7.1.2 and 7.1.3 of this standard are recommendatory, and the rest are compulsory.
Fixed neutron absorbers are frequently used as part of the overall nuclear criticality control measures to ensure the subcritical safety margin required under normal and abnormal operating conditions, so that the facilities or equipment function more economically and effectively.
GB 15146.2-1994 Nuclear criticality safety for fissile materials outside reactor - Basic technical practices and subcritical limits for handling, processing and operations of fissile materials sets forth general requirements for nuclear criticality safety control with neutron absorbers. This standard supplements the relevant requirements in GB 15146.2-1994 and GB 15146.8-1994 Nuclear criticality safety for fissile materials outside reactors - Criticality safety criteria for the handling, storage, and transportation of LWR fuel unit outside reactors, and provides more detailed safety requirements for the use of fixed neutron absorbers in the design, construction and operation of non-reactor nuclear facilities. In this standard, the so-called fixed neutron absorber refers to the neutron absorber which is an integral part of the facility, equipment or fuel component and plays the role of nuclear criticality safety control as required.
This standard is prepared with reference to American national standard ANSI/ANS-8. 21-1995 Use of Fixed Neutron Absorbers in Nuclear Facilities Outside Reactors. Its technical content is equivalent to the latter, but necessary adjustments have been made in terms of the structure, and the normative references have been replaced by the corresponding standards of China.
This standard was proposed by China National Nuclear Corporation.
Drafting organization of this standard: Institute for Standardization of Nuclear Industry.
Chief drafter of this standard: Zhuo Fengguan.
Nuclear criticality safety for fissile materials outside reactors - Safety requirements for the use of fixed neutron absorbers
1 Scope
This standard provides guidance for the use of fixed neutron absorbers as an integral part of nuclear facilities and fissionable material process equipment outside reactors, where such absorbers provide nuclear criticality safety control.
This standard is applicable to the design, construction and operation of facilities for the operation, processing, treatment and storage of fissile materials. This standard is also applicable to equipment related to the transport of fissile materials.
2 Normative references
The following standards contain provisions which, through reference in this standard, constitute provisions of this standard. At the time of publication, all editions listed are valid. All standards are subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below.
GB 15146.1-1994 Nuclear criticality safety for fissile materials outside reactors - Administrative regulation for nuclear criticality safety
GB 15146.2-1994 Nuclear criticality safety for fissile materials outside reactors - Basic technical criteria and subcritical limits for handling, processing and operations of fissile materials
HAF 0400 (91) Safety specifications for quality assurance of nuclear power plant
3 Definitions
For the purposes of this standard, the following definitions apply.
3.1
nuclear criticality safety
prevention of nuclear criticality accidents and protection against the consequences thereof, preferably by prevention of inadvertent nuclear chain reaction
3.2
neutron absorber
neutron-capture material
3.3
fixed neutron absorber
neutron absorbers in solids with an established geometric relationship to the locations occupied by fissionable material
3.4
moderator
material that reduces the energy of neutrons by scattering them
3.5
fixed moderator
moderator with an established geometric relationship to the locations occupied by the fixed neutron absorber and fissionable material
3.6
neutron absorber system
any combination of fixed neutron absorbers, fixed moderators, and other materials with an assigned nuclear criticality safety function
3.7
benchmark experiment
experiment appropriate for the validation of calculational methods applicable to the evaluation of the neutron absorber system
3.8
validation
process of using experimental results to demonstrate that the analytical methods used to compute the effectiveness of the neutron absorber systems for criticality control meet predetermined requirements
3.9
verification
establishment or confirmation of the truth or accuracy of a fact by investigation, comparison with a standard, or reference to the facts
3.10
in-service verification
periodic verification of the integrity of the neutron absorber system subsequent to installation
Foreword i 1 Scope 2 Normative references 3 Definitions 4 General safety considerations 5 Design requirements 6 Safety evaluations 7 Verification and inspection
ICS 27.120.30 F 09 GB 15146.10—2001 反应堆外易裂变材料的核临界安全 固定中子吸收体的应用安全要求 Nuclear criticality safety for fissile materials outside reactors Safety requirements for the use of fixed neutron absorbers 2001-10-24发布 2002-04-01实施 中华人民共和国国家质量监督检验检疫总局发布 前 言 本标准7.1.2、7.1.3为推荐性的，其余为强制性的。 固定中子吸收体在许多场合可被用作核临界控制措施之一，用以确保正常和异常运行操作条件下所需要的次临界安全裕度，使更加经济有效地发挥设施或设备的作用。 GB 15146.2—1994《反应堆外易裂变材料的核临界安全 易裂变材料操作、加工、处理的基本技术准则与次临界限值》对利用中子吸收体进行核临界安全控制作了一般规定。本标准补充了GB 15146.2—1994以及GB 15146.8—1994《反应堆外易裂变材料的核临界安全 堆外操作、贮存、运输轻水堆燃料单元的核临界安全准则》中的有关要求，对固定中子吸收体在反应堆外核设施的设计、建造和运行中的应用提出了更加详细的安全要求。在本标准中，所谓固定中子吸收体是指作为设施、设备或燃料部件的有机组成部分并按要求发挥核临界安全控制作用的中子吸收体。 本标准参考美国国家标准ANSI/ANS-8.21—1995《固定中子吸收体在非反应堆核设施中的应用》编制而成，其技术内容与后者等效，但在结构方面作了必要的调整，并将引用标准替换为我国的相应标准。 本标准由中国核工业总公司提出。
