bluuebunny/crossref_metadata_2025_split huggingface dataset:
Failure Analysis of Flange Sealing Surface of Outlet Pipeline of Wax Oil Hydrogenation Reactor
Authors: Shi Jiqing , Wang Jielu , Song Wenming , Huang Chaopeng 
Published: October 2020

Abstract
Hydrogenation reactor is the core equipment of various hydrogenation units or hydrogenation processes. Because of the harsh service environment, the difficult manufacturing technology, the high requirements and the expensive cost, the safety of hydrogenation reactor is a very important problem. The outlet flange of hydrogenation reactor in a petrochemical company suddenly cracked after several years of use. The maximum depth of the crack from the sealing surface to the depth of the flange is 165 mm, the circumferential cracking range is about 130 degrees. The crack is in a circumferential and curved line along the sealing groove, and has small bifurcations at the tip. In order to ensure the safety of equipment operation and prevent the recurrence of this kind of accident, the causes of flange failure were systematically analyzed and the preventive measures are formulated. This paper reviewed the manufacturing quality data of the failed flange, and carried out a series of tests and analyses, such as macroscopic inspection, penetration testing, ultrasonic testing, mechanical properties test, chemical composition analysis, metallographic structure analysis, finite element stress check and so on. Combined with the use environment and the operation parameters of the flange, we preliminarily analyze that the cause of flange cracking may be manufacturing defects. In order to avoid the failure of flanges again, it is recommended that the flanges of the same batch should be tested one by one to ensure the safe and stable operation of the device.
Throttling Effect and Thermodynamic Characteristics of Supercritical CO2 Flowing Through Shut-Off Valve
Authors: Guo Xiaolu , Xu Peng , Xu Shuangqing 
Published: October 2020

Abstract
The supercritical flow of CO2 is widely applied in energy fields such as the carbon capture and storage technology and the Brayton cycle power generation technology. The shut-off valves are widely used in various systems of energy fields, and their use is related to the stability and safety of the system. Due to the throttling effect of supercritical CO2 flowing through the valve, the large temperature drop may cause the dry ice generation, the overpressure and the blockage, which have an important impact on the safety and stability of the whole system. At present, there are few researches on the throttling effect and thermodynamic characteristics of supercritical CO2 flowing through the shut-off valve. In this paper, the pressure and temperature changes before the valve inlet and after the valve outlet were studied, and the field of pressure, temperature and phase inside the valve were analyzed. It was found that the outlet pressure of the shut-off valve increased rapidly after the valve was opened, and the temperature decreased at the same time. With the decrease of system pressure, supercritical CO2 in front of the valve changed into gas-liquid two-phase and gas-phase successively, and CO2 after the valve changed into gas-phase, liquid-phase, gas-liquid two-phase and gas-phase successively. This study is of great significance to the stability and safe operation of energy systems.
Research and Development of Viscous Fluid Dampers for Improvement of Seismic Resistance of Thermal Power Plants: Part 10 — Damper to Suppress Relative Deformation Between Furnace and Cage
Authors: Minagawa Keisuke , Aida Kiyoshi , Fujita Satoshi 
Published: October 2020

Abstract
In Hokkaido Eastern Iburi Earthquake in 2018, strong ground motion attacked a coal-fired thermal plant. A connecting part of a furnace and a cage of a boiler in the power plant and steam tubes in that part were damaged. Consequently the damage of the power plant induced a large impact to society. Suppressing relative displacement between the furnace and the cage might be effective to reduce this kind of the damage, because the furnace and the cage vibrate independently during earthquakes. Therefore this paper proposes application of dampers to the connecting part of the furnace and the cage of the boiler based on the results of the Part 9. The dampers are installed horizontally between the furnace and the cage and suppress relative displacement. The length and shape of the furnace are different from the cage, thus amount of the thermal expansion is also different. Therefore the damper has to allow the difference of the amount of the thermal expansion. In addition, the damper has to generate large damping force from the small vibration. Thus a viscous damper with high viscosity fluid is applied as a damper which satisfies above-mentioned requirements. A seismic response analysis using a frame model was conducted in order to verify the effect of the damper and to investigate the influence of the damping capacity of the damper. As a results, it was confirmed that the relative displacement between the furnace and the cage can be suppressed by applying the damper.
Effect of High-Pressure Hydrogen and Water Impurity on Aluminum Alloys
Authors: San Marchi Chris , Schwarz Martina , Ronevich Joseph 
Published: October 2020

Abstract
Aluminum alloys are desirable in mobile fuel cell applications due to the combination of strength, hydrogen resistance, and low density. In dry hydrogen environments, the fatigue and fracture resistance of common structural aluminum alloys are not degraded compared to air environments. However, aluminum alloys can be susceptible to stress corrosion cracking in humid air, which raises questions about the potential deleterious effects of moisture impurities in high-pressure hydrogen environments. While this study does not address the effects of the air environment on aluminum hydrogen pressure components, we assess the fracture resistance of aluminum alloys in high-pressure hydrogen containing known amount of water. High-pressure gaseous hydrogen at pressure up to 100 MPa is shown to have no effect on elastic-plastic fracture measurements of common high-strength aluminum alloys in tempers designed for resistance to stress corrosion cracking. Complementary sustained load cracking tests in high-pressure hydrogen were also performed in gaseous hydrogen at pressure of approximately 100 MPa with water content near the maximum allowed in hydrogen standards for fuel cell vehicles. These tests show no evidence of environmental-assisted cracking at loading conditions approaching the onset of unstable fracture in this configuration. In summary, typical moisture content in fuel cell grade hydrogen (&lt; 5 ppm) do not promote hydrogen-assisted fracture or stress corrosion cracking in the tested aluminum alloys.
An Overview of ASME Section III Class 2 and 3 Valve Design and Service Loading Rules
Authors: Farrell Ronald , Lambin Jason 
Published: October 2020

Abstract
In addition to providing an overview of the ASME Boiler and Pressure Vessel Code design rules applicable to Class 2 and 3 valves, where Class is defined in Section III of the ASME Code, Sub-Article NCA-2130, this paper offers some insight as to why the rules are as they are. The motivation comes from a request by the ASME Codes and Standards Committee, Components Subgroup, for the Valve Working Group to prepare this overview. The request came after discussing a question from a participant regarding how the “(Primary Membrane or Local) plus Bending” stress category should be addressed for a valve.
The paper goes beyond a basic overview of Code rules as it includes a discussion of the underlying valve standard ASME B16.34, looks at the valve rules in relation with the rest of the Code, and contributes some historical perspective. From a perusal of the Code both in general and during preparation of this paper, it is concluded that the valve Code rules could benefit from a few clarifications; thus, changes are proposed, and the Working Group is encouraged to consider them. In answer to the underlying question regarding the primary local stress category, it is shown that the need for a local stress evaluation would be rare for a valve.
Plasma Arc Welding for Code Compliance Nuclear Applications
Authors: Sun Dongmei (Donna) , Pistor Rob 
Published: October 2020

Abstract
Plasma Arc Welding (PAW) has been used for many critical applications due to its flexibility, reliability and high weld quality. In this paper, two code compliance plasma arc welding applications in the nuclear industry are discussed.
The first application is an innovative welding process using PAW with specially designed dual hot wire feeding system, namely Dual Hot Wire Gas Metal Plasma Arc Welding (GMPAW). The GMPAW process offers unique advantages for high deposition and low dilution weld overlay application. The second application is a remote weld overlay repair from pipe inside diameter (ID) for a highly radiated nuclear component using PAW process with remote machining and NDE capability.
In this paper, the benefits and advantages are provided for the aforementioned PAW applications. The versatility of plasma arc welding system configuration, as well as high quality and productivity can make plasma arc welding a good candidate for many critical code compliance applications.
Microstructural Evolution During a Solid State Tube Pinch Weld
Authors: Korinko Paul S. 
Published: October 2020

Abstract
Microstructure development is examined for a specialized spot weld that is used as a solid-state closure process for stainless steel tubing, referred to as pinch welding. In order to elucidate the microstructural evolution of the weld, a series of test welds were made at nominal conditions using both tubes, used in test articles and production like components. These pinch welds normally terminate after twelve cycles of a 60 Hz AC weld process. In this study, tubes with different thermal processing history were welded from one to twelve cycles and the microstructure and weld variables after each individual weld cycle number were characterized using radiography and optical metallography. Two etchants were used that highlighted different microstructural features. The study revealed that: (1) this type pinch weld is largely complete after about six cycles of 60 Hz AC current, half the weld time utilized; (2) the resistance, deformation, and closure length approach “steady state” conditions after six cycles; and (3) both oxalic and nitric acid electrolytic etchants are useful for highlighting specific microstructural attributes of type 304L stainless steel. Finally, two distinct microstructural regions can be identified for these welds: the edge of the weld which is driven by concentrated deformation, recrystallization and grain growth and the center region which is more typical of forge welding and micro-asperity breakdown followed by diffusion and grain-growth. The bond line of annealed tubes exhibits fewer indications and less contamination than that of the partially annealed and as-received cold worked tubes.
Increasing Fatigue Strength and Wear Resistance of Additive Manufactured Nickel Alloy (UNS N07718) by Ultrasonic Nanocrystal Surface Modification (UNSM) Treatment
Authors: Pyun Young Sik , Choi Seimi , Karimbaev Ruslan , Ro Jun Suek , Sanseong Choong Ho , Sembiring Jan , Kim Jong Seog , Amanov Auezhan , Kang Suk Hoon , Ahn Hee Sung 
Published: October 2020

Abstract
Additive Manufacturing (AM) which is also known as metal 3D printing technique is a promising process with a massive potential for developing a component for wide range applications for various industries. Recently, AM process was introduced to the nuclear power plant industry as AM is capable of manufacturing the substitution of aging and obsolete component. However, the AM component has inferior mechanical properties and performance in terms of fatigue strength and wear resistance compared to its conventionally manufactured counterpart. Ultrasonic Nanocrystal Surface Modification (UNSM) is one of mechanical surface modification treatment known for improving fatigue strength and wear resistance of wrought material. Hence, in this study effect of UNSM treatment on fatigue strength and wear resistance of additive manufactured material was investigated. The investigation was done to Ni-based alloy 718 (UNS N07718) as this material is used for nuclear power plant components and was manufactured with two different AM techniques namely Powder Bed Fusion (PBF) and Direct Energy Deposition (DED) processes. The evaluation was conducted by comparing the as-polished and UNSM-treated specimens for each AM processes by performing fatigue and tribo tests. This result will become a part of the technical basis for KEPIC Code Case development.
Environmental Fatigue Analysis Considering Thermal Stratification in Direct Vessel Injection Piping
Authors: Lee Bonghee , Nam Ilkwun , Park Sangyun , Kim Sookyum , Kim Yongbaek 
Published: October 2020

Abstract
Thermal stratification-induced stresses could lead to a serious failure and fatigue crack on piping systems. U.S. NRC Bulletin 88-08 [1] requires to investigate which unisolable pipings are subjected to the thermal stratification and to demonstrate compliance with applicable code limits during the piping design stage by incorporating the thermal stratification-induced stresses into the fatigue evaluation.
In this paper, the computational fluid dynamic (CFD) analyses considering both the out-leakage case by turbulent penetration and the in-leakage case by valve leakage were performed for the unisolable portion of the Direct Vessel Injection (DVI) piping between the reactor vessel nozzle and the first check valve to determine the change of temperature gradient on the pipe wall as a function of time due to the thermal stratification. And then the CFD-based temperature distributions on the pipe wall at each time interval were transformed as input data for the structural analysis to evaluate the stresses induced by the global bending moments and local stresses by the thermal stratification of the DVI piping.
The localized thermal stratification stress intensities were directly extracted from the 3-D model using the ANSYS program and were categorized as the three stress terms induced by ΔT1, ΔT2, and Ta - Tb defined in NB-3600 of ASME B&PV Sec. III [2], but including thermal stratification effects herein for the fatigue analysis. To evaluate the air environment- and LWR environment-based fatigue damages for the DVI piping, the bending moments and three local stress terms due to the thermal stratification were incorporated into the fatigue analysis. NB-3200/-3600 of ASME B&PV Sec. III- and Regulatory Guide 1.207-based cumulative usage factors [3, 4] were compared with each other to investigate the effects of fatigue damages considering the thermal stratification in the air and light water reactor (LWR) environments.
Properties of Cladding With Respect to RPV Integrity
Authors: Brumovský Milan 
Published: October 2020

Abstract
Inner surface of most of primary circuit components in PWR/BWR/WWER type reactors is covered by austenitic cladding that serves primarily as anticorrosion protection. This is also supported by the requirements for stress analysis of the vessel by most of the codes — austenitic cladding is not taken into account in the calculation of vessel wall thickness and on allowance of stress intensities for operating conditions. Its effect is taken, in some codes like for WWER components, in fatigue calculation and also for evaluation of vessel resistance against fast fracture during pressurized thermal shock (PTS) events.
Vibration of FRP Bypass Piping of Sea Water Intake System in Offshore Platform
Authors: Choi Capjoo , Chu Yeon-Young 
Published: October 2020

Abstract
Severe vibration is observed at FRP (Glass-Fiber-Reinforced Thermosetting-Resin) bypass line connected to discharge of sea water intake pump which is installed on offshore platform. To find out characteristic of the flow, CFD (Computational fluid dynamics) analysis is conducted, and result shows that it is produced by complex pulsating two phase flow formed by the high speed water jet at the resistance orifice which passes through several elbows. After CFD analysis, the force-time history result from CFD analysis is used in transient structural analysis. Based on the numerical analysis result, mechanical response of the pipe and structure for the initial piping system and reinforced piping system are verified and compared with criteria of Energy Institute guideline and NORSOK S-002. Also in order to demonstrate a validity of the numerical analysis and check soundness of the whole reinforced piping and structure system with vibration, site measurement is performed. Moreover, in order to check the stress level of piping, dynamic strain measurement is undertaken.
This paper discusses the details on history of bypass line design to avoid air entrapment not to damage on seawater pump, and how the vibration issue is approached, and finally compared with industry standard for safety. Further, the paper presents the numerical analysis result that makes design modifications implement for bypass piping and structure during a commissioning, and various evaluation method that verify the soundness of piping and structure based on field vibration measurement.
Crack Opening Areas Under Combined Primary and Secondary Loading
Authors: Brayshaw W. J. , James P. , Sharples J. , Aird C. 
Published: October 2020

Abstract
Leak-before-break is a methodology to assess whether a leak through a defect in a pressurised component can be detected prior to the defect attaining a critical size. Developing leak-before-break arguments in non-stress relieved piping components can be challenging, in part due to the lack of solutions available, including in R6, to predict the crack opening area (required to evaluate leak rate) for combined primary and secondary stresses under elastic-plastic conditions. This is because the nature of the secondary stresses is to relax with plasticity, which can be captured in the calculation of the crack driving force (elastic-plastic stress intensity factor), but methods to account for the additional crack-tip strain this induces and its influence on crack opening are not available. Here primary stresses are those resulting from an applied force, such as pressure, and secondary stresses are those which result from an internal mismatch and do not contribute to plastic collapse, such as thermal or residual stresses. There is, of course, potential for a higher accuracy of crack opening area evaluations from finite element analysis modelling approaches, which include elastic-plastic material properties, in the presence of combined loading scenarios.
In this study, a series of finite element analyses have been conducted whereby crack opening area and stress intensity factor have been calculated from circumferential through-wall defects, under the influence of combined primary and secondary stresses, where the magnitude and order of the combined stress has also been varied. The crack opening areas have been compared to current elastic ‘handbook’ solutions, which are conservative for primary stresses, to better understand the effect of plasticity on crack opening area and to help inform assessments when accounting for the inclusion of plasticity with secondary stresses.
Numerical and Experimental Residual Stresses of Different Welded Joint Configurations in Heavy Wall
Authors: Colombo Chiara , Monti Stefano , Guagliano Mario , Vergani Laura , Fiordaligi Emanuele , Fusari Fausto 
Published: October 2020

Abstract
Refinery equipment subjected to high pressure is commonly made of Vanadium high strength steels (2¼Cr1Mo¼V), characterized by high allowable stress and low toughness in the as welded condition, leading to potential wall cracking before the application of thermal treatments. Therefore, the decision to perform specific thermal treatments after welding is of paramount importance. These thermal treatments, which are quite expensive and time demanding for the manufacturer, are still under discussion and not supported by evident scientific findings. The paper presents a numerical and experimental study on a plate-to-plate weld and on a nozzle-to-plate weld, created as ad-hoc mock-ups. Experimental residual stresses are collected by an X-ray diffractometer in the as welded configurations. These values are used to validate a complex 3D numerical model, implemented with the finite element software Abaqus and its AWI plugin. Finally, this validated model allows for the identification of joint criticality through two parameters: the volume of plasticized material per unit of welded length and the strain-based assessment according with ASME code. Their application as tools to compare the criticality of different welded geometries and the effect of thermal treatments on the residual stress field are discussed.
Study of the Influence of Microstructure and Intergranular Carbides on the Oxidation Behavior of a Nickel Base Alloy 690 TT in Supercritical Water Nuclear Reactor Conditions
Authors: Sáez-Maderuelo Alberto , Ruiz-Lorenzo María Luisa , Perosanz Francisco Javier , Halodová Patricie , Prochazka Jan , Namburi Hygreeva 
Published: October 2020

Abstract
Alloy 690, which was designed as a replacement for the Alloy 600, is widely used in the nuclear industry due to its optimum behavior to stress corrosion cracking (SCC) under nuclear reactor operating conditions. Because of this superior resistance, alloy 690 has been proposed as a candidate structural material for the Supercritical Water Reactor (SCWR), which is one of the designs of the next generation of nuclear power plants (Gen IV).
In spite of this, striking results were found [1] when alloy 690 was tested without intergranular carbides. These results showed that, contrary to expectations, the crack growth rate is lower in samples without intergranular carbides than in samples with intergranular carbides. Therefore, the role of the carbides in the corrosion behavior of Alloy 690 is not yet well understood.
Considering these observations, the aim of this work is to study the effect of intergranular carbides in the oxidation behavior (as a preliminary stage of degenerative processes SCC) of Alloy 690 in supercritical water (SCW) at two temperatures: 400 °C and 500 °C and 25 MPa. Oxide layers of selected specimens were studied by different techniques like Scanning Electron Microscope (SEM) and Auger Electron Spectroscopy (AES).
Assessment of Compact Heat Exchanger Design According to the Simplified ASME Analysis Methodologies
Authors: Shaw Avinash , Jentz Ian W. , Mahajan Heramb P. , Hassan Tasnim 
Published: October 2020

Abstract
High thermal efficiency of Compact Heat Exchangers (CHX) makes them distinctly utile for application to Next Generation Nuclear Plants (NGNPs). The high temperature application and transient conditions of NGNP operation induce stresses in CHX. These induced stresses can be categorized under different classifications based on their cause and location. ASME Sec. III Div. 5 has different analysis methodologies based on failure modes, failure criteria to be assessed, and constitutive relationship considered. The primary objective of this study is to provide a description of the classification of stresses in CHX. Further, evaluation of CHX design is conducted according to simplified analysis methodologies in ASME Sec. III Div. 5: Elastic and Simplified Inelastic Analysis. These simplified analyses are performed following the submodeling technique. At the global level, the channeled core is replaced by an elastic orthotropic core for analysis. At the local level, the stresses and strains for critical regions are determined following the simplified analysis methods. The load controlled stresses are checked against HBB-3220 of ASME Sec. III Div. 5. For the Elastic Analysis Method, strains in critical sections in CHX are checked for thermomechanical cycle against the HBB-T-1320 of ASME Sec. III Div. 5 criteria. For Simplified Inelastic Analysis, critical sections are analyzed for strain limits following HBB-T-1330 of ASME Sec. III Div. 5. The analyses outcomes are compared and results are discussed.