GB 15146.10-2001 Safety requirements for the application of fixed neutron absorbers for nuclear criticality safety of fissile materials outside reactors

This standard specifies the application safety requirements of fixed neutron absorbers as an integral part of nuclear facilities and fissile material process equipment outside the reactor and providing nuclear criticality safety control. This standard applies to the design, manufacture and operation of facilities for handling, processing, handling and storing fissile materials. This standard also applies to equipment related to the transportation of fissile materials. GB 15146.10-2001 Application safety requirements for fixed neutron absorbers for nuclear criticality safety of fissile materials outside the reactor GB15146.10-2001 Standard download decompression password: www.bzxz.net

GB15146.10--2001
7.1.2 and 7.1.3 of this standard are recommended, and the rest are mandatory. Fixed neutron absorbers can be used as one of the nuclear criticality control measures in many cases to ensure the subcriticality safety margin required under normal and abnormal operating conditions, so that the facilities or equipment can be used more economically and effectively. GB15146.2-1994 "Basic Technical Criteria and Subcritical Limits for Nuclear Criticality Safety of Fissile Materials Outside Reactors and Operation, Processing and Treatment of Fissile Materials" makes general provisions for the use of neutron absorbers for nuclear criticality safety control. This standard supplements the relevant requirements in GB15146.2-1994 and GB15146.8-1994 "Nuclear Criticality Safety of Fissile Materials Outside Reactors and Nuclear Criticality Safety Criteria for Operation, Storage and Transportation of Light Water Reactor Fuel Units outside Reactors", and puts forward more detailed safety requirements for the application of fixed neutron absorbers in the design, construction and operation of nuclear facilities outside reactors. In this standard, the so-called fixed neutron absorber refers to a neutron absorber that is an organic part of a facility, equipment or fuel component and plays a role in nuclear criticality safety control as required. This standard is compiled with reference to the American national standard ANSI/ANS-8.211995 "Application of fixed neutron absorbers in non-reactor nuclear facilities". Its technical content is equivalent to the latter, but necessary adjustments have been made in terms of structure, and the referenced standards have been replaced with the corresponding standards of my country.
This standard was proposed by China National Nuclear Corporation. The drafting unit of this standard: Nuclear Industry Standardization Research Institute. The main drafter of this standard: Qiao Fengguan.
National Standard of the People's Republic of China
Safety requirements for the use of fixed neutron absorbers for nuclear criticality safety of fissile materials outside reactorsNuclear criticality safety for fissile materials outside reactorsSafety requirements for the use of fixed neutron absorbers1Scope
GB 15146. 10--2001
This standard specifies the safety requirements for the use of fixed neutron absorbers as an integral part of nuclear facilities outside reactors and fissile material process equipment, and providing nuclear criticality safety control. This standard applies to the design, construction and operation of facilities for handling, processing, handling and storing fissile materials. This standard also applies to equipment related to the transportation of fissile materials.
2Cited 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 parties using this standard should explore the possibility of using the latest versions of the following standards. GB15146.1-1994 Nuclear criticality safety of fissile materials outside reactors Nuclear criticality safety administrative regulations GB15146.2-1994 Nuclear criticality safety of fissile materials outside reactors Basic technical criteria and subcritical limits for the operation, processing and treatment of fissile materials
HAF0400 (91) Safety regulations for quality assurance of nuclear power plants 3 Definitions
This standard adopts the following definitions.
3. Nuclear criticality safetynuclear criticality safetyMeasures to prevent nuclear criticality accidents and mitigate the consequences of nuclear criticality accidents, the most fundamental of which is the measures to prevent accidental neutron chain reactions.
neutron absorber.
3.2 Neutron absorber
Material that can capture neutrons.
3.3 Fixed neutron absorberFixed neutron absorberA solid neutron absorber that has a given geometric relationship with the location of the fissile material. 3.4 Moderator
Material that reduces the energy of neutrons by scattering them. 3.5 Fixed moderator A moderator that forms a predetermined geometric relationship with the fixed neutron absorber and the location of the fissile material. 3.6 Neutron absorber system Any combination of fixed neutron absorbers, fixed moderators and other materials with a known nuclear criticality safety function. 3.7 Benchmark experiment Approved by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China on October 24, 2001 and implemented on April 1, 2002
GB 15146. 10---2001
An experiment suitable for verifying the calculation method used to evaluate the effectiveness of the neutron absorber system. 3.8 Validation
The process of using experimental results to confirm whether the analytical method used to evaluate the effectiveness of the neutron absorber system for nuclear criticality control meets the predetermined requirements. Www.bzxZ.net
3.9 Verification
The authenticity or correctness of a fact is determined or confirmed by investigation, comparison with a certain standard or review of multiple similar facts. 3.10 In-service verification The regular verification of the integrity of the neutron absorber system after its installation. 4 General safety requirements
4.1 The purpose of using fixed neutron absorbers in nuclear criticality control is to ensure the subcriticality of the facility or equipment under normal and credible abnormal conditions throughout its operating life. The basic requirements for nuclear criticality safety administration specified in GB15146.1 and the basic technical criteria for nuclear criticality safety specified in GB15146.2 must be followed. Before selecting a certain absorber material, the absorber made of this material and its effectiveness in capturing neutrons must be verified. After the neutron absorber system is installed, verification must be carried out to ensure that the neutron absorber system is in the intended position. The content, depth and frequency of verification must be determined based on the environmental conditions of the absorber, the properties of the absorber material and the configuration of the absorber system. When determining the effectiveness of neutron absorbers, applicable experimental data or analytical methods that have been verified with the help of appropriate benchmark experiments must be applied. For various specific applications, the selection and protection of materials must be compatible with the neutron absorption requirements of the designed facility during normal and credible abnormal conditions. If the moderator or structural materials in the neutron absorber system are required for nuclear criticality safety, these materials must also be controlled, analyzed and verified in accordance with the provisions of the following chapters. 4.2 For each activity specified in this standard, a quality assurance program that meets the relevant requirements specified in HAF0400 (91) must be established and implemented.
5 Design requirements
5.1 The design must ensure that the neutron absorber system always maintains its required geometric relationship with the fissile material during the expected operating life.
5.1.1 Verification means must be provided to determine that all components of the neutron absorber system meet the design, safety and operating requirements. The design of the neutron absorber system must also take into account the in-service verification requirements. 5.1.2 The design must include an evaluation of the operating environment conditions. During the design process, measures must be taken to protect the neutron absorber or the protective materials that protect the neutron absorber to prevent their performance from being degraded due to chemical, physical, radiation and mechanical effects, or to keep such degradation within the allowable range.
5.1.2.1 The design must ensure that the fixed neutron absorber maintains the required neutron absorption capacity during its expected operating life (including under all credible neutron moderation and reflection conditions). 5.1.2.2 The effects of radiation on the neutron absorber system during the expected operating life must be evaluated, such as depletion caused by neutron absorption, embrittlement and radiation.
5.1.3 The design must take into account the differences in process materials, manufacturing tolerances, uncertainties in absorber density and distribution, and uncertainties in the nuclear characteristics of the neutron absorber (such as neutron cross section), and leave appropriate safety margins. 5.2 The design must ensure that the nuclear criticality safety function of the neutron absorber system is not compromised by all credible operating operations and natural events that may occur to the facility or equipment.
5.3 The design of the neutron absorber system must prevent its components from being accidentally removed, moved or altered. 5.4 The design of facilities and equipment containing fixed neutron absorbers must appropriately apply the principles of human factors engineering for the installation, operation and maintenance of fixed neutron absorbers.
5.5 The design of the fixed neutron absorber system must take into account the operation requirements, the account balance requirements of fissile materials and other relevant safety issues.
6 Safety evaluation
GB 15146. 10—-2001
6.1 The safety evaluation of the neutron absorber system must comply with GB15146.1-1994 Chapter 5 of the basic requirements for nuclear criticality safety analysis and evaluation.
6.1.1 The possibility of neutron absorber performance degradation caused by physical or chemical effects, changes in any material components and changes in the neutron absorber system's own materials (such as cladding materials) under normal operating environment conditions must be evaluated. 6.1.2 The impact of various credible adverse environmental conditions and operating conditions on the neutron absorber system must be evaluated, such as radiation damage, depletion, chemical reactions, temperature changes, pressure conditions, vibration, mechanical shock, abrasion, corrosion, accidental removal, fire and flooding. 6.1.3 After any event that causes the physical or chemical conditions of the neutron absorber system to exceed the design range, the system must be re-evaluated before starting a new operation.
6.2 The safety analysis must be based on the results given by a verified calculation method or the results given by applicable experiments. The calculation method must be verified in accordance with the provisions of GB15146.2. 6.2.1 The calculation method used must be able to reflect the neutron flux density depression effect associated with the local neutron absorber. 6.2.2 The impact of the non-uniformity of the fixed neutron absorber (such as neutron leakage through the neutron absorber material) on nuclear criticality must be evaluated. 6.3 The evaluation must take into account manufacturing tolerances, material substitutions, geometric changes, corrosion allowances, model assumptions, process variables and other relevant uncertainties.
7 Verification and Inspection
7.1 The verification and inspection plan of the neutron absorber system must be incorporated into the operational quality assurance requirements of the facility. Any verification and inspection activities must not jeopardize the nuclear critical safety of the operating system. The verification and inspection must be documented and the relevant records must be kept until the end of the operating life of the facility and the neutron absorber system.
7.1.1 The content, depth and frequency of the required in-service verification and inspection must be determined; factors to be considered include safety analysis, environmental conditions in which the absorber is located and the characteristics of the absorber material. 7.1.2 When necessary, the methods used to measure the characteristics of the absorber may include neutron technology, other non-destructive testing techniques or chemical testing methods. 7.1.3 The inspection methods used to verify the characteristics of the neutron absorber should be calibrated using material standards that can be traced back to national benchmarks. 7.2 The procurement of neutron absorber materials, the manufacture of neutron absorber system components, and the installation, operation and maintenance of the neutron absorber system must all be subject to a verification and inspection plan. 7.2.1 Before adoption, the elemental data or isotope data of the neutron absorber material must be verified. 7.2.2 Before actual installation, it must be verified that the components of the neutron absorber system are consistent with their design drawings and technical specifications. 7.2.3 Before being put into operation, it must be verified that the neutron absorber system is correctly installed. 7.2.4 It must be verified that the operation and maintenance of the neutron absorber system meet the safety assessment requirements. 7.3 The results of the in-service verification must be evaluated; appropriate corrective measures must be taken when necessary. 201
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