A 3D Simulation Calculation Method for Nonlinear Characteristics of Fuel Assembly Compression System

A non-linear feature, fuel assembly technology, used in design optimization/simulation, special data processing applications, etc., can solve the problems of inaccurate load calculation of the compaction system, and failure to consider the critical radiation effect, etc., to reduce Failure risk, achieve accurate calculation, improve safety effect

Active Publication Date: 2021-03-19
NUCLEAR POWER INSTITUTE OF CHINA
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

[0004] The technical problem to be solved by the present invention is: the inaccurate calculation of the load of the compaction system due to the fact that the prior art does not consider the radiation effect that is crucial to the influence of the fuel assembly and its compaction system, and the purpose is to provide a fuel assembly The three-dimensional simulation calculation method of the nonlinear characteristics of the compaction system can accurately and effectively calculate the compaction load in the middle and late stages of the life of the fuel assembly

Method used

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  • A 3D Simulation Calculation Method for Nonlinear Characteristics of Fuel Assembly Compression System
  • A 3D Simulation Calculation Method for Nonlinear Characteristics of Fuel Assembly Compression System
  • A 3D Simulation Calculation Method for Nonlinear Characteristics of Fuel Assembly Compression System

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Embodiment 1

[0039] A three-dimensional simulation calculation method for the nonlinear characteristics of the fuel assembly compaction system, based on the commercial software ANSYS, specifically for figure 1 The plate spring compression system shown, its calculation process is as follows image 3 shown, including:

[0040] 1) Simulation of irradiation growth

[0041] The macroscopic experimental model of fuel assembly irradiation growth rate and fast neutron fluence is shown in formula (1), and the fast neutron fluence at the position of the fuel assembly compression system at the corresponding burnup time obtained by combining with the reactor physical design calculation The irradiation growth rate of the fuel assembly can be obtained. Then, according to formula (2), the influence of radiation growth on the deformation of the compaction system is obtained, that is, the simulation of radiation growth of fuel assemblies is realized.

[0042]

[0043] In the formula, a, b, c and d a...

Embodiment 2

[0067] The only difference between this embodiment and Embodiment 1 is that the simulation of the radiation relaxation of the fuel assembly pressing system is realized by modifying the constitutive relation of the material, such as Figure 4 , that is, the stress σ is the strain ε, the fast neutron fluence and the function of fast neutron energy E:

[0068]

[0069] in,

[0070] σ 0 =f(ε) (6)

[0071]

[0072] In the formula, σ 0 In order to consider the stress after radiation relaxation, ε is the strain, and f(ε) is not affected by radiation relaxation, the same as in the embodiment 1 ; σ is the stress after radiation relaxation is taken into account; j is the number of fast neutron groups subjected to the compaction system; is the i-th fast neutron fluence received by the compaction system; E i is the average energy of group i fast neutrons received by the compaction system; G1, G2, G3, G4 are radiation relaxation correlation coefficients. For this fuel assemb...

Embodiment 3

[0074] The difference between this embodiment and Embodiment 1 is that the only difference between this embodiment and Embodiment 1 and Embodiment 2 is that the calculated fuel assembly system can also adopt other spring structures other than the plate spring compression system, which can be a helical Spring compression system, disc spring compression system, torsion bar spring compression system, other spring compression systems or a compression system in which the aforementioned multiple springs are combined with each other.

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Abstract

The invention discloses a three-dimensional simulation calculation method for the nonlinear characteristics of a fuel assembly compaction system, which solves the problem that the prior art does not consider the radiation effect that is critical to the influence of the fuel assembly and its compaction system, resulting in inaccurate calculation of the load of the compaction system. exact question. The present invention includes: performing three-dimensional simulation for four types of nonlinear phenomena in the compaction system, namely, geometric nonlinearity, material nonlinearity, state nonlinearity and radiation effect, and obtaining the compression force at the corresponding moment in the life of the compaction system through three-dimensional coupled numerical analysis. tight load. The invention has the advantages of being able to realize the calculation of the pressing load at any time in the whole life of the pressing system, and improving the safety, reliability and economy of the fuel assembly.

Description

technical field [0001] The invention relates to the field of simulation calculation of a reactor fuel assembly compression system, in particular to a three-dimensional simulation calculation method for nonlinear characteristics of the fuel assembly compression system. Background technique [0002] Existing reactor fuel assemblies usually consist of a number of fuel rods, guide tubes, spacer grids, lower nozzle parts, and upper nozzle parts containing a compression system, such as figure 1 shown. The compression system is arranged on the top of the fuel assembly, axially compresses the fuel assembly, keeps it in contact with the lower core plate, and compensates for the radiation growth of the fuel assembly and the thermal expansion difference of the fuel assembly relative to the internal components. If the load of the compression system is too small, the fuel assembly cannot be compressed, and if it is too large, it will cause the fuel assembly to bend and affect the contro...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06F30/20
CPCG06F30/20
Inventor 蒲曾坪庞华张吉斌茹俊张林柴晓明秦勉齐敏马超
Owner NUCLEAR POWER INSTITUTE OF CHINA
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