Session: MF-06-02 Materials and Technologies for Nuclear Power Plants II

Paper Number: 61922

Start Time: Tuesday, July 13, 2021, 08:00 PM

61922 - Creep and Creep Rupture Behaviors of Alloy 690 Steam Generator Tubes at High Temperature – Experiments and Larson-Miller Parameters (Lmp) 

Failure behavior of internally pressurized flawed and unflawed steam generator tubes (SGs) is one of the concern in the research field of severe accident of nuclear power plant (NPP). In recent years, Alloy 690 which has increased the Cr content has been replaced for the SG tubes due to its high corrosion resistance against stress corrosion cracking (SCC). However, there is lack of research on the creep strength and creep rupture behavior of SG tubes made by Alloy 690 material for prediction of failure probability of SG tubes. In this study, creep test and creep rupture test were performed to estimate creep life of Alloy 690 SG tubes. Based on the test results, Larson-Miller parameter was determined by using bi-linear fitting at both  low and high stress levels, and creep rupture behavior under designed conditions (temperature and pressure) was compared with predicted results by flow stress model and creep rupture model. According to the experimental results, the relationship between applied stress and LMP was fitted for entire creep data. An optimum material specific constant, C1-C3, in the master curve was investigated to be C1=-3973.7, C2=48627.9 and C3=11.26339 which were calculated in units of Kelvin (Temperature), Pa (Stress), and second (tr).

Presenting Author: Jongmin Kim Korea Atomic Energy Research Institute

Authors:

Jongmin Kim Korea Atomic Energy Research Institute
Woogon Kim Korea Atomic Energy Research Institute
Minchul Kim Korea Atomic Energy Research Institute