GB 17279-1998 Safety criteria for the design of pool-type γ-irradiation devices
Some standard content:
GB 17279--1998
This standard is a revision of EJ377 based on ANSI N4. 3-1o-1984 Safe Design and Use of Panoramic. Wet. Source Storage Gamma Irradiators (Category IV), combined with GB10252 and comprehensive experience feedback from current design and operation practices. It will replace EJ377 after publication. The "Safety Design Principles" in this standard are compiled with reference to IAEA Safety Series No. 107. The purpose of compiling this standard is to provide design safety criteria for pool storage type gamma irradiators to prevent accidents and ensure the safety of workers and the public.
Appendix A, Appendix B, Appendix C, Appendix D, Appendix E, and Appendix F of this standard are all informative appendices. This standard was proposed by China National Nuclear Corporation. Drafting unit of this standard: Second Research and Design Institute of Nuclear Industry. Main drafter of this standard: Xing Fuli.
1 Scope
National Standard of the People's Republic of China
Criteria for safe design of
wet source storage gamma irradiators This standard specifies the safety criteria for the design of wet source storage gamma irradiators. GB 17279--1998
This standard applies to the design of wet source storage gamma irradiators. The design of other types of irradiators may refer to it. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and the parties using this standard should explore the possibility of using the latest versions of the following standards. GB3095-82 Atmospheric Environmental Quality Standard
GB8703-88 Radiation Protection Regulations
GB10252--1997 Radiation Protection Regulations for Co Irradiators for Radiation Processing 3 Definitions
This standard adopts the following definitions.
3.1 Irradiation device
A facility equipped with a sealed source and its supporting equipment, used to irradiate articles or materials. 3.2 Irradiation room
An area in the irradiation device that is enclosed by a radiation shield and cannot be entered by personnel when the source is in use. 3.3 Water tank storage source irradiation device
An irradiation device that can effectively control personnel from excessive exposure to sealed sources. This irradiation device consists of a sealed source, a control system, a ventilation system, a water tank and an irradiation room. When not in use, the sealed source is stored in the water of the water tank and is completely shielded. When in use, it is exposed in the irradiation room. When the source is in use, the passage to the irradiation room is controlled by a safety interlock so that personnel cannot enter. 3.4 Accessible interface
An interface inside the irradiation device that can be directly reached by personnel without passing through the building (structure) shield or using tools. These interfaces are determined by the shielding design.
3.5 Sealed source
A source made of radioactive material sealed in a shell. The shell of the source is strong enough so that no radioactive material will be released under the specified design and use conditions.
3.6 Penetrating radiation
Radiation emitted from a sealed source on the outer surface of the shielding wall of the irradiation room and the water surface of the source storage pool. 3.7 High radiation area
Refers to an area where the radiation dose rate is greater than 1mSv/h. 3.8 Safe state (completely shielded state)
Approved by the National Technical Supervision Kitchen on March 20, 1998 and implemented on September 1, 1998
GB 17279—1998
Refers to the state in which the radiation source is under the predetermined safe storage conditions. 3.9 Safety interlock device
Important safety control system of irradiation device, in which the actions of related components are interrelated, and the actions of each component are controlled by pre-defined states and (or) conditions. As long as any state and (or) condition of any component does not meet the pre-defined requirements, it can prevent the radiation source of the irradiation device from being put into use from a safe state, or immediately restore the radiation source that has been put into use or is being put into use to a safe state, or prevent personnel from entering the irradiation room of the irradiation device to protect them from exposure. 3.10 Safety-related service operation
Refers to any service operation that may affect the radiation safety of the irradiation device, such as: installing the source, changing the source or re-changing the distribution of the source, bypassing any safety interlock components; shielding changes that may lead to increased radiation levels, etc. 3.11 Product transmission and positioning system
A transmission system that transports the irradiated objects in a predetermined position sequence to the vicinity of the source in use conditions for irradiation. 3.12 Fully unobstructed
refers to a design feature of hollow tools, pipes or control rods, which allows air to be quickly expelled from the cavity when these devices are inserted into water, while water simultaneously enters the submerged part. 4 General requirements
4.1 Safety factors
The design must consider the following three factors and take corresponding safety measures: a) Radiation exposure:
b) Ozone, nitrogen oxides and other harmful gases produced by radiation; c) Disasters such as fire and ground capsules.
4.2 Radiation safety objectives
The design should provide reasonable guarantees for the realization of the following radiation safety objectives: a) During normal operation, maintenance and decommissioning, ensure that the radiation exposure to workers and the public is kept at the lowest level that can be reasonably achieved after taking into account economic and social factors; b) During normal operation, maintenance and decommissioning, ensure that the radiation exposure to workers and the public is kept below the relevant dose limits prescribed by the State;
c) Ensure that after taking into account economic and social factors, the probability of serious accidents and the size of the radiation doses caused by them are kept at an acceptable level.
4.3 Safety Design Principles
The design should comply with the following safety principles:
a) Defense in depth, i.e., multiple levels of defense measures should be provided so that if any level of defense measures fails, accidents can still be prevented or their consequences can be mitigated;
b) Redundancy (multiplicity), i.e., for components or systems that perform important safety functions, more items than the minimum required items should be provided so that the safety function is not lost when any one of the items fails or does not work; c) Diversity, i.e., for various redundant components or systems, items attributable to different working principles, different operating conditions or different manufacturers should be used to prevent common cause failures; d) Independence, i.e., independence should be maintained between redundant components or systems, between system equipment and the effects of initiating events, between items important to safety and items not important to safety, etc. by adopting functional isolation or physical separation. 4.4 Safety Analysis
A safety analysis should be conducted on the design of the irradiation device to confirm that the completed design and related operating procedures can achieve the purpose of preventing accidents and mitigating the consequences of accidents. The safety analysis report should describe and analyze the functions and reliability of the structures, systems and components of the irradiation device, describe the operating organizational structure and its functions and the management procedures adopted, and analyze in detail possible incidents or accidents. Safety 464
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The accident or failure analysis in the analysis report shall at least include: a) Failure of the entrance control of the irradiation room;
b) System or component failure and malfunction;
c) Failure of the movement control of the radiation source;
d) The integrity of the system or component, such as the shielding, source sealing and the integrity of the pool, is damaged; e) Power failure, partial or even complete loss of external power; f) The consequences of external events, such as storms, floods, earthquakes or explosions; g) Human error;
h) Failure of anti-intrusion measures;
i) Unsafe practices caused by the destruction of management procedures. 5 Radiation zoning and its shielding design limits
5.1 Zoning
The workplace inside the irradiation device should be zoned according to the provisions of GB10252. 5.2 Shielding design limits
For the supervised area, the average dose rate generated by penetrating radiation at 30cm from the accessible interface of the shield should not exceed 2.5×10-\mSv/h. The average dose rate on any 100cm2 surface area of the shield is allowed to reach 2×10-2mSv/h, but the average dose rate on the 1m area 1m away from the accessible interface of the shield and parallel to the interface shall not exceed 2.5X10-\mSv/h. For the unrestricted area, the shielding design must ensure that the annual dose to the public in and near the area does not exceed 0.1mSv. The dose rate control value adopted in the shielding design shall be further optimized and analyzed on the basis of meeting the above provisions. 6 Design requirements for safety systems and components closely related to operational safety. The diagram of the safety systems and components of a typical water pool storage source irradiation device is shown in Appendix A (suggestive appendix). 6.1 Orderly interlock control system for the operation process An orderly interlock control system must be set up for the entry and exit of personnel, the locking of the irradiation room, and the lifting and lowering of the radiation source. This control system must be designed so that any operation that preempts, disrupts or abandons the control procedure will automatically interrupt the attempted operation and put the source in or restore it to a fully shielded state. Examples of orderly control of operations are as follows: a) Orderly control of personnel entering the irradiation room: 1) Ensure that the access control system of the irradiation room can only be powered on the console with a single multi-purpose key (hereinafter referred to as the single multi-purpose key, see 6.2); 2) Check and confirm that the functions of the monitors (including probes and electronic equipment) in the irradiation room meet the requirements, and confirm that the radiation level in the irradiation room is not greater than the acceptable value;
3) Open the access door with a single multi-purpose key; 4) Use a portable radiation survey meter to continuously monitor the radiation level when entering the irradiation room. b) Locking sequence of the irradiation room:
1) Use a single multi-purpose key to start the safety delay in the irradiation room; 2) Close and lock the access door of the irradiation room.
c) Operation of the radiation source:
1) Use a single multi-purpose key on the console to start the radiation source hoist within the set delay time; 2) The radiation source is put into operation, but it is impossible to remove the single multi-purpose key without interrupting the operation of the irradiation device. 6.2 Single multi-purpose key
The interlock control system of the irradiation device must be designed so that under normal circumstances, the irradiation device can only be operated with a single multi-purpose key. The function of this key is to operate the control console to open the passage to the irradiation room and start the safety delay. 465
GB17279—1998
This single multi-purpose key should be tied to the portable radiation survey meter or portable sound alarm with a chain or cable long enough to operate all switches. Only authorized persons can use this key. 6.3 Portable radiation survey meter and calibration source
Operators entering the irradiation room must carry a portable radiation survey meter or portable sound alarm connected to a single multi-purpose key.
The design must provide a calibration source for operators to verify that the radiation survey meter and sound alarm are in normal working condition before entering the irradiation room each time.
6.4 Radiation monitor with alarm function
When the source is indicated to be in full shielding state, there must be a monitor to detect the radiation level in the irradiation room. This monitor must be integrated with the interlocking device of the personnel access door to prevent personnel from entering the irradiation room in the following situations: a) The radiation level detected by the monitor exceeds the specified value, or b) The blue detector itself is in an abnormal working state, or c) The blue detector is in the off state.
When the source is indicated to be in full shielding state, if the radiation level exceeds the specified value, the monitor should send out visual and audible signals. Before the operator enters the irradiation room, the monitor (including the probe and electronic equipment) must be inspected to ensure that it meets the specified functional requirements and is in normal condition.
6.5 Warning signs
The personnel access door leading to the irradiation room must be equipped with a clearly visible sign with radiation symbols and words, such as "Caution for radioactive materials" or "Dangerous radioactive materials". This sign should also comply with the requirements of GB8703. 6.6 The interlocking device of the personnel access door of the irradiation room must be designed to provide measures to reliably lock the personnel access door to the irradiation room before the source is removed from the fully shielded state. The access door interlocking device must be integrated with the main control system to ensure that the source automatically enters the fully shielded state in the event of a violation of the interlocking procedure or the use rules of the access door.
When the source is not in When an attempt is made to open the passage door by abnormal start-up or violation of the interlock in the fully shielded state, a visual and audible signal should be issued to alert the personnel trying to enter the irradiation room to the danger. 6.7 Safety delay device with alarm
The irradiation room must be equipped with a safety delay device operated by a single multi-purpose key. This delay device can automatically send out visual and audible alarm signals to warn the personnel in the irradiation room that the source lifting procedure has begun; and provide sufficient time for the personnel staying in the irradiation room to evacuate the area or activate an easily identifiable emergency stop device to terminate the source lifting procedure. The safety delay device must be integrated with the main control system to Ensure that the source cannot be lifted before the source lifting procedure is completed and the control console indicates that the source can be lifted safely.
6.8 Emergency exit capacity requirements
The design must provide means (see 6.9 and 6.10) to ensure that operators can evacuate the irradiation room at any time. 6.9 Emergency stop device in the irradiation room
Means must be provided in the irradiation room to prevent, quickly interrupt or terminate the operation of the irradiator at any time and return the source to a fully shielded state. This emergency stop device must be installed in an easily accessible position in the irradiation room and marked with obvious signs. 6.10 Emergency stop device on the control console||tt ||An emergency stop device must be provided on the control console to prevent, quickly interrupt or terminate the operation of the irradiator at any time and return the source to a fully shielded state. This emergency stop device must be clearly marked and, together with other normal stop means provided on the control console, shut down the irradiator.
6.11 Product inlet and outlet interlocking device
Physical means must be provided at the product inlet and outlet to prevent personnel from inadvertently or accidentally entering high radiation areas. Audio and visual signals must be provided to indicate whether the inlet and outlet product control mechanism has failed. 166
6.12 Product outlet monitor
GB 172791998
A fixed radiation monitor with an audible alarm must be installed to detect the radiation level at the product exit. This monitor should be interlocked with the irradiation device console. When the radiation level at the exit exceeds the predetermined value, the conveyor carrying the product from the irradiation room to the exit will be stopped and the source will automatically enter the full shielding state. 6.13 Interlocking of source status and source lifting system Interlocking measures must be taken to ensure that the source automatically enters the full shielding state when the source lifting device malfunctions. The source lifting system must also be equipped with equipment that can reliably indicate on the console that the source is in the full shielding state. 6.14 Indicator
6.14.1 Source status indication
When the source is neither in the full shielding state nor in the working state, an intermittent alarm sound must be audible in the irradiation room and at each channel entrance. A source status indicator must be installed on the control console to indicate: a) the source is in full shielding state;
b) the source is in working state;
c) the source is neither in full shielding nor in working state. If the source is indicated as not in full shielding state, the corresponding indication of the source status indicator must be visible at the personnel entrance and exit and the product entrance and exit.
6.14.2 Sound signal
The sound signal designed for each system of the irradiation device must be clear and loud enough to immediately attract the attention of the staff. 6.15 Removable irradiation room shielding plug
The removable shielding plug should be interlocked with the main control console so that when a removable shielding plug is pulled out, the operation of the irradiation device can be prevented or inhibited, so that the source is in full shielding state.
6.16 Source rack
Means for positioning the sealed source and keeping it in the predetermined position must be provided. When the irradiation device is in normal use, if the source frame that positions and maintains the source position fails, the source shall not be moved to a position that may cause danger to the human body. 6.17 Source protection
Adequate mechanical protection must be provided for the radiation source. For example, protective sleeves, guide rods, or ground indicators can be used in the product positioning system to prevent the source surface from colliding with the surface of the product box or the carrier. The product positioning system cannot directly or indirectly exert force on the radiation source.
6.18 Product positioning system
The product positioning system must be equipped with a detection system. When an abnormal working condition of the positioning system is detected, the source must automatically enter a full shielding state and terminate the operation of the irradiation device.
6.19 Pool protection
A physical barrier must be set around the open pool (which can be removed during maintenance or auxiliary operations) to prevent relevant personnel from accidentally falling into the pool.
6.20 Fire prevention
6.20.1 Precautions must be taken in the design to protect the integrity of the source in the event of a fire and to automatically put the source into a fully shielded state. 6.20.2 Heat and smoke sensors with visual and audible alarms must be installed in the irradiation room to detect fire. As long as one of the sensors alarms, the source must automatically enter a fully shielded state, and the product transmission and positioning and ventilation systems must stop working. 6.20.3 A fire extinguishing system must be installed in the irradiation room. If a water sprinkler fire extinguishing system is used, appropriate measures should be taken to prevent water from overflowing from the room of the sprinkler system. Www.bzxZ.net
In addition to the sprinkler system, if other fire extinguishing systems are used, chemical substances and corrosive substances that have adverse effects on the sealed source should be avoided.
6.21 Control of harmful gases
GB17279-1998
Measures must be taken in the design to ensure that the concentration of ozone and other harmful gases produced by irradiation decomposition does not exceed the limit value to protect the safety of the staff.
6.21.1 Measures must be taken (such as using a ventilation system to maintain a negative pressure in the irradiation room, etc.) to ensure that the ozone concentration in the personnel working area is not greater than 0.16mg/m2 (0.1ppm). For specific calculations, see Appendix B (Suggested Appendix). When a forced ventilation system is used, the ventilation volume must be continuously monitored. When the ventilation system fails, the source must automatically enter a fully shielded state and the product irradiation system automatically stops working. Relevant personnel must be prevented from entering areas where the ozone concentration exceeds the time-weighted average permissible concentration or the short-time concentration limit. Ozone is easy to decompose, so a large-volume continuous ventilation system should be set up so that workers can enter the irradiation room a few minutes after the source enters the full shielding state, while greatly reducing its oxidative effects on the components and devices in the irradiation room. The personnel access door must be opened only when the ozone concentration in the irradiation room reaches an acceptable level (achieved by the personnel access door delay interlock device).
6.21.2 The concentration of nitrogen oxides and other harmful gases must be lower than the limit specified in GB3095. 6.22 Cut-off of the source lifting device during service operations The power source (electricity, wind power, water power) used for lifting the source must be equipped with a cut-off device to ensure that there is no danger caused by accidental lifting of the source during service operations.
Measures must also be taken to ensure that the device used for service operations is in a partitioned position, or that the source lifting device is in a non-operating state. 6.23 Power failure
6.23.1 If a long-term (more than 10s) power failure occurs, measures must be taken to automatically put the source into full shielding state and stop the irradiator automatically.
6.23.2 If a short-term (no more than 10s) power failure occurs, it is acceptable to take measures to avoid unnecessary shutdown of the irradiator.
6.24 Other non-electrical power failures
Effective measures must be provided to automatically put the source into full shielding state and stop the irradiator when other non-electrical power (such as wind or water) failures occur.
6.25 Geological and seismic considerations
6.25.1 The geological characteristics of the site that may adversely affect the shielding integrity of the irradiator should be evaluated, such as: a) geophysical characteristics of the surface and underground; b) collapse or uplift;
c) geotechnical stability, etc.
6.25.2 The design of the irradiation device built in the area must be able to maintain the integrity of the shielding at the design basis earth (DBE), and the irradiation device should be equipped with an earthquake detector. Once the response of the detector exceeds the predetermined value, the source will automatically enter the full shielding state. Note
1 In this standard, the ground area refers to the area where the probability that the horizontal acceleration of the bedrock does not exceed 30% of the gravity acceleration (0.3g) within 50 years is 90%, that is, the probability that the horizontal acceleration is greater than 0.3g within 50 years is 10%. Design basis earthquake (DBE) refers to the maximum ground motion that can be reasonably expected to be experienced once due to an earthquake during the operating life of the irradiation station. If the ground motion of the ground exceeds the above ground motion, the irradiation station needs to be re-inspected to prove its ability to resume operation. 6.26 Security considerations for irradiation devices
Appropriate security measures should be taken in the design. In addition, all equipment installed at a long distance that may endanger personnel safety if misused (such as source hoists or their components installed on the roof of the radiation room) must be installed in an interlocked supervision area. 7 Radiation shielding and barrier integrity design requirements 7.1 Shielding design requirements for source storage pools
7.1.1 The bottom plate and pool wall of the pool should be made of concrete as structural material and shielding. The thickness of the bottom plate and pool wall should meet the shielding requirements, and the structural strength should ensure that there will be no cracks or penetration under the load of the design basis earthquake and the transport container carrying the source. 7.1.2 An automatic water level control system that can automatically replenish water should be designed to maintain the water level of the pool. The thickness of the water layer in the pool shall not be lower than the predetermined minimum thickness value under any circumstances. The calculation method of the thickness of the water layer of the pool shielding water layer is shown in Appendix C (Suggested Appendix). 7.1.3 The hollow pipes in the source storage pool must be completely unobstructed to facilitate its filling with water. 7.1.4 The specific gravity of the tools or objects introduced into the pool should be equal to or greater than 1; if they are hollow, they must be completely unobstructed. 7.2 Shielding design requirements for irradiation rooms
7.2.1 The shielding wall of the irradiation room should be constructed with concrete. The thickness of the concrete shielding wall can be determined using the estimation method provided in Appendix D (suggested Appendix). When constructed with other materials (such as soil residue, steel plate, etc.), its thickness should meet the shielding requirements, and its structural strength should meet the design benchmark earthquake conditions without cracking or disintegration. In order to prevent the thinning of the shielding thickness caused by the penetration of the pipeline, appropriate remedial measures should be adopted, such as making the pipeline bend, trapezoidal penetration or adding local shielding.
7.2.2 The design of the irradiation room roof should consider whether the roof is used, and must also consider the influence of the sky reflection of the rays. If necessary, detailed design calculations should be carried out to ensure safety. The protection design method of the irradiation room roof is shown in Appendix E (suggested Appendix). 7.3 Design requirements for the entrance and exit passages of the irradiation room
The entrance and exit passages of the irradiation room must be designed as a maze. The design method of the maze is shown in Appendix F (suggested Appendix). In addition to ensuring sufficient radiation reduction, the design of the passage door should also meet fire protection requirements. 8 Design requirements for source storage pools, components in the pool and water level control systems in the pool 8.1 Pool integrity requirements
8.1.1 The design of the pool should take into account various influencing factors. When designing according to the requirements of Article 7.1, in addition to avoiding water leakage, the effects of source containers and lifting equipment on the pool during source transportation should also be considered. 8.1.2 There should be no penetrations at the bottom of the pool, such as pipes, pipe plugs, etc. There should be no penetrations on the pool wall below the horizontal line 30 cm below the designed normal water level.
8.1.3 The materials of various permanent components in the source storage pool should be corrosion-resistant and should not have an adverse effect on the service life of the source. If necessary, measures such as coating should be taken.
8.2 Water level control system
When the water level drops, the water level control system should be able to automatically replenish water, and a water replenishment indicator should be set. When the water level drops to a horizontal line 30cm below the designed normal water level, the water level control system should be able to send out visual and audio alarm signals. 8.3 Requirements for maintaining pool water quality
Appropriate measures should be taken in the design to maintain the quality of pool water. The measures to be taken may include: a) Setting up an appropriate pool water purification system. When the conductivity of the pool water exceeds 1000S/m, purify the water to reduce corrosion to the source;
b) Prevent pollutants such as deionizer regenerators, detergents, corrosive fire extinguishing materials, spilled debris, etc. from falling into the water; c) Prevent pool water from entering the municipal water supply system; d) Before backwashing or regenerating the filter or resin bed of the water purification system, conduct radioactive contamination monitoring. If the contamination exceeds the predetermined value, backwashing or regeneration operations shall not be performed. At the same time, it should be ensured that the storage, treatment or disposal of waste filters and waste resin beds and the discharge of flushing liquid meet environmental protection requirements.
8.4 Pool water cooling requirements
Necessary pool water cooling measures should be provided to prevent the increase of water evaporation and air humidity caused by source heat release, which will have an adverse effect on the product and product positioning system. At the same time, the reduction of pool water evaporation loss is also conducive to maintaining the conductivity of pool water within 1000μS/m for a long time.
8.5 Pool pipeline design requirements
When designing the pipelines of the water level and water quality maintenance system, appropriate anti-siphon measures should be taken to prevent the water level from dropping below the horizontal line 30cm below the designed normal water level due to siphoning.
8.6 Pool cleaning requirements
GB 172791998
Appropriate means, such as a suction system with appropriate filters, should be provided to promptly remove dirt accumulated at the bottom of the pool. 9 Control Labeling
9.1 Control Panel
The control panel should be easily identifiable and each control button should be clearly labeled according to its function. 9.2 Status indication color
When light color is used as an indication of the control status, the color identification should be used according to Table 1. Table 1 Status color identification
Emergency (stop button or light)
Danger warning
Key information (the source is in working state or abnormal state) Attention (non-emergency accident but requires attention to a certain operation process) Normal (the source is in a safe state)
Information transmission
10 Other requirements
International universal trefoil symbol or red
Yellow or orange
10.1 In order to prevent pollution, the design should propose methods for pollution monitoring and means of decontamination. The sampling method can be used for water media, and the wiping method can be used for the surface of the equipment.
10.2 The design must provide instruments and equipment for radiation field inspection, pollution monitoring and water quality control inspection, and clearly specify the sensitivity and range of various instruments according to actual needs. 10.3 The design should provide adequate means and convenient operating sites for the integrity verification of radiation sources and the installation, replacement or maintenance of radiation sources. 10.4 The design should provide appropriate storage locations and testing means for used spent sources or leaking sources. 10.5 The design should provide guiding documents for the preparation of operating procedures, maintenance rules and safety inspections for safe operation, accident handling and safety inspections.
10.6 In terms of design, means for classified collection and reasonable storage locations should be provided for waste generated by irradiation stations. 11 Design quality assurance requirements
11.1 Quality assurance outline
The design unit should formulate and implement an appropriate design quality assurance outline. 11.2 Design control measures
Design control measures must be strictly implemented for radiation protection, human factors, fire prevention, ground and accident analysis, and accessible interfaces for maintenance and repair.
11.3 Design Control
Design control must ensure that design requirements are correctly reflected in technical specifications and drawings, and that appropriate quality standards are specified in design documents.
11.4 Design Changes
When design documents are changed, they must be approved by the same unit that approved the documents or by a specially designated unit. The revision of documents should be notified to all relevant units and individuals as soon as possible to prevent the use of outdated or inappropriate documents. 170
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Appendix A
(Suggestive Appendix)
Illustration of safety characteristics of irradiation device
1…-Water cooler; 2--Irradiation room ventilation system; 3--Irradiation room monitoring probe; 4--Safety delay alarm; 5--Emergency stop device, 6--Heat and smoke sensor, 7--Normal water level control; 8--Abnormal water level control; 9--Source elevator; 10--"Source down" switch; 11--Roof plug interlock switch; 12--Pool protection, 13--Irradiation room concrete shield; 14--"Source up" switch, 15--Source pool, 16--Safety delay key switch; 17--Exhaust inlet; 18--Personnel and product entry/exit maze; 19--Radiation warning light; 20--"Source moving" light; 21--Product Product entry/exit door? 22—Product entry/exit channel; 23 Product exit monitoring, 24—Source elevator power off 125—Source position check: 26—Interlocked personnel entrance door: 27--Irradiation room monitor with signal; 28--Seismic detector; 29-Single multi-purpose key connected to portable measuring instrument; 30-Control console 31-Water regulator Figure A1 Illustration of safety characteristics of irradiation device
Appendix B
(Suggested appendix)
Calculation of ozone exclusion in irradiation transformer
The following formula is recommended to calculate the ozone generation rate in the entire irradiation room n=5.206×1092HV (ozone molecules/h). (B1)
Where: V,-—The volume of the micro-volume element in the irradiation room, m; H;-dose equivalent rate, Sv/h.
When the irradiation device has been running for a long time, that is, the running time is much longer than the effective ventilation time, the indoor ozone concentration reaches the saturation concentration C.
Wherein; C,
GB 17279-1998
-Indoor ozone saturation concentration, mg/m; T. Effective ventilation time, min;
Actual ventilation time, min;
Ozone decomposition time, about 50min.
(B2)
(B3)
When the C. value is greater than the concentration limit of the workplace, personnel are not allowed to enter. At this time, either increase the ventilation frequency or wait for a period of time ta under the original ventilation frequency. ta is calculated by the following formula: ta = Tln
Wherein, the ozone concentration limit C,=0.16mg/m. Appendix C
(Suggested Appendix)
Schematic diagram for calculating the shielding thickness of the reservoir water
Single drill rod
Drill rod assembly
Calculation point 2
Schematic diagram for calculating the water layer thickness of the reservoir water
Calculation point 1
Concrete
Figure C2 Schematic diagram for calculating the shielding of the auxiliary pool
Protective water layer thickness
(B4)
Let the dose equivalent rate reduction factor K be
Where: Ｈ-
GB17279—1998
Appendix D
(Suggested Appendix)
Point source shielding calculation
When the irradiation room has a protective wall, the dose equivalent rate of a certain point outside the room at a distance R from the source, Sv/h; when the irradiation room has no protective wall, the dose equivalent rate of a certain point outside the room at a distance R from the source, Sv/h. The thickness of the protective wall can be determined using the relationship
.
Where: S. —Point source intensity, S-\;
n——Conversion coefficient between ray flux density and air absorption dose rate; Q——Quality factor, for ray Q1.
（D2）
Assuming that the radiation from the 6°Co radiation source is monoenergetic and its energy is equal to 1.25MeV, the flux density equivalent to 2.5×10-2mSv/h is 1300/cm2·s.
Table A1 gives the corresponding relationship between the isotropic point source radiation attenuation factor K and the concrete protective wall thickness value t. As long as the K value is calculated by formula (A1), the required concrete shielding layer thickness value can be found. When other materials such as lead, cast iron, water, etc. are used as protective walls, the Kt corresponding relationship numerical table or curve can be found in the relevant data. Table D1
2×105×1001
1×10%2×105×10
1×10%2×1025×1021×10%
1×102×1055×10%1×102×10%5×10%1×102×1075×107104.1112.2118.3124.3
132.3138.2144.2
152.1158.0163.9
Appendix E
(Suggested Appendix)
Calculation of the protective thickness of the irradiation room roof
The following method is recommended for calculating the thickness of the irradiation room roof. The sky backscatter radiation dose equivalent rate at point P in the figure is estimated according to the following empirical formula:4 Design Changes
When design documents are changed, they must be approved by the same unit that approved the documents or by a specially designated unit. The revision of the documents should be notified to all relevant units and individuals as soon as possible to prevent the use of outdated or inappropriate documents. 170
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Appendix A
(Suggestive Appendix)
Illustration of safety characteristics of irradiation device
1…-Water cooler; 2--Irradiation room ventilation system; 3--Irradiation room monitoring probe; 4--Safety delay alarm; 5--Emergency stop device, 6--Heat and smoke sensor, 7--Normal water level control; 8--Abnormal water level control; 9--Source elevator; 10--"Source down" switch; 11--Roof plug interlock switch; 12--Pool protection, 13--Irradiation room concrete shield; 14--"Source up" switch, 15--Source pool, 16--Safety delay key switch; 17--Exhaust inlet; 18--Personnel and product entry/exit maze; 19--Radiation warning light; 20--"Source moving" light; 21--Product Product entry/exit door? 22—Product entry/exit channel; 23 Product exit monitoring, 24—Source elevator power off 125—Source position check: 26—Interlocked personnel entrance door: 27--Irradiation room monitor with signal; 28--Seismic detector; 29-Single multi-purpose key connected to portable measuring instrument; 30-Control console 31-Water regulator Figure A1 Illustration of safety characteristics of irradiation device
Appendix B
(Suggested appendix)
Calculation of ozone exclusion in irradiation transformer
The following formula is recommended to calculate the ozone generation rate in the entire irradiation room n=5.206×1092HV (ozone molecules/h). (B1)
Where: V,-—The volume of the micro-volume element in the irradiation room, m; H;-dose equivalent rate, Sv/h.
When the irradiation device has been running for a long time, that is, the running time is much longer than the effective ventilation time, the indoor ozone concentration reaches the saturation concentration C.
Wherein; C,
GB 17279-1998
-Indoor ozone saturation concentration, mg/m; T. Effective ventilation time, min;
Actual ventilation time, min;
Ozone decomposition time, about 50min.
(B2)
(B3)
When the C. value is greater than the concentration limit of the workplace, personnel are not allowed to enter. At this time, either increase the ventilation frequency or wait for a period of time ta under the original ventilation frequency. ta is calculated by the following formula: ta = Tln
Wherein, the ozone concentration limit C,=0.16mg/m. Appendix C
(Suggested Appendix)
Schematic diagram for calculating the shielding thickness of the reservoir water
Single drill rod
Drill rod assembly
Calculation point 2
Schematic diagram for calculating the water layer thickness of the reservoir water
Calculation point 1
Concrete
Figure C2 Schematic diagram for calculating the shielding of the auxiliary pool
Protective water layer thickness
(B4)
Let the dose equivalent rate reduction factor K be
Where: Ｈ-
GB17279—1998
Appendix D
(Suggested Appendix)
Point source shielding calculation
When the irradiation room has a protective wall, the dose equivalent rate of a certain point outside the room at a distance R from the source, Sv/h; when the irradiation room has no protective wall, the dose equivalent rate of a certain point outside the room at a distance R from the source, Sv/h. The thickness of the protective wall can be determined using the relationship
.
Where: S. —Point source intensity, S-\;
n——Conversion coefficient between ray flux density and air absorption dose rate; Q——Quality factor, for ray Q1.
（D2）
Assuming that the radiation from the 6°Co radiation source is monoenergetic and its energy is equal to 1.25MeV, the flux density equivalent to 2.5×10-2mSv/h is 1300/cm2·s.
Table A1 gives the corresponding relationship between the isotropic point source radiation attenuation factor K and the concrete protective wall thickness value t. As long as the K value is calculated by formula (A1), the required concrete shielding layer thickness value can be found. When other materials such as lead, cast iron, water, etc. are used as protective walls, the Kt corresponding relationship numerical table or curve can be found in the relevant data. Table D1
2×105×1001
1×10%2×105×10
1×10%2×1025×1021×10%
1×102×1055×10%1×102×10%5×10%1×102×1075×107104.1112.2118.3124.3
132.3138.2144.2
152.1158.0163.9
Appendix E
(Suggested Appendix)
Calculation of the protective thickness of the irradiation room roof
The following method is recommended for calculating the thickness of the irradiation room roof. The sky backscatter radiation dose equivalent rate at point P in the figure is estimated according to the following empirical formula:4 Design Changes
When design documents are changed, they must be approved by the same unit that approved the documents or by a specially designated unit. The revision of the documents should be notified to all relevant units and individuals as soon as possible to prevent the use of outdated or inappropriate documents. 170
GB17279—1998
Appendix A
(Suggestive Appendix)
Illustration of safety characteristics of irradiation device
1…-Water cooler; 2--Irradiation room ventilation system; 3--Irradiation room monitoring probe; 4--Safety delay alarm; 5--Emergency stop device, 6--Heat and smoke sensor, 7--Normal water level control; 8--Abnormal water level control; 9--Source elevator; 10--"Source down" switch; 11--Roof plug interlock switch; 12--Pool protection, 13--Irradiation room concrete shield; 14--"Source up" switch, 15--Source pool, 16--Safety delay key switch; 17--Exhaust inlet; 18--Personnel and product entry/exit maze; 19--Radiation warning light; 20--"Source moving" light; 21--Product Product entry/exit door? 22—Product entry/exit channel; 23 Product exit monitoring, 24—Source elevator power off 125—Source position check: 26—Interlocked personnel entrance door: 27--Irradiation room monitor with signal; 28--Seismic detector; 29-Single multi-purpose key connected to portable measuring instrument; 30-Control console 31-Water regulator Figure A1 Illustration of safety characteristics of irradiation device
Appendix B
(Suggested appendix)
Calculation of ozone exclusion in irradiation transformer
The following formula is recommended to calculate the ozone generation rate in the entire irradiation room n=5.206×1092HV (ozone molecules/h). (B1)
Where: V,-—The volume of the micro-volume element in the irradiation room, m; H;-dose equivalent rate, Sv/h.
When the irradiation device has been running for a long time, that is, the running time is much longer than the effective ventilation time, the indoor ozone concentration reaches the saturation concentration C.
Wherein; C,
GB 17279-1998
-Indoor ozone saturation concentration, mg/m; T. Effective ventilation time, min;
Actual ventilation time, min;
Ozone decomposition time, about 50min.
(B2)
(B3)
When the C. value is greater than the concentration limit of the workplace, personnel are not allowed to enter. At this time, either increase the ventilation frequency or wait for a period of time ta under the original ventilation frequency. ta is calculated by the following formula: ta = Tln
Wherein, the ozone concentration limit C,=0.16mg/m. Appendix C
(Suggested Appendix)
Schematic diagram for calculating the shielding thickness of the reservoir water
Single drill rod
Drill rod assembly
Calculation point 2
Schematic diagram for calculating the water layer thickness of the reservoir water
Calculation point 1
Concrete
Figure C2 Schematic diagram for calculating the shielding of the auxiliary pool
Protective water layer thickness
(B4)
Let the dose equivalent rate reduction factor K be
Where: Ｈ-
GB17279—1998
Appendix D
(Suggested Appendix)
Point source shielding calculation
When the irradiation room has a protective wall, the dose equivalent rate of a certain point outside the room at a distance R from the source, Sv/h; when the irradiation room has no protective wall, the dose equivalent rate of a certain point outside the room at a distance R from the source, Sv/h. The thickness of the protective wall can be determined using the relationship
.
Where: S. —Point source intensity, S-\;
n——Conversion coefficient between ray flux density and air absorption dose rate; Q——Quality factor, for ray Q1.
（D2）
Assuming that the radiation from the 6°Co radiation source is monoenergetic and its energy is equal to 1.25MeV, the flux density equivalent to 2.5×10-2mSv/h is 1300/cm2·s.
Table A1 gives the corresponding relationship between the isotropic point source radiation attenuation factor K and the concrete protective wall thickness value t. As long as the K value is calculated by formula (A1), the required concrete shielding layer thickness value can be found. When other materials such as lead, cast iron, water, etc. are used as protective walls, the Kt corresponding relationship numerical table or curve can be found in the relevant data. Table D1
2×105×1001
1×10%2×105×10
1×10%2×1025×1021×10%
1×102×1055×10%1×102×10%5×10%1×102×1075×107104.1112.2118.3124.3
132.3138.2144.2
152.1158.0163.9
Appendix E
(Suggested Appendix)
Calculation of the protective thickness of the irradiation room roof
The following method is recommended for calculating the thickness of the irradiation room roof. The sky backscatter radiation dose equivalent rate at point P in the figure is estimated according to the following empirical formula:The flux density of 5×10-2mSv/h is 1300/cm2·s.
Table A1 gives the corresponding relationship between the isotropic point source ray attenuation factor K and the concrete protective wall thickness value t. As long as the K value is calculated by formula (A1), the required concrete shielding layer thickness value can be found. When other materials such as lead, cast iron, water, etc. are used as protective walls, the Kt corresponding relationship numerical table or curve can be found in the relevant data. Table D1
2×105×1001
1×10%2×105×10
1×10%2×1025×1021×10%
1×102×1055×10%1×102×10%5×10%1×102×1075×107104.1112.2118.3124.3
132.3138.2144.2
152.1158.0163.9
Appendix E
(Suggested Appendix)
Calculation of the protective thickness of the irradiation room roof
The following method is recommended for calculating the thickness of the irradiation room roof. The sky backscatter radiation dose equivalent rate at point P in the figure is estimated according to the following empirical formula:The flux density of 5×10-2mSv/h is 1300/cm2·s.
Table A1 gives the corresponding relationship between the isotropic point source ray attenuation factor K and the concrete protective wall thickness value t. As long as the K value is calculated by formula (A1), the required concrete shielding layer thickness value can be found. When other materials such as lead, cast iron, water, etc. are used as protective walls, the Kt corresponding relationship numerical table or curve can be found in the relevant data. Table D1
2×105×1001
1×10%2×105×10
1×10%2×1025×1021×10%
1×102×1055×10%1×102×10%5×10%1×102×1075×107104.1112.2118.3124.3
132.3138.2144.2
152.1158.0163.9
Appendix E
(Suggested Appendix)
Calculation of the protective thickness of the irradiation room roof
The following method is recommended for calculating the thickness of the irradiation room roof. The sky backscatter radiation dose equivalent rate at point P in the figure is estimated according to the following empirical formula:
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