Leak before burst analysis method based on failure assessment diagram

An analysis method and load technology, applied in special data processing applications, instruments, electrical digital data processing, etc., to achieve the effect of a wide range of applications

Active Publication Date: 2018-10-26
SUZHOU NUCLEAR POWER RES INST +4
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] However, in the process of FAD application, only the J-integral value in the critical state can be obtained. How to calculate the elastic-plastic J-integral at the evaluation point inside the FAD and how to consider the influence of material performance degradation on the J-integral calculation value are technical difficulties.

Method used

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  • Leak before burst analysis method based on failure assessment diagram
  • Leak before burst analysis method based on failure assessment diagram
  • Leak before burst analysis method based on failure assessment diagram

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Embodiment 1

[0089] The pipe outer diameter R of the straight pipe section of an austenitic stainless steel casting o =814.5mm, pipe wall thickness t=72.5mm. The analysis process of LBB under certain working conditions is given here. Under this working condition, the main pipeline of the primary circuit has been in service for 40 years.

[0090] (1) Service status analysis

[0091] When the main pipeline of the primary circuit has been in service for 40 years, the elastic modulus E of the material is 180GPa, and the Poisson's ratio ν is 0.3.

[0092] (2) Initial crack selection

[0093] Such as figure 2 As shown, select a circumferential crack that initially penetrates the wall thickness, and the circumferential angle 2θ of the crack is 45 o (Crack length a=2θR o )

[0094] (3) Load analysis

[0095] Obtain the load information at room temperature at a certain moment in the working condition, and divide various loads into primary stress loads and secondary stress loads according t...

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Abstract

The present invention relates to a leak before burst (LBB) analysis method based on a failure assessment diagram (FAD). The method comprises the following steps: (a) service state analysis; (b) initial crack selection; (c) load analysis; (d) line elastic stress intensity factor (SIF) calculation; (e) ultimate load analysis; (f) evaluation point coordinate calculation; (g) FAD selection; (h) evaluation point drawing; (i) elastoplastic SIF calculation; (j) J-integral calculation; (k) calculation and fitting of the J-integral of different cracks; (l) calculation of the structural failure criticalcrack size; (m) calculation of the structural critical leakage crack size; and (n) LBB criterion evaluation. According to the method provided by the present invention, based on the FAD theory, defects that the theoretical basis of elastoplastic analysis in the existing norms is insufficient, the existing J-integral calculation manual has a limited application scope, the finite element modeling analysis process is complicated, and the processes for calculating the structural failure critical crack size and the structural critical leakage crack size are complicated, and the like are overcome, and a FAD-based LBB analysis basis is provided.

Description

technical field [0001] The invention belongs to the technical field of structural integrity evaluation of austenitic stainless steel castings of primary circuit main pipes in pressurized water reactor nuclear power plants, and specifically relates to an analysis method for primary circuit main pipes leaking before explosion based on failure assessment diagrams, which is a safety assessment for nuclear power key equipment Provide accurate technical basis. Background technique [0002] Austenitic stainless steel castings (CASS) are generally used for the main pipeline of the PWR primary circuit. A certain amount of ferrite will be introduced during the material casting process. After long-term service at the PWR operating temperature (292-328°C), the ferrite Phase decomposition occurs and the toughness of the material decreases. Studies have shown that the impact toughness of CASS before and after aging can decrease by more than 70%. At the same time, defects (such as cracks...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/50
CPCG06F2119/04G06F30/23
Inventor 陈明亚余伟炜安英辉薛飞陈志林王春晖郁杨天李平仁师金华黄平王俊钱桂安
Owner SUZHOU NUCLEAR POWER RES INST
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