bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of Safety Factors for Repair of Buried Nuclear Safety Related Metallic Pipe Using Carbon Fiber Reinforced Polymer
Authors: Marohl Michael P. H. , Ojdrovic Rasko 
Published: October 2018

Buried piping is subject to unique environmental exposure, loading, and restricted access once put into service. Buried piping is susceptible to various corrosion mechanisms on the outside of the pipe as well as internal corrosion mechanisms similar to other aboveground piping. Inspection, repair and replacement of buried piping to address such issues are inherently difficult and costly due to the access issues. To address such difficulties and avoid excavation, a carbon fiber reinforced polymer (CFRP) repair can be applied to the internal diameter of a buried pipe to provide a structural pressure boundary to strengthen or replace the existing piping over a specified length.
Pipe repairs using CFRP have traditionally been designed using a Load and Resistance Factor Design (LRFD) approach for determining the demand and the strength of the repair. However, inclusion of CFRP design rules into allowable stress design (ASD) based Section XI of the ASME Boiler and Pressure Vessel Code, which has not adopted LRFD, requires use of safety factors applied to the strength for the appropriate design rules. Both ASD and LRFD have the same philosophy that the stress from the applied loads must be less than the material strength by a certain factor, and the basic difference between the two approaches is how to determine the appropriate factor of safety to cover all unknown variations in load, material strength, installation, and other.
This paper provides a basis for development of safety factors for design of CFRP repairs of nuclear safety related buried metallic piping to meet the required maximum acceptable probability of failure and reliability in accordance with NEI 96-07.
Analyzing Accuracy, Repeatability, and Overall Performance of Torque Tools and Patterns on Multiple Flange Geometries
Authors: Hamilton Scott , Mahoney Dan , Wright Jason 
Published: October 2018

Many different variables need to be considered when a bolted flange is to be assembled. Past research on this topic has focused on nut factors, bolting patterns, gaskets, etc. However, there has been little research on the performance of torque as an assembly method.
The performance of various powered and manual torque wrenches is investigated, including accuracy (achieved bolt load versus target bolt load), repeatability (variation in achieved bolt load), and time to assemble. This study compared performance of seventeen different tools including pneumatic, hydraulic, and manual torque wrenches, across four different flange size/rating combinations utilizing two assembly method (Legacy Star and Modified Legacy Star).
This paper builds on the work described in PVP2017-65800 Determining Accuracy and Repeatability of Torque through Powered Equipment. A larger number of flange assemblies were performed compared to the PVP2017-65800 work, using a greater number of tools and flange configurations.
The results of the tests are provided and the implications of the findings discussed, including consideration of tool selection, assembly pattern selection, personnel competence and training, and bolted flange joint component selection and inspection.
Subsea Tree Connector Capacity Chart per the Elastic-Plastic Analysis Methodology
Authors: Sepehri Ali , Harbert Stuart , Wilhelmi Joe 
Published: October 2018

The oil and gas industry is currently drilling into and producing from wells in high-pressure, high-temperature (HPHT) environments. This has created a greater demand to develop more advanced tools and new technology to safely overcome the challenges in these operations. The Bureau of Safety and Environmental Enforcement (BSEE) requires equipment operating in HPHT environments to pass a design verification analysis. The design verification shall be evaluated using finite element analysis (FEA) per ASME Boiler Pressure Vessel Code (BPVC), Section VIII, Division 3 [1] and API 17TR8 [2].
The objective of this study is to generate a pressure-bending-tension (PBT) capacity chart per the elastic-plastic analysis methodology (global collapse criteria) outlined in KD-230 [1] for a subsea tree connector. The PBT capacity chart covers a wide range of normal operating conditions. Results indicate that the structural capacities from the elastic-plastic analysis methodology are higher than those determined by the standard elastic analysis methodology.
Code Case N-822 for Pin Brazing Non-Structural Attachment Tabs for Buried Pipe Cathodic Protection
Authors: McCracken Steven L. , Mohr Nick 
Published: October 2018

Cathodic protection (CP) is one of the primary methods to protect buried piping and pressure components from corrosion and is a critical element in asset management of buried piping at nuclear power plants. Implementation of cathodic protection requires non-structural attachments to the buried piping for electrical leads and connections. The method of attaching copper-copper alloy CP leads to carbon steel piping and components using traditional arc welding processes can be difficult and time consuming. A two-step process is frequently used where a carbon steel weld tab is first welded to the pipe or component by a traditional arc welding process. The copper-copper alloy CP lead is then joined to the carbon steel weld tab by the exothermic welding process.
An alternative to this cumbersome two-step process is pin brazing which is an automatic brazing process that uses electric current resistance to heat the interface between a pin capsule and the component. An arc between the pin capsule and the outside surface of the electrical connector is then used to melt the capsule or pin that contains the brazing filler metal. The process is similar to stud welding in that the brazing pin is loaded into an automatic pistol and the brazement is made when the trigger is pulled. ASME Section XI Code Case N-882 delineates rules and requirements for application of pin brazing on Class 2 and 3 pressure boundary components. This paper provides the background and description of the pin brazing process with a summary of the technical basis for Case N-882.
Trial Study of the Master Curve Fracture Toughness Evaluation by Mini-C(T) Specimens for Low Upper Shelf Weld Metal Linde-80
Authors: Yamamoto Masato 
Published: October 2018

The Master Curve (MC) method can be used to directly determine fracture toughness of ferritic reactor pressure vessel (RPV) materials. CRIEPI has been working on the development of a testing technique to apply very small C(T) (called Mini-C(T)) specimens for the MC method. The appropriateness of using Mini-C(T) specimens for several materials including un-irradiated plate, forging, weld metal and irradiated plate has been demonstrated. Through a series of investigations, it was determined that more invalid data, due to ductile crack growth (DCG), can occur when using small size specimens.
Linde-80 weld metal, used in the fabrication of some RPVs, is known as low upper shelf material, which tends to exhibit more DCG than high upper shelf materials. In the present study, two sets of 15 Mini-C(T) specimens were machined and pre-cracked from irradiated Linde-80 weld metal. Each set of specimens were provided to two different laboratories (A and B). The laboratories separately conducted the MC tests. DCG occurred even in the lower test temperature condition. About half of specimens for lab A showed excessive DCG and were subjected to the censoring. Some of specimens were rejected since the test temperature is outside of the specified range (T-To < −50°C). As a result, lab A could not obtain valid To with 15 specimens. Lab B also experienced DCG, however were able to obtain a sufficient number of valid KJc data points to determine a valid To. The obtained ToQ (lab A) and To (lab B) are sufficiently close to each other and suggests that Mini-C(T) can be used even for the low upper shelf material if the number of available specimens are sufficiently large. The combined dataset from labs A and B estimated To = 31.5°C, which is in the scatter band of To obtained by pre-cracked Chapry (PCCv), 0.5TC(T) or 1TC(T) specimens in a past Heavy-Section Steel Irradiation (HSSI) project. The overall result suggests that To can be estimated using Mini-C(T) specimens for the lower upper shelf weld material, but 15 is a marginal number of specimens for a valid estimation.
An Effect of Nozzle Flexibilities/Stiffness on Equipment Nozzle Loads and Local Stresses
Authors: Pathre Sujay S. , Govindan K. 
Published: October 2018

The loads on the equipment nozzles are generally generated by the piping stress engineer by doing the stress analysis of entire closed loop systems. Subsequently the nozzle loads are passed on to the engineers of the pressure vessel equipment. The value of the loads which have been worked out for the nozzle mostly depends upon the methods/concept by which the piping stress engineer has evaluated the piping loop. Nozzle flexibility/stiffness is the important parameter in evaluation of various components of nozzle loads. The objective of this paper is to explain the effect/influence of flexibility/stiffness generated from three different methods (Anchor, WRC and Finite element method) on nozzle load evaluation and shell/nozzle junction stresses.
WRC297 bulletin [6] gives the reference to nozzle flexibility in the appendix A, example no.3.
The work presented in this paper is an attempt to compare the nozzle loads calculated by evaluating the flexibilities/stiffness in various methods. Further an attempt has been made to consolidate the results of junction local stresses obtained by the various methods of stiffness/flexibilities which would result in realistic results and overall code acceptable stresses without the results being either overly conservative or unconservative.
Perspectives on Safety Margin Associated With Internal Repair of Buried Class 2 and 3 Safety Related Piping Using Carbon Fiber Reinforced Polymer Composites
Authors: Uddin M. F. , Krishnaswamy P. , Basavaraju C. , Manoly K. A. 
Published: October 2018

Carbon fiber reinforced polymer (CFRP) composites have been used for decades in various industries such as aerospace, oil and gas, and transportation mainly due to their high strength-to-weight-ratio and excellent corrosion resistance. However, the use of CFRP in nuclear industry applications has been very limited. Recently, a new ASME Boiler and Pressure Vessel (BPV) Code Case N-871 has been proposed for internal repair of buried Class 2 and 3 nuclear safety related piping using CFRP for Service Levels A, B, C and D at temperatures not exceeding 200F. This is a first-of-a-kind CFRP application for nuclear safety related piping.
It is known that CFRP materials are subject to property degradation due to environmental exposure as well as creep behavior under sustained loading. These factors should be considered when designing the CFRP repair for any nuclear safety related piping application to ensure an adequate safety margin is maintained. In the proposed Code Case, there are provisions for using two different design (analysis method) methods — Allowable Stress Design (ASD) and Load and Resistance Factor Design (LRFD) methods. The LRFD method has been widely used in civil engineering applications but has never been used in ASME Section III Code for nuclear piping applications. This paper presents a comparison of these two methods from a safety margin point of view. As CFRP is a new material for ASME BPV Code for nuclear safety related applications, several areas have been identified in the design concepts to ensure an adequate safety margin for Service Levels A, B, C and D. An effort is also made to provide guidelines on the required safety margin for CFRP repair of safety related piping. Finally, Code Case N-871 is reviewed to evaluate the minimum safety margin available for both ASD and LRFD methods.
A General Comparison of the Design Margins and Design Rules for ASME Section VIII, Divisions 1 and 2
Authors: Barkley Nathan 
Published: October 2018

Beginning with the 2017 Edition of the ASME Boiler and Pressure Vessel Code, vessels designed according to the rules of Section VIII, Division 2 shall be designated as either Class 1 or Class 2. One of the key differences between Class 1 and Class 2 is the applicable Design Margin of 3.0 and 2.4 against the Ultimate Tensile Strength of the material, respectively. Vessels designed in accordance to Section VIII, Division 1 have a Design Margin of 3.5 against the Ultimate Tensile Strength of the material. Code Case 2695 allows the vessel designer to utilize the design rules of Section VIII, Division 2 for a Section VIII, Division 1 vessel while maintaining the tensile strength Design Margin of 3.5. However, Design Margins against the Ultimate Tensile Strength of the material are not the only applicable margins that must be considered.
This paper reviews the procedure for deriving the allowable stresses of materials under tensile loading based on the required Design Margins for each Division and Class with some historical background provided. Discussion and comparisons of some of the relevant differences between the design rules of Section VIII, Division 1 and 2 and how the differing Design Margins affect the component design is presented. Carbon Steel with joint efficiencies of 1.0 are used for simplicity.
Hybrid Welding: Investigation of the Induced Residual Stresses
Authors: Gallee Sébastien , Robin Vincent , Gommez Florence , Jourden Erwan , Lacroix Rémi 
Published: October 2018

The present paper deals with the hybrid laser/MIG welding process, which allows to join high thickness steel sheets. The laser heat source added to the MIG torch improves the process productivity while respecting quality standard.
The multi-pass welding simulation of a plate is presented in this paper and numerical results are compared to experimental measurements (temperature and stresses).
Creep Deformation Analyses for Grade 91 Steels Considering Heat-to-Heat Variation
Authors: Shigeyama Haruhisa , Takahashi Yukio , Siefert John , Parker Jonathan 
Published: October 2018

In order to evaluate creep life of heat-resistant materials used in power plants, it is important to estimate variation of stress distribution caused by creep deformation appropriately. For achieving this, creep strain equations which can express the creep deformation behavior with good accuracy are indispensable. Additionally, a lot of heat-resistant steels show large heat-to-heat variations in creep properties. Therefore, it is also important to take into account of the heat-to-heat variations in the creep analyses.
In this study, existing creep strain equations for Grade 91 steel were applied to six heats with a variety of creep strength and creep deformation behavior. Furthermore, some modification was made in order to obtain better agreement with test data in primary creep stage. It was found that reasonable agreements were obtained between the measured creep deformation behavior and predictions obtained by these equations only by changing creep rupture property depending on the particular heats. This suggests that reasonable prediction for creep deformation can be made even for the materials lacking the information of creep deformation as long as their rupture properties are known.
Strain Capacity Investigation on Grade X70 High Strain Line Pipe With Girth Weld
Authors: Tajika Hisakazu , Sakimoto Takahiro , Handa Tsunehisa , Igi Satoshi , Ikeda Rinsei , Kondo Joe 
Published: October 2018

Recently high grade pipeline project have been planned in hostile environment like landslide in mountain area, liquefaction in reclaimed land or the frost heave in Polar Regions. Geohazards bring large scale ground deformation and effect on the varied pipeline to cause large deformation. Therefore, strain capacity is important for the pipeline and strain based design is also needed to keep gas transportation project in safe. High grade steel pipe for linepipe tends to have higher yield to tensile (Y/T) ratio and it has been investigated that the lower Y/T ratio of the material improves strain capacity in buckling and tensile limit state. In onshore pipeline project, pipe usually transported in 12 or 18m each and jointed in the field. Girth weld (GW) is indispensable so strength matching of girth weld towards pipe body is important.
In this study strain capacity of Grade X70 high strain pipe with size of 36” OD and 23mm WT was investigated with two types of experiments. One was a pipe bending test with whole pipe. The length of the specimen was approximately 8m and GW was made in the middle of joint length. A fixed internal pressure was applied during the bending test. Actual pipe situation in work was simulated and both circumferential and longitudinal stress occurred in this test.
The other test was curved wide plate (CWP) test. In both tests, test pipes were cut and welded using GTAW in the first two layers and GMAW for the subsequent passes. Welding wire of TG-S62 and MG-S58P were used for GTAW and GMAW respectively to achieve over-matching girth weld considering the pipe body strength. Elliptical EDM notch was installed in the GW HAZ as simulated weld defect.
In pipe bending test, buckling occurred at the intrados at 300 mm apart from the GW. 2D average compressive strain at buckling was 3.59% and this high compressive strain was considered to derive from the high strain capacity of this pipes. After the buckling, deformation concentrated to the buckling wrinkle. Test pipe broke at 35.5 degrees of pipe end rotation and the location was in base metal at the extrados opposite to the buckling wrinkle. The HAZ notch opened and CTOD was 1.44 mm and the global strain in 2D length average strain was 7.8%.
In CWP test, tensile strain simply got large and pipe finally broke at global strain of 9.6% and CTOD of 15 mm. The break location was the HAZ notch. There was a significant difference in CTOD growth in HAZ between two test types. Conditions and factors that effect to these differences are argued in this paper.
Evaluation of Fatigue Design Curves for a Double-Side Welded Connection Used in Offshore Applications
Authors: Correia José A. F. O. , Correia Miguel , Holm Mads , Ekeborg Julle , Lesiuk Grzegorz , Castro José M. , de Jesus Abílio M. P. , Calçada Rui 
Published: October 2018

One of the major concerns in offshore structures are the welded connections where fatigue failures are highly relevant. In many cases of offshore welded connections, the fatigue cracks initiated may grow from the weld to the base material, but also from the root of the weld.
In this study, the evaluation of design S-N curves for a double-side welded connection made of S355J2 steel used in offshore applications is proposed. The characteristic fatigue curve of the double-side welded connection is obtained using statistical analyses based either in the ASTM E739 standard as well as the probabilistic fatigue model proposed by Castillo & Fernández-Canteli. This study concludes with a comparison between the experimental fatigue curves obtained and the design S-N curves proposed in design codes for offshore structures. Existing code recommendations are very conservative when comparing the design S-N curves with the proposed new characteristic S-N curves. For the joint under investigation the hot spot and nominal stress approaches yield very similar S-N results.
Why has adolescent smoking declined dramatically? Trend analysis using repeat cross-sectional data from New Zealand 2002–2015
Authors: Ball Jude , Sim Dalice , Edwards Richard 
Published: October 2018

ObjectivesAdolescent smoking has declined in New Zealand and in many other countries since the late 1990s, yet the reasons for the decline are not well understood. We investigated the extent to which established risk factors for adolescent smoking (parental, sibling and peer smoking, and exposure to smoking in the home) explained the downward trend.DesignTrend analysis of repeat cross-sectional data from an annual nationally representative survey.SettingNew Zealand.ParticipantsSecondary school students aged 14–15 (n=398 221).Outcome measureRegular (at least monthly) smoking.MethodsFor each risk factor (parental smoking, best friend smoking, older sibling smoking and past week exposure to smoking in the home) we plotted prevalence of exposure, 2002–2015. Next, using multivariable logistic regression, we modelled the trend in regular smoking (expressed as an OR for year) adjusting for age, sex, ethnicity and socioeconomic position. The risk factors were added to the model—individually and collectively—to test whether they attenuated the OR for year.ResultsExposure to all risk factors except ‘past week exposure to smoking in the home’ decreased between 2002 and 2015. We observed a strong downward trend in regular smoking among adolescents (OR=0.88 per year, 95% CI 0.88 to 0.88, p<0.001). ‘Best friend smoking’ was the only risk factor that significantly attenuated the trend. However, due to circularity, this factor provides an unsatisfactory explanation for population level smoking decline.ConclusionsThe established risk factors that we explored do not appear to have contributed to the remarkable decline in adolescent smoking in New Zealand between 2003 and 2015. Further research is needed to assess the possible contribution of factors outside our model, such as changes in the policy context, the social meaning of smoking and broader social and economic conditions.
Determination of venlafaxine and its active metabolite O-desmethylvenlafaxine in human plasma by HPLC fluorescence
Authors: Shen Shujuan , Zhang Chen , Mao Yemeng 
Published: October 2018

BackgroundTherapeutic drug monitoring guides clinical individualised medication by measuring plasma concentration, which could improve the curative effect, avoid drug overdose and reduce the incidence of adverse reactions. At present, there are few reports on the clinical detection of venlafaxine and its active metabolite O-desmethylvenlafaxine. In this paper, the detection method of venlafaxine and O-desmethylvenlafaxine in blood plasma was established, which provides an effective and convenient means for guiding clinical application of medication.AimTo establish a method for determination of venlafaxine and its active metabolite O-desmethylvenlafaxine in human plasma by high-performance liquid chromatography with fluorescence detection.MethodsChromatographic separation was achieved on an Agilent Eclipse XDB-C18 Column (4.6 × 150 mm, 5 µm) with water containing sodium dihydrogen phosphate (0.05 mol/L) and acetonitrile (72:28) as the mobile phases. The following parameters were employed: flow rate 0.5 mL/min, column temperature 30°C, fluorescence excitation wavelength 276 nm and emission wavelength 598 nm.ResultsThe method showed good linearity in the concentration range 10–1000 ng/mL. The regression equation for venlafaxine was R=0.0054C+0.0264, r2=0.99991. The regression equation for O-desmethylvenlafaxine was R=0.0034C+0.0272, r2=0.99969. The intraday and interday precisions (relative SD) were less than 10%, and the quantitative limit was 10 ng/mL.ConclusionWe established a sensitive, specific and simple method for the detection of venlafaxine and O-desmethylvenlafaxine. This method fully meets the needs of clinical trials of venlafaxine and the requirements of relevant guidelines. It provided a reference for the clinical detection of venlafaxine and O-desmethylvenlafaxine plasma concentrations and pharmacokinetic study.