GB/T 47512-2026Design requirements for the prevention and control of water intake blockage in nuclear power plants (English PDF)

4.1 General Requirements

4.1.1 The design should meet the requirements of safety and reliability, technical feasibility, environmental friendliness, resource protection, economic rationality and convenient operation and maintenance.

4.1.2 The prevention and control of water intake blockages should adhere to a combination of technical and human measures, as well as a combination of proactive avoidance and interception measures, addressing the root causes of the blockages. Systematic prevention and control measures should be taken in terms of determination, water intake project design, monitoring and early warning, relocation and disposal, interception and cleanup, and operational requirements. Mechanical methods are recommended. Mechanized, automated, and information-based prevention and control measures are used to ensure the safe and stable operation of nuclear power plants.

4.1.3 Through design and operation and maintenance management, under the influence of external events determined by the design basis in the site hazard assessment, important [activities] should be ensured. Ensure the safety of the plant's water intake system; shut down the circulating water pumps if necessary.

4.1.4 Nuclear power plants constructed with multiple reactors should, in conjunction with the requirements of the regional power grid, develop a comprehensive plan for unit response and control in the event of a blockage outbreak. This is to ensure the stability of the power system operation and maintain the normal levels of grid frequency and voltage.

4.1.5 A comprehensive technical and economic comparison should be conducted, taking into account factors such as site characteristics, sources of clogging, overall layout, filtration system and equipment configuration. Eliminate common water intake failure caused by blockage intrusion in multiple units.

4.1.6 Nuclear power plants with multiple reactors should adopt proactive, advance, and unit-specific emergency response measures, and promptly implement manual intervention and reduce circulating water levels. Measures such as reducing the load on generating units in an orderly manner are taken to avoid short-term passive shutdowns of multiple units due to blockages.

4.1.7 The design intrusion intensity of the blockage should be determined comprehensively based on the blockage investigation, historical extreme value amplification, and the load-bearing capacity of the filtration facilities in the pump room. This will be determined and used as the basis for system and equipment configuration.

4.1.8 Water intake projects should have the ability to actively avoid blockages and reduce the entrapment effect of blockages.

4.1.9 The monitoring and early warning design should reflect the principle of early detection and early intervention, and should preferably have forecasting and early warning functions to support nuclear power plant operation and maintenance management decisions. Provide evidence promptly.

4.1.10 DC cooling water supply systems should be equipped with circulating water monitoring and pre-filtration facilities; each independent water intake and open intake channel should be equipped with corresponding monitoring and pre-filtration facilities. Corresponding circulating water monitoring and pre-filtration facilities.

4.1.11 The configuration of circulating water monitoring and pre-filtration facilities and circulating water filtration facilities should be mutually compatible, and the marine interception facilities and... The target functions and interception targets of each land-based interception facility.

4.1.12 The overall layout of the nuclear power plant, the impact on cooling water intake for the nuclear island and conventional island, differences in system and equipment configuration, and investment impact should be considered. Based on factors such as impact, the configuration scheme of the filtration system for the circulating water system and the plant water system should be reasonably determined.

4.1.13 The classification of buildings, systems and equipment related to the prevention and control of water intake blockages should be reasonably determined.

4.2 Requirements for collecting basic data

4.2.1 Hydrological Data When taking water samples from the coast or tidal estuaries, the following information should be collected.

a) Hydrological conditions of the marine and terrestrial areas near the nuclear power plant;

b) Marine hydrological characteristics, including tidal features, current velocity, direction and movement patterns, tidal range and duration of rise and fall tides, and typical tidal levels. Process line;

c) Tsunami and storm surge conditions;

d) The patterns of sediment erosion and deposition in the project area, and the stability of the shoreline;

e) Sediment movement characteristics, including source, quantity, direction of movement, and extent of drifting zones; vertical distribution of sediment content and particle size distribution curves. Bedload analysis, wind and wave-driven sand lifting and rapid sediment deposition;

f) Wave data, including wave heights at different periods at the intake and various engineering points, wave rose diagrams, wave break zone extent, and 100-year wave data. When encountering waves, such as the maximum possible typhoon waves, the corresponding wave rise should be analyzed and explained.

g) Highest tide level, average tide level, lowest tide level, design benchmark high and low water levels, and once-in-a-century high and low water levels, etc.

h) Salinity characteristics, including salinity and the distribution of salinity along water depth at a specified cross section;

i) Water temperature characteristics determined from nuclear power plant site data, including monthly maximum water temperature, average water temperature, minimum water temperature, and specified intervals. The distribution of surface water temperature along water depth, design baseline natural water temperature, historical extreme maximum water temperature, historical extreme minimum water temperature, and global... Predicted increases in water temperature due to global warming, etc.

j) Abnormalities and pollution of seawater quality;

k) Ice formations, ice conditions, and characteristic values, including freezing period, ice thickness, width, ice flow size and corresponding flow velocity, direction, deposition location, and height. Degree, etc.;

l) Current status and planning of the marine environment, etc.

4.2.2 Meteorological Data

4.2.2.1 The following meteorological data and the times of extreme values should be collected.

a) Annual average temperature, extreme maximum temperature, and extreme minimum temperature;

b) Annual average wind speed and maximum wind speed;

c) Wind rose diagram showing the frequency of winds in each direction throughout the year and in each of the four seasons, as well as the frequency of calm winds.

4.2.2.2 The climate characteristics, historical meteorological disasters, typhoons, etc. of the meteorological stations and the area where the factory site is located should be collected and verified.

4.2.3 Blockage Information

4.2.3.1 The protection targets and standards for the blockage prevention and control design of nuclear power plants should be determined, including marine life, floating objects, silt and debris.

4.2.3.2 A special investigation should be conducted on potential blockages such as marine life and floating debris in and around the nuclear power plant, combined with historical data. Comprehensive analysis determines the types, characteristics, and outbreak patterns of marine organisms requiring protection (including temporal and spatial distribution, abundance, etc.), forming a blockage wind. Risk catalog, risk calendar, and abundance, etc.

4.3 Armament requirements of obstruction control facilities against external events The design of water intake blockage prevention and control facilities should ensure that they do not fail due to external events as determined by the site hazard assessment. Impacts on the water intake safety of critical plant water systems. Design-by-the-base external events include blockage intrusion, external flooding, earthquakes, and extreme winds (including...). Natural or man-made events such as wind and waves, and collisions between working vessels.

5.1 Investigation of Blockages

5.1.1 Survey Plan A reasonable blockage investigation plan should be developed during the engineering design phase. The investigation content includes.

a) Investigate the environmental characteristics of the water area, including its geographical location, water depth, hydrodynamics, meteorology, sediment, and topography;

b) Investigate potential blockages in the waters, including river estuaries, coastal vegetation, floating ice, garbage dumps, and offshore aquaculture areas. Clothing situation;

c) If there are any water intake projects in the vicinity, the blockage situation of the water intake projects should be investigated, including the type, quantity, and location of the blockages. Salvage progress, etc.

5.1.2 Survey Methods

5.1.2.1 Overview of Methods The survey methods include data collection, remote sensing observation, and sampling surveys, and it is advisable to conduct the survey by combining one or more of these methods. Sampling surveys are used to quantitatively assess the targets for defense and the characteristics of outbreaks, while data surveys and remote sensing observations serve as supplements.

5.1.2.2 Data Survey The following data should be collected during the data collection process.

a) Within a 30 km radius of the intake, and potentially extending to a 50 km radius, historical marine life and ecology, marine... Data related to environmental quality, meteorology, topography and sediment type, hydrodynamics and flow field analysis, etc.

b) Data on marine disasters such as red tides, green tides, jellyfish blooms, typhoons, and cold waves in the same sea area within the past 10 years;

c) Water intake blockage incidents and their handling methods at similar nuclear power plants at home and abroad in recent years;

d) Data on the mechanisms of explosive proliferation of marine organisms;

e) Information obtained through on-site surveys, consultations, and interviews.

5.1.2.3 Remote Sensing Observation Using satellite remote sensing and drones equipped with sensors, the detection range can be expanded from 30 km to 50 km around the water intake. Within the domain, large-scale, non-contact monitoring, identification, and detection of marine organisms and floating debris that may clog the filtration system are conducted. Record.

5.1.2.4 Sampling Survey 5.1.2.4.1 Scope of Investigation The sampling survey should cover a water area of 20 km centered on the nuclear power plant's water intake, and can be expanded to a water area of 30 km. 5.1.2.4.2 Survey Period and Frequency The sampling period and frequency shall be implemented in accordance with the following provisions.

a) The investigation period should be no less than one year, and the frequency should be no less than six times per year. The frequency should be increased during seasons or months when blockages are more likely to occur. Secondly, surveys of the Bohai Sea and the northern Yellow Sea should cover the glacial period.

b) For water bodies with large volumes of runoff, straw, or floating debris flowing into the sea, surveys should cover both typhoon and heavy rain periods;

c) For waters with large tidal ranges, surveys should cover the period of spring tides;

d) For waters prone to large algae outbreaks, surveys should cover the seedling stage, peak growth stage, and shedding stage;

e) For waters prone to outbreaks of small shrimp and jellyfish, water intake blockages should be addressed by considering the reproductive and migration habits of these species. To mitigate the impact of explosive proliferation, the frequency of surveys should be appropriately increased during periods of rapid growth, and based on the migratory habits of marine organisms and their influencing factors, for example... The survey period and duration are determined by factors such as seasonal changes, solar terms, tides, and day-night cycles.

6.1 General Provisions

6.1.1 It is advisable to conduct water intake and entrainment numerical tests during the project feasibility study phase, taking into account site conditions such as tidal dynamics, topography, and blockage characteristics. Simulation and/or physical simulation studies comprehensively investigate biological conservation, the number of water intakes, the location of water intakes, the direction of water intakes, the type of water intake, and the extraction process. Factors such as water flow velocity and breakwater layout should be considered when adopting an active water intake scheme with good guidance effect to reduce water intake entrainment effect.

6.1.2 It is advisable to combine numerical simulation and/or physical simulation methods to conduct water intake flow field analysis, obtain the intrusion path and accumulation trend of blockages, and make appropriate adjustments. Properly set up guidance facilities to actively defend against and guide obstructions.

6.1.3 The location and layout of the water intake shall be in accordance with the following provisions.

a) The water intake location should be chosen in an area less affected by blockages, avoiding major marine spawning areas, feeding areas, and areas where organisms cross waterways. Fishing-sensitive areas such as wintering grounds and migration routes;

b) The locational relationship between the nuclear power plant's self-built wharf and the cooling water intake channel should be determined through a comprehensive technical and economic analysis, and when conditions are suitable, Self-built docks and cooling water intake channels should be constructed separately.

6.1.4 The design of open channel water intakes shall be carried out in accordance with the following provisions.

a) The direction of the water intake should be compatible with the tidal current direction of the sea area after the project is constructed. For reciprocating current sea areas, the water intake direction should preferably be compatible with the rising tide direction. The directions of high tide and low tide are perpendicular, which can be determined through numerical simulation or physical simulation experiments if necessary.

b) Rationally determine the relationship between the water intake direction and the directions of strong and normal waves. Effective wave-damping measures should be adopted to improve the operation and maintenance of the interception facilities. Provide good cover conditions, which can be determined through numerical simulation or physical simulation experiments if necessary.

c) The inflow velocity at the water intake should be less than the average tidal velocity of the surrounding sea area and should not exceed the sediment velocity of the surrounding sea area. The average starting flow velocity. Based on the water intake entrainment model test, it is advisable to select an intake flow velocity with low water entrainment effect.

6.1.5 The design of open intake channels shall be carried out in accordance with the following provisions.

a) Under the influence of a once-in-a-century high tide and once-in-a-century waves, the effective wave height at the first net equipped with a mechanized deployment and retrieval device. It should not exceed

b) The layout design should ensure smooth water flow and reduce ineffective and swirling water areas in open channels, harbor basins, and pump house forebays;

c) The flow pattern of water in the open channel should be such that the intercepting net can maintain a good deployed posture;

d) Open channel guide embankments equipped with interception nets and monitoring and early warning facilities should be able to accommodate vehicle traffic as well as water and power supply.

6.2 Research Content and Methods of Water Intake and Entrainment

6.2.1 The entrainment effect of water intake on blockages should be addressed using numerical simulation and/or physical simulation techniques to analyze the number, location, and level of water intakes. A comprehensive study was conducted on the surface and vertical layout, intake orientation, intake flow velocity, and flow field to optimize the water intake project design and reduce the impact of water intake. The entrainment effect of blockages.

6.2.2 For the renovation and expansion of nuclear power units, it is advisable to obtain historical data on blockage intrusion of operating units, and analyze high-risk areas and outbreaks of blockages. The source was determined and simulated in a simulation experiment.

6.2.3 The motion laws of tracer particles and tracer substances used in numerical simulation and physical simulation should be consistent.

6.2.4 The research content and methods for water intake and entrainment are detailed in Appendix B.

7.1 General Provisions

7.1.1 Monitoring equipment should be configured to monitor and analyze outbreaks or large-scale accumulations of blockages, enabling early detection and identification, and providing a basis for the management of blockages. The implementation of prevention and control measures provides response time.

7.1.2 Based on the site conditions, type and characteristics of the blockage, appropriate monitoring methods should be set up in different areas, and the type and specifications of monitoring devices should be carefully considered. The monitoring should be carried out by comparing different layout methods and selecting representative locations.

7.1.3 It is advisable to utilize existing marine or land-based monitoring equipment and data from national, governmental, and other marine environmental monitoring agencies for implementation. Collaborative monitoring to expand the monitoring scope of nuclear power plants.

7.1.4 A monitoring and early warning platform should be established. Important information from the monitoring and early warning platform should preferably be sent to the main control room, and a local control room should preferably be set up to monitor and warn of the information. Information is centrally monitored.

7.1.5 During the operation of nuclear power plants, risk level assessment standards and monitoring and early warning systems should be continuously improved based on operational data.

7.2 Monitoring

7.2.1 Monitoring Scope The monitoring area for blockages should ideally include the open sea (at least 10 km around the intake), the intake channel, and the pump house forebay, depending on the specific circumstances. The findings of water entrainment research should be used to deploy monitoring equipment in high-risk areas and along intrusion paths of blockages.

7.2.2 Monitoring Methods It is advisable to choose one or more monitoring methods. Common monitoring methods include.

a) Fixed monitoring. Fixed obstruction monitoring equipment installed using buoys, lifting mechanisms, etc., including acoustic monitoring and optical monitoring. Measurement, etc.;

b) Mobile monitoring. Detecting obstructions using mobile monitoring equipment, including unmanned underwater vehicles or vessels equipped with acoustic, optical, and other monitoring devices. Testing equipment;

c) Remote sensing monitoring. Monitoring the movement and distribution of large-scale floating objects, ice floes, and other obstructions on the water surface through radar, satellite remote sensing, etc.

d) Sampling and monitoring. Monitoring is conducted through fixed-point sampling. For monitoring benthic organisms, bottom-trailing nets are recommended. sampling.

7.2.3 Monitoring Elements Monitoring elements should include.

a) Blockage information. Monitoring the distribution and migration path of blockages, such as blockage type, size, distribution density, and distribution area. Area and distribution location, etc.;

b) Hydrological and meteorological information, monitoring parameters closely related to the status and operation of interception facilities, such as wind speed, wave height, etc. Tide levels, current velocities, etc., and also include access to external data such as typhoons and sea ice;

c) Seawater quality information. Monitoring key water quality parameters that characterize marine life growth, such as water temperature, salinity, nitrogen, phosphorus, and leaf temperature. Chlorophyll, dissolved oxygen, pH value, etc.;

d) Status information of interception facilities, such as the stress on the interception net, the attitude of the interception net, the integrity of the interception net, the blockage status of the interception net, and the status of the filtering equipment. Differential pressure, system flow rate, and pressure, etc.;

e) Clog maintenance information, such as the amount of clogs in the filter backwash drainage, the amount of clogs cleaned from the interceptor screen, and the amount of manual retrieval.

7.3 Early Warning

7.3.1 Early Warning Indicators Early warning indicators should be based on the hydrological and meteorological conditions of the water intake area, blockage survey data, interception and filtration system configuration, and trends of monitoring elements. Based on comprehensive settings including automation and operational experience data, the following items should be set with early warning or alarm values.

a) Intensity of blockage intrusion, for typical blockages, such as krill, jellyfish and red tide algae;

b) Status of the interception facilities, such as the tension of the interception net cables, the differential pressure of the filtration equipment, the system flow rate and pressure, etc.

c) Operation and maintenance data, such as the amount of blockage in the backwash drainage of the filter. For hydrological and meteorological data, seawater quality, etc., corresponding early warning or alarm values can be set for indicators closely related to marine life outbreaks, such as... Severe weather, wind, water temperature, chlorophyll, etc.

7.3.2 Early Warning Classification The decision should be based on the type, quantity, growth trend, and impact on water intake blockage of the obstruction, combined with the interception and clearing capacity of the interception facilities and their historical performance. Based on historical data collection and salvage, different risk warning levels should be established, and each risk level should have a targeted response action. Risk warning levels are divided into three levels.

a) Level 3 warning. The number of obstructions has increased, exceeding the historical normal level;

b) Level 2 warning. A large amount of blockage triggers the fine screen differential pressure alarm, the circulating water filtration facility filter screen differential pressure alarm, etc.

1 Warning. Detection of blockage outbreaks or resulting in breakage or damage to the filter screen, leading to a sustained differential pressure on the circulating water filtration system. High pressure differential alarm for filters in high-efficiency and plant water systems, etc.

7.3.3 Prediction and Assessment The monitoring and early warning platform should have the function of predicting and assessing blockages, predicting factors such as hydrodynamics, temperature, and salinity, and combining this with the water intake. Monitoring information on blockages in nearby waters allows for dynamic prediction and assessment of the growth, development, migration paths, and outbreak risks of these blockages.

7.4.1 General Provisions

7.4.1.1 The selection of monitoring equipment should be carried out based on the marine environmental conditions of the nuclear power plant, the characteristics of the blockages, and the maturity of the monitoring equipment. For new monitoring equipment, it is advisable to adopt a pilot application and gradual promotion approach.

7.4.1.2 Equipment installed outdoors and underwater shall meet the operating conditions for ambient temperature, wind, and seawater environment. Underwater equipment shall be waterproofed. Measures such as corrosion prevention and prevention of marine organism attachment.

7.4.1.3 The data from the monitoring equipment should be reliable and can be stored for a reasonable period of time. Data from abnormal periods should be exported and saved.

7.4.2 Sonar When using sonar to monitor, identify, and count obstructions, the following regulations shall be followed.

a) Select suitable installation locations and determine the monitoring range based on water depth and equipment performance. The monitoring range should cover the main paths of blockage intrusion and... cross section;

b) It has remote control capabilities and 24/7 uninterrupted monitoring capabilities;

c) It can output images of blockages in real time. After processing, the images can display and reflect information such as the number and location of blockages.

7.4.3 Sea Surface Monitoring Radar When using marine surface monitoring radar to monitor, identify, and count obstructions such as sea ice, oil spills, and floating debris, the following regulations shall be followed.

a) Determine the monitoring distance comprehensively based on the characteristics of the water intake project, the speed of blockage movement, and emergency response time requirements;

b) It has remote control capabilities and 24/7 uninterrupted monitoring capabilities;

c) It has the functions of automatic identification (size, density, distribution, moving speed and direction, etc.) and tracking of target objects;

d) It has wave measurement capabilities, including wave height, wave direction, and wave period;

e) It has the capability to measure ocean currents, including current velocity and direction;

f) It can output information such as the location, size, and distribution of blockages.

7.5 Monitoring and Early Warning Platform

7.5.1 Data from monitoring equipment, manual monitoring, and salvage operations should be connected to the monitoring and early warning platform.

7.5.2 The platform should have the following functions.

a) Collect monitoring data from monitoring equipment;

b) Storage, processing, and visualization of monitoring data;

c) Equipment management, monitoring, forecasting, early warning, recording, risk calendar and blockage management, electronic control of manual inspection data, etc.;

d) Establish an information exchange channel with the main control room based on the management needs of the nuclear power plant.

7.5.3 The monitoring and early warning platform should be staffed.

9.1.1 General Provisions

9.1.1.1 Appropriate interception, cleanup, and relocation facilities should be configured based on the nuclear power plant's identified blockage risk list and outbreak intensity, including... The various facilities specified in

9.1.1.2 The design of pre-filtration facilities should adopt a 100-year flood control standard, enabling interception functions both during 100-year flood high and low tide levels; The recurrence period of waves should be considered as once in a century.

9.1.1.3 The layout of pre-filtration facilities should be adapted to the tidal dynamics, flow patterns, and wave characteristics of the location. If necessary, it can be achieved through a model. The model test determines the positional relationship between the pre-filtration facility and the water intake building (structure).

9.1.1.4 The design of the interception net should be considered in conjunction with the technological design of the net and the conditions of the location, such as waves, water depth, current velocity, wind, silt, and obstructions. Stress assessment of the interception network provides a basis for facility operation and maintenance and equipment selection.

9.1.1.5 The number of interception nets and the length of the mesh should be determined based on the type and characteristics of the obstruction, the intensity of the intrusion, and the interception efficiency of each level of interception facilities. The interception and cleaning capabilities of the circulating water filtration system are comprehensively determined.