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HJ 899-2017: Water quality. Determination of gross beta activity. Thick source method
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Water quality. Determination of gross beta activity. Thick source method
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Basic data | Standard ID | HJ 899-2017 (HJ899-2017) | | Description (Translated English) | Water quality. Determination of gross beta activity. Thick source method | | Sector / Industry | Environmental Protection Industry Standard | | Classification of Chinese Standard | Z16 | | Classification of International Standard | 13.060 | | Word Count Estimation | 16,186 | | Date of Issue | 2017-12-21 | | Date of Implementation | 2018-02-01 | | Quoted Standard | GB 12379; GB/T 11682; HJ 493; HJ 494; HJ 495; HJ/T 61; HJ/T 91 | | Regulation (derived from) | Ministry of Environmental Protection Announcement 2017 No. 77 | | Issuing agency(ies) | Ministry of Ecology and Environment | | Summary | This standard specifies a thick source method for the determination of total beta radioactivity in water. This standard applies to the determination of total beta radioactivity in surface water, groundwater, industrial wastewater and domestic sewage. The lower detection limit of the method depends on the total mass of the residue contained in the sample, the detection efficiency of the measuring instrument, the background count rate, and the measurement time. Under typical conditions, the detection limit can reach 1.5��10^(-2)Bq/L. | HJ 899-2017: Water quality. Determination of gross beta activity. Thick source method---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
(Water quality - Determination of total radioactive β thick source method)
People's Republic of China national environmental protection standards
Water quality - Determination of total radioactive β thick source method
Water quality-Determination of gross beta activity
-Thick source method
2017-12-21 Published
2018-02-01 implementation
Ministry of Environmental Protection released
i directory
Foreword .ii
1 Scope 1
2 Normative references 1
3 Terms and definitions
4 method principle 2
5 Reagents and materials .2
6 instruments and equipment
7 samples .3
8 Analysis Step 4
9 results calculated and said 5
10 precision and accuracy .6
11 Quality Assurance and Quality Control .6
12 Waste treatment .8
13 Matters needing attention .8
Appendix A (informative) Correct use of the standard instructions
Appendix B (Normative) Total α, total β radioactive simultaneous measurement of total β radioactivity concentration correction.14
Foreword
In order to carry out the "Law of the People's Republic of China on Environmental Protection" and the "Law of the People's Republic of China on Prevention and Control of Radioactive Pollution", the protection
Environment, protect human health, standardize the determination of total radioactive β in water, the development of this standard.
This standard specifies the thick source method for the determination of total beta radioactivity in surface water, groundwater, industrial waste water and domestic sewage.
This standard Appendix A is informative appendix, Appendix B normative appendix.
This standard is released for the first time.
This standard by the Environmental Protection Department of Environmental Monitoring Division and Science and Technology Standards Division to develop.
This standard was drafted. Nuclear and Radiation Safety Administration of Jiangsu Province.
This standard verification unit. Zhejiang Provincial Environmental Monitoring Station radiation, radioactive environmental monitoring station in Shanghai, Anhui Province Environmental Radiation Supervision
Governor Station, Jiangsu Provincial Center for Disease Control and Prevention, Tianwan Nuclear Power Station Health and Physical Department and Jiangsu Provincial Radiation Environment Monitoring and Management Station.
This standard MEP approved on December 21,.2017.
This standard since February 1,.2018 come into operation,
This standard is interpreted by the MEP.
1 water quality determination of total beta radioactivity thick source method
Warning. nitric acid, sulfuric acid, acetone and trace radioactive substances used in the experiment are corrosive, toxic and radioactive,
Reagent preparation process should be carried out in a fume hood, operation should wear protective equipment as required to avoid inhalation of respiratory and skin contact
Skin, clothing.
1 scope of application
This standard specifies the thick source method for the determination of total beta radioactivity in water.
This standard applies to the determination of total beta radioactivity in surface water, groundwater, industrial wastewater and domestic sewage.
The method detection limit depends on the total mass of the residue contained in the sample, the detection efficiency of the measuring instrument, the background count rate, the measurement
Time, etc. Under typical conditions, the detection limit of up to 1.5 × 10-2 Bq/L.
2 Normative references
This standard references the following documents or the terms. For undated references, the effective version applies to this book
standard.
GB 12379 Environmental Nuclear Radiation Monitoring Regulations
GB/T 11682 low background α and/or β measuring instrument
HJ 493 Technical Specifications for the Preservation and Management of Water Quality Samples
HJ 494 water sampling technical guidance
HJ 495 water quality sampling program design specifications
HJ/T 61 radiation environmental monitoring technical specifications
HJ/T 91 Technical Specifications for Surface Water and Sewerage Monitoring
3 Terms and definitions
The following terms and definitions apply to this standard.
3.1
Total beta radioactive gross beta activity
Refers to the sample preparation conditions specified in this standard, the maximum β-sample energy greater than 0.3 MeV non-volatile β-radiation
Said.
3.2
Effective thickness of saturated layer
Refers to a radioactive ray emission rate increases with the increase of radioactive material thickness, when the radioactive material thickness reaches a
To a certain extent, the radiation emissivity will no longer increase with the thickness of the radioactive material, and the thickness is the
Effective saturation thickness.
23.3
Thick source method
According to different diameter measuring disc, when the shop thickness reaches the effective saturation thickness of radioactive rays, the corresponding sampling volume
To pave the amount of "minimum sampling volume", this paving method is thick source method.
4 method principle
The sample was slowly evaporated and concentrated, converted to sulfate and evaporated to dryness, and then placed in a muffle furnace to give a solid
Residue. Weigh accurately not less than the "minimum sampling volume" of the residue evenly spread in the measuring plate, placed in a low background α, β measuring instrument
The total β count rate is measured to calculate the total β radioactivity concentration in the sample.
5 Reagents and materials
Unless otherwise specified, the analysis of the use of analytical reagents in line with national standards, experimental water for the newly prepared deionized
Water or distilled water, all reagents should have a lower total beta radioactivity than the method detection limit.
5.1 Nitric acid (HNO3). p = 1.42 g/ml.
5.2 nitric acid solution. 1 1.
Measure 100 ml nitric acid (5.1) and dilute to.200 ml.
5.3 Sulfuric acid (H2SO4). p = 1.84 g/ml.
5.4 Organic solvents.
Absolute ethanol (C2H5OH). purity ≥95%;
Or acetone (C3H6O). Purity ≥95%.
5.5 calcium sulfate (CaSO4). excellent grade pure.
Before use should be dried at 105 ℃ constant weight, placed in a desiccator to save.
5.6 standard substance.
To grade pure potassium chloride as the total β standard material, before use should be dried at 105 ℃ constant weight, placed in a desiccator to save.
6 instruments and equipment
6.1 low background α, β measuring instrument. The main performance indicators should meet the relevant requirements GB/T 11682.
6.2 Analytical Balance. Sense of 0.1 mg.
6.3 adjustable temperature electric hot plate. You can also use electric furnace or other heating equipment.
6.4 oven.
6.5 infrared box or infrared light.
6.6 muffle furnace. to maintain a constant temperature at 350 ℃.
6.7 Measuring disc. stainless steel disc with edge, disc mass thickness of at least 2.5 mg/mm2, measuring disc diameter
Depends on the diameter of the instrument detector and the size of the sample source holder.
6.8 evaporating dish. quartz or porcelain material,.200 ml. Wash pan, dry or in oven (6.4) before use
After drying at 105 ℃, placed in a muffle furnace (6.6) at 350 ℃ burning 1 h, removed after cooling in the dryer weighing, and even
3 The difference between two weighing (interval greater than 3 h, usually not less than 6 h) less than ± 1 mg, is constant weight, record constant weight
the amount.
6.9 Mortar and grinding stick.
6.10 polyethylene barrel. 10 L.
6.11 common laboratory equipment and equipment.
7 samples
7.1 sample collection and preservation
Sample representative, sampling methods and preservation methods according to GB 12379, HJ 493, HJ 494, HJ 495, HJ/T 61
And HJ/T 91 of the relevant provisions of the implementation.
Sampling equipment before sampling to clean, and 3 times with raw water sample polyethylene barrel. After the sample is collected, sample per liter
Add 20 ml nitric acid solution (5.2) Acidified samples to reduce the loss of radioactive material absorbed by the wall. sample
After collection, analysis should be determined as soon as possible, the sample shelf life of generally not more than 2 months. Sampling capacity recommended not less than 6L.
If a clear sample is to be measured, the supernatant can be taken after the suspension is allowed to settle by filtration or standing.
7.2 Sample Preparation
7.2.1 Concentration
Estimate the volume of sample required for experimental analysis based on the residue content (see A.3 in Appendix A). To prevent the operation
The loss in the process, to ensure that the sample is evaporated to dryness, the total mass of the residue after burning slightly larger than 0.1Amg (A is the area of the measuring disc, mm-2)
After burning the total mass of residue by 0.13Amg estimated sample size.
Measure the volume of the sample under test in a beaker, placed on the adjustable temperature hot plate (6.3) on the slow heating, hot plate temperature
Degree control at about 80 ℃, so that the sample was concentrated under micro-boiling conditions. To prevent spillage of the sample during the micro-boiling, beaker
In the sample volume must not exceed half the capacity of the beaker, if the sample size is larger, you can add one after another in succession. All samples are concentrated
To about 50 ml, place the cooling. Transfer the concentrated sample to the evaporating dish (6.8) with a little more than 80 ° C
Hot deionized water to wash the beaker to prevent the salt crystals from adhering to the wall of the cup, and pour the lotion into the evaporating dish together.
For samples with very low hardness (eg less than 30 mg/L in terms of calcium carbonate), measure as much as practicable
The maximum sample volume collected to evaporate and concentrate, if you really can not get the actual amount of sample can also be added to the sample
Slightly more than 0.13A mg of calcium sulfate (5.5), and then evaporated, concentrated, sulfated, burning and other processes made of
Test sample source.
7.2.2 Sulfation
Slowly add 1 ml of sulfuric acid (5.3) to the evaporating dish along the wall of the vessel. To prevent splashing, place the evaporating dish in a red box or
Infrared light (6.5) or water bath on the heating until the sulfuric acid smoke, and then put the evaporating dish temperature adjustable hot plate (6.3) (temperature
Degree below 350 ℃), continue heating until the smoke cleared.
7.2.3 burning
Place the evaporating dish with the residue in a muffle furnace (6.6), ignite it at 350 ° C for 1 h, remove and place it in the desiccator
4 Cooled, accurately weighed after cooling down, and the total mass of the residue after burning determined according to the difference between the weight and the evaporating dish (6.8).
7.2.4 Preparation of sample source
The residue was transferred to the mortar, ground into a fine powder, accurately weighed not less than 0.1Amg of the residue powder to the test
The middle of the pan, with a dropper to draw organic solvents (5.4), dripped onto the residue powder, the infiltration of residual powder in organic solvents
The end of the uniform tile in the measuring plate, and then the measuring plate to dry or placed in the oven drying.
7.2.5 blank sample preparation
Accurately weigh the same mass of calcium sulphate (5.5) as the source of the sample and make it by the same procedure as in the preparation of the sample source (7.2.4)
Blank sample.
7.2.6 laboratory blank sample preparation process
Measure 1 L deionized water to 2 L glass beaker, add 20 ml nitric acid solution (5.2), stir, add
0.13A mg of calcium sulfate (5.5), according to 7.2.1 ~ 7.2.4 operation, and then weighed with the sample source of the same quality of the residue, made of
Laboratory whole process blank sample.
7.2.7 Preparation of standard source
First standard material (5.6) in the mortar fine, accurately weighed sample source of the same quality standards (5.6) in
In the measuring tray, prepare the standard source by the same procedure as in the preparation of the sample source (7.2.4). Dry it and note the date and time of the source.
8 Analysis steps
8.1 Determination of instrument background
Take unused, non-polluting measuring disc (6.7), after washing with alcohol immersion more than 1 h, remove, drying, placed
The low-background α, β measuring instrument (6.1) on the continuous measurement of the total instrument β background count rate of 8 h ~ 24 h, to determine the stability of the instrument background
Sex, taking the average, with the count rate R0 (s-1) said.
8.2 Determination of effective saturation thickness (minimum shop volume)
The actual measurement. Weigh 80 mg, 100 mg, 120 mg, 140 mg, 160 mg, 180 mg,.200 mg, 220 mg,
240 mg of the standard substance (5.6) in the measuring plate, according to the sample source preparation (7.2.4) the same procedure, made of different thickness
The series of standard sources, evenly tiled at the bottom of the measuring plate, after drying, placed on a low background α, β measuring instrument (6.1) on each measurement
The total β count rate of a standard source. Taking the total net β count rate as ordinate and the amount of spreading as abscissa, the β self-absorption curve is drawn. when
When the decking volume reaches a certain value, the total net β counting rate will no longer increase with the increase of the decking volume, and will extend the diagonal of the self-absorption curve
Section and the horizontal section, the intersection of the corresponding bedding shop is the standard source of effective saturation thickness, which is the method of the minimum shop volume.
Theoretical Estimation. If effective saturation thickness measurement difficulties, can be calculated directly by 0.1Amg.
8.3 Blank sample determination
The blank sample (7.2.5) is measured on a low background α, β meter (6.1) for the total β count rate. Total β count rate should be maintained
Within 3 times the standard deviation of the average total background count of the instrument, replace calcium sulfate (5.5) or use a blank test
5-like total β count instead of instrument background count rate.
8.4 The whole process of the laboratory blank sample determination
The total laboratory blank sample (7.2.6) was measured on a low background α, β meter (6.1) for total β count rates. Total β
The counting rate should be kept within 3 times of the standard deviation of the average count rate of the total β background of the instrument, otherwise, the radioactive level should be used more
Low chemical reagents, or use the whole laboratory blank sample total β count instead of the instrument background count rate.
8.5 Determination of standard sources
The total β count rate is measured on a low background α, β meter (6.1) with a standard source (7.2.7) at a count rate of Rs (s-1)
Said, and record count time, time interval and date.
8.6 Determination of sample source
Sample source (7.2.4) Immediately after drying, the total β count rate Rx (s-1) should be measured on a low background α, β meter (6.1)
And record count time, time interval and date.
The length of the measurement depends on the count rate of the sample and the background and the required accuracy. See Appendix A for calculation method
A.1.
Instruments on the same sample source count rate of the existence of fluctuations in the measurement, to be measured more than 5 times, take the arithmetic mean.
9 results calculated and expressed
9.1 Calculation Results
The concentration of total β radioactive activity in the sample Cβ (Bq/L), calculated according to formula (1), the formula derived see Appendix
A in A.7. If the measuring instrument can measure β and α counts at the same time, and α-ray to β-channel can not be neglected,
Daobi correction, correction formula see Appendix B.
02.1
) RR
) RR
C s
0s
0x
(1)
Where. Cβ - total beta radioactivity in the sample concentration, Bq/L;
Rx - total β count of sample source, s-1;
R0 - total background β count rate, s-1;
βs - standard source of total β radioactivity concentration, Bq/g, potassium potassium-40 natural potassium β-radioactivity concentration was 27.4
Bq/g, its radioactivity concentration in potassium chloride is 14.4 Bq/g;
m - sample evaporated, the total mass of the residue after burning, mg;
1.02 - Correction factor, ie 1020 ml acidified sample equivalent to 1000 ml original sample;
Rs - the total source of the total β count rate, s-1;
V - sampling volume, L.
9.2 results indicated
When the measurement result is less than 0.1 Bq/L, keep three digits after the decimal point. When the measurement result is 0.1 Bq/L or more,
6 to keep three significant figures.
10 precision and accuracy
10.1 Precision
Six laboratories performed a total of six washes of a single sample containing total beta radioactivity concentrations of 0.32 Bq/L and 7.98 Bq/L
The relative standard deviations in the laboratory were 2.3% ~ 20% and 3.1% ~ 7.7% respectively. The relative standard deviations
Respectively 8.6% and 7.5%; the repeatability limits r were 0.096 Bq/L and 1.39 Bq/L respectively; the reproducibility limits R were 0.12 Bq/L
And 2.10 Bq/L.
10.2 Accuracy
Six laboratories added potassium chloride to a single sample containing total beta radioactivity concentrations of 0.32 Bq/L and 7.98 Bq/L
Quasi-solution, the recovery rate of the measurement method, the spiked recovery range of 91.4% ~ 111% and 92.2% ~ 108%; spiked
The final recoveries were (97.4 ± 16.6)% and (97.8 ± 12.4)%, respectively.
11 Quality Assurance and Quality Control
11.1 Instrument Stability
11.1.1 Apparatus Poisson distribution test
At least once a year Poisson distribution of the instrument background count test, if the background is very low, available standard activity of a standard source
instead.
Choose a working day or a unit of work (such as the time required to complete one or a set of sample measurements) for the test
Between the interval, in the time interval, measuring 10 to 20 times the same time interval instrument background count, according to the formula (2)
Calculate the value of χ2, compare it with the quantile of the selected significant level in the upper quantile table of χ2 distribution,
Whether the background count satisfies the Poisson distribution.
Sn 22) 1 ( (2)
Where. χ2 - statistics value;
n - the number of background test;
S - n standard deviations of background counts;
The average of N - n background counts is also the variance of the background count calculated as a Poisson distribution.
11.1.2 instrument background, efficiency and quality control
Use a quality control chart to check the stability of the instrument to ensure consistency of routine work.
In the instrument operating voltage and other adjustable parameters are the same circumstances, regular measurement time with a fixed measuring instrument
The background count rate of the instrument and the detection efficiency of the reference source draw the instrument background and the efficiency control chart. Reference source recommended potassium chloride
Standard source (7.2.7) or 90Sr-90Y, 137Cs plating source, plating source active area diameter and diameter of the detector, the general
Not less than φ25 mm, the surface particle emission rate of not less than (102 ~ 103) particles/(min · 2π).
7 background measurement frequency. 1/half a month, the measurement time to take 60 min ~ 240 min, each measured more than 3 times, take arithmetic
Average; efficiency measurement frequency. 1 times/two months, the measurement time to take 5 min ~ 10 min, each measured more than 3 times, take
Average surgery.
When accumulating more than 20 data, the background count rate or instrument efficiency as the ordinate, the date (or measurement order) is
The abscissa and the quality control chart are plotted with control lines (n ± 3σ) and warning lines (n ± 2σ) each marked up and down on average n.
If regularly measured background count rate or efficiency of the instrument in the warning line, then the instrument performance is normal; if the instrument background count rate
Or the efficiency of more than the control line or two consecutive ipsilateral over the warning line, it means that the instrument may not be normal, should promptly find fault
Because; if the measurement results long-term (7 consecutive times) on the side of the average, indicating that the instrument performance system deviation, to be drawn new
Quality control chart.
11.2 Parallel double-like determination
Samples of each batch (≤ 20), randomly selected 10% to 20% of the sample for parallel two-way determination of the number of samples less than
At least 10 pairs of parallel pairs should be measured.
The relative deviation of the parallel double-sample determination results is less than or equal to 30%, and the judgment can also be made according to the formula (3).
) (221 yUyy (3)
Where. y1 - sample measurement results, Bq/L
y2 - parallel sample measurement results, Bq/L;
U (y) - Sample Measurement Uncertainty (95% confidence level), Bq/L.
11.3 spike recovery determination
Each batch (≤20) samples, randomly selected 5% to 10% of the sample, add a certain amount of potassium chloride powder (added
The total activity of potassium chloride shall not exceed 3 times the total activity of the sample) to do spiked recovery determination, the number of samples less than 10, should
Measure at least 1 spike recovery.
Spike recovery rate should be controlled between 70% to 130%, but also in accordance with the formula (4) to judge.
reflab
UU
Xx
E (4)
Where. En-- spike recovery measurement results ratio value;
x - spike recovery, Bq;
X - Scalar quantity, Bq;
Ulab - Laboratory Measurement Uncertainty (confidence level 95%), Bq;
Uref - Uncertainty of added reference substance (confidence level 95%), Bq.
11.4 Laboratory whole process blank sample determination
Each update a batch of reagents required for the whole laboratory blank sample determination. If the measurement of the entire laboratory blank sample
Of the total β count rate in the instrument total β background average count rate of 3 times the standard deviation range, you can ignore, otherwise, you should choose
Lower radioactive reagents or blank sample selection of the total β count value instead of the background value.
812 Waste treatment
Low-level radioactive waste liquid or solid waste generated during the experiment should be collected centrally, uniformly stored, properly labeled,
Commissioned by a qualified unit for processing.
13 Precautions
13.1 The type of radionuclide in the sample to be tested and the chemical composition of the residue after ignition
The same or similar nuclide as a standard source to improve the accuracy of the method, such as. potassium chloride, 137Cs, 90Sr and so on.
13.2 Glassware of the same material shall be used.
13.3 When the salinity of wastewater is high, the measurement sensitivity will be reduced.
13.4 The measurement of the total beta radioactivity in solids can refer to the preparation and measurement section of this standard sample source.
Appendix A
(Informative)
Correct use of the standard instructions
A.1 Measurement time
Measurement time can be estimated according to formula (A.1).
) (ERR
RRR
xx
x
(A.1)
Where. tx-- sample measurement time required, s;
Rx - total β count of sample source, s1;
R0 - total background β count rate, s-1;
E-- predetermined relative standard deviation.
A.2 Sensitivity
Sensitivity depends on the amount of residue in water, the amount of inorganic salts, detector detection efficiency and radionuclide types, different detection
Detector efficiency is given in Table A.1.
Table A.1 detection efficiency of different detectors
Radionuclide beta particle energy (MeV)
Detection efficiency (s-1 · Bq-1)
Proportional counter scintillator counter
40K 1.32 0.44 0.24
90Sr-90Y 0.546 0.40 0.36
137Cs 0.51163 0.29 0.20
A.3 Deviation and lower limit
A.3.1 count standard deviation
The standard deviation sc of the sample activity caused by the statistical error of the instrument count is calculated according to the formula (A.2).
V1000) RR (
02.1m
0s
c
(A.2)
Where. sc-- standard deviation of sample activity concentration caused by counting statistical error, Bq/L;
Rx - total β count of sample source, s-1;
R0 - total background β count rate, s-1;
βs - total β radioactive concentration of standard source, Bq/g;
m - sample evaporated, the total mass of the residue after burning, mg;
1.02 - correction factor, ie 1020 ml of acidified sample corresponds to 1000 ml of original sample;
tx - sample measurement time, s;
t0 - the background of the measurement time, s;
Rs - the total source of the total β count rate, s-1;
V - sampling volume, L.
...
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