bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spent Nuclear Fuel Mechanical Loads in the General Package Drop Scenario
Authors: Klymyshyn Nicholas , Spitz Casey , Ivanusa Pavlo , Kadooka Kevin , Fitzpatrick James 
Published: October 2021

Abstract
The US Department of Energy Spent Fuel and Waste Science and Technology program is performing research to determine the mechanical loading conditions applied to spent nuclear fuel (SNF) during normal conditions of transportation to inform mechanical tests of SNF and close an important knowledge gap related to the practical disposition of SNF in the US. A recent multi-national collaborative test campaign measured SNF assembly impact response to the 30 cm horizontal package drop scenario, which is a common regulatory basis test of SNF package design. Researchers at Pacific Northwest National Laboratory (PNNL) are using the test data to validate explicit finite element models to calculate the mechanical loads and structural response of spent nuclear fuel assemblies in the as-tested 30 cm horizontal package drop scenario. Once the as-tested package drop model is validated, the next step is to apply the model to the general 30 cm drop scenario, which includes all impact angles, all fuel assembly types, and all burnup conditions. PNNL is developing a damage model that will incorporate the results of finite element parametric studies to establish trends in SNF mechanical loading to various input parameters, like impact orientation and burnup. The damage model will have the capability to estimate mechanical loads for any single set of input parameters, but it will first be used to describe the upper bounds of potential SNF loading in the 30 cm drop scenario. This paper describes PNNL’s progress toward developing the general solution to the problem of spent nuclear fuel mechanical loads in the 30 cm package drop scenario, and it describes the next steps in closing the knowledge gap.
Prediction of Ultimate Load of Pipeline With Defects Based On Material Hardening
Authors: Fang Zhuoyu , Dong Shaohua 
Published: October 2021

Abstract
Pipelines are important facilities for the development of oil and gas, and it is of great significance to ensure their safe and efficient operation. The existing pipeline ultimate load evaluations and researches lack the consideration of pipe characteristics and failure mechanism, there are certain errors, and the types of defects involved are relatively single. In order to give full play to the potential of pipes, consider the strain hardening effect of pipeline steel during the true failure process of pipelines, and study the influence of different types of defects on the ultimate bearing capacity of the pipeline. This paper uses the twin shear stress yield criterion and based on the Ramberg-Osgood material strain hardening model to derive an equation which is used to predict the ultimate load of the defect-free X60 pipeline. Using finite element method to study different kinds of defects on the ultimate load of X60 pipeline. A model for predicting the ultimate load of the X60 pipeline with a flat-bottomed rectangular single-point external defect is fitted, and the accuracy of the model is verified by comparison with real data. The failure modes of pipelines with different defects are also studied. On the basis of the above prediction model, the ultimate load prediction models of X60 pipeline with axially adjacent double-point external defects were fitted. Besides, the critical distance of interaction between the double-point defects has been discussed. The above analysis provides a basis for the safety assessment of X60 pipeline.
Application and Limitation of Safety Valves Inspection Codes in China
Authors: Xing Jian , Han Zhiyuan , Ai Shuping 
Published: October 2021

Abstract
Safety valves are important devices to protect system by relieving pressure in oil refining and chemical equipment. According to API 576-2017 and API 510, the inspection interval for safety valves should not be more than 10 years. Also, TSG ZF001–2006 in China specifies the inspection interval for safety valves is only 1 year. However, the maintenance interval for petrochemical units normally is 3∼5 years, which thus results in the inconsistency between its inspection interval and the maintenance interval. This study firstly conducts contrastive analysis about the difference of major regulations and standards for safety valves inspection between China and API standards, and then performs thorough investigation of the operational management and regulation about the extension for safety valves inspection interval in the typical Chinese petrochemical enterprises. Besides, the failure modes and risk level of safety valves are investigated by quantitative analysis of 44,692 safety valves engineering application data in oil refining and chemical plants based on Risk-Based Inspection (RBI) technology. The result indicates that the overall risk level of safety valves is low, as the percentage of safety valves with a high-risk level is less than 1%, and the accident rate caused by safety valves failure is less than 0.005%. In addition, this study analyzes the limitations of specification such as TSG ZF001–2006 in terms of safety valves inspection and the application of regulation extension. Based on above analysis, the specifications and standards about safety valves should be revised and introduce the RBI technology to extend the inspection interval.
Study the Integrity of Flange to Gasket Connection Using ASME PCC-1 Under Bolt Tightening and Operating Condition
Authors: Kalra Balram , Kumar Arun 
Published: October 2021

Abstract
Scope of this paper is to study the flange to gasket joint under bolt tightening and operating conditions as per the guidelines specified in ASME PCC-1 Appendix O using FEA approach with ANSYS as the FEA tool. Contact pressure for various transient loading conditions is obtained and compared against the required minimum contact pressure for the leak proof joint. ASME-PCC 1 gives the guidelines for bolted flange assembly for pressure vessel and piping joints in a standardized manner. With the help of FEA tools simulation can be done and broad picture of the assembly can be looked upon so that a designer engineer can have better insights for the stress and deformation during seating and operating conditions. Thorough investigation of the flange joint has been carried out by finite element analysis in this paper and acceptance criteria as recommended in ASME PCC-1 Appendix-O have been used to establish the design in a safer and optimized way.
Pressurized Thermal Shock Analysis With Sub-Modeling
Authors: Stefanini L. , Versteylen C. , Pangukir F. S. L. , Uitslag-Doolaard H. J. , de Haan - de Wilde F. H. E. 
Published: October 2021

Abstract
In 2020, the CFD analyses have been performed on a whole reactor vessel model. The action of accumulators during the PTS transient was considered. Using these data, an attempt to the efficient use of sub-modelling is carried out in order to obtain a strong reduction in the computational costs compared to a full 3D analysis. The analyses were given a probabilistic view by using the Master Curve approach for determining the material(s) fracture toughness.
In parallel with these activities, a literature review work was carried out at NRG. The single temperature dependence of the Master Curve was incorporated into characterizations of fracture toughness for all RPV steels of interest such as SA 508 Grade 3 and Grade 4N for both forging and weld material. The literature review helps to prove that the Master Curve approach models the temperature dependence of fracture toughness for a generic pressure vessel before and after irradiation. This is because all of these steels have a BCC matrix phase lattice structure. Based on ASTM E1921, the types of microstructure falling under a BBC matrix, such as bainite, tempered bainite, tempered martensite, ferrite and pearlite, could also be evaluated using the Master Curve model. Furthermore, it is found that the chemical composition is one of parameter to look for as driving force in embrittlement RPV due to irradiation. For the very high nickel steels examined (SA508 Grade 4N), when not combined with copper and moderate manganese, irradiation is not a serious embrittling agent.
This paper describes the work performed at NRG in the years 2017–2020 in investigting the Pressurized Thermal Shock (PTS) phenomenon, summarizes the achievements and gives a general judgement of the lessons learned. Moreover, this paper aims to illustrate the scope of planned research on PTS and its role in the new NRG research program PIONIER 2021–2024. An overview of NRG’s effort to align itself with the international community is given. Particular attention is given to the probabilistic problematic related to PTS. In order to better understand this problematic and improve the current state of knowledge NRG will create a PFM tool. The tool aims to use the best practices from existing PFM software to try to answer to questions requiring attention (e.g. thermal-hydraulic uncertainty). The experience accumulated during the previous activities will be included in the tool.
Exploring Life Extension Opportunities of High-Pressure Hydrogen Pressure Vessels at Refueling Stations
Authors: Ronevich Joseph A. , San Marchi Chris , Brooks Dusty , Emery John M. , Grimmer Peter , Chant Eileen , Sims J. Robert , Belokobylka Alex , Farese Dave , Felbaum John 
Published: October 2021

Abstract
High pressure Type 2 hoop-wrapped, thick-walled vessels are commonly used at hydrogen refueling stations. Vessels installed at stations circa 2010 are now reaching their design cycle limit and are being retired, which is the motivation for exploring life extension opportunities. The number of design cycles is based on a fatigue life calculation using a fracture mechanics assessment according to ASME Section VIII, Division 3, which assumes each cycle is the full pressure range identified in the User’s Design Specification for a given pressure vessel design; however, assessment of service data reveals that the actual pressure cycles are more conservative than the design specification. A case study was performed in which in-service pressure cycles were used to re-calculate the design cycles. It was found that less than 1% of the allowable crack extension was consumed when crack growth was assessed using in-service design pressures compared to the original design fatigue life from 2010. Additionally, design cycles were assessed on the 2010 era vessels based on design curves from the recently approved ASME Code Case 2938, which were based on fatigue crack growth rate relationships over a broader range of ΔK. Using the Code Case 2938 design curves yielded nearly 2.7 times greater design cycles compared to the 2010 vessel original design basis. The benefits of using in-service pressure cycles to assess the design life and the implications of using the design curves in Code Case 2938 are discussed in detail in this paper.
Fatigue Crack Growth Study of X70 Line Pipe Steel in Hydrogen Containing Natural Gas Blends
Authors: Chandra Ashwini , Thodla Ramgopal , Prewitt Thomas Joseph , Matthews Wendy , Sosa Siari 
Published: October 2021

Abstract
Blending hydrogen in the natural gas transmission and distribution systems is an option for hydrogen transportation. Integrity management of the existing infrastructure requires a risk evaluation for the planned hydrogen introduction and the challenge of hydrogen embrittlement needs to be considered. The aim of the current study was to evaluate the effect of blending different percentages of hydrogen in methane on the fatigue crack growth rate (FCGR) of X70 line pipe steel. Microstructures associated with base metal, weld center line (WCL) and heat affected zone (HAZ) of girth welds, as well as WCL and HAZ of SAWL seam weld were studied using compact tension specimens based on fracture mechanics. Hydrogen concentrations of 1, 5 and 10 mole% blended in methane were studied. The data was compared to baseline Paris curves in 100% methane as well as the BS7910 in-air mean curve for steel to quantify the increase in fatigue crack growth rate relative to inert environments. In addition, the data was also compared to the ASME B31 curve for carbon steel in hydrogen, to understand the degree of conservatism associated with the ASME curves for the concentrations of H2 evaluated. An increase in FCGR relative to methane baseline was observed for all the microstructures at all concentrations of hydrogen. However, the increase in FCGR relative to the in-air values varied with ΔK. Of the microstructures studied, the base metal showed the highest susceptibility to hydrogen embrittlement for all the hydrogen blends, followed by the girth weld – HAZ location. These two microstructures also had higher hardness compared to the other three locations. A crack growth assessment was also performed for circumferential and axial flaws utilizing the FCGR generated data coupled with pressure cycling data obtained from pipeline operations.
Development of Inhibitor for Corrosion Protection of Condensate Stripping Process in Industrial Coal Gasification Unit
Authors: He Meng , Kang Haoyuan , Liu Juanbo , Chen Sheng , Gong Xueru , Sun Li 
Published: October 2021

Abstract
The condensate involving HS-, CO32−, Cl− and NH4+ usually causes severe corrosion of 20 steel in condensate stripping process of industrial coal gasification unit. The corrosion can easily lead to failure of pipe fittings and vessels, and result in economic losses and personal injury. To protect industrial coal gasification unit against corrosion, five inhibitors including imidazoline, imidazoline amide, mannich base quaternary ammonium salt, pyridine, and sodium molybdate are investigated with experiment of linear polarization curve, polarization curve, electrochemical impedance spectroscopy (EIS). The gas-liquid two phase experimental conditions mixed with suitable concentration of H2S, CO2 and NH4Cl are as close to the industrial alkalescent corrosion environment as possible. The experiment results indicate that two inhibitors of the mannich base quaternary ammonium salt and the pyridine have better effects on corrosion protection than others at the same injection concentration of 100ppm. A new compound inhibitor is developed based on the mannich base quaternary ammonium salt and the pyridine in terms of above results. The new compound inhibitor’s efficiency further reaches to 95.5%, suggesting that the new compound inhibition has better effect on corrosion protection than either of two single inhibitors above.
Influence of Alcohol Additives on the Viscosity and Solubility of Ethanol/Diesel Fuel Blends: A Molecular Dynamics Simulation Study
Authors: Li Xueying , Hou Lei , Chai Chong , He Sichen 
Published: October 2021

Abstract
The viscosity and solubility of ethanol/diesel fuel blends have an important influence on its application in diesel engines. Molecular dynamics simulation was employed to study the effects of different alcohol additives on the viscosity and solubility of the blends between diesel and anhydrous ethanol. Among these alcohols, n-butanol, n-heptanol and n-decanol were selected for investigating the influence of alcohol chain length on solubility and viscosity. The results showed that the viscosity of the blends increased with the increasing of alcohol carbon number. The analysis of diffusion coefficient represented that the alcohol additives enhanced the molecular mobility and activity, and energy analysis indicated that alcohols with higher carbon numbers provided a better inter-soluble capacity. Taking these factors into account, n-heptanol can be recommended as a co-solvent additive for ethanol/diesel system due to the acceptable fuel properties and soluble performance.
The CFD Analysis of Erosion in the Four-Way Pipe of the Heavy Oil Thermal Production Wellhead
Authors: Wang Guotao , Zhang Chongchong , Duan Linlin , Sun Li , Liu Cenfan 
Published: October 2021

Abstract
In this work, the erosion in the four-way pipe of the heavy oil thermal production was studied by experiment and CFD simulations. The metallographic analysis and the micro erosion morphology of the damaged four-way pipe were done and analyzed. The erosion experiment of four-way pipe material ZG(J)35CrMo was carried out by the multiphase flow erosion tester, and the erosion prediction model was established and modified, which was coupled with the Euler-Largrangian gas-solid two phase flow model and used in the CFD simulations. First, the simulation results were compared with the actual invalidation case, through which the validity of the model is proved. Then, the effects of whether the pit defect located in the erodible site or not, fluid velocity, particle diameter and mass flow rate on the erosion rate were investigated using the CFD model. The erosion rate would increase with the fluid velocity, mass flow rate. And the results show that if the pit defect located in the erodible site coincidentally, the erosion rate will increase sharply, maybe several times, which may increase the failure risk of the four-way pipe increase.
Evaluation of Water Flow on Interfacial Strength in PSA Film Delamination
Authors: Inaba Kazuaki , Mashio Ibuki 
Published: October 2021

Abstract
To model the peeling phenomenon during cataract surgery and examine the effect of fluid flow during surgery, we constructed a simplified physical system and compared the case where only static pressure is applied to the adhesive thin film and the case where water flow is applied to the film by suction. From experiments with and without suctioning, the energy release rates of the adhesive thin film were calculated to be approximately 10 N/m, and no significant difference was confirmed with or without suction. We modeled the peeling phenomenon using the cohesive damage model and performed a finite element analysis considering the coupling of the fluid and membrane. The simulation results without suction were in good agreement with the theoretical values of the stress and deflection. When the water flow was applied to collide with the peeling part, the film deflection at the center became smaller, and the radial and circumferential stresses became smaller. From this result, it is shown that the stress acting on the membrane surrounding the crystalline lens can be reduced and peeling can be performed by successfully using the water flow for peeling.
Seismic Test and Seismic Response Analysis of U-Shaped Tubes With Square Array in Steam Generator
Authors: Monde Masatsugu , Ono Naoki , Mineno Tomonori , Hirota Kazuo 
Published: October 2021

Abstract
The heat transfer tubes of steam generators (SG) should not be damaged in an earthquake. The current seismic integrity assessment uses a simple model that integrates multiple pipes. In order to cover the increasing seismic loading conditions under Japanese regulations, more current and realistic estimates are needed than the conservative existing assessment methods.
In this study, all SG components, such as heat transfer tubes and anti-vibration bars (AVB), were modeled, and linear and nonlinear models were developed in order to evaluate more realistic responses and strains.
The natural frequency of the developed linear model and the strain distribution in the tube of the nonlinear model agreed well with the test results in the past. The effect of the AVB stiffness on the strain distribution of the tube has been evaluated by altering the thickness of the AVB.
Study on Method of Response under Turbulence Excitation of Steam Generator Heat Transfer Tube in Two-Phase Flow
Authors: Huang Xuan , Liu Shuai , Feng Zhipeng , Chen Guo , Wu Wanjun , Jiang Xiaozhou 
Published: October 2021

Abstract
The heat transfer tubes of steam generator (SG) are the pressure boundary of primary loop of Pressurized water reactor (PWR), and it is an important barrier to isolate radioactive material. The tubes are prone to fatigue, collision and wear caused by random turbulence excitation of two-phase flow. In the analysis of turbulence excitation, it is necessary to determine the random turbulence excitation based on the dimensionless reference equivalent power spectral density (EPSD), the flow parameters of the secondary side and the correlation length. In single-phase flow, the correlation length can be determined based on the tube gap and tube diameter. Two-phase flow contains two components, the correlation length of random turbulence in two-phase flow is more complicated, and few studies have been done. In this paper, an optimized analysis method on the response of SG heat transfer tube under random turbulence excitation is proposed by studying the EPSD and the correlation length in two-phase flow. Compared with the traditional spectrum analysis method, this method can consider many nonlinear factors such as clearance, collision and friction. Furthermore, the characteristics and mechanism of flow induced vibration of heat transfer tubes can be further clarified, and effective measure can be taken at the design stage of SG to effectively reduce the risk of excessive flow induced vibration.
The Elastic Characterization of Composite Based on Ultrasonic Waves
Authors: Park Y. H. , Dana J. 
Published: October 2021

Abstract
Anisotropic composite materials have been extensively utilized in mechanical, automotive, aerospace and other engineering areas due to high strength-to-weight ratio, superb corrosion resistance, and exceptional thermal performance. As the use of composite materials increases, determination of material properties, mechanical analysis and failure of the structure become important for the design of composite structure. In particular, the fatigue failure is important to ensure that structures can survive in harsh environmental conditions. Despite technical advances, fatigue failure and the monitoring and prediction of component life remain major problems. In general, cyclic loadings cause the accumulation of micro-damage in the structure and material properties degrade as the number of loading cycles increases. Repeated subfailure loading cycles cause eventual fatigue failure as the material strength and stiffness fall below the applied stress level. Hence, the stiffness degradation measurement can be a good indication for damage evaluation. The elastic characterization of composite material using mechanical testing, however, is complex, destructive, and not all the elastic constants can be determined. In this work, an in-situ method to non-destructively determine the elastic constants will be studied based on the time of flight measurement of ultrasonic waves. This method will be validated on an isotropic metal sheet and a transversely isotropic composite plate.