Method for detecting chlorine salt erosion of concrete in nuclear power plant site

Abstract

The invention belongs to the technical field of nuclear power, and particularly relates to a method for detecting chlorine salt erosion of concrete in a nuclear power plant site. According to the method, information of multiple aspects such as environment investigation, intuitive representation and harmful ion detection results is comprehensively considered, and multiple factors are comprehensively considered to comprehensively and accurately evaluate the chlorine salt erosion condition of the concrete; and formulating targeted protection measures according to the evaluation result so as to ensure the long-term safety and durability of the concrete structure in the nuclear power plant site. The method is easy and convenient to operate and high in accuracy, the concrete eroded by chlorine salt in the nuclear power plant site is accurately judged through a more scientific and comprehensive method, powerful support is provided for formulating targeted protection measures, and the method has great significance in guaranteeing safe operation of a nuclear power plant and prolonging the service life of a maritime work structure.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of nuclear power, and particularly relates to a method for detecting concrete erosion by chloride salt in a nuclear power plant site. BACKGROUND

[0002] During the construction and operation of a nuclear power plant, it is crucial to ensure the long-term safety and durability of marine structures. These structures are often exposed to high salinity and high humidity marine environments, and are at risk of long-term exposure to chloride salt erosion. Chloride salt erosion not only causes carbonation of concrete and corrosion of steel bars, but also causes cracking, delamination and spalling of concrete, posing a serious threat to the overall safety of the nuclear power plant.

[0003] In related technologies, the determination of concrete erosion by chloride salt in a nuclear power plant site only relies on the chloride ion content of the concrete. Although this can provide some information, it is often difficult to comprehensively and accurately assess the chloride salt erosion condition of the concrete. Therefore, it is necessary to improve the accuracy of the determination of concrete erosion by chloride salt in a nuclear power plant site. SUMMARY

[0004] To overcome the problems in the related art, a method for detecting concrete erosion by chloride salt in a nuclear power plant site is provided, and the method comprises:

[0005] The method for detecting concrete erosion by chloride salt in a nuclear power plant site comprises:

[0006] Step 1: Obtain environmental data of the area where the nuclear power plant site is located, and determine whether the environmental data contains a chlorine source. If the environmental data does not contain a chlorine source, the subsequent steps of the detection method do not need to be performed. If the environmental data contains a chlorine source, the subsequent steps of the detection method are continued. The environmental data is used to represent the meteorological and seawater conditions of the area where the nuclear power plant site is located.

[0007] Step 2: Check the steel bar corrosion and carbonation of the concrete in the area where the nuclear power plant site is located. If the concrete in the area where the nuclear power plant site is located does not have steel bar corrosion and carbonation, the subsequent steps of the detection method do not need to be performed. If the concrete in the area where the nuclear power plant site is located has steel bar corrosion or carbonation, the subsequent steps of the detection method are continued.

[0008] Step 3: Perform atmospheric chloride ion deposition rate detection on the area where the nuclear power plant site is located to obtain the annual average atmospheric chloride ion deposition rate of the area where the nuclear power plant site is located.

[0009] Step 4: Perform chloride ion content detection on the corroded concrete in the nuclear power plant site.

[0010] Step 5, according to the monitored annual average deposition rate of atmospheric chloride ions in the region where the nuclear power plant site is located and the chloride ion content of the concrete, the corrosion reason of the corroded concrete in the nuclear power plant site is determined and the corrosion prevention treatment is carried out.

[0011] In a possible implementation, the environmental data includes meteorological data of the region, data of corrosive ions harmful to concrete, and seawater basic data including salinity, silt content, ion species and ion content of seawater.

[0012] In a possible implementation, in step 2, the steel bar corrosion caused by chloride salt erosion includes: along the crack, the steel bar is exposed, the concrete protective layer is cracked and peeled off; the carbonation includes: the surface color of the concrete becomes lighter, or white or light gray spots or stripes appear.

[0013] In a possible implementation, in step 2, if the surface color of the concrete becomes lighter, or white or light gray spots or stripes appear, a detection hole is further drilled on the surface of the concrete, and phenolphthalein alcohol solution is dropped into the detection hole. If the surrounding of the detection hole becomes red, it indicates that the concrete does not exist carbonation. If the surrounding of the detection hole does not change color, it indicates that the concrete exists carbonation.

[0014] In a possible implementation, in step 3, the atmospheric chloride ion deposition rate is detected by using the coupon method or the wet candle method, and the atmospheric chloride ion deposition rate in the region where the nuclear power plant site is located is classified according to the detection result of the atmospheric chloride ion deposition rate.

[0015] In a possible implementation, in step 4, the corroded concrete in the nuclear power plant site is obtained by core drilling sampling, and then the corroded concrete is ground layer by layer to obtain powder by using a concrete grinder or a drilling machine. The grinding direction is perpendicular to the chloride ion penetration surface; sampling is carried out within a preset depth range, and the obtained samples are filtered through a screen and then the chloride ion content is determined by chemical titration method, ion chromatography method or electrochemical method.

[0016] In a possible implementation, step 5 includes:

[0017] In the case that the detection result meets the first judgment condition and the second judgment condition, the corrosion prevention measures of removing chloride in the concrete and removing rust on the surface of the concrete are taken for the corroded concrete;

[0018] In the case that the detection result meets the first judgment condition but does not meet the second judgment condition, the protection measures are taken for the corroded concrete to prevent the invasion of chloride ions;

[0019] In the case that the detection result does not satisfy the first judgment condition but satisfies the second judgment condition, internal chloride removal measures are taken for the eroded concrete, and the source of chloride ions is investigated;

[0020] In the case that the detection result does not satisfy the first judgment condition and the second judgment condition, the concrete does not need to be protected from chloride ions;

[0021] The first judgment condition is that the annual average deposition rate of atmospheric chloride ions is greater than 3 mg / (m 2 ·d);

[0022] The second judgment condition is that the free chloride ion content of the concrete at a penetration depth of 10 mm is greater than 0.1%.

[0023] The disclosure has the beneficial effects that the disclosure comprehensively considers environmental investigation, intuitive performance, harmful ion detection results and other information, comprehensively considers various factors to accurately evaluate the chloride salt erosion condition of the concrete, and formulates targeted protection measures according to the evaluation results to ensure the long-term safety and durability of the concrete structure in the nuclear power plant site. The method of the disclosure is simple to operate and high in accuracy, aims to accurately determine the chloride salt eroded concrete in the nuclear power plant site by a more scientific and comprehensive method, and provides strong support for formulating targeted protection measures, can avoid unnecessary repair and replacement costs, improves economic benefits, and has important significance for ensuring the safe operation of the nuclear power plant and prolonging the service life of the marine structure. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a flowchart of a determination method of a chloride salt eroded concrete in a nuclear power plant site according to an embodiment of the disclosure.

[0025] Figures 2a to 2c is a schematic diagram of the corrosion condition of the steel bars on the surface of the concrete according to an embodiment of the disclosure.

[0026] Figure 3 is a diagram of the annual atmospheric chloride ion deposition rate of a certain sampling point in a certain nuclear power plant site;

[0027] Figure 4 is a diagram of the free chloride ion content of the eroded concrete in a certain nuclear power plant site DETAILED DESCRIPTION

[0028] The disclosure will be further described in detail below with reference to the drawings and specific embodiments.

[0029] Unless otherwise defined, technical and scientific terms used in the present disclosure have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs; the terminology used in the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure; the use of the terms "including," "comprising," or "having" in the present disclosure are meant to encompass the items listed thereafter, as well as their equivalents. It is expressly intended that all embodiments described in the present disclosure are merely embodiments among others, and are not the only embodiments which would be encompassed by the present disclosure. Numerous modifications and adaptations thereof will be apparent to those skilled in the art without departing from the spirit and scope of the present disclosure.

[0030] Reference herein to an "embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the disclosure. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive or alternative embodiments. It is expressly understood that the embodiments described herein are merely examples from among other embodiments that can be combined with each other.

[0031] Figure 1 is a flow chart of a method for determining whether concrete at a nuclear power plant site is eroded by chloride salt according to an embodiment of the present disclosure, as shown in Figure 1 , the detection method comprises:

[0032] Step 1, obtaining environmental data of the area where the nuclear power plant site is located. The environmental data includes meteorological data of the area, data of corrosive ions harmful to concrete, and seawater basic data including salinity, silt content, ion species and ion content of seawater. If the environmental data does not contain chlorine source, the subsequent steps of the method do not need to be executed; if the environmental data contains chlorine source, the subsequent steps of the method continue to be executed.

[0033] Step 2, checking the steel bar corrosion and carbonation of the concrete in the area where the nuclear power plant site is located. If the concrete in the area where the nuclear power plant site is located does not have steel bar corrosion and carbonation, the subsequent steps of the method do not need to be executed; if the concrete in the area where the nuclear power plant site is located has steel bar corrosion or carbonation, the concrete has been eroded, and the subsequent steps of the method continue to be executed. As shown in Figures 2a to 2c , the steel bar corrosion caused by chloride salt erosion includes: along the crack, the steel bar is exposed, the concrete protective layer is cracked and peeled off; the carbonation includes: the surface color of the concrete becomes lighter, or white or light gray spots or stripes appear; further, a detection hole can be drilled on the surface of the concrete where the above-mentioned situation occurs, and phenolphthalein alcohol solution is dropped into the detection hole. If the surrounding of the detection hole becomes red, it indicates that the concrete does not have carbonation; if the surrounding of the detection hole does not change color, it indicates that the concrete has carbonation.

[0034] Step 3: Detect the atmospheric chloride ion deposition rate of the region where the nuclear power plant site is located to obtain the annual average deposition rate of the atmospheric chloride ion of the region where the nuclear power plant site is located.

[0035] In step 3, the coupon method or wet candle method can be used to detect the atmospheric chloride ion deposition rate, and the atmospheric chloride ion deposition rate in the region where the nuclear power plant site is located is classified according to the detection results of the atmospheric chloride ion deposition rate. For example, according to the standards such as GB / T 19292.1-2018 Corrosion of Metals and Alloys - Part 1: Classification, Determination and Evaluation of Atmospheric Corrosivity, GB / T 19292.3-2018 Corrosion of Metals and Alloys - Part 3: Collection of Parameters Influencing Atmospheric Corrosivity Environment, etc., the atmospheric chloride ion deposition rate in the region where the nuclear power plant site is located is classified according to the detection results of the atmospheric chloride ion deposition rate by using a preset conversion model.

[0036] Step 4: Detect the chloride ion content of the corroded concrete in the nuclear power plant site.

[0037] The corroded concrete in the nuclear power plant site is obtained by core sampling, etc., and then the corroded concrete is ground layer by layer by using a concrete grinder or a drill, etc., and the grinding direction is perpendicular to the chloride ion penetration surface; sampling is performed within a preset depth range, and the obtained samples are filtered by a screen (for example, screened by a 0.63mm square hole screen), and then the chloride ion content is determined by chemical titration, ion chromatography or electrochemistry, etc.

[0038] Step 5: According to the monitored annual average deposition rate of the atmospheric chloride ion of the region where the nuclear power plant site is located and the chloride ion content of the concrete, the corrosion reason of the corroded concrete in the nuclear power plant site is determined and the corrosion prevention treatment is performed, including:

[0039] In the case where the detection results meet the first judgment condition and the second judgment condition, the corrosion prevention measures of removing chloride from the interior of the concrete combined with removing rust from the surface of the concrete are taken for the corroded concrete;

[0040] In the case where the detection results meet the first judgment condition but do not meet the second judgment condition, protective measures are taken for the corroded concrete to prevent the invasion of chloride ions;

[0041] In the case where the detection results do not meet the first judgment condition but meet the second judgment condition, internal chloride removal measures are taken for the corroded concrete, and the source of chloride ions is investigated;

[0042] In the case where the detection results do not meet the first judgment condition and the second judgment condition, no chloride protection treatment is needed for the concrete;

[0043] The first judgment condition is that the annual average deposition rate of atmospheric chloride ions is greater than 3 mg / (m 2 ·d.

[0044] The second judgment condition is that the free chloride ion content of the concrete at a penetration depth of 10 mm is greater than 0.1%.

[0045] In an application example, environmental investigation is carried out on the area where the nuclear power plant site is located, and environmental investigation is carried out on the area where the concrete is located, mainly including meteorological data and basic data related to seawater.

[0046] The steel chloride salt corrosion investigation is carried out on the area where the nuclear power plant site is located, and the steel corrosion condition within a range of 50 m near the area where the corroded concrete is located is observed. At the same time, there is no carbonization phenomenon in the concrete in this area.

[0047] The atmospheric chloride ion deposition rate detection is carried out on the area where the nuclear power plant site is located, the hanging piece method is used for the atmospheric chloride ion deposition rate detection, and the ion chromatography is used for the determination of the atmospheric chloride ion content.

[0048] The chloride ion content detection is carried out on the corroded concrete in the nuclear power plant site, the corroded concrete in the nuclear power plant site is obtained by core drilling sampling, and then the corroded concrete is ground layer by layer by using a concrete grinder to obtain powder, and the chloride ion content is determined by chemical titration method.

[0049] Test results: there are steel exposure and concrete protective layer peeling in the area within a range of 50 m near the area where the corroded concrete is located. At the same time, the atmospheric chloride ion deposition rate (see Figure 3 and Figure 4 ) in this area is detected, and the annual average deposition rate is 9.51 mg / (m 2 ·d). The chloride ion penetration depth of the corroded concrete is greater than 10 mm, and the chloride ion content at a depth of 10 mm is 0.117%.

[0050] The test results simultaneously satisfy the first judgment condition and the second judgment condition, and the measures of concrete internal chloride removal + concrete surface rust removal should be taken for the concrete in the area.

[0051] The above has described various embodiments of the present disclosure, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments. The selection of the terms used herein is intended to best explain the principles, practical applications, or improvements to the technology in the market of the embodiments, or to enable other ordinary skilled persons in the art to understand the embodiments disclosed herein.

Claims

1. A method for detecting chloride salt attack of concrete in a nuclear power plant site, characterized by, The detection method comprises: Step 1, obtaining environmental data of a region where the nuclear power plant site is located, and judging whether the environmental data has a chlorine source; if the environmental data does not have a chlorine source, subsequent steps of the detection method do not need to be performed; if the environmental data has a chlorine source, subsequent steps of the detection method continue to be performed, and the environmental data is used to represent meteorological and seawater conditions of the region where the nuclear power plant site is located; Step 2, checking a steel bar corrosion condition and a carbonation condition of concrete in the region where the nuclear power plant site is located, if the concrete in the region where the nuclear power plant site is located does not have the steel bar corrosion condition and the carbonation condition, subsequent steps of the detection method do not need to be performed; if the concrete in the region where the nuclear power plant site is located has the steel bar corrosion condition or the carbonation condition, subsequent steps of the detection method continue to be performed; Step 3, detecting an atmospheric chloride ion deposition rate of the region where the nuclear power plant site is located, to obtain an annual average atmospheric chloride ion deposition rate of the region where the nuclear power plant site is located; Step 4, detecting a chloride ion content of the corroded concrete in the nuclear power plant site; Step 5, judging a corrosion reason of the corroded concrete in the nuclear power plant site and performing a corrosion prevention treatment according to the annual average atmospheric chloride ion deposition rate of the region where the nuclear power plant site is located and the chloride ion content of the concrete.

2. The method of claim 1, wherein, The environmental data comprises meteorological data of the region, data of corrosive ions harmful to the concrete, and seawater basic data, the seawater basic data comprising salinity, silt content, ion types and ion contents of seawater.

3. The method of claim 1, wherein, In step 2, the steel bar corrosion condition caused by chloride salt erosion comprises: following a steel bar crack, a steel bar exposure, a concrete protective layer cracking and falling off; the carbonation condition comprises: a surface color of the concrete becoming lighter, or white or light gray spots or stripes appearing.

4. The method of claim 3, wherein, In step 2, if the surface color of the concrete becomes lighter, or white or light gray spots or stripes appear, a detection hole is further drilled on the surface of the concrete, and a phenolphthalein alcohol solution is dripped into the detection hole, if the surrounding of the detection hole becomes red, it indicates that the concrete does not have the carbonation condition, if the surrounding of the detection hole does not change color, it indicates that the concrete has the carbonation condition.

5. The method of claim 1, wherein, In step 3, the atmospheric chloride ion deposition rate detection is performed by using a coupon method or a wet candle method, and the atmospheric chloride ion deposition rate in the region where the nuclear power plant site is located is classified according to the atmospheric chloride ion deposition rate detection result.

6. The method of claim 1, wherein, In step 4, the corroded concrete in the nuclear power plant site is obtained by core drilling sampling, and then the corroded concrete is ground layer by layer by using a concrete grinder or a drilling machine to obtain powder, a grinding direction being perpendicular to a chloride ion penetration surface; sampling is performed within a preset depth range, and the obtained samples are filtered through a screen and then the chloride ion content is determined by using a chemical titration method, an ion chromatography method or an electrochemical method.

7. The method of claim 1, wherein, Step 5 comprises: In a case where the detection result satisfies the first judgment condition and the second judgment condition, corrosion prevention measures of removing chloride in the concrete and removing rust on the surface of the concrete are taken for the corroded concrete; In a case where the detection result satisfies the first judgment condition but does not satisfy the second judgment condition, a protection measure is taken for the corroded concrete to prevent the chloride from invading; In the case that the detection result does not satisfy the first judgment condition but satisfies the second judgment condition, internal chloride removal measures are taken for the eroded concrete, and the source of chloride ions is investigated; In the case that the detection result does not satisfy the first judgment condition and the second judgment condition, the concrete does not need to be protected from chloride ions; The first judgment condition is that the annual average deposition rate of atmospheric chloride ions is greater than 3 mg / (m 2 d); The second judgment condition is that the free chloride ion content of the concrete at a penetration depth of 10 mm is greater than 0.1%.

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