the starting time of corroding concrete components by boric acid solution, in d; a2 and b2 are both fitting parameters;

[0032] When c If it exceeds 25%, the concrete component is judged to have reached the service limit state, and the service life prediction of the concrete structure corroded by boric acid solution based on the cube compressive strength loss rate is realized.

[0033] In the present invention, based on the prediction model of axial compressive strength loss rate, the calculation formula is:

[0034]

[0035]

[0036] Where, d a is the predicted value of the axial compressive strength loss rate of the concrete component, in %; (d a ) i is the axial compressive strength loss rate of the concrete component, in %; f ab The axial compressive strength of the concrete component measured by inspection or test; an is the axial compressive strength of concrete components in natural curing water; t is the time for boric acid solution to corrode concrete components, in d; t i is the starting time of corroding concrete components by boric acid solution, in d; a3 and b3 are both fitting parameters;

[0037] When a If it exceeds 25%, the concrete component is judged to have reached the service limit state, and the service life prediction of the concrete component corroded by boric acid solution based on the axial compressive strength loss rate is realized.

[0038] In the present invention, based on the prediction model of splitting tensile strength loss rate, the calculation formula is:

[0039]

[0040]

[0041] Where, d t is the predicted value of the splitting tensile strength loss rate of the concrete component, in %; (d t ) i is the splitting tensile strength loss rate of the concrete component, in %; f tb The splitting tensile strength of a concrete component measured for inspection or testing; tn is the splitting tensile strength of concrete components in natural curing water; t is the time for boric acid solution to corrode concrete components, in d; t iis the starting time of corroding concrete components by boric acid solution, in d; a4 and b4 are both fitting parameters;

[0042] When t If it exceeds 25%, the concrete component is judged to have reached the service limit state, and the service life prediction of the concrete component corroded by boric acid solution based on the splitting tensile strength loss rate is realized.

[0043] In the present invention, the prediction model based on the elastic modulus loss rate is calculated as follows:

[0044]

[0045]

[0046] Where, d e is the predicted value of elastic modulus loss rate of concrete components, in %; (d e ) i is the loss rate of elastic modulus of concrete, in %; E b The elastic modulus of the concrete component measured for inspection or testing; E n is the elastic modulus of the concrete component in natural curing water; t is the time for the boric acid solution to corrode the concrete component, in d; t i is the starting time of corroding concrete components by boric acid solution, in d; a5 and b5 are fitting parameters;

[0047] When e If it exceeds 25%, the concrete component is judged to have reached the service limit state, and the service life prediction of concrete components corroded by boric acid solution based on the elastic modulus loss rate is realized.

[0048] Beneficial technical effects of the present invention:

[0049] The method for predicting the service life of concrete components corroded by boric acid solutions in nuclear power plants of the present invention is based on the test results of physical properties and macroscopic mechanical properties of concrete components corroded by boric acid solutions or field measured data, and takes into account the water-cement ratio of concrete, temperature, boric acid solution concentration and corrosion time, so as to construct a performance evaluation and analysis model of concrete components under different boric acid solution corrosion environments, and then establish a service life prediction model of concrete components corroded by boric acid solutions under multi-factor coupling conditions, thereby realizing the prediction of the service life of concrete components corroded by boric acid solutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 A flowchart of an embodiment of a method for predicting the service life of a concrete component corroded by a boric acid solution in a nuclear power plant according to the present invention;

[0051] Figure 2The figure is a relationship between the service life of a concrete component corroded by a boric acid solution and the loss rate of cube compressive strength according to an embodiment. DETAILED DESCRIPTION

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used in the specification of the application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0053] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0054] The technical solution of the present invention is clearly and completely described below in conjunction with the accompanying drawings and specific embodiments.

[0055] See also Figure 1 This embodiment provides a method for predicting the service life of concrete components corroded by boric acid solution in a nuclear power plant, comprising the following steps:

[0056] Step 1, determining the control parameters of the test on accelerated corrosion of concrete components by boric acid solution;

[0057] Step 2, based on the control parameters of the boric acid solution accelerated corrosion concrete component test, the boric acid solution accelerated corrosion concrete component test was performed in groups;

[0058] Step 3: Based on the test data of accelerated corrosion of concrete components by boric acid solution, a life prediction model of concrete components corroded by boric acid solution is constructed;

[0059] Step 4: Predict the life of concrete components corroded by boric acid solution based on the life prediction model of concrete components corroded by boric acid solution.

[0060] In this embodiment, in step 1, the control parameters of the test on accelerated corrosion of concrete components by boric acid solution are determined through investigation of the service environment of concrete components corroded by boric acid solution and investigation of concrete design parameters;

[0061] The service environment investigation of boric acid solution corrosion of concrete components includes investigating the environmental temperature, boric acid solution concentration and boric acid solution temperature of boric acid solution corrosion of concrete components;

[0062] The investigation of concrete design parameters for concrete components corroded by boric acid solution includes investigating the concrete water-cement ratio and steel bar protective layer thickness of concrete components corroded by boric acid solution;

[0063] The experimental control parameters of accelerated corrosion of concrete components by boric acid solution include concrete water-cement ratio, boric acid solution concentration, corrosion time, ambient temperature and boric acid solution temperature.

[0064] In this embodiment, in step 2, based on the control parameters of the boric acid solution accelerated corrosion concrete component test, the boric acid solution accelerated corrosion concrete component test is performed in groups, including the following steps:

[0065] (1) Three concentrations of boric acid solution were set: a blank control group, a boric acid solution concentration simulating a nuclear power plant refueling pool, and an accelerated corrosion test concentration; during the test, the concrete components were completely immersed in the boric acid solution, and the boric acid solution was replaced regularly according to the pH value of the boric acid solution;

[0066] (2) Set two temperatures: ambient temperature and boric acid solution temperature;

[0067] (3) Measure the mass loss, corrosion depth, cube compressive strength, axial compressive strength, splitting tensile strength and elastic modulus of concrete components every 30 days until 360 days.

[0068] In this embodiment, the life prediction model of concrete components corroded by boric acid solution includes a prediction model based on mass loss rate, a prediction model based on corrosion depth, a prediction model based on cube compressive strength loss rate, a prediction model based on axial compressive strength loss rate, a prediction model based on splitting tensile strength loss rate and a prediction model based on elastic modulus loss rate.

[0069] In this embodiment, the prediction model based on the mass loss rate is calculated as follows:

[0070]

[0071]

[0072] Where, ΔW is the predicted value of mass loss rate of concrete components, in %; (ΔW) i t i The mass loss rate of the concrete component at 28 days of curing, in %; G0 is the dry weight of the concrete component after 28 days of curing, in g; t i is the dry weight of the concrete component at t, in g; t is the time for the boric acid solution to corrode the concrete component, in d; t i is the starting time of corroding concrete components by boric acid solution, in d; a1 and b1 are both fitting parameters;

[0073] When ΔW exceeds 5%, it is determined that the concrete component has reached its service limit state, and the service life prediction of the concrete structure corroded by boric acid solution based on the mass loss rate is realized.

[0074] In this embodiment, a1 and b1 are determined based on the actual environmental conditions of the concrete component, existing engineering surveys and laboratory data. When reliable data is lacking, the following table is used:

[0075]

[0076]

[0077] In this embodiment, the calculation formula based on the prediction model of corrosion depth is:

[0078]

[0079] Where h is the predicted corrosion depth of the concrete component, in mm; t is the time for the boric acid solution to corrode the concrete component, in d; t i is the starting time of corroding concrete components by boric acid solution, in d; k is the corrosion rate, in mm·d 0.5 .

[0080] In this embodiment, k is determined based on the actual environmental conditions of the concrete component, existing engineering surveys and laboratory data. When reliable data is lacking, it can be taken from the following table:

[0081]

[0082] The prediction model based on corrosion depth can predict the corrosion depth of concrete components corroded by boric acid solution at any corrosion time.

[0083] In this embodiment, based on the prediction model of cube compressive strength loss rate, the calculation formula is:

[0084]

[0085]

[0086] Where, d c is the predicted value of the cubic compressive strength loss rate of the concrete component, in %; (d c ) i is the cubic compressive strength loss rate of the concrete component, in %; f cb The cubic compressive strength of a concrete component measured for inspection or testing; f cn is the cubic compressive strength of concrete components in natural curing water; t is the time for boric acid solution to corrode concrete components, in d; t iis the starting time of corroding concrete components by boric acid solution, in d; a2 and b2 are both fitting parameters;

[0087] When c If it exceeds 25%, the concrete component is judged to have reached the service limit state, and the service life prediction of the concrete structure corroded by boric acid solution based on the cube compressive strength loss rate is realized.

[0088] In this embodiment, a2 and b2 are determined based on the actual environmental conditions of the concrete component building, existing engineering surveys and laboratory data; when reliable data is lacking, the following table can be used:

[0089]

[0090] In this embodiment, based on the prediction model of axial compressive strength loss rate, the calculation formula is:

[0091]

[0092]

[0093] Where, d a is the predicted value of the axial compressive strength loss rate of the concrete component, in %; (d a ) i is the axial compressive strength loss rate of the concrete component, in %; f ab The axial compressive strength of the concrete component measured by inspection or test; an is the axial compressive strength of concrete components in natural curing water; t is the time for boric acid solution to corrode concrete components, in d; t i is the starting time of corroding concrete components by boric acid solution, in d; a3 and b3 are both fitting parameters;

[0094] When a If it exceeds 25%, the concrete component is judged to have reached the service limit state, and the service life prediction of the concrete component corroded by boric acid solution based on the axial compressive strength loss rate is realized.

[0095] In this embodiment, a3 and b3 are determined based on the actual environmental conditions of the concrete component, existing engineering surveys and laboratory data; when reliable data is lacking, the following table can be used:

[0096]

[0097] In this embodiment, based on the prediction model of splitting tensile strength loss rate, the calculation formula is:

[0098]

[0099]

[0100] Where, d t is the predicted value of the splitting tensile strength loss rate of the concrete component, in %; (d t ) i is the splitting tensile strength loss rate of the concrete component, in %; f tb The splitting tensile strength of a concrete component measured for inspection or testing; tn is the splitting tensile strength of concrete components in natural curing water; t is the time for boric acid solution to corrode concrete components, in d; t i is the starting time of corroding concrete components by boric acid solution, in d; a4 and b4 are both fitting parameters;

[0101] When t If it exceeds 25%, the concrete component is judged to have reached the service limit state, and the service life prediction of the concrete component corroded by boric acid solution based on the splitting tensile strength loss rate is realized.

[0102] In this embodiment, a4 and b4 are determined based on the actual environmental conditions of the concrete member, existing engineering surveys and laboratory data. When reliable data is lacking, the following table can be used:

[0103]

[0104] In this embodiment, the prediction model based on the elastic modulus loss rate is calculated as follows:

[0105]

[0106]

[0107] Where, d e is the predicted value of elastic modulus loss rate of concrete components, in %; (d e ) i is the loss rate of elastic modulus of concrete, in %; E b The elastic modulus of the concrete component measured for inspection or testing; E n is the elastic modulus of the concrete component in natural curing water; t is the time for the boric acid solution to corrode the concrete component, in d; t i is the starting time of corroding concrete components by boric acid solution, in d; a5 and b5 are fitting parameters;

[0108] When e If it exceeds 25%, the concrete component is judged to have reached the service limit state, and the service life prediction of concrete components corroded by boric acid solution based on the elastic modulus loss rate is realized.

[0109] In this embodiment, a5 and b5 are determined based on the actual environmental conditions of the concrete member, existing engineering surveys and laboratory data. When reliable data is lacking, the following table can be used:

[0110]

[0111] The mass loss rate, corrosion depth, cube compressive strength loss rate, axial compressive strength loss rate, splitting tensile strength loss rate and elastic modulus loss rate of concrete components corroded by boric acid solution were measured through on-site detection methods under the same conditions, and the service life prediction analysis of concrete components corroded by boric acid solution was realized based on the measurement results.

[0112] Taking the concrete component with a water-binder ratio of 0.45 at a service environment temperature of 60°C as an example, when the concentration of the boric acid solution is 2500ppm, according to the ASTM standard, the 25% cubic compressive strength loss rate is used as the judgment condition for the service limit state of the corroded concrete component, and its service life is calculated to be 61.12 years. Figure 2 shown.

[0113] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for predicting the service life of concrete components corroded by boric acid solution in a nuclear power plant, characterized in that: The steps include: Step 1, determining the control parameters of the test on accelerated corrosion of concrete components by boric acid solution; Step 2, based on the control parameters of the boric acid solution accelerated corrosion concrete component test, the boric acid solution accelerated corrosion concrete component test was performed in groups; Step 3: Based on the test data of accelerated corrosion of concrete components by boric acid solution, a life prediction model of concrete components corroded by boric acid solution is constructed; Step 4: Predict the life of concrete components corroded by boric acid solution based on the life prediction model of concrete components corroded by boric acid solution.

2. The method for predicting the service life of concrete components corroded by boric acid solution in nuclear power plants according to claim 1, characterized in that: In step 1, the test control parameters of the accelerated corrosion of concrete components by boric acid solution are determined through investigation of the service environment of concrete components corroded by boric acid solution and investigation of concrete design parameters; The service environment investigation of boric acid solution corrosion of concrete components includes investigating the environmental temperature, boric acid solution concentration and boric acid solution temperature of boric acid solution corrosion of concrete components; The investigation of concrete design parameters for concrete components corroded by boric acid solution includes investigating the concrete water-cement ratio and steel bar protective layer thickness of concrete components corroded by boric acid solution; The experimental control parameters of accelerated corrosion of concrete components by boric acid solution include concrete water-cement ratio, boric acid solution concentration, corrosion time, ambient temperature and boric acid solution temperature.

3. The method for predicting the service life of concrete components corroded by boric acid solution in nuclear power plants according to claim 2, characterized in that: In step 2, based on the control parameters of the boric acid solution accelerated corrosion concrete component test, the boric acid solution accelerated corrosion concrete component test is performed in groups, including the following steps: (1) Three concentrations of boric acid solution were set: a blank control group, a boric acid solution concentration simulating a nuclear power plant refueling pool, and an accelerated corrosion test concentration; during the test, the concrete components were completely immersed in the boric acid solution, and the boric acid solution was replaced regularly according to the pH value of the boric acid solution; (2) Set two temperatures: ambient temperature and boric acid solution temperature; (3) Measure the mass loss, corrosion depth, cube compressive strength, axial compressive strength, splitting tensile strength and elastic modulus of concrete components every 30 days until 360 days.

4. The method for predicting the service life of concrete components corroded by boric acid solution in nuclear power plants according to claim 3, characterized in that: The life prediction models of concrete components corroded by boric acid solution include a prediction model based on mass loss rate, a prediction model based on corrosion depth, a prediction model based on cube compressive strength loss rate, a prediction model based on axial compressive strength loss rate, a prediction model based on splitting tensile strength loss rate and a prediction model based on elastic modulus loss rate.

5. The method for predicting the service life of concrete components corroded by boric acid solution in nuclear power plants according to claim 4, characterized in that: The prediction model based on mass loss rate is calculated as follows: Where, ΔW is the predicted value of mass loss rate of concrete components, in %; (ΔW) i t i The mass loss rate of the concrete component at 28 days of curing, in %; G0 is the dry weight of the concrete component after 28 days of curing, in g; t i The dry weight of the concrete component at the time, in g; t is the time for the boric acid solution to corrode the concrete component, in d; t i is the starting time of corroding concrete components by boric acid solution, in d; a1 and b1 are both fitting parameters; When ΔW exceeds 5%, it is judged that the concrete component has reached the service limit state.

6. The method for predicting the service life of concrete components corroded by boric acid solution in nuclear power plants according to claim 4, characterized in that: Based on the prediction model of corrosion depth, the calculation formula is: Where, h is the predicted value of the corrosion depth of the concrete component, in mm; t is the time for the boric acid solution to corrode the concrete component, in d; t i is the starting time of corroding concrete components by boric acid solution, in d; k is the corrosion rate, in mm·d 0.5 .

7. The method for predicting the service life of concrete components corroded by boric acid solution in nuclear power plants according to claim 4, characterized in that: The prediction model based on the cube compressive strength loss rate is calculated as follows: Where, d c is the predicted value of the cubic compressive strength loss rate of the concrete component, in %; (d c ) i is the cubic compressive strength loss rate of the concrete component, in %; f cb The cubic compressive strength of a concrete component measured for inspection or testing; f cn is the cubic compressive strength of concrete components in natural curing water; t is the time for the boric acid solution to corrode the concrete component, in d; t i is the starting time of corroding concrete components by boric acid solution, in d; a2 and b2 are both fitting parameters; When c If it exceeds 25%, the concrete component is judged to have reached the service limit state.

8. The method for predicting the service life of concrete components corroded by boric acid solution in nuclear power plants according to claim 4, characterized in that: Based on the prediction model of axial compressive strength loss rate, the calculation formula is: Where, d a is the predicted value of the axial compressive strength loss rate of the concrete component, in %; (d a ) i is the axial compressive strength loss rate of the concrete component, in %; f ab The axial compressive strength of the concrete component measured by inspection or test; an is the axial compressive strength of concrete components in natural curing water; t is the time for boric acid solution to corrode concrete components, in d; t i is the starting time of corroding concrete components by boric acid solution, in d; a3 and b3 are both fitting parameters; When a If it exceeds 25%, the concrete component is judged to have reached the service limit state.

9. The method for predicting the service life of concrete components corroded by boric acid solution in nuclear power plants according to claim 4, characterized in that: Based on the prediction model of splitting tensile strength loss rate, the calculation formula is: Where, d t is the predicted value of the splitting tensile strength loss rate of the concrete component, in %; (d t ) i is the splitting tensile strength loss rate of the concrete component, in %; f tb The splitting tensile strength of a concrete component measured for inspection or testing; tn The splitting tensile strength of concrete components in natural curing water; t is the time for the boric acid solution to corrode the concrete component, in d; t i is the starting time of corroding concrete components by boric acid solution, in d; a4 and b4 are both fitting parameters; When t If it exceeds 25%, the concrete component is judged to have reached the service limit state.

10. The method for predicting the service life of concrete components corroded by boric acid solution in nuclear power plants according to claim 4, characterized in that: The prediction model based on the elastic modulus loss rate is calculated as follows: Where, d e is the predicted value of elastic modulus loss rate of concrete components, in %; (d e ) i is the loss rate of elastic modulus of concrete, in %; E b The elastic modulus of the concrete component measured for inspection or testing; E n is the elastic modulus of the concrete component in natural curing water; t is the time for the boric acid solution to corrode the concrete component, in d; t i is the starting time of corroding concrete components by boric acid solution, in d; a5 and b5 are fitting parameters; When e If it exceeds 25%, the concrete component is judged to have reached the service limit state.

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