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This standard is developed in accordance with the rules given in GB/T 1.1-2009.
Method for monitoring individual dose induced by radon and its progeny
1 Scope
This standard specifies the method for monitoring individual dose induced by radon and its progeny using solid state nuclear track detection technology.
This standard is applicable to monitoring of individual dose induced by radon and its progeny in workplaces such as uranium mines, non-uranium mines and underground culverts.
2 Normative References
The following referenced documents are indispensable for the application of this standard. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GBZ 129 Specifications for individual monitoring of occupational internal exposure
3 Terms and definitions
For the purposes of this standard, the following terms and definitions apply.
3.1
radon
chemical element with atomic number of 86, with main isotopes of 222Rn, 220Rn and 219Rn
Note: Radon in this standard only refers to 222Rn.
3.2
radon exposure
total amount of radon entering human body through air exposure in a certain period of time
Note: Its unit in the international system of units (SI) is Becquerel hours per cubic meter (Bq·h·m-3).
3.3
solid state nuclear track detection
charged particle detection method which is established based on the phenomenon that the charged particles will cause atomic-scale radiation damage along their tracks as they pass through an insulating medium. If the damage density is high enough, it will be treated by methods such as chemical etching and may be observed under ordinary microscope.
3.4
CR-39
material with the scientific name of carbonic acid propylene acetic acid, or dially glycol carbonates
Note: It was discovered by chemists of Columbia Company, USA, and is the No.39 material in a series of polymers developed by the US Air Force, so it is commonly known as CR-39.
3.5
chemical etching
process of chemically etching damage of solid state nuclear track detector to form an observable track
3.6
radon dosimeter
device which may be worn on an individual and used for monitoring the individual dose induced by radon and its progeny
Note: Radon dosimeter in this standard refers to dosimeter composed of CR-39 element and passive diffusion radon collection cup (box).
3.7
equilibrium factor; F
ratio of the equilibrium equivalent concentration of radon to the actual concentration of radon
Note: Equilibrium equivalent concentration is the activity concentration of radon when it is in equilibrium with its short-lived progeny and has the same α potential concentration as the actual non-equilibrium mixture.
3.8
follow up dosimeter
device which is used to measure synchronous radon exposure in non-occupational workplaces (including dosimeter mailing), which shall deducted from individual dose of radon and its progeny
4 Monitoring principles
4.1 Routine monitoring of individual dose induced by radon shall be carried out when the individual dose induced by radon exposure due to occupational reasons is likely to exceed 2mSv/a, which may be judged by combining the active site measurement results and working conditions usually.
4.2 The monitoring period of individual dose induced by radon and its progeny shall refer to the requirements of GBZ 129, and factors such as sensitivity of monitoring methods shall be considered. The monitoring records, reports and archives shall meet the requirements of GBZ 129.
5 Measurement system
5.1 Composition of measurement system
5.1.1 The measurement system for individual dose induced by radon and its progeny is mainly composed of radon dosimeter, chemical etching device and track readout system.
5.1.2 The radon collection cup (box) of radon dosimeter shall be made of conductive plastic, and a radon collection chamber of suitable size shall be set aside, and a wearing needle (clip) shall be set on the outside for easy wearing and use. See Annex A for the schematic diagram for radon dosimeter.
5.1.3 The chemical etching device is composed of constant temperature water bath, temperature control system, etching rack and etching rack container, etc.
5.1.4 The track readout system is composed of an optical microscope and an adaptive image analysis system.
Foreword i
1 Scope
2 Normative References
3 Terms and definitions
4 Monitoring principles
5 Measurement system
6 Radon exposure measurement
7 Dose estimation
8 Analysis of uncertainty
9 Quality assurance
Annex A (Informative) Structure diagram of radon dosimeter
Annex B (Informative) Detection limit of solid state nuclear track measurement method
Annex C (Informative) Conversion coefficient from unit radon exposure to radon effective dose
Annex D (Informative) Examples of uncertainty evaluation for monitoring of individual dose induced by radon and its progeny
Bibliography
