bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effect Mechanism of Hydrodynamic Factors on Naphthenic Acid Flow-Induced Corrosion
Authors: Lyu Yunrong 
Published: November 2019

Abstract
Hydrodynamic factors are the important factors affecting the flow-induced corrosion of naphthenic acid. The effect mechanisms of hydrodynamic factors such as flow velocity, flow pattern, erosion angle and multiphase flow, etc. on the flow-induced corrosion of naphthenic acid are analyzed comprehensively, and the effect mechanisms of critical hydrodynamic parameters such as surface shear stress and near-wall turbulence intensity, etc. on naphthenic acid corrosion are explained. It is pointed out that in the flow-induced corrosion system of naphthenic acid, hydrodynamic factors such as flow velocity, flow pattern, erosion angle and multiphase flow, etc. influence the erosion intensity and mass transfer process generally by changing the magnitude of surface shear stress and near-wall turbulence intensity, thus affecting the severity of corrosion.
A Proposed Framework for the Training and Qualification of Personnel Involved in Field Machining of Bolted Flanged Joints
Authors: Rodery Clay D. , Hamilton Scott , Ferguson Neil 
Published: November 2019

Abstract
One important element in the integrity of bolted flanged joints is the condition of the flange seating surfaces which contact the gasket. Just as the competence of the bolted joint assembler is a key element in the integrity of an otherwise properly designed and constructed bolted flanged joint assembly, when the decision is made to re-machine the gasket seating surfaces on the flange(s) the competence of the personnel who operate the field machining equipment can have an impact on those features of the flanges that affect alignment and surface finish. This paper outlines a proposed industry framework for the training and qualification of personnel who conduct field machining of flanges that is like what is currently in Appendix A of ASME PCC-1 for bolted joint assembly personnel.
Flow-Excited Acoustic Resonance Vibration Mitigation of Reactor Inlet Piping by a Perforated Annulus
Authors: Pontaza Juan P. , Pudwill Wesley K. 
Published: November 2019

Abstract
Piping vibration had been observed in one of our refinery’s reactor inlet piping for several decades. Vibration levels in inlet piping for reactor ‘D’ and ‘E’ were highest, relative to those in reactor ‘A’, ‘B’, and ‘C’. To cope with the vibration, design changes to small-bore branch connections had been implemented to reduce susceptibility to the vibration. A recent increase in production demand made the vibration levels more evident and a production constraint was imposed after an MOV gas seal failure.
Analysis identified the root-cause as flow-excited acoustic resonance of (almost) coaxial closed side branches in the flow path. The selected vibration mitigation solution involved installing a perforated annulus in the main line, in front of the mouth of the (almost) coaxial closed side branch acoustic resonator. Before fabricating and installing the perforated annulus, it was decided to evaluate its expected performance by means of computational fluid dynamics (CFD) and structural stress finite element analysis (FEA). This paper gives an account of the selection of the perforated annulus as the preferred vibration mitigation solution and its evaluation by means of high-performance computing CFD and FEA.
The CFD and FEA analysis showed that the perforated annulus would perform as intended and mitigate the piping vibration. The perforated annulus was fabricated and installed in the inlet piping for reactor ‘D’. Piping vibration was observed to be mitigated, even when flowing above the design rate. The perforated annulus vibration mitigation solution was replicated in the inlet piping for reactor ‘E’. The production constraint has since been lifted.
Failure Modes of Piping Systems Under Seismic Loading and Evaluation
Authors: Kai Satoru , Otani Akihito 
Published: November 2019

Abstract
Failure modes of piping systems under seismic motions were discussed for several decades if the fatigue failure is dominant or there is some possibility that the plastic collapse could occur. A handful of ratchet-buckling failure observed in Pipe Fittings Dynamic Reliability Program by EPRI was frequently taken up as the evidence of the plastic collapse, and inclusion of seismic response on structures into the Primary stress evaluation for piping systems in the code evaluation was considered to be conventionally justified. Although prevention of the plastic collapse type failure is the purpose of imposing the Primary stress evaluation, the other experimental tests conducted in several countries for decades were unable to represent the plastic collapse of piping components exposed to seismic loading and the discussion was abandoned for a while. However, the drastically increased design seismic motions for nuclear power plants due to several huge earthquake occurred in Japan reminded us of exploring the fact of the plastic collapse and the necessity of the Primary stress evaluation.
The load classification concept proposed by the authors introduces 3 conceptual force terms from the equation of motion to clarify the seismic loading from the aspect of the correlation of the said force terms. Based on the finding from the concept that the input force amplitude is to be evaluated for Primary stress, the gross-plastic deformation on a single cantilever with elastic-plastic analyses using multiple of single-cycle sinusoidal forcing functions was compared with the input force term. When the plastic collapse is defined as a gross-plastic deformation, the level of plastic collapse was found to be possibly anticipated with a static force evaluation that can be substitute for the conventional Primary stress evaluation with the dynamic response analysis.
A New Accurate Quantitative Inspection Technology to the Corrosion for the Offshore Erect Pipeline
Authors: Guangpei Cong , Yujiang Sun , Guanglei Lv , Lv Yunrong , Fu Shuxia 
Published: November 2019

Abstract
The erect pipe is a dangerous one with a special double concentric pipes, in which the inner pipe and outer pipe are both corroded on the offshore platform so that a effective corrosion inspection is needed to measure the thinning to the inner pipe and outer pipe at the same time. In addition, because of the narrow space in the offshore platform, it is difficult for the digital X-ray tangential photography (DR) to be implemented during the operation because of the larger X-ray dose that is enough to threaten the personal safety according to the standards in China. Hence, a special inspection tech is demanded to obtain the wall thicknesses of erect pipe which is the most important information to the corrosion management. In this article, A new measuring tech is proposed for the concentric multi-pipe structure to dissolve the bottleneck on the inspection of the offshore erect pipeline. Through the tangential scanning and a wall boundary identifying algorithm, the tech can accurately measure the wall thicknesses of erect pipe, and the ray dose can also be decreased about to the one thousandth of traditional DR, which can guarantee the safety of a inspection and monitoring during the operation in a narrow space as the offshore platform. Besides, the low dose of ray doesn’t influence the accuracy of the measurement which can still be kept into 0.2mm according to the theoretical analysis and experimental data.
Fracture Toughness Criteria of Irradiated Austenitic Stainless Steels for Structural Integrity Evaluation of BWR Internal Components
Authors: Hayashi Takahiro , Tanaka Shigeaki , Abe Tomonori , Sakuraya Seiji , Ooki Suguru , Kaminaga Takayuki 
Published: November 2019

Abstract
Continuous improvement of the structural integrity evaluation methodology in the plant life management (PLM) evaluations is of increasing importance for aged light water reactors. In PLM evaluations, structural integrity evaluations are required for degradation mechanisms considered in the subject equipment and components. Austenitic stainless steels used in reactor internal components are known to show decreases in ductility and fracture toughness due to accumulated neutron irradiation damage. In Japan, “Rules on Fitness-for-Service for Nuclear Power Plants of the Japan Society of Mechanical Engineers Code (JSME FFS Code)” provides fracture evaluation method and criterion, based on the linear elastic fracture mechanics, for irradiated stainless steels of boiling water reactor (BWR) internal components. The fracture toughness criterion, however, was developed with limited materials testing data and knowledge available at that time and it has not been revised since the code originally established.
In this study, fracture toughness criteria for structural integrity evaluation were discussed and developed with the latest database on fracture toughness of irradiated austenitic stainless steels, including additional material testing data obtained in this study for the neutron fluence range of interest from 1 to 3 dpa. First, the fracture toughness data of austenitic stainless steels irradiated in BWR conditions were compiled to evaluate the correlation between fracture toughness and neutron fluence. Material characteristics potentially affecting fracture toughness, such as chemical composition and specimen orientation, were also considered and discussed in the development of the fracture toughness criteria. Based on the results, the fracture toughness criteria for irradiated austenitic stainless steels were proposed for fracture evaluation of the BWR internal components.
Research and Development of Three-Dimensional Isolation System for Sodium-Cooled Fast Reactor: Part 3 — Characteristics for Elements on Basis of Half-Scale Loading Tests
Authors: Somaki Takahiro , Fukasawa Tsuyoshi , Okamura Shigeki , Miyagawa Takayuki , Uchita Masato , Yamamoto Tomohiko , Watakabe Tomoyoshi , Fujita Satoshi 
Published: November 2019

Abstract
The authors have been developing the three-dimensional isolation system for a Sodium-cooled Fast Reactor, and reported the details of characteristics of disc springs and vertical oil dampers on the basis of full-scale loading tests [1].
To clarify the fundamental characteristics of the three-dimensional isolation system, the loading tests using a half-scale assembled specimen have been planned, which is composed of a rubber bearing, disc spring units, the horizontal supporting functions, the smoothly sliding elements, and the rotate restraint elements.
This paper describes each characteristic of the rubber bearings, disc springs and sliding element before assembling a half-scale specimen of the three-dimensional seismic isolation system by the static or dynamic loading. The applicability of design method, the scaling effect in disc springs, and the dependence on the friction coefficient of the sliding elements were investigated and confirmed. Additionally, the method of minimizing the variation of force-displacement relationships between four disc spring units, each of which has the three disc springs stacked in parallel and six disc springs stacked in series, was studied.
It should be noted that this paper is in series from Part 2 [1] held on 2018PVP.
Mode I Ductile Crack Growth of 1TCT Specimen Under Large Cyclic Loading: Part III
Authors: Hojo Kiminobu 
Published: November 2019

Abstract
Fitness for service rules and a calculation method for ductile crack growth under large scale plastic cyclic loading have not been established even for Mode I. In a paper presented at the PVP2018 conference the authors presented methods to establish how to determine the parameters of the combined hardening plasticity rule and applied it to simulate the ductile crack growth behavior of 1TCT specimens of the different load levels. Also, ΔJ calculations using the reference stress method, and a ΔJ-basis fatigue crack growth rate derived from that on ΔK-basis according to JSME rules for FFS were applied to estimate the crack growth under cyclic loading in excess of yield. Since in the 2018 paper identified some gaps were found between experiments and the predicted crack growth behavior, several equations of the reference stress method are evaluated in the present paper. Additionally, the prediction procedure using the ΔJ calculation by the reference stress method and the da/dN−ΔJ curve based on the JSME rules for FFS are applied to pipe fracture tests under cyclic loading. Their applicability is discussed for the case of an example piping system.
Technical Progress in Chinese Standard of Ultra-High Pressure Vessels
Authors: Chen Zhiwei , Li Tao , Yang Guoyi , Zheng Jinyang , Deng Guide 
Published: November 2019

Abstract
GB/T 34019-2017 “Ultra High Pressure Vessels” is the most important national standard that applies to pressure vessel which design pressure value is greater than or equal to 100MPa (14.5ksi). There is no standard for Ultra-high Pressure Vessel, Then this standard fills the gap in the standard system of pressure equipment in China. This paper mainly introduces the concept and main content of the new national standard, including the materials, design methods and nondestructive testing of ultra-high pressure vessel.
Ultrasonic Phased Array Inspection With Water Wedge for Butt Fusion Joints of Polyethylene Pipe
Authors: Miao Cunjian , Qin Yinkang , Guo Weican , An Chengmin , Ling Zhangwei , Chen Zhifa 
Published: November 2019

Abstract
Polyethylene pipe has been used widely in gas transportation and nuclear safety-related cooling water applications due to its exceptional resistance to corrosion and erosion. Butt fusion joint is one of the main welding forms for polyethylene pipes. Ultrasonic technique is a typical nondestructive examination technique. To overcome the coupling problems when inspecting butt fusion structures, an inspection technique of ultrasonic phased array using water wedge is proposed to solve the coupling matching and to increase the ultrasound amplitudes. The influences on the imaging of the parameters (such as the angle and height of the water wedge), the array element specifications, and the aperture, were investigated via simulations. The parameter optimization was conducted to establish a suitable detection process. After that, the related probe and a simulated water wedge were designed based on the results and manufactured, in which the simulated wedge as a specific probe holder could adjust its own incident angle and array height. Meanwhile, a typical DN315 pipe of PE 100 was made with some typical artificial defects in it. Experiments were conducted, and the results showed that the proposed water-wedged ultrasonic phased array technique is suitable for butt fusion joint inspection.
CFD Analysis and Structural Safety Assessment of a Bypass Mitigation Device Used During a Ti-SGTR Accidental Release From a MSSV
Authors: Wang Wung Jae , Yim Man Sung 
Published: November 2019

Abstract
In Nuclear power plants, Main steam safety valve (MSSV) is a barrier to prevent overpressure of steam flow by opening the secondary cycle to the atmosphere. Since MSSVs operate at condition of high temperature and pressure, they have possibility for stuck-open failure. If this accident occurs, large amount of steam or gases release through failed MSSV. It may lead Thermally-induced Steam generator tube rupture (TI-SGTR) due to sudden high gradient of temperature and pressure. With loss of electrical power, TI-SGTR occurs, Core will start to melt in 2–3hours after loss of electrical power. When TI-SGTR occurs with core melt, Leakage of radioactive material occurs through MSSV to environment. Though the probability of an accident is very low, the release of radioactive material can lead large cancer risk to the public. Therefore, many studies to mitigate the radioactive materials are in progress such as diversion to containment building or capturing with external mitigation system.
In this study, we are focusing on this capturing device. The objective of this study is to analyze integrity of mitigation device using fluid behavior from MSSV to capturing pipe. Hydraulic conditions at safety valve inlet were used from previous researches. Using commercial simulation software, computational fluid dynamics (CFD) analysis was performed for distribution of fluid temperature, pressure, velocity in MSSV and pipes. For structural safety assessment, 1-way Fluid-Structure interaction (FSI) method was used. CFD result was applied for load on structure surfaces to simulate transient structural analysis of mitigation device. As a result, stresses, strains of capturing pipe were calculated and integrity was discussed.
Further Investigation Into the Damage Tolerance of Different Coke Drum Support Skirt Designs
Authors: Kummari Seetha Ramudu , Prueter Phillip E. , Bifano Michael F. P. , Seijas Antonio J. , Hantz Benjamin F. 
Published: November 2019

Abstract
Evaluating the behavior of coke drums is challenging due to the randomness and uncertainties in typical cyclic loading conditions. Severe fluctuations in temperature and stress during the quench portion of the thermal cycle can often lead to distortion, fatigue damage, and ultimately, cracking. Since the evolution of damage in the coke drums is a cycle-dependent process, a snapshot of strain or distortion data generally has limited value in quantifying remaining life. Advanced fatigue methods and damage models are usually required to address the permanent irreversible damage and material degradation that is produced throughout multiple cycles. This paper represents an advanced finite element analysis (FEA)-based study that is a continuation of the work published in PVP2017-65807[1], with new coke drum support skirt geometries included in the comparisons. The thermal-mechanical behavior of five different support skirt designs; Egg-in-Cup, Tangential, Forged, Sliding, and Welded, are investigated, and relative fatigue life predictions are discussed for each type of design using consistent, idealized thermal transients.
The Use of Different Media in Leakage Tests
Authors: Schaaf Manfred , Herkert Frank , Arnett Adam 
Published: November 2019

Abstract
Previously, in Europe, in gasket tests mainly Nitrogen was used as the test medium. This medium was easy to handle, safe and cheap to buy. With increased sealing requirements on the sealing elements, however, a test medium had to be used, with which smaller leakage quantities can be reliably measured. In laboratory testing, Helium prevailed, with which in the vacuum method using a mass spectrometer these tightness requirements could be easily achieved. Other media, such as hydrogen or Methane, were not used in standard tests because of their hazard potential and detection limitation.
Particularly in performance tests, a practice-oriented medium has always been favored in sealing tests in the USA. Methane is the first choice as the smallest hydrocarbon molecule. In ASME B16.20, a new performance test has been introduced, in which the tightness requirement of spiral wound gaskets in a leakage test with Methane should be checked. And also in the valve test in ISO 15848-1, Methane is defined as an alternative test medium for Helium.
In this paper, the difference in the leakage test between Nitrogen, Helium and Methane in terms of handling, use in the test laboratory, the measurement of leakage rates and the detection limits between Nitrogen, Helium and Methane will be shown.
Evaluated Results of Seismic Design Approach Using Inelastic Dynamic Analysis for Equipment
Authors: Tamura Ichiro , Okubo Atsushi , Minakawa Yusuke , Iijima Tadashi , Namita Yoshio , Goshima Nobuyoshi , Amino Masanori , Okuda Yukihiko , Okuma Shunji 
Published: November 2019

Abstract
Securing adequate seismic safety margins has been important in safety reviews regarding the seismic design of equipment and piping systems in nuclear power plants, and there exists an increasing need for a more exact method for evaluating these margins. To this end, it is reasonable to take into account the reduction of seismic responses resulting from inelastic deformation. The authors studied this approach utilizing an elastic allowable limit in existing standard. The applicability of the proposed evaluation method was investigated by comparison with the conventional evaluation method. The proposed method consists of an inelastic dynamic analysis and an elastic-static analysis. The elastic-static analysis uses a load obtained from the inelastic dynamic analysis. For the investigation, the result obtained from the proposed method was compared with that obtained from the conventional elastic analysis to quantify the reduction in responses leading to seismic safety margins. For the comparison, the authors constructed three models that simulate a cantilever-type beam, four-legged tank, and core shroud and applied them to the analysis herein, and the applicability of our method was discussed for these models. In this paper, we present three topics. First, we present a scheme for developing the design approach of using inelastic analysis. Second, we report a sensitivity study of model parameters, such as yielding stress and second stiffness, done by analyzing the cantilever-type beam for the proposed method. Finally, we report the application of the method to the four-legged tank and core shroud.
Managing the Risks Associated With Operating a Hydrotreater Reactor With Possible High-Temperature Hydrogen Attack Damage
Authors: Prueter Phillip E. , Jones Ryan , Hess Jacki , DeLuca Joel 
Published: November 2019

Abstract
High-temperature hydrogen attack (HTHA) is a damage mechanism that can detrimentally affect the service life of carbon steel and low-chrome pressure equipment in the petroleum refining and related industries. HTHA involves the diffusion of hydrogen into steel, where it chemically reacts with free carbon at high temperatures to produce methane. This methane then gets trapped inside small cavities and other material defects. Over time, the rising methane pressure in these cavities can cause damage at the material grain boundaries. To this end, long-term exposure to high-temperature hydrogen environments can lead to volumetric damage that can diminish the load carrying capability of pressure equipment and accelerate the propagation of crack-like flaws. There have been several known industry failures attributed to HTHA damage as well.
This paper summarizes a case study of a detailed analytical evaluation of potential HTHA damage in a vintage C-0.5Mo hydrotreater reactor. The goal of this study is to quantify the severity of HTHA damage using methods developed as part of an ongoing, multi-year Joint Industry Project (JIP) to justify continued operation of the reactor until the earliest practical replacement opportunity. HTHA damage and crack growth predictions are carried out based on documented historical operating conditions. Additionally, sensitivity in predicted remaining life to anticipated future operating temperatures is considered. Furthermore, based on state-of-the-art non-destructive examination (NDE) methods, fracture mechanics-based minimum pressurization temperature (MPT) envelopes are generated to help guide start-up and shut-down procedures that mitigate the risk for brittle fracture. Practical recommendations are also provided to facilitate the interpretation of NDE findings and to implement on-going failure mitigation and risk management strategies, including the development of Integrity Operating Windows (IOWs), for the reactor until planned replacement.