bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stress Evaluation for Class 2 and 3 Pipes With Reinforcement and Wall-Thinning Using Equivalent Stiffness Concept
Authors: Kim Jae-Yoon , Hwang Jin-Ha , Kim Yun-Jae 
Published: November 2023

Abstract
Due to various reasons, wall-thinning can occur in nuclear piping under the operating environment. When wall-thinning occurs in large-diameter Class 2 and 3 pipes, reinforcement is typically applied before replacement. To check structural integrity of reinforced pipes, stress analysis should be performed, which is not straightforward due to three-dimensional nature of reinforced pipes. Full 3-D FE analysis would not be so useful because calculated stresses would not be compatible to the equations given in ASME BPVC Sec. III NC/ND-3650 for Class 2 and 3 piping system.
In this paper, stress evaluation methods for reinforced wall-thinned pipes are presented using the equivalent straight pipe concept. The equivalent straight pipe is defined as the pipe having the same elastic stiffness as reinforced wall-thinned pipe. Analytical expressions for the stiffness of wall-thinned pipe with reinforcement are given for axial tension and bending moment, using which the dimensions of the equivalent pipe can be obtained. The equations in ASME BPVC Sec. III NC/ND-3650 for Class 2 and 3 piping system are then used using the dimensions of the equivalent pipe. Finally, a method to quantify the stress concentration factor of reinforced wall-thinned pipe for fatigue evaluation is presented using the structural stress method.
Theoretical Analysis of Natural Frequencies and Mode Shapes of Three-Dimensional Piping Systems
Authors: Tamura Shinji 
Published: November 2023

Abstract
The vibration of piping system subjected to earthquake is a severe problem. However, the actual piping system is seems to be too complicated to analyze theoretically. Therefore, the finite element method is used to obtain the natural frequencies and mode shapes. For two-span beam, the theoretical method for the natural frequencies are written in the textbook of the vibrations of continuous systems. In this method, the beam is divided at the intermediate support, and the function for the displacement including unknown coefficients is assigned for each divided beam. The boundary conditions for the divided beams yield the characteristic equation for whole beam. In this paper, same approach is extended for the piping system with the elbows.
Mechanical Behavior of 316L-IN718 Interface Produced by Directed Energy Deposition Investigated Using Miniaturized Specimens
Authors: Rzepa Sylwia , Uhlík Matouš , Melzer Daniel , Koukolíková Martina , Konopík Pavel , Džugan Ján 
Published: November 2023

Abstract
Functionally graded materials (FGMs) are materials distinguished by gradual variation in structure and composition within their volume. Nowadays, the development of FGMs is also accelerated by development and expansion of additive manufacturing (AM) technology, which represents a tool for their relatively easy and precise production. This contribution is focused on the characterization of mechanical performance of SS316L-IN718 interface in terms of local tensile behavior that was investigated using miniaturized tensile test (MTT). The tensile behavior of single material zones (SS316L and IN718) as well as two-material interface zones were examined in parallel and perpendicular orientations with respect to the direction of deposition. The strain maps of MTT specimens were compared and used as a tool for failure process evaluation. Beside the sharp two-material interface observed using scanning electron microscope (SEM), a diffusion zone of certain elements was detected via wavelength-dispersive spectroscopy (WDS) line scan. The specimen orientation at the interface is a decisive factor considering the material failure location. The fractographic analysis of MTT specimen machined in vertical orientation showed that the fracture process was observed preferably in the SS316L zone. The strain within IN718 zone was very limited until the end of the test. Contrary to that, in the case of the specimen oriented horizontally, the failure process was initiated in the zone of IN718, which was characterized by higher strength but the plastic capacity was depleted earlier. The recorded stress level yielded the values above these of vertical specimen (SS316L) but below IN718. This suggests that the stress was carried preferably by the IN718 part of horizontally-oriented specimen.
Assessing Residual Stresses in PE-RT Pipes and Annealing Temperature Sensitivity Analysis
Authors: Biradar Arun , Palacios Moreno Jorge , Mertiny Pierre 
Published: November 2023

Abstract
Pipe made from polyethylene with raised temperature (PERT) service capability offers several advantages in terms of material performance, and has broad application in the industry. However, residual stresses are typically present in PE-RT pipe after fabrication, which may affect pipe strength under service conditions. Research on this phenomenon in PE-RT pipe is limited, and hence, the present study investigated the residual stresses and means for mitigating them through annealing at elevated temperatures. Residual tensile and compressive stresses are formed on the inner and outer portions of extruded pipes, respectively, due to the rapid cooling that is typically applied on the outside of the pipes after the extrusion process. The objective of the present work was to assess experimentally residual stresses in PE-RT pipes. In addition, using the experimental methods, a sensitivity study on the annealing temperature for mitigating residual stresses was performed. The experimental procedures were adopted from the ASTM E1928-13 standard. In compliance with this standard, the PE-RT pipes under investigation can be considered as thin-walled tubes for analysis purposes. Moreover, the creep behavior of plastics was incorporated in the final calculation of residual stress values. Two types of slitting methods were applied to assess the residual stresses: (i) To determine the residual hoop stress, a 45-degree section was cut from ring samples, and then the change in ring diameter was observed; (ii) for the longitudinal residual stress, a tongue-like section was cut lengthwise into pipe samples, and the deformation of these sections was observed. For all cutting purposes, coolant was used to avoid any heating effects. The sample lengths varied from 0.2 to 3.0 times the outer pipe diameter. In this manner, effects of specimen length on the test results were ascertained. Experiments conducted for non-annealed PE-RT pipe, as well as pipe annealed at 90 degree Celsius, revealed substantial residual stresses. Using the developed procedures, the study seeks to identify the annealing temperature that yields the lowest possible residual stresses in the PE-RT pipes. Present work includes a discussion on whether the ratio of ideal annealing temperature to melting point can be extrapolated as a key parameter from PE-RT to other thermoplastic polymer materials.
Using Detection Performance to Assess Outlier Sizing on Truncated Data Sets
Authors: Skow Jason , Krynicki Joseph W. 
Published: November 2023

Abstract
The third edition of the American Petroleum Institute (API) 1163 recommended practice (RP) “In-line Inspection Systems Qualification”, released in September 2021, includes many improvements over previous editions including updates to Section 8 “System Results Validation”, which defines the methodologies to validate ILI run measurement tolerances. The recommended practice describes three levels of validation, with ‘Level 3’ requiring operators estimate ILI tool measurement performance with real-world data measured in validation spools and excavation sites. It is an advancement over Level 2 which is a statistical significance test of validation measurements against a vendor specification. Two examples of Level 3 validations are provided in Appendix C, one describes statistical tolerance intervals, the other describes a hierarchical Bayesian model. This paper uses the second model to estimate measurement performance when a data set is truncated.
In a previous paper, the authors described using the Hausman and Wise algorithm to model sizing performance on truncated data sets. When the data is truncated, this algorithm corrects for the ‘missing’ data, improving the results of a linear regression between inspection measurements and validation measurements. However, the algorithm is a based on several assumptions, which do not hold for some outlier data. When an outlier under-predicts the validated size, the Hausman and Wise correction overcompensates because it assumes that every outlier represents a larger number of missed anomalies of similar size. In this paper, we discuss an improvement to the Hausman and Wise algorithm that incorporates the probability of detection of the measurement tool. The probability of detection informs the truncation algorithm by providing the necessary parameters to determine if outliers are purely sizing errors, or whether they also present a risk that a similar sized anomaly was not detected.
This paper includes examples of real field measurement data where the improved algorithm is compared to the original algorithm. In addition, similarly characterized simulation cases are summarized to show edge cases and limits to the algorithm improvement. Finally, the paper offers further improvements that could be made to the truncation algorithm and comments on a similar application for censored data sets.
EPR Piping Material Study: Effects of Sampling Location and Temperature on Low Cycle Fatigue in Air
Authors: Seppänen Tommi , Alhainen Jouni , Arilahti Esko , Solin Jussi , Vanninen Rami 
Published: November 2023

Abstract
Individual research projects often plan experimental test matrices using a restricted batch of materials to study fatigue phenomena and performance. Often the results of these studies are aggregated into databases of material behavior. However, many important scientific findings can be lost in such databases, where complex experimental results can be condensed to generalized tables containing few details. In some scenarios this aggregation and condensing of results in unable to adequately describe the original research.
Dedicated research in Finland aims to support application of risk-informed inspection and LTO strategies, which benefit from addressing material-specific behavior in fatigue management. Initial experimental in-air fatigue results on stainless steel 12” schedule 140 Z2CND1812 N2 class 1 pipe material, which is representative for the EPR reactor in Olkiluoto, were reported in PVP2022-84007. This paper presents an update on continued experimental progress, focusing on material sampling location effects and influence of test temperature on in-air fatigue behavior.
Probabilistic Assessment Tool for Graphite Component Reliability
Authors: Bass Joseph , Iyengar Raj , Ulmer Christopher 
Published: November 2023

Abstract
Assessment of graphite component reliability is important in providing the technical basis to support the safe operation of advanced non-light water reactors. Computational modeling of aging and degradation in graphite components would enable quantitative assessments of stress generation, failure, and associated uncertainties. A graphite modeling tool has been developed in a finite element framework, MOOSE, which was created at Idaho National Laboratory. This tool was developed for the assessment of graphite components intended for nuclear applications. The tool is capable of computing stresses in graphite which result from mechanical loads as well as temperature and irradiation gradients in graphite components. The effect of irradiation creep is included in the graphite behavior model. The graphite tool is also capable of modeling the effects of oxidation. This includes computing temperature dependent density profiles which can be generated by the reaction between graphite and oxygen. Stresses in the oxidized graphite can be computed using material properties which are implemented as a function of mass loss. The tool has been parameterized for graphite grade IG-110, but other grades of graphite can be assessed by providing the necessary material properties. The tool was also developed to work with the graphite assessments in Subsection HH Subpart A in Section III Division 5 of the ASME BPVC. These assessments use a Weibull-based probabilistic approach to assessing a graphite component. Python codes have been created which implement the full and simplified assessments in the 2021 version of the ASME BPVC and utilize the outputs from the MOOSE-based analysis. Initial verification and validation work using this tool has produced promising results.
Dependence of Clearing Effect on Building Dimensions
Authors: Geng Jihui , Thomas J. Kelly 
Published: November 2023

Abstract
Blast waves exhibit both positive and negative phases. The relative magnitude of these phases is a function of standoff distance from the explosion source to targets of interest. When an incident blast wave reaches a target building, the blast wave reflects off the front wall (i.e., that facing the blast source). Both the positive and negative phases of the blast wave are enhanced by the reflection process. A fully reflected blast wave would be produced if an incident blast wave reflected from an infinitely tall and wide wall in a normal orientation. However, when an incident blast wave reflects off a wall of finite size in a normal orientation, rarefaction waves are created at the wall edges and roof, and these rarefactions sweep down from the roof and inward from sides. These rarefaction waves result in a clearing effect for both the positive and negative phases. Clearing relieves some of the applied blast load on the reflected wall for the positive phase. However, this is not always the case for the negative phase. As shown in PVP2022-84288[1], clearing may either relieve or enhance the applied negative phase blast load, depending on the blast wave profile and the wall dimensions.
This paper extends the referenced prior study by examining negative phase clearing as a function of building dimensions and non-planar blast waves. The negative phase blast load adjustment factor (i.e., the ratio of cleared to fully reflected blast load) distribution on the front wall is determined. The purpose of this study is to generate a database of negative blast load clearing for engineering modeling applications.
Challenges in the Life Management of Steam Methane Reformer (SMR) Components
Authors: Bridges Alex , Gagliano Michael , Siefert John , Dalal Mitul , Penso Jorge 
Published: November 2023

Abstract
Steam methane reforming (SMR) is a process in which methane from natural gas is heated, with steam, usually with a catalyst, to produce a mixture of carbon monoxide and hydrogen used in organic synthesis and as a fuel. The steam-gas mixture enters the reformer from the inlet manifold. The reforming reaction is an endothermic reaction requiring a large amount of heat to be supplied to the system. Because of the high temperature and high heat input required for the reaction, it is carried out in directed fired, catalyst filled tubes keeping the temperature of the mixture &gt; 1,500°F (815°C). At these temperatures, methane (CH4) reacts with steam (H2O) to produce hydrogen (H2) and carbon monoxide (CO). The presence of a catalyst helps this process react more quickly and to retain more hydrogen gas. The hydrogen-carbon monoxide mixture exits the reformer via the outlet manifold. In the energy sector, SMR is the most widely used process for the generation of hydrogen.
This paper focuses on the impact of time-dependent damage (creep) on critical steam methane reformer components such as tubes, pigtails, and outlet headers. Specific challenges linked to material variability, well-pedigreed databases, damage development, and standard or feature testing will be addressed.
Free Drop Impact Data Acquisition Using Digital Image Correlation
Authors: Montgomery Veronica , Martinez Oscar , Nogradi Paul , Lowe Lance , Adeniyi Abiodun 
Published: November 2023

Abstract
Radioactive materials are widespread throughout our everyday activities and are used in many different types of industries. There are about 3 million shipments of radioactive materials that occur each year in the United States. Because radioactive materials are so widespread, safety and security are top priorities for the Package Testing Program (PTP) at Oak Ridge National Laboratory (ORNL), and effective and accurate data collection methods are imperative. The packaging used to carry nuclear materials is subjected to rigorous tests to verify its durability. One such test is the free-drop test. Impact data are often collected through an accelerometer attached to the test unit. Unfortunately, these devices are easily broken in the testing environment and are expensive to procure, install, and post process. Digital image correlation (DIC) using high-speed images offers a non-contact alternative. DIC is an optical method that employs image registration techniques to accurately measure changes in images. To verify the suitability of the cameras and process, a test weight was dropped from various heights, and the impact acceleration was derived using DIC. This paper compares the results with data from the attached accelerometer. A total of nine drop tests were performed with three different image capture rates (frames per second) and from three different package drop heights. An ANSYS LS-Dyna model was also used to determine theoretically predicted deceleration rates for comparison with the DIC and accelerometer data.
Linking Deterministic Leak-Before-Break to Probabilistic Framework Using xLPR
Authors: Uddin M. , Cofie N. , Dedhia D. , Dominguez G. , Harrington C. , Glunt N. , Shim D. J. 
Published: November 2023

Abstract
In this paper, several studies are described to compare the current SRP 3.6.3 deterministic leak-before-break (LBB) approach to a corresponding probabilistic approach using the NRC/EPRI developed Extremely Low Probability of Rupture software tool (xLPR) to establish a correlation between the approaches. These studies involve two generic nozzle/pipe sizes (large and medium diameters) with dissimilar metal (DM) butt welds susceptible to primary water stress corrosion cracking (PWSCC). First, deterministic fracture mechanics (DFM) analyses were performed consistent with the SRP 3.6.3 methodology. Then probabilistic fracture mechanics (PFM) evaluations with xLPR were performed assuming single circumferential through-wall flaws consistent with that used in the deterministic approach to establish a correlation. Furthermore, for simplicity, the evaluations were based on a single weld location rather than on a whole piping system.
On a preliminary basis, this correlation indicates that although the deterministic LBB approach may not meet the required SRP 3.6.3 margins in certain cases, a probabilistic LBB approach using xLPR may be used to show low probability of rupture meeting the proposed probabilistic acceptance criteria. However, there are several limitations in developing the correlation that have been identified and more studies are needed to address those limitations.
A Review of Stress Intensification Factors for Reducers
Authors: Shitolé Bhaskar , Heinrichs Cynthia 
Published: November 2023

Abstract
Determining an accurate stress intensification factor (SIF) is important for piping stress analysis. This paper reviews the history of SIF guidelines for reducers and the significance of reducer geometry on the calculated B31J SIF value.
ASME B31.3 Appendix D, which specifies a SIF of 1 for reducers, was removed in the 2020 version of B31.3 which now references ASME B31J. This means all the process piping stress qualified with SIF = 1 for reducers, may now have stress non-compliance with the new SIF of a value up to 2, resulting in layout or/and material changes in piping systems. This paper reviews the history of the development of SIF for reducers and the effect of this code update on default SIF values for reducers. Next, the significance of different reducer geometry parameters is investigated. In the initial stages of design, details such as exact reducer geometry are often not available. Initial analysis will therefore use default SIF values. These default SIF values should be conservative. If an area is a problem for stress, more detailed information can be used to refine the analysis. SIF values were calculated using default B31J values for reducer alpha, r2, and L2 parameters for a range of ASME B16.9 reducers at two different wall thicknesses. The SIF values are significantly higher than 1 and in many cases reach a value of 2. Most of these geometric parameters such as the L2 distance are not controlled by the ASME B16.9 reducer standard, yet they can have a significant effect on the SIF. It is suggested that L2, the distance between the transition radius and the small end of the reducer, should be specified as L2 &gt;= (D2T2)^0.5 in B16.9 to keep reducer SIF values more predictable.
A Method for Modeling Fluidelastic Instability of Tube Arrays Subjected to Two-Phase Flows
Authors: Farani Sani Hossein , Moran Joaquin , Mohany Atef , Hassan Marwan 
Published: November 2023

Abstract
In this paper, a new model is introduced for predicting the tube response and onset of Fluidelastic Instability (FEI) in tube arrays subjected to two-phase cross-flow. The model is developed based on the methodology proposed by Hassan and Weaver [1] for single-phase flows. The velocity and pressure distribution around the tubes are found using the continuity and momentum equations over a simplified flow channel. The two-phase fluid is modelled by discretizing the flow channel into layers, each having a different void fraction based on the homogeneous equilibrium model. The results obtained agree well with the experimental data available, while the computational cost is significantly reduced when compared to other existing models.
Repair of a Check Valve Seal
Authors: Reich Alton , DiSalvo Roberto 
Published: November 2023

Abstract
Nuclear power supply chains increasingly draw from components that are used in industries with less stringent design and quality requirements. A check valve was selected for a nuclear power application that used a design originally developed for process applications. During post-assembly testing of this valve, it was found to have an unacceptable level of seat leakage. The valve was disassembled, and damage to the valve body and other components was discovered. The root cause was traced to problems during initial assembly that were a direct result of the valve design.
This paper discusses the damage that was found on the valve body, sealing components, seal retaining ring, and draw plate. The manufacturing issues that contributed to the sealing failure are also discussed. The valve sealing mechanism was redesigned in order to correct the problem and repair the already manufactured valves. Several options were considered for repairing the valves and correcting the manufacturing and design defects. Each of these options had disadvantages, and the relative strengths and weaknesses of each option are considered. The selected repair method was qualified using Code rules and the repaired valves were tested to ensure that they met the design requirements. Finally, we discuss lessons learned that can be applied to future valve designs and efforts to utilize equipment originally designed for other industries in nuclear power applications.