Technical specification for anticorrosion operation of seawater circulation system in nuclear power plant
Some standard content:
ICS 25.220.99
National Standard of the People's Republic of China
GB/T 31404—2015
Technical Specification for Anticorrosion Operation of Seawater Circulation System in Nuclear Power Plant
Technical Specification for Anticorrosion Operation of Seawater Circulation System in Nuclear Power Plant plant2015-05-15 Issued
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China Standardization Administration of China
2015-10-01 Implementation
GB/T31404—2015
Normative references
Terms and definitions
Coating corrosion protection
Surface treatment
Maintenance and repair of coatings
Cathodic protection
General provisions
Protection potential
Protection current density
Electrical continuity
Electrical insulation device
Sacrificial anode cathodic protection system||t t||Impressed current cathodic protection system
System records and documents
Operation and maintenance
Corrosion monitoring and detection system
Sensors
7.2 Measurement and acquisition equipment
7.3 Data management system
Appendix A (informative appendix)
Calculation of sacrificial anode
Appendix B (informative appendix) Determination of protective potential of steel in seawater with different reference electrodes and corresponding relationship diagram Appendix C (informative appendix)
Appendix D (informative appendix)
Design and calculation of impressed current cathodic protection
Design and calculation of DC power supply
This standard is based on the rules given in GB/T 1.1--2CC9. This standard is formulated by China National Chemical Industry Federation and National Anti-Corrosion Chemical Technical Committee (SAC/TC381) GB/T31404-2015. The responsible drafting units of this standard are Suzhou Thermal Engineering Research Institute Co., Ltd., Akzo Nobel Protective Materials (Suzhou) Co., Ltd., Beijing Bihaizhou Corrosion Protection Industry Co., Ltd., China Industrial Corrosion Protection Technical Committee. Zhejiang Yonggu Weihua Coatings Co., Ltd., Xinjiang Zhongwang Chemical Co., Ltd., Qingdao Dalun Pipeline Anticorrosion and Insulation Equipment Co., Ltd., Xi'an Taijin Industrial Chemical Technology Co., Ltd., Xiyang Aerospace Xinxing Machinery Co., Ltd., Dalian Institute of Technology. The main contributors to this standard are: Liu Shuang, Xian Bing, Lin Chengquan, Gao Yuzhu, Fei Kexie, De Chongwen, Hao Jun, Liu Jinban, Zhang Wenli, Wang Lei, Chu Yanzhuan, Han He, Huo Yuping, Zhang Youzhi, Ge Longchang, Zhang Jingyuan, Jin Hui, Xia Baodong, Dui San: 1 Scope
Technical specification for anti-corrosion operation of seawater circulation system in nuclear power plant
GB/T 31404—2015
This standard specifies the general principles for anti-corrosion operation of seawater circulation system in nuclear power plant, and the technical requirements for coating, cathodic protection and inspection system. This standard is applicable to the anti-corrosion of seawater circulation system in coastal nuclear power plants. 2 Normative references
The following documents are indispensable for the use of this document. The version with the date of use is selected after the date of use. For any document without the date of use, its latest version (including all modifications) shall apply to this document. ! "Industrial design hygiene standard
C3/T1725
GE/T 1728
GE/T 1731
CE7T 1722
GT 1733
CE,T 1740
G3/T 1793
CHT 1771
GB/T 4913
GE/T 495C
GB/T 521C
G3/T 6750
GB/T 7387
GB/T 7388
GB/T 7790
Determination of drying time of paint film by nitrogen touch
Determination of rubbing resistance
Determination of impact resistance of paint mold
Determination of water resistance
Determination of paint and varnish resistance
Determination of salt resistance
Color and clear
Aluminum-aluminum alloy anode
Color and clear varnish adhesion test by tensile method
Determination of color and clarity
Comparison||tt| |Technical conditions for marine reference electrodes
Technical conditions for auxiliary anodes for grease
Determination of cathodic disbonding resistance of paints and varnishes exposed to seawaterGB/T8923.1—2011: Visual assessment of surface cleanliness of steel surfaces before coating Part 1: Rust grade and treatment grade of uncoated steel surfaces and steel surfaces after complete removal of existing coatingsGB/T8923.2—2008Surface treatment of steel before coating Visual assessment of surface cleanliness Grade of treatment of steel surfaces after partial removal of existing coatingsGB/T13452.2Determination of film thickness of paints and varnishes GB/T16166 Sacrificial anode cathodic protection for seawater cooling water systems in coastal power plants GB/T17005 Impressed current cathodic protection systems for coastal facilities Part 2: Tests for evaluating the surface cleanliness of steel surfaces before coating GB/T18570.3 Paints - Surface preparation of steel before coating - Tests for evaluating the surface cleanliness Part 3: Evaluation of dust on steel surfaces before coating (pressure sensitive adhesive tape method) GB/T18581 Indoor decoration and furnishing materials - Limits of hazardous substances in solvent-based wood coatings GB24108 Limits of hazardous substances in exterior wall coatings for buildings GB/T50087 Design specifications for noise control in industrial enterprises GB50726 Industrial .Corrosion protection of industrial equipment and pipelines.T.Process implementation.TSpecification 1
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GB/T31404—2015
CB*3220Technical conditions for constant potentiostat for ships
JTJ275Technical specification for corrosion protection of concrete structures in port engineering (with clause explanation)SY/T0063Test method for leakage detection of pipeline anti-corrosion layerSY/T0516Technical specification for insulating joints and insulating flangesISO12944-5Paints and varnishesCorrosion protection of steel structures by protective paint systems Part 5: Protective paint systems
3Terms and definitions
The following terms and definitions apply to this document. 3.1
Sacrifice cathodic protectionAn electrochemical protection method that provides a cathodic current to the protected body by connecting to a sacrificial anode. 3.2
Impressed current cathodic protectionAn electrochemical protection method that provides a cathodic current to the protected body by an external power supply. 3.3
Polarization
The phenomenon of electrode potential shift due to the flow of net current between metal and electrolyte. 4 General
4.1 When seawater is used as the cooling water source, a survey of the coastal hydrogeology and marine biological resources of the site should be conducted, and corresponding anti-corrosion measures should be taken according to the hydrogeological conditions and marine biological resources and their distribution. 4.2 The seawater circulation system of a nuclear power plant should adopt a combined protection measure of anti-corrosion coating and cathodic protection to prevent corrosion. Its effectiveness should be consistent with the design life of the power plant.
4.3 If there is a heat exchanger equipment designed downstream of important plant water pipelines, rubber lining with the risk of falling off in pieces should not be used as an anti-corrosion measure. 4.4 The quality assurance level of the protected system should be considered when determining the quality assurance level of the protection system. 4.5 The seismic resistance level of the protected system should be considered when determining the seismic resistance level of the protection system. 5 Coating anti-corrosion
5.1 Design
The design of anti-corrosion coatings and anti-fouling coatings should take into account the seawater environment, structural characteristics, expected working life, construction environment and construction conditions (construction season, factory painting, on-site painting and maintenance, etc.), on-site repainting conditions, and the economic rationality of the anti-corrosion coating and its coordination with cathodic protection.
5.2 Surface treatment
5.2.1 Requirements
Before painting, the substrate surface should be treated to make it dry, clean and free of foreign matter. 5.2.2 Grade
5.2.2.1 The quality control of surface rust removal of steel structures shall comply with the provisions of GB/T8923.12011, and the surface rust removal grade of steel structures shall reach 2
Sa25 specified in GB/T 8923.1-2011.2.2.2 The surface roughness shall reach 40um~75m, GB/T 31404-2015
5.2.2.3 The surface cleanliness shall be evaluated in accordance with GB/T18570.3. The dust quantity and inch grade shall not be higher than grade 2. 5.2.3 Painting time
Painting shall be carried out within 4 hours after the surface treatment is completed. 5.3 Coating
5.3.1 Performance requirements
The selected coating should be a thick paste type modified epoxy resin coating. The total coating thickness of the pipe should not be less than 800um, and the total coating thickness of the base equipment should not be less than 350um. However, the thickness should not be more than twice the minimum thickness. The test results of the performance should comply with Table 1 and Table 2. The coating performance requirements
Ten years ago
Composite material/head
Density/(KL)
Compound material:) content/g
Drying time
: c)
Hexavalent iodine (C-\)
Mercury (Hg)
Hardness/h
Adhesion/MFa
Flexibility/mm
Impact resistance/cm
Abrasion resistance(1 000 g/1 000 1,CS10)/mg Cathodic stripping resistance (1.5V,30 d)/I
Heat resistance/a
Water immersion resistance/rising
Salt spray resistance/h
Oxygen ion penetration resistance/[mg/(cm,)]
Quality index
The hardness after mixing
2 Coating performance requirements
Quality index
5.12×10-6
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GET1728
G3/T 13:3:
G 2-012
GE24403
CE'T 1723
G3/T 1728
Battle test method
GB/ 5210
CB/T 1731
GB/T 1768
GB/T 7790
GB/T 1733
CB/T 17 71
JTJ 275
GB/T 31404—20t5
5.3.2 Grade
The grading rules for anti-corrosion coatings shall be in accordance with the provisions of ISO12944-5 and can be divided into three grades: low, medium and high. The durability range is shown in Table 3.
Table 3 Durability Grade
Coating Grade
5.3.3 Safety, Health and Environmental Protection Requirements The following safety, health and environmental protection requirements shall be met during the construction of anti-corrosion coatings: a) Safety standard control shall comply with the provisions of GB50726; b) The noise generated by various equipment shall comply with the provisions of GB/T50087; c) The dust content in the air shall comply with the provisions of GBZ1; and durability/a
d) Electrical equipment shall comply with the provisions of the Electrical Safety Regulations for Explosion Hazardous Locations of the People's Republic of China. Electrical facilities shall be explosion-proof as a whole, and the operating part shall be equipped with electric shock protectors; the rotating and moving parts of all mechanical facilities shall be equipped with protective covers and other protective facilities; construction personnel shall be equipped with appropriate safety protection equipment. 5.3.4 Painting
Factory painting shall meet the following requirements:
Construction shall be carried out in accordance with the coating construction process;
The exposed surface formed by the reserved part shall be painted with primer; b)
The integrity, continuity and adhesion of the coating to the substrate shall be ensured, and the performance shall meet the requirements of Table 2. c)
2 On-site painting shall meet the following requirements:
According to the coating curing requirements, determine the construction environment, the ambient temperature shall not be lower than 0℃, and the surface temperature of the tree shall be at least 3℃ higher than the dry dew point temperature;
According to the surface treatment requirements, determine the surface treatment process, b)
The completion shall meet the management and painting quality control requirements of on-site construction. c
Inspection, acceptance, storage, transportation and installation of equipment 5.3.5
Quality inspection of equipment after coating shall comply with the following provisions before acceptance: 5.3.5.1
Appearance: Visual inspection shall show no defects such as sagging, bubbles, damage, cracks, peeling, etc. a)
Thickness: Use a thickness gauge to measure the dry film thickness, which shall comply with GB/T13452.2; b)
Adhesion: Use the pull-off method to measure the adhesion Force, should comply with GB/T5210; e
Continuity: Use spark detector for leak detection, should comply with SY/T0063, and calculated according to formula (1) and formula (2): When the thickness of the anti-corrosion coating is greater than 0.5mm, the leakage detection voltage is calculated according to formula (1): U-7843T
When the thickness of the anti-corrosion coating is less than or equal to 0.5tmm, the leakage detection voltage is calculated according to formula (2): A
Where:
U-3 294/T or U-5000T
---test voltage, in volts (V);
---average thickness of anti-corrosion coating, in millimeters (mm); 7843,3294,5000---infinite constant, GB/T 31404-2015
5.3.5.2 After inspection, anti-corrosion components shall not be stored in the open air for a long time. If they are stored for more than 3 days, they shall be inspected and repaired in time. 5.3.5.3
Wire fly:
Special pads and slings shall be used for anti-corrosion components during loading and unloading, storage, movement, transportation and installation. It is strictly forbidden to use bare steel. Before installation, the integrity of the corrosion-resistant coating shall be checked and the damaged parts shall be repaired. Repair and patching shall use materials compatible with the original anti-corrosion coating and shall not be less than the original anti-corrosion coating. 5.3.5.5 Acceptance shall include at least the following work data: a) The performance of the anti-corrosion coating under the application of the anti-corrosion coating, with a quality inspection report; b) Safety inspection records and acceptance reports of the anti-corrosion coating; d) When there is an operation, the return record shall include the repair location, original method, quantity and inspection results; e) Other related materials. 5.4 Coating maintenance and repair The maintenance of the coating shall be in accordance with the following requirements: Each overhaul shall be inspected once a year; b) For periods less than one quarter, the visible parts shall be inspected visually! C! During the inspection period, the surface of the equipment structure, welding joints, etc. shall be inspected and cleaned frequently. If there are any scratches, etc., the inspection process shall be confirmed and recorded. If there is any corrosion, the strength shall be checked. 5.4.2 Repair of coating 5.4.2.1 The surface treatment shall meet the following requirements: a) The primer shall be polished to the base [meet the St3 grade requirements of B/T8923.2-2008; the primer shall be cleaned of loose coating, and the edges of damaged coating shall be polished to delamination. The colors of each layer of coating shall be similar, and those that cannot be delaminated shall be polished gently; the surface shall be thoroughly cleaned to make it dry, clean and shiny. 5.4.2.2
Before repairing, the following preparations should be made:
New equipment should read the coating matching table, and old equipment should check the previous coating records; h)
The original type, brand and model of coating and the coating that matches or is compatible with the original coating should be selected; the data should be consulted to confirm the temperature and humidity limits of the environment and substrate for the coating used. c
Coating repair should meet the following requirements:
) The repair range should be larger than the damaged surface;
When reapplying primer, small areas should use spraying, and large areas should use spraying; b)
Determine the total dry film thickness, the number of coatings, and the time interval between coatings: After coating repair, pay attention to protection to prevent the wet coating from being stepped on or damaged; for areas that are immersed in water or may be immersed in water, d)
Wait for the coating to become completely dry before immersing in water after coating repair is completed.
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Cathode protection
General provisions
Cathode protection can adopt the sacrificial anode method or the impressed current method. 6.1.2
Disturbance to adjacent structures should be avoided. Pipelines should be equipped with insulation devices to isolate them from other pipelines. 6.1.3
6.1.4 The design and construction of cathodic protection for new nuclear power plants should be carried out simultaneously with the design and construction of the structure and put into use at the same time. 6.1.5 When additional cathodic protection is added during operation, the corrosive environment and corrosion conditions should be tested and evaluated. 6.1.6 In order to ensure that the cathodic protection system equipment can complete its functions under the working conditions that may be encountered, only equipment that has been verified by time and similar operating conditions can be used to ensure that the loss of system function will not affect the normal operation of the protected system. 6:1.7 The connection interface between the auxiliary anode and the reference electrode should ensure no leakage under normal operating conditions. The electrode should maintain its structural integrity, not fall off, and no leakage during and after the extreme safety earthquake vibration (SL-2). The layout of the reference electrode should be able to fully reflect the protection potential. 6.1.8 When the metal material is changed or replaced, the protection criteria, protection current density and protection expansion area of cathodic protection need to be re-determined and calculated.
6.1.9 Cathodic protection components should be resistant to erosion of sediment in seawater. 6.2 Protection potential
6.2.1 For equipment or systems composed of steel plates, cast iron structures, copper alloy pipes, stainless steel, etc., the protection potential should be -0.80V~-1.00V (relative to silver/silver chloride reference electrode, the same below). 6.2.2 For equipment composed of titanium and metals such as steel, cast iron, and copper alloy, the potential of the titanium surface should not be less than -0.75 V. 6.2.3 The protection potential of high-strength steel (base strength not less than 700 MPa) should be between -0.80 V and -0.95 V. 6.2.4 After a long period of power failure (24 h or longer), the potential reduction should be at least 100 mV. 6.3 Protection current density
The protection current density is related to factors such as structural material, operating conditions, surface coating conditions, seawater flow rate, and water quality. The protection current density is selected according to Table 4 during design.
Table 4 Protection current density
Material and surface condition
Equipment name
Trash rack and guide trough
Rotary filter
Seawater pipeline
Secondary filter
Condenser
6.4 Electrical continuity
Steel and cast iron
20~~50
80-100
80-100
80～100
80~~100
Copper alloy|| tt||150~200
6.4.1Electrical connection shall be achieved between each component of the steel structure, and the contact resistance shall be less than 10.6
Titanium alloy
50--60
Unit is per square meter
Stainless steel
150~-200
150~-200
150~200
6.4.2Pipelines and pipeline facilities that are not connected by welding shall use jumper cables or other effective electrical connection methods. 6.4.3For metal structures connected by fasteners, the insulation layer on the connection surface of the fastening parts shall be removed. 6.5 Electrical insulation device
GB/T 31404—2015
6.5.1 An insulating flange shall be provided between the painted cathodic protection pipeline and the non-cathode protection pipeline. The design and installation of the insulating flange shall comply with the provisions of SY/T0516
E.5.2 An escape device shall be installed on the insulating flange. E.6 Sacrificial anode cathodic protection system
6.6.1 Selection of materials
E.3.1.1 The chemical composition and gross chemical properties of the selected sacrificial cathode shall comply with the provisions of G6/T 4348, GB, T 4950, or the electrochemical properties shall be better than those of the operating standards and have been tested; E.6.1.2 For seawater media with different resistivity, the integrated anode shall be selected in accordance with the provisions of GB/T18168: E.6.1.3 For stainless steel with high hydrogen sensitivity, an anode with low drive voltage should be selected. 2.5.2 Determination of structural specifications
The shaft structure and the protected structure shall be coated with epoxy series coatings, and its specifications shall be selected from CET 19166, CE/T 4348, GE, T 4950; e.5.2.2 The structure of the shaft shall comply with the requirements of CE/T4943 and GB/T4950. e.
Details of oxygen protectionbzxz.net
Parameters of protection current meter and so on A.:
6.5.3.2 Calculation of anode water and electricity, see A.2; 6.5.3.3 Calculation of single-plate current, see A.3; 6.5.3.4 Calculation of average current generated by single-point anode, see A.4: 6.5.3.5 Calculation of sacrificial anode quality life, see A.5; E.6.3.6 Calculation of sacrificial anode quantity, see A.6. Acceptance, storage and installation
6.6.4,1 The sacrificial anode shall be provided with factory inspection certificate, chemical composition analysis report and electrochemical performance test report. 6.6.4.2 Sacrificial anodes should be stored in the warehouse, moisture-proof and waterproof, and the working surface of the anode should be kept clean and not contaminated with oil. 6.6.4.3 The installation of sacrificial anodes can be welded or screwed. The installation should be firm and reliable. The coating damage caused by the installation should be repaired with equal quality.
6.6.5 Protection effect detection
6.6.5.1 The protection potential should comply with the provisions of 6.2, and the measurement should meet the following requirements: a) The structures such as trash racks and rotary filters can be measured using fixed and portable reference electrodes; b) Pipes and condenser equipment can be measured using fixed reference electrodes. 6.6.5.2 During shutdown inspection, the equipment surface should be free of rust, and the corrosion products on the anode surface should be sampled and removed. The anode dissolution should be uniform, and the remaining amount can meet the use of one overhaul cycle.
6.6.6 Replacement of sacrificial anodes
When the following situations occur. The sacrificial anode should be replaced: -iiiKAoNhiKAca
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a) Evaluate the anode dissolution rate when the remaining amount cannot meet an overhaul cycle; the anode does not dissolve or dissolves unevenly, and electrochemical and chemical composition analysis should be used to find out the cause; h) [
It has been determined that the potential of the protected structure caused by the sacrificial anode itself does not meet the requirements. c
Impressed current cathodic protection system
6.7.1 System components
The DC power supply shall meet the following requirements:
A constant potential instrument shall be selected;
The performance of the constant potential instrument shall comply with the provisions of CB*3220; b)
The structure, size, shell protection level, color, and inlet and outlet line method of the constant potential instrument cabinet shall comply with the design requirements, c
The auxiliary anode shall meet the following requirements:
The auxiliary anode shall preferably use a titanium-based metal oxide anode, or an auxiliary anode with better performance and passed technical appraisal. a)
The performance of the auxiliary anode shall comply with the provisions of GB/T7388;
The structure and installation method of the auxiliary anode shall comply with the provisions of GB/T7388; The installation structure shall meet the requirements of 6.1.7;
Small-diameter pipelines (less than 1200mm in diameter) should not adopt an embedded structure. d)
6.7.1.3 The reference electrode shall meet the following requirements: The performance of the reference electrode shall comply with the provisions of GB/T7387; a)
b) Silver/silver chloride or zinc reference electrodes can be used in seawater with a resistivity less than or equal to 100α·m; high-purity zinc reference electrodes should be used in seawater with a resistivity greater than 1002·m. For the protection potential of steel in seawater measured by different reference electrodes and their corresponding relationship, see Appendix B;
The structure and installation method of the reference electrode shall comply with the provisions of GB/T7387; e
The installation structure shall meet the requirements of 6.1.7;
Small-diameter pipes (less than 1200 mm in diameter) should not adopt an embedded structure. e)
The shaft grounding device shall meet the following requirements:
A shaft grounding device shall be provided at the end of the shaft of the drum filter as the cathode confluence point of the rotating part of the drum filter;a)
The structure and performance of the shaft grounding device shall comply with the provisions of GB/T17005;b)
The shaft grounding device shall be installed in a watertight junction box. The protection level of the watertight junction box shall not be lower than IP65. The reference electrode measurement grounding point and the cathode confluence point shall not be connected to a set of shaft grounding devices at the same time. d)
6.7.1.5 The cables shall meet the following requirements:
All cables used shall be copper core cables with low-smoke, halogen-free, flame-retardant insulation sheaths. Reference electrodes and measuring cables shall be shielded cables; a)
Cables immersed in seawater shall use seawater-resistant cables. The cables shall be connected to the cathode and the measuring grounding point with waterproof cable connectors. Fasteners shall be made of 316 L stainless steel or more corrosion-resistant stainless steel. Cathode cables and anode cables shall have reasonable cross-sections, and the allowable voltage drop is usually less than 2V; c)
The difference in output current of multiple anodes connected to the same cable shall be less than 10%; the connection between the cable connector and the auxiliary anode and reference electrode shall be reinforced and sealed, and protected by a sealed junction box. e)
System design
The design of the cathodic protection system shall meet the following requirements: Temporary sacrificial anodes shall be designed for corrosion protection of the filter screen in the commissioning room of the nuclear power plant, and the design of the sacrificial anodes shall meet the requirements of 6.6a)
; The protection of coarse screens, reinforcement frames, fine screens and drum filters shall be divided into zone protection, among which the drum filter shall be divided into at least three areas for independent protection in accordance with 6.7.2.2
; The protection of the inner wall of important plant water pipelines shall be carried out by independently protecting the starting section, the last section of the front section of the pipeline and the outlet pipe section of the plate heat exchanger.
The calculation of protection current should meet the following requirements: a)
The calculation of protection current required for the condensate is shown in C.1: b) The calculation of protection area of condenser tube bundle is shown in 6.2: The selection of protection current density is shown in 6.3.
The size, quantity and arrangement of auxiliary anodes should meet the following requirements: The material and structure of auxiliary anodes should be determined first. Then the size and quantity of auxiliary anodes should be determined; a)
The working surface of auxiliary anode should be fully anode rated output. The main performance of commonly used anodes in seawater can be seen in Table C.1; b)
The number and arrangement of blocking electrodes should ensure that the current distribution is uniform and the potential of the protected structure is within the protection potential range;
For the protection of coarse grids, chlorination frames, fine grids and drum filters, hanging anodes should be used. The number of anodes should meet the requirements of uniform protection and system reliability of all components;
For the protection of the inner wall of important plant water pipelines, it should be considered that even if the coating is completely detached, it can still meet the requirements. Protection requirements; For the protection of the condenser, each water chamber is usually equipped with multiple anodes, and the anodes are installed on the water chamber cover; for the protection of the secondary filter, the anodes are installed on the upstream and downstream pipes g)
6.7.2.4 The capacity of the DC power supply shall meet the following requirements: a)
For the calculation of the rated output current of the DC power supply, refer to D.1; b)
For the calculation of the rated output voltage of the DC power supply, refer to D.2: For the calculation of the rated power of the DC power supply, refer to D.3. 6.7.2.5
, the reference electrode shall meet the following requirements:
The installation position of the reference electrode shall be able to detect the most positive and most negative potentials of the protected structure; b) The reference electrode installed on the condenser shall be close to the tube sheet, and the distance from the tube sheet shall not exceed 200mm; The reference electrode installed on the important plant water pipeline shall be able to fully detect the potential of the pipeline, and can effectively monitor the most positive and most negative potentials:
The reference electrode used for the drum filter shall be able to measure the potential of the internal structure and the external structure. 6.7.3 Installation
Electrical continuity shall meet the following requirements:
According to the design requirements, make continuous electrical connections, and the contact resistance shall meet the requirements of 6.4; ay
b) Install the shaft grounding device according to the design requirements, and the performance shall meet the requirements of 6.7.1.4; According to the results of the electrical continuity test, evaluate the construction drawings and structures to determine whether additional electrical connections are required. 6.7.3.2
Insulation performance shall meet the following requirements:
Insulation blue shall be installed on the pipeline, and the performance shall meet the requirements of 6.5! b) The protected equipment rails shall not be electrically connected to the steel bars of the structure. 6.7.3.3 The installation of anode and reference electrodes shall meet the following requirements, and the anode and reference electrodes shall be installed using methods that have been proven by tests or engineering practices; b) Install the anode and reference electrodes according to the design requirements; c) It is strictly forbidden for the anode and reference electrodes to short-circuit with any metal components. 6.7.3.4 The reverse connection of the anode and reference electrode cables shall meet the following requirements: a) Each cathode expansion area shall be equipped with multiple cables connected to the anode and reference electrodes b) The connection mode and installation method of the anode, reference electrode and cable shall be proven to meet the requirements of electrical connection through tests or engineering practice.1; b)
The number and arrangement of the anodes shall ensure that the current distribution is uniform and the potential of the protected structure is within the protection potential range; c)
For the protection of coarse screens, chlorination frames, fine screens and drum filters, suspended anodes should be used, and the number of anodes should meet the requirements of uniform protection of each component and system reliability;
For the protection of the inner wall of important plant water pipelines, it should be considered that the protection requirements can still be met in the case of complete detachment of the coating; for the protection of condensers, each water chamber is usually equipped with multiple anodes, and the anodes are installed on the water chamber cover; for the protection of secondary filters, the anodes are installed on the upstream and downstream pipelines. g)
6.7.2.4 The capacity of the DC power supply shall meet the following requirements Requirement: a)
For the calculation of rated output current of DC power supply, refer to D.1; b)
For the calculation of rated output voltage of DC power supply, refer to D.2: For the calculation of rated power of DC power supply, refer to D.3. 6.7.2.5
, the reference electrode shall meet the following requirements:
The installation position of the reference electrode shall be able to detect the most positive and most negative potentials of the protected structure; b) The reference electrode installed on the condenser shall be close to the tube sheet, and the distance from the tube sheet shall not exceed 200mm; The reference electrode installed on the important plant water pipeline shall be able to fully detect the potential of the pipeline, and can effectively monitor the most positive and most negative potentials:
The reference electrode used for drum filter shall be able to measure the potential of internal and external structures. 6.7.3 Installation
Electrical continuity shall meet the following requirements:
According to the design requirements, make continuous electrical connections, and the contact resistance shall meet the requirements of 6.4; ay
b) Install the shaft grounding device according to the design requirements, and the performance shall meet the requirements of 6.7.1.4; According to the results of the electrical continuity test, evaluate the construction drawings and structures to determine whether additional electrical connections are required. 6.7.3.2
Insulation performance shall meet the following requirements:
Insulation blue shall be installed on the pipeline, and the performance shall meet the requirements of 6.5! b) The protected equipment rails shall not be electrically connected to the steel bars of the structure. 6.7.3.3 The installation of anode and reference electrodes shall meet the following requirements, and the anode and reference electrodes shall be installed using methods that have been proven by tests or engineering practices; b) Install the anode and reference electrodes according to the design requirements; c) It is strictly forbidden for the anode and reference electrodes to short-circuit with any metal components. 6.7.3.4 The reverse connection of the anode and reference electrode cables shall meet the following requirements: a) Each cathode expansion area shall be equipped with multiple cables connected to the anode and reference electrodes b) The connection mode and installation method of the anode, reference electrode and cable shall be proven to meet the requirements of electrical connection through tests or engineering practice.1; b)
The number and arrangement of the anodes shall ensure that the current distribution is uniform and the potential of the protected structure is within the protection potential range; c)
For the protection of coarse screens, chlorination frames, fine screens and drum filters, suspended anodes should be used, and the number of anodes should meet the requirements of uniform protection and system reliability of each component;
For the protection of the inner wall of important plant water pipelines, it should be considered that the protection requirements can still be met when the coating is completely detached; for the protection of condensers, each water chamber is usually equipped with multiple anodes, and the anodes are installed on the water chamber cover; for the protection of secondary filters, the anodes are installed on the upstream and downstream pipelines. g)
6.7.2.4 The capacity of the DC power supply shall meet the following requirements Requirement: a)
For the calculation of rated output current of DC power supply, refer to D.1; b)
For the calculation of rated output voltage of DC power supply, refer to D.2: For the calculation of rated power of DC power supply, refer to D.3. 6.7.2.5
, the reference electrode shall meet the following requirements:
The installation position of the reference electrode shall be able to detect the most positive and most negative potentials of the protected structure; b) The reference electrode installed on the condenser shall be close to the tube sheet, and the distance from the tube sheet shall not exceed 200mm; The reference electrode installed on the important plant water pipeline shall be able to fully detect the potential of the pipeline, and can effectively monitor the most positive and most negative potentials:
The reference electrode used for drum filter shall be able to measure the potential of internal and external structures. 6.7.3 Installation
Electrical continuity shall meet the following requirements:
According to the design requirements, make continuous electrical connections, and the contact resistance shall meet the requirements of 6.4; ay
b) Install the shaft grounding device according to the design requirements, and the performance shall meet the requirements of 6.7.1.4; According to the results of the electrical continuity test, evaluate the construction drawings and structures to determine whether additional electrical connections are required. 6.7.3.2
Insulation performance shall meet the following requirements:
Insulation blue shall be installed on the pipeline, and the performance shall meet the requirements of 6.5! b) The protected equipment rails shall not be electrically connected to the steel bars of the structure. 6.7.3.3 The installation of anode and reference electrodes shall meet the following requirements, and the anode and reference electrodes shall be installed using methods that have been proven by tests or engineering practices; b) Install the anode and reference electrodes according to the design requirements; c) It is strictly forbidden for the anode and reference electrodes to short-circuit with any metal components. 6.7.3.4 The reverse connection of the anode and reference electrode cables shall meet the following requirements: a) Each cathode expansion area shall be equipped with multiple cables connected to the anode and reference electrodes b) The connection mode and installation method of the anode, reference electrode and cable shall be proven to meet the requirements of electrical connection through tests or engineering practice.
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