GB/T 15950-1995 General requirements for environmental radiation monitoring at near-surface disposal sites for low- and intermediate-level radioactive waste
Some standard content:
National Standard of the People's Republic of China
General requirements for envirenmental radiation monitoring around nearsurface disposal site of low-intermediate level radioactive solid waste
GB/T15950-1995
General requirements for envirenmental radiation monitoring around nearsurface disposal site of low-intermediate level radioactive solid wasteSubject content and scope of application
This standard specifies the standard, content and requirements for environmental radiation monitoring at different stages of nearsurface disposal site of low-intermediate level radioactive solid waste. This standard is applicable to routine environmental radiation monitoring of nearsurface disposal site of low-intermediate level radioactive solid waste, and cave disposal site should also refer to it.
2 Reference standards
GB8703 Radiation protection regulations
GB9132 Shallow ground disposal regulations for low- and intermediate-level radioactive solid wastes GB12379 Environmental nuclear radiation monitoring regulations
3 Terminology
3.1 Near surface disposal: refers to shallow buried disposal on the surface or below the surface, semi-underground, with a protective cover, with or without an engineering barrier, and the depth is generally within 50m underground. 3.2 Disposal site: refers to a land-based waste disposal facility area with defined boundaries and under effective control, which consists of a number of disposal units, structures and buffer zones.
4 General provisions
4.1 The environmental radiation monitoring plan for near surface disposal sites for low- and intermediate-level radioactive wastes shall comply with the relevant provisions of Chapters 2, 4 and 7 of GB8703 and GB9132 and GB12379. 4.2 Environmental radiation monitoring of near-surface disposal sites for low- and intermediate-level radioactive waste should be conducted in three stages: before operation, during operation, and after closure.
4.3 The radiation monitoring objectives of the pre-operation stage are to obtain site characteristic data and environmental radiation background levels and their changing patterns. The monitoring objectives of the operation stage are to identify key pathways, key nuclides, and key population groups, and to determine the radiation impact of the disposal site on the environment during operation. The monitoring objectives of the post-closure stage are to check the effectiveness of the containment facilities after the disposal site is closed, and to provide data to estimate the long-term environmental radiation impact. The above monitoring is to provide data for public inquiries. 4.4 The monitoring of the above three stages should be implemented in accordance with the approved environmental monitoring plan. 5 Pre-operation stage
5.1 Observation and collection of natural environmental data
5.1.1 Meteorology
Data such as wind speed, wind direction, atmospheric stability frequency, precipitation, mixing layer height, evaporation, and solar radiation should be collected on site. Approved by the State Environmental Protection Agency on December 21, 1995. 348
Implemented on August 1, 1996
5.1.2 Hydrology
5.1.2.1 Surface water
GB/T15950-1995
The following surface water data should be obtained in the pre-operation stage:
Water system distribution and its characteristic parameters,
Infiltration volume;
Erosion rate;
Surface water discharge rate;
Physical and chemical properties of water,
Physical and chemical properties of water system bottom sediment samples.
5.1.2.2 Groundwater
The following groundwater data should be obtained in the pre-operation phase: a.
Groundwater recharge and discharge;
groundwater flow velocity and direction,
groundwater level and aquifer thickness in the vicinity of the low and intermediate level radioactive waste disposal site and in potentially affected aquifers, and distribution coefficients of relevant elements in groundwater aquifers. d.
5.1.3 Geochemistry and hydrochemistry
In the pre-operation stage, geochemical and hydrochemical data should be collected, including: a.
Composition of major and trace elements (including radioactivity), redox potential and pH (Eh-soil ion exchange capacity,
Partition coefficient of radionuclides with environmental significance between soil and water; leaching rate of important radionuclides in waste and migration rate of leached nuclides. 5.1.4 Ecology
5.1.4.1 Ecological data should be collected in the pre-operation stage, including: a.
Land animals and plant species and growth environment: aquatic species and growth environment;www.bzxz.net
Livestock;
Migratory species, such as migratory birds;
Species endangered and protected. 5.1.4.2
The burrowing rodents and deep-rooted plants present in the site should be specified. 5.2 Collection of social environment data
5.2.1 Population
Based on the natural and social environment, statistical data on the current population distribution and its expected growth within a certain range of the site should be collected, including 5.2.1.1
Population density;
The distribution of residents in the area;
Floating population;
Expected population growth rate,
The diet and living habits of residents.
2Major military, industrial and transportation facilities, as well as schools, hospitals, 5.2.1.2
Distribution of prisons, farms, breeding farms, tourist attractions, etc.
5.2.2 Land
It is necessary to collect information on land use near the site, including: 349
a. Classification of farmland use;
b. Production and consumption of agricultural products.
GB/T15950-1995
5.3 Investigation of background radiation characteristics
5.3.1 The level and changes of the background radioactivity in the environment around the site must be investigated as a basis for evaluating the impact of the operation and closure of the disposal site on the environment.
5.3.2 Environmental radiation monitoring in the pre-operation stage includes the measurement of environmental radiation levels and the monitoring of environmental media (air, soil 5.3.2.1 Air sampling points should be located at representative points, with a focus on the dominant downwind direction, but there should be points in all directions around the site. For example: upwind and downwind of the disposal site, points of key population groups, the nearest residential area, and the site boundary. This can continue to apply during the operation phase.
5.3.2.2 Surface water sampling points should be located upstream and downstream of (but not limited to) the outlet of the wastewater receiving water body, and at the outlet of the centralized water use point (drinking water and irrigation water for the population).
5.3.2.3 Groundwater sampling points should be taken from monitoring wells around the disposal site. When possible, samples should be collected from agricultural and industrial wells in nearby residential areas and urban areas.
5.3.3 The pre-operation phase survey should obtain at least two consecutive years of data. 6 Operation Phase
6.1 Factors to be considered in environmental radiation monitoring during the operation phase6.1.1 Pathway analysis
Understand the possible migration pathways of waste from the burial site to members of the public and determine the critical pathways for human exposure. The critical pathways depend on the characteristics of waste effluents, the operating conditions of the facility and the environmental factors of the site. Environmental radiation monitoring during the operation phase should also select appropriate locations to collect corresponding environmental samples based on the critical pathways.
6.1.2 Key radionuclides and key population groups
It is necessary to understand the characteristics of the waste buried at the disposal site and determine the key radionuclides. Combined with the pathway analysis, the demographic data obtained in the pre-operation phase and the location, diet, family and occupational habits of the population group are used to determine the key population group. .6.2 Determination of environmental parameters
6.2.1 Meteorological and hydrological parameters
6.2.1.1 Data on wind speed, wind direction and atmospheric stability representing the site area should be continuously observed or collected. 6.2.1.2 The precipitation and evaporation data of the site area should be measured. 6.2.1.3 The groundwater flow rate should be re-evaluated every five years. 6.2.2 Radioactive pollutants
The sampling location, sampling frequency and radionuclide measurement content should be determined according to the specific conditions of the disposal site. 6.2.2.1 Radiation level
High-pressure ionization chambers, scintillation dosimeters and thermoluminescence dosimeters (TLD) are used to directly measure environmental radiation levels. 6.2.2.2 Environmental sampling media
6.2.2.2.1 Air
The location of the aerosol sampling point should be selected based on meteorological data (wind direction) and the location of key population groups. The measurement of radioactive aerosols can be carried out by total alpha, total beta, spectrum or special radionuclide activity analysis measurement methods. The measurement of total alpha and total beta is used to screen whether special radionuclide analysis is to be performed.
6.2.2.2.2 Surface water
Surface water sampling should be carried out in the runoff area around the disposal site. When the discharge directly enters the surface river, it should be monitored at the discharge port and the upstream and downstream of the inflow river. If necessary, other sampling points can be set up for sampling and monitoring during the operation stage. The sample analysis method and requirements are the same as those for groundwater sample analysis.
6.2.2.2.3 Groundwater
GB/T 15950—1995
Groundwater sampling points should be set up above and below the operating disposal ditch or in the water pit of the disposal unit to detect potential leachate from the disposal ditch.
The detection wells around the disposal arm unit are sampled and measured regularly. Total alpha, total beta, and spectrum can be used as radioactive screening items, and special radionuclides can be analyzed when necessary. Non-radioactive parameters, such as pH, conductivity, nitrate, fluoride, total organic carbon, etc., can be used as early warnings to indicate potential problems. 6.2.2.2.4 Soil and Sediment
Soil and sediment sampling should be carried out at key population groups or significant locations around the disposal site. Special consideration should be given to the downwind direction of the dominant wind direction, the area of maximum impact (as determined earlier), the runoff area, the outlet (estuary, canal), and the current waste treatment operation area.
Analysis may include: total alpha, total beta, spectrum, and, if necessary, radionuclide analysis. Soil and sediment are generally used as monitoring indicators, which can reflect the impact caused by long-term operation. 6.2.2.2.5 Plants, Crops and Other Indicators Plant and crop samples representing the main species in the area should be collected regularly. Sampling sites should include representative areas that may be affected and background control areas.
Analysis items are the same as those for soil and sediment. These contents can be used as indicators for ingestion pathway impact analysis. In addition, small mammals, game birds, burrowing rats or their fecal pellets, fish, shellfish, milk, etc. can be used as other indicators. 6.2.3 Investigation level and reporting level
Investigation level and reporting level for activity level of important environmental media should be established. 6.2.3.1 Investigation level
This level is defined according to whether the activity concentration of radionuclides in environmental media, or the concentration of chemical indicator, exceeds three times the standard deviation of the corresponding background level. When the investigation level is found to be reached, the following actions should be taken; a.
Review laboratory procedures;
Check for contamination;
Resample;
Radionuclide analysis,
Increase sampling frequency;
f. Expansion of monitoring program.
Investigation level should be related to multiples of background concentration or appropriate share of dose limit. 6.2.3.2 Reporting level
This level is defined as the concentration of radionuclide activity or chemical indicator exceeding or approximately exceeding the management standard. If the management standard is exceeded, the monitoring results and the mitigation measures taken to solve the problem must be reported to the competent authority. 7 Post-closure phase
After the site is closed and the relevant structures and sites are decommissioned, the residual contamination should be removed to an acceptable level to prevent intruders and prevent biological invasion. Groundwater and other monitoring must continue to be evaluated for long-term environmental impacts. 7.1 Groundwater
In the early period after the site is closed, groundwater monitoring during the operation phase should continue. If it has been confirmed that there are no potential problems, the frequency of groundwater monitoring can be gradually reduced with the approval of the review and management department. Analysis of chemical indicators and radioactive substances should continue. If it is known that groundwater reaches the surface and eventually enters streams, rivers and lakes, these water bodies should be monitored. 7.2 Other sampling media
Plants, especially deep-rooted plants, should be collected regularly to determine the absorption of radionuclides. Burrowing animals or their feces should also be collected for analysis to indicate whether the biological barrier continues to be effective. 351
8 Quality Assurance and Quality Control
GB/T15950—1995
8.1 The environmental radiation monitoring plan should include a quality assurance program. The quality assurance program ensures the correct implementation of the monitoring plan throughout the monitoring process and obtains reliable monitoring results.
8.2 The design of the quality assurance program should at least consider the following factors: a.
The quality of equipment and instruments;
The calibration and maintenance frequency of equipment and instruments; the training of personnel;
Through routine analysis of control samples and the application of standard analytical methods, the verification of methods and the traceability of monitoring results to national standards; the document management required to prove that the required quality has been achieved and maintained. Quality control is applied to all steps of the measurement. These steps include: 8.3
Sampling procedures;
Protective measures during sample transportation,
Pretreatment of samples,
Radiochemical separation;
Radioactivity measurement;
Data processing;
Interpretation and evaluation of measurement results;
Report;
Record keeping,
8.4 Quality assurance should run through all stages of environmental radiation monitoring of disposal sites. Additional notes:
This standard was proposed by the State Environmental Protection Administration and China National Nuclear Corporation. This standard was drafted by the Nuclear Industry Standardization Institute. The main drafter of this standard is Gao Mili.This indicates whether the biological barrier continues to be effective. 351
8 Quality Assurance and Quality Control
GB/T15950—1995
8.1 The environmental radiation monitoring plan should include a quality assurance outline. The quality assurance outline ensures the correct implementation of the monitoring plan throughout the monitoring process and obtains reliable monitoring results.
8.2 The design of the quality assurance outline should at least consider the following factors: a.
The quality of equipment and instruments;
The calibration and maintenance frequency of equipment and instruments; the training of personnel;
Through routine analysis of control samples and the application of standard analytical methods, the method is verified, and the traceability of monitoring results to national standards; the document management required to prove that the required quality has been achieved and maintained. Quality control is applied to all steps of the measurement. These steps include: 8.3
Sampling procedures;
Protective measures during sample transportation,
Pretreatment of samples,
Radiochemical separation;
Radioactivity measurement;
Data processing;
Interpretation and evaluation of measurement results;
Report;
Record keeping,
8.4 Quality assurance should run through all stages of environmental radiation monitoring of disposal sites. Additional notes:
This standard was proposed by the State Environmental Protection Administration and China National Nuclear Corporation. This standard was drafted by the Nuclear Industry Standardization Institute. The main drafter of this standard is Gao Mili.This indicates whether the biological barrier continues to be effective. 351
8 Quality Assurance and Quality Control
GB/T15950—1995
8.1 The environmental radiation monitoring plan should include a quality assurance outline. The quality assurance outline ensures the correct implementation of the monitoring plan throughout the monitoring process and obtains reliable monitoring results.
8.2 The design of the quality assurance outline should at least consider the following factors: a.
The quality of equipment and instruments;
The calibration and maintenance frequency of equipment and instruments; the training of personnel;
Through routine analysis of control samples and the application of standard analytical methods, the method is verified, and the traceability of monitoring results to national standards; the document management required to prove that the required quality has been achieved and maintained. Quality control is applied to all steps of the measurement. These steps include: 8.3
Sampling procedures;
Protective measures during sample transportation,
Pretreatment of samples,
Radiochemical separation;
Radioactivity measurement;
Data processing;
Interpretation and evaluation of measurement results;
Report;
Record keeping,
8.4 Quality assurance should run through all stages of environmental radiation monitoring of disposal sites. Additional notes:
This standard was proposed by the State Environmental Protection Administration and China National Nuclear Corporation. This standard was drafted by the Nuclear Industry Standardization Institute. The main drafter of this standard is Gao Mili.
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