This standard specifies the nuclear criticality safety technical criteria and technical conditions for the transfer of steel pipelines containing uranium or plutonium homogeneous aqueous solutions. It does not involve specific information on chemistry, mechanical technology, fluid dynamics or other engineering principles required for the safe design of process equipment. This standard applies to the transfer of steel pipelines encountered during the storage, transportation and treatment of uranium or plutonium homogeneous aqueous solutions. GB 15146.4-1994 Nuclear criticality safety of fissile materials outside reactors Nuclear criticality safety criteria for the transfer of steel pipelines containing fissile material aqueous solutions GB15146.4-1994 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Nuclear criticality safety for fissile materials outside reactor-Nuclear criticality safety criteria for steel-pipe intersectionscontaining aqueous solutions of fissile material1Subject content and scope of application
GB15146.4—94
This standard specifies the technical criteria and technical conditions for nuclear criticality safety for steel-pipe intersections containing aqueous solutions of fissile material. It does not involve specific information on chemistry, mechanical technology, fluid dynamics or other engineering principles required for the safe design of process equipment. This standard applies to the intersection of steel pipes encountered during the storage, transportation and processing of uranium or uranium-containing aqueous solutions. 2 Reference standards
GB15146.1 Nuclear criticality safety of fissile materials outside reactors Nuclear criticality safety administrative regulations GB15146.2 Nuclear criticality safety of fissile materials outside reactors Basic technical criteria and subcritical limits for the operation, processing and treatment of fissile materials
3 Terms
3.1 Main pipe
The straight pipe with the largest diameter in the connecting pipe system (see Figure 1). 3.2 Pipe section
Any section of the main pipe with a length of 0.5m (see Figure 1). 3.3 Branch pipebzxZ.net
The pipe connecting to the main pipe (see Figure 1).
3.4 ​​Straight fan
The area enclosed by two mutually perpendicular half planes with the pipe section axis as the intersection line and the pipe section surface (see Figure 1). 3.5 Intersection area
The area of ​​solution in the branch pipe cut by the main pipe section at the intersection of the branch pipe axis and the main pipe surface (see Figure 2). 3.6 Environmental factors
Usually not directly related to the process but affecting the system subcritical margin and environmental conditions that may change, such as personnel, tools, etc.
3.7 Perfect reflector
A reflector that is close to the piping system and whose reactivity contribution is equivalent to that of an infinitely thick layer of water. 3.8 Intermediate reflector
A neutron reflector whose reactivity contribution to a main pipe with branches does not exceed the corresponding contribution of the reflection condition to the main pipe when both the wall and the floor are 30 cm thick concrete, a 2m×2m small room, and one concrete wall is in contact with the main pipe and the branch pipe (see Figure 3). 3.9 Partial reflector
- A neutron reflector whose reactivity contribution to a main pipe with a branch pipe does not exceed the corresponding contribution to the main pipe under the reflection condition of a 2m×2m chamber with 30cm thick concrete walls and floor and the fissile material is more than 30cm away from each concrete wall and floor (see Figure 4).
Figure 1 Schematic diagram of main pipe, pipe section, branch pipe, and straight fan Reflection wall
Concrete
Axis of branch pipe
Intersection area
At pipe section
Main pipe section
Figure 2 Intersection area
Figure 3 Medium reflector
Concrete
Figure 4 Partial reflector
4 General criteria
GB 15146.4—94
Reflection wall
Shortest line segment
Prohibited straight fan
Section plane
Intersection area
Section of main pipe
Figure 5 Prohibited straight fan of medium reflector
4.1 All operations related to this standard for fissile aqueous solutions must comply with the relevant requirements of GB15146.1 and GB15146.2. 4.2 This standard only makes criticality safety technical provisions for the intersection of single-pipe main pipes. The influence of multiple main pipes or main pipes with other fissile materials nearby and their environmental factors on these systems must be determined by experiments or verified calculation methods. 4.3 Appropriate precautions must be taken to ensure the quality of equipment installation and operation, and to control the moderator and adjacent fissile materials so that the specified parameters on which nuclear criticality safety depends are valid. 5 Technical regulations for pipeline connection
Tables 1 to 4 give the technical regulations for pipeline connection of uranium or cyclic water solution for three types of neutron reflectors1. The wall thickness of the pipelines in Tables 1 to 4 must be less than the corresponding wall thickness listed in Table 5. Tables 1 to 4 do not limit the length of the main pipe or the number of pipe sections equipped with branches. The main pipe composed of an unlimited number of pipe sections must be subcritical. Note: 1) Calculations have been made for the pipeline connection of the three types of reflectors listed in Tables 1 to 4. The results show that the sub-multiplication factor is not greater than 0.85 for the pipeline connection of medium and partial reflectors, and the sub-multiplication factor is not greater than 0.90 for the pipeline connection of complete reflectors. 5.1 Reflectors
The technical regulations for pipeline connection must be determined according to the reflector. The type of reflector of the main pipe must be determined according to its location and environmental factors.
5.1.1 Each pipe section must comply with the corresponding technical regulations given in Tables 1 to 4 for the selected reflectors, including the pipe size, the number of straight sectors with branches allowed on each pipe section, and the number of branches allowed on each straight sector. 5.1.2 Mains with a distance of more than 30 cm from the wall must meet the technical regulations for partial reflectors. 5.1.3 Mains with a distance of 30 cm or less from the wall must meet the technical regulations for medium reflectors, but branches must not intersect with the mains on prohibited straight sectors. Prohibited straight sectors refer to straight sectors that are equally divided by the half plane drawn from the main axis and in which the shortest line segment from the main surface to the wall is located under the reflection of the medium reflector (see Figure 5). 5.1.4 Mains immersed in water or with hydrogen-containing materials between branches must meet the technical regulations for complete reflectors. 5.2 Uranium aqueous solution
The technical provisions of Tables 1 to 3 apply to aqueous solutions with any uranium-235 content and uranium-233 content not exceeding 1% (weight) of the total uranium content. When the uranium-235 content of the uranium aqueous solution is not more than 5% (weight) of the total uranium content and the uranium-233 content is not more than 0.05% (weight) of the total uranium content, the technical provisions of Table 4 can replace the technical provisions of Tables 1 to 3. 5.3 Cyclone aqueous solution
The technical provisions of Tables 1 to 3 apply to cyclone aqueous solution with a cyclone concentration not exceeding 400g/L and a cyclone-241 content not exceeding the cyclone content of cyclone-240
6 Application of the requirements of this standard
GB15146.494
For pipeline handovers that apply the technical provisions of Tables 1 to 4, the following requirements of 6.1 to 6.4 must be verified based on the type of fissile material and the evaluated reflector.
6.1 It must be verified that the environmental factors of the process operation do not contribute more to the reactivity of the main pipe than the selected reflector 1. The pipe size should be appropriately selected to compensate for possible changes in the reflector. Note: 1) For partial and medium reflectors, the ke of the pipe connection system should not be greater than 0.85; for complete reflectors, the k of the pipe connection system should not be greater than 0.90.
6.2 The maximum intersection area of ​​each straight fan body specified in Tables 1 to 4 (that is, the sum of the intersection areas of all branches) shall not exceed. The number of branches on each straight fan body can be reduced or the diameter of the branch pipe can be reduced in the case of only one branch pipe, so as not to exceed the specified maximum allowable intersection area. The technical provisions of Tables 1 to 4 are proposed for orthogonal intersections, but the angle between the axis of the main pipe and the axis of the branch pipe can vary between 30° and ~90°.
6.3 Regardless of the total intersection area of ​​each straight fan body, the number of branches on each straight fan body specified in Tables 1 to 4 shall not be increased. 6.4 The minimum spacing between branches in a straight fan shall not be less than the spacing when the branches are equally spaced according to the maximum number of branches allowed. Table 1 Technical regulations for the connection of pipelines containing uranium or cyclic water with partial reflectors Pipeline size"\, cm
Outer diameter of main pipe
Outer diameter of branch pipe
Maximum
Allowable connection area for each branch
Number of straight fans with branches allowed on each pipe section
Number of branches allowed on each straight fan
GB 15146.4—94
Continued Table 1
Number of branches allowed on each straight fan
Number of straight fan bodies with branches allowed on each pipe section
Maximum
allowable intersection area of ​​each branch
Pipeline size\, cm
Outer diameter of branch pipe
Outer diameter of main pipe
GB15146.4--94
Note: 1) For uranium-water solution, when the uranium-233 content does not exceed 1% of the total uranium weight, it is applicable to clamps with any uranium-235 content. For anion-water solution, it is applicable to anion with an anion concentration not exceeding 400g/L and anion-240 content greater than anion-241. 2) The pipe wall thickness is the corresponding thickness listed in Table 5 or thicker. Table 2 Technical regulations for pipe connection of uranium-containing or anion-water solution 1 with medium reflectors
Allowable number of branches on each straight sector2)3)
Number of straight sectors with branches\)
Allowed installation on each pipe section
Maximum
Allowable connection area for each branch
Outer diameter of branch
Pipeline size2, cm
Outer diameter of main pipe
Pipeline size2, cm
Outer diameter of main pipe
|Outer diameter of branch pipe
GB15146.4-94
Continued Table 2
Maximum
Allowable intersection area of ​​each branch pipe
Number of branch pipe straight sectors allowed to be installed on each pipe section3)
On each straight sector,
Allowable number of branches\))
Note; 1) For uranium aqueous solution, when the content of uranium-233 does not exceed 1% of the total uranium weight, it is applicable to uranium with any content of uranium-235. For uranium aqueous solution, it is applicable to uranium with a concentration of uranium not exceeding 400g/1. and a content of uranium-240 greater than uranium-241. 2) The wall thickness of the pipeline is the corresponding thickness listed in Table 5 or thicker. 3) For prohibited straight sectors, refer to 5.1.3 and Figure 4. Table 3 Uranium-containing or uranium-containing water solutions with complete reflectors 1 Technical regulations for pipe connection Pipeline size, cm
Outer diameter of main pipe
Outer diameter of branch pipe
Maximum
Allowable connection area for each branch
Number of branch pipe straight sectors allowed to be installed on each pipe section
Note: 1) For uranium-containing water solutions, when the uranium-233 content does not exceed 1% of the total uranium weight, it is applicable to any uranium-235 content. For uranium-containing water solutions, it is applicable to uranium concentrations not exceeding 400g/L and the uranium-240 content is greater than uranium-241. 2) The pipe wall thickness is the corresponding thickness listed in Table 5 or thicker. Permissible number of branches on each straight fan
Uranium-water solution with a maximum uranium-235 content of 5% (weight) 1 Technical regulations for pipeline connection Table 4
Pipeline size\, cm
Branch outer diameter
Maximum allowable
Connection area of ​​each branch
Partial reflector
Number of straight fans with branches allowed on each pipe section
Each straight fan
The number of branches allowed on the pipe body Medium reflector A straight fan The number of branches allowed on each pipe section The number of straight fans allowed on each pipe section The number of branches allowed on the pipe body 3) Full reflector The number of straight fans allowed on each pipe section The number of branches allowed on each fan GB 15146.4-94 Note: 1) The content of -233 shall not exceed 0.05% of the total weight. 2) The wall thickness of the pipe shall be the corresponding thickness listed in Table 5 or thicker. 3) For prohibited straight fan bodies, please pay attention to 5.1.3 and Figure 4. 5 Outer diameter and wall thickness of stainless steel pipes
4.8(4.83)
6.0(6.03)
7.3(7.30)
8.5(8.89)
10.0(10. 16)
11.4(11.43)
14.0(14.13)
16.8(16.83)
21.9(21.91)
27. 3(27. 31)
Note: ① The outer diameter and wall thickness are both nominal values. ② The numbers in brackets are the corresponding values ​​of American standard pipes. Additional notes:
This standard is proposed by China National Nuclear Corporation. This standard was drafted by the Second Research and Design Institute of Nuclear Industry. The main drafter of this standard is Wang Weishan.
This standard is equivalent to the American National Standard ANSI/ANS8.9-1987.162
0. 28(0. 277)
0. 28(0. 277)
0.32(0.305)
0.32(0.305)
0. 32(0.305)
0.35(0.305)
0.35(0.305)
0.37(0.340)
0.38(0.376)
0.429(0.419)31)
Note: ① The outer diameter and wall thickness are nominal values. ② The numbers in brackets are the corresponding values ​​of American standard pipes. Additional notes:
This standard was proposed by China National Nuclear Corporation. This standard was drafted by the Second Research and Design Institute of Nuclear Industry. The main drafter of this standard is Wang Weishan.
This standard is equivalent to the American national standard ANSI/ANS8.9-1987. 162
0. 28(0. 277)
0. 28(0. 277)
0.32(0.305)
0.32(0.305)
0. 32(0.305)
0.35(0.305)
0.35(0.305)
0.37(0.340)
0.38(0.376)
0.429(0.419)31)
Note: ① The outer diameter and wall thickness are nominal values. ② The numbers in brackets are the corresponding values ​​of American standard pipes. Additional notes:
This standard was proposed by China National Nuclear Corporation. This standard was drafted by the Second Research and Design Institute of Nuclear Industry. The main drafter of this standard is Wang Weishan.
This standard is equivalent to the American national standard ANSI/ANS8.9-1987. 162
0. 28(0. 277)
0. 28(0. 277)
0.32(0.305)
0.32(0.305)
0. 32(0.305)
0.35(0.305)
0.35(0.305)
0.37(0.340)
0.38(0.376)
0.429(0.419)
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