Comparison of Environmental Fatigue Evaluation Methods in LWR Water

2008 ◽  
Author(s):  
Makoto Higuchi
Keyword(s):  
Research Council ◽  
Evaluation Method ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Evaluation Methods ◽  
Fatigue Tests ◽  
Final Report ◽  
The Us ◽  
Fatigue Data ◽  
Fatigue Evaluation

Many studies on the environmental fatigue of structural materials in LWR (Light Water Reactor) water have been carried out over the past 30 years. Early environmental fatigue tests were mainly carried out in Japan in the 1980s, and these results were reported to the ASME in 1988. After that, O. Chopra and W. Shack of ANL (Argonne National Laboratory) also carried out similar fatigue tests and reported that their data corresponded well to Japanese data. In the US, the PVRC (Pressure Vessel Research Council) started the CLEE Committee (Cyclic Life and Environmental Effect, Chair: Sumio Yukawa) for developing the environmental fatigue evaluation method in LWR water under the request from the ASME in 1991. This committee continued for 13 years and closed in 2004 after publishing the final report as WRC (Welding Research Council) Bulletin 487. After 1990 in Japan, the EFD Project (1993–1995) and the EFT Project (1994–2006) were carried out under the collaboration of electric utilities, plant vendors and government. A large number of environmental fatigue data have been generated in these projects, and these were offered to the US through the CLEE Committee. Based on Japanese and US fatigue data, environmental fatigue evaluation methods have been established in both countries that assess the effects of some parameters on fatigue life reduction in LWR water environments. This paper introduces the history of studies on the environmental fatigue in LWR water and the contributions of Sumio Yukawa to these activities. After that, the comparison of three major methods of environmental fatigue evaluation such as PVRC, JSME and MJREG/CR-6909 are reported.

Development of New Design Fatigue Curves in Japan: Proposal of a New Fatigue Evaluation Method

2018 ◽  
Author(s):  
Seiji Asada ◽  
Akihiko Hirano ◽  
Toshiyuki Saito ◽  
Yasukazu Takada ◽  
Hideo Kobayashi
Keyword(s):  
Stainless Steels ◽  
Evaluation Method ◽  
Austenitic Stainless Steels ◽  
Fatigue Tests ◽  
Carbon Steels ◽  
Low Alloy Steels ◽  
Stress Effect ◽  
Fatigue Data ◽  
Alloy Steels ◽  
Fatigue Evaluation

In order to develop new design fatigue curves for carbon steels & low-alloy steels and austenitic stainless steels and a new design fatigue evaluation method that are rational and have clear design basis, Design Fatigue Curve (DFC) Phase 1 subcommittee and Phase 2 subcommittee were established in the Atomic Energy Research Committee in the Japan Welding Engineering Society (JWES). The study on design fatigue curves was actively performed in the subcommittees. In the subcommittees, domestic and foreign fatigue data of small test specimens in air were collected and a comprehensive fatigue database (≈6000 data) was constructed and the accurate best-fit curves of carbon steels & low-alloy steels and austenitic stainless steels were developed. Design factors were investigated. Also, a Japanese utility collaborative project performed large scale fatigue tests using austenitic stainless steel piping and low-alloy steel flat plates as well as fatigue tests using small specimens to obtain not only basic data but also fatigue data of mean stress effect, surface finish effect and size effect. Those test results were provided to the subcommittee and utilized the above studies. Based on the above studies, a new fatigue evaluation method has been developed.

Codes, Standards, Rules and Assumptions on Environment Assisted Fatigue for Fatigue Management of Primary Piping

2020 ◽  
Author(s):  
Jussi Solin ◽  
Tommi Seppänen ◽  
Rami Vanninen ◽  
Erkki Pulkkinen ◽  
Petri Lemettinen ◽  
...  
Keyword(s):  
National Laboratory ◽  
Argonne National Laboratory ◽  
Current Status ◽  
Basic Material ◽  
Primary Circuit ◽  
Final Report ◽  
Regulatory Requirement ◽  
Cyclic Operation ◽  
The Us ◽  
Code Language

Abstract All international codes used for design, operation and inspection of NPP primary circuit pressure boundaries are rooted to the ASME Boiler and Pressure Vessel Code, Section III, Nuclear Vessels, 1963. Article 4, N-415 “Analysis for cyclic operation” instructed calculation of stress intensities for fatigue transients and provided two design curves for basic material types. Different codes such as ASME, RCC-M, KTA, PNAE and JSME have much in common, but partial deviations exist. In 2007 the US NRC Regulatory Guide 1.207 endorsed a methodology for accounting the environmental effects. It was mainly based on extensive work in Japan and the Argonne National Laboratory. The final report of ANL, NUREG/CR-6909 became a major reference and subject of criticism. However, the first approach for environment assisted fatigue (EAF) written in ‘code language’ was published in Japan and a regulatory requirement for consideration of EAF both for operating reactors and new designs appeared first in Finland. This paper discusses challenges in management of fatigue and the evolving state-of-the-art in different codes, standards, rules and assumptions. The roots and current status of fatigue curves and design criteria applied in Finnish NPP’s are explained.

Structural and Thermochemical Analysis of Nano-Boric Acid

2015 ◽  
Vol 1086 ◽  
pp. 128-131
Author(s):  
Sam Linu ◽  
K. Suba ◽  
Radhakrishnan Amrutha
Keyword(s):  
Boric Acid ◽  
Structural Parameters ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Percent Reduction ◽  
Natural Structure ◽  
Increase Energy Efficiency ◽  
Thermal Chemistry ◽  
The Us ◽  
Motor Oils

Scientists at the US Department of Energys Argonne National Laboratory have begun to combine nanoparticles of boric acidknown primarily as a mild antiseptic and eye cleanserwith traditional motor oils in order to improve their lubricity and by doing so increase energy efficiency. In laboratory tests, these new boric acid suspensions have reduced by as much as two-thirds the energy lost through friction as heat. This could result in a four or five percent reduction in fuel consumption. Reducing the size of the particles solved a number of old problems and opened up a number of new possibilities. Boric acid owes its lubricious properties to its unique natural structure. The compound consists of a stack of crystallized layers in which the atoms tightly adhere to each other. However, these layers stack themselves relatively far apart, so that the intermolecular bonds (van der Waals forces) are comparatively weak. When stressed, the compounds layers smear and slide over one another easily, like a strewn deck of playing cards. The strong bonding within each layer prevents direct contact between sliding parts, lowering friction and minimizing wear. In our presentation it is proposed to carry out computational studies on boric acid. Their structural parameters, thermal chemistry, SCF energy and electronic structure would be presented.

Thermal Fatigue Evaluation Model of a Microelectronic Chip in Terms of Interfacial Singularity

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Xiaoguang Huang ◽  
Zhiqiang Wang
Keyword(s):  
Thermal Fatigue ◽  
Evaluation Method ◽  
Evaluation Model ◽  
Thermomechanical Properties ◽  
Fatigue Tests ◽  
Strain Intensity ◽  
Intensity Factors ◽  
Singular Stress ◽  
Stress Strain ◽  
Fatigue Evaluation

Abstract Thermal fatigue failure of microelectronic chip often initiates from the interface between solder and substrate, and the service life of the chip is largely dependent on the singular stress–strain at this interface. To provide a reasonable life evaluation method, three thermal fatigue evaluation models, including strain-based and stress–strain based, have been established in terms of the interfacial singular fields. Thermal fatigue lives of different chips under different thermal cycles are obtained by thermal fatigue tests, and the stress and strain intensity factors and singular orders at the solder/substrate interface are computed at the same conditions, to determine the material constants in the established models. The thermal fatigue lives predicted are in acceptable agreement with the experimental results. What is more, the application of these thermal fatigue models demonstrates a fact that the thermal fatigue of the microelectronic chips can be evaluated uniformly no matter what the shapes, dimensions of the chip, and the thermomechanical properties of the solders are, as long as the relevant stress–strain intensity factors and singular orders are obtained.

Updated Knowledge Implemented to the Revision of Environmental Fatigue Evaluation Method for Nuclear Power Plant in JSME Code

2009 ◽  
Author(s):  
Makoto Higuchi ◽  
Takao Nakamura ◽  
Yasuaki Sugie
Keyword(s):  
Power Generation ◽  
Fatigue Life ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Evaluation Method ◽  
Power Engineering ◽  
Nuclear Power Generation ◽  
Fatigue Data ◽  
Fatigue Evaluation

Many examinations concerning the fatigue life reduction for structural materials of nuclear power plants in water simulated LWR coolants had been carried out after the first paper had been recognized in Japan [1, 2]. Based on these results, the method to evaluate the fatigue damage for the materials exposed to the LWR coolant had been developed. After 1990s in Japan, the Environmental Fatigue Data Committee (EFD) of the Thermal and Nuclear Power Engineering Society (TENPES), the Project on Environmental Fatigue Testing (EFT) supported by the Japan Power Engineering and Inspection Corporation (JAPEIC) and the Japan Nuclear Energy Safety Organization (JNES) and some utility joint studies have investigated the environmental fatigue. In September 2000, the Nuclear Power Generation Safety Management Division of the Agency for Natural Resources and Energy, Ministry of International Trade and Industry issued “Guidelines for Evaluating Fatigue Initiation Life Reduction in the LWR Environment” (hereafter, called “the MITI Guidelines”) [3]. These guidelines include an equation to evaluate environmental fatigue and require electric utilities to consider the environmental effects in their Plant Life Management (PLM) activities. However, the MITI Guidelines do not provide specific and practical techniques for evaluating environmental fatigue under actual plant conditions. Accordingly, TENPES took on the task to produce one. In 2002 TENPES issued the “Guidelines on Environmental Fatigue Evaluation for LWR Component” [4, 5] (hereafter, called “the TENPES Guidelines”) based on the techniques developed by the EFD Committee. A set of Rules, called the Environmental Fatigue Evaluation Method (EFEM), was established in the Codes for Nuclear Power Generation Facilities - Environmental Fatigue Evaluation Method for Nuclear Power Plants (JSME S NF1-2006, EFEM-2006)[6], which was issued in March 2006 by reviewing the equations for the environmental fatigue life correction factor, Fen, specified in the MITI Guidelines, and the techniques for evaluating environmental fatigue specified in the TENPES Guidelines, and considering the new environmental fatigue data including JNES-SS report (August 2005) [7]. The EFEM revised version has been drafted by incorporating the updated knowledge described in JNES-SS report (April 2007) [8] and is scheduled to be issued by the end of 2009. This paper introduces the revision in it and their technical basis. Additionally, future issues are addressed to be considered in the improvement of the EFEM.

Sign in / Sign up

Export Citation Format

Share Document