Fatigue Life Assessment of Reactor Coolant System Components by Using Transfer Functions of Integrated Fe Model

Choi, Suk‐Joo; Chang, Yoon‐Suk; Choi, Jae-Boong; Kim, Young‐Jin; Jhung, Myung Jo; Choi, Young−Hwan

doi:10.5516/net.2010.42.5.590

Cited by 8 publications

(2 citation statements)

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“…[4] proposed the thermal stresses calculation method using transfer matrices and Green's function in order to calculate the thermal stresses rapidly. According to this method, so-called Green's function approach, the thermal stresses at an arbitrary location can be defined as follow: (1) where G(t) is a Green's function for the thermal stresses at arbitrary location and φ(t) is the coolant temperature for a transient operation.…”

Section: Theory Of Green's Function Approach and New Algorithmmentioning

confidence: 99%

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Modified Green’s Function Approach Using Temperature-Dependent Material Properties and Stress Properties for Thermal Fatigue Analysis

Jhung

Choi

2012

AMM

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Fatigue damage caused by alternating operational stresses in terms of temperature or pressure change is the one of important damage mechanisms in the nuclear power plants (NPPs). Although components important to safety were designed to withstand the fatigue damage, cumulative usage factor (CUF) at some locations can exceed the design limit beyond the design life. So, it is important to monitor the fatigue damage of major components during the long term operation. To evaluate fatigue damage, the Green’s function approach has been generally used. In this approach, thermal stresses can be directly calculated from the convolution integration on the coolant temperature history and Green’s function. And, Green’s function is defined as a stress variation at the arbitrary point when the coolant temperature is increased as a unit step. However, this approach cannot be applied to the fatigue analysis using temperature-dependent material properties because it is assumed that the system is linear. In this paper, the modified Green’s function approach considering temperature-dependent material properties is proposed by using neural network. To verify the modified Green’s function method, thermal stresses by the proposed method are compared with those by finite element analysis (FEA) at the transition wall of reactor pressure vessel and the analysis results between two methods are well agreed. Finally, it is anticipated that more precise fatigue evaluation is performed by using the proposed method.

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Section: Theory Of Green's Function Approach and New Algorithmmentioning

confidence: 99%

“…And in Germany, Siemens-KWU develops the Fatigue Monitoring System (FAMOS) and it was applied to the German reactors. In Korea, the NuFMS was developed by KHNP in 2011 and it will be applied to the Korea reactors [1]. Most of FMS have used Green's function approach (GFA) to calculate the thermal stresses rapidly.…”

Section: Introductionmentioning

confidence: 99%