Development of failure evaluation method for BWR Lower head in severe accident; high temperature creep test and creep damage model

The use of salt rock for underground radioactive waste disposal facilities requires a comprehensive analysis of the creep-damage process in salt rock. A computer-controlled creep setup was employed to carry out a creep test of salt rock that lasted as long as 359 days under a constant uniaxial stress. The acoustic emission (AE) space-time evolution and energy-releasing characteristics during the creep test were studied in the meantime. A new creep-damage model is proposed on the basis of a fractional derivative by combining the AE statistical regularity. It indicates that the AE data in the non-decay creep process of salt rock can be divided into three stages. Furthermore, the authors propose a new creep-damage model of salt rock based on a fractional derivative. The parameters in the model were determined by the Quasi-Newton method. The fitting analysis suggests that the new creep-damage model provides a precise description of full creep regions in salt rock.

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Evaluation of Creep Properties of Alloy 690 Steam Generator Tubes at High Temperature Using Tube Specimen

Volume 6B: Materials and Fabrication ◽

10.1115/pvp2019-93498 ◽

2019 ◽

Author(s):

Jongmin Kim ◽

Woogon Kim ◽

Minchul Kim

Keyword(s):

High Temperature ◽

Steam Generator ◽

Creep Test ◽

Rupture Life ◽

Creep Rupture ◽

Severe Accident ◽

High Temperature Creep ◽

Creep Life ◽

Temperature Creep ◽

Alloy 690

Abstract Thermally induced steam generator (SG) tube failures caused by hot gases from a damaged reactor core can result in a containment bypass event and may lead to release of fission products to the environment. A typical severe accident scenario is a station blackout (SBO) with loss of auxiliary feedwater. Alloy 690 which has increased the Cr content has been replaced for the SG tube due to its high corrosion resistance against stress corrosion cracking (SCC). However, there is lack of research on the high temperature creep rupture and life prediction model of Alloy 690. In this study, creep test was performed to estimate the high temperature creep rupture life of Alloy 690. Based on reported creep data and creep test results of Alloy 690 in this study, creep life extrapolation was carried out using Larson-Miller Parameter (LMP), Orr-Sherby-Dorn (OSD), Manson-Haferd Parameter (MHP), and Wilshire’s approach. And a hyperbolic sine (sinh) function to determine master curves in LMP, OSD and MHP methods was used for improving the creep life estimation of Alloy 690 material.

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The Creep-Damage Model of Salt Rock Based on Fractional Derivative

10.20944/preprints201807.0584.v1 ◽

2018 ◽

Author(s):

Hongwei Zhou ◽

Di Liu ◽

Gang Lei ◽

Dongjie Xue ◽

Yang Zhao

Keyword(s):

Fractional Derivative ◽

Creep Test ◽

Damage Model ◽

Creep Damage ◽

Uniaxial Stress ◽

Radioactive Waste Disposal ◽

Creep Process ◽

Salt Rock ◽

Damage Process ◽

Creep Damage Model

The use of salt rock for underground radioactive waste disposal facilities requires a comprehensive analysis of creep-damage process in salt rock. A computer-controlled creep setup is employed to carry out a creep test of salt rock lasted as long as 359 days under a constant uniaxial stress. The AE space-time evolution and energy releasing characteristics during creep test are studied in the meantime. A new creep-damage model is proposed on the basis of fractional derivative by combining the AE statistical regularity. It indicates that the AE data in non-decay creep process of salt rock can be divided into three stages. Furthermore, the parameters of new creep-damage model are determined by Quasi-Newton method. The fitting analysis suggests that the creep-damage model based on fractional derivative in this paper provides a precise description of full creep regions in salt rock.

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