bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessment of the Impact of Elevated Temperature Design Code Revisions on Creep Damage Estimation
Authors: Ando Masanori , Okajima Satoshi , Takasho Hideki 
Published: November 2022

Abstract
Two significant improvements were achieved in 2019 and 2021 Editions of ASME Boiler and Pressure Vessel Code, Section III, Division 5. One is an update of allowable stress values in Gr.91 steel as 9Cr-1Mo-V steel. The time for which the values of Sr, expected minimum stress-to-rupture, is defined were extended from 300,000 to 500,000 hours and the values in relatively high temperature and long-term region were reduced compared with those in the region less than 300,000 hours. The other is that the equations for monotonic stress-strain curves and creep strain curves were provided. These improvements affect the creep damage calculation in the evaluation of creep-fatigue damage. The reduction of Sr values increases creep damage and providing the equations allows calculating the creep damage more precisely. In this study, the impact of these improvements on the creep damage calculation is assessed by some sample problem calculations. The stress dividing coefficient of K′ for Gr.91 was improved from 0.9 in 2017 Edition to 1.0 in 2019 Edition. The effect of the improvement on creep damage was also assessed. The total creep damage almost tripled by using the updated Sr table, although and decreased by about 20% by using the provided equations rather than graphic calculation in a sample problem case. The change of the value of K′ halved the creep damage in the sample problem case. The creep damage calculations during the stress relaxation were based on the Division 5 procedures of HBB T-1433(a) and (b), and these results were compared to a calculated result using creep damage calculation procedure using the elastic follow-up concept adopted in the Japanese elevated temperate design code. Material test results of notched bar specimens are also used for comparison. The calculated result indicated that the procedure using the elastic follow-up concept was comparable to those by HBB T-1433(a) and (b), while calculation using the elastic follow-up concept is easier than that of HBB T-1433(a) and (b).
Disorders in Periodic Support for Pipeline Conveying Fluid
Authors: Zeng Qingna , Wang Donghui , Zang Fenggang , Zhang Yixiong 
Published: November 2022

Abstract
This paper studies the influence of disordered parameters on vibration transmission characteristic of pipeline structure with periodic support. Transverse Band Gap structures (BGs) for perfect period and frequency response function (FRF) for finite periods are investigated and fit well with each other. By introducing a certain degree of uncertainty level, interval method is used to convert uncertain parameter problem into two deterministic models. FRF for near-periodic structure with single disorder and BGs for quasi-periodic structure with multiple disorders are investigated concerning support stiffness and periodic length. The existence of disorders in periodic structure would always reduce the attenuation intensity and interval, and some disturbance would even generate new intermediate attenuation zones. Elastic wave propagation with periodic support is much more sensitive to periodic length rather than support stiffness, as the sensitivity is closely related with attenuation mechanism. Therefore, such defects should be carefully avoided in design and manufacturing this kind of periodic pipeline structures. The work in this paper enriches the stability analysis of the pipeline structure with periodic support, and provides reference for the research of noise and vibration reduction of pipeline system in practical engineering.
K-Factor Testing of PTFE-Coated Studs
Authors: Hamilton Scott , Meigs Dan , Blake Tom , Oldiges Don 
Published: November 2022

Abstract
Vendors offer PTFE-coated studs to provide corrosion resistance in harshly corrosive environments. Vendors advertise PTFE-coated studs as having reduced K-Factor compared to uncoated studs, and differences of opinion exist on whether or not lubrication is required when assembling joints with PTFE-coated studs. In fact, some end users have adopted the practice of assembling joints with PTFE-coated studs without lubrication when the stud is used for the first time and then applying lubrication when studs are reused.
This study tested the K-Factor of a set of studs in different sizes from seven vendors to determine what K-Factor should be expected when using PTFE-coated studs, how much variation in K-Factor one should expect between vendors and sizes, and the effect lubrication has on variability in K-Factor. K-Factors were derived using an automated test fixture that plotted K-Factor vs bolt load across a range of loads from 30 ksi to 80 ksi.
This study found there is significant variation in K-Factor from vendor to vendor, from stud size to stud size, and even within individual lots of a single size from a single vendor. The study found that without lubrication, the average K-Factor increased significantly with bolt load, making prediction of gasket stress difficult. The study concluded that properly lubricating PTFE-coated studs during assembly significantly reduces the variability seen in unlubricated studs.
Seismic Test and Seismic Response Analysis of U-Shaped Tube Bundle With Triangular Arrays in Steam Generator
Authors: Hirota Kazuo , Monde Masatsugu , Ono Naoki , Nakamori Tomohito , Matsubara Masahito , Mineno Tomonori , Taguchi Koshi 
Published: November 2022

Abstract
Ensuring a complete integrity of steam generators’ tubes during earthquakes is critical. So far, excitation tests have been conducted for various square array tube bundles in order to grasp vibration behavior during seismic excitation. A seismic analysis method using a simple model has been developed and subsequently verified by comparing the results against those of the above mentioned tests.
In this study, seismic excitation tests were carried out for a U-shaped tube bundle with a triangular close-packed array using a full-scale test specimen as the triangular tube array with thinner anti-vibration bars (AVBs) has different vibration characteristics compared with a squared array one.
Natural frequencies, modes and stress distribution in the tube bundle, obtained during the experiment, were applied in order to verify the seismic analysis method through the use of a linear analysis model with all tubes and AVBs connected to each other by linear springs as well as with a nonlinear analysis model with gap elements to simulate contact and sliding between all tubes and AVBs.
The vibration displacement of the top of the tube bundle calculated by the linear model were in good agreement with the test result. Stress distribution in the tube array calculated using the nonlinear model were in good agreement with the test result. It has been concluded that the linear and nonlinear analysis models are applicable to seismic analysis including for the case of a U-shaped triangular tube array in a steam generator.
Modeling Refractory Stiffness for Piping Flexibility Analysis
Authors: Nadarajah Chithranjan 
Published: November 2022

Abstract
Refractory is commonly used in pipes for cold wall design. Generally, to analyze refractory lined piping, a piping stress analysis is done using commercially available piping flexibility analysis software. In the stress analysis, the refractory weight and stiffnesses are included in the piping model. From the piping analysis, the calculated sustained and expansion stresses are compared with ASME B31.3 [1] allowable stresses and the forces and moments from the analysis are used in the design of attached equipment (vessel nozzle, valves, expansion joints etc.) piping restraints and supports.
In this paper it will be shown that for a piping stress analysis, using the combined stiffness of the refractory and pipe material on the straight section of the pipe is satisfactory but when it is used on the bends, it will result in un-conservative resultant forces and moments from thermal expansion. To obtain satisfactory resultant forces and moments, the calculated refractory stiffnesses on the bends should be increased in the piping model. The piping stress analysis results were verified with finite element results and past experimental work.
A Critique of Steam Hammer Load Analysis Methods
Authors: Walters Trey W. 
Published: November 2022

Abstract
One of the key assumptions in modern steam hammer load analysis is based on an incomplete understanding of steam wave behavior. Compression waves generated after a valve closure steepen much more quickly than previously thought. The resulting forces generated on pipe runs separated by elbows can be significantly higher than those predicted using current methods. To be more specific, current methods may give unconservative pipe force estimates — potentially resulting in unsafe designs. Using a more complete understanding of gas wave speed, quantitative examples are given which show the larger forces which occur as a result of wave steepening. Suggestions on how to improve load estimation are discussed.
Effect Of The Mean Temperature of Storage Site on Chloride-Induced Stress Corrosion Cracking Rate in ASME Code Case N-860: Case Study
Authors: Jeong Jae-Yoon , Kim Yun-Jae , Lam Poh-Sang , Kim Seunghyun , Kim Gi-Dong 
Published: November 2022

Abstract
Spent nuclear fuels (SNFs) are stored in stainless steel canisters at Independent Spent Fuel Storage Installations (ISFSIs) typically near the seashore. During long-term storage of these canisters in the dry cask storage system (DCSS), chloride-induced stress corrosion cracking (CISCC) could occur due to the deliquescence of concentrated salt deposits on the canister surface. To evaluate such flaws on the accessible exterior metallic portions of containment systems while in service, the ASME Section XI Code Case N-860 provides inservice inspection requirements for aging management of canisters manufactured with welded austenitic stainless steels. It is noteworthy that CISCC crack growth rate (CGR) model in Code Case N-860 consists of the constitutive equations with temperatures (canister surface temperatures, storage site yearly mean temperature, and ambient temperature measured at overpack inlet) and is independent of stress intensity factor or other environmental factors.
In this work, the mean temperature effect of the local storage site on the CGR is analyzed based on the CISCC CGR model in Code Case N-860. The specified mean temperature in the Code Case is calculated yearly however, the crack growth by CISCC can be evaluated differently if the mean temperature of storage site with a large annual range of temperature such as South Korea is applied. In that case, the monthly mean temperature is adjusted as the yearly mean temperature so the effect of averaging range for calculating the mean temperature is analyzed. Firstly, climate data of some candidate sites for the storage in South Korea are measured from Korea Meteorological Administration (KMA). The climate data of the Diablo Canyon Power Plant located in California (United States) is obtained from National Weather Service (NWS) for comparison. Yearly data from 2012 to 2020 are applied and the crack growth is estimated for sites of different annual ranges.
Fatigue Design Sensitivities of Stationary Type 2 High-Pressure Hydrogen Vessels
Authors: Emery John M. , Grimmer Peter , Wheeler Robert , San Marchi Chris , Ronevich Joseph 
Published: November 2022

Abstract
Type 2 high-pressure hydrogen vessels for storage at hydrogen refueling stations are designed assuming a predefined operational pressure cycle and targeted autofrettage conditions. However, the resulting finite life depends significantly on variables associated with the autofrettage process and the pressure cycles actually realized during service, which many times are not to the full range of the design. Clear guidance for cycle counting is lacking, therefore industry often defaults to counting every re-pressurization as a full range pressure cycle, which is an overly conservative approach. In-service pressure cycles used to predict the growth of cracks in operational pressure vessels results in significantly longer life, since most in-service pressure cycles are only a fraction of the full design pressure range. Fatigue crack growth rates can vary widely for a given pressure range depending on the details of the residual strains imparted during the autofrettage process because of their influence on crack driving forces. Small changes in variables associated with the autofrettage process, e.g., the target autofrettage overburden pressure, can result in large changes in the residual stress profile leading to possibly degraded fatigue life.
In this paper, computational simulation was used for sensitivity studies to evaluate the effect of both operating conditions and autofrettage conditions on fatigue life for Type 2 high-pressure hydrogen vessels. The analysis in this paper explores these sensitivities, and the results are used to provide guidance on cycle counting. In particular, we identify the pressure cycle ranges that can be ignored over the life of the vessel as having negligible effect on fatigue life. This study also examines the sensitivity of design life to the autofrettage process and the impact on life if the targeted residual strain is not achieved during manufacturing.
An Initial Assessment of the Creep-Rupture Strengths for Weldments With Alloy 800H Base Metal and Alloy 617 Filler Metal
Authors: Rupp Ryann E. , Sham Ting-Leung 
Published: November 2022

Abstract
In Section III, Division 5 of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Alloy 800H is qualified for elevated-temperature nuclear construction for temperatures up to 760°C (1400°F) and a maximum service life of 300,000 hours. There are two permissible filler metals for Alloy 800H weldments specified in Division 5: ENiCrFe-2 (Alloy A) and ERNiCr-3 (Alloy 82). Low creep-rupture strengths of these weldments at the upper limits of the qualified temperatures and service lives may restrict the design envelope for elevated-temperature nuclear construction with Alloy 800H. As a result, an alternative filler metal is desired to improve the creep-rupture strengths of Alloy 800H weldments for the qualified temperatures and service lives.
This work investigates an overmatched filler metal. Specifically, a weldment with Alloy 800H base metal and Alloy 617 filler metal fabricated by semiautomated gas tungsten arc welding is investigated. A scoping creep-rupture test program was conducted of cross-weld specimens at temperatures ranging from 750 to 1000°C (1292 to 1832°F). Preliminary results on the creep-rupture strengths of the Alloy 800H weldment with an Alloy 617 filler metal do not show significant improvement compared to the filler metals currently qualified in Division 5 for Alloy 800H weldments. Consequently, work is in progress to investigate a matching filler metal.
On the Effect of Hot-Box Size on Coke Drum Skirt Fatigue Life
Authors: Fernando John , Kwok Henry , Wong Leanne , Chan Luke 
Published: November 2022

Abstract
Due to the severe cyclic thermal and structural loading that coke drums experience during operation, thermo-mechanical low-cycle fatigue failure has become a prominent consideration in the design of coke drums. Fatigue failure is commonly observed at the skirt-to-shell attachment weld, due to thermal gradients that develop during heating and cooling cycles. To reduce temperature differences between the coke drum shell and skirt near the attachment weld, “hot-boxes” are often implemented in skirt designs. Hot-boxes are enclosed regions of space near the attachment weld that maintain the skirt at temperatures similar to the nearby shell through natural convection and radiation. The present study investigates the effect of hot-box emissivity and height on the fatigue life of the attachment weld for skirt designs with and without keyholes. The results presented herein indicate that, for the skirt height investigated, fatigue life has negligible sensitivity to the height of the hot-box when no keyholes are present on the skirt. In contrast, varying fatigue performance is observed as a function of hot-box height when keyholes are included as part of the skirt design. Although the functional relationship between hot-box height and fatigue life for the skirt design with keyholes is non-monotonic, the results provide directional insight into the optimization of hot-box size.
Computational Fluid Dynamics Modeling of Dry Cask Simulator With Crosswind
Authors: Jensen Ben J. , Suffield Sarah R. , Higley Megan E. 
Published: November 2022

Abstract
The purpose of this study is to create a STAR-CCM+ model of the Belowground Vertical Dry Cask Simulator (BVDCS) at Sandia National Laboratories (SNL) and validate the model with SNL’s experimental results. The BVDCS consists of a single boiling water reactor assembly fitted with electric heaters encompassed by a containment vessel and shell to represent a belowground spent nuclear fuel (SNF) dry storage system. Blowers are located near the inlet and outlet of the BVDCS to simulate crosswind conditions. In addition to the experimental results, the STAR-CCM+ model developed for this study is compared with a previous computational fluid dynamics (CFD) model in a different software program, which is used as a software-to-software benchmark. The experimental results provide a dataset to compare the STAR-CCM+ model results for a variety of different conditions. The main objective is to validate and improve STAR-CCM+ CFD models for spent nuclear fuel storage systems with explicitly modeled external environments and “wind driven” crossflows. These CFD models aid in the study of external particle deposition in spent nuclear fuel storage systems, which is important to predicting the significance of chloride induced stress corrosion cracking (CISCC). In addition to experimental comparison, a sensitivity analysis is performed using the STAR-CCM+ model. The sensitivity analysis provides a quantitative assessment of the sensitivity of various parameters. This helps provide information on various parameters that are of particular importance to constructing a model representative of real life systems. The STAR-CCM+ model compared well to the experimental results showing similar responses to changes in crosswind flow, and however several parameters are identified for model improvement.
Baseline Design of High-Pressure Confinement Vessel for Proton Radiography of Shock Physics Experiments
Authors: Spernjak Dusan , Fister Matthew , Fehlmann Kevin , Scarafiotti Jesse , Lakey Matthew , Bustos Gerald , Cardon Devin 
Published: November 2022

Abstract
A unique vessel system is being developed to facilitate proton imaging of small-scale shock physics experiments at Los Alamos National Laboratory (LANL). The main components of the system are the Inner Pressure Confinement Vessel (IPCV, which hosts the physics experiment), the Outer Pressure Containment Vessel (OPCV) and Beam Pipes and Auxiliary Hardware (BPAH). The IPCV is an explosively loaded high-pressure vessel which is mounted inside the statically loaded OPCV. The OPCV is attached to a proton beamline. The OPCV and beam pipes form a containment pressure barrier. The detonation of high explosive (HE) inside the IPCV drives material to extreme loading conditions, which are imaged using a proton beam and an imaging system. The IPCV needs to satisfy the ASME Boiler and Pressure Vessel Code, Section VIII, Division 3, Code Case 2564, while allowing for maximum resolution of proton radiography across a sufficiently large field of view.
The main components of the IPCV are the vessel body, top and bottom covers, side covers, and radiographic window assemblies. The covers have different feedthroughs mounted on them, such as feedthrough devices for sending or receiving electrical and optical signals across the pressure boundary. The covers also have gas lines with valves for venting the vessel volume. The sealing strategy incorporates a tortuous path and a minimum of 3 O-rings at each vessel cover. The O-ring grooves are designed and tested to seal the vessel before and after the explosive experiment, and to minimize the burp (limited release) during the explosion. While the IPCV is designed for a relatively small HE amount of 30 g TNT equivalent, the radiographic window is located only a few cm away from the HE, which is unique to this specialized high-pressure vessel. To achieve the optimal imaging resolution across the required field of view of 2cm by 2cm, the radiographic windows need to be very thin, located extremely close to the HE, and made of low-attenuating material such as Beryllium. This paper provides an overview of the baseline design, analysis, and testing of the IPCV and its subassemblies.
Numerical Simulation on the Influence of Elbow Structure on Hydrogen Flame Propagation Process in Pipes
Authors: Mei Yuan , Shuai Jian , Qi Sheng , Huang Zhonghong 
Published: November 2022

Abstract
Combustible gas accounts for an increasing proportion of energy in countries. As the main transportation tool of combustible gas, the safety of pipeline has always been the focus of researchers. When the gas explodes, the accident consequences are greatly affected by the pipeline structure. The study on the hydrogen explosion characteristics of a typical pipe structure (elbow structure) is carried out in the paper. The results show that in pipes with large elbow angles, the flame front can form local cavity regions as flame passes through the elbows. The influence of elbow structure on flame propagation is mainly concentrated in the middle and late stages. In the middle stage, the elbow structure creates a relatively closed space in advance, so that the speed peak-2 occurs earlier than the straight pipe. In the later stage, the acceleration effect produced by the outer wall (concave wall) plays a leading role, and the flame accelerates for the third time after passing through the elbow. There is an interactive relationship between the development of the explosion overpressure and the flame propagation in the elbow.
Gaseous Hydrogen Charging and Fatigue Testing on IN718
Authors: Ebling Fabien , Wackermann Ken 
Published: November 2022

Abstract
IN718 is a precipitation hardened nickel-based superalloy, which is well known for its high strength, good corrosion and creep resistance from low to high temperatures. It is therefore a popular material for numerous applications. Nevertheless, it is known that hydrogen can strongly affect the mechanical properties of IN718. Some questions still need to be clarified to ensure the safe use of components in a hydrogen environment.
In this work, the hydrogen uptake in a gaseous hydrogen environment and tensile and fatigue properties of pre-charged IN718 were investigated. Specimen were charged at 350°C and 100 bar hydrogen pressure. It turned out, that saturation was reached after 10 days with a hydrogen content of about 27 wppm. Tensile tests showed a loss of elongation to failure and reduction of area for the pre-charged specimen. Hydrogen effects were also evident in the low cycle fatigue test. The cycles to failure were significantly reduced. Investigations of the fracture surfaces showed clear differences in crack growth of non-charged and pre-charged tensile and fatigue specimen.