GB 5294-2001 Occupational exposure personal monitoring specification External exposure monitoring
Some standard content:
1 General Principles
National Standard of the People's Republic of China
Methods of personnel dose manitoring for radiation workers
UDC614.888.5
GB 5294—85
1.1 This method is formulated to implement GB4792—84 "Basic Standard for Radiation Health Protection" and "Regulations on the Management of Personal Dose Monitoring for Radiation Workers" and to ensure the quality of personal dose monitoring. 1.2 This method is applicable to all radiation work units and serves as a technical specification for personal dose monitoring professionals. 2 Monitoring Methods
2.1 Workers who receive external radiation generally only need to wear a personal dose meter on their chest. If the left chest is shielded by protective equipment such as a lead apron, the dose meter should be worn outside the lead apron or on the left collar. When a certain part of the body may be exposed to greater radiation, a personal dose meter should also be worn at that part for monitoring. 2.2 When working in a complex situation with several radiations, and the dose contribution of each type of radiation cannot be ignored, it is necessary to wear a combined dosimeter that can measure these types of radiation.
2.3 In a mixed field of X-rays and neutrons, when the neutron dose equivalent may exceed 10% of the X-ray dose equivalent, it is necessary to wear a combined personal dosimeter that can measure both X-rays and neutrons. 2.4 When the radiation field is not uniform, it is recommended to conduct dose evaluation for workers, and plan to wear dosimeters on the corresponding body surface parts of major organs of the body, or conduct special monitoring of the radiation field. 2.5 When occupational personnel may receive planned emergency exposure due to special needs, they should wear direct-reading or alarm-type personal dosimeters to prevent exposure exceeding the predetermined limit during operation. 2.6 Air samplers are usually used for sampling and monitoring of air pollution. The samplers should be set at some pre-selected positions so that they can reasonably represent the breathing zone of the workers. When working in a standing position, the breathing zone can be 1.5m above the ground, and 1m is appropriate if necessary.
2. Generally, the analysis of excrement is used to monitor internal radiation. Units with conditions can use the method of direct in vitro mouse measurement to monitor radionuclides.
2.8 The reading cycle of the external radiation personal dose meter and the frequency of routine internal radiation monitoring can be reasonably selected by each unit according to specific circumstances. The reading cycle of the external radiation personal dose meter is generally recommended to be 30 days, which can also be extended or shortened depending on the specific circumstances. 2.9 Under normal circumstances, when using the direct measurement method to detect surface contamination, the distance between the probe contaminated with radioactive substances and the contaminated surface shall not exceed 0.5cm, and the speed of the probe moving on the contaminated surface shall be consistent with the requirements of the instrument used. The distance between the probe contaminated with β-radioactive substances and the contaminated surface is preferably from 2.5cm to 5cm, and the moving speed should match the response time of the instrument used. For the detection of local skin surface contamination, it should be determined by the average measurement over an area of approximately 100 cm, and this should be used as the basis for the evaluation of the dose equivalent. 3 Evaluation method
3.1 When the personal dose monitoring value of the radiation worker is lower than the annual dose equivalent limit, the result of the personal dose monitoring can be directly used as the annual dose equivalent for evaluation.
3.2 The dose equivalent is calculated according to formula (1).
Promulgated by the Ministry of Health of the People's Republic of China on November 1, 1985 and implemented on December 1, 1985
Formula: Q
GB 5294—85
-The effective value of the quality factor, the approximate value of Q is shown in Table 1. N-The product of other correction factors.
-In general, N= 1
X-rays: X-rays and electrons
thermal neutrons
energy unknown, mass unknown, and stationary single-charged particles with unknown energy units (as well as particles with unknown charge numbers) 1
3.3When the personal dose monitoring value of radiation workers is equal to or greater than the annual dose equivalent limit, the following methods can be used to process the clinical test results according to the needs of the evaluation.
3.3.1The dose equivalent (H) of the main organs is calculated according to formula (2). H=C.Hs
Formula: C is the conversion coefficient from the skin dose equivalent (Hs) of the wearing part of the personal dosimeter to the organ dose equivalent. Its value is generally measured by phantom, and can also be calculated by theoretical methods. 3.3.2The whole body effective dose equivalent (H) is calculated according to formula (3). He -ZW.Ht
Where: -
Organ (T)
→The weight of the corresponding organ is wide, and its recommended value is shown in Table 2. Table 2
Red bone marrow
Gland
Bone surface
(3)
Other organs*
*Other organs refer to the glands, breasts, red bones, lungs. In addition to the thyroid gland, bone surface, the other 5 organs that receive the dose or the largest, each organ W1=0.06, skin, lens, foot, ankle, neck and forearm should not be included in other organs, and the digestive tract can be regarded as four organs (i.e., stomach, small intestine, upper large intestine and lower large intestine)
3.4When the annual intake can be estimated. The value of Appendix C can be used to calculate the effective dose equivalent of internal radiation, or it can be approximately calculated according to formula (4).
He = 0.05/711.1
Where: ", annual intake of Class-i radionuclides: 11, annual intake limit of Class-i radionuclides. 3.5 When it is difficult to estimate the annual intake, the method in Appendix B can be used to estimate organ dose and effective dose equivalent. (4)
3.6 In the case of combined internal and external irradiation, in principle, the effective dose equivalent of the two should be added together. When it is lower than the annual dose equivalent limit, the clinical test results of the external irradiation personal dose meter can be added to the estimated value of the internal irradiation effective dose equivalent. 3.7 The use of a wide sampler If the actual inhalation amount of the staff is estimated by the measurement results, the conversion coefficient should be determined by experimental methods. If there is no such experimental data, a certain multiple (usually 10 times) of the fixed sampler can be taken as the estimated value of personal air sampling to estimate the inhalation amount.
GB5294-85
3.8 The uncertainty in the "Regulations on the Management of Personal Dose Monitoring for Radiation Workers" refers to the range of deviation from the mean under a certain confidence limit level. It is generally obtained by the ratio of the uncertainty value to the mean value at a 95% confidence limit level and expressed as a percentage. 8.9 The total uncertainty in the "Regulations on the Management of Personal Dose Monitoring for Radiation Workers" only includes the inherent error of the dosimeter and the error introduced by the scale due to changes in radiation field characteristics, and does not include the error of deriving the dose from the measurement results. 4 Monitoring Records
4.1 At the beginning of personal dose monitoring, a summary of the dose received by the radiation worker in the past should be made, and this summary should be attached to the personal dose file of the person. This summary should include the work unit, start and end dates, nature of work, irradiation conditions, personal cumulative dose (rough estimate), etc. The personal dose file uses the format of Table A1. 4.2 External exposure personal dose monitoring should be recorded in the format and content of Table A2, and internal exposure personal monitoring should be recorded in the format and content of Table A3.
4.3 When the monitoring results of personal dose of external radiation are suspicious, the exposure situation should be investigated, and the investigation results should be attached to the corresponding personal dose monitoring records. The following items should be recorded: monitoring period and abnormal conditions during the monitoring period (for example, accidental exposure of personnel, etc.) 3a.
b. Abnormal conditions of the operation of the subordinate personnel;
Monitoring results of the radiation field:
Conclusion of the investigation:
Signature of the investigator:
When using the simulation measurement results of the workplace to estimate personal dose, the following should be recorded:a.
Irradiation period;
Workload during this period:
Unit workload (one operation) Dose value received by the staff: Correction data of various factors affecting the dose: Simulation experimental conditions:
Estimation results;
Signature of the investigator.
In the dose file of the staff who have not received personal dose measurement: there should be records of regular monitoring results of the workplace. 4.5
4.6 When estimating internal contamination by the amount of inhaled airborne radioactive substances and exposure time, the following records should be recorded and attached to the personal dose file.
Methods for estimating internal contamination;
Concentration of airborne radioactive substances, exposure time and breathing volume; Determine the correction values of various factors that affect the measurement and estimation results: d.
Estimation results;
Signatures of monitoring and estimation personnel.
Accident exposure records should include the following: Time and place of the accident:
Case of the accident (including the relative position of the source horse and the exposure room, etc.) b.
Accident causes and treatment measures:
Dose estimation method and results. When simulation measurement is required, the simulation conditions and methods shall be recorded in detail; e.
Records of various correction factors used in dose estimation: Establish radiation accident files.
5 Monitoring instruments
GB 5294-85
5.1 Appropriate personal dosimeters should be selected according to the size of the monitored area, object and monitored population. 5.2 Various personal dosimeters should have appropriate lower reading limits and detection valves. Generally speaking, the requirements for the lower reading limit (RL) can be determined according to formula (5):
Rr= 0.1LT /365
Where: T measurement cycle, days;
Corresponding years.
5.3 Within the energy range used, the energy response of the personal dose meter should be within ~20-40. The response of the personal dose meter should be within ±30%,
5.4 In the confidence limit of %, the uncertainty of the personal dose under experimental conditions should not be greater than 0.3 times the mean value of the test, and the uncertainty of the monitoring result should not be less than 0.5 of the monitoring mean. 5.5 The monitoring instrument for the site of Y (or X) ray operation should have appropriate sensitivity, and should also have the mark of the center of the sensitive volume of the ionization chamber, and should have appropriate scale units (for example: nR/h), and the inherent error of the instrument should be less than ±20%. 5.6 The personal dose meter must be calibrated with a reference radiation source before use, and the accuracy of the reference source should be within ±5. 5.7 The personal dose monitoring method should be regularly compared by the technical responsible unit designated by the Ministry of Health, and the site monitoring instrument should be calibrated at least once a year by the secondary benchmark laboratory. The detectors that have been stored for a long time or repaired should also be re-verified before use. Name
Unit:
Gender:
Appendix A
Personal dose record of radiation workers
(Supplement)
Table 1 Personal dose file record form for radiation workers Date of birth:
Shipikun dose "*, mS
Participation period of radiation work:
Internal radiation annual effective dose, mSv
, refers to the annual skin dose base (for external (rays, etc.) personal dose), number
Radiation record request situation description
Name:||tt ||Unit:
Test start and end period
Skin dose; mSv
Table A2 Radiation workers external exposure personal dose monitoring record table Gender:
Posterior dose sensitivity Year
Organ name
* Refers to the individual dose of the system, but the ratio of face to skin dose at the wearing position. The device should be appropriate for the dose area, mSv
*Uneven exposure, serious exposure organs need to be monitored, and this monitoring is not required in normal situations***The effective dose is calculated only when the time is zero. Period:
Effective dose***Sensitivity:||tt ||No.:
Type of instrument, status descriptionbzxz.net
Signature of monitor
Unit:
Liangyangshan period
Sample type
Nuclide to be measured
Table, A3 Radiation 1 Worker Internal Exposure Personal Dose Monitoring Record Form:
Description of measurement method
Measurement result*
Intake method
Annual intake of rats, *kBq!
No.:
Effective accumulated dose in ***ms,
Analyst's statement and signature||t t||* The information of the test results shall be based on the content of the test results. For example, if the sample is a substance, the unit price can be calculated by pulse counting (m, L urine); some test results need to be explained, for example, in air sampling, if personal air sampling coupons are not used, it should be explained how many of the fixed sampler monitoring results are used as the personal sample test results. , 0.02mi per minute of inhalation, 2.2kg per person, 2000h per year for professional personnel, and 8760h per year for members of the public. ** Weekly Appendix.
B.1 Calculation method of internal organ exposure dose
GB 5294-85
Appendix B
Calculation method of internal radiation dose
(Supplement)
The internal radiation organ dose (DI, G) is calculated according to formula (B1): Dt =E AkS(TK)
Where: Ak——the cumulative activity in the source organ (K), MBq·h; (B1)
S(-K)—the unit cumulative activity of the source organ (Φ) causing the average cumulative dose absorbed by the organ, Gy·MBq-.h-. The cumulative activity (AR) of the source organ (K) in a certain time interval (t-→t) is obtained according to (B2): Ax (t) dt....
·(B2)
Formula: Ak (1) is the radioactivity of the source organ at time it. The value of Ak (1) can be estimated from the internal irradiation monitoring results. The value of MBq
S (T+K) can be found in the relevant publications of the International Medical Radiation Research Institute (MIRI). It should be noted that the unit of S (T+K) values in these publications is rad·μC,-1. h-1. The values required for this standard can be obtained by multiplying the values of these publications by 2.703x103.
B,2 Calculation method of effective dose equivalent of internal exposure According to the recommendation of the International Commission on Radiation Protection (ICRP), the committed dose equivalent from several source organs is calculated according to formula (B3): H50, T=1.6×1C-1ZZ(UkESEE(T+K)) Where:
Uk——the number of days for the transition of j nuclide in the source organ (K) within 50 years after the ingestion of radionuclides; (B3)
SEE(T→K), the specific effective energy of type i radiation of j nuclide in the source organ absorbed by the target organ and corrected by the quality factor for each transition:
1.6×10-1——the product of the conversion coefficient from megavolt to volt and the conversion coefficient from volt to gram. For any nuclide j, the specific effective energy ShF(T--K) can be obtained according to formula (B4): SEE(T+K)I-EY,E:Ar(T+K),Q, M
—the yield of type 1 radiation at each transition of a nuclide: E, the mean energy or monoenergetic of a certain type of radiation (i) at each transition of a nuclide, MeV: Q: the quality factor of type 1 radiation
A: (T·K), the fraction of type i radiation energy released from a source device (K) absorbed by a target device (T) (abbreviated as energy absorption fraction), which has the same meaning as (T+K) in the MIRL system. From (1) (B1) and (B2), we can get (B5) Hau. T-QNES(T+K) fAk (t)df
, so the committed dose (Hsu: T, S) of the collecting organ (T) can also be calculated using formula (B5). (B5)
GB5294--85
In the evaluation of radiation health protection, the effective dose of internal radiation (to be accumulated) shall be calculated according to formula (B6): Hso,E-EWHso,T
Wherein: Wr—weight factor of each organ, the recommended value is 43.3. (B6)
GB5294--85
Appendix℃
Internal radiation dose estimation table
(Supplement)
C.1 Table C1 lists the effective integral doses of radiation workers at different periods after inhaling 1Bq radionuclides. C2 Table C2 lists the effective integral doses of radiation workers at different periods after inhaling 1Bq radionuclides. C,3 After ingesting radionuclides. Its effective dose shall be calculated according to the following formula. H = D(low LET)/V(high LET)
Formula: D(low LET), D(high LET) - respectively the effective integrated dose of low LET radiation and high LET radiation after taking in a certain radionuclide per becquerel.
C, 4 The effective integrated dose of unit activity after taking in at any time is only for reference in radiation health protection. If high accuracy is required, the method in the appendix should be used for calculation. Table CI effective dose after inhalation of each becquerel of radionuclides absorbed
1 19*a D
1.3×1c\a
1.4>10'aw
Increase
Compounds
Zn2-, Mg3-, Fe3-, B, 3+
and phosphorus compounds of the series elements
All compounds except W
Zn2-, Mg**, Fe3-, H,1+
and phosphorus compounds of chlorinated amines
integration period
all phosphide mediators except special categories
sulfur
oxides and hydroxides
other compounds except Y categories
chemicals, chlorinated amines, chlorinated amines
compounds and salts
other compounds except chlorinated amines
x10-\,Gy'Bq
half-life
7.5×101a
is high
GB 5294 --85
Continued Table C1
Compounds
Oxides, hydroxides and halogens
Compounds
Other compounds except alumina
Oxides, hydroxides and halogens
Compounds
Other compounds except alumina
Oxides, hydroxides and halogens
Compounds
Other compounds except W
Oxides, hydroxides, halogens
Compounds and nitrates
Other compounds except Y
Oxides, hydroxides, halogens
Compounds and nitrates
Other compounds except Y
Oxides, hydroxides, halogens
Compounds and nitrates Oxides, carboxyl compounds and nitrates
Compounds other than Y
Oxides, halides
Compounds other than I
Oxides and hydroxides
Sulfides, halides and nitrates
Other compounds other than W and Y
Oxides and hydrides
Sulfides, halides and nitrates
Other compounds other than W and Y
Oxides, hydroxides, phosphates
Nutrates
Compounds other than Y
Integral dose function of different periods
×10-1, Gy/Bq
Half-life
65000a
Yes
GB 5294--85
Continued Table C1
Compounds
Chromogens, hydroxides, sulfides
and halogen compounds
Other compounds except W
Element selenium, oxides, hydroxides
and carbides
Other compounds except W Other compounds
SrTi, and soluble compounds
Other compounds except class Y
SrTiO, and insoluble compounds
Other compounds except class Y
SrTi0, and insoluble compounds
Other compounds except class Y
5rT10, and soluble compounds
Other compounds except class Y
+×10-\, Gy/Bq
The most effective dose at different times
SrT1O, and insoluble compounds
! 0, 42
Other compounds except Y
SrTi, and insoluble compounds
Other compounds except Y
Oxides and hydroxides
Other compounds except Y
Compounds and hydrides
Other compounds except Y
Oxides, hydroxides
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