GBZ 125-2002 Standard for sanitary protection of instruments containing sealed sources
Some standard content:
Ics13.100
National occupational health standard of the People's Republic of China GBZ125-2002
Health protection standard for gauges containing sealed radioactive source2002-04-08Promulgated
Ministry of Health of the People's Republic of China
Implementation on 2002-06-01
Normative reference documents
Terms and definitions
Radiological protection requirements for source containers
Radiological protection requirements for detection instruments
Radiological protection requirements for production and use of detection instrumentsInspection
Appendix A (Normative Appendix) Schematic diagram of dose equivalent measurement area outside source container
This standard is formulated in accordance with the "Occupational Disease Prevention and Control Law of the People's Republic of China". In case of any inconsistency between the original standard GB16368-1996 and this standard, this standard shall prevail.
Chapters 4 to 7 and Appendix A of this standard are mandatory contents, and the rest are recommended contents. Appendix A of this standard is a normative appendix. This standard is proposed and managed by the Ministry of Health.
The drafting unit of this standard: Beijing Center for Disease Control and Prevention. The main drafter of this standard: Wang Shijin,
This standard is interpreted by the Ministry of Health.
Sanitary protection standard for instruments containing sealed sources
1 Scope
GBZ125-2002
This standard specifies the radiation protection requirements for the production and use of detection instruments (hereinafter referred to as detection instruments) containing sealed radioactive sources (hereinafter referred to as sealed sources).
This standard applies to detection instruments containing sealed sources for intensity measurement. This standard does not apply to detection instruments within the scope of exemption specified in GB13367 "Principles for the Management of Exemptions for Radiation Sources and Practices".
2 Normative referencesWww.bzxZ.net
The clauses in the following documents become the clauses of this standard through reference in this standard. For any dated referenced document, all subsequent amendments (excluding errata) or revised versions are not applicable to this standard. However, parties to an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For any undated referenced document, the latest version applies to this standard.
GB4075 Classification of sealed radioactive sources
General provisions for sealed radioactive sources
GB4076
Radiation protection provisions
GB8703
GB11806
GB13367
GB14052
Regulations on the safe transport of radioactive materials
Principles for the exemption management of radiation sources and practices
Radiation safety performance requirements for isotope instruments installed on equipment 3 Terms and definitions
3.1 Source container
Container for placing a sealed source in the correct geometric position and providing adequate shielding protection to keep the surrounding radiation level below the specified value. The source container may also be provided with a source gate for controlling the on and off of the useful beam and a radiation status indicator. 3.2 Useful beam
Radiation through the window, light bar, conical hole or other collimating device of the source container. 3.3 Sealed source intensity measurement detection instrument An instrument that detects relevant quantities by detecting the change in particle flux when there is or is not a test object, or detecting the flux of secondary particles generated by the interaction between particles and matter, such as a level meter, thickness meter, density meter, hygrometer, nuclear belt scale, etc. 4 Radiation protection requirements for source containers
4,1 The components used to support and accommodate sealed sources must be able to firmly and reliably fix the sealed source and facilitate the assembly and disassembly of the sealed source.
4.2 Under different use conditions, the source container of the detection instrument must meet the safety performance requirements of the corresponding level of source container leakage radiation dose equivalent rate, the highest and lowest temperatures under normal working conditions, the source gate endurance and fire resistance specified in GB14052.
4,3 The source container should have an implicit assembly structure that is not directly visible from the outer surface, or have parts that can only be assembled and disassembled with special tools. 4.4 When the source container is equipped with a beam limiter or source gate, it must meet the following requirements: a. When the detector of the transmission detection instrument is in the use position farthest from the sealed source, the solid angle of the useful beam centered on the sealed source should not exceed the detector without a shield or the shield of the detector, so that the leakage rays passing through the detector or its shield meet the requirements of Table 1.
b. The source gate should be locked in the "open" and "closed" states respectively, and there should be obvious "open" and "closed" state indications. 4.5 Components adjacent to the sealed source should be made of materials with less scattered rays and bremsstrahlung radiation and radiation resistance. 4.6 The shielding design of the source container for ionizing radiation should comply with the optimization principle, so that the leakage rays passing through the outer surface of the source container not only meet the specified dose limit, but also reach "the lowest radiation level that can be reasonably achieved". 4.7 For sealed sources emitting α, low-energy β, and low-energy X-rays, the dose equivalent rate at 5 cm from the boundary column shown in Appendix A (Normative Appendix) shall be less than 2.5 uSv/h. 4.8 For detection instruments other than 4.7, when used in different locations, the dose equivalent rates at 5 cm and 100 cm outside the boundary shown in Appendix A (Normative Appendix) shall meet the requirements of Table 1. Table 1 Locations of use of detection instruments and corresponding leakage radiation control quantities Dose at the following distances outside the boundary
Locations of use of detection instruments
No restrictions on the range of activities of personnel
Few people stay within 1m of the source container It is impossible for anyone to enter the area 3m from the outer surface of the source container, or the radiation workplace has been divided into supervised areas and non-restricted areas Equivalent rate H control value, μSv/h
2.5≤H<25
25≤H<250
250≤H<100 0
It can only be used in specific radiation workplaces and shall be managed in control areas, supervision areas and non-restricted areas.
4.9 The outer surface of the source container must have a firm label and clearly indicate the following: a
Ionizing radiation signs in accordance with GB8703: b)
Manufacturer, date of manufacture, product model and serial number; chemical symbol and mass number of nuclides, activity of sealed source and date of activity measurement; d) Code for the category and safety performance level of the detection instrument in accordance with GB14052. 5 Radiation protection requirements for detection instruments
5.1 Sealed sources must comply with the requirements of GB4075 and GB4076. 5.2 The source container must comply with the requirements of Chapter 4. 100cm
0.25≤H<2.5
2.5≤H<25
25≤H<100
5.3 When it is necessary to transport the sealed source to the outside of the source container by remote control, the detection instrument should: a) have an indicator component that prominently displays the working status of the sealed source on the console and the source container; b) be equipped with a dose instrument that monitors the working status of the sealed source. 5.4 The random documents of the detection instrument must include: a) The documents on the technical characteristics of the detection instrument should list the contents and technical data related to Articles 4.2 and 4.6~4.9; b) The radiation protection inspection certificate of the detection instrument: radiation protection precautions related to the installation, disassembly, maintenance, transportation, storage and decommissioning of sealed sources and source containers, prevention of radiation accidents, emergency response to abnormal events, registration of detection instrument use license, etc.; d) When the detection instrument is in working state, a curve or graph or table corresponding to the dose equivalent rate of 2.5μSv/h. 6 Radiation protection requirements for the production and use of testing instruments 6.1 Selection of sealed sources
Under the condition that the measurement requirements are met, sealed sources with low activity, weak penetration ability and low radiotoxicity should be selected. 6.2 Storage requirements
The storage of sealed sources and source containers containing sealed sources and the temporary storage of source containers containing sealed sources during the installation and maintenance of testing instruments shall meet the following requirements at the same time:
a) Have anti-theft storage conditions and management measures; b) Have shielding protection measures to ensure that the dose equivalent rate at any location that non-radiation workers may reach is less than 2.5μSv/h:
c) There is a conspicuous "ionizing radiation" sign at the storage location. 6.3 Transportation requirements
The transportation of sealed sources and source containers containing sealed sources must comply with GB11806. 6.4: Production requirements
In the following cases, type tests should be carried out according to the radiation protection inspection items specified in Article 7.1; a) before new products are put into production;
b) for products in continuous production, not less than once every two years; c) when production is resumed after an interval of more than one year;
d) when there are major changes in design, process or materials. 6.5 Requirements for use
65, 1: Newly purchased detection instruments must be inspected for radiation protection in accordance with this standard. 6.5.2 At the installation site of the detection instrument, the source container must be firmly and reliably installed, measures must be taken to prevent the loss of the sealed source, and personnel must be restricted from entering the useful wiring harness area between the source container and the object under test. 6.5.3 When it comes to the installation, inspection and maintenance of sealed sources, operators must be familiar with the structure of the source container, master radiation protection skills, and obtain radiation work qualifications. 6.5.4 Retired sealed sources must be strictly managed as radioactive hazardous materials, or returned to the manufacturer or transferred to the retired source storage department, and there must be permanent files.
7 Inspection
7.1 Inspection items
The requirements for the inspection items of the radiation protection performance of the detection instrument are listed in Table 2. 7.2 Test and evaluation methods of source containers
7.2.1 The applicable temperature range, fire resistance test and source gate endurance test of the source container shall be carried out in accordance with the provisions of GB14052. 7.2.2 The applicable temperature of the source container and the source gate endurance test must meet the following requirements after the test: a) the safety mechanism and other relevant components of the source container can still operate normally, and the markings and instructions are still clear; b) the dose equivalent rate around the source container is not greater than 1.5 times that before the test. 7.2.3 After the fire resistance test of the source container, the following conditions must be met: a) In any direction, the dose equivalent rate at 1m from the outer surface of the source container is less than 10mSv/h; b) The sealed source is still in the source container; c) The total surface contamination of the internal components of the source container is less than 2kBq Table 2 Inspection items for the radiation protection performance of detection instruments Requirements Items Clause No. Type inspection Before production After production Factory inspection, user and management department acceptance User and management department verification Structure and working status indication of the source container Source gate endurance |The highest and lowest temperatures applicable to the source container
Fire resistance of the source container
Signage of the source container
Random documents of the instrument
Installation place of the source container
Leakage radiation of the source container when the sealed source is in the storage position
Leakage radiation of the source container when the sealed source is in the working position
Radiation and 2.5uSv/h dose
4.1;4.3~4.5
6.5.4;6.5.5
Cyclic operation for 10
6.4d test
6.4d test
Note: "√" in the table means that inspection is required, and "×" means that inspection is not required. 7.3 Instruments and methods for measuring leakage radiation
Visual inspection
Cyclic operation 10
7.3.1 The measuring instrument shall be suitable for the radiation type, energy and radiation level of the radiation to be measured. Visual inspection
7.3.2 During the type test, the activity of the sealed source in the source container shall be the rated activity value. When the activity of the sealed source is lower than the rated activity, the test result shall be multiplied by the coefficient K. K
Rated activity of sealed source
Activity of sealed source during inspection
7:3:3 When the sealed source is in the storage position (source gate closed), the source container leakage radiation detection points are as follows a) Take the sealed source as the coordinate origin, the useful beam center axis direction as the Z axis, and select the mutually perpendicular X and Y axes in the plane perpendicular to the Z axis. In the positive and negative directions of the X, Y, and Z axes, the detection is carried out at the positions 5cm and 100cm away from the surface of the source container.
b) For transmission instruments with source containers and detectors located on both sides of the object to be measured, when the distance between the adjacent surfaces of the source container and the detector on the useful beam axis is less than or equal to 10 cm, it is not necessary to measure in the area between the two. When the distance is greater than 10 cm, measurement must be performed (see Figure A6 in Appendix A). 7.3.4 When the sealed source is in the working position (source gate is open), the detection of leakage radiation outside the source container should be: a) For transmission instruments, detection should be performed without the object to be measured; b) For scattering instruments, detection should be performed with the object to be measured. The detection points should include: the positions shown in Appendix A: the positions with higher expected doses: the positions where personnel stay for a long time, etc. 7.3.5 For the detection at 5 cm outside the boundary described in 4.7, the recorded reading value should be the average reading value over an area of 10 cm2. For the detection at 100 cm outside the boundary, the recorded reading value should be the average reading value over an area of 100 cm. The distance between the detection point and the boundary should be measured at the center position of the detector of the protective dose measurement instrument. For instruments containing neutron sources, the detection at 5 cm outside the boundary mentioned in 4.7 can be approximated by placing the probe of the neutron protection dose instrument close to the boundary position.
Appendix A
(Normative Appendix)
Schematic diagram of dose equivalent rate measurement area around source container A1 Schematic diagram of dose equivalent rate measurement area around source container of detection instrument Source component
Unit: cm
Figure A1 Schematic diagram of dose equivalent rate measurement area around source container of density meter Unit: cm
One meter at the best distance from the negative measuring head
-1.3cm thick copper screen, its width and height dimensions must be at least 5cm larger than the size of the radiation beam machine surface 100
Schematic diagram of dose equivalent rate measurement area around source container of level meter Figure A3
Chain simple chess batch material
Unit.cm
Thank product head
Schematic diagram of dose equivalent rate measurement area around β, T backscatter measuring instrument Unit cm
Measurement head
Figure A4 Schematic diagram of the dose equivalent rate measurement area around the surface backscatter measuring instrument 100
Measuring disk head
0.6cm original steel plate
Standard cancer scatterer, its size must be at least 5cm larger than the cross-section of the useful beam
2cm original polyethylene
Figure A5 Schematic diagram of the dose equivalent rate measurement area around the backscatter neutron measuring instrument A2 When the distance between the probe of the transmission detection instrument and the adjacent surface of the source container is less than, equal to or greater than 10cm, the equidistant contour line diagram of the dose equivalent rate measurement area around the source container when the source gate is "open" or "closed" is shown in Figure A6. 100
Source component
Source gate closed
Source component
Source in "open position"
Figure A6 Schematic diagram of equidistant contour lines4d test
Note: "√" in the table means that inspection is required, and "×" means that inspection is not required. 7.3 Instruments and methods for measuring leakage radiation
Visual inspection
Cyclic operation 10
7.3.1 The measuring instrument shall be suitable for the radiation type, energy and radiation level of the radiation to be measured. Visual inspection
7.3.2 During the type test, the activity of the sealed source in the source container shall be the rated activity value. When the activity of the sealed source is lower than the rated activity, the test result shall be multiplied by the coefficient K. K
Rated activity of sealed source
Activity of sealed source during inspection
7:3:3 When the sealed source is in the storage position (source gate closed), the source container leakage radiation detection points are as follows a) Take the sealed source as the coordinate origin, the useful beam center axis direction as the Z axis, and select any mutually perpendicular X and Y axes in the plane perpendicular to the Z axis. In the positive and negative directions of the X, Y, and Z axes, the detection is carried out at positions 5cm and 100cm away from the surface of the source container.
b) For transmission instruments where the source container and the detector are located on both sides of the object to be tested, when the distance between the adjacent surfaces of the source container and the detector on the useful beam axis is less than or equal to 10cm, it is not necessary to measure in the area between the two. When the distance is greater than 10cm, measurement must be carried out (see Appendix A Figure A6). 7.3.4 When the sealed source is in the working position (source gate is open), the detection of radiation leakage outside the source container should be: a) For transmission instruments, the detection should be carried out under the condition of no object to be tested; b) For scattering instruments, the detection should be carried out under the condition of the object to be tested. The detection points should include: the positions shown in Appendix A: the positions with higher expected doses: the positions where personnel stay for a long time, etc. 7.3.5 For the detection at 5cm outside the boundary described in 4.7, the recorded reading value should be the average reading value over an area of 10cm2. For the detection at 100cm outside the boundary, the recorded reading value should be the average reading value over an area of 100cm. The distance between the detection point and the boundary should be measured by the center position of the detector of the protection dose measurement instrument. For instruments containing neutron sources, the detection 5 cm outside the boundary mentioned in 4.7 can be approximated by placing the probe of the neutron protection dose instrument close to the boundary position.
Appendix A
(Normative Appendix)
Schematic diagram of dose equivalent rate measurement area around source container A1 Schematic diagram of dose equivalent rate measurement area around source container of detection instrument Source component
Unit: cm
Figure A1 Schematic diagram of dose equivalent rate measurement area around source container of density meter Unit: cm
One meter at the best distance from the negative measuring head
-1.3cm thick copper screen, its width and height dimensions must be at least 5cm larger than the size of the radiation beam machine surface 100
Schematic diagram of dose equivalent rate measurement area around source container of level meter Figure A3
Chain simple chess batch material
Unit.cm
Thank product head
Schematic diagram of dose equivalent rate measurement area around β, T backscatter measuring instrument Unit cm
Measurement head
Figure A4 Schematic diagram of the dose equivalent rate measurement area around the surface backscatter measuring instrument 100
Measuring disk head
0.6cm original steel plate
Standard cancer scatterer, its size must be at least 5cm larger than the cross-section of the useful beam
2cm original polyethylene
Figure A5 Schematic diagram of the dose equivalent rate measurement area around the backscatter neutron measuring instrument A2 When the distance between the probe of the transmission detection instrument and the adjacent surface of the source container is less than, equal to or greater than 10cm, the equidistant contour line diagram of the dose equivalent rate measurement area around the source container when the source gate is "open" or "closed" is shown in Figure A6. 100
Source component
Source gate closed
Source component
Source in "open position"
Figure A6 Schematic diagram of equidistant contour lines4d test
Note: "√" in the table means that inspection is required, and "×" means that inspection is not required. 7.3 Instruments and methods for measuring leakage radiation
Visual inspection
Cyclic operation 10
7.3.1 The measuring instrument shall be suitable for the radiation type, energy and radiation level of the radiation to be measured. Visual inspection
7.3.2 During the type test, the activity of the sealed source in the source container shall be the rated activity value. When the activity of the sealed source is lower than the rated activity, the test result shall be multiplied by the coefficient K. K
Rated activity of sealed source
Activity of sealed source during inspection
7:3:3 When the sealed source is in the storage position (source gate closed), the source container leakage radiation detection points are as follows a) Take the sealed source as the coordinate origin, the useful beam center axis direction as the Z axis, and select any mutually perpendicular X and Y axes in the plane perpendicular to the Z axis. In the positive and negative directions of the X, Y, and Z axes, the detection is carried out at positions 5cm and 100cm away from the surface of the source container.
b) For transmission instruments where the source container and the detector are located on both sides of the object to be tested, when the distance between the adjacent surfaces of the source container and the detector on the useful beam axis is less than or equal to 10cm, it is not necessary to measure in the area between the two. When the distance is greater than 10cm, measurement must be carried out (see Appendix A Figure A6). 7.3.4 When the sealed source is in the working position (source gate is open), the detection of radiation leakage outside the source container should be: a) For transmission instruments, the detection should be carried out under the condition of no object to be tested; b) For scattering instruments, the detection should be carried out under the condition of the object to be tested. The detection points should include: the positions shown in Appendix A: the positions with higher expected doses: the positions where personnel stay for a long time, etc. 7.3.5 For the detection at 5cm outside the boundary described in 4.7, the recorded reading value should be the average reading value over an area of 10cm2. For the detection at 100cm outside the boundary, the recorded reading value should be the average reading value over an area of 100cm. The distance between the detection point and the boundary should be measured by the center position of the detector of the protection dose measurement instrument. For instruments containing neutron sources, the detection 5 cm outside the boundary mentioned in 4.7 can be approximated by placing the probe of the neutron protection dose instrument close to the boundary position.
Appendix A
(Normative Appendix)
Schematic diagram of dose equivalent rate measurement area around source container A1 Schematic diagram of dose equivalent rate measurement area around source container of detection instrument Source component
Unit: cm
Figure A1 Schematic diagram of dose equivalent rate measurement area around source container of density meter Unit: cm
One meter at the best distance from the negative measuring head
-1.3cm thick copper screen, its width and height dimensions must be at least 5cm larger than the size of the radiation beam machine surface 100
Schematic diagram of dose equivalent rate measurement area around source container of level meter Figure A3
Chain simple chess batch material
Unit.cm
Thank product head
Schematic diagram of dose equivalent rate measurement area around β, T backscatter measuring instrument Unit cm
Measurement head
Figure A4 Schematic diagram of the dose equivalent rate measurement area around the surface backscatter measuring instrument 100
Measuring disk head
0.6cm original steel plate
Standard cancer scatterer, its size must be at least 5cm larger than the cross-section of the useful beam
2cm original polyethylene
Figure A5 Schematic diagram of the dose equivalent rate measurement area around the backscatter neutron measuring instrument A2 When the distance between the probe of the transmission detection instrument and the adjacent surface of the source container is less than, equal to or greater than 10cm, the equidistant contour line diagram of the dose equivalent rate measurement area around the source container when the source gate is "open" or "closed" is shown in Figure A6. 100
Source component
Source gate closed
Source component
Source in "open position"
Figure A6 Schematic diagram of equidistant contour lines
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