bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of Piping Components for High Temperature
Authors: Adibi-Asl Reza 
Published: November 2022

Abstract
ASME Section III Div. 5 provides design rules for high temperature applications involving deformations in the creep range. The latest Code edition is mainly focused on component design and guidelines for piping analysis and design is very limited. For piping analysis, the Code refers to ASME Section III Div. 1 NB-3600 rules along with specific requirements within Div. 5 design by analysis requirement. This paper reviews these requirements and further explores how these requirements can be utilized in piping analysis.
Study on Ductile Crack Extension and Fracture Behavior in Plate Specimen With a Semi-Elliptical Surface Crack Using a BWR Reactor Pressure Vessel Material
Authors: Hayashi Takahiro , Ogawa Takuya , Yoshida Shuichi , Itatani Masao , Saito Toshiyuki 
Published: November 2022

Abstract
Cases of stress corrosion cracking (SCC) in Ni-base alloy weld metals welded to the low alloy steel (LAS) in reactor pressure vessel (RPV) components have led to discussions on the possibility of SCC propagating into the RPV. In the previous study, the fracture mode of dissimilar metal welds (DMWs) of LAS and Ni-base alloy weld has been investigated by using a large-scale, heavy forged steel part named “bottom head ring” of the RPV, manufactured for a recent boiling water reactor (BWR). The fracture loads evaluated using the elastic-plastic fracture mechanics (EPFM) methodology have showed fairly good agreement with the maximum loads in the fracture tests on plate specimens with a semi-elliptical surface crack. All the fracture tests have successfully demonstrated the applicability of the fracture assessment methodology based on EPFM to the DMWs of RPV components.
In the fracture tests on the plate specimens, a periodic unloading condition was applied in order to obtain specimen compliance: inverse of the gradient in the load-displacement relationship under unloading. The compliances were evaluated from the crack mouth opening displacement (CMOD) data that have been obtained for large CMOD of more than 10 mm at fracture. The results of detailed evaluations of the ductile crack extension behavior based on the evaluated compliance indicated that the ductile crack extension occurred near the maximum load. Evaluations of the J–Δa relationships of the plate specimens based on the CMOD data were also performed by finite element analyses (FEA) according to the proposed method. The J–R curves obtained for the plate specimens commonly showed similar behaviors of having significantly higher J for the small Δa range from 0 to about 2 mm than that for the compact tension (C(T)) specimen, indicating a difference in the plastic constraint in the crack tip between the two types of specimens. These results demonstrate that the method proposed in this study is highly useful for evaluating the J–Δa relationship of the fracture test specimen. Fracture assessments using the J–R curves of the plate specimens provided a better prediction of the fracture load than that using the J–R curve of the conventional C(T) specimen. All the results supported the applicability of the EPFM methodology in the fracture evaluation, shown in the previous work.
Damage Evaluations for BWR Lower Head in Severe Accident Based on Multi-Physics Simulations
Authors: Katsuyama Jinya , Yamaguchi Yoshihito , Nemoto Yoshiyuki , Furuta Takuya , Kaji Yoshiyuki 
Published: November 2022

Abstract
To assess rupture behavior of the lower head of reactor pressure vessel in boiling-water-type nuclear power plants due to severe accident like Fukushima Daiichi, we have been developing an analysis method based on coupled analysis of three-dimensional multi-physics simulations composed of radiation transport, thermal-hydraulics (TH) and thermal-elastic-plastic-creep analyses. In this simulation, Monte Carlo radiation transport calculation is firstly performed by using PHITS code to compute proton dose distribution considering molten conditions of core materials. Then the deposit energies at each location is imported into TH analysis code ANSYS Fluent with the same geometry and temperature distribution is simulated by thermal-fluid dynamics. Finally, temperature distribution obtained from TH analysis is applied to thermal-elastic-plastic-creep analyses using FINAS-STAR and then damage evaluation is carried out based on several criterions such as Kachanov, Larson-Miller-parameter, melting point. To conduct such analyses, we also have continued to obtain experimental data on creep deformation in high temperature range. In this study, to predict time and location of reactor pressure vessel (RPV) lower head rupture of boiling water reactors (BWRs) considering creep damage mechanisms, we performed creep damage evaluations based on developing analysis method by using detailed three-dimensional model of RPV lower head with control rod guide tubes, stub tubes and welds. From the detailed analysis results, it was concluded that failure regions of BWR lower head are only the control rod guide tubes or stub tubes under simulated conditions.
Environment Assisted Fatigue – Rules, Assumptions and Challenges for Fatigue Management of Primary Piping
Authors: Solin Jussi , Seppänen Tommi , Lemettinen Petri , Vanninen Rami , Pulkkinen Erkki 
Published: November 2022

Abstract
This paper introduces and discusses the commonly used methods for calculating environmental penalty factors (Fen) to be used in fatigue assessment of stainless reactor components.
Three alternative methods for determining Fen factors are introduced and instructed in the JSME S NF1-2009 Code in a language providing a designer the guidance needed for reliable and repeatable EAF assessment. Following these instructions together with the equations and parameters given in the NUREG/CR-6909 it is possible to obtain same Fen factors as by careful reading of the NUREG/CR-6909 alone.
The NUREG/CR-6909, Rev. 1 contains notable amounts of valuable information, but instructions for application can be ambiguous or conflicting. An example related to the modified strain rate approach for determining Fen factors is provided.
Research and Development of Viscous Fluid Dampers for Improvement of Seismic Resistance of Thermal Power Plants: Part 12 Vibration Measurement of Existing Boiler Structure
Authors: Minagawa Keisuke , Aida Kiyoshi , Fujita Satoshi 
Published: November 2022

Abstract
Thermal power generation is a very important power source until renewable energy or carbon-free energy become widespread.
Japan is one of the most earthquake-prone countries in the world, and coal-fired power plants have been damaged by major earthquakes. For example, strong earthquakes such as the Great East Japan Earthquake in 2011, the Hokkaido Eastern Iburi Earthquake in 2018 and the earthquake off the coast of Fukushima in 2021 caused coal-fired power plants to shut down for long periods of time, and these had a significant impact on society. Therefore, it is important to improve the seismic safety of existing coal-fired power plants in earthquake-prone countries such as Japan.
The authors have proposed an application of visco-elastic dampers to a boiler structure in a coal-fired power plant to improve seismic performance. In our past papers, development of the damper, manufacturing and various experimental tests of prototypes were carried out, then the application of the damper was effective to reduce the base shear force of a support structure of the boiler, and the dampers had a long lifetime for continuous deformation.
In order to effectively apply these dampers to a boiler structure, it is important to construct an analysis model of the boiler structure for suitable distribution of dampers. Thus observations of actual seismic response of the boiler structure to build an accurate analysis model are required. Therefore, this paper deals with a long-term vibration measurement of seismic response of an actual coal-fired thermal power plant in Japan. The long-term vibration measurement will also effective for early detections of damage due to aging or earthquakes. A system of the vibration measurement and an example of the measurement results will be reported in this paper.
Development of C-Ring Geometry to Explore Fatigue Crack Extension and Verification in High-Pressure Vessels
Authors: Wheeler Robert W. , Ronevich Joseph , San Marchi Chris , Grimmer Peter , Emery John M. 
Published: November 2022

Abstract
High pressure hydrogen storage vessels are frequently retired upon reaching their designed number of pressure cycles, even in cases where the in-use pressure cycles are significantly less severe than the design pressure cycle. One method for extending the life of hydrogen vessels is recertification through non-destructive evaluation (NDE); however, NDE techniques are frequently evaluated with machined defects in test samples rather than fatigue cracks which occur during pressure cycling and may be more difficult to detect. In this paper, 50 mm wide ring sections (called C-rings, since they represent slightly more than half the circumference) were extracted from pressure vessels and mechanically cycled to establish fatigue cracks. Sub-millimeter starter notches were machined, via plunge electrical discharge machining (EDM), to control the location of crack initiation. Crack growth was monitored via direct current potential difference (DCPD) and backface strain gauges, both of which were shown to be good indicators for crack propagation. The C-ring geometry and fatigue crack growth were modeled to demonstrate the ability to monitor/control the crack length and area, which can be used to develop calibration samples of varying crack depth for NDE techniques. Additionally, this sample is intended to evaluate the influence of residual stresses on the sensitivity of NDE techniques, such as the design stresses in autofrettaged vessels.
A Methodology for Calculating the Minimum Pressurization Temperature of New Built Hydroprocessing Reactors in 2¼Cr-1Mo-¼V Low Alloy Steel
Authors: Rensman Jan-Willem , Frittitta Davide , Fusari Fausto , Ronchi Nicola 
Published: November 2022

Abstract
Minimum Pressurization Temperature (MPT) is the lowest temperature at which a hydroprocessing reactor can start pressurizing safely. A reliable MPT evaluation is necessary due to the susceptibility of hydroprocessing reactor materials to the combined effects of temper embrittlement and hydrogen embrittlement. Accurate estimation of the MPT is important for owners, who are looking for the lowest MPT values to reduce start-up time.
Several methods to develop an MPT have been adopted in the past mainly based upon experimental data and/or acquired from material exposed in reactors over time. Most of these methods are based on historical concepts of hydrogen embrittlement in conventional 2¼Cr-1Mo alloys. For 2¼Cr-1Mo-¼V low alloy steels, hydrogen diffusion and trapping capacity are different and thus, potential for internal cracking is different. In addition, experiments to assess the influence of external hydrogen environment on stable cracking have been reported and provide more insight into stable crack growth potential due to a hydrogen atmosphere.
The traditional methods could lead to an overly conservative approach. The result could lead to an over-estimation (i.e., a shift to higher temperature envelope) of the MPT curve.
In this paper the authors describe a methodology for deriving the MPT for new built 2¼Cr-1Mo-¼V low alloy steel reactors. It is based on API TR-934 F parts 3 and 4 [1],[2] combined with some practices from WRC Bulletin 562 [3]. A case study will be described and a comparison with results according to historical calculations will be presented.
A Novel Real-Time Evaluation Method for the Temperature Field in the Electrofusion Welding of Polyethylene Pipe
Authors: Guo Weican , Tao Yangji , Miao Cunjian 
Published: November 2022

Abstract
In the electrofusion (EF) welding process of polyethylene (PE) pipes, the welding temperature field and its variations are available for predicting EF joint properties. The welding temperature field has key factors, which determine the welding quality to influence EF joint properties. However, it is difficult to measure and evaluate the welding temperature field in real time. We proposed a novel real-time evaluation method for the temperature field in the EF welding process of PE pipes. The temperature field in the EF welding process was simulated, based on a one-dimensional unsteady state heat transfer model. In the simulation, the temperature of the fusion zone dropped at the same rate. The EF joints of the whole welding process were detected by the ultrasonic phased array inspection, and phased array images were recorded in real time by using the video recording function of ultrasonic inspection instruments. According to the rate of temperature dropping in the fusion zone, the measurement model of the welding temperature field was established with video recordings. Then, welding temperature fields were evaluated in real time by using the temperature field of the normal welding process. Furthermore, the evaluation method was to set the foundation for exploring the formative mechanism of EF joint strength and optimizing welding parameters.
Artificial Intelligence for the Output Processing of Phased-Array Ultrasonic Test Applied to Materials Defects Detection in the ITER Vacuum Vessel Welding Operations
Authors: Ortiz de Zuniga Maria , Prinja Nawal , Casanova Cristian , Dans Alvarez de Sotomayor Andres , Febvre Max , Camacho Lopez Ana Maria , Rodríguez Prieto Alvaro 
Published: November 2022

Abstract
Artificial Intelligence (AI) has been applied to accelerate the analysis of outputs from the phased-array ultrasonic (PAUT) non-destructive testing (NDT).
The aim of this work is the development and analysis of AI tools for the output processing of PAUT applied to welding defects detection in the ITER Vacuum Vessel manufacturing. The development of the AI model, parameters of the data and data processing are described herein.
This development shows that AI is an appropriate tool to process PAUT data, resulting in an accuracy of prediction of over 83%. This allows for prompter data availability and gives an additional information set in order for projects to take informed decisions. The human error factors are decreased through this automation, as is the large time required to process each PAUT output, which can be decreased from an average of a week to a matter of minutes. A successful AI application for UT has a potential to save time and cost.
Mechanism of High Temperature Stability on Microstructures of 25Cr35NiNb Alloy Prepared by Laser Additive Manufacturing
Authors: Li Jizhan , Fan Zhichao , Chen Tao , Zhou Yu 
Published: November 2022

Abstract
The performance of static casting 25Cr35NiNb alloy pipe fittings with complex shapes for ethylene cracking furnace is insufficient, which affects the safe operation of equipment, and becomes an urgent problem to be solved in this field. Laser additive manufacturing (LAM) technique is suitable for the fabrication of complex components with high performance. 25Cr35NiNb alloy prepared by LAM is different from that prepared by static casting or centrifugal casting due to the solidification with the cooling rate of 102∼105 K/s in a tiny molten pool. In order to fabricate complex pipe fittings by LAM, the performance of 25Cr35NiNb alloy prepared by LAM needs to be clarified and the mechanism also needs to be revealed.
This paper focuses on the mechanism of high temperature stability on microstructures of 25Cr35NiNb alloy prepared by LAM. Firstly, two kinds of 25Cr35NiNb alloy deposits were prepared by LAM with different processing parameters. Secondly, heat treatments were executed in the temperature range from 850°C to 1275°C for 25Cr35NiNb alloy deposits. Then, the microstructures of 25Cr35NiNb alloy were observed by optical microscope (OM) and scanning electron microscopy (SEM). It is found that the finer the microstructures of the original deposits was, the better the high temperature stability of microstructures was. The results of electron probe microanalysis (EPMA) show that the distribution of Nb and Ti elements in the original deposits affects the high temperature stability of microstructures. The finer microstructure has the more uniform distribution of Nb and Ti elements, which improves the high temperature microstructural stability.
Investigations on the Failure Behavior of Specimens Containing Crack Fields Made by Additive Manufacturing
Authors: Stumpfrock Ludwig , Weber Ulrich , Weihe Stefan , Seidenfuss Michael , Mally Linda 
Published: November 2022

Abstract
Laminar and quasi-laminar orientations of hydrogen flakes with an inclination up to 16° to the pressure retaining surface were found in pressure vessels of Belgian nuclear power plants. Because of their orientation, these crack tips undergo predominantly mixed-mode loading conditions under internal pressure and the induced stress and strain fields of the single crack tips influence each other.
In a former paper, the failure behavior under mixed-mode loading conditions was investigated at RT (Room Temperature) in the upper shelf and in the lower transition region of the steel 22NiMoCr3-7, respectively. In this paper, the failure behavior will be shown for many different levels of material toughness (beginning from upper shelf down to the lower shelf region) on experiments.
Additionally numerical simulations are carried out with extended micromechanical based damage mechanics models. For the description of ductile failure mode the Rousselier model is used and the Beremin model to calculate the probability of cleavage fracture. To simulate the sensitivity for low stress triaxiality damage by shear loading, the damage mechanics model was enhanced with a term to account for damage evolution by shear. For numerical simulations in the transition region of brittle-to-ductile failure a coupled damage mechanics model (enhanced Rousselier & Beremin) will be used. In this paper, the current state of the ongoing research project is presented.
Optimization Design of Focusing Electromagnetic Acoustic Transducer for Crack Detection of Pressure Structure
Authors: Wang Zhe , Fan Zhichao , Su Yuanlian , Cheng Jingwei , Wang Haibin , Bu Yangguang 
Published: November 2022

Abstract
High-precision detection of crack is of great significance to ensure the safety of pressure equipment in service. Electromagnetic ultrasound has the advantages of no coupling agent, no surface pretreatment, and non-contact. However, several problems such as low energy conversion efficiency and poor sound field directivity limit the application in crack detection. This paper designs a multi-layer line-focusing electromagnetic acoustic bulk wave transducer (MLF-EMAT). A simulation model containing MLF-EMAT is established based on the Lorentz force and magnetostrictive force transduction mechanism. The influence of some transducer parameters (wire width, wire thickness, coil turns, lift-off distance) on the echo response of crack has been studied. The orthogonal experimental design method is used to optimize the controllable parameters of the transducer. When the width of the permanent magnet is equivalent to the width of the coil, the larger the number of coil layers, the larger the amplitude of the echo response of crack. An experimental platform for electromagnetic ultrasonic testing is established, and several line-focusing electromagnetic acoustic transducers with multiple parameters are prepared. The comparison results show that the optimized MLF-EMAT significantly improves the signal-to-noise ratio of echo response of crack. The amplitude of echo wave is increased by about 78% compared with that before optimization, and the detection accuracy of crack notch depth is up to 0.05 mm. The MLF-EMAT proposed in this study lays the foundation for the application of crack detection or monitoring of pressure vessels and pipes under complex working conditions.
Investigation of Surface Finish Effect on Fatigue Strength of Carbon and Low Alloy Steels
Authors: Asada Seiji , Hirano Akihiko , Wang Yun , Itatani Masao , Takanashi Masahiro , Nomura Yuichiro , Ochi Fumihiro , Ogawa Takeshi 
Published: November 2022

Abstract
The subcommittees on Design Fatigue Curve (DFC) and Design Fatigue Curve 2 (DFC2) in Atomic Energy Research Committee of the Japan Welding Engineering Society (JWES) developed a new fatigue analysis method. A design fatigue curve by this method is established by applying factors on stress and cycles, which have been derived by statistical analysis, to the best-fit curve using tensile strength as a variable considering the mean stress correction called the Smith-Watson-Topper approach. For high cycle region, the variable amplitude effect of EN 13445 is employed.
This fatigue analysis method was brought to the JSME Code Committee, and the JSME reviewed this method, and decided to incorporate it into the JSME Environmental Fatigue Evaluation Method with some modifications including the fatigue strength reduction factor for surface finish effect. This paper addresses surface finish effect on fatigue strength of carbon and low alloy steels.
To perform further investigation for surface finish effect on fatigue strength of carbon and low alloy steels, the DFC3 Subcommittee was established with the support of a Japanese utility project. A series of fatigue tests for surface finish effect was performed for carbon and low alloy steels in the utility project, and the fatigue test data were evaluated by the DFC3 Subcommittee. In this paper, the series of fatigue tests are introduced and discussed. Finally, the validity for the fatigue strength reduction factor for surface finish effect developed by the JSME Committee has been confirmed based on the above fatigue tests.
Study on Leakage Monitoring Method of Supercritical CO2 Long-Distance Pipeline
Authors: Guo Xiaolu , Fan Zhichao , Xu Shuangqing 
Published: November 2022

Abstract
The carbon capture, transportation and storage technology is an important option to achieve carbon peak and carbon neutralization. In order to prevent the pipeline fracture propagation, human injury and medium loss during the longdistance CO2 pipeline leakage, it is necessary to establish the on-line leakage monitoring technology. At present, there is not enough understanding of the law of pressure response and phase change during the leakage of CO2 pipeline, and there is still a lack of accurate leakage monitoring method based on the propagation law of decompression wave. Based on the release experiment data in the industrial scale pipeline, combined with the theoretical analysis, the pressure drop-rebound mechanism as a result of wave propagation at the moment of rupture was studied. The attenuation law of decompression wave strength will be researched for the establishment of the monitoring method of pipeline leakage position and orifice diameter. The reliability of the monitoring method considering the effect of flow state on the leakage characteristics of CO2 pipelines was studied and a modified algorithm for higher measurement accuracy was proposed. This study was of great significance to the stability and safe operation of CO2 long-distance pipeline system.