GBZ 141-2002 Specification for protection testing of gamma ray and electron beam irradiation devices
Some standard content:
ICS13.100
National Occupational Health Standard of the People's Republic of China GBZ141-2002
Specifications for radialogical protection testof y-rays and electron irradiation facilities2002-04-08Promulgated
Ministry of Health of the People's Republic of China
Implementation on 2002-06-01
1. Scope
Normative references
Classification of irradiation devices
Testing items, frequency and instruments
Testing methods and evaluation
Inspection of radiation safety facilities
7. Test records and reports
Appendix A (Informative Appendix)
Appendix B (Informative Appendix)
Schematic diagrams of various irradiation devices
Radioactive source leakage detection device
This standard is formulated in accordance with the "Law of the People's Republic of China on the Prevention and Control of Occupational Diseases". Chapters 4 to 7 of this standard are mandatory contents, and the rest are recommended contents. This standard is a radiation protection detection specification supporting GB102521996 "Radiation Protection Standard for Cobalt 60 Irradiation Devices", GB172791998 "Design Safety Criteria for Pool-Stored Source Type × Irradiation Devices", and GB175681998 "Design, Construction and Use Specifications for Y Irradiation Devices". This standard applies to various types of Y source irradiation devices and electron accelerator irradiation devices with energy less than or equal to 10MeV.
This standard specifies the classification of irradiation devices, the instruments, methods and evaluation of radiation protection detection of various types of irradiation devices, such as external exposure leakage radiation dose level, surface contamination of radioactive materials, radioactive contamination of storage well water and leakage of radioactive sources, and also specifies the detection methods of radiation safety facilities. Appendix A and Appendix B of this standard are informative appendices. This standard is proposed and managed by the Ministry of Health.
The drafting unit of this standard: Beijing Institute of Radiation Health Protection. The main drafters of this standard: Wang Shijin and Lou Yun. The Ministry of Health is responsible for the interpretation of this standard.
1 Scope
Protection detection specification for gamma-ray and electron beam irradiation devices
GBZ141-2002
This standard recommends the technical specifications for radiation protection detection items, frequencies, methods and evaluation for gamma-ray and electron beam irradiation devices.
This standard applies to gamma-ray and electron accelerator irradiation devices with energy less than or equal to 10MeV. 2 Normative references
The clauses in the following documents become the clauses of this standard through reference in this standard. For all referenced documents with dates, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, the parties who reach an agreement based on this standard are encouraged to study whether the latest versions of these documents are applicable. For all referenced documents without dates, the latest versions are applicable to this standard.
GB5750
GB16140
GB/T10252
GB17279
GB17568
3 Classification of irradiation devices
3.1 Gamma ray irradiation device
《Standard test method for drinking water》
《Gamma spectrum analysis method for radionuclides in water》《Radiation protection and safety standard for cobalt-60 irradiation device》《Design safety criteria for pool storage type gamma irradiation device》《Design, construction and use specification of gamma irradiation device》According to the storage and irradiation method of radioactive sources, it is divided into Class 1 self-shielded (comprehensive) dry storage source irradiation device (see Appendix A Figure 1). Class II fixed source room (wide field of view) dry storage source irradiation device (see Appendix A Figure 2) Class IIIII comprehensive wet storage source irradiation device (see Appendix A Figure 3). Class IV fixed source room (wide field of view) wet storage source irradiation device (see Appendix A Figure 4). 3.2 Electron beam irradiation device
According to the conditions in which personnel can approach the irradiation device, it is divided into: Class I: an integral shielding device equipped with an interlocking device. During operation, personnel cannot actually approach the radiation source components of this device (see Appendix A Figure 5).
Class II: an irradiation device installed in a shielded room (irradiation room). During operation, an access control system is used to prevent personnel from entering the irradiation room (see Appendix A Figure 6).
4 Inspection items, frequency and instruments
4.1 External irradiation leakage radiation level detection
4.1.1 Inspection content
Radiation air kerma rate detection includes the following contents (1) Leakage radiation detection of the transport container carrying the Y-ray source used in the irradiation device. (2) Inspection of the operation and workplace during the installation, transfer and decommissioning of the radioactive source of the Y-ray irradiation device. (3) Acceptance of radiation levels outside Class I and Class II gamma-ray irradiators and Class I electron beam irradiators and periodic inspection during use. Periodic inspection shall be carried out at least once a year.
(4) Acceptance of radiation levels outside the irradiation room of Class II and Class IV gamma-ray irradiators and Class II electron beam irradiators and periodic inspection during use. Periodic inspection shall be carried out at least once a year. 4.1.2 Detection instruments
(1) Detection instruments shall include dose instruments for environmental radiation level and protection level. The lowest digit readout value of the environmental level instrument shall be ≤1×102μGy/h. The highest digit readout value of the protection level instrument shall be ≥1×10\mGy/h. (2) The instrument measurement error shall be ≤30%.
4.2 Surface radioactive contamination detection
4.2.1 Detection content
(1) Surface radioactive contamination detection of radioactive source transportation and inverted containers. (2) Surface radioactive contamination detection of equipment, tools, ground and workers' clothes and body surfaces in the workplace. 4.2.2 Detection Instruments
Instruments for directly measuring the surface contamination of radioactive materials shall meet the following requirements: (1) The detection efficiency of the detector of the instrument for -60β radioactive particles incident from the 2-dimensional direction shall be ≥10%. (2) The minimum detectable limit of surface contamination of the instrument (three times the standard deviation of the instrument background) shall be ≤0.4Bg/cm (3) When the instrument is used to measure surface contamination wipe samples (referred to as swab samples), its minimum detectable limit shall be ≤40Bq. (4) The measurement error of the instrument shall be ≤30%.
4.3 Radioactive contamination detection of water in the source well of the wet source (Class I, II, and IV) drilling -60Y ray irradiation device 4.3.1 Detection Contents
Radioactive contamination detection of water in the source well shall be carried out in the following circumstances: (1) Before the water in the source well is discharged.
(2) Before and after the installation (additional installation, decommissioning) of radioactive sources in the irradiation device, and before and after the cleaning of the source well. When the specific radioactivity of cobalt-60 in the first water sample after the operation is significantly higher than that of the control sample of the storage well water before the operation and is greater than 1Bq/L, the test shall be conducted every 1-2 weeks until the specific radioactivity of the well water no longer increases. (3) During normal operation, the storage well water shall be tested no less than once every six months. When the specific radioactivity of cobalt-60 in the water sample is found to be significantly higher than the previous test result by 5
and greater than 1Bq/L, the test shall be conducted every 1-2 weeks until the specific radioactivity in the water no longer increases.
4.3.2 Detection Instruments
(1) Laboratory instruments used for detection of radioactive contamination in storage well water generally include: low background β-ray measuring instruments for total β-radioactivity measurement, chemical analysis equipment for cobalt-60 composition, and gamma-ray spectrometers and liquid scintillation measuring instruments. (2) Low background β-ray measuring instruments should meet the following requirements: detection efficiency of cobalt-60β particles incident from the 2π direction ≥ 10%; minimum detectable limit for water samples: total β specific radioactivity calibrated with KC1 powder source ≤ 0.1Bq/L. (3) When measured with a gamma spectrometer or liquid scintillation meter, the minimum detectable limit for cobalt-60 specific radioactivity in water samples should be ≤ 1Bq/L.
4.4 Radioactive source leakage detection of dry degraded source (Class I, IⅡ) gamma-ray irradiation device 4.4.1 Detection content
After the radioactive source is installed in the irradiation device or when the radioactive source is decommissioned, the area that is accessible to personnel and may be contaminated shall be indirectly inspected for radioactive source leakage by wiping method. During normal operation, this inspection shall be carried out at least once every six months. 4.4.2 Inspection Instruments
(1) The detection efficiency of the detector of the instrument for cobalt-60β particles incident from the 2-dimensional direction shall be ≥10%, (2) The minimum detectable limit of the instrument for swab samples shall be ≤2Bq. 4.5 Radioactive Source Leakage Detection of Wet Source Storage (Class II, IV) Cobalt-60 Y-ray Irradiation Device 4.5.1 Inspection Contents
Radioactive source leakage detection shall be carried out in the following cases: (1) Before the radioactive source is decommissioned.
(2) The cobalt-60 specific radioactivity of the water in the source well is greater than 10Bq/L. (3) After the radioactive source exceeds the shelf life, each time the irradiation device is fully repaired or a radioactive source is added 4.5.2 Detection Instruments
(1) In the source storage well of the irradiation device, use the device described in Appendix B (Suggested Appendix) of this standard to obtain the test water sample, and measure its radioactivity to preliminarily check the leakage of the radioactive source. The measuring equipment for the test water sample is the same as that in Article 4.3.2. (2) For the radioactive source that may have leaked after preliminary inspection, it shall be sent to the manufacturer of the radioactive source or a unit with "hot room" operation and radioactive source leakage inspection conditions for sealed source leakage inspection. 5 Detection Methods and Evaluation
5.1 External Exposure Leakage Radiation Level Detectionbzxz.net
5.1.1 General Principles
(1) For the determination of the air kerma rate 5 cm from the surface, the detection instrument shall be scanned on the surface of the entire object to be tested to record the measured value at the position with the highest dose. Then measure the air kerma rate at the corresponding position 1 m from the surface6
(2) For electron beam irradiation devices, the measurement shall be carried out under rated working conditions. For gamma-ray irradiation equipment, the test results under the actual source activity shall only be used for evaluation under the source condition. For the acceptance test of the irradiation equipment, the test results shall be multiplied by the ratio of the designed rated source activity to the actual source activity during the test. (3) For the test of air absorption dose rate ≤10cm from the surface, the average value shall be taken over an area of 10cm with a longitudinal axis dimension ≤4cm; for the test 30cm from the surface, the average value shall be taken over an area of 100cm with a longitudinal axis dimension ≤20cm. 5.1.2 Inspection of radioactive source transport containers
5.1.2.1 When shipping and receiving radioactive source containers, the following dose verification shall be carried out on the transport package: (1) Measure the air absorption dose rate at 5cm from the surface along the entire package surface. Corresponding to the higher dose point measured, measure the air absorption dose rate (μGy/h) at 1m from the package surface, and use its ratio to 10uμGy/h to represent the transport index (TI). (2) Detect the air kerma rate on the outer surface of different transport vehicles: Detect the air kerma rate at the seat of the personnel during road transport.
5.1.2.2 The test results shall comply with the control values listed in the following table. Dose control values for transporting radioactive source packages
Transportation arrangements
Road transport
Package surface
1m from the package surface
Package surface
Surface of transport vehicle
2m from the transport vehicle surface
Staff seat
Air kerma rate control value, mSv/h
In the above table, special arrangements refer to: transportation that cannot meet the requirements of normal transportation arrangements and is specially approved by the competent authorities. For example: during rail and road transportation, the package is firmly fixed on the transport vehicle, there are protective measures to prevent personnel from entering the transport vehicle, and there is no loading and unloading operation between the starting point and the end point of the transportation. 5.1.3 Radiation level detection outside of Class I and Class I ray and Class I electron beam irradiators Measure the air kerma rate 5 cm away from the surface along the entire surface of the irradiator, and pay special attention to the measurement of possible weak points such as the source port and sample inlet.
The measurement result should generally be no more than 2.5uGy/h. 5.1.4 Radiation level detection outside the irradiation room of Class I and Class V gamma ray irradiators and Class I electron beam irradiators 5.1.4.1 The measurement positions of the air kerma rate are as follows: (1) The surface of the source well when the gamma ray irradiator is in the source storage state. 7
(2) 30 cm away from the shielding walls and entrances and exits of the irradiation room. (3) For single-story irradiators, on any vertical line perpendicular to the shielding wall of the irradiation room through the center of the radiation source, from the outer surface of the screen wall to the area within 20 m of it that can be reached by personnel. (4) For a single-story irradiation device, when there is a high-rise building within 50m and the high-rise building is located in the solid angle area between the radiation source irradiation position and the roof of the irradiation device room, measurements shall be made on the roof of the irradiation device room and (or) the corresponding high-rise building. 5.1.4.2 Fixed detection points shall be selected for regular measurements during operation, which must include: the surface of the source water well, the entrances and exits of the irradiation room, the ventilation and pipeline outlets passing through the irradiation room, the shielding walls and shielding roof, the operating room and the rooms directly adjacent to the irradiation room.
5.1.4.3 The measurement results shall comply with Article 5 of GB17279. 5.1.4.4 When the results of regular fixed-point measurements are significantly higher than those of the previous measurements, excluding the factors of changes in radiation source items, more comprehensive measurements shall be carried out to find out the reasons.
5.1.5 Radiation level detection during installation and decommissioning of radioactive sources in gamma-ray irradiation devices 5.1.5.1 The gamma-ray air kerma rate should be measured in the following situations or locations: (1) When the source container transport bag and the outer layer of the source container are disassembled. (2) When the source transport container is connected to the working container and the radioactive source is transferred between containers. 3) When the lead plug is removed from the source transport container that has been moved into the rotten source and the radioactive source is removed, the surface of the water well should be tested. (4) When the source transport container and the tool for inverting the source are removed from the source storage well, the surface of the water well should be tested. 5.1.5.2 Evaluation
(1) According to the dose rate of the possible source-related operation time and operation position, the dose equivalent of the personnel exposed during the entire source-related operation is estimated, and the value should not exceed 5mSv.
(2) For the empty container and the radioactive source inversion tool that have been removed from the radioactive source, the surface of the water well should be kept at the original radiation level when they are removed from the source storage well.
5.2 Surface radioactive contamination detection of Y-ray irradiation device 5.2.1 Surface contamination detection of radioactive source transport container 1) Draw a 15cm×20cm area on the outer surface of the transport container and wipe the area with gauze slightly soaked in alcohol. After removing the outer layer of the transport container (if any), wipe the top cover and side surface of the container with another gauze in the same way.
(2) Lay the gauze swab so that its area is smaller than the detection area of the surface contamination measuring instrument, lay a colorless plastic film on it, and measure directly with the surface contamination measuring instrument. Alternatively, use the laboratory's low-background β-ray measuring instrument for measurement. (3) Estimate the radioactivity of the swab and the surface contamination specific activity NN of the container according to the following formula.
Q=1.1×104（NN）/n
Where: A is the radioactivity of the swab, Bq; Q is the surface contamination specific activity of the container, Bq/cm2; N is the counting rate of the swab (counts/min); N is the instrument background counting rate at the same measurement position (counts/min); n is the detection efficiency of the instrument's detector for cobalt-60β particles incident from the 2-dimensional direction (counts/2-dimensional particles). For instruments that measure by counting, the counting rate is the quotient of the cumulative counts divided by the counting measurement time (min). (4) Evaluation: The surface contamination specific activity of the container should be less than 4Bg/cm. (5) For transport containers of non-depleted materials, the surface contamination detection of empty containers after unloading the radioactive source can be directly measured on the container surface using a surface contamination meter. The surface contamination specific activity Q is calculated as follows. Q=(NN) / K
Where: K is the scale factor of the instrument, (counts/min)/(Bq/cm). 5.2.2 Other surface contamination tests
(1) When installing or decommissioning radioactive sources, the inverted tools involved in the source shall be tested for surface contamination. When obvious radioactive contamination is found during the test, the surface contamination test in Item 4.2.1(2) shall be carried out. (2) When the specific radioactivity of the water in the source well is greater than 10Bq/L, the surface contamination test in Item 4.2.1(2) shall be carried out. (3) Evaluation: Control in accordance with Articles 3.3.3 and 3.3.4 of GB-10252. 5.3 Radioactive contamination test of water in source wells
5.3.1 Sampling:
(1) Take water samples from the bottom of the source well. When the specific radioactivity of the well water is greater than 10Bq/L, water samples shall be taken from the upper, middle and lower parts of the well.
(2) The volume of the water sample is 1-3L.
5.3.2 Measurement
5.3.2.1 Total β measurement method
(1) Test in accordance with Article 39 of GB5750. The test result is calculated according to formula (4). 1.47×10-2W,W, (n,-no)
YVW.(ng-no)
wherein Cp——total β radioactivity specific activity of water sample, Bq/L; W-weight of potassium chloride used to prepare standard source, mg; W-total weight of solid matter obtained after concentrating water sample, mg; Wx
-weight of solid powder used to prepare sample source, mg: Y—chemical recovery rate, which can be taken as 100%:
V—volume of water sample to be tested, L:
-β counting rate of potassium chloride standard source, counts/min; nk
nx—β counting rate of sample source, counts/min: (4)
no background counting rate of measuring device, counts/min. (2) When the total β radioactivity measured is greater than 0.5Bg/L, it shall be detected according to the following method. Add an appropriate amount of cobalt-60 standard solution to CaS0.1 powder to prepare a solution with a specific activity of F (Bq/mg) (close to 1.47×10Bq/mg) of cobalt-60 powder standard source
According to the method in Article 39 of GB5750, the cobalt-60 powder standard source is used instead of the KC1 source for measurement, and the measurement result is calculated according to formula (5): FW.W(n,-no)
Ce=yVw(n.-no)
Wherein: Cc—the weight of the cobalt-60 powder standard source prepared in the water sample, Bq/L; Wc—the weight of the cobalt-60 powder standard source prepared, mg; ne—the β counting rate of the cobalt-60 powder standard source, counts/min; other symbols—same as formula (4).
5.3.2.2Y energy spectrum method
Detect the cobalt-60 specific radioactivity in water in accordance with GB/T16140 5.3.3 Evaluation
When the total β specific activity measured by KC1 is greater than 0.5Bq/L or the specific activity measured by cobalt-60 powder standard source is greater than 1Bq/L, there is suspected contamination by radioactive substances and follow-up detection should be strengthened. When the specific activity of well water is greater than 10Bq/L, it shall not be discharged directly, but must be reported to the relevant regulatory authorities and water purification measures must be taken. 5.4 Radioactive Source Leakage Test
5.4.1 Thousand-method Storage Source Irradiation Device
(1) Carry out a swab test in accordance with Item 4.4 of this standard, using the same method as Item 5.2.1. (2) When the radioactive activity of the swab sample calculated in accordance with formula (1) is greater than 20Bg, the radioactive source in the irradiation device is suspected of leaking. The radioactive source supplier and the relevant regulatory authorities shall be reported and closely followed up for detection or the radioactive source shall be removed from the irradiation device and sent to the source supplier for further inspection and processing. 5.4.2 Wet-method Storage Source Irradiation Device
5.4.2.1 Use the test device described in Appendix B (Reminder Appendix) of this standard to carry out the test in Item 4.5.1 of this standard. The specific operation steps are as follows:
(1) Connect the test device conduit, put it into the bottom of the source water well, load the source to be tested in order, and cover the top plug. (2) Place the upper conduit port connected to the upper water injection nozzle in the air, and use a vacuum pump to pump out the water in the test device from the lower conduit port connected to the lower water injection nozzle.
(3) Place the lower conduit port in the test liquid to be injected (such as steam tank water), use a vacuum pump to pump the test liquid into the test device from the upper conduit port, and let it soak for a certain period of time (such as 1 hour) when there are no air bubbles in the system. (4) Place the upper conduit port in the air, and use a vacuum pump to pump the test liquid in the test device into the sampling bottle from the lower conduit port. 10
(5) Measure the specific radioactivity of the source-immersed liquid sample (test sample) and the unimmersed control sample according to 5.3, and estimate the detected radioactivity according to the total amount of test samples in the test system. (6) When the total radioactivity of the test sample is greater than 20Bq, take out one-third of the source to be tested in the test device each time and repeat the above test. After several tests, the problematic radioactive source can be found. (7) If it is difficult to open the top plug due to negative pressure in the test device, connect the vacuum pump outlet to the catheter port, turn on the vacuum pump, stop the pump when bubbles are discharged from the top plug, open the plug, and clamp out the radioactive source. 5.4.2.2 Evaluation
(1) When the total radioactivity of the test sample is greater than 20Bq, the radioactive source is deemed to be a sealable unqualified source and should be tracked and tested separately or sent to the source manufacturer for inspection. (2) When the total radioactivity of the test sample is greater than 185Bq, it is determined that the radiation source has leaked. The irradiation business must be stopped immediately, the supplier of the source and the competent department must be notified, and the leaked source must be sent to the source manufacturer for inspection and treatment. 6 Radiation safety facility inspection
6.1 Inspection content
The radiation safety inspection of the irradiation device includes all radiation safety and interlocking systems set up in accordance with the requirements of GB10252, GB17279, GB17568 and other standards.
6.2 Inspection frequency
In accordance with the requirements of Article 9 of GB10252, the radiation safety and interlocking systems of the irradiation device shall be inspected on a daily, monthly and annual basis. 6.3 General principles of inspection
6.3.1 Standardized inspection
The inspection must be completed by qualified personnel, and radiation protection officers must participate in the inspection. Standardized inspection methods must be established in accordance with the instructions of the radiation safety and interlocking equipment manufacturer or design unit, and the inspection results must be recorded in a standardized manner. 6.3.2 Comprehensive inspection
All items that should be inspected must be inspected according to the regular inspection time. 6.3.3 Independent inspection
The radiation safety and interlocking system is set up according to the "redundancy" principle. During the safety inspection, each function must be inspected independently according to the "independence" principle so that other safety equipment does not affect its operation. 6.4 Inspection method
6.4.1 Direct observation
For the working status indicator lights, warning lights, warning bells, etc. outside the irradiation room, they can be visually inspected when the irradiation device is running. 6.4.2 Simulation inspection
For the safety equipment outside the irradiation room, the safety equipment in the irradiation room that is not related to the location of the radiation source (such as water level control), and the manually controllable devices, simulated inspections shall be carried out.
6.4.3: Inspection under slightly lifted source conditions
Lift the irradiation source slightly, so that it just leaves the storage position at the bottom of the storage well, and enter the irradiation room under the supervision of no less than two personnel holding radiation dosimeters, manually control the radiation safety control device, and simulate the inspection of source lowering control. This inspection must ensure that the control console only places the radiation source in the position just left the storage source, and always keeps in touch with the inspection personnel entering the irradiation room. This inspection is only used when other methods cannot be used for inspection, and there must be on-site guidance from radiation protection experts during the inspection. 6.4.4 Preset "emergency" state
Preset the safety equipment to the "emergency" state (that is, enter the safety protection working state), and lift the source to check its function. For example: hang a heavy object and pull down the emergency source lowering rope; attach an opaque paper to the detector of the photoelectric and infrared interlocking; place a heavy object on the interlocking pedal; press the emergency button with a convex object, etc., and then conduct the source lifting experiment. 6.4.5 Radiation dosimeter inspection
Place a trace radioactive source with a protective container near the detector of the fixed or patrol dose (alarm) instrument, so that the instrument exceeds its interlocking control or alarm threshold, and check the interlocking or alarm function of the instrument. 6.5 Evaluation
The functions of all radiation safety facilities should be inspected and effective. 7 Inspection records and reports
7.1 All inspections must have standardized records, including the inspection date: radiation source conditions during the inspection: sampling method; the model and product series serial number of the instrument used for the inspection: calculation method, inspection results, inspector, etc. 7.2 The instruments used for the inspection must be calibrated before the first use, after each overhaul, or before the calibration time limit specified by the competent authority. The measurement certificate number of the inspection instrument and the correction factor and conversion coefficient must be listed in the inspection record. 7.3 In addition to the above inspection record items, the inspection report should evaluate the inspection results, give clear conclusions and opinions, and explain the national standards on which the conclusions are based.1 test. The specific operation steps are as follows:
(1) Connect the test device conduit, put it into the bottom of the source water well, load the source to be tested in order, cover the top plug, (2) Place the upper conduit port connected to the upper water injection nozzle in the air, and use a vacuum pump to pump out the water in the test device from the lower conduit port connected to the lower water injection nozzle.
(3) Place the lower conduit port in the test liquid to be injected (such as steam tank water), use a vacuum pump to pump the test liquid into the test device from the upper conduit port, and let it soak for a certain period of time (such as 1 hour) when there are no air bubbles in the system. (4) Place the upper conduit port in the air, and use a vacuum pump to pump the test liquid in the test device into the sampling bottle from the lower conduit port. 10
(5) Measure the specific radioactivity of the source-immersed liquid sample (test sample) and the unimmersed control sample according to 5.3, and estimate the detected radioactivity according to the total amount of test samples in the test system. (6) When the total radioactivity of the test sample is greater than 20Bq, take out one-third of the source to be tested in the test device each time and repeat the above test. After several tests, the problematic radioactive source can be found. (7) If it is difficult to open the top plug due to negative pressure in the test device, connect the vacuum pump outlet to the catheter port, turn on the vacuum pump, stop the pump when bubbles are discharged from the top plug, open the plug, and clamp out the radioactive source. 5.4.2.2 Evaluation
(1) When the total radioactivity of the test sample is greater than 20Bq, the radioactive source is deemed to be a sealable unqualified source and should be tracked and tested separately or sent to the source manufacturer for inspection. (2) When the total radioactivity of the test sample is greater than 185Bq, it is determined that the radiation source has leaked. The irradiation business must be stopped immediately, the supplier of the source and the competent department must be notified, and the leaked source must be sent to the source manufacturer for inspection and treatment. 6 Radiation safety facility inspection
6.1 Inspection content
The radiation safety inspection of the irradiation device includes all radiation safety and interlocking systems set up in accordance with the requirements of GB10252, GB17279, GB17568 and other standards.
6.2 Inspection frequency
In accordance with the requirements of Article 9 of GB10252, the radiation safety and interlocking systems of the irradiation device shall be inspected on a daily, monthly and annual basis. 6.3 General principles of inspection
6.3.1 Standardized inspection
The inspection must be completed by qualified personnel, and radiation protection officers must participate in the inspection. Standardized inspection methods must be established in accordance with the instructions of the radiation safety and interlocking equipment manufacturer or design unit, and the inspection results must be recorded in a standardized manner. 6.3.2 Comprehensive inspection
All items that should be inspected must be inspected according to the regular inspection time. 6.3.3 Independent inspection
The radiation safety and interlocking system is set up according to the "redundancy" principle. During the safety inspection, each function must be inspected independently according to the "independence" principle so that other safety equipment does not affect its operation. 6.4 Inspection method
6.4.1 Direct observation
For the working status indicator lights, warning lights, warning bells, etc. outside the irradiation room, they can be visually inspected when the irradiation device is running. 6.4.2 Simulation inspection
For the safety equipment outside the irradiation room, the safety equipment in the irradiation room that is not related to the location of the radiation source (such as water level control), and the manually controllable devices, simulated inspections shall be carried out.
6.4.3: Inspection under slightly lifted source conditions
Lift the irradiation source slightly, so that it just leaves the storage position at the bottom of the storage well, and enter the irradiation room under the supervision of no less than two personnel holding radiation dosimeters, manually control the radiation safety control device, and simulate the inspection of source lowering control. This inspection must ensure that the control console only places the radiation source in the position just left the storage source, and always keeps in touch with the inspection personnel entering the irradiation room. This inspection is only used when other methods cannot be used for inspection, and there must be on-site guidance from radiation protection experts during the inspection. 6.4.4 Preset "emergency" state
Preset the safety equipment to the "emergency" state (that is, enter the safety protection working state), and lift the source to check its function. For example: hang a heavy object and pull down the emergency source lowering rope; attach an opaque paper to the detector of the photoelectric and infrared interlocking; place a heavy object on the interlocking pedal; press the emergency button with a convex object, etc., and then conduct the source lifting experiment. 6.4.5 Radiation dosimeter inspection
Place a trace radioactive source with a protective container near the detector of the fixed or patrol dose (alarm) instrument, so that the instrument exceeds its interlocking control or alarm threshold, and check the interlocking or alarm function of the instrument. 6.5 Evaluation
The functions of all radiation safety facilities should be inspected and effective. 7 Inspection records and reports
7.1 All inspections must have standardized records, including the inspection date: radiation source conditions during the inspection: sampling method; the model and product series serial number of the instrument used for the inspection: calculation method, inspection results, inspector, etc. 7.2 The instruments used for the inspection must be calibrated before the first use, after each overhaul, or before the calibration time limit specified by the competent authority. The measurement certificate number of the inspection instrument and the correction factor and conversion coefficient must be listed in the inspection record. 7.3 In addition to the above inspection record items, the inspection report should evaluate the inspection results, give clear conclusions and opinions, and explain the national standards on which the conclusions are based.1 test. The specific operation steps are as follows:
(1) Connect the test device conduit, put it into the bottom of the source water well, load the source to be tested in order, cover the top plug, (2) Place the upper conduit port connected to the upper water injection nozzle in the air, and use a vacuum pump to pump out the water in the test device from the lower conduit port connected to the lower water injection nozzle.
(3) Place the lower conduit port in the test liquid to be injected (such as steam tank water), use a vacuum pump to pump the test liquid into the test device from the upper conduit port, and let it soak for a certain period of time (such as 1 hour) when there are no air bubbles in the system. (4) Place the upper conduit port in the air, and use a vacuum pump to pump the test liquid in the test device into the sampling bottle from the lower conduit port. 10
(5) Measure the specific radioactivity of the source-immersed liquid sample (test sample) and the unimmersed control sample according to 5.3, and estimate the detected radioactivity according to the total amount of test samples in the test system. (6) When the total radioactivity of the test sample is greater than 20Bq, take out one-third of the source to be tested in the test device each time and repeat the above test. After several tests, the problematic radioactive source can be found. (7) If it is difficult to open the top plug due to negative pressure in the test device, connect the vacuum pump outlet to the catheter port, turn on the vacuum pump, stop the pump when bubbles are discharged from the top plug, open the plug, and clamp out the radioactive source. 5.4.2.2 Evaluation
(1) When the total radioactivity of the test sample is greater than 20Bq, the radioactive source is deemed to be a sealable unqualified source and should be tracked and tested separately or sent to the source manufacturer for inspection. (2) When the total radioactivity of the test sample is greater than 185Bq, it is determined that the radiation source has leaked. The irradiation business must be stopped immediately, the supplier of the source and the competent department must be notified, and the leaked source must be sent to the source manufacturer for inspection and treatment. 6 Radiation safety facility inspection
6.1 Inspection content
The radiation safety inspection of the irradiation device includes all radiation safety and interlocking systems set up in accordance with the requirements of GB10252, GB17279, GB17568 and other standards.
6.2 Inspection frequency
In accordance with the requirements of Article 9 of GB10252, the radiation safety and interlocking systems of the irradiation device shall be inspected on a daily, monthly and annual basis. 6.3 General principles of inspection
6.3.1 Standardized inspection
The inspection must be completed by qualified personnel, and radiation protection officers must participate in the inspection. Standardized inspection methods must be established in accordance with the instructions of the radiation safety and interlocking equipment manufacturer or design unit, and the inspection results must be recorded in a standardized manner. 6.3.2 Comprehensive inspection
All items that should be inspected must be inspected according to the regular inspection time. 6.3.3 Independent inspection
The radiation safety and interlocking system is set up according to the "redundancy" principle. During the safety inspection, each function must be inspected independently according to the "independence" principle so that other safety equipment does not affect its operation. 6.4 Inspection method
6.4.1 Direct observation
For the working status indicator lights, warning lights, warning bells, etc. outside the irradiation room, they can be visually inspected when the irradiation device is running. 6.4.2 Simulation inspection
For the safety equipment outside the irradiation room, the safety equipment in the irradiation room that is not related to the location of the radiation source (such as water level control), and the manually controllable devices, simulated inspections shall be carried out.
6.4.3: Inspection under slightly lifted source conditions
Lift the irradiation source slightly, so that it just leaves the storage position at the bottom of the storage well, and enter the irradiation room under the supervision of no less than two personnel holding radiation dosimeters, manually control the radiation safety control device, and simulate the inspection of source lowering control. This inspection must ensure that the control console only places the radiation source in the position just left the storage source, and always keeps in touch with the inspection personnel entering the irradiation room. This inspection is only used when other methods cannot be used for inspection, and there must be on-site guidance from radiation protection experts during the inspection. 6.4.4 Preset "emergency" state
Preset the safety equipment to the "emergency" state (that is, enter the safety protection working state), and lift the source to check its function. For example: hang a heavy object and pull down the emergency source lowering rope; attach an opaque paper to the detector of the photoelectric and infrared interlocking; place a heavy object on the interlocking pedal; press the emergency button with a convex object, etc., and then conduct the source lifting experiment. 6.4.5 Radiation dosimeter inspection
Place a trace radioactive source with a protective container near the detector of the fixed or patrol dose (alarm) instrument, so that the instrument exceeds its interlocking control or alarm threshold, and check the interlocking or alarm function of the instrument. 6.5 Evaluation
The functions of all radiation safety facilities should be inspected and effective. 7 Inspection records and reports
7.1 All inspections must have standardized records, including the inspection date: radiation source conditions during the inspection: sampling method; the model and product series serial number of the instrument used for the inspection: calculation method, inspection results, inspector, etc. 7.2 The instruments used for the inspection must be calibrated before the first use, after each overhaul, or before the calibration time limit specified by the competent authority. The measurement certificate number of the inspection instrument and the correction factor and conversion coefficient must be listed in the inspection record. 7.3 In addition to the above inspection record items, the inspection report should evaluate the inspection results, give clear conclusions and opinions, and explain the national standards on which the conclusions are based.5 Radiation dosimeter inspection
Place a trace radioactive source with a protective container near the detector of a fixed or patrol dosimeter (alarm) so that the meter exceeds its interlock control or alarm threshold, and check the interlock or alarm function of the meter. 6.5 Evaluation
The functions of all radiation safety facilities should be inspected to be effective. 7 Inspection records and reports
7.1 All inspections must have standardized records, including the inspection date: radiation source conditions during the inspection: sampling method; the model and product series serial number of the instrument used for the inspection: calculation method, inspection results, inspector, etc. 7.2 The instruments used for the inspection must be calibrated before the first use, after each overhaul, or before the calibration deadline specified by the competent authority. The measurement certificate number, correction factor and conversion coefficient of the inspection instrument must be listed in the inspection record. 7.3 In addition to the above inspection record items, the inspection report should evaluate the inspection results, give clear conclusions and opinions, and explain the national standards on which the conclusions are based.5 Radiation dosimeter inspection
Place a trace radioactive source with a protective container near the detector of a fixed or patrol dosimeter (alarm) so that the meter exceeds its interlock control or alarm threshold, and check the interlock or alarm function of the meter. 6.5 Evaluation
The functions of all radiation safety facilities should be inspected to be effective. 7 Inspection records and reports
7.1 All inspections must have standardized records, including the inspection date: radiation source conditions during the inspection: sampling method; the model and product series serial number of the instrument used for the inspection: calculation method, inspection results, inspector, etc. 7.2 The instruments used for the inspection must be calibrated before the first use, after each overhaul, or before the calibration deadline specified by the competent authority. The measurement certificate number, correction factor and conversion coefficient of the inspection instrument must be listed in the inspection record. 7.3 In addition to the above inspection record items, the inspection report should evaluate the inspection results, give clear conclusions and opinions, and explain the national standards on which the conclusions are based.
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