WorldWideScience

Sample records for composite pressure vessels

  1. NDE and Stress Monitoring on Composite Overwrapped Pressure Vessels Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Damage caused by composite overwrapped pressure vessels (COPVs) failure can be catastrophic. Thus, monitoring condition and stress in the composite overwrap,...

  2. Titanium Matrix Composite Pressure Vessel Project

    Data.gov (United States)

    National Aeronautics and Space Administration — For over 15 years, FMW Composite Systems has developed Metal Matrix Composite manufacturing methodologies for fabricating silicon-carbide-fiber-reinforced titanium...

  3. Reliability Considerations for Composite Overwrapped Pressure Vessels on Spacecraft

    Science.gov (United States)

    Murthy, Pappu L. N.; Gyekenyesi, John P.; Grimes-Ledesma, Lorie; Phoenix, S. L.

    2007-01-01

    Composite Overwrapped Pressure Vessels (COPVs) are used to store gases under high pressure onboard spacecraft. These are used for a variety of purposes such as propelling liquid fuel etc, Kevlar, glass, Carbon and other more recent fibers have all been in use to overwrap the vessels. COPVs usually have a thin metallic liner with the primary purpose of containing the gases and prevent any leakage. The liner is overwrapped with filament wound composite such as Kevlar, Carbon or Glass fiber. Although the liner is required to perform in the leak before break mode making the failure a relatively benign mode, the overwrap can fail catastrophically under sustained load due to stress rupture. It is this failure mode that is of major concern as the stored energy of such vessels is often great enough ta cause loss of crew and vehicle. The present paper addresses some of the reliability concerns associated specifically with Kevlar Composite Overwrapped Pressure Vessels. The primary focus of the paper is on how reliability of COPV's are established for the purpose of deciding in general their flight worthiness and continued use. Analytical models based on existing design data will be presented showing how to achieve the required reliability metric to the end of a specific period of performance. Uncertainties in the design parameters and how they affect reliability and confidence intervals will be addressed as well. Some trade studies showing how reliability changes with time during a program period will be presented.

  4. Composite Overwrapped Pressure Vessels (COPV) Materials Aging Issues

    Science.gov (United States)

    2010-01-01

    This slide presentation reviews some of the issues concerning the aging of the materials in a Composite Overwrapped Pressure Vessels (COPV). The basic composition of the COPV is a Boss, a composite overwrap, and a metallic liner. The lifetime of a COPV is affected by the age of the overwrap, the cyclic fatigue of the metallic liner, and stress rupture life, a sudden and catastrophic failure of the overwrap while holding at a stress level below the ultimate strength for an extended time. There is information about the coupon tests that were performed, and a test on a flight COPV.

  5. Composite Pressure Vessel Variability in Geometry and Filament Winding Model

    Science.gov (United States)

    Green, Steven J.; Greene, Nathanael J.

    2012-01-01

    Composite pressure vessels (CPVs) are used in a variety of applications ranging from carbon dioxide canisters for paintball guns to life support and pressurant storage on the International Space Station. With widespread use, it is important to be able to evaluate the effect of variability on structural performance. Data analysis was completed on CPVs to determine the amount of variation that occurs among the same type of CPV, and a filament winding routine was developed to facilitate study of the effect of manufacturing variation on structural response.

  6. Stress Rupture Life Reliability Measures for Composite Overwrapped Pressure Vessels

    Science.gov (United States)

    Murthy, Pappu L. N.; Thesken, John C.; Phoenix, S. Leigh; Grimes-Ledesma, Lorie

    2007-01-01

    Composite Overwrapped Pressure Vessels (COPVs) are often used for storing pressurant gases onboard spacecraft. Kevlar (DuPont), glass, carbon and other more recent fibers have all been used as overwraps. Due to the fact that overwraps are subjected to sustained loads for an extended period during a mission, stress rupture failure is a major concern. It is therefore important to ascertain the reliability of these vessels by analysis, since the testing of each flight design cannot be completed on a practical time scale. The present paper examines specifically a Weibull statistics based stress rupture model and considers the various uncertainties associated with the model parameters. The paper also examines several reliability estimate measures that would be of use for the purpose of recertification and for qualifying flight worthiness of these vessels. Specifically, deterministic values for a point estimate, mean estimate and 90/95 percent confidence estimates of the reliability are all examined for a typical flight quality vessel under constant stress. The mean and the 90/95 percent confidence estimates are computed using Monte-Carlo simulation techniques by assuming distribution statistics of model parameters based also on simulation and on the available data, especially the sample sizes represented in the data. The data for the stress rupture model are obtained from the Lawrence Livermore National Laboratories (LLNL) stress rupture testing program, carried out for the past 35 years. Deterministic as well as probabilistic sensitivities are examined.

  7. Composite Overwrap Pressure Vessels: Mechanics and Stress Rupture Lifting Philosophy

    Science.gov (United States)

    Thesken, John C.; Murthy, Pappu L. N.; Phoenix, S. L.

    2009-01-01

    The NASA Engineering and Safety Center (NESC) has been conducting an independent technical assessment to address safety concerns related to the known stress rupture failure mode of filament wound pressure vessels in use on Shuttle and the International Space Station. The Shuttle s Kevlar-49 (DuPont) fiber overwrapped tanks are of particular concern due to their long usage and the poorly understood stress rupture process in Kevlar-49 filaments. Existing long term data show that the rupture process is a function of stress, temperature and time. However due to the presence of load sharing liners and the complex manufacturing procedures, the state of actual fiber stress in flight hardware and test articles is not clearly known. Indeed nonconservative life predictions have been made where stress rupture data and lifing procedures have ignored the contribution of the liner in favor of applied pressure as the controlling load parameter. With the aid of analytical and finite element results, this paper examines the fundamental mechanical response of composite overwrapped pressure vessels including the influence of elastic plastic liners and degraded/creeping overwrap properties. Graphical methods are presented describing the non-linear relationship of applied pressure to Kevlar-49 fiber stress/strain during manufacturing, operations and burst loadings. These are applied to experimental measurements made on a variety of vessel systems to demonstrate the correct calibration of fiber stress as a function of pressure. Applying this analysis to the actual qualification burst data for Shuttle flight hardware revealed that the nominal fiber stress at burst was in some cases 23 percent lower than what had previously been used to predict stress rupture life. These results motivate a detailed discussion of the appropriate stress rupture lifing philosophy for COPVs including the correct transference of stress rupture life data between dissimilar vessels and test articles.

  8. Composite Overwrap Pressure Vessels: Mechanics and Stress Rupture Lifing Philosophy

    Science.gov (United States)

    Thesken, John C.; Murthy, Pappu L. N.; Phoenix, Leigh

    2007-01-01

    The NASA Engineering and Safety Center (NESC) has been conducting an independent technical assessment to address safety concerns related to the known stress rupture failure mode of filament wound pressure vessels in use on Shuttle and the International Space Station. The Shuttle's Kevlar-49 fiber overwrapped tanks are of particular concern due to their long usage and the poorly understood stress rupture process in Kevlar-49 filaments. Existing long term data show that the rupture process is a function of stress, temperature and time. However due to the presence of load sharing liners and the complex manufacturing procedures, the state of actual fiber stress in flight hardware and test articles is not clearly known. Indeed non-conservative life predictions have been made where stress rupture data and lifing procedures have ignored the contribution of the liner in favor of applied pressure as the controlling load parameter. With the aid of analytical and finite element results, this paper examines the fundamental mechanical response of composite overwrapped pressure vessels including the influence of elastic-plastic liners and degraded/creeping overwrap properties. Graphical methods are presented describing the non-linear relationship of applied pressure to Kevlar-49 fiber stress/strain during manufacturing, operations and burst loadings. These are applied to experimental measurements made on a variety of vessel systems to demonstrate the correct calibration of fiber stress as a function of pressure. Applying this analysis to the actual qualification burst data for Shuttle flight hardware revealed that the nominal fiber stress at burst was in some cases 23% lower than what had previously been used to predict stress rupture life. These results motivate a detailed discussion of the appropriate stress rupture lifing philosophy for COPVs including the correct transference of stress rupture life data between dissimilar vessels and test articles.

  9. Structural Health Monitoring of Composite Wound Pressure Vessels

    Science.gov (United States)

    Grant, Joseph; Kaul, Raj; Taylor, Scott; Jackson, Kurt; Myers, George; Sharma, A.

    2002-01-01

    The increasing use of advanced composite materials in the wide range of applications including Space Structures is a great impetus to the development of smart materials. Incorporating these FBG sensors for monitoring the integrity of structures during their life cycle will provide valuable information about viability of the usage of such material. The use of these sensors by surface bonding or embedding in this composite will measure internal strain and temperature, and hence the integrity of the assembled engineering structures. This paper focuses on such a structure, called a composite wound pressure vessel. This vessel was fabricated from the composite material: TRH50 (a Mitsubishi carbon fiber with a 710-ksi tensile strength and a 37 Msi modulus) impregnated with an epoxy resin from NEWPORT composites (WDE-3D-1). This epoxy resin in water dispersed system without any solvents and it cures in the 240-310 degrees F range. This is a toughened resin system specifically designed for pressure applications. These materials are a natural fit for fiber sensors since the polyimide outer buffer coating of fiber can be integrated into the polymer matrix of the composite material with negligible residual stress. The tank was wound with two helical patterns and 4 hoop wraps. The order of winding is: two hoops, two helical and two hoops. The wall thickness of the composite should be about 80 mil or less. The tank should burst near 3,000 psi or less. We can measure the actual wall thickness by ultrasonic or we can burst the tank and measure the pieces. Figure 1 shows a cylinder fabricated out of carbon-epoxy composite material. The strain in different directions is measured with a surface bonded fiber Bragg gratings and with embedded fiber Bragg gratings as the cylinder is pressurized to burst pressures. Figure 2 shows the strain as a function of pressure of carbon-epoxy cylinder as it is pressurized with water. Strain is measured in different directions by multiple gratings

  10. Design and Optimization of Filament Wound Composite Pressure Vessels

    NARCIS (Netherlands)

    Zu, L.

    2012-01-01

    One of the most important issues for the design of filament-wound pressure vessels reflects on the determination of the most efficient meridian profiles and related fiber architectures, leading to optimal structural performance. To better understand the design and optimization of filament-wound

  11. Finite element analysis of filament-wound composite pressure vessel under internal pressure

    Science.gov (United States)

    Sulaiman, S.; Borazjani, S.; Tang, S. H.

    2013-12-01

    In this study, finite element analysis (FEA) of composite overwrapped pressure vessel (COPV), using commercial software ABAQUS 6.12 was performed. The study deals with the simulation of aluminum pressure vessel overwrapping by Carbon/Epoxy fiber reinforced polymer (CFRP). Finite element method (FEM) was utilized to investigate the effects of winding angle on filament-wound pressure vessel. Burst pressure, maximum shell displacement and the optimum winding angle of the composite vessel under pure internal pressure were determined. The Laminae were oriented asymmetrically for [00,00]s, [150,-150]s, [300,-300]s, [450,-450]s, [550,-550]s, [600,-600]s, [750,-750]s, [900,-900]s orientations. An exact elastic solution along with the Tsai-Wu, Tsai-Hill and maximum stress failure criteria were employed for analyzing data. Investigations exposed that the optimum winding angle happens at 550 winding angle. Results were compared with the experimental ones and there was a good agreement between them.

  12. Online Monitoring of Composite Overwrapped Pressure Vessels (COPV)

    DEFF Research Database (Denmark)

    Pereira, Gilmar Ferreira; Figueiredo, Joana; Faria, Hugo

    2015-01-01

    -composite and composite-composite interfaces during their manufacturing processes. The idea is to allow the online strain monitoring during preliminary testing and service-life. The ability of these measuring systems to effectively assess the strain fields has been investigated. Simultaneously, a finite element analysis...... pressures are sought continuously, to get higher energy densities in such storage systems, and safety aspects become critical. Thus, reliable design and test procedures are required to reduce the risks of undesired and unpredicted failures. An in-service health monitoring system may contribute to a better...... product development, design and optimization, as well as to minimize the risks and improve the public acceptance. Within the scope of developing different COPV models for a wide range of operating pressures and applications, optical fiber Bragg grating (FBG) sensors were embedded in the liner...

  13. Vulnerability analysis of a pressurized aluminum composite vessel against hypervelocity impacts

    Directory of Open Access Journals (Sweden)

    Hereil Pierre-Louis

    2015-01-01

    Full Text Available Vulnerability of high pressure vessels subjected to high velocity impact of space debris is analyzed with the response of pressurized vessels to hypervelocity impact of aluminum sphere. Investigated tanks are CFRP (carbon fiber reinforced plastics overwrapped Al vessels. Explored internal pressure of nitrogen ranges from 1 bar to 300 bar and impact velocity are around 4400 m/s. Data obtained from Xrays radiographies and particle velocity measurements show the evolution of debris cloud and shock wave propagation in pressurized nitrogen. Observation of recovered vessels leads to the damage pattern and to its evolution as a function of the internal pressure. It is shown that the rupture mode is not a bursting mode but rather a catastrophic damage of the external carbon composite part of the vessel.

  14. Design of Semi-composite Pressure Vessel using Fuzzy and FEM

    Science.gov (United States)

    Sabour, Mohammad H.; Foghani, Mohammad F.

    2010-04-01

    The present study attempts to present a new method to design a semi-composite pressure vessel (known as hoop-wrapped composite cylinder) using fuzzy decision making and finite element method. A metal-composite vessel was designed based on ISO criteria and then the weight of the vessel was optimized for various fibers of carbon, glass and Kevlar in the cylindrical vessel. Failure criteria of von-Mises and Hoffman were respectively employed for the steel liner and the composite reinforcement to characterize the yielding/ buckling of the cylindrical pressure vessel. The fuzzy decision maker was used to estimate the thickness of the steel liner and the number of composite layers. The ratio of stresses on the composite fibers and the working pressure as well as the ratio of stresses on the composite fibers and the burst (failure) pressure were assessed. ANSYS nonlinear finite element solver was used to analyze the residual stress in the steel liner induced due to an auto-frettage process. Result of analysis verified that carbon fibers are the most suitable reinforcement to increase strength of cylinder while the weight stayed appreciably low.

  15. Development of Improved Composite Pressure Vessels for Hydrogen Storage

    Energy Technology Data Exchange (ETDEWEB)

    Newhouse, Norman L. [Hexagon Lincoln, Lincoln, NE (United States)

    2016-04-29

    Hexagon Lincoln started this DOE project as part of the Hydrogen Storage Engineering Center of Excellence (HSECoE) contract on 1 February 2009. The purpose of the HSECoE was the research and development of viable material based hydrogen storage systems for on-board vehicular applications to meet DOE performance and cost targets. A baseline design was established in Phase 1. Studies were then conducted to evaluate potential improvements, such as alternate fiber, resin, and boss materials. The most promising concepts were selected such that potential improvements, compared with the baseline Hexagon Lincoln tank, resulted in a projected weight reduction of 11 percent, volume increase of 4 percent, and cost reduction of 10 percent. The baseline design was updated in Phase 2 to reflect design improvements and changes in operating conditions specified by HSECoE Partners. Evaluation of potential improvements continued during Phase 2. Subscale prototype cylinders were designed and fabricated for HSECoE Partners’ use in demonstrating their components and systems. Risk mitigation studies were conducted in Phase 3 that focused on damage tolerance of the composite reinforcement. Updated subscale prototype cylinders were designed and manufactured to better address the HSECoE Partners’ requirements for system demonstration. Subscale Type 1, Type 3, and Type 4 tanks were designed, fabricated and tested. Laboratory tests were conducted to evaluate vacuum insulated systems for cooling the tanks during fill, and maintaining low temperatures during service. Full scale designs were prepared based on results from the studies of this program. The operating conditions that developed during the program addressed adsorbent systems operating at cold temperatures. A Type 4 tank would provide the lowest cost and lightest weight, particularly at higher pressures, as long as issues with liner compatibility and damage tolerance could be resolved. A Type 1 tank might be the choice if the

  16. Designing of a Fleet-Leader Program for Carbon Composite Overwrapped Pressure Vessels

    Science.gov (United States)

    Murthy, Pappu L.N.; Phoenix, S. Leigh

    2009-01-01

    Composite Overwrapped Pressure Vessels (COPVs) are often used for storing pressurant gases on board spacecraft when mass saving is a prime requirement. Substantial weight savings can be achieved compared to all metallic pressure vessels. For example, on the space shuttle, replacement of all metallic pressure vessels with Kevlar COPVs resulted in a weight savings of about 30 percent. Mass critical space applications such as the Ares and Orion vehicles are currently being planned to use as many COPVs as possible in place of all-metallic pressure vessels to minimize the overall mass of the vehicle. Due to the fact that overwraps are subjected to sustained loads during long periods of a mission, stress rupture failure is a major concern. It is, therefore, important to ascertain the reliability of these vessels by analysis, since it is practically impossible to show by experimental testing the reliability of flight quality vessels. Also, it is a common practice to set aside flight quality vessels as "fleet leaders" in a test program where these vessels are subjected to slightly accelerated operating conditions so that they lead the actual flight vessels both in time and load. The intention of fleet leaders is to provide advanced warning if there is a serious design flaw in the vessels so that a major disaster in the flight vessels can be averted with advance warning. On the other hand, the accelerating conditions must be not so severe as to be prone to false alarms. The primary focus of the present paper is to provide an analytical basis for designing a viable fleet leader program for carbon COPVs. The analysis is based on a stress rupture behavior model incorporating Weibull statistics and power-law sensitivity of life to fiber stress level.

  17. Development of a Numerical Model of Hypervelocity Impact into a Pressurized Composite Overwrapped Pressure Vessel

    Science.gov (United States)

    Garcia, M. A.; Davis, B. A.; Miller, J. E.

    2017-01-01

    As the outlook for space exploration becomes more ambitious and spacecraft travel deeper into space than ever before, it is increasingly important that propulsion systems perform reliably within the space environment. The increased reliability compels designers to increase design margin at the expense of system mass, which contrasts with the need to limit vehicle mass to maximize payload. Such are the factors that motivate the integration of high specific strength composite materials in the construction of pressure vessels commonly referred to as composite overwrapped pressure vessels (COPV). The COPV consists of a metallic liner for the inner shell of the COPV that is stiff, negates fluid permeation and serves as the anchor for composite laminates or filaments, but the liner itself cannot contain the stresses from the pressurant it contains. The compo-site-fiber reinforced polymer (CFRP) is wound around the liner using a combination of hoop (circumferential) and helical orientations. Careful consideration of wrap orientation allows the composite to evenly bear structural loading and creates the COPV's characteristic high strength to weight ratio. As the CFRP overwrap carries most of the stresses induced by pressurization, damage to the overwrap can affect mission duration, mission success and potentially cause loss-of-vehicle/loss-of-crew. For this reason, it is critical to establish a fundamental understanding of the mechanisms involved in the failure of a stressed composite such as that of the COPV. One of the greatest external threats to the integrity of a spacecraft's COPV is an impact from the meteoroid and orbital debris environments (MMOD). These impacts, even from submillimeter particles, generate extremely high stress states in the CFRP that can damage numerous fibers. As a result of this possibility, initial assumptions in survivability analysis for some human-rated NASA space-craft have assumed that any alteration of the vessel due to impact is

  18. Optimization of Composite Material System and Lay-up to Achieve Minimum Weight Pressure Vessel

    Science.gov (United States)

    Mian, Haris Hameed; Wang, Gang; Dar, Uzair Ahmed; Zhang, Weihong

    2013-10-01

    The use of composite pressure vessels particularly in the aerospace industry is escalating rapidly because of their superiority in directional strength and colossal weight advantage. The present work elucidates the procedure to optimize the lay-up for composite pressure vessel using finite element analysis and calculate the relative weight saving compared with the reference metallic pressure vessel. The determination of proper fiber orientation and laminate thickness is very important to decrease manufacturing difficulties and increase structural efficiency. In the present work different lay-up sequences for laminates including, cross-ply [ 0 m /90 n ] s , angle-ply [ ±θ] ns , [ 90/±θ] ns and [ 0/±θ] ns , are analyzed. The lay-up sequence, orientation and laminate thickness (number of layers) are optimized for three candidate composite materials S-glass/epoxy, Kevlar/epoxy and Carbon/epoxy. Finite element analysis of composite pressure vessel is performed by using commercial finite element code ANSYS and utilizing the capabilities of ANSYS Parametric Design Language and Design Optimization module to automate the process of optimization. For verification, a code is developed in MATLAB based on classical lamination theory; incorporating Tsai-Wu failure criterion for first-ply failure (FPF). The results of the MATLAB code shows its effectiveness in theoretical prediction of first-ply failure strengths of laminated composite pressure vessels and close agreement with the FEA results. The optimization results shows that for all the composite material systems considered, the angle-ply [ ±θ] ns is the optimum lay-up. For given fixed ply thickness the total thickness of laminate is obtained resulting in factor of safety slightly higher than two. Both Carbon/epoxy and Kevlar/Epoxy resulted in approximately same laminate thickness and considerable percentage of weight saving, but S-glass/epoxy resulted in weight increment.

  19. DEVELOPMENT OF ASME SECTION X CODE RULES FOR HIGH PRESSURE COMPOSITE HYDROGEN PRESSURE VESSELS WITH NON-LOAD SHARING LINERS

    Energy Technology Data Exchange (ETDEWEB)

    Rawls, G.; Newhouse, N.; Rana, M.; Shelley, B.; Gorman, M.

    2010-04-13

    The Boiler and Pressure Vessel Project Team on Hydrogen Tanks was formed in 2004 to develop Code rules to address the various needs that had been identified for the design and construction of up to 15000 psi hydrogen storage vessel. One of these needs was the development of Code rules for high pressure composite vessels with non-load sharing liners for stationary applications. In 2009, ASME approved new Appendix 8, for Section X Code which contains the rules for these vessels. These vessels are designated as Class III vessels with design pressure ranging from 20.7 MPa (3,000 ps)i to 103.4 MPa (15,000 psi) and maximum allowable outside liner diameter of 2.54 m (100 inches). The maximum design life of these vessels is limited to 20 years. Design, fabrication, and examination requirements have been specified, included Acoustic Emission testing at time of manufacture. The Code rules include the design qualification testing of prototype vessels. Qualification includes proof, expansion, burst, cyclic fatigue, creep, flaw, permeability, torque, penetration, and environmental testing.

  20. A Multiscale Modeling Approach to Analyze Filament-Wound Composite Pressure Vessels

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Ba Nghiep; Simmons, Kevin L.

    2013-07-22

    A multiscale modeling approach to analyze filament-wound composite pressure vessels is developed in this article. The approach, which extends the Nguyen et al. model [J. Comp. Mater. 43 (2009) 217] developed for discontinuous fiber composites to continuous fiber ones, spans three modeling scales. The microscale considers the unidirectional elastic fibers embedded in an elastic-plastic matrix obeying the Ramberg-Osgood relation and J2 deformation theory of plasticity. The mesoscale behavior representing the composite lamina is obtained through an incremental Mori-Tanaka type model and the Eshelby equivalent inclusion method [Proc. Roy. Soc. Lond. A241 (1957) 376]. The implementation of the micro-meso constitutive relations in the ABAQUS® finite element package (via user subroutines) allows the analysis of a filament-wound composite pressure vessel (macroscale) to be performed. Failure of the composite lamina is predicted by a criterion that accounts for the strengths of the fibers and of the matrix as well as of their interface. The developed approach is demonstrated in the analysis of a filament-wound pressure vessel to study the effect of the lamina thickness on the burst pressure. The predictions are favorably compared to the numerical and experimental results by Lifshitz and Dayan [Comp. Struct. 32 (1995) 313].

  1. Progressive Failure Analysis of Adhesive Joints of Filament-Wound Composite Pressure Vessel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Junhwan; Shin, Kwangbok [Hanbat National University, Daejeon (Korea, Republic of); Hwang, Taekyung [Agency for Defence Development, Daejeon (Korea, Republic of)

    2014-11-15

    This study performed the progressive failure analysis of adhesive joints of a composite pressure vessel with a separated dome by using a cohesive zone model. In order to determine the input parameters of a cohesive element for numerical analysis, the interlaminar fracture toughness values in modes I and II and in the mixed mode for the adhesive joints of the composite pressure vessel were obtained by a material test. All specimens were manufactured by the filament winding method. A mechanical test was performed on adhesively bonded double-lap joints to determine the shear strength of the adhesive joints and verify the reliability of the cohesive zone model for progressive failure analysis. The test results showed that the shear strength of the adhesive joints was 32MPa; the experiment and analysis results had an error of about 4.4%, indicating their relatively good agreement. The progressive failure analysis of a composite pressure vessel with an adhesively bonded dome performed using the cohesive zone model showed that only 5.8% of the total adhesive length was debonded and this debonded length did not affect the structural integrity of the vessel.

  2. Develop Critical Profilometers to Meet Current and Future Composite Overwrapped Pressure Vessel (COPV) Interior Inspection Needs

    Science.gov (United States)

    Saulsberry, Regor L.

    2010-01-01

    The objective of this project is to develop laser profilometer technology that can efficiently inspect and map the inside of composite pressure vessels for flaws such as liner buckling, pitting, or other surface imperfections. The project will also provide profilometers that can directly support inspections of flight vessels during development and qualification programs and subsequently be implemented into manufacturing inspections to screen out vessels with "out of family" liner defects. An example interior scan of a carbon overwrapped bottle is shown in comparison to an external view of the same bottle (Fig. 1). The internal scan is primarily of the cylindrical portion, but extends about 0.15 in. into the end cap area.

  3. Pressure vessel design manual

    CERN Document Server

    Moss, Dennis R

    2013-01-01

    Pressure vessels are closed containers designed to hold gases or liquids at a pressure substantially different from the ambient pressure. They have a variety of applications in industry, including in oil refineries, nuclear reactors, vehicle airbrake reservoirs, and more. The pressure differential with such vessels is dangerous, and due to the risk of accident and fatality around their use, the design, manufacture, operation and inspection of pressure vessels is regulated by engineering authorities and guided by legal codes and standards. Pressure Vessel Design Manual is a solutions-focused guide to the many problems and technical challenges involved in the design of pressure vessels to match stringent standards and codes. It brings together otherwise scattered information and explanations into one easy-to-use resource to minimize research and take readers from problem to solution in the most direct manner possible. * Covers almost all problems that a working pressure vessel designer can expect to face, with ...

  4. Evaluation of Carbon Composite Overwrap Pressure Vessels Fabricated Using Ionic Liquid Epoxies Project

    Science.gov (United States)

    Grugel, Richard

    2015-01-01

    The intent of the work proposed here is to ascertain the viability of ionic liquid (IL) epoxy based carbon fiber composites for use as storage tanks at cryogenic temperatures. This IL epoxy has been specifically developed to address composite cryogenic tank challenges associated with achieving NASA's in-space propulsion and exploration goals. Our initial work showed that an unadulterated ionic liquid (IL) carbon-fiber composite exhibited improved properties over an optimized commercial product at cryogenic temperatures. Subsequent investigative work has significantly improved the IL epoxy and our first carbon-fiber Composite Overwrap Pressure Vessel (COPV) was successfully fabricated. Here additional COPVs, using a further improved IL epoxy, will be fabricated and pressure tested at cryogenic temperatures with the results rigorously analyzed. Investigation of the IL composite for lower pressure liner-less cryogenic tank applications will also be initiated. It is expected that the current Technology Readiness Level (TRL) will be raised from about TRL 3 to TRL 5 where unambiguous predictions for subsequent development/testing can be made.

  5. Damage Control Plan for International Space Station Recharge Tank Assembly Composite Overwrapped Pressure Vessel

    Science.gov (United States)

    Cook, Anthony J.

    2011-01-01

    As NASA has retired the Space Shuttle Program, a new method of transporting compressed gaseous nitrogen and oxygen needed to be created for delivery of these crucial life support resources to the International Space Station (ISS). One of the methods selected by NASA includes the use of highly pressurized, unprotected Recharge Tank Assemblies (RTAs) utilizing Composite Overwrapped Pressure Vessels (COPVs). A COPV consists of a thin liner wrapped with a fiber composite and resin or epoxy. It is typically lighter weight than an all metal pressure vessel of similar volume and therefore provides a higher-efficiency means for gas storage. However COPVs are known to be susceptible to damage resulting from handling, tool drop impacts, or impacts from other objects. As a result, a comprehensive Damage Control Plan has been established to mitigate damage to the RTA COPV throughout its life cycle. The DCP is intended to evaluate and mitigate defined threats during manufacturing, shipping and handling, test, assembly level integration, shipment while pressurized, launch vehicle integration and mission operations by defining credible threats and methods for preventing potential damage while still maintaining the primary goal of resupplying ISS gas resources. A comprehensive threat assessment is performed to identify all threats posed to the COPV during the different phases of its lifecycle. The threat assessment is then used as the basis for creating a series of general inspection, surveillance and reporting requirements which apply across all phases of the COPV's life, targeted requirements only applicable to specific work phases and a series of training courses for both ground personnel and crew aboard the ISS. A particularly important area of emphasis deals with creating DCP requirements for a highly pressurized, large and unprotected RTA COPV for use during Inter Vehicular Activities (IVA) operations in the micro gravity environment while supplying pressurized gas to the

  6. Design prediction for long term stress rupture service of composite pressure vessels

    Science.gov (United States)

    Robinson, Ernest Y.

    1992-01-01

    Extensive stress rupture studies on glass composites and Kevlar composites were conducted by the Lawrence Radiation Laboratory beginning in the late 1960's and extending to about 8 years in some cases. Some of the data from these studies published over the years were incomplete or were tainted by spurious failures, such as grip slippage. Updated data sets were defined for both fiberglass and Kevlar composite stand test specimens. These updated data are analyzed in this report by a convenient form of the bivariate Weibull distribution, to establish a consistent set of design prediction charts that may be used as a conservative basis for predicting the stress rupture life of composite pressure vessels. The updated glass composite data exhibit an invariant Weibull modulus with lifetime. The data are analyzed in terms of homologous service load (referenced to the observed median strength). The equations relating life, homologous load, and probability are given, and corresponding design prediction charts are presented. A similar approach is taken for Kevlar composites, where the updated stand data do show a turndown tendency at long life accompanied by a corresponding change (increase) of the Weibull modulus. The turndown characteristic is not present in stress rupture test data of Kevlar pressure vessels. A modification of the stress rupture equations is presented to incorporate a latent, but limited, strength drop, and design prediction charts are presented that incorporate such behavior. The methods presented utilize Cartesian plots of the probability distributions (which are a more natural display for the design engineer), based on median normalized data that are independent of statistical parameters and are readily defined for any set of test data.

  7. Fibre composite pressure vessel with polymer liner. Tightness against hydrogen; Fiberforstaerket trykbeholder med polymerliner - Taethed over for brint

    Energy Technology Data Exchange (ETDEWEB)

    Lystrup, Aage

    2005-10-01

    Pressure vessels are used as hydrogen storage on-board the car in a Danish hydrogen car project. To save energy the pressure vessels should have low weight, and carbon fibre composite pressure vessels were used. To ensure complete tightness against hydrogen, the vessels have an internal liner of aluminium. For structural reason the liner is relatively thick and the liner constitutes half of the weight of the complete pressure vessel. Further weight reduction can be obtained if the metal liner is replaced by a polymer liner, but this also means that the vessel no longer will be 100 % tight, as hydrogen will diffuse through the polymer liner. The diffusion of hydrogen can be reduced if the polymer liner is coated with a thin metal layer. Small 0.4-litre fibre composite pressure vessels with polymer liner and metal coated polymer liner were manufactured and the hydrogen tightness of the vessels were determined by measuring the weight loss during a period of 6 years of vessels pressurised by hydrogen to 10 MPa, equivalent to a hydrogen content of about 3.3 g. The loss of hydrogen during the first 3 years from vessels with pure polymer liner occurred linearly with an average loss of 0.055 g per month, or about 1.8 % per month. The loss of hydrogen from the vessels with metal coated liner occurred almost linear in the whole 6-years period. The average loss was 0.028 g per month for a vessel with a liner coated with a layer of a combination of Cu and Ag by vacuum deposition. The average loss was 0.017 g per month for a vessel with a liner coated with a plasma sprayed layer of Cu. This means that the metal coated liners are 2-3 times tighter than the pure polymer liner. The relative loss of hydrogen would be less for a larger pressure vessel with a larger ratio between volume and surface area. As an example, the relative loss for the 9-litre pressure vessel used in the Danish hydrogen car project would be 3.3 times less than the relative loss for the small 0.4 litre vessel

  8. PRESSURE-RESISTANT VESSEL

    NARCIS (Netherlands)

    Beukers, A.; De Jong, T.

    1997-01-01

    Abstract of WO 9717570 (A1) The invention is directed to a wheel-shaped pressure-resistant vessel for gaseous, liquid or liquefied material having a substantially rigid shape, said vessel comprising a substantially continuous shell of a fiber-reinforced resin having a central opening, an inner

  9. A Theoretical Investigation of Composite Overwrapped Pressure Vessel (COPV) Mechanics Applied to NASA Full Scale Tests

    Science.gov (United States)

    Thesken, John C.; Murthy, Pappu L. N.; Phoenix, S. L.; Greene, N.; Palko, Joseph L.; Eldridge, Jeffrey; Sutter, James; Saulsberry, R.; Beeson, H.

    2009-01-01

    A theoretical investigation of the factors controlling the stress rupture life of the National Aeronautics and Space Administration's (NASA) composite overwrapped pressure vessels (COPVs) continues. Kevlar (DuPont) fiber overwrapped tanks are of particular concern due to their long usage and the poorly understood stress rupture process in Kevlar filaments. Existing long term data show that the rupture process is a function of stress, temperature and time. However due to the presence of a load sharing liner, the manufacturing induced residual stresses and the complex mechanical response, the state of actual fiber stress in flight hardware and test articles is not clearly known. This paper is a companion to a previously reported experimental investigation and develops a theoretical framework necessary to design full-scale pathfinder experiments and accurately interpret the experimentally observed deformation and failure mechanisms leading up to static burst in COPVs. The fundamental mechanical response of COPVs is described using linear elasticity and thin shell theory and discussed in comparison to existing experimental observations. These comparisons reveal discrepancies between physical data and the current analytical results and suggest that the vessel s residual stress state and the spatial stress distribution as a function of pressure may be completely different from predictions based upon existing linear elastic analyses. The 3D elasticity of transversely isotropic spherical shells demonstrates that an overly compliant transverse stiffness relative to membrane stiffness can account for some of this by shifting a thin shell problem well into the realm of thick shell response. The use of calibration procedures are demonstrated as calibrated thin shell model results and finite element results are shown to be in good agreement with the experimental results. The successes reported here have lead to continuing work with full scale testing of larger NASA COPV

  10. Variabilities detected by acoustic emission from filament-wound Aramid fiber/epoxy composite pressure vessels

    Science.gov (United States)

    Hamstad, M. A.

    1978-01-01

    Two hundred and fifty Aramid fiber/epoxy pressure vessels were filament-wound over spherical aluminum mandrels under controlled conditions typical for advanced filament-winding. A random set of 30 vessels was proof-tested to 74% of the expected burst pressure; acoustic emission data were obtained during the proof test. A specially designed fixture was used to permit in situ calibration of the acoustic emission system for each vessel by the fracture of a 4-mm length of pencil lead (0.3 mm in diameter) which was in contact with the vessel. Acoustic emission signatures obtained during testing showed larger than expected variabilities in the mechanical damage done during the proof tests. To date, identification of the cause of these variabilities has not been determined.

  11. The Cyogenic Evaluation of Irradiated Composite Materials for Use in Composite Pressure Vessels Project

    Data.gov (United States)

    National Aeronautics and Space Administration — HyPerComp Engineering, Inc. (HEI) proposes to continue the characterization of the cryogenic evaluation of irradiated composite materials for use in composite...

  12. GOLD PRESSURE VESSEL SEAL

    Science.gov (United States)

    Smith, A.E.

    1963-11-26

    An improved seal between the piston and die member of a piston-cylinder type pressure vessel is presented. A layer of gold, of sufficient thickness to provide an interference fit between the piston and die member, is plated on the contacting surface of at least one of the members. (AEC)

  13. Pressurized Vessel Slurry Pumping

    Energy Technology Data Exchange (ETDEWEB)

    Pound, C.R.

    2001-09-17

    This report summarizes testing of an alternate ''pressurized vessel slurry pumping'' apparatus. The principle is similar to rural domestic water systems and ''acid eggs'' used in chemical laboratories in that material is extruded by displacement with compressed air.

  14. An Integrated Acousto/Ultrasonic Structural Health Monitoring System for Composite Pressure Vessels.

    Science.gov (United States)

    Bulletti, Andrea; Giannelli, Pietro; Calzolai, Marco; Capineri, Lorenzo

    2016-06-01

    This paper describes the implementation of a structural health monitoring (SHM) method for mechanical components and structures in composite materials with a focus on carbon-fiber-overwrapped pressure vessels (COPVs) used in the aerospace industry. Two flex arrays of polyvinylidene fluoride (PVDF) interdigital transducers have been designed, realized, and mounted on the COPV to generate guided Lamb waves (mode A0) for damage assessment. We developed a custom electronic instrument capable of performing two functions using the same transducers: passive-mode detection of impacts and active-mode damage assessment using Lamb waves. The impact detection is based on an accurate evaluation of the time of arrival and was successfully tested with low-velocity impacts (7 and 30 J). Damage detection and progression is based on the calculation of a damage index matrix which compares a set of signals acquired from the transducers with a baseline. This paper also investigates the advantage of tuning the active-mode frequency to obtain the maximum transducer response in the presence of structural variations of the specimen, and therefore, the highest sensitivity to damage.

  15. Nondestructive Methods and Special Test Instrumentation Supporting NASA Composite Overwrapped Pressure Vessel Assessments

    Science.gov (United States)

    Saulsberry, Regor; Greene, Nathanael; Cameron, Ken; Madaras, Eric; Grimes-Ledesma, Lorie; Thesken, John; Phoenix, Leigh; Murthy, Pappu; Revilock, Duane

    2007-01-01

    Many aging composite overwrapped pressure vessels (COPVs), being used by the National Aeronautics and Space Administration (NASA) are currently under evaluation to better quantify their reliability and clarify their likelihood of failure due to stress rupture and age-dependent issues. As a result, some test and analysis programs have been successfully accomplished and other related programs are still in progress at the NASA Johnson Space Center (JSC) White Sands Test Facility (WSTF) and other NASA centers, with assistance from the commercial sector. To support this effort, a group of Nondestructive Evaluation (NDE) experts was assembled to provide NDE competence for pretest evaluation of test articles and for application of NDE technology to real-time testing. Techniques were required to provide assurance that the test article had adequate structural integrity and manufacturing consistency to be considered acceptable for testing and these techniques were successfully applied. Destructive testing is also being accomplished to better understand the physical and chemical property changes associated with progression toward "stress rupture" (SR) failure, and it is being associated with NDE response, so it can potentially be used to help with life prediction. Destructive work also includes the evaluation of residual stresses during dissection of the overwrap, laboratory evaluation of specimens extracted from the overwrap to evaluate physical property changes, and quantitative microscopy to inform the theoretical micromechanics.

  16. A Comparison of Various Stress Rupture Life Models for Orbiter Composite Pressure Vessels and Confidence Intervals

    Science.gov (United States)

    Grimes-Ledesma, Lorie; Murthy, Pappu L. N.; Phoenix, S. Leigh; Glaser, Ronald

    2007-01-01

    In conjunction with a recent NASA Engineering and Safety Center (NESC) investigation of flight worthiness of Kevlar Overwrapped Composite Pressure Vessels (COPVs) on board the Orbiter, two stress rupture life prediction models were proposed independently by Phoenix and by Glaser. In this paper, the use of these models to determine the system reliability of 24 COPVs currently in service on board the Orbiter is discussed. The models are briefly described, compared to each other, and model parameters and parameter uncertainties are also reviewed to understand confidence in reliability estimation as well as the sensitivities of these parameters in influencing overall predicted reliability levels. Differences and similarities in the various models will be compared via stress rupture reliability curves (stress ratio vs. lifetime plots). Also outlined will be the differences in the underlying model premises, and predictive outcomes. Sources of error and sensitivities in the models will be examined and discussed based on sensitivity analysis and confidence interval determination. Confidence interval results and their implications will be discussed for the models by Phoenix and Glaser.

  17. The cryogenic bonding evaluation at the metallic-composite interface of a composite overwrapped pressure vessel with additional impact investigation

    Science.gov (United States)

    Clark, Eric A.

    A bonding evaluation that investigated the cryogenic tensile strength of several different adhesives/resins was performed. The test materials consisted of 606 aluminum test pieces adhered to a wet-wound graphite laminate in order to simulate the bond created at the liner-composite interface of an aluminum-lined composite overwrapped pressure vessel. It was found that for cryogenic applications, a flexible, low modulus resin system must be used. Additionally, the samples prepared with a thin layer of cured resin -- or prebond -- performed significantly better than those without. It was found that it is critical that the prebond surface must have sufficient surface roughness prior to the bonding application. Also, the aluminum test pieces that were prepared using a surface etchant slightly outperformed those that were prepared with a grit blast surface finish and performed significantly better than those that had been scored using sand paper to achieve the desired surface finish. An additional impact investigation studied the post impact tensile strength of composite rings in a cryogenic environment. The composite rings were filament wound with several combinations of graphite and aramid fibers and were prepared with different resin systems. The rings were subjected to varying levels of Charpy impact damage and then pulled to failure in tension. It was found that the addition of elastic aramid fibers with the carbon fibers mitigates the overall impact damage and drastically improves the post-impact strength of the structure in a cryogenic environment.

  18. The Cyogenic Evaluation of Irradiated Composite Materials for Use in Composite Pressure Vessels Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The intent of this proposal is to develop key building block technology for lightweight composite structures suitable for cryogenic fuel depot storage as well as...

  19. Standard practice for examination of Gas-Filled filament-wound composite pressure vessels using acoustic emission

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This practice provides guidelines for acoustic emission (AE) examination of filament-wound composite pressure vessels, for example, the type used for fuel tanks in vehicles which use natural gas fuel. 1.2 This practice requires pressurization to a level equal to or greater than what is encountered in normal use. The tanks' pressurization history must be known in order to use this practice. Pressurization medium may be gas or liquid. 1.3 This practice is limited to vessels designed for less than 690 bar [10,000 psi] maximum allowable working pressure and water volume less than 1 m3 or 1000 L [35.4 ft3]. 1.4 AE measurements are used to detect emission sources. Other nondestructive examination (NDE) methods may be used to gain additional insight into the emission source. Procedures for other NDE methods are beyond the scope of this practice. 1.5 This practice applies to examination of new and in-service filament-wound composite pressure vessels. 1.6 This practice applies to examinations conducted at amb...

  20. Manufacturing Cost Analysis of Novel Steel/Concrete Composite Vessel for Stationary Storage of High-Pressure Hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Zhili [ORNL; Zhang, Wei [ORNL; Wang, Jy-An John [ORNL; Ren, Fei [ORNL

    2012-09-01

    A novel, low-cost, high-pressure, steel/concrete composite vessel (SCCV) technology for stationary storage of compressed gaseous hydrogen (CGH2) is currently under development at Oak Ridge National Laboratory (ORNL) sponsored by DOE s Fuel Cell Technologies (FCT) Program. The SCCV technology uses commodity materials including structural steels and concretes for achieving cost, durability and safety requirements. In particular, the hydrogen embrittlement of high-strength low-alloy steels, a major safety and durability issue for current industry-standard pressure vessel technology, is mitigated through the use of a unique layered steel shell structure. This report presents the cost analysis results of the novel SCCV technology. A high-fidelity cost analysis tool is developed, based on a detailed, bottom-up approach which takes into account the material and labor costs involved in each of the vessel manufacturing steps. A thorough cost study is performed to understand the SCCV cost as a function of the key vessel design parameters, including hydrogen pressure, vessel dimensions, and load-carrying ratio. The major conclusions include: The SCCV technology can meet the technical/cost targets set forth by DOE s FCT Program for FY2015 and FY2020 for all three pressure levels (i.e., 160, 430 and 860 bar) relevant to the hydrogen production and delivery infrastructure. Further vessel cost reduction can benefit from the development of advanced vessel fabrication technologies such as the highly automated friction stir welding (FSW). The ORNL-patented multi-layer, multi-pass FSW can not only reduce the amount of labor needed for assembling and welding the layered steel vessel, but also make it possible to use even higher strength steels for further cost reductions and improvement of vessel structural integrity. It is noted the cost analysis results demonstrate the significant cost advantage attainable by the SCCV technology for different pressure levels when compared to the

  1. Strain measurement during stress rupture of composite over-wrapped pressure vessel with fiber Bragg gratings sensors

    Science.gov (United States)

    Banks, Curtis E.; Grant, Joseph; Russell, Sam; Arnett, Shawn

    2008-03-01

    Fiber optic Bragg gratings were used to measure strain fields during Stress Rupture (SSM) test of Kevlar Composite Over-Wrapped Pressure Vessels (COPVs). The sensors were embedded under the over-wrapped attached to the liner released from the Kevlar and attached to the Kevlar released from the liner. Additional sensors (foil gages and fiber bragg gratings) were surface mounted on the COPV liner.

  2. Pressure vessel design manual

    Energy Technology Data Exchange (ETDEWEB)

    Moss, D.R.

    1987-01-01

    The first section of the book covers types of loadings, failures, and stress theories, and how they apply to pressure vessels. The book delineates the procedures for designing typical components as well as those for designing large openings in cylindrical shells, ring girders, davits, platforms, bins and elevated tanks. The techniques for designing conical transitions, cone-cylinder intersections, intermediate heads, flat heads, and spherically dished covers are also described. The book covers the design of vessel supports subject to wind and seismic loads and one section is devoted to the five major ways of analyzing loads on shells and heads. Each procedure is detailed enough to size all welds, bolts, and plate thicknesses and to determine actual stresses.

  3. Damage evaluation and analysis of composite pressure vessels using fiber Bragg gratings to determine structural health

    Science.gov (United States)

    Ortyl, Nicholas E.

    2005-11-01

    . Multiaxis fiber optic sensors are able to measure pressure, temperature, axial and transverse strain, chemical properties, corrosion, as well as transverse strain gradients. This technology is easily embedded in between the various layers of the composite structure, during manufacture, without compromising the structural integrity, in order to verify manufacturing parameters during the cure cycle and well as monitor the on-going condition of the composite structure throughout its life time. This paper reviews some of the technical work that has been accomplished during the past two years; specifically the embedding of fiber optic sensors into various composite structures in order to be able to conduct in situ non-destructive evaluation of the curing process and the service life of the component. The fiber optic technology has been developed to the point that it is at a TRL of 6.

  4. The Cryogenic Impact Resistant Evaluation of Filament Wound Materials for Use in Composite Pressure Vessels Project

    Data.gov (United States)

    National Aeronautics and Space Administration — HyPerComp Engineering Inc. (HEI) and Utah State University (USU) propose to develop technology for lightweight composite materials for use in composite structures...

  5. Sialyte(TM)-Based Composite Pressure Vessels for Extreme Environments Project

    Data.gov (United States)

    National Aeronautics and Space Administration — While traveling to Venus, electronics and instruments go through enormous pressure, temperature, and atmospheric environment changes. In the past, this has caused...

  6. In-Situ Nondestructive Evaluation of Kevlar(Registered Trademark)and Carbon Fiber Reinforced Composite Micromechanics for Improved Composite Overwrapped Pressure Vessel Health Monitoring

    Science.gov (United States)

    Waller, Jess; Saulsberry, Regor

    2012-01-01

    NASA has been faced with recertification and life extension issues for epoxy-impregnated Kevlar 49 (K/Ep) and carbon (C/Ep) composite overwrapped pressure vessels (COPVs) used in various systems on the Space Shuttle and International Space Station, respectively. Each COPV has varying criticality, damage and repair histories, time at pressure, and pressure cycles. COPVs are of particular concern due to the insidious and catastrophic burst-before-leak failure mode caused by stress rupture (SR) of the composite overwrap. SR life has been defined [1] as the minimum time during which the composite maintains structural integrity considering the combined effects of stress level(s), time at stress level(s), and associated environment. SR has none of the features of predictability associated with metal pressure vessels, such as crack geometry, growth rate and size, or other features that lend themselves to nondestructive evaluation (NDE). In essence, the variability or surprise factor associated with SR cannot be eliminated. C/Ep COPVs are also susceptible to impact damage that can lead to reduced burst pressure even when the amount of damage to the COPV is below the visual detection threshold [2], thus necessitating implementation of a mechanical damage control plan [1]. Last, COPVs can also fail prematurely due to material or design noncompliance. In each case (SR, impact or noncompliance), out-of-family behavior is expected leading to a higher probability of failure at a given stress, hence, greater uncertainty in performance. For these reasons, NASA has been actively engaged in research to develop NDE methods that can be used during post-manufacture qualification, in-service inspection, and in-situ structural health monitoring. Acoustic emission (AE) is one of the more promising NDE techniques for detecting and monitoring, in real-time, the strain energy release and corresponding stress-wave propagation produced by actively growing flaws and defects in composite

  7. Pressure vessel and method therefor

    Energy Technology Data Exchange (ETDEWEB)

    Saunders, Timothy

    2017-09-05

    A pressure vessel includes a pump having a passage that extends between an inlet and an outlet. A duct at the pump outlet includes at least one dimension that is adjustable to facilitate forming a dynamic seal that limits backflow of gas through the passage.

  8. Hydrogen storage in insulated pressure vessels

    Energy Technology Data Exchange (ETDEWEB)

    Aceves, S.M.; Garcia-Villazana, O. [Lawrence Livermore National Lab., CA (United States)

    1998-08-01

    Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen (LH{sub 2}) or ambient-temperature compressed hydrogen (CH{sub 2}). Insulated pressure vessels offer the advantages of liquid hydrogen tanks (low weight and volume), with reduced disadvantages (lower energy requirement for hydrogen liquefaction and reduced evaporative losses). This paper shows an evaluation of the applicability of the insulated pressure vessels for light-duty vehicles. The paper shows an evaluation of evaporative losses and insulation requirements and a description of the current analysis and experimental plans for testing insulated pressure vessels. The results show significant advantages to the use of insulated pressure vessels for light-duty vehicles.

  9. Reactor pressure vessel. Status report

    Energy Technology Data Exchange (ETDEWEB)

    Elliot, B.J.; Hackett, E.M.; Lee, A.D. [and others

    1996-10-01

    This report describes the issues raised as a result of the staffs review of Generic Letter (GL) 92-01, Revision 1, responses and plant-specific reactor pressure vessel (RPV) assessments and the actions taken or work in progress to address these issues. In addition, the report describes actions taken by the staff and the nuclear industry to develop a thermal annealing process for use at U.S. commercial nuclear power plants. This process is intended to be used as a means of mitigating the effects of neutron radiation on the fracture toughness of RPV materials. The Nuclear Regulatory Commission (NRC) issued GL 92-01, Revision 1, Supplement 1, to obtain information needed to assess compliance with regulatory requirements and licensee commitments regarding RPV integrity. GL 92-01, Revision 1, Supplement 1, was issued as a result of generic issues that were raised in the NRC staff`s reviews of licensee responses to GL 92-01, Revision 1, and plant-specific RPV evaluations. In particular, an integrated review of all data submitted in response to GL 92-01, Revision 1, indicated that licensees may not have considered all relevant data in their RPV assessments. This report is representative of submittals to and evaluations by the staff as of September 30, 1996. An update of this report will be issued at a later date.

  10. Smart Composite Overwrapped Pressure Vessel - Integrated Structural Health Monitoring System to Meet Space Exploration and International Space Station Mission Assurance Needs

    Science.gov (United States)

    Saulsberry, Regor; Nichols, Charles; Waller, Jess

    2012-01-01

    Currently there are no integrated NDE methods for baselining and monitoring defect levels in fleet for Composite Overwrapped Pressure Vessels (COPVs) or related fracture critical composites, or for performing life-cycle maintenance inspections either in a traditional remove-and-inspect mode or in a more modern in situ inspection structural health monitoring (SHM) mode. Implicit in SHM and autonomous inspection is the existence of quantitative accept-reject criteria. To be effective, these criteria must correlate with levels of damage known to cause composite failure. Furthermore, implicit in SHM is the existence of effective remote sensing hardware and automated techniques and algorithms for interpretation of SHM data. SHM of facture critical composite structures, especially high pressure COPVs, is critical to the success of nearly every future NASA space exploration program as well as life extension of the International Space Station. It has been clearly stated that future NASA missions may not be successful without SHM [1]. Otherwise, crews will be busy addressing subsystem health issues and not focusing on the real NASA mission

  11. High Toughness Light Weight Pressure Vessel Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Proposed is a pressure vessel with 25% better Fracture Strength over equal strength designed Fiberglass to help reduce 10 to 25% weight for aerospace use. Phase I is...

  12. Liquid Nitrogen Subcooler Pressure Vessel Engineering Note

    Energy Technology Data Exchange (ETDEWEB)

    Rucinski, R.; /Fermilab

    1997-04-24

    The normal operating pressure of this dewar is expected to be less than 15 psig. This vessel is open to atmospheric pressure thru a non-isolatable vent line. The backpressure in the vent line was calculated to be less than 1.5 psig at maximum anticipated flow rates.

  13. Continued Development of Meandering Winding Magnetometer (MWM (Register Trademark)) Eddy Current Sensors for the Health Monitoring, Modeling and Damage Detection of Composite Overwrapped Pressure Vessels

    Science.gov (United States)

    Russell, Richard; Wincheski, Russell; Jablonski, David; Washabaugh, Andy; Sheiretov, Yanko; Martin, Christopher; Goldfine, Neil

    2011-01-01

    Composite Overwrapped Pressure Vessels (COPVs) are used in essentially all NASA spacecraft, launch. vehicles and payloads to contain high-pressure fluids for propulsion, life support systems and science experiments. Failure of any COPV either in flight or during ground processing would result in catastrophic damage to the spacecraft or payload, and could lead to loss of life. Therefore, NASA continues to investigate new methods to non-destructively inspect (NDE) COPVs for structural anomalies and to provide a means for in-situ structural health monitoring (SHM) during operational service. Partnering with JENTEK Sensors, engineers at NASA, Kennedy Space Center have successfully conducted a proof-of-concept study to develop Meandering Winding Magnetometer (MWM) eddy current sensors designed to make direct measurements of the stresses of the internal layers of a carbon fiber composite wrapped COPV. During this study three different MWM sensors were tested at three orientations to demonstrate the ability of the technology to measure stresses at various fiber orientations and depths. These results showed good correlation with actual surface strain gage measurements. MWM-Array technology for scanning COPVs can reliably be used to image and detect mechanical damage. To validate this conclusion, several COPVs were scanned to obtain a baseline, and then each COPV was impacted at varying energy levels and then rescanned. The baseline subtracted images were used to demonstrate damage detection. These scans were performed with two different MWM-Arrays. with different geometries for near-surface and deeper penetration imaging at multiple frequencies and in multiple orientations of the linear MWM drive. This presentation will include a review of micromechanical models that relate measured sensor responses to composite material constituent properties, validated by the proof of concept study, as the basis for SHM and NDE data analysis as well as potential improvements including

  14. Health Monitoring of Composite Overwrapped Pressure Vessels (COPVs) Using Meandering Winding Magnetometer ((MWM(Registered Trademark)) Eddy Current Sensors

    Science.gov (United States)

    Russell, Rick; Grundy, David; Jablonski, David; Martin, Christopher; Washabaugh, Andrew; Goldfine, Neil

    2011-01-01

    There are 3 mechanisms that affect the life of a COPV are: a) The age life of the overwrap; b) Cyclic fatigue of the metallic liner; c) Stress Rupture life. The first two mechanisms are understood through test and analysis. A COPV Stress Rupture is a sudden and catastrophic failure of the overwrap while holding at a stress level below the ultimate strength for an extended time. Currently there is no simple, deterministic method of determining the stress rupture life of a COPV, nor a screening technique to determine if a particular COPV is close to the time of a stress rupture failure. Conclusions: Demonstrated a correlation between MWM response and pressure or strain. Demonstrated the ability to monitor stress in COPV at different orientations and depths. FA41 provides best correlation with bottle pressure or stress.

  15. Compressibility measurements of gases using externally heated pressure vessels.

    Science.gov (United States)

    Presnall, D. C.

    1971-01-01

    Most of the data collected under conditions of high temperature and pressure have been determined using a thick-walled bomb of carefully measured and fixed volume which is externally heated by an electric furnace or a thermostatically controlled bath. There are numerous variations on the basic method depending on the pressure-temperature range of interest, and the particular gas or gas mixture being studied. The construction and calibration of the apparatus is discussed, giving attention to the pressure vessel, the volume of the bomb, the measurement of pressure, the control and measurement of temperature, and the measurement of the amount and composition of gas in the bomb.

  16. Providing Pressurized Gasses to the International Space Station (ISS): Developing a Composite Overwrapped Pressure Vessel (COPV) for the Safe Transport of Oxygen and Nitrogen

    Science.gov (United States)

    Kezirian, Michael; Cook, Anthony; Dick, Brandon; Phoenix, S. Leigh

    2012-01-01

    To supply oxygen and nitrogen to the International Space Station, a COPV tank is being developed to meet requirements beyond that which have been flown. In order to "Ship Full' and support compatibility with a range of launch site operations, the vessel was designed for certification to International Standards (ISO) that have a different approach than current NASA certification approaches. These requirements were in addition to existing NASA certification standards had to be met. Initial risk-reduction development tests have been successful. Qualification is in progress.

  17. Conformable pressure vessel for high pressure gas storage

    Energy Technology Data Exchange (ETDEWEB)

    Simmons, Kevin L.; Johnson, Kenneth I.; Lavender, Curt A.; Newhouse, Norman L.; Yeggy, Brian C.

    2016-01-12

    A non-cylindrical pressure vessel storage tank is disclosed. The storage tank includes an internal structure. The internal structure is coupled to at least one wall of the storage tank. The internal structure shapes and internally supports the storage tank. The pressure vessel storage tank has a conformability of about 0.8 to about 1.0. The internal structure can be, but is not limited to, a Schwarz-P structure, an egg-crate shaped structure, or carbon fiber ligament structure.

  18. Kendall Analysis of Cannon Pressure Vessels

    Science.gov (United States)

    2012-04-11

    Comparisons”, Journal of Pressure Vessel Technology, Vol. 123, 271-281. [5] Underwood, J.H., deSwardt, R.R., Venter, A.M., Troiano , E., Hyland...Pressure and Fatigue Life,” ASME PVP Conference, San Antonio, TX, July 22-26, 2007. [6] J.H. Underwood, A.P. Parker, E. Troiano , 2006, “Effect of...Paris and G..R. Irwin, 1985, The Stress Analysis of Cracks Handbook, Paris Productions Inc., St. Louis, MO. [8] E. Troiano , A.P. Parker and J.H

  19. Could Nano-Structured Materials Enable the Improved Pressure Vessels for Deep Atmospheric Probes?

    Science.gov (United States)

    Srivastava, D.; Fuentes, A.; Bienstock, B.; Arnold, J. O.

    2005-01-01

    A viewgraph presentation on the use of Nano-Structured Materials to enable pressure vessel structures for deep atmospheric probes is shown. The topics include: 1) High Temperature/Pressure in Key X-Environments; 2) The Case for Use of Nano-Structured Materials Pressure Vessel Design; 3) Carbon based Nanomaterials; 4) Nanotube production & purification; 5) Nanomechanics of Carbon Nanotubes; 6) CNT-composites: Example (Polymer); 7) Effect of Loading sequence on Composite with 8% by volume; 8) Models for Particulate Reinforced Composites; 9) Fullerene/Ti Composite for High Strength-Insulating Layer; 10) Fullerene/Epoxy Composite for High Strength-Insulating Layer; 11) Models for Continuous Fiber Reinforced Composites; 12) Tensile Strength for Discontinuous Fiber Composite; 13) Ti + SWNT Composites: Thermal/Mechanical; 14) Ti + SWNT Composites: Tensile Strength; and 15) Nano-structured Shell for Pressure Vessels.

  20. Nuclear reactor pressure vessel support system

    Science.gov (United States)

    Sepelak, George R.

    1978-01-01

    A support system for nuclear reactor pressure vessels which can withstand all possible combinations of stresses caused by a postulated core disrupting accident during reactor operation. The nuclear reactor pressure vessel is provided with a flange around the upper periphery thereof, and the flange includes an annular vertical extension formed integral therewith. A support ring is positioned atop of the support ledge and the flange vertical extension, and is bolted to both members. The plug riser is secured to the flange vertical extension and to the top of a radially outwardly extension of the rotatable plug. This system eliminates one joint through which fluids contained in the vessel could escape by making the fluid flow path through the joint between the flange and the support ring follow the same path through which fluid could escape through the plug risers. In this manner, the sealing means to prohibit the escape of contained fluids through the plug risers can also prohibit the escape of contained fluid through the securing joint.

  1. The Cryogenic Impact Resistant Evaluation of Composite Materials for Use in Composite Pressure Vessels with an Additional Cryogenic Bonding Scope Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The intent of the proposed effort is to investigate the detailed composite material performance characteristics after being subjected to cryogenic temperatures and...

  2. Structural integrity of nuclear reactor pressure vessels

    Science.gov (United States)

    Knott, John F.

    2013-09-01

    The paper starts from concerns expressed by Sir Alan Cottrell, in the early 1970s, related to the safety of the pressurized water reactor (PWR) proposed at that time for the next phase of electrical power generation. It proceeds to describe the design and operation of nuclear generation plant and gives details of the manufacture of PWR reactor pressure vessels (RPVs). Attention is paid to stress-relief cracking and under-clad cracking, experienced with early RPVs, explaining the mechanisms for these forms of cracking and the means taken to avoid them. Particular note is made of the contribution of non-destructive inspection to structural integrity. Factors affecting brittle fracture in RPV steels are described: in particular, effects of neutron irradiation. The use of fracture mechanics to assess defect tolerance is explained, together with the failure assessment diagram embodied in the R6 procedure. There is discussion of the Master Curve and how it incorporates effects of irradiation on fracture toughness. Dangers associated with extrapolation of data to low probabilities are illustrated. The treatment of fatigue-crack growth is described, in the context of transients that may be experienced in the operation of PWR plant. Detailed attention is paid to the thermal shock associated with a large loss-of-coolant accident. The final section reviews the arguments advanced to justify 'Incredibility of Failure' and how these are incorporated in assessments of the integrity of existing plant and proposed 'new build' PWR pressure vessels.

  3. Reactor Pressure Vessel (RPV) Acquisition Strategy

    Energy Technology Data Exchange (ETDEWEB)

    Mizia, Ronald Eugene [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2008-04-01

    The Department of Energy has selected the High Temperature Gas-cooled Reactor design for the Next Generation Nuclear Plant (NGNP) Project. The NGNP will demonstrate the use of nuclear power for electricity and hydrogen production. It will have an outlet gas temperature in the range of 900°C and a plant design service life of 60 years. The reactor design will be a graphite moderated, helium-cooled, prismatic or pebble-bed reactor and use low-enriched uranium, TRISO-coated fuel. The plant size, reactor thermal power, and core configuration will ensure passive decay heat removal without fuel damage or radioactive material releases during accidents. The NGNP Materials Research and Development (R&D) Program is responsible for performing R&D on likely NGNP materials in support of the NGNP design, licensing, and construction activities. Selection of the technology and design configuration for the NGNP must consider both the cost and risk profiles to ensure that the demonstration plant establishes a sound foundation for future commercial deployments. The NGNP challenge is to achieve a significant advancement in nuclear technology while at the same time setting the stage for an economically viable deployment of the new technology in the commercial sector soon after 2020. The purpose of this report is to address the acquisition strategy for the NGNP Reactor Pressure Vessel (RPV). This component will be larger than any nuclear reactor pressure vessel presently in service in the United States. The RPV will be taller, larger in diameter, thicker walled, heavier and most likely fabricated at the Idaho National Laboratory (INL) site of multiple subcomponent pieces. The pressure vessel steel can either be a conventional materials already used in the nuclear industry such as listed within ASME A508/A533 specifications or it will be fabricated from newer pressure vessel materials never before used for a nuclear reactor in the US. Each of these characteristics will present a

  4. Radiation effects on reactor pressure vessel supports

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, R.E. [Nuclear Regulatory Commission, Washington, DC (United States). Div. of Engineering Technology; Lipinski, R.E. [Idaho National Engineering Lab., Rockville, MD (United States)

    1996-05-01

    The purpose of this report is to present the findings from the work done in accordance with the Task Action Plan developed to resolve the Nuclear Regulatory Commission (NRC) Generic Safety Issue No. 15, (GSI-15). GSI-15 was established to evaluate the potential for low-temperature, low-flux-level neutron irradiation to embrittle reactor pressure vessel (RPV) supports to the point of compromising plant safety. An evaluation of surveillance samples from the High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory (ORNL) had suggested that some materials used for RPV supports in pressurized-water reactors could exhibit higher than expected embrittlement rates. However, further tests designed to evaluate the applicability of the HFIR data to reactor RPV supports under operating conditions led to the conclusion that RPV supports could be evaluated using traditional method. It was found that the unique HFIR radiation environment allowed the gamma radiation to contribute significantly to the embrittlement. The shielding provided by the thick steel RPV shell ensures that degradation of RPV supports from gamma irradiation is improbable or minimal. The findings reported herein were used, in part, as the basis for technical resolution of the issue.

  5. Composite Vessels for Containment of Extreme Blast Loadings

    Energy Technology Data Exchange (ETDEWEB)

    Pastrnak, J; Henning, C; Grundler, W; Switzer, V; Hollaway, R; Morrison, J; Hagler, L; Kokko, E; Deteresa, S; Hathcoat, B; Dalder, E

    2004-07-15

    A worldwide trend for explosives testing has been to replace open-air detonations with containment vessels, especially when any hazardous materials are involved. As part of the National Nuclear Security Administration's (NNSA) effort to ensure the safety and reliability of the nation's nuclear stockpile, researchers at Lawrence Livermore National Laboratory have been developing a high performance filament wound composite firing vessel that is nearly radiographically transparent. It was intended to contain a limited number of detonations of metal cased explosive assemblies in radiographic facilities such as the Advanced Hydrodynamic Facility (AHF) being studied by Los Alamos National Laboratory. A 2-meter diameter pressure vessel was designed to contain up to 35 kg (80 lb) of TNT equivalent explosive without leakage. Over the past 5 years a total of three half-scale (1 meter diameter) vessels have been constructed, and two of them were tested to 150% load with 8.2 kg (18-pound) spheres of C4 explosive. The low density and high specific strength advantages used in this composite vessel design may have other additional applications such as transporting sensitive explosives that could otherwise be moved only in very small quantities. Also, it could be used for highly portable, explosive containment systems for law enforcement.

  6. Transient evolution of inter vessel gap pressure due to relative thermal expansion between two vessels

    Science.gov (United States)

    Natesan, K.; Selvaraj, P.; Chellapandi, P.; Chetal, S. C.

    2002-08-01

    In a typical liquid metal cooled fast breeder reactor (LMFBR), a cylindrical sodium filled main vessel, which carries the internals such as reactor core, pumps, intermediate heat exchangers etc. is surrounded by another vessel called safety vessel. The inter vessel gap is filled with nitrogen. During a thermal transient in the pool sodium, because of the relative delay involved in the thermal diffusion between MV and SV, they are subjected to relative thermal expansion or contraction between them. This in turn results in pressurisation and depressurisation of inter vessel gap nitrogen respectively. In order to obtain the external pressurization for the buckling design of MV, transient thermal models for obtaining the evolutions of MV, SV and inter gap nitrogen temperatures and hence their relative thermal expansion and inter vessel gap pressure have been developed. This paper gives the details of the mathematical model, assumptions made in the calculation and the results of the analysis.

  7. Firefighter's compressed air breathing system pressure vessel development program

    Science.gov (United States)

    Beck, E. J.

    1974-01-01

    The research to design, fabricate, test, and deliver a pressure vessel for the main component in an improved high-performance firefighter's breathing system is reported. The principal physical and performance characteristics of the vessel which were required are: (1) maximum weight of 9.0 lb; (2) maximum operating pressure of 4500 psig (charge pressure of 4000 psig); (3) minimum contained volume of 280 in. 3; (4) proof pressure of 6750 psig; (5) minimum burst pressure of 9000 psig following operational and service life; and (6) a minimum service life of 15 years. The vessel developed to fulfill the requirements described was completely sucessful, i.e., every category of performence was satisfied. The average weight of the vessel was found to be about 8.3 lb, well below the 9.0 lb specification requirement.

  8. Expert system for determining welding condition for a pressure vessel

    National Research Council Canada - National Science Library

    Fukuda, Shuichi; Morita, Hideki; Yamauchi, Yoshihisa; Nagasawa, Isao; Tsuji, Shuichi

    1990-01-01

    This paper describes the outline of the expert system for producing a Welding Procedure Specification for a pressure vessel which was developed with the grant from the Ministry of International Trade...

  9. Low-Cost, Lightweight Pressure Vessel Proof Test

    Science.gov (United States)

    Chanez, Eric

    This experiment seeks to determine the burst strength of the low-cost, lightweight pressure vessel fabricated by the Suborbital Center of Excellence (SCE). Moreover, the test explores the effects of relatively large gage pressures on material strain for ‘pumpkin-shaped' pressure vessels. The SCE team used pressure transducers and analog gauges to measure the gage pressure while a video camera assembly recorded several gores in the shell for strain analysis. The team loaded the vessel in small intervals of pressure until the structure failed. Upon test completion, the pressure readings and video recordings were analyzed to determine the burst strength and material strain in the shell. The analysis yielded a burst pressure of 13.5 psi while the strain analysis reported in the shell. While the results of this proof test are encouraging, the structure's factor of safety must be increased for actual balloon flights. Furthermore, the pressure vessel prototype must be subjected to reliability tests to show the design can sustain gage pressures for the length of a balloon flight.

  10. Analysis and Design of Cryogenic Pressure Vessels for Automotive Hydrogen Storage

    Science.gov (United States)

    Espinosa-Loza, Francisco Javier

    Cryogenic pressure vessels maximize hydrogen storage density by combining the high pressure (350-700 bar) typical of today's composite pressure vessels with the cryogenic temperature (as low as 25 K) typical of low pressure liquid hydrogen vessels. Cryogenic pressure vessels comprise a high-pressure inner vessel made of carbon fiber-coated metal (similar to those used for storage of compressed gas), a vacuum space filled with numerous sheets of highly reflective metalized plastic (for high performance thermal insulation), and a metallic outer jacket. High density of hydrogen storage is key to practical hydrogen-fueled transportation by enabling (1) long-range (500+ km) transportation with high capacity vessels that fit within available spaces in the vehicle, and (2) reduced cost per kilogram of hydrogen stored through reduced need for expensive structural material (carbon fiber composite) necessary to make the vessel. Low temperature of storage also leads to reduced expansion energy (by an order of magnitude or more vs. ambient temperature compressed gas storage), potentially providing important safety advantages. All this is accomplished while simultaneously avoiding fuel venting typical of cryogenic vessels for all practical use scenarios. This dissertation describes the work necessary for developing and demonstrating successive generations of cryogenic pressure vessels demonstrated at Lawrence Livermore National Laboratory. The work included (1) conceptual design, (2) detailed system design (3) structural analysis of cryogenic pressure vessels, (4) thermal analysis of heat transfer through cryogenic supports and vacuum multilayer insulation, and (5) experimental demonstration. Aside from succeeding in demonstrating a hydrogen storage approach that has established all the world records for hydrogen storage on vehicles (longest driving range, maximum hydrogen storage density, and maximum containment of cryogenic hydrogen without venting), the work also

  11. Investigation of impulsively loaded pressure vessels

    Energy Technology Data Exchange (ETDEWEB)

    Brown, N.; Cornwell, R.; Hanner, D.; Leichter, H.; Mohr, P.

    1963-10-15

    Explosion containment vessels for containing from 2,000 to 3,000 five ton nuclear explosions are considered. Analysis methods appear adequate and lowest weights using the most advanced materials available in the next five years are projected.None of these materials can be fabricated today and all require extensive development. Present material technology limits the choice of materials and defines the weight. The addition of safety factors and fixtures (nozzles, etc.) will add to this weight considerably, and may well radically alter the vessel response. Improvements in the strength weight ratios of metals and glasses over those considered in this report do not appear reasonable at this time. Winding schemes to utilize the high strength of steel wires and somehow maintain a reasonable thickness appear to offer the most promise. A `ductile` beryllium would of course offer vast improvement, but no indications that this is being developed have appeared and all presently known beryllium is much too brittle.

  12. Interpretation of Strain Measurements on Nuclear Pressure Vessels

    DEFF Research Database (Denmark)

    Andersen, Svend Ib Smidt; Engbæk, Preben

    1980-01-01

    Selected results from strain measurements on four nuclear pressure vessels are presented and discussed. The measurements were made in several different regions of the vessels: transition zones in vessel heads, flanges and bottom parts, nozzles, internal vessel structure and flange bolts. The resu......Selected results from strain measurements on four nuclear pressure vessels are presented and discussed. The measurements were made in several different regions of the vessels: transition zones in vessel heads, flanges and bottom parts, nozzles, internal vessel structure and flange bolts....... The results presented are based on data obtained by approximately 700 strain-gauges, and a comprehensive knowledge of the quality obtained by such measurements is established. It is shown that a thorough control procedure before and after the test as well as a detailed knowledge of the behaviour of the signal...... from the individual gauges during the test is necessary. If this is omitted, it can be extremely difficult to distinguish between the real structural behaviour and a malfunctioning of a specific gauge installation. In general, most of the measuring results exhibit a very linear behaviour...

  13. Technical Appendix to Cryogenic Pressure Vessels

    Energy Technology Data Exchange (ETDEWEB)

    Mulholland, G.T.; Rucinski, R.A; /Fermilab

    1990-02-22

    The 20,000 gls. Liquid Argon dewar stores up to 15,000 gls. of high purity (<1.0 ppm O{sub 2}, 0.999995) LAr for use in the Liquid Argon calorimeters of E740, the D0 collider detector, at elevation 707-feet. The dewar provides for the total detector volume of 11,000 gls and a 4,000 gls. storage inventory. The large gas volume ({ge}5,000 gls.) serves operational needs and guards against overfill concerns. The LAr dewar functions in two modes: (1) low pressure (16 psi relief) storage, and liquid and gas transfer operations to and from the low pressure (13 psi relief) detector cryostats, and (2) high pressure (65 psi relief) liquid transfer operations to and from a delivery trailer at elevation 743-feet. The storage function is intended to be long term and nonventing. The dewar is equipped with a 40 kW LN{sub 2} condenser that operates to maintain the pressure constant in the storage mode. This service exactly parallels the NeH{sub 2} and D{sub 2} storage dewar services provided at the 15-feet bubble chamber for its operation.

  14. 46 CFR 54.01-10 - Steam-generating pressure vessels (modifies U-1(g)).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Steam-generating pressure vessels (modifies U-1(g)). 54... ENGINEERING PRESSURE VESSELS General Requirements § 54.01-10 Steam-generating pressure vessels (modifies U-1(g)). (a) Pressure vessels in which steam is generated are classed as “Unfired Steam Boilers” except as...

  15. Heritability of retinal vessel diameters and blood pressure

    DEFF Research Database (Denmark)

    Taarnhøj, Nina C B B; Larsen, Michael; Sander, Birgit

    2006-01-01

    for CRVE, and 0.67 +/- 0.05 microm for AVR. No significant influence on artery or vein diameters was found for gender, smoking, body mass index (BMI), total cholesterol, fasting blood glucose, or 2-hour oral glucose tolerance test values. CONCLUSIONS: In healthy young adults with normal blood pressure...... and blood glucose, variations in retinal blood vessel diameters and blood pressure were predominantly attributable to genetic effects. A genetic influence may have a role in individual susceptibility to hypertension and other vascular diseases. The results suggest that retinal vessel diameters...

  16. Industrial safety of pressure vessels - structural integrity point of view

    Directory of Open Access Journals (Sweden)

    Sedmak Aleksandar

    2016-01-01

    Full Text Available This paper presents different aspects of pressure vessel safety in the scope of industrial safety, focused to the chemical industry. Quality assurance, including application of PED97/23 has been analysed first, followed shortly by the risk assessment and in details by the structural integrity approach, which has been illustrated with three case studies. One important conclusion, following such an approach, is that so-called water proof testing can actually jeopardize integrity of a pressure vessel instead of proving it. [Projekat Ministarstva nauke Republike Srbije, br. TR 174004 i br. TR 33044

  17. Low Temperature and High Pressure Evaluation of Insulated Pressure Vessels for Cryogenic Hydrogen Storage

    Energy Technology Data Exchange (ETDEWEB)

    Aceves, S.; Martinez-Frias, J.; Garcia-Villazana, O.

    2000-06-25

    Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen (LH{sub 2}) or ambient-temperature compressed hydrogen (CH{sub 2}). Insulated pressure vessels offer the advantages of liquid hydrogen tanks (low weight and volume), with reduced disadvantages (fuel flexibility, lower energy requirement for hydrogen liquefaction and reduced evaporative losses). The work described here is directed at verifying that commercially available pressure vessels can be safely used to store liquid hydrogen. The use of commercially available pressure vessels significantly reduces the cost and complexity of the insulated pressure vessel development effort. This paper describes a series of tests that have been done with aluminum-lined, fiber-wrapped vessels to evaluate the damage caused by low temperature operation. All analysis and experiments to date indicate that no significant damage has resulted. Required future tests are described that will prove that no technical barriers exist to the safe use of aluminum-fiber vessels at cryogenic temperatures.

  18. USER SPECIFICATIONS FOR PRESSURE VESSELS AND TECHNICAL INTEGRITY

    Directory of Open Access Journals (Sweden)

    K.S. Johnston

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: Specifications translated from user requirements are prescribed in an attempt to capture and incorporate best practices with regards to the design, fabrication, testing, and operation of pressure vessels. The question as to whether these requirements affect the technical integrity of pressure vessels is often a subjective matter. This paper examines typical user requirement specifications against technical integrity of pressure vessels.
    The paper draws on a survey of a convenience sample of practising engineers in a diversified petrochemical company. When compared with failures on selected pressure vessels recorded by Phillips and Warwick, the respondent feedback confirms the user specifications that have the highest impact on technical integrity.

    AFRIKAANSE OPSOMMING: Gebruikersbehoeftes word saamgevat in spesifikasies wat lei tot goeie praktyk vir ontwerp, vervaarding, toetsing en bedryf van drukvate. Subjektiwiteit van die gebruikersbehoeftes mag soms die tegniese integriteit van ‘n drukvat beinvloed.
    Die navorsing maak by wyse van monsterneming gebruik van die kennis van ingenieurs wat werk in ‘n gediversifiseerde petrochemiese bedryf. Die terugvoering bevestig dat bogenoemde spesifikasies inderdaad die grootste invloed het op tegniese integriteit.

  19. Residual Stress Estimation and Fatigue Life Prediction of an Autofrettaged Pressure Vessel

    Energy Technology Data Exchange (ETDEWEB)

    Song, Kyung Jin; Kim, Eun Kyum; Koh, Seung Kee [Kunsan Nat’l Univ., Kunsan (Korea, Republic of)

    2017-09-15

    Fatigue failure of an autofrettaged pressure vessel with a groove at the outside surface occurs owing to the fatigue crack initiation and propagation at the groove root. In order to predict the fatigue life of the autofrettaged pressure vessel, residual stresses in the autofrettaged pressure vessel were evaluated using the finite element method, and the fatigue properties of the pressure vessel steel were obtained from the fatigue tests. Fatigue life of a pressure vessel obtained through summation of the crack initiation and propagation lives was calculated to be 2,598 cycles for an 80% autofrettaged pressure vessel subjected to a pulsating internal pressure of 424 MPa.

  20. Optimal design of high pressure hydrogen storage vessel using an adaptive genetic algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ping [Institute of Applied Mechanics, Zhejiang University, Hangzhou 310027 (China); Zheng, Jinyang; Chen, Honggang; Liu, Pengfei [Institute of Chemical Machinery and Process Equipment, Zhejiang University, Hangzhou 310027 (China)

    2010-04-15

    The weight minimum optimization of composite hydrogen storage vessel under the burst pressure constraint is considered. An adaptive genetic algorithm is proposed to perform the optimal design of composite vessels. The proposed optimization algorithm considers the adaptive probabilities of crossover and mutation which change with the fitness values of individuals and proposes a penalty function to deal with the burst pressure constraint. The winding thickness and angles of composite layers are chosen as the design variables. Effects of the population size and the number of generations on the optimal results are explored. The results using the adaptive genetic algorithm are also compared with those using the simple genetic algorithm and the Monte Carlo optimization method. (author)

  1. Circular cylinders and pressure vessels stress analysis and design

    CERN Document Server

    Vullo, Vincenzo

    2014-01-01

    This book provides comprehensive coverage of stress and strain analysis of circular cylinders and pressure vessels, one of the classic topics of machine design theory and methodology. Whereas other books offer only a partial treatment of the subject and frequently consider stress analysis solely in the elastic field, Circular Cylinders and Pressure Vessels broadens the design horizons, analyzing theoretically what happens at pressures that stress the material beyond its yield point and at thermal loads that give rise to creep. The consideration of both traditional and advanced topics ensures that the book will be of value for a broad spectrum of readers, including students in postgraduate, and doctoral programs and established researchers and design engineers. The relations provided will serve as a sound basis for the design of products that are safe, technologically sophisticated, and compliant with standards and codes and for the development of innovative applications.

  2. Lessons Learned From Developing Reactor Pressure Vessel Steel Embrittlement Database

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jy-An John [ORNL

    2010-08-01

    Materials behaviors caused by neutron irradiation under fission and/or fusion environments can be little understood without practical examination. Easily accessible material information system with large material database using effective computers is necessary for design of nuclear materials and analyses or simulations of the phenomena. The developed Embrittlement Data Base (EDB) at ORNL is this comprehensive collection of data. EDB database contains power reactor pressure vessel surveillance data, the material test reactor data, foreign reactor data (through bilateral agreements authorized by NRC), and the fracture toughness data. The lessons learned from building EDB program and the associated database management activity regarding Material Database Design Methodology, Architecture and the Embedded QA Protocol are described in this report. The development of IAEA International Database on Reactor Pressure Vessel Materials (IDRPVM) and the comparison of EDB database and IAEA IDRPVM database are provided in the report. The recommended database QA protocol and database infrastructure are also stated in the report.

  3. Some Observations on Damage Tolerance Analyses in Pressure Vessels

    Science.gov (United States)

    Raju, Ivatury S.; Dawicke, David S.; Hampton, Roy W.

    2017-01-01

    AIAA standards S080 and S081 are applicable for certification of metallic pressure vessels (PV) and composite overwrap pressure vessels (COPV), respectively. These standards require damage tolerance analyses with a minimum reliable detectible flaw/crack and demonstration of safe life four times the service life with these cracks at the worst-case location in the PVs and oriented perpendicular to the maximum principal tensile stress. The standards require consideration of semi-elliptical surface cracks in the range of aspect ratios (crack depth a to half of the surface length c, i.e., (a/c) of 0.2 to 1). NASA-STD-5009 provides the minimum reliably detectible standard crack sizes (90/95 probability of detection (POD) for several non-destructive evaluation (NDE) methods (eddy current (ET), penetrant (PT), radiography (RT) and ultrasonic (UT)) for the two limits of the aspect ratio range required by the AIAA standards. This paper tries to answer the questions: can the safe life analysis consider only the life for the crack sizes at the two required limits, or endpoints, of the (a/c) range for the NDE method used or does the analysis need to consider values within that range? What would be an appropriate method to interpolate 90/95 POD crack sizes at intermediate (a/c) values? Several procedures to develop combinations of a and c within the specified range are explored. A simple linear relationship between a and c is chosen to compare the effects of seven different approaches to determine combinations of aj and cj that are between the (a/c) endpoints. Two of the seven are selected for evaluation: Approach I, the simple linear relationship, and a more conservative option, Approach III. For each of these two Approaches, the lives are computed for initial semi-elliptic crack configurations in a plate subjected to remote tensile fatigue loading with an R-ratio of 0.1, for an assumed material evaluated using NASGRO (registered 4) version 8.1. These calculations demonstrate

  4. 46 CFR 154.650 - Cargo tank and process pressure vessel welding.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo tank and process pressure vessel welding. 154.650... Equipment Construction § 154.650 Cargo tank and process pressure vessel welding. (a) Cargo tank and process pressure vessel welding must meet Subpart 54.05 and Part 57 of this chapter. (b) Welding consumables used...

  5. 46 CFR 78.33-1 - Repairs of boiler and pressure vessels.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Repairs of boiler and pressure vessels. 78.33-1 Section... OPERATIONS Reports of Accidents, Repairs, and Unsafe Equipment § 78.33-1 Repairs of boiler and pressure vessels. (a) Before making any repairs to boilers or unfired pressure vessels, the chief engineer shall...

  6. Treating asphericity in fuel particle pressure vessel modeling

    Science.gov (United States)

    Miller, Gregory K.; Wadsworth, Derek C.

    1994-07-01

    The prototypical nuclear fuel of the New Production Modular High Temperature Gas-Cooled Reactor (NP-MHTGR) consists of spherical TRISO-coated particles suspended in graphite cylinders. The coating layers surrounding the fuel kernels in these particles consist of pyrolytic carbon layers and a silicon carbide layer. These coating layers act as a pressure vessel which retains fission product gases. In the operating conditions of the NP-MHTGR, a small percentage of these particles (pressure vessels) are expected to fail due to the pressure loading. The fuel particles of the NP-MHTGR deviate to some degree from a true spherical shape, which may have some effect on the failure percentages. A method is presented that treats the asphericity of the particles in predicting failure probabilities for particle samples. It utilizes a combination of finite element analysis and Monte Carlo sampling and is based on the Weibull statistical theory. The method is used here to assess the effects of asphericity in particles of two common geometric shapes, i.e. faceted particles and ellipsoidal particles. The method presented could be used to treat particle anomalies other than asphericity.

  7. Evaluation of Data-Logging Transducer to Passively Collect Pressure Vessel p/T History

    Science.gov (United States)

    Wnuk, Stephen P.; Le, Son; Loew, Raymond A.

    2013-01-01

    Pressure vessels owned and operated by NASA are required to be regularly certified per agency policy. Certification requires an assessment of damage mechanisms and an estimation of vessel remaining life. Since detail service histories are not typically available for most pressure vessels, a conservative estimate of vessel pressure/temperature excursions is typically used in assessing fatigue life. This paper details trial use of a data-logging transducer to passively obtain actual pressure and temperature service histories of pressure vessels. The approach was found to have some potential for cost savings and other benefits in certain cases.

  8. Fatigue crack propagation in steels for reactor pressure vessels

    Energy Technology Data Exchange (ETDEWEB)

    Klesnil, M.; Lukas, P.; Kunz, L. (Ceskoslovenska Akademie Ved, Brno. Ustav Fyzikalni Metalurgie); Troshchenko, V.T.; Pokrovskij, V.V.; Yasnij, P.V.; Skorenko, Y.S. (AN Ukrainskoj SSR, Kiev. Inst. Problem Prochnosti)

    1983-01-01

    Fatigue crack propagation data were measured on 15Kh2NMFA steel of Czechoslovak and Soviet makes. The results obtained by two laboratories were compared with other available data regarding materials for pressure vessels of nuclear power plants. Crack propagation curves were measured at temperatures -60, 20 and 350 degC and the corresponding parameters of crack growth equation were found. Threshold values of stress intensity factor amplitude, Ksub(apz), and the influence of stress ratio R in the range of small crack rates were determined experimentally. Fractography revealed either transgranular or mixed transgranular and interaranular fracture modes depending on stress intensity amplitude Ksub(a) and the environment.

  9. Optimization of reactor pressure vessel internals segmentation in Korea

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Byung-Sik [Dankook Univ., Chungnam (Korea, Republic of). Dept. of Nuclear Engineering

    2017-11-15

    One of the most challenging tasks during plant decommissioning is the removal of highly radioactive internal components from the reactor pressure vessel (RPV). For RPV internals dismantling, it is essential that all activities are thoroughly planned and discussed in the early stage of the decommissioning project. One of the key activities in the detailed planning is to prepare the segmentation and packaging plan that describes the sequential steps required to segment, separate, and package each individual component of RPV, based on an activation analysis and component characterization study.

  10. FLUOLE-2: An Experiment for PWR Pressure Vessel Surveillance

    Directory of Open Access Journals (Sweden)

    Thiollay Nicolas

    2016-01-01

    Full Text Available FLUOLE-2 is a benchmark-type experiment dedicated to 900 and 1450 MWe PWR vessels surveillance dosimetry. This two-year program started in 2014 and will end in 2015. It will provide precise experimental data for the validation of the neutron spectrum propagation calculation from core to vessel. It is composed of a square core surrounded by a stainless steel baffe and internals: PWR barrel is simulated by steel structures leading to different steel-water slides; two steel components stand for a surveillance capsule holder and for a part of the pressure vessel. Measurement locations are available on the whole experimental structure. The experimental knowledge of core sources will be obtained by integral gamma scanning measurements directly on fuel pins. Reaction rates measured by calibrated fission chambers and a large set of dosimeters will give information on the neutron energy and spatial distributions. Due to the low level neutron flux of EOLE ZPR a special, high efficiency, calibrated gamma spectrometry device will be used for some dosimeters, allowing to measure an activity as low as 7. 10−2 Bq per sample. 103mRh activities will be measured on an absolute calibrated X spectrometry device. FLUOLE-2 experiment goal is to usefully complete the current experimental benchmarks database used for the validation of neutron calculation codes. This two-year program completes the initial FLUOLE program held in 2006–2007 in a geometry representative of 1300 MWe PWR.

  11. Test of 6-in. -thick pressure vessels. Series 3: intermediate test vessel V-7. [PWR and BWR

    Energy Technology Data Exchange (ETDEWEB)

    Merkle, J.G.; Robinson, G.C.; Holz, P.P.; Smith, J.E.; Bryan, R.H.

    1976-08-01

    The test of intermediate test vessel V-7 was a crack-initiation fracture test of a 152-mm-thick (6-in.), 990-mm-OD (39-in.) vessel of ASTM A533, grade B, class 1 steel plate with a sharp outside surface flaw 457 mm (18 in.) long and about 135 mm (5.3 in.) deep. The vessel was heated to 91/sup 0/C (196/sup 0/F) and pressurized hydraulically until leakage through the flaw terminated the test at a peak pressure of 147 MPa (21,350 psi). Fracture toughness data obtained by testing precracked Charpy-V and compact-tension specimens machined from a prolongation of the cylindrical test shell were used in pretest analyses of the flawed vessel. The vessel, as expected, did not burst. Upon depressurization, the ruptured ligament closed so as to maintain static pressure without leakage at about 129 MPa (18,700 psi).

  12. Optical Measurement Technology for Calibratiing Inner Defects of Pressure Vessel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Do; Chang, Seog Weon; Jhang, Kyung Young [Hanyang University, Seoul (Korea, Republic of)

    2005-04-15

    The pressure vessel may have crucial defects in its inner surfaces, which can be more dangerous than those in outer surfaces because the inner defects can hardly be measured or calibrated. Conventional methods for detecting or measuring the inner defects of pressure vessel have been utilizing ultrasonic, X-ray or eddy current. But the conventional NDE(Non-Destructive-Evaluation) methods are applied to limited area or environment because the prove or film must be located close to the objects although the methods are NDE tools. Recently, optical measurement technologies for detecting the inner defects such as cracks, flaws or corrosions are utilized very much. The optical measurement technologies are known as much useful as to have the capabilities of short working time, non-contact and full-field measurement. Among them, shearography is considered to be one of the most available tools, because of its feature of not requiring strict environmental stability, which is essential to other optical tools. In this study, the availability of the optical measurement technology using shearography for detecting and calibrating the inner defects is verified.

  13. Carbon fiber composites for cryogenic filament-wound vessels

    Science.gov (United States)

    Larsen, J. V.; Simon, R. A.

    1972-01-01

    Advanced unidirectional and bidirectional carbon fiber/epoxy resin composites were evaluated for physical and mechanical properties over a cryogenic to room temperature range for potential application to cryogenic vessels. The results showed that Courtaulds HTS carbon fiber was the superior fiber in terms of cryogenic strength properties in epoxy composites. Of the resin systems tested in ring composites, CTBN/ERLB 4617 exhibited the highest composite strengths at cryogenic temperatures, but very low interlaminar shear strengths at room temperature. Tests of unidirectional and bidirectional composite bars showed that the Epon 828/Empol 1040 resin was better at all test temperatures. Neither fatigue cycling nor thermal shock had a significant effect on composite strengths or moduli. Thermal expansion measurements gave negative values in the fiber direction and positive values in the transverse direction of the composites.

  14. NASA Requirements for Ground-Based Pressure Vessels and Pressurized Systems (PVS). Revision C

    Science.gov (United States)

    Greulich, Owen Rudolf

    2017-01-01

    The purpose of this document is to ensure the structural integrity of PVS through implementation of a minimum set of requirements for ground-based PVS in accordance with this document, NASA Policy Directive (NPD) 8710.5, NASA Safety Policy for Pressure Vessels and Pressurized Systems, NASA Procedural Requirements (NPR) 8715.3, NASA General Safety Program Requirements, applicable Federal Regulations, and national consensus codes and standards (NCS).

  15. Blood pressure, vessel caliber, and retinal thickness in diabetes.

    Science.gov (United States)

    Harrison, Wendy W; Chang, Ann; Cardenas, Maria G; Bearse, Marcus A; Schneck, Marilyn E; Barez, Shirin; Adams, Anthony J

    2012-12-01

    In this study, we examine the association of blood pressure (BP), retinal thickness (RT), and vessel caliber in patients with type 2 diabetes and high HbA1c (elevated long-term blood glucose) with or without mild or moderate nonproliferative diabetic retinopathy (NPDR). Forty-three patients with type 2 diabetes and high HbA1c measures (23 without NPDR and 20 with mild to moderate NPDR) and 22 age-matched nondiabetic controls participated. The BP, RT (Stratus OCT3), fundus photography, and HbA1c were measured. Correlations between BP, HbA1c, vessel caliber, and RT were evaluated. Diastolic BP (DBP) is positively and significantly associated with RT in patients with NPDR (p < 0.02). Blood pressure was not associated with RT in patients without NPDR (p = 0.83). There is an association between higher HbA1c and higher DBP within the NPDR group (p < 0.02). Furthermore, HbA1c modifies the slope of the relationship between DBP and RT in NPDR patients. Greater venule diameters and loss of the correlation between decreased arteriole size and increased systolic blood pressure, seen in controls, were observed in patients with and without NPDR. The results of this study show that HbA1c and BP together have an impact on RT measures of patients with DR. These measures should be considered when evaluating RT in patients with DR both clinically and in future optical coherence tomography studies on this population.

  16. Low Temperature Irradiation Embrittlement of Reactor Pressure Vessel Steels

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jy-An John [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-08-01

    The embrittlement trend curve development project for HFIR reactor pressure vessel (RPV) steels was carried out with three major tasks. Which are (1) data collection to match that used in HFIR steel embrittlement trend published in 1994 Journal Nuclear Material by Remec et. al, (2) new embrittlement data of A212B steel that are not included in earlier HFIR RPV trend curve, and (3) the adjustment of nil-ductility-transition temperature (NDTT) shift data with the consideration of the irradiation temperature effect. An updated HFIR RPV steel embrittlement trend curve was developed, as described below. NDTT( C) = 23.85 log(x) + 203.3 log (x) + 434.7, with 2- uncertainty of 34.6 C, where parameter x is referred to total dpa. The developed update HFIR RPV embrittlement trend curve has higher embrittlement rate compared to that of the trend curve developed in 1994.

  17. Crystal Plasticity Model of Reactor Pressure Vessel Embrittlement in GRIZZLY

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Pritam [Idaho National Laboratory (INL), Idaho Falls, ID (United States); Biner, Suleyman Bulent [Idaho National Laboratory (INL), Idaho Falls, ID (United States); Zhang, Yongfeng [Idaho National Laboratory (INL), Idaho Falls, ID (United States); Spencer, Benjamin Whiting [Idaho National Laboratory (INL), Idaho Falls, ID (United States)

    2015-07-01

    The integrity of reactor pressure vessels (RPVs) is of utmost importance to ensure safe operation of nuclear reactors under extended lifetime. Microstructure-scale models at various length and time scales, coupled concurrently or through homogenization methods, can play a crucial role in understanding and quantifying irradiation-induced defect production, growth and their influence on mechanical behavior of RPV steels. A multi-scale approach, involving atomistic, meso- and engineering-scale models, is currently being pursued within the GRIZZLY project to understand and quantify irradiation-induced embrittlement of RPV steels. Within this framework, a dislocation-density based crystal plasticity model has been developed in GRIZZLY that captures the effect of irradiation-induced defects on the flow stress behavior and is presented in this report. The present formulation accounts for the interaction between self-interstitial loops and matrix dislocations. The model predictions have been validated with experiments and dislocation dynamics simulation.

  18. Macrosegregation and Microstructural Evolution in a Pressure-Vessel Steel

    Science.gov (United States)

    Pickering, E. J.; Bhadeshia, H. K. D. H.

    2014-06-01

    This work assesses the consequences of macrosegregation on microstructural evolution during solid-state transformations in a continuously cooled pressure-vessel steel (SA508 Grade 3). Stark spatial variations in microstructure are observed following a simulated quench from the austenitization temperature, which are found to deliver significant variations in hardness. Partial-transformation experiments are used to show the development of microstructure in segregated material. Evidence is presented which indicates the bulk microstructure is not one of upper bainite, as it has been described in the past, but one comprised of Widmanstätten ferrite and pockets of lower bainite. Segregation is observed on three different length scales, and the origins of each type are proposed. Suggestions are put forward for how the segregation might be minimized, and its detrimental effects suppressed by heat treatments.

  19. Continuous Cooling Transformations in Nuclear Pressure Vessel Steels

    Science.gov (United States)

    Pous-Romero, Hector; Bhadeshia, Harry K. D. H.

    2014-10-01

    A class of low-alloy steels often referred to as SA508 represent key materials for the manufacture of nuclear reactor pressure vessels. The alloys have good properties, but the scatter in properties is of prime interest in safe design. Such scatter can arise from microstructural variations but most studies conclude that large components made from such steels are, following heat treatment, fully bainitic. In the present work, we demonstrate with the help of a variety of experimental techniques that the microstructures of three SA508 Gr.3 alloys are far from homogeneous when considered in the context of the cooling rates encountered in practice. In particular, allotriomorphic ferrite that is expected to lead to a deterioration in toughness, is found in the microstructure for realistic combinations of austenite grain size and the cooling rate combination. Parameters are established to identify the domains in which SA508 Gr.3 steels transform only into the fine bainitic microstructures.

  20. Multipurpose Pressure Vessel Scanner and Photon Doppler Velocimetry

    Science.gov (United States)

    Ellis, Tayera

    2015-01-01

    Critical flight hardware typically undergoes a series of nondestructive evaluation methods to screen for defects before it is integrated into the flight system. Conventionally, pressure vessels have been inspected for flaws using a technique known as fluorescent dye penetrant, which is biased to inspector interpretation. An alternate method known as eddy current is automated and can detect small cracks better than dye penetrant. A new multipurpose pressure vessel scanner has been developed to perform internal and external eddy current scanning, laser profilometry, and thickness mapping on pressure vessels. Before this system can be implemented throughout industry, a probability of detection (POD) study needs to be performed to validate the system’s eddy current crack/flaw capabilities. The POD sample set will consist of 6 flight-like metal pressure vessel liners with defects of known size. Preparation for the POD includes sample set fabrication, system operation, procedure development, and eddy current settings optimization. For this, collaborating with subject matter experts was required. This technical paper details the preparation activities leading up to the POD study currently scheduled for winter 2015/2016. Once validated, this system will be a proven innovation for increasing the safety and reliability of necessary flight hardware.Additionally, testing of frangible joint requires Photon Doppler Velocimetry (PDV) and Digital Image Correlation instrumentation. There is often noise associated with PDV data, which necessitates a frequency modulation (FM) signal-to-noise pre-test. Generally, FM radio works by varying the carrier frequency and mixing it with a fixed frequency source, creating a beat frequency which is represented by audio frequency that can be heard between about 20 to 20,000 Hz. Similarly, PDV reflects a shifted frequency (a phenomenon known as the Doppler Effect) from a moving source and mixes it with a fixed source frequency, which results in

  1. D-Zero Central Calorimeter Pressure Vessel and Vacuum Vessel Safety Notes

    Energy Technology Data Exchange (ETDEWEB)

    Rucinski, R.; Luther, R.; /Fermilab

    1990-10-25

    The relief valve and relief piping capacity was calculated to be 908 sefm air. This exceeds all relieving conditions. The vessel also has a rupture disc with a 2640 scfm air stamped capacity. In order to significantly decrease the amount of time required to fill the cryostats, it is desired to raise the setpoint of the 'operating' relief valve on the argon storage dewar to 20 psig from its existing 16 psig setting. This additional pressure increases the flow to the cryostats and will overwhelm the relief capacity if the temperature of the modules within these vessels is warm enough. Using some conservative assumptions and simple calculations within this note, the maximum average temperature that the modules within each cryostat can be at prior to filling from the storage dewar with liquid argon is at least 290 K. The average temperature of the module mass for any of the three cryostats can be as high as 290 K prior to filling that particular cryostat. This should not be confused with the average temperature of a single type or location which is useful in protecting the modules-not necessarily the vessel itself. A few modules of each type and at different elevations should be used in an average which would account for the different weights of each module. Note that at 290 K, the actual flow of argon through the relief valve and the rupture disk was under the maximum theoretical flows for each relief device. This means that the bulk temperature could actually have been raised to flow argon through the reliefs at their maximum capacity. Therefore, the temperature of 290 K is a conservative value for the calculated flow rate of 12.3 gpm. Safeguards in addition to and used in conjunction with operating procedures shall be implemented in such a way so that the above temperature limitation is not exceeded and such that it is exclusive of the programmable logic controller (PLC). One suggestion is using a toggle switch for each cryostat mounted in the PLC I/O box

  2. Performance Evaluation Tests of Insulated Pressure Vessels for Vehicular Hydrogen Storage

    Energy Technology Data Exchange (ETDEWEB)

    Aceves, S M; Martinez-Frias, J; Espinoza-Loza, F

    2002-03-01

    Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen or ambient-temperature compressed hydrogen. This flexibility results in multiple advantages with respect to compressed hydrogen tanks or low-pressure liquid hydrogen tanks. Our work is directed at verifying that commercially available aluminum-lined, fiber-wrapped pressure vessels can be safely used to store liquid hydrogen. A series of tests have been conducted, and the results indicate that no significant vessel damage has resulted from cryogenic operation. Future activities include a demonstration project in which the insulated pressure vessels will be installed and tested on two vehicles. A draft standard will also be generated for certification of insulated pressure vessels.

  3. Support device in a pressure vessel, particularly a reactor pressure vessel, to support against horizontal forces. Abstuetzeinrichtung an einem Druckbehaelter, insbesondere einem Reaktordruckbehaelter, gegen Horizontalkraefte

    Energy Technology Data Exchange (ETDEWEB)

    Dorner, H.; Harand, E.; Scholz, M.; Scheler, R.

    1986-04-17

    In a support device on a reactor pressure vessel of a PWR, a guide leading downwards is provided in the vertical pellet cartridge on the floor side of the reactor pressure vessel, which is located in a fixed support pipe. The support pipe is supported on a concreted baseplate in the horizontal direction, and can be screwed to this. The support pipe has a plate-shaped support foot to support it on the baseplate. The reactor pressure vessel, normally resting on its main coolant duct in the plane normal to the axis, can be effectively supported against horizontal forces by this additional support, without preventing thermal movement in the longitudinal axis.

  4. Insulated Pressure Vessels for Vehicular Hydrogen Storage: Analysis and Performance Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Aceves, S M; Martinez-Frias, J; Garcia-Villazana, O; Espinosa-Loza, F

    2001-06-26

    Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen (LH{sub 2}) or ambient-temperature compressed hydrogen (CH{sub 2}). Insulated pressure vessels offer the advantages of liquid hydrogen tanks (low weight and volume), with reduced disadvantages (fuel flexibility, lower energy requirement for hydrogen liquefaction and reduced evaporative losses). The work described here is directed at verifying that commercially available pressure vessels can be safely used to store liquid hydrogen. The use of commercially available pressure vessels significantly reduces the cost and complexity of the insulated pressure vessel development effort. This paper describes a series of tests that have been done with aluminum-lined, fiber-wrapped vessels to evaluate the damage caused by low temperature operation. All analysis and experiments to date indicate that no significant damage has resulted. Required future tests are described that will prove that no technical barriers exist to the safe use of aluminum-fiber vessels at cryogenic temperatures. Future activities also include a demonstration project in which the insulated pressure vessels will be installed and tested on two vehicles. A draft standard will also be generated for obtaining certification for insulated pressure vessels.

  5. Performance and Certification Testing of Insulated Pressure Vessels for Vehicular Hydrogen Storage

    Energy Technology Data Exchange (ETDEWEB)

    Aceves, S M; Martinez-Frias, J; Garcia-Villazana, O; Espinosa-Loza, F

    2001-06-03

    Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen (LH2) or ambient-temperature compressed hydrogen (CH2). Insulated pressure vessels offer the advantages of liquid hydrogen tanks (low weight and volume), with reduced disadvantages (fuel flexibility, lower energy requirement for hydrogen liquefaction and reduced evaporative losses). The work described here is directed at verifying that commercially available pressure vessels can be safely used to store liquid hydrogen. The use of commercially available pressure vessels significantly reduces the cost and complexity of the insulated pressure vessel development effort. This paper describes a series of tests that have been done with aluminum-lined, fiber-wrapped vessels to evaluate the damage caused by low temperature operation. All analysis and experiments to date indicate that no significant damage has resulted. Required future tests are described that will prove that no technical barriers exist to the safe use of aluminum-fiber vessels at cryogenic temperatures. Future activities also include a demonstration project in which the insulated pressure vessels will be installed and tested on two vehicles. A draft standard will also be generated for obtaining certification for insulated pressure vessels.

  6. Compositional attribution of non-provenienced Maya polychrome vessels

    Energy Technology Data Exchange (ETDEWEB)

    Bishop, R.L.; Harbottle, G.; Reents, D.J.; Sayre, E.V.; van Zelst, L.

    1983-01-01

    Procedures and a few of the results of the Maya ceramic project are discussed from the perspective of non-provenienced vessel attribution ranging from site specific through a more inferential level to the rather hypothetical. The examples presented serve to illustrate the manner in which compositional and stylistic covariation are viewed in an investigation of Maya Ceramic art. The large data base from neutron activation analysis including archaeologically recovered pottery as well as the stylistically and iconographically elaborate vessels requires continued refinement in our methods of statistical analysis along with gaining a greater understanding of the sources of ceramic compositional variation in the Maya area. The mutually beneficial collaboration between science, art, and archaeology are emphasized.

  7. Finite element analysis to estimate burst pressure of mild steel pressure vessel using Ramberg–Osgood model

    OpenAIRE

    Deolia, Puneet; Firoz A. Shaikh

    2016-01-01

    Burst pressure is the pressure at which vessel burst/crack and internal fluid leaks. An accurate prediction of burst pressure is necessary in chemical, medical and aviation industry. Burst pressure is a design safety limit, which should not be exceeded. If this pressure is exceeded it may lead to the mechanical breach and permanent loss of pressure containment. So burst pressure calculation is necessary for all the critical applications. To numerically calculate burst pressure material curve ...

  8. Modelling of pressure increase protection system for the vacuum vessel of W7-X device

    Energy Technology Data Exchange (ETDEWEB)

    Kaliatka, Tadas, E-mail: tadas.kaliatka@lei.lt; Uspuras, Eugenijus; Kaliatka, Algirdas

    2016-11-01

    Highlights: • Two in-vessel LOCAs (partial and guillotine break of 40 mm diameter pipe of cooling system) for Wendelstein 7-X fusion device were analyzed. • The analysis of the processes in the cooling system, vacuum vessel and pressure increase protection system were performed using thermal-hydraulic RELAP5 Mod3.3 code. • The suitability of pressure increase protection system was assessed. - Abstract: In fusion devices, plasma is contained in a vacuum vessel. The vacuum vessel cannot withstand a pressure above atmospheric. Any damage of in-vessel components could lead to water ingress and may lead to pressure increase and possible damage of vacuum vessel. In order to avoid such undesirable consequences, the pressure increase protection system is designed. In this article, the processes occurring in the vacuum vessel and pressure increase protection system of W7-X device during LOCA (small and guillotine pipe break) event are analyzed. The model of W7-X cooling system, vacuum vessel and pressure increase protection system was developed using RELAP5 code. Numerical analysis of partial and guillotine break of 40 mm diameter pipe of cooling system was performed. Calculation results showed that burst disc of the pressure increase protection system does not open when the cross section area of partial break in the cooling system is smaller than 1 mm{sup 2}. During the guillotine break of cooling system, the burst disc opens, but pressure increase protection system is capable to prevent overpressure of the vacuum vessel.

  9. Tensile and Fatigue Behavior of ASS304 for Cold Stretching Pressure Vessels at Cryogenic Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hoon Seok [The 5th R and D Institute, Agency for Defense Development, Daejeon (Korea, Republic of); Kim, Jae Hoon; Na, Seong Hyun [Chungnam National Univ., Daejon (Korea, Republic of); Lee, Youn Hyung [Korean Gas Safety Corporation, Chungju (Korea, Republic of); Kim, Sung Hun [Daechang Solution Co. Ltd, Busan (Korea, Republic of); Kim, Young Kyun; Kim, Ki Dong [Korean Gas Corporation, R and D Division, Ansan (Korea, Republic of)

    2016-05-15

    Cold stretching(CS) pressure vessels from ASS304 (austenitic stainless steel 304) are used for the transportation and storage of liquefied natural gas(LNG). CS pressure vessels are manufactured by pressurizing the finished vessels to a specific pressure to produce the required stress σk. After CS, there is some degree of plastic deformation. Therefore, CS vessels have a higher strength and lighter weight compared to conventional vessels. In this study, we investigate the tensile and fatigue behavior of ASS304 sampled by CS pressure vessels in accordance with the ASME code at cryogenic temperature. From the fatigue test results, we show S-N curves using a statistical method recommended by JSEM-S002. We carried out the fractography of fractured specimens using scanning electron microscopy (SEM)

  10. Fabrication Flaw Density and Distribution In Repairs to Reactor Pressure Vessel and Piping Welds

    Energy Technology Data Exchange (ETDEWEB)

    GJ Schuster, FA Simonen, SR Doctor

    2008-04-01

    The Pacific Northwest National Laboratory is developing a generalized fabrication flaw distribution for the population of nuclear reactor pressure vessels and for piping welds in U.S. operating reactors. The purpose of the generalized flaw distribution is to predict component-specific flaw densities. The estimates of fabrication flaws are intended for use in fracture mechanics structural integrity assessments. Structural integrity assessments, such as estimating the frequency of loss-of-coolant accidents, are performed by computer codes that require, as input, accurate estimates of flaw densities. Welds from four different reactor pressure vessels and a collection of archived pipes have been studied to develop empirical estimates of fabrication flaw densities. This report describes the fabrication flaw distribution and characterization in the repair weld metal of vessels and piping. This work indicates that large flaws occur in these repairs. These results show that repair flaws are complex in composition and sometimes include cracks on the ends of the repair cavities. Parametric analysis using an exponential fit is performed on the data. The relevance of construction records is established for describing fabrication processes and product forms. An analysis of these records shows there was a significant change in repair frequency over the years when these components were fabricated. A description of repair flaw morphology is provided with a discussion of fracture mechanics significance. Fabrication flaws in repairs are characterized using optimized-access, high-sensitivity nondestructive ultrasonic testing. Flaw characterizations are then validated by other nondestructive evaluation techniques and complemented by destructive testing.

  11. Creep of A508/533 Pressure Vessel Steel

    Energy Technology Data Exchange (ETDEWEB)

    Richard Wright

    2014-08-01

    ABSTRACT Evaluation of potential Reactor Pressure Vessel (RPV) steels has been carried out as part of the pre-conceptual Very High Temperature Reactor (VHTR) design studies. These design studies have generally focused on American Society of Mechanical Engineers (ASME) Code status of the steels, temperature limits, and allowable stresses. Initially, three candidate materials were identified by this process: conventional light water reactor (LWR) RPV steels A508 and A533, 2¼Cr-1Mo in the annealed condition, and Grade 91 steel. The low strength of 2¼Cr-1Mo at elevated temperature has eliminated this steel from serious consideration as the VHTR RPV candidate material. Discussions with the very few vendors that can potentially produce large forgings for nuclear pressure vessels indicate a strong preference for conventional LWR steels. This preference is based in part on extensive experience with forging these steels for nuclear components. It is also based on the inability to cast large ingots of the Grade 91 steel due to segregation during ingot solidification, thus restricting the possible mass of forging components and increasing the amount of welding required for completion of the RPV. Grade 91 steel is also prone to weld cracking and must be post-weld heat treated to ensure adequate high-temperature strength. There are also questions about the ability to produce, and very importantly, verify the through thickness properties of thick sections of Grade 91 material. The availability of large components, ease of fabrication, and nuclear service experience with the A508 and A533 steels strongly favor their use in the RPV for the VHTR. Lowering the gas outlet temperature for the VHTR to 750°C from 950 to 1000°C, proposed in early concept studies, further strengthens the justification for this material selection. This steel is allowed in the ASME Boiler and Pressure Vessel Code for nuclear service up to 371°C (700°F); certain excursions above that temperature are

  12. Fatigue crack growth behavior of pressure vessel steels and submerged arc weldments in a high-temperature pressurized water environment

    Science.gov (United States)

    Liaw, P. K.; Logsdon, W. A.; Begley, J. A.

    1989-10-01

    The fatigue crack growth rate (FCGR) properties of SA508 C1 2a and SA533 Gr A C1 2 pressure vessel steels and the corresponding automatic submerged are weldments were developed in a high-temperature pressurized water (HPW) environment at 288 °C (550°F) and 7.2 MPa (1044 psi) at load ratios of 0.02 and 0.50. The HPW enviromment FCGR properties of these pressure vessel steels and submerged arc weldments were generally conservative, compared with the approrpriate American Society of Mechanical Engineers (ASME) Section XI water environmental reference curve. The growth rate of fatigue cracks in the base materials, however, was considerably faster in the HPW environment than in a corresponding 288°C (550°F) base line air environment. The growth rate of fatigue cracks in the two submerged are weldments was also accelerated in the HPW environment but to a significantly lesser degree than that demonstrated by the corresponding base materials. In the air environment, fatigue striations were observed, independent of material and load ratio, while in the HPW environment, some intergranular facets were present. The greater environmental effect on crack growth rates displayed by the base materials, as compared with the weldments, was attributed to a different sulfide composition and morphology.

  13. Fracture Analysis of Rubber Sealing Material for High Pressure Hydrogen Vessel

    National Research Council Canada - National Science Library

    YAMABE, Junichiro; FUJIWARA, Hirotada; NISHIMURA, Shin

    2011-01-01

    In order to clarify the influence of high pressure hydrogen gas on mechanical damage in a rubber O-ring, the fracture analysis of the O-ring used for a sealing material of a pressure hydrogen vessel was conducted...

  14. Optical Sensing using Fiber Bragg Gratings for Monitoring Structural Damage in Composite Over-Wrapped Vessels

    Science.gov (United States)

    Grant, Joseph

    2005-01-01

    Composite Over-Wrap Vessels are widely used in the aerospace community. They are made of thin-walled bottles that are over wrapped with high strength fibers embedded in a matrix material. There is a strong drive to reduce the weight of space borne vehicles and thus pushes designers to adopt COPVs that are over wrapped with graphite fibers embedded in its epoxy matrix. Unfortunately, this same fiber-matrix configuration is more susceptible to impact damage than others and to make matters worse; there is a regime where impacts that damage the over wrap leave no visible scar on the COPV surface. In this paper FBG sensors are presented as a means of monitoring and detecting these types of damage. The FBG sensors are surface mounted to the COPVs and optically interrogated to explore the structural properties of these composite pressure vessels. These gratings optically inscribed into the core of a single mode fiber are used as a tool to monitor the stress strain relation in the composite matrix. The response of these fiber-optic sensors is investigated by pressurizing the cylinder up to its burst pressure of around 4500 psi. A Fiber Optic Demodulation System built by Blue Road Research, is used for interrogation of the Bragg gratings.

  15. ITER cryostat main chamber and vacuum vessel pressure suppression system design

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Akira; Nakahira, Masataka; Takahashi, Hiroyuki; Tada, Eisuke [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Nakashima, Yoshitane; Ueno, Osamu

    1999-03-01

    Design of Cryostat Main Chamber and Vacuum Vessel Pressure Suppression System (VVPS) of International Thermonuclear Experimental Reactor (ITER) has been conducted. The cryostat is a cylindrical vessel that includes in-vessel component such as vacuum vessel, superconducting toroidal coils and poloidal coils. This cryostat provides the adiabatic vacuum about 10{sup -4} Pa for the superconducting coils operating at 4 K and forms the second confinement barrier to tritium. The adiabatic vacuum is to reduce thermal loads applied to the superconducting coils and their supports so as to keep their temperature 4 K. The VVPS consists of a suppression tank located under the lower bio-shield and 4 relief pipes to connect the vacuum vessel and the suppression tank. The VVPS is to keep the maximum pressure rise of the vacuum vessel below the design value of 0.5 MPa in case of the in-vessel LOCA (water spillage from in-vessel component). The spilled water and steam are lead to the suppression tank through the relief pipes when the internal pressure of vacuum vessel is over 0.2 MPa, and then the internal pressure is kept below 0.5 MPa. This report summarizes the structural design of the cryostat main chamber and pressure suppression system, together with their fabrication and installation. (author)

  16. Embrittlement recovery due to annealing of reactor pressure vessel steels

    Energy Technology Data Exchange (ETDEWEB)

    Eason, E.D.; Wright, J.E.; Nelson, E.E. [Modeling and Computing Services, Boulder, CO (United States); Odette, G.R.; Mader, E.V. [Univ. of California, Santa Barbara, CA (United States)

    1996-03-01

    Embrittlement of reactor pressure vessels (RPVs) can be reduced by thermal annealing at temperatures higher than the normal operating conditions. Although such an annealing process has not been applied to any commercial plants in the United States, one US Army reactor, the BR3 plant in Belgium, and several plants in eastern Europe have been successfully annealed. All available Charpy annealing data were collected and analyzed in this project to develop quantitative models for estimating the recovery in 30 ft-lb (41 J) Charpy transition temperature and Charpy upper shelf energy over a range of potential annealing conditions. Pattern recognition, transformation analysis, residual studies, and the current understanding of the mechanisms involved in the annealing process were used to guide the selection of the most sensitive variables and correlating parameters and to determine the optimal functional forms for fitting the data. The resulting models were fitted by nonlinear least squares. The use of advanced tools, the larger data base now available, and insight from surrogate hardness data produced improved models for quantitative evaluation of the effects of annealing. The quality of models fitted in this project was evaluated by considering both the Charpy annealing data used for fitting and the surrogate hardness data base. The standard errors of the resulting recovery models relative to calibration data are comparable to the uncertainty in unirradiated Charpy data. This work also demonstrates that microhardness recovery is a good surrogate for transition temperature shift recovery and that there is a high level of consistency between the observed annealing trends and fundamental models of embrittlement and recovery processes.

  17. Probabilistic Structural Integrity Analysis of Boiling Water Reactor Pressure Vessel under Low Temperature Overpressure Event

    Directory of Open Access Journals (Sweden)

    Hsoung-Wei Chou

    2015-01-01

    Full Text Available The probabilistic structural integrity of a Taiwan domestic boiling water reactor pressure vessel has been evaluated by the probabilistic fracture mechanics analysis. First, the analysis model was built for the beltline region of the reactor pressure vessel considering the plant specific data. Meanwhile, the flaw models which comprehensively simulate all kinds of preexisting flaws along the vessel wall were employed here. The low temperature overpressure transient which has been concluded to be the severest accident for a boiling water reactor pressure vessel was considered as the loading condition. It is indicated that the fracture mostly happens near the fusion-line area of axial welds but with negligible failure risk. The calculated results indicate that the domestic reactor pressure vessel has sufficient structural integrity until doubling of the present end-of-license operation.

  18. The evaluation of pressure effects on the ex-vessel cooling for KNGR with MELCOR

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Hwa; Park, Soo Yong; Kim, Dong Ha

    2001-03-01

    In this report, the effect of external vessel cooling on debris coolability and vessel integrity for the KNGR were examined from the two typical pressure range of high(170 bar) and low(5 bar)case using the lower plenum model in MELCOR1.8.4. As the conditions of these calculations, 80 ton of debris was relocated simultaneously into the lower vessel head and the debris relocation temperature from the core region was 2700 K. The decay heat has been assumed to be that of one hour after reactor shutdown. The creep failure of the vessel wall was simulated with 1-D model, which can consider the rapid temperature gradient over the wall thickness during the ex-vessel cooling. From the calculation results, both the coolant temperature and the total amount of coolant mass injected into the cavity are known to be the important factors in determining the time period to keep the external vessel cool. Therefore, a long-term strategy to keep the coolant temperature subcooled throughout the transient is suggested to sustain or prolong the effect of external vessel cooling. Also, it is expected that to keep the primary side at low pressure and to perform the ex-vessel flooding be the essential conditions to sustain the vessel integrity. From MELCOR, the penetration failure always occurs after relocation regardless of the RCS pressure or availability of the external vessel cooling. Therefore, It is expected that the improvement of the model for the penetration tube failure will be necessary.

  19. The influence of chemistry concentration on the fracture risk of a reactor pressure vessel subjected to pressurized thermal shocks

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Pin-Chiun [Institute of Nuclear Engineering and Science, National Tsing-Hua University, Hsinchu 30013, Taiwan, ROC (China); Chou, Hsoung-Wei, E-mail: hwchou@iner.gov.tw [Institute of Nuclear Energy Research, Taoyuan 32546, Taiwan, ROC (China); Ferng, Yuh-Ming [Institute of Nuclear Engineering and Science, National Tsing-Hua University, Hsinchu 30013, Taiwan, ROC (China)

    2016-02-15

    Highlights: • Probabilistic fracture mechanics method was used to analyze a reactor pressure vessel. • Effects of copper and nickel contents on RPV fracture probability under PTS were investigated and discussed. • Representative PTS transients of Beaver Valley nuclear power plant were utilized. • The range of copper and nickel contents of the RPV materials were suggested. • With different embrittlement levels the dominated PTS category is different. - Abstract: The radiation embrittlement behavior of reactor pressure vessel shell is influenced by the chemistry concentration of metal materials. This paper aims to study the effects of copper and nickel content variations on the fracture risk of pressurized water reactor (PWR) pressure vessel subjected to pressurized thermal shock (PTS) transients. The probabilistic fracture mechanics (PFM) code, FAVOR, which was developed by the Oak Ridge National Laboratory in the United States, is employed to perform the analyses. A Taiwan domestic PWR pressure vessel assumed with varied copper and nickel contents of beltline region welds and plates is investigated in the study. Some PTS transients analyzed from Beaver Valley Unit 1 for establishing the U.S. NRC's new PTS rule are applied as the loading condition. It is found that the content variation of copper and nickel will significantly affect the radiation embrittlement and the fracture probability of PWR pressure vessels. The results can be regarded as the risk incremental factors for comparison with the safety regulation requirements on vessel degradation as well as a reference for the operation of PWR plants in Taiwan.

  20. Current Status of Development of High Nickel Low Alloy Steels for Commercial Reactor Pressure Vessel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min Chul; Lee, B. S.; Park, S. G.; Lee, K. H. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2008-12-15

    SA508 Gr.3 Mn-Mo-Ni low alloy steels have been used for nuclear reactor pressure vessel steels up to now. Currently, the design goal of nuclear power plant is focusing at larger capacity and longer lifetime. Requirements of much bigger pressure vessels may cause critical problems in the manufacturing stage as well as for the welding stage. Application of higher strength steel may be required to overcome the technical problems. It is known that a higher strength and fracture toughness of low alloy steels such as SA508 Gr.4N low alloy steel could be achieved by increasing the Ni and Cr contents. Therefore, SA508 Gr.4N low alloy steel is very attractive as eligible RPV steel for the next generation PWR systems. In this report, we propose the possibility of SA508 Gr.4N low alloy steel for an application of next generation commercial RPV, based on the literature research result about development history of the RPV steels and SA508 specification. In addition, we have surveyed the research result of HSLA(High Strength Low Alloy steel), which has similar chemical compositions with SA508 Gr.4N, to understand the problems and the way of improvement of SA508 Gr.4N low alloy steel. And also, we have investigated eastern RPV steel(WWER-1000), which has higher Ni contents compared to western RPV steel.

  1. A quick guide to API 510 certified pressure vessel inspector syllabus example questions and worked answers

    CERN Document Server

    Matthews, Clifford

    2010-01-01

    The API Individual Certification Programs (ICPs) are well established worldwide in the oil, gas, and petroleum industries. This Quick Guide is unique in providing simple, accessible and well-structured guidance for anyone studying the API 510 Certified Pressure Vessel Inspector syllabus by summarizing and helping them through the syllabus and providing multiple example questions and worked answers.Technical standards are referenced from the API 'body of knowledge' for the examination, i.e. API 510 Pressure vessel inspection, alteration, rerating; API 572 Pressure vessel inspection; API

  2. 77 FR 23513 - Updated Aging Management Criteria for Reactor Vessel Internal Components of Pressurized Water...

    Science.gov (United States)

    2012-04-19

    ... COMMISSION Updated Aging Management Criteria for Reactor Vessel Internal Components of Pressurized Water... Management Criteria for PWR Reactor Vessel Internal Components.'' The original notice provided the ADAMS... published a notice requesting public comments on draft LR-ISG-2011-04, ``Updated Aging Management Criteria...

  3. Statistical analysis using the Bayesian nonparametric method for irradiation embrittlement of reactor pressure vessels

    Science.gov (United States)

    Takamizawa, Hisashi; Itoh, Hiroto; Nishiyama, Yutaka

    2016-10-01

    In order to understand neutron irradiation embrittlement in high fluence regions, statistical analysis using the Bayesian nonparametric (BNP) method was performed for the Japanese surveillance and material test reactor irradiation database. The BNP method is essentially expressed as an infinite summation of normal distributions, with input data being subdivided into clusters with identical statistical parameters, such as mean and standard deviation, for each cluster to estimate shifts in ductile-to-brittle transition temperature (DBTT). The clusters typically depend on chemical compositions, irradiation conditions, and the irradiation embrittlement. Specific variables contributing to the irradiation embrittlement include the content of Cu, Ni, P, Si, and Mn in the pressure vessel steels, neutron flux, neutron fluence, and irradiation temperatures. It was found that the measured shifts of DBTT correlated well with the calculated ones. Data associated with the same materials were subdivided into the same clusters even if neutron fluences were increased.

  4. Mechanical spectroscopy of reactor-pressure-vessel steel embrittlement: a progress report

    Energy Technology Data Exchange (ETDEWEB)

    Van Ouytsel, K

    1998-08-01

    An enhanced surveillance strategy for testing the fracture toughness of reactor-pressure-vessel steel embrittlement is described. Microstructural investigation in support of damage modelling is an essential element in this enhanced strategy. Temperature-dependent experiments are very sensitive to differences in chemical composition and to effects of neutron irradiation as well as thermal ageing. Amplitude-dependent experiments can be related to tensile test results and correspond to a model for the yield stress. A full range of experiments were carried out on base and weld metal from the Doel-I-II power plants. The results have indicated that internal friction yields information which cannot always be detected by means of standard testing techniques. An inverted torsion pendulum for measuring internal friction has been constructed.

  5. Adaptation of mesenteric lymphatic vessels to prolonged changes in transmural pressure.

    Science.gov (United States)

    Dongaonkar, R M; Nguyen, T L; Quick, C M; Hardy, J; Laine, G A; Wilson, E; Stewart, R H

    2013-07-15

    In vitro studies have revealed that acute increases in transmural pressure increase lymphatic vessel contractile function. However, adaptive responses to prolonged changes in transmural pressure in vivo have not been reported. Therefore, we developed a novel bovine mesenteric lymphatic partial constriction model to test the hypothesis that lymphatic vessels exposed to higher transmural pressures adapt functionally to become stronger pumps than vessels exposed to lower transmural pressures. Postnodal mesenteric lymphatic vessels were partially constricted for 3 days. On postoperative day 3, constricted vessels were isolated, and divided into upstream (UP) and downstream (DN) segment groups, and instrumented in an isolated bath. Although there were no differences between the passive diameters of the two groups, both diastolic diameter and systolic diameter were significantly larger in the UP group than in the DN group. The pump index of the UP group was also higher than that in the DN group. In conclusion, this is the first work to report how lymphatic vessels adapt to prolonged changes in transmural pressure in vivo. Our results suggest that vessel segments upstream of the constriction adapt to become both better fluid conduits and lymphatic pumps than downstream segments.

  6. Comparison of closed-pressurized and open-refluxed vessel ...

    African Journals Online (AJOL)

    Samples of residual fuel oil reference material (SRM 1634c) were mineralized in closed digestion vessels from Milestone Laboratory Systems (MLS) or from PAAR (HPA) or in open-refluxed microwave digestion flasks from Prolabo. The three digestion systems were evaluated in terms of accuracy and precision, reagents ...

  7. Numerical simulation of premixed Hydrogen/air combustion pressure in a spherical vessel

    OpenAIRE

    Guo Han-yu; Tao Gang; Zhang Li-jing

    2016-01-01

    In order to study the development process of hydrogen combustion in a closed vessel, an on-line chemical equilibrium calculator and a numerical simulation method would be used to analysis the combustion pressure and flame front of mixed gas, which based on 20L H2/air explosion experiments in spherical vessel (Crowl and Jo,2009). The results showed that, the turbulent model could reflect the process of combustion, and the error of combustion pressure by simulation is smaller than the Chemical ...

  8. Evaluation of detectable defect size for inner defect of pressure vessel using laser speckle

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyeoung Suk; Seon, Sang Woo; Choi, Tae Ho; Kang, Chan Geun; Na, Man Gyun; Jung, Hyun Chul [Chsoun University, Gwangju (Korea, Republic of)

    2014-04-15

    Pressure vessels are used in various industrial fields. If a defect occurs on the inner or outer surface of a pressure vessel, it may cause a massive accident. A defect on the outer surface can be detected by visual inspection. However, a defect on the inner surface is generally impossible to detect with visual inspection. Nondestructive testing can be used to detect this type of defect. Laser speckle shearing interferometry is one nondestructive testing method that can optically detect a defect; its advantages include noncontact, full field, and real time inspection. This study evaluated the detectable size for an internal defect of a pressure vessel. The material of the pressure vessel was ASTM A53 Gr.B. The internal defect was detected when the pressure vessel was loaded by internal pressure controlled by a pneumatic system. The internal pressure was controlled from 0.2 MPa to 0.6 MPa in increments of 0.2 MPa. The results confirmed that an internal defect with a 25 % defect depth could be detected even at 0.2 MPa pressure variation.

  9. Analytical and computational methodology to assess the over pressures generated by a potential catastrophic failure of a cryogenic pressure vessel

    Energy Technology Data Exchange (ETDEWEB)

    Zamora, I.; Fradera, J.; Jaskiewicz, F.; Lopez, D.; Hermosa, B.; Aleman, A.; Izquierdo, J.; Buskop, J.

    2014-07-01

    Idom has participated in the risk evaluation of Safety Important Class (SIC) structures due to over pressures generated by a catastrophic failure of a cryogenic pressure vessel at ITER plant site. The evaluation implements both analytical and computational methodologies achieving consistent and robust results. (Author)

  10. Hot cell examination on the surveillance capsule of SA 533 cl. 1 reactor pressure vessel (1st test report)

    Energy Technology Data Exchange (ETDEWEB)

    Choo, Yong Sun; Jung, Y. H.; Yoo, B. O.; Baik, S. J.; Oh, W. H.; Soong, W. S.; Hong, K. P

    2000-08-01

    The post-irradiated examinations such as impact test, tensile test, composition analysis and etc. were conducted to monitor and to evaluate the radiation-induced changes, so called radiation embrittlement, in the mechanical properties of ferritic materials. Those data should be applied to confirm safety as well as reliability of reactor pressure vessel. The scopes and contents of hot cell examination on the surveillance capsule are as follows; - Capsule transportation, cutting, dismantling and classification - Shim block and Dosimeter cutting and dismantling - Impact test - Tensile test - Composition analysis by EPMA - SEM observation on the fractured surface - Hardness test - Radwaste treatment.

  11. Non-Intrusive Inspection (NII) of pressure vessels

    OpenAIRE

    Eriksson, Andreas

    2015-01-01

    Master's thesis in Offshore technology : industrial asset management The aim of this thesis is to identify and recommend vessels that are suitable for inspection according the NII methodology, DNV-RP-G103. The theoretical guideline used during the analysis, DNV-RP-G103, was chosen since it is the acknowledged and recommended standard in the inspection industry, and it is also according to internal technical requirements in Statoil ASA. The thesis also includes a cost benefit assessment and...

  12. Non-Axisymmetric Inflatable Pressure Structure (NAIPS) Concept that Enables Mass Efficient Packageable Pressure Vessels with Sealable Openings

    Science.gov (United States)

    Doggett, William R.; Jones, Thomas C.; Kenner, Winfred S.; Moore, David F.; Watson, Judith J.; Warren, Jerry E.; Makino, Alberto; Yount, Bryan; Selig, Molly; Shariff, Khadijah; hide

    2016-01-01

    Achieving minimal launch volume and mass are always important for space missions, especially for deep space manned missions where the costs required to transport mass to the destination are high and volume in the payload shroud is limited. Pressure vessels are used for many purposes in space missions including habitats, airlocks, and tank farms for fuel or processed resources. A lucrative approach to minimize launch volume is to construct the pressure vessels from soft goods so that they can be compactly packaged for launch and then inflated en route or at the final destination. In addition, there is the potential to reduce system mass because the packaged pressure vessels are inherently robust to launch loads and do not need to be modified from their in-service configuration to survive the launch environment. A novel concept is presented herein, in which sealable openings or hatches into the pressure vessels can also be fabricated from soft goods. To accomplish this, the structural shape is designed to have large regions where one principal stress is near zero. The pressure vessel is also required to have an elongated geometry for applications such as airlocks.

  13. Final Report of the 2nd Ex-Vessel Neutron Dosimetry Installation And Evaluations for Kori Unit 1 Reactor Pressure Vessel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Byoung Chul; Yoo, Choon Sung; Lee, Sam Lai; Chang, Kee Ok; Gong, Un Sik; Choi, Kwon Jae; Chang, Jong Hwa; Kim, Kwan Hyun; Hong, Joon Wha

    2007-02-15

    This report describes a neutron fluence assessment performed for the Kori Unit 1 pressure vessel beltline region based on the guidance specified in Regulatory Guide 1.190. In this assessment, maximum fast neutron exposures expressed in terms of fast neutron fluence (E>1 MeV) and iron atom displacements (dpa) were established for the beltline region of the pressure vessel. After Cycle 22 of reactor operation, 2nd Ex-Vessel Neutron Dosimetry Program was instituted at Kori Unit 1 to provide continuous monitoring of the beltline region of the reactor vessel. The use of the Ex-Vessel Neutron Dosimetry Program coupled with available surveillance capsule measurements provides a plant specific data base that enables the evaluation of the vessel exposure and the uncertainty associated with that exposure over the service life of the unit. Ex-Vessel Neutron Dosimetry has been evaluated at the conclusion of Cycle 23.

  14. Final report for the 2nd Ex-Vessel Neutron Dosimetry Installations and Evaluations for Yonggwang Unit 2 Reactor Pressure Vessel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Byoung Chul; Yoo, Choon Sung; Lee, Sam Lai; Gong, Un Sik; Choi, Kwon Jae; Chung, Kyoung Ki; Kim, Kwan Hyun; Chang, Jong Hwa; Ha, Jea Ju

    2008-01-15

    This report describes a neutron fluence assessment performed for the Yonggwang Unit 2 pressure vessel beltline region based on the guidance specified in Regulatory Guide 1.190. In this assessment, maximum fast neutron exposures expressed in terms of fast neutron fluence (E>1 MeV) and iron atom displacements (dpa) were established for the beltline region of the pressure vessel. During Cycle 16 of reactor operation, an Ex-Vessel Neutron Dosimetry Program was instituted at Yonggwang Unit 2 to provide continuous monitoring of the beltline region of the reactor vessel. The use of the Ex-Vessel Neutron Dosimetry Program coupled with available surveillance capsule measurements provides a plant specific data base that enables the evaluation of the vessel exposure and the uncertainty associated with that exposure over the service life of the unit. Ex-Vessel Neutron Dosimetry has been evaluated at the conclusion of Cycle 16.

  15. Final report for the 3rd Ex-Vessel Neutron Dosimetry Installations and Evaluations for Kori Unit 1 Reactor Pressure Vessel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Byoung Chul; Yoo, Choon Sung; Lee, Sam Lai (and others)

    2008-03-15

    This report describes a neutron fluence assessment performed for the Kori Unit 1 pressure vessel belt line region based on the guidance specified in Regulatory Guide 1.190. In this assessment, maximum fast neutron exposures expressed in terms of fast neutron fluence (E>1 MeV) and iron atom displacements (dpa) were established for the belt line region of the pressure vessel. After Cycle 23 of reactor operation, 3rd Ex-Vessel Neutron Dosimetry Program was instituted at Kori Unit 1 to provide continuous monitoring of the belt line region of the reactor vessel. The use of the Ex-Vessel Neutron Dosimetry Program coupled with available surveillance capsule measurements provides a plant specific data base that enables the evaluation of the vessel exposure and the uncertainty associated with that exposure over the service life of the unit. Ex-Vessel Neutron Dosimetry has been evaluated at the conclusion of Cycle 24.

  16. Final report for the 1st ex-vessel neutron dosimetry installations and evaluations for Kori unit 2 reactor pressure vessel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Byoung Chul; Yoo, Choon Sung; Lee, Sam Lai; Chang, Kee Ok; Gong, Un Sik; Choi, Kwon Jae; Chang, Jong Hwa; Lim, Nam Jin; Hong, Joon Wha; Cheon, Byeong Jin

    2006-11-15

    This report describes a neutron fluence assessment performed for the Kori unit 2 pressure vessel belt line region based on the guidance specified in regulatory guide 1.190. In this assessment, maximum fast neutron exposures expressed in terms of fast neutron fluence (E>1 MeV) and iron atom displacements (dpa) were established for the belt line region of the pressure vessel. During cycle 20 of reactor operation, an ex-vessel neutron dosimetry program was instituted at Kori unit 2 to provide continuous monitoring of the belt line region of the reactor vessel. The use of the ex-vessel neutron dosimetry program coupled with available surveillance capsule measurements provides a plant specific data base that enables the evaluation of the vessel exposure and the uncertainty associated with that exposure over the service life of the unit. Ex-vessel neutron dosimetry has been evaluated at the conclusion of cycle 20.

  17. Final Report of the 2nd Ex-Vessel Neutron Dosimetry Installation And Evaluations for Yonggwang Unit 1 Reactor Pressure Vessel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Byoung Chul; Yoo, Choon Sung; Lee, Sam Lai; Gong, Un Sik; Choi, Kwon Jae; Chung, Kyoung Ki; Kim, Kwan Hyun; Chang, Jong Hwa; Ha, Jea Ju

    2008-01-15

    This report describes a neutron fluence assessment performed for the Kori Unit 2 pressure vessel belt line region based on the guidance specified in Regulatory Guide 1.190. In this assessment, maximum fast neutron exposures expressed in terms of fast neutron fluence (E>1 MeV) and iron atom displacements (dpa) were established for the belt line region of the pressure vessel. During Cycle 21 of reactor operation, an Ex-Vessel Neutron Dosimetry Program was instituted at Kori Unit 2 to provide continuous monitoring of the belt line region of the reactor vessel. The use of the Ex-Vessel Neutron Dosimetry Program coupled with available surveillance capsule measurements provides a plant specific data base that enables the evaluation of the vessel exposure and the uncertainty associated with that exposure over the service life of the unit. Ex-Vessel Neutron Dosimetry has been evaluated at the conclusion of Cycle 21.

  18. Pressure and ion composition boundaries at Mars

    National Research Council Canada - National Science Library

    Xu, Shaosui; Liemohn, Michael W; Dong, Chuanfei; Mitchell, David L; Bougher, Stephen W; Ma, Yingjuan

    2016-01-01

    This study analyzes results from a multifluid MHD simulation to investigate the shape and structure of the pressure and composition boundaries at Mars, which can provide physical insight for the observational analysis...

  19. 77 FR 59408 - Finding of Equivalence; Alternate Pressure Relief Valve Settings on Certain Vessels Carrying...

    Science.gov (United States)

    2012-09-27

    ...] Finding of Equivalence; Alternate Pressure Relief Valve Settings on Certain Vessels Carrying Liquefied... announces the availability of CG-ENG Policy Letter 04-12, ``Alternative Pressure Relief Valve Settings on.... The higher stress factors lead to lower maximum allowable relief valve settings (MARVS) than are...

  20. A Dual Vessel System of Phosphating Ferrous Alloys under Steam Pressure

    Science.gov (United States)

    1979-08-01

    2. Manganese phosphate 5. Pressure process 3. Heat resistance 20. ABSTRACT fConfftiue MX r...success of pressure phosphating using consecutive produc- tion-type runs in the dual vessel system. For this manganese tartrate bath, 30% of the...recycling system is recommended for utilization of this process in the application of heavy manganese phosphate coatings to ferrous metal items. (U

  1. Uncertainties in risk assessment of hydrogen discharges from pressurized storage vessels at low temperatures

    DEFF Research Database (Denmark)

    Markert, Frank; Melideo, D.; Baraldi, D.

    2013-01-01

    20K) e.g. the cryogenic compressed gas storage covers pressures up to 35 MPa and temperatures between 33K and 338 K. Accurate calculations of high pressure releases require real gas EOS. This paper compares a number of EOS to predict hydrogen properties typical in different storage types. The vessel...

  2. The Effect of Localized Damage on the Electrical Conductivity of Bare Carbon Fiber Tow and its Use as a Non-Destructive Evaluation Tool for Composite Overwrapped Pressure Vessels

    Science.gov (United States)

    Wentzel, Daniel

    2015-01-01

    Composite materials are beneficial because of their high specific strength and low weight. Safety, Destructive testing and destructive testing, Non-Destructive Testing (NDT) and Non-Destructive Evaluation (NDE). Problem: Neither NDT nor NDE can provide sufficient data to determine life expectancy or quantify the damage state of a composite material.

  3. Pressure vessel made by free forming using underwater explosion

    OpenAIRE

    H Iyama; Maehara, H.; Hidaka, Y.; Itoh, S.

    2016-01-01

    Explosive forming is one particular forming technique, in which, mostcommonly, water is used as the pressure transmission medium. In recentyears, we have done the development of the method which obtains anecessary form of the metal by the control of underwater shock wave actson the metal plate, without a metal die. On the other hand, the pressurevessel is required in various fields, but we think that the free forming usingthe underwater shock wave is advantageous in the production of pressure...

  4. Effects of dynamic shear and transmural pressure on wall shear stress sensitivity in collecting lymphatic vessels.

    Science.gov (United States)

    Kornuta, Jeffrey A; Nepiyushchikh, Zhanna; Gasheva, Olga Y; Mukherjee, Anish; Zawieja, David C; Dixon, J Brandon

    2015-11-01

    Given the known mechanosensitivity of the lymphatic vasculature, we sought to investigate the effects of dynamic wall shear stress (WSS) on collecting lymphatic vessels while controlling for transmural pressure. Using a previously developed ex vivo lymphatic perfusion system (ELPS) capable of independently controlling both transaxial pressure gradient and average transmural pressure on an isolated lymphatic vessel, we imposed a multitude of flow conditions on rat thoracic ducts, while controlling for transmural pressure and measuring diameter changes. By gradually increasing the imposed flow through a vessel, we determined the WSS at which the vessel first shows sign of contraction inhibition, defining this point as the shear stress sensitivity of the vessel. The shear stress threshold that triggered a contractile response was significantly greater at a transmural pressure of 5 cmH2O (0.97 dyne/cm(2)) than at 3 cmH2O (0.64 dyne/cm(2)). While contraction frequency was reduced when a steady WSS was applied, this inhibition was reversed when the applied WSS oscillated, even though the mean wall shear stresses between the conditions were not significantly different. When the applied oscillatory WSS was large enough, flow itself synchronized the lymphatic contractions to the exact frequency of the applied waveform. Both transmural pressure and the rate of change of WSS have significant impacts on the contractile response of lymphatic vessels to flow. Specifically, time-varying shear stress can alter the inhibition of phasic contraction frequency and even coordinate contractions, providing evidence that dynamic shear could play an important role in the contractile function of collecting lymphatic vessels. Copyright © 2015 the American Physiological Society.

  5. Control Rod Drive Mechanism Installed in the Internal of Reactor Pressure Vessel

    Energy Technology Data Exchange (ETDEWEB)

    Choi, M. H.; Choi, S.; Park, J. S.; Lee, J. S.; Kim, D. O.; Hur, N. S.; Hur, H.; Yu, J. Y

    2008-09-15

    This report describes the review results and important technologies related to the in-vessel type control rod drive mechanism. Generally, most of the CRDMs used in the PWR are attached outside of the reactor pressure vessel, and the pernetration of the vessel head can not avoid. However, in-vessel type CRDMs, which are installed inside the reactor vessel, can eliminate the possibility of rod ejection accidents and the penetration of the vessel head, and provide a compact design of the reactor vessel and containment. There are two kinds of in-vessel type CRDM concerning the driving force-driven by a driving motor and by a hydraulic force. Motor driven CRDMs have been mainly investigated in Japan(MRX, IMR, DRX, next generation BWR etc.), and developed the key components such as a canned motor, an integrated rod position indicator, a separating ball-nut and a ball bearing that can operate under the water conditions of a high temperature and pressure. The concept of hydraulically driven CRDMs have been first reported by KWU and Siemens for KWU 200 reactor, and Argentina(CAREM) and China(NHR-5, NHR-200) have been developed the internal CRDM with the piston and cylinder of slightly different geometries. These systems are driven by the hydraulic force which is produced by pumps outside of the reactor vessel and transmitted through a pipe penetrating the reactor vessel, and needs complicated control and piping systems including pumps, valves and pipes etc.. IRIS has been recently decided the internal CRDMs as the reference design, and an analytical and experimental investigations of the hydraulic drive concept are performed by POLIMI in Italy. Also, a small French company, MP98 has been developed a new type of control rods, called 'liquid control rods', where reactivity is controlled by the movement of a liquid absorber in a manometer type device.

  6. Structure analysis of a reactor pressure vessel by two- and three-dimensional models. [PWR

    Energy Technology Data Exchange (ETDEWEB)

    Sacher, H.; Mayr, M.

    1982-03-01

    This paper investigates the reactor pressure vessel of a 1300 MW pressurised water reactor. In order to determine the stresses and deformations of the vessel, two- and three-dimensional finite element models are used which represent the real structure with different degrees of accuracy. The results achieved by these different models are compared for the case of the transient called ''Start up of the nuclear power plant''. 5 refs.

  7. Barometric pressure and gas composition

    Science.gov (United States)

    Malkin, V. B.

    1975-01-01

    Many factors affecting artificial gas atmosphere, which is used to maintain life during space flight, are considered. The wide variability of barometric pressure in spacecraft, due in large measure to spacecraft design is discussed. Explosive decompression is described; this develops from instantaneous depressurization of the cabin. Decompression sickness is reviewed, including bubble growth and evolution of gas bubbles in organisms. Dysbarism, hypoxia, and hypercapnia are also discussed.

  8. Time pressure test : fireworks compositions May 2008

    Energy Technology Data Exchange (ETDEWEB)

    Bowes, R.; Arsenault, D.

    2008-07-01

    This study was conducted to determine the feasibility of time-pressure tests on the pyrotechnic composition tables used to assign fireworks to dangerous goods divisions. The flash composition time was defined as the bursting charge or aural effect of the fireworks in relation to the amount of time taken for the pressure to rise. Seven fireworks samples were disassembled and tests were conducted in accordance with the UN manual for time-pressure tests in order to determine fireworks rise times and compare them to the results obtained from a sample of commercial sporting black powder. Results of the study indicated that the testing method is feasible. All 7 of the sample compositions were defined as flash compositions. The formulae of the fireworks were confirmed by chemical analysis. 1 tab.

  9. Application of high strength MnMoNi steel to pressure vessels for nuclear power plant

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, K.; Kurihara, I.; Sasaki, T.; Koyama, Y.; Tanaka, Y. [The Japan Steel Works, Ltd. (Japan)

    1999-07-01

    Recent increase in output of nuclear power plant has been attained by enlargement of major components such as pressure vessels. Such large components have almost reached limit of size from the points of manufacturing capacity and cost in both forgemasters and fabricaters. In order to solve this problem, it must be beneficial to apply design by use of material of higher strength which brings reduction of pressure vessel thickness and weight. The Japan Steel Works, Ltd. (JSW) has many manufacturing experiences of large integrated forgings made from high strength MnMoNi steel with tensile strength level of 620MPa for steam generator (SG) pressure vessel, and has made confirmation tests of its material properties. This paper describes the confirmation test results such as tensile and impact properties, nil-ductility transition temperature (NDT-T), static and dynamic fracture toughness weldability including under clad cracking (UCC) sensitivity and metallurgical factors which influence on such material properties. (orig.)

  10. Application of high strength MnMoNi steel to pressure vessels for nuclear power plant

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, K. E-mail: koumei_suzuki@jsw.co.jp; Kurihara, I.; Sasaki, T.; Koyoma, Y.; Tanaka, Y

    2001-06-01

    Recent increase in output of nuclear power plant has been attained by enlargement of major components such as pressure vessels. Such large components have almost reached a size limit from the points of manufacturing capacity and cost in both forgemasters and fabricaters. In order to solve this problem, it must be beneficial to apply design by use of material of higher strength, which brings reduction of pressure vessel thickness and weight. The Japan Steel Works Ltd. (JSW) has many manufacturing experiences of large integrated forgings made from high strength MnMoNi steel with tensile strength level of 620 MPa for steam generator (SG) pressure vessel, and has performed confirmation tests of its material properties. This paper describes the confirmation test results such as tensile and impact properties, nil-ductility transition temperature (NDT-T), static and dynamic fracture toughness, weldability including under-clad cracking (UCC) sensitivity, as well as metallurgical factors which influence on such material properties.

  11. Progress in understanding the mechanical behavior of pressure-vessel materials at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, R.W.; Brinkman, C.R.

    1981-01-01

    Progress during the 1970's on the production of high-temperature mechanical properties data for pressure vessel materials was reviewed. The direction of the research was toward satisfying new data requirements to implement advances in high-temperature inelastic design methods. To meet these needs, servo-controlled testing machines and high-resolution extensometry were developed to gain more information on the essential behavioral features of high-temperature alloys. The similarities and differences in the mechanical response of various pressure vessel materials were identified. High-temperature pressure vessel materials that have received the most attention included Type 304 stainless steel, Type 316 stainless steel, 2 1/4 Cr-1 Mo steel, alloy 800H, and Hastelloy X.

  12. Reactor pressure vessel head vents and methods of using the same

    Science.gov (United States)

    Gels, John L; Keck, David J; Deaver, Gerald A

    2014-10-28

    Internal head vents are usable in nuclear reactors and include piping inside of the reactor pressure vessel with a vent in the reactor upper head. Piping extends downward from the upper head and passes outside of the reactor to permit the gas to escape or be forcibly vented outside of the reactor without external piping on the upper head. The piping may include upper and lowers section that removably mate where the upper head joins to the reactor pressure vessel. The removable mating may include a compressible bellows and corresponding funnel. The piping is fabricated of nuclear-reactor-safe materials, including carbon steel, stainless steel, and/or a Ni--Cr--Fe alloy. Methods install an internal head vent in a nuclear reactor by securing piping to an internal surface of an upper head of the nuclear reactor and/or securing piping to an internal surface of a reactor pressure vessel.

  13. Transmural pressure during cardiogenic oscillations in rodent diaphragmatic lymphatic vessels.

    Science.gov (United States)

    Negrini, Daniela; Moriondo, Andrea; Mukenge, Sylvain

    2004-01-01

    The mechanism of initial lymphatic filling and the role of cardiogenic tissue motion in promoting lymph formation and propulsion are at present still controversial issues, in particular when considering interstitial tissues whose fluid pressure is well below atmospheric. To elucidate these aspects, the micropuncture technique was used to record interstitial (P(int)) and intralymphatic pressure (P(lymph)) simultaneously in the diaphragmatic lymphatic plexus draining the pleural cavity. The diaphragmatic lymphatic network was identified in anesthetized rabbits and rats through fluorescent dextrans injected intrapleurally. All P(lymph) and P(int) traces were pulsatile, oscillating either in-phase (33% of traces) or out-of-phase (67%) during cardiogenic swings. P(lymph) swept between -4.1 +/- 0.9 (SE) mmHg and 3.5 +/- 1.1 mmHg in rabbits, and between -5.1 +/- 1.0 mmHg and -2.7 +/- 1.1 mmHg in rats. P(int) oscillated between -0.8 +/- 0.7 mmHg and 4.9 +/- 0.7 mmHg in rabbits, and between -0.6 +/- 0.8 mmHg and 0.9 +/- 0.7 mmHg in rats. The data revealed a great functional complexity of the diaphragmatic lymphatic network and suggested that cardiogenic oscillations may play an important role in promoting lymph formation and propulsion from interstitial tissues with subatmospheric tissue pressure.

  14. Upper and Lower Bound Limit Loads for Thin-Walled Pressure Vessels Used for Aerosol Cans

    Directory of Open Access Journals (Sweden)

    Stephen John Hardy

    2009-01-01

    Full Text Available The elastic compensation method proposed by Mackenzie and Boyle is used to estimate the upper and lower bound limit (collapse loads for one-piece aluminium aerosol cans, which are thin-walled pressure vessels subjected to internal pressure loading. Elastic-plastic finite element predictions for yield and collapse pressures are found using axisymmetric models. However, it is shown that predictions for the elastic-plastic buckling of the vessel base require the use of a full three-dimensional model with a small unsymmetrical imperfection introduced. The finite element predictions for the internal pressure to cause complete failure via collapse fall within the upper and lower bounds. Hence the method, which involves only elastic analyses, can be used in place of complex elastic-plastic finite element analyses when upper and lower bound estimates are adequate for design purposes. Similarly, the lower bound value underpredicts the pressure at which first yield occurs.

  15. The deterministic structural integrity assessment of reactor pressure vessels under pressurized thermal shock loading

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Mingya, E-mail: chenmingya@cgnpc.com.cn; Lu, Feng; Wang, Rongshan; Huang, Ping; Liu, Xiangbin; Zhang, Guodong; Xu, Chaoliang

    2015-07-15

    Highlights: • The conservative and non-conservative assumptions in the codes were shown. • The influence of different loads on the SM was given. • The unloading effect of the cladding was studied. • A concentrated reflection of the safety was shown based on 3-D FE analyses. - Abstract: The deterministic structural integrity of a reactor pressure vessel (RPV) related to pressurized thermal shocks (PTSs) has been extensively studied. While the nil-ductility-transition temperature (RT{sub NDT}) parameter is widely used, the influence of fluence and temperature distributions along the thickness of the base metal wall cannot be reflected in the comparative analysis. This paper introduces the method using a structure safety margin (SM) parameter which is based on a comparison between the material toughness (the fracture initiation toughness K{sub IC} or fracture arrest toughness K{sub Ia}) and the stress intensity factor (SIF) along the crack front for the integrity analysis of a RPV subjected to PTS transients. A 3-D finite element model is used to perform fracture mechanics analyses considering both crack initiation assessment and arrest assessment. The results show that the critical part along the crack front is always the clad-base metal interface point (IP) rather than the deepest point (DP) for either crack initiation assessment or crack arrest assessment under the thermal load. It is shown that the requirement in Regulatory Guide 1.154 that ‘axial flaws with depths less than 20% of the wall thickness and all circumferential flaws should be modeled in infinite length’ may be non-conservative. As the assessment result is often poor universal for a given material, crack and transient, caution is recommended in the safety assessment, especially for the IP. The SIF reduces under the thermal or pressure load if the map cracking (MC) effect is considered. Therefore, the assumption in the ASME and RCCM codes that the cladding should be taken into account in

  16. Collaborative investigations of in-service irradiated material from the Japan Power Demonstration Reactor pressure vessel

    Energy Technology Data Exchange (ETDEWEB)

    Corwin, W.R.; Broadhead, B.L. [Oak Ridge National Lab., TN (United States); Suzuki, M.; Kohsaka, A. [Japan Atomic Energy Research Institute, Tokai (Japan)

    1997-02-01

    There is a need to validate the results of irradiation effects research by the examination of material taken directly from the wall of a pressure vessel that has been irradiated during normal service. Just such an evaluation is currently being conducted on material from the wall of the pressure vessel from the Japan Power Demonstration Reactor (JPDR). The research is being jointly performed at the Tokai Research Establishment of the Japan Atomic Energy Research Institute (JAERI) and by the Nuclear Regulatory Commission (NRC)-funded Heavy-Section Steel Irradiation Program at the Oak Ridge National Laboratory (ORNL).

  17. Pressure vessel made by free forming using underwater explosion

    Directory of Open Access Journals (Sweden)

    H Iyama

    2016-03-01

    Full Text Available Explosive forming is one particular forming technique, in which, mostcommonly, water is used as the pressure transmission medium. In recentyears, we have done the development of the method which obtains anecessary form of the metal by the control of underwater shock wave actson the metal plate, without a metal die. On the other hand, the pressurevessel is required in various fields, but we think that the free forming usingthe underwater shock wave is advantageous in the production of pressurevessel of a simple spherical, ellipse, parabola shape. In this paper, we willintroduce an experiment and several numerical simulations that we carriedout for this technical development.

  18. In-Vessel Melt Retention of Pressurized Water Reactors: Historical Review and Future Research Needs

    Directory of Open Access Journals (Sweden)

    Weimin Ma

    2016-03-01

    Full Text Available A historical review of in-vessel melt retention (IVR is given, which is a severe accident mitigation measure extensively applied in Generation III pressurized water reactors (PWRs. The idea of IVR actually originated from the back-fitting of the Generation II reactor Loviisa VVER-440 in order to cope with the core-melt risk. It was then employed in the new deigns such as Westinghouse AP1000, the Korean APR1400 as well as Chinese advanced PWR designs HPR1000 and CAP1400. The most influential phenomena on the IVR strategy are in-vessel core melt evolution, the heat fluxes imposed on the vessel by the molten core, and the external cooling of the reactor pressure vessel (RPV. For in-vessel melt evolution, past focus has only been placed on the melt pool convection in the lower plenum of the RPV; however, through our review and analysis, we believe that other in-vessel phenomena, including core degradation and relocation, debris formation, and coolability and melt pool formation, may all contribute to the final state of the melt pool and its thermal loads on the lower head. By looking into previous research on relevant topics, we aim to identify the missing pieces in the picture. Based on the state of the art, we conclude by proposing future research needs.

  19. Embrittlement and annealing of reactor pressure vessel steels: comparison of BR3 surveillance and vessel plates to the surrogate plates representative of the Yankee Rowe vessel

    Energy Technology Data Exchange (ETDEWEB)

    Fabry, A.; Chaouadi, T.; Puzzolante, J.L.; Van de Velde, J. [Centre de l``Etude de l``Energie Nucleaire, Mol (Belgium); Biemiller, E.C. [Yankee Atomic Electric Company, Bolton (United States); Rossinski, S.T.; Carter, R.G. [Electric Power Research Institute, Charlotte (United States)

    1996-07-01

    The sister pressure vessels at the BR3 and Rowe Yankee PWR plants were operated at a lower-than-usual temperature (260 degrees Celsius) and their plates were austenitized at higher-than-usual temperature (970 degrees Celsius). A heat tratemement leading to a coarser microstructure than typical for the fine grain plates that are considered in development of USNRC Regulatory guide 1.99. This material displayed outlier behaviour charackterized by a 41J CVN-shift significantly larger than predicted by Regulatory Guide 1.99. Because lower radiation temperature and nickell alloying are generally considered detrimental to irradiation sensitivity, there was a major concern that the nickel-modified lower Rowe plate and the nickel-modified BR3 plate may become too embrittled to satisfy the toughness requirements enbodied in the PTS screening criterion. This paper compares three complementary studies undertaken to clarify these uncertainties: 1) the accelerated irradiation and test program launched in 1990 by Yankee Atomic Electric Company using typical vessel plate materials containing 0.24% copper at two nickel levels: YA1, 0.63% (A533-B) and YA9, 0.19% (A302-B). These were heat-treated to produce the coarse and fine grain microstructures representative of the Yankee/BR3 and the Regulatory Guide plates, respectively, 2) the BR3 surveillance and vessel testing program: this vessel was wet-annealed in 1984, relicensed for operation till the plant shutdown in 1987, ANCL was trepanned in early 1995, 3) the accelerated irradiations in the Belgian BR2 test reactor of the Yankee coarse grain plates YA1 and YA9 together with BR3 vessel specimens extracted at nozzle elevation, a location with negligible radiation exposure. It is shown that the PTS screening criterion was never attained by the BR3 and Rowe plates, and that the BR3 vessel anneal was neither necessary nor sufficient. Finally, the sensitivity of embrittlement, annealing and post-annealing reembrittlement to irradiation

  20. The correlation between cognitive impairment and ambulatory blood pressure in patients with cerebral small vessel disease.

    Science.gov (United States)

    Li, X-F; Cui, L-M; Sun, D-K; Wang, H-T; Liu, W-G

    2017-07-01

    The present study was aimed to analyze the correlation between cognitive impairment and ambulatory blood pressure in patients with cerebral small vessel disease (CSVD). 108 patients with CSVD received in our hospital were selected. Assessment of cognitive impairment was by the Montreal Cognitive Assessment (MoCA). 39 cases were established as the impairment group and 69 cases were established as the normal group. 24 h ambulatory blood pressure was monitored, and changes in ambulatory blood pressure parameters between the two groups were compared. Also, the correlation between blood pressure parameters and MoCA score were analyzed. Comparisons of ambulatory systolic blood pressure, ambulatory pulse pressure and the ratios of night blood pressure reduction of patients in both groups showed statistical differences (p 0.05). The comparison of the blood pressure curves in both groups showed statistical differences (p ambulatory systolic blood pressure, ambulatory pulse pressure and the ratio of night blood pressure reduction of patients with CSVD showed prominently negative correlations with MoCA score (p ambulatory blood pressure of patients with CSVD are intimately correlated. The rise of ambulatory systolic blood pressure, pulse pressure, and the decline of blood pressure may represent risk factors for cognitive impairment in patients with CSVD. Improving blood pressure management will reduce the incidence of cognitive impairment caused by CSVD.

  1. The probabilistic structural integrity assessment of reactor pressure vessels under pressurized thermal shock loading

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Mingya, E-mail: chenmingya@cgnpc.com.cn [Suzhou Nuclear Power Research Institute, 215004 Suzhou, Jiangsu Province (China); Lu, Feng; Wang, Rongshan; Yu, Weiwei [Suzhou Nuclear Power Research Institute, 215004 Suzhou, Jiangsu Province (China); Wang, Donghui [State Nuclear Power Plant Service Company, 200237 Shanghai (China); Zhang, Guodong; Xue, Fei [Suzhou Nuclear Power Research Institute, 215004 Suzhou, Jiangsu Province (China)

    2015-12-01

    Highlights: • The methodology and the case study of the FAVOR software were shown. • The over-conservative parameters in the DFM were shown. • The differences between the PFM and the DFM were discussed. • The limits in the current FAVOR were studied. - Abstract: The pressurized thermal shock (PTS) event poses a potentially significant challenge to the structural integrity of the reactor pressure vessel (RPV) during the long time operation (LTO). In the USA, the “screening criteria” for maximum allowable embrittlement of RPV material, which forms part of the USA regulations, is based on the probabilistic fracture mechanics (PFM). The FAVOR software developed by Oak Ridge National Laboratory (ORNL) is used to establish the regulation. As the technical basis of FAVOR is not the most widely-used and codified methodologies, such as the ASME and RCC-M codes, in most countries (with exception of the USA), proving RPV integrity under the PTS load is still based on the deterministic fracture mechanics (DFM). As the maximum nil-ductility-transition temperature (RT{sub NDT}) of the beltline material for the 54 French RPVs after 40 years operation is higher than the critical values in the IAEA-TECDOC-1627 and European NEA/CSNI/R(99)3 reports (while still obviously lower than the “screening criteria” of the USA), it may conclude that the RPV will not be able to run in the LTO based on the DFM. In the FAVOR, the newest developments of fracture mechanics are applied, such as the warm pre-stress (WPS) effect, more accurate estimation of the flaw information and less conservation of the toughness (such as the three-parameter Weibull distribution of the fracture toughness). In this paper, the FAVOR software is first applied to show both the methodology and the results of the PFM, and then the limits in the current FAVOR software (Version 6.1, which represents the baseline for re-assessing the regulation of 10 CFR 50.61), lack of the impact of the constraint effect

  2. Joining dissimilar stainless steels for pressure vessel components

    Science.gov (United States)

    Sun, Zheng; Han, Huai-Yue

    1994-03-01

    A series of studies was carried out to examine the weldability and properties of dissimilar steel joints between martensitic and austenitic stainless steels - F6NM (OCr13Ni4Mo) and AISI 347, respectively. Such joints are important parts in, e.g. the primary circuit of a pressurized water reactor (PWR). This kind of joint requires both good mechanical properties, corrosion resistance and a stable magnetic permeability besides good weldability. The weldability tests included weld thermal simulation of the martensitic steel for investigating the influence of weld thermal cycles and post-weld heat treatment (PWHT) on the mechanical properties of the heat-affected zone (HAZ); implant testing for examining the tendency for cold cracking of martensitic steel; rigid restraint testing for determining hot crack susceptibility of the multi-pass dissimilar steel joints. The joints were subjected to various mechanical tests including a tensile test, bending test and impact test at various temperatures, as well as slow strain-rate test for examining the stress corrosion cracking tendency in the simulated environment of a primary circuit of a PWR. The results of various tests indicated that the quality of the tube/tube joints is satisfactory for meeting all the design requirements.

  3. Characterization of Nanostructural Features in Irradiated Reactor Pressure Vessel Model Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Wirth, B D; Odette, G R; Asoka-Kumar, P; Howell, R H; Sterne, P A

    2001-08-01

    Irradiation embrittlement in nuclear reactor pressure vessel steels results from the formation of a high number density of nanometer-sized copper rich precipitates and sub-nanometer defect-solute clusters. We present results of small angle neutron scattering (SANS) and positron annihilation spectroscopy (PAS) characterization of the nanostructural features formed in binary and ternary Fe-Cu-Mn alloys irradiated at {approx}290 C. These complementary techniques provide insight into the composition and character of both types of nanoscale features. The SANS measurements indicate populations of copper-manganese precipitates and smaller vacancy-copper-manganese clusters. The PAS characterization, including both Doppler broadening and positron lifetime measurements, indicates the presence of essentially defect-free Cu precipitates in the Fe-Cu-Mn alloy and vacancy-copper clusters in the Fe-Cu alloy. Thus the SANS and PAS provide a self-consistent picture of nanostructures composed of copper-rich precipitates and vacancy solute cluster complexes and tend to discount high Fe concentrations in the CRPs.

  4. 77 FR 16270 - Updated Aging Management Criteria for Reactor Vessel Internal Components of Pressurized Water...

    Science.gov (United States)

    2012-03-20

    ... COMMISSION Updated Aging Management Criteria for Reactor Vessel Internal Components of Pressurized Water... license renewal interim staff guidance (LR-ISG), LR-ISG-2011-04, ``Updated Aging Management Criteria for... Aging Lessons Learned (GALL) Report for the aging management of stainless steel structures and...

  5. An improved correlation of the pressure drop in stenotic vessels using Lorentz's reciprocal theorem

    Science.gov (United States)

    Ji, Chang-Jin; Sugiyama, Kazuyasu; Noda, Shigeho; He, Ying; Himeno, Ryutaro

    2015-02-01

    A mathematical model of the human cardiovascular system in conjunction with an accurate lumped model for a stenosis can provide better insights into the pressure wave propagation at pathological conditions. In this study, a theoretical relation between pressure drop and flow rate based on Lorentz's reciprocal theorem is derived, which offers an identity to describe the relevance of the geometry and the convective momentum transport to the drag force. A voxel-based simulator V-FLOW VOF3D, where the vessel geometry is expressed by using volume of fluid (VOF) functions, is employed to find the flow distribution in an idealized stenosis vessel and the identity was validated numerically. It is revealed from the correlation that the pressure drop of NS flow in a stenosis vessel can be decomposed into a linear term caused by Stokes flow with the same boundary conditions, and two nonlinear terms. Furthermore, the linear term for the pressure drop of Stokes flow can be summarized as a correlation by using a modified equation of lubrication theory, which gives favorable results compared to the numerical ones. The contribution of the nonlinear terms to the pressure drop was analyzed numerically, and it is found that geometric shape and momentum transport are the primary factors for the enhancement of drag force. This work paves a way to simulate the blood flow and pressure propagation under different stenosis conditions by using 1D mathematical model.

  6. Standard practice for examination of seamless, gas-filled, steel pressure vessels using angle beam ultrasonics

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 This practice describes a contact angle-beam shear wave ultrasonic technique to detect and locate the circumferential position of longitudinally oriented discontinuities and to compare the amplitude of the indication from such discontinuities to that of a specified reference notch. This practice does not address examination of the vessel ends. The basic principles of contact angle-beam examination can be found in Practice E 587. Application to pipe and tubing, including the use of notches for standardization, is described in Practice E 213. 1.2 This practice is appropriate for the ultrasonic examination of cylindrical sections of gas-filled, seamless, steel pressure vessels such as those used for the storage and transportation of pressurized gasses. It is applicable to both isolated vessels and those in assemblies. 1.3 The practice is intended to be used following an Acoustic Emission (AE) examination of stacked seamless gaseous pressure vessels (with limited surface scanning area) described in Test Met...

  7. Sensitivity coefficients for the stochastic estimation of the radiation damage to the reactor pressure vessel

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez, C.M.; Hernandez Valle, S. [Centro de Investigaciones Tecnologicas, Nucleares y Ambientales, La Habana (Cuba). E-mail: calvarez@ctn.isctn.edu.cu; svalle@ctn.isctn.edu.cu

    2000-07-01

    The construction of the sensitivity matrix in the case of the vessel radiation damage estimation by Monte Carlo techniques poses new problems related to the uncertainties of the obtained responses. In the case of deterministic calculations, the sensitivity coefficient obtention is a straightforward procedure based on the perturbation formalism through the calculation of the adjoint fluxes. In the paper an alternative procedure implementation based on the differential operator method is described with the modifications needed to the used HEXANN-EVALU code for the response estimations in the VVER-440 pressure vessel. (author)

  8. Fracture assessment of the Oskarshamn 1 reactor pressure vessel under cold over-pressurization

    Energy Technology Data Exchange (ETDEWEB)

    Sattari-Far, I. [DNV Technical Consulting AB, Stockholm (Sweden)

    2001-03-01

    The major motivation of this study was to develop a methodology for fracture assessment of surface defects in the 01 reactor pressure vessel under cold loading scenarios, particularly the cold over-pressurization event. According to a previous study, the FENIX project, the cold over-pressurization of the O1 reactor is a limiting loading case, as the ductile/brittle transition temperature (RT{sub NDT}) of certain welds in the O1 beltline region may be over 100 deg C at the-end-of-life condition. The FENIX project gave values of the acceptable and critical crack depth to be equal to the thickness of the cladding layer (about 6 mm) under this load case using the ASME K{sub Ic} reference curve methodology. This study is aimed to develop a methodology to give a more precise fracture assessment of the O1 reactor under cold loading scenarios. Some of the main objectives of this study have been as below: To prepare a material which can simulate the mechanical properties and RT{sub NDT} of the O1 reactor at the end-of-life conditions. To conduct a fracture mechanics test program to cover the essential influencing factors, such as crack geometry (shallow and deep cracks) and loading condition (uniaxial and biaxial) on the cleavage fracture toughness. To perform fracture mechanics analyses to identify a suitable methodology for assessment of the experimental results. To study the responses of engineering fracture assessment methods to the experimental results from the clad specimens. To propose a fracture assessment procedure for determination of the acceptable and critical flaw sizes in the 01 reactor under the cold loading events. A test program consisted of experiments on standard SEN(B) specimens and clad beams, containing surface cracks was conducted during the course of this project. A total of nine clad beams and clad cruciform specimens were tested under uniaxial and biaxial loading. The test material is reactor steel of type A 508 Grade B, which is specially heat

  9. New ASTM Standards for Nondestructive Testing of Aerospace Composites

    Science.gov (United States)

    Waller, Jess M.; Saulsberry, Regor L.

    2010-01-01

    Problem: Lack of consensus standards containing procedural detail for NDE of polymer matrix composite materials: I. Flat panel composites. II. Composite components with more complex geometries a) Pressure vessels: 1) composite overwrapped pressure vessels (COPVs). 2) composite pressure vessels (CPVs). III. Sandwich core constructions. Metal and brittle matrix composites are a possible subject of future effort.

  10. Structure analysis of a reactor pressure vessel by two and three-dimensional models

    Energy Technology Data Exchange (ETDEWEB)

    Sacher, H.; Mayr, M. (Technischer Ueberwachungs-Verein Bayern e.V., Muenchen (Germany, F.R.))

    1982-03-01

    This paper investigates the reactor pressure vessel of a 1300 MW pressurised water reactor. In order to determine the stresses and deformations of the vessel, two- and three-dimensional finite element models are used which represent the real structure with different degrees of accuracy. The results achieved by these different models are compared for the case of the transient called 'Start up of the nuclear power plant'. It was found that axisymmetric models, which consider non-axisymmetric components by correction factors, together with special attention to holes and other stress concentrations, allow a sufficient computation of stresses and deformations in the vessel, with the exception of the coolant nozzle region. In this latter case a fully three-dimensional analysis may be necessary.

  11. Finite element analysis to estimate burst pressure of mild steel pressure vessel using Ramberg–Osgood model

    Directory of Open Access Journals (Sweden)

    Puneet Deolia

    2016-09-01

    Full Text Available Burst pressure is the pressure at which vessel burst/crack and internal fluid leaks. An accurate prediction of burst pressure is necessary in chemical, medical and aviation industry. Burst pressure is a design safety limit, which should not be exceeded. If this pressure is exceeded it may lead to the mechanical breach and permanent loss of pressure containment. So burst pressure calculation is necessary for all the critical applications. To numerically calculate burst pressure material curve is essential. There are various material models which are used to define material curve, amongst them Ramberg–Osgood is very popular. Ramberg–Osgood accurately capture material curve in strain hardening region. This approach is applicable for different material grades. In this paper a finite element method is used to predict burst pressure using Ramberg–Osgood equation. These results are then compared with results obtained from elasto-plastic curve and true stress strain curve. Results obtained by finite element analysis are validated with experimental data which is considered from open literature.

  12. In-vessel core debris retention through external flooding of the reactor pressure vessel. State-of-the-art report

    Energy Technology Data Exchange (ETDEWEB)

    Heel, A.M.J.M. van

    1995-07-01

    An overview of the state-of-the-art knowledge on the ex-vessel flooding accident management strategy for severe accidents in a NPP has been given. The feasibility has been discussed, as well as the in- and ex-vessel phenomena, which influence the structural integrity of the vessel. Finally, some computer codes with the ability to model the phenomena involved in ex-vessel flooding have been discussed. (orig./HP).

  13. Research on inner defect detection of pressure vessels with digital shearography

    Science.gov (United States)

    Feng, X.; He, X. Y.; Tian, Ch. P.; Zhou, H. H.

    2015-03-01

    The digital shearograghy method has shown strong cutting edge in the whole-field measurement, the simple optical road, the easy modulation and the low demand for environment. Also the phase-shifting method which is used in digital shearograghy can improve the precision of the measurement greatly. And therefore these methods are used in Non Destructive Testing (NDT) widely. In this paper, the inner defect detection of pressure vessels was studied via the theoretical mode, the numerical simulation (finite element method) and the experiment in which the digital shearograhy and phase-shifting method was used. The first-order derivative maximum of the out-of-plane displacement in the defect which have different diameters and depths under the various pressures were obtained and compared with each other. And the results obtained with the three different means mentioned above are consistent. According to the maximum number of 1st derivation, the defect of pressure vessels is detected when the proportion of the diameter and the thickness of defect is the more than 9. In addition, the phase diagrams and the out-of-plane displacement gradients were also gained. Based on the phase diagram, it is easily determined whether the defect exists, and the defect relative size can be qualitatively obtained. It is proved that there is feasibility and advantage of the digital shearograghy when it is used in inner defect detection of pressure vessels. This study can provide a new method that is able to detect inner defects of pressure vessels and widen the application of the digital shearograghy.

  14. Composite Overwrapped Pressure Vessels (COPV) Monitoring System Using Fiber Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Intelligent Fiber Optic Systems Corporation (IFOS) proposes, in this Phase 1 SBIR project, to demonstrate the feasibility of innovations based on an...

  15. Development of Mono-bloc Forging for CAP1400 Reactor Pressure Vessel

    Science.gov (United States)

    Bao-zhong, Wang; Kai-quan, Liu; Ying, Liu; Wen-hui, Zhang; De-li, Zhao

    With the Development of Larger Output and Longer Plant Life for Advanced Pressurized Water Reactor Pressure Vessel (APWRPV), Larger and Mono-bloc Forgings must be Necessary. In the researching and manufacturing of CAP1400RPV forgings, China First Heavy Industries (CFHI) Manufactured Mono-bloc Upper Head with Quick-loc and Mono-bloc Lower Head (Combined Part of Transition Ring and Lower Head),reducing the welding process and the mechanical property deference comparing with the traditional manufacturing, Comparing with AP1000 forgings, not only Obtained better Mechanical Properties, but also Reduced Manufacturing cycle of RPV and Nondestructive in-service Inspection due to Elimination of Weld Seams. CHFI will Development Mono-bloc Nozzle Shell (Combined Part of Vessel Flange Nozzle Shell and Inlet/Outlet Nozzles) for Future APWRPV.

  16. IAEA international studies on irradiation embrittlement of reactor pressure vessel steels

    Energy Technology Data Exchange (ETDEWEB)

    Brumovsky, M. [Nuclear Research Institute Rez plc (Czech Republic); Steele, L.E. [Chief Scientific Investigator of the Programme, Springfield, VA (United States)

    1997-02-01

    In last 25 years, three phases a Co-operative Research Programme on Irradiation Embrittlement of Reactor Pressure Vessel Steels has been organized by the International Atomic Energy Agency. This programme started with eight countries in 1971 and finally 16 countries took part in phase III of the Programme in 1983. Several main efforts were put into preparation of the programme, but the principal task was concentrated on an international comparison of radiation damage characterization by different laboratories for steels of {open_quotes}old{close_quotes} (with high impurity contents) and {open_quotes}advanced{close_quotes} (with low impurity contents) types as well as on development of small scale fracture mechanics procedures applicable to reactor pressure vessel surveillance programmes. This year, a new programme has been opened, concentrated mostly on small scale fracture mechanics testing.

  17. A study on quantitative measurement of internal defects of pressure vessel by digital shearography

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung Tae; Kang, Young Jun; Jang, Jong Min [Chonbuk National University, Chonju (Korea, Republic of)

    1999-11-15

    Pipelines in power plants, nuclear facilities and chemical industries are often affected by corrosion effects. It is very important in detect such internal flaws of pipelines because they sometimes bring about serious problems. Conventional NDT methods have been taken relatively much time, money, and manpower because of performing as the method of contact with objects to be inspected. Digital shearography is a laser-based optical method which allows full-field observation of surface displacement derivatives. This method has many advantages in practical use, such as low sensitivity to environmental noise, simple optical configuration and real time measurement. In this paper, the experiment was performed with some pressure vessels which has different internal cracks. We measured internal crack length of the pressure vessels at a real time and compared with FEM simulation results.

  18. A study on detection of internal defects of pressure vessel by digital shearography

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Young Jun; Park, Sung Tae [Chonbuk National University, Chonju (Korea, Republic of); Lee, Hae Moo; Nam, Seung Hun [Failure Prevention Research Center KRISS, Daejeon (Korea, Republic of)

    1999-05-15

    Pipelines in power plants, nuclear facilities and chemical industries are often affected by corrosion effects. The inspection of internal defects of these pipelines is important to guarantee safe operational condition. Conventional NDT methods have been taken relatively much time, money, and manpower because of performing as the method of contact with objects to be inspected. Digital shearography is a laser-based optical method which allows full-field observation of surface displacement derivatives. This method has many advantages in practical use, such as low sensitivity to environmental noise, simple optical configuration and real time measurement. Therefore it is a good method to use for detecting internal defects. In this paper, the experiment was performed with some pressure vessels which has different internal cracks. We detected internal cracks of the pressure vessels at a real time and evaluated qualitatively these results. We also performed qualitative measurement of shearo fringe by using phase shifting method.

  19. A Study on Measurement of Internal Defects of Pressure Vessel by Digital Shearography(I)

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Young June; Park, Nak Kyu; Ryu, Won Jae [Chonbuk National University, Jeonju (Korea, Republic of); Kim, Kyung Suk [Chosun University, Gwangju (Korea, Republic of)

    2002-08-15

    Pipelines in power plants, nuclear facilities and chemical industries are often affected by corrosion effects. It is important to inspect the internal defects in pipelines in order to guarantee safe operational condition. We have taken relatively much time, cost and manpower to use conventional NDT methods because these methods are contact measuring methods. In this paper, we used digital shearography, a laser-based optical method which allows full-field measurement of surface displacement derivatives. This method has many advantages in practical use, such as low sensitivity to environmental noise, simple optical configuration and real time measurement. The experiment was performed with pressure vessels which has different internal cracks and detected internal cracks in the pressure vessels at a real time using phase shifting method

  20. Effect of Silicon Content on Carbide Precipitation and Low-Temperature Toughness of Pressure Vessel Steels

    Science.gov (United States)

    Ruan, L. H.; Wu, K. M.; Qiu, J. A.; Shirzadi, A. A.; Rodionova, I. G.

    2017-05-01

    Cr - Mn - Mo - Ni pressure vessel steels containing 0.54 and 1.55% Si are studied. Metallographic and fractographic analyses of the steels after tempering at 650 and 700°C are performed. The impact toughness at - 30°C and the hardness of the steels are determined. The mass fraction of the carbide phase in the steels is computed with the help of the J-MatPro 4.0 software.

  1. Nuclear power station with a water-cooled reactor pressure vessel. Kernkraftwerk mit einem wassergekuehlten Reaktordruckbehaelter

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, R.; Brunner, G.; Jost, N.

    1987-10-29

    Nuclear radiation produces radiolysis gases, which are undesirable for corrosion and oxyhydrogen gas reasons. To limit the proportion of this radiolysis gas, the invention provides that catalytic surfaces should be introduced into the primary circuit, to produce recombination of hydrogen and oxygen. These surfaces can be accommodated in the upper part of the reactor pressure vessel. The live steam screen can also have a catalytic surface.

  2. Implementation of 3D-Imaging technique for visual testing in a nuclear reactor pressure vessel

    OpenAIRE

    Tanco, André

    2014-01-01

    This master thesis has been performed by request of Dekra Industrial AB. Dekra Industrial AB is a Swedish subsidiary company of the German company Dekra and works for example with safety inspections within the nuclear power industry. The inspections performed by the company are often non-destructive testing (NDT) such as visual inspections of nuclear reactor pressure vessels. The inspection methods used today are considered to be further developed and there is a strong demand of improving the...

  3. FRACTURE MECHANICS UNCERTAINTY ANALYSIS IN THE RELIABILITY ASSESSMENT OF THE REACTOR PRESSURE VESSEL: (2D SUBJECTED TO INTERNAL PRESSURE

    Directory of Open Access Journals (Sweden)

    Entin Hartini

    2016-06-01

    Full Text Available ABSTRACT FRACTURE MECHANICS UNCERTAINTY ANALYSIS IN THE RELIABILITY ASSESSMENT OF THE REACTOR PRESSURE VESSEL: (2D SUBJECTED TO INTERNAL PRESSURE. The reactor pressure vessel (RPV is a pressure boundary in the PWR type reactor which serves to confine radioactive material during chain reaction process. The integrity of the RPV must be guaranteed either  in a normal operation or accident conditions. In analyzing the integrity of RPV, especially related to the crack behavior which can introduce break to the reactor pressure vessel, a fracture mechanic approach should be taken for this assessment. The uncertainty of input used in the assessment, such as mechanical properties and physical environment, becomes a reason that the assessment is not sufficient if it is perfomed only by deterministic approach. Therefore, the uncertainty approach should be applied. The aim of this study is to analize the uncertainty of fracture mechanics calculations in evaluating the reliability of PWR`s reactor pressure vessel. Random character of input quantity was generated using probabilistic principles and theories. Fracture mechanics analysis is solved by Finite Element Method (FEM with  MSC MARC software, while uncertainty input analysis is done based on probability density function with Latin Hypercube Sampling (LHS using python script. The output of MSC MARC is a J-integral value, which is converted into stress intensity factor for evaluating the reliability of RPV’s 2D. From the result of the calculation, it can be concluded that the SIF from  probabilistic method, reached the limit value of  fracture toughness earlier than SIF from  deterministic method.  The SIF generated by the probabilistic method is 105.240 MPa m0.5. Meanwhile, the SIF generated by deterministic method is 100.876 MPa m0.5. Keywords: Uncertainty analysis, fracture mechanics, LHS, FEM, reactor pressure vessels   ABSTRAK ANALISIS KETIDAKPASTIAN FRACTURE MECHANIC PADA EVALUASI KEANDALAN

  4. Cutting and conditioning of the reactor pressure vessel in the NPP Wuergassen; Zerlegung und Konditionierung des Reaktordruckgefaesses im Kernkraftwerk Wuergassen

    Energy Technology Data Exchange (ETDEWEB)

    Kraps, Uwe [AREVA NP GmbH, Erlangen (Germany); Duwe, Peter [E.ON Kernkraft GmbH, Bewerungen (Germany)

    2011-07-01

    NPP Wuergassen was shutdown in 1995 after 23 years of operation. Since 1997 the nuclear power plant is being dismantled. The cutting of the reactor pressure vessel internals was performed between 2003 and 2008. After decontamination the cylindrical parts of the reactor pressure vessel were dissected, the process was finalized in 2010. AREVA has now a 30 years-experience concerning repair, replacement and dismantling of reactor components. In the contribution the authors describe the process planning, manufacture and testing of appropriate remote handled tools, decontamination, dissection of the pressure vessel (320 t), conditioning, packaging and transport of the radioactive waste including radiation protection monitoring.

  5. 46 CFR 54.01-2 - Adoption of division 1 of section VIII of the ASME Boiler and Pressure Vessel Code.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Adoption of division 1 of section VIII of the ASME... division 1 of section VIII of the ASME Boiler and Pressure Vessel Code. (a) Pressure vessels shall be designed, constructed, and inspected in accordance with section VIII of the ASME Boiler and Pressure Vessel...

  6. Design and Analysis of Boiler Pressure Vessels based on IBR codes

    Science.gov (United States)

    Balakrishnan, B.; Kanimozhi, B.

    2017-05-01

    Pressure vessels components are widely used in the thermal and nuclear power plants for generating steam using the philosophy of heat transfer. In Thermal power plant, Coal is burnt inside the boiler furnace for generating the heat. The amount of heat produced through the combustion of pulverized coal is used in changing the phase transfer (i.e. Water into Super-Heated Steam) in the Pressure Parts Component. Pressure vessels are designed as per the Standards and Codes of the country, where the boiler is to be installed. One of the Standards followed in designing Pressure Parts is ASME (American Society of Mechanical Engineers). The mandatory requirements of ASME code must be satisfied by the manufacturer. In our project case, A Shell/pipe which has been manufactured using ASME code has an issue during the drilling of hole. The Actual Size of the drilled holes must be, as per the drawing, but due to error, the size has been differentiate from approved design calculation (i.e. the diameter size has been exceeded). In order to rectify this error, we have included an additional reinforcement pad to the drilled and modified the design of header in accordance with the code requirements.

  7. A continuum damage analysis of hydrogen attack in a 2.25Cr-1Mo pressure vessel

    Energy Technology Data Exchange (ETDEWEB)

    Burg, M.W.D. van der; Giessen, E. van der [Technische Univ. Delft (Netherlands). Dept. of Mechanical Engineering; Tvergaard, V. [Danmarks Tekniske Hoejskole, Lyngby (Denmark). Dept. of Solid Mechanics

    1998-01-30

    A micromechanically based continuum damage model is presented to analyze the stress, temperature and hydrogen pressure dependent material degradation process termed hydrogen attack, inside a pressure vessel. Hydrogen attack (HA) is the damage process of grain boundary facets due to a chemical reaction of carbides with hydrogen, thus forming cavities with high pressure methane gas. Driven by the methane gas pressure, the cavities grow, while remote tensile stresses can significantly enhance the cavitation rate. The damage model gives the strain-rate and damage rate as a function of the temperature, hydrogen pressure and applied stresses. The model is applied to study HA in a vessel wall, where nonuniform distributions lf hydrogen pressure, temperature and stresses result in a nonuniform damage distribution over the vessel wall. Stresses inside the vessel wall first tend to accelerate and later decelerate the cavitation rate significantly. Numerical studies for different material parameters and different stress conditions demonstrate the HA process inside a vessel in time. Also, the lifetime of the pressure vessel is determined. The analyses underline that the general applicability of the Nelson curve is questionable. (orig.) 30 refs.

  8. Study on the welding continuous cooling transformation and weldability of SA508Gr4 steel for nuclear pressure vessels

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Qingwei; Ma, Yonglin; Xing, Shuqing; Chen, Zhongyi [Inner Mongolia Univ. of Science and Technology, Baotou (China). School of Material and Metallurgy; Kang, Xiaolan [Baotou Vocational and Technical College (China)

    2017-02-15

    SA508Gr4 is a newly developed high-strength steel for nuclear reactor pressure vessels. Its welding characteristics remain largely unexplored. In this work, the simulated heat affected zone continuous cooling transformation (SH-CCT) diagram of SA508Gr4 steel was constructed and the high-temperature cooling phase compositions and the properties of the heat affected zone (HAZ) were characterized using dilatometry and microscopic tests. The results show that the phase transformation in the HAZ was divided into bainite and martensite transformation stages. When 4.6 ≤ t{sub 8/5} (the HAZ cooling time from 800 C to 500 C) ≤ 15 s, lath-shaped martensite was fully developed, resulting in extensive hardening and cold cracking in the HAZ, while the cooling time required to form the bainite completely exceeds 1 200 s. Thus, to improve weld quality, preheating to 196 C or higher is recommended.

  9. Prestressed-concrete pressure vessels and their applicability to advanced-energy-system concepts

    Energy Technology Data Exchange (ETDEWEB)

    Naus, D.J

    1983-01-01

    Prestressed concrete pressure vessels (PCPVs) are, in essence, spaced steel structures since their strength is derived from a multitude of steel elements made up of deformed reinforcing bars and prestressing tendons which are present in sufficient quantities to carry tension loads imposed on the vessel. Other major components of a PCPV include the concrete, liner and cooling system, and insulation. PCPVs exhibit a number of advantages which make them ideally suited for application to advanced energy concepts: fabricability in virtually any size and shape using available technology, improved safety, reduced capital costs, and a history of proven performance. PCPVs have many applications to both nuclear- and non-nuclear-based energy systems concepts. Several of these concepts will be discussed as well as the research and development activities conducted at ORNL in support of PCPV development.

  10. Weld Repair of a Stamped Pressure Vessel in a Radiologically Controlled Zone

    Energy Technology Data Exchange (ETDEWEB)

    Cannell, Gary L. [Fluor Enterprises, Inc.; Huth, Ralph J. [CH2MHill Plateau Remediation Company; Hallum, Randall T. [Fluor Government Group

    2013-08-26

    In September 2012 an ASME B&PVC Section VIII stamped pressure vessel located at the DOE Hanford Site Effluent Treatment Facility (ETF) developed a through-wall leak. The vessel, a steam/brine heat exchanger, operated in a radiologically controlled zone (by the CH2MHill PRC or CHPRC), had been in service for approximately 17 years. The heat exchanger is part of a single train evaporator process and its failure caused the entire system to be shut down, significantly impacting facility operations. This paper describes the activities associated with failure characterization, technical decision making/planning for repair by welding, logistical challenges associated with performing work in a radiologically controlled zone, performing the repair, and administrative considerations related to ASME code requirements.

  11. RADIATION DOSIMETRY OF THE PRESSURE VESSEL INTERNALS OF THE HIGH FLUX BEAM REACTOR.

    Energy Technology Data Exchange (ETDEWEB)

    HOLDEN,N.E.; RECINIELLO,R.N.; HU,J.P.; RORER,D.C.

    2002-08-18

    In preparation for the eventual decommissioning of the High Flux Beam Reactor after the permanent removal of its fuel elements from the Brookhaven National Laboratory, both measurements and calculations of the decay gamma-ray dose rate have been performed for the reactor pressure vessel and vessel internal structures which included the upper and lower thermal shields, the transition plate, and the control rod blades. The measurements were made using Red Perspex{trademark} polymethyl methacrylate high-level film dosimeters, a Radcal ''peanut'' ion chamber, and Eberline's high-range ion chamber. To compare with measured gamma-ray dose rate, the Monte Carlo MCNP code and geometric progressive Microshield code were used to model the gamma transport and dose buildup.

  12. Creep crack growth in a reactor pressure vessel steel at 360 deg C

    Energy Technology Data Exchange (ETDEWEB)

    Rui Wu; Seitisleam, F.; Sandstroem, R. [Swedish Institute for Metals Research, Stockholm (Sweden)

    1998-12-31

    Plain creep (PC) and creep crack growth (CCG) tests at 360 deg C and post metallography were carried out on a low alloy reactor pressure vessel steel (ASTM A508 class 2) with different microstructures. Lives for the CCG tests were shorter than those for the PC tests and this is more pronounced for simulated heat affected zone microstructure than for the parent metal at longer lives. For the CCG tests, after initiation, the cracks grew constantly and intergranularly before they accelerated to approach rupture. The creep crack growth rate is well described by C*. The relations between reference stress, failure time and steady crack growth rate are presented for the CCG tests. It is demonstrated that the failure stress due to CCG is considerably lower than the yield stress at 360 deg C. Consequently, the CCG will control the static strength of a reactor vessel. (orig.) 17 refs.

  13. Test of 6-in. -thick pressure vessels. Series 4: intermediate test vessels V-5 and V-9 with inside nozzle corner cracks. [BWR and PWR

    Energy Technology Data Exchange (ETDEWEB)

    Merkle, J.G.; Robinson, G.C.; Holz, P.P.; Smith, J.E.

    1977-08-01

    Failure testing is described for two 99-cm-diam (39-in.), 15.2-cm-thick (6-in.) steel pressure vessels, each containing one flawed nozzle. Vessel V-5 was tested at 88/sup 0/C (190/sup 0/F) and failed by leaking without fracturing after extensive stable crack growth. Vessel V-9 was tested at 25/sup 0/C (75/sup 0/F) and failed by fracturing. Material properties measured before the tests were used for pretest and posttest fracture analyses. Test results supported by analysis indicate that inside nozzle corner cracks are not subject to plane strain under pressure loading. The preparation of inside nozzle corner cracks is described in detail. Extensive experimental data are tabulated and plotted.

  14. Swedish Work on Brittle-Fracture Problems in Nuclear Reactor Pressure Vessels

    Energy Technology Data Exchange (ETDEWEB)

    Grounes, M.

    1966-03-15

    After a short review of the part of the Swedish nuclear energy program that is of interest in this context the Swedish reactor pressure vessels and the reasoning behind the choice of materials are surveyed. Problems and desirable aims for future reactors are discussed. Much work is now being done on new types of pressure vessel steels with high strength, low transition temperature and good corrosion resistance. These steels are of the martensitic austenitic type Bofors 2RMO (13 % Cr, 6 % Ni, 1. 5 % Mo) and of the ferritic martensitic austenitic type Avesta 248 SV (16 % Cr, 5 % Ni, 1 % Mo). An applied philosophy for estimating the brittle-fracture tendency of pressure vessels is described. As a criterion of this tendency we use the crack-propagation transition temperature, e. g. as measured by the Robertson isothermal crack-arrest test. An estimate of this transition temperature at the end of the reactor' s lifetime must take increases due to fabrication, welding, geometry, ageing and irradiation into account. The transition temperature vs. stress curve moves towards higher temperatures during the reactor' s lifetime. As long as this curve does not cross the reactor vessel stress vs. temperature curve the vessel is considered safe. The magnitude of the different factors influencing the final transition temperature are discussed and data for the Marviken reactor's pressure vessel are presented. At the end of the reactor's lifetime the estimated transition temperature is 115 deg C, which is below the maximum permissible value. A program for the study of strain ageing has been initiated owing to the uncertainty as to the extent of strain ageing at low strains. A study of a simple crack-arrest test, developed in Sweden, is in progress. An extensive irradiation-effects program on several steels is in progress. Results from tests on the Swedish carbon-manganese steels 2103/R3, SIS 142103 and SIS 142102, the low-alloy steels Degerfors DE-631A, Bofors NO

  15. Standard practice for examination of seamless, Gas-Filled, pressure vessels using acoustic emission

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This practice provides guidelines for acoustic emission (AE) examinations of seamless pressure vessels (tubes) of the type used for distribution or storage of industrial gases. 1.2 This practice requires pressurization to a level greater than normal use. Pressurization medium may be gas or liquid. 1.3 This practice does not apply to vessels in cryogenic service. 1.4 The AE measurements are used to detect and locate emission sources. Other nondestructive test (NDT) methods must be used to evaluate the significance of AE sources. Procedures for other NDT techniques are beyond the scope of this practice. See Note 1. Note 1—Shear wave, angle beam ultrasonic examination is commonly used to establish circumferential position and dimensions of flaws that produce AE. Time of Flight Diffraction (TOFD), ultrasonic examination is also commonly used for flaw sizing. 1.5 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only. 1.6 This standa...

  16. Alternative welding reconditioning solutions without post welding heat treatment of pressure vessel

    Science.gov (United States)

    Cicic, D. T.; Rontescu, C.; Bogatu, A. M.; Dijmărescu, M. C.

    2017-08-01

    In pressure vessels, working on high temperature and high pressure may appear some defects, cracks for example, which may lead to failure in operation. When these nonconformities are identified, after certain examination, testing and result interpretation, the decision taken is to repair or to replace the deteriorate component. In the current legislation it’s stipulated that any repair, alteration or modification to an item of pressurised equipment that was originally post-weld heat treated after welding (PWHT) should be post-weld heat treated again after repair, requirement that cannot always be respected. For that reason, worldwide, there were developed various welding repair techniques without PWHT, among we find the Half Bead Technique (HBT) and Controlled Deposition Technique (CDT). The paper presents the experimental results obtained by applying the welding reconditioning techniques HBT and CDT in order to restore as quickly as possible the pressure vessels made of 13CrMo4-5. The effects of these techniques upon the heat affected zone are analysed, the graphics of the hardness variation are drawn and the resulted structures are compared in the two cases.

  17. A Study on Measurement of Internal Defects of Pressure Vessel by Digital Shearography(II)

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Young June; Park, Nak Kyu; Ryu, Won Jae; Kim, Dong Woo [Chonbuk National University, Jeonju (Korea, Republic of)

    2002-08-15

    Recently the necessity of study on optical measuring method using laser to detect the pipeline's defect in nuclear facilities, chemical industries and power plants has been increased. Because laser light can be delivered to a remote area without any difficulties, the application of laser in many industries can solve several difficulties from the limitation of access in danger area and reduce the risks of workers. Therefore, we applied a new experimental technique to the measurement of internal defects in pressure vessels with the combination of shearography and image processing technique and detected the internal cracks of pressure vessels in the former paper. In this paper, we used the same optical system as in the former study and found the optimum shearing magnitude by comparing the real length of specimen with experimental results. A variety of conditions were applied to certify the validity of this method. Actually, several specimens which have different lengths and depths were used in this experiment under the three diverse pressure. Consequently, we have carried out this experiment to determine the limit of measurement ability with analyzing errors

  18. The criteria of fracture in the case of the leak of pressure vessels

    Energy Technology Data Exchange (ETDEWEB)

    Habil; Ziliukas, A.

    1997-04-01

    In order to forecast the break of the high pressure vessels and the network of pipes in a nuclear reactor, according to the concept of leak before break of pressure vessels, it is necessary to analyze the conditions of project, production, and mounting quality as well as of exploitation. It is also necessary to evaluate the process of break by the help of the fracture criteria. In the Ignalina Nuclear Power Plant of, in Lithuania, the most important objects of investigation are: the highest pressure pipes, made of Japanese steel 19MN5 and having an anticorrosive austenitic: coal inside, the pipes of distribution, which arc made of 08X1810T steel. The steel of the network of pipes has a quality of plasticity: therefore the only criteria of fragile is impossible to apply to. The process of break would be best described by the universal criteria of elastic - plastic fracture. For this purpose the author offers the criterion of the double parameter.

  19. Fundamental study of failure mechanisms of pressure vessels under thermo-mechanical cycling in multiphase environments

    Science.gov (United States)

    Penso Mula, Jorge Antonio

    Cracking and bulging in welded and internally lined pressure vessels that work in thermal-mechanical cycling services have been well known problems in the petrochemical, power and nuclear industries. Published literature and industry surveys show that similar problems have been occurring during the last 50 years. Understanding the causes of cracking and bulging would lead to improvements in the reliability of these pressure vessels. This study attempts to add information required for improving the knowledge and fundamental understanding of these problems. Cracking and bulging, most often in the weld areas, commonly experienced in delayed coking units (e.g. coke drums) in oil refineries are typical examples. The coke drum was selected for this study because of the existing field experience and past industrial investigation results that were available to serve as the baseline references for the analytical studies performed for this dissertation. Another reason for selecting the delayed coking units for this study was due to their high economical yields. Shutting down these units would cause a high negative economic impact on the refinery operations. Several failure mechanisms were hypothesized. The finite element method was used to analyze these significant variables and to verify the hypotheses. In conclusion, a fundamental explanation of the occurrence of bulging and cracking in pressure vessels in multiphase environments has been developed. Several important factors have been identified, including the high convection coefficient of the boiling layer during filling and quenching, the mismatch in physical, thermal and mechanical properties in the dissimilar weld of the clad plates and process conditions such as heating and quenching rate and warming time. Material selection for coke drums should consider not only fatigue strength but also corrosion resistance at high temperatures and low temperatures. Cracking occurs due to low cycle fatigue and corrosion. The FEA

  20. In-Vessel Melt Retention of Pressurized Water Reactors: Historical Review and Future Research Needs

    OpenAIRE

    Ma, Weimin; Yuan, Yidan; Sehgal, Bal Raj

    2016-01-01

    A historical review of in-vessel melt retention (IVR) is given, which is a severe accident mitigation measure extensively applied in Generation III pressurized water reactors (PWRs). The idea of IVR actually originated from the back-fitting of the Generation II reactor Loviisa VVER-440 in order to cope with the core-melt risk. It was then employed in the new deigns such as Westinghouse AP1000, the Korean APR1400 as well as Chinese advanced PWR designs HPR1000 and CAP1400. The most influential...

  1. Improvement of remote control system of automatic ultrasonic equipment for inspection of reactor pressure vessel

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, Yong Moo; Jung, H. K.; Joo, Y. S.; Koo, K. M.; Hyung, H.; Sim, C. M.; Gong, U. S.; Kim, S. H.; Lee, J. P.; Rhoo, H. C.; Kim, M. S.; Ryoo, S. K.; Choi, C. H.; Oh, K. I

    1999-12-01

    One of the important issues related to the nuclear safety is in-service inspection of reactor pressure vessel (RPV). A remote controlled automatic ultrasonic method is applied to the inspection. At present the automatic ultrasonic inspection system owned by KAERI is interrupted due to degradation of parts. In order to resume field inspection new remote control system for the equipment was designed and installed to the existing equipment. New ultrasonic sensors and their modules for RPV inspection were designed and fabricated in accordance with the new requirements of the inspection codes. Ultrasonic sensors were verified for the use in the RPV inspection. (autho0008.

  2. Magnetic non-destructive evaluation of hardening of cold rolled reactor pressure vessel steel

    Science.gov (United States)

    Wang, Xuejiao; Qiang, Wenjiang; Shu, Guogang

    2017-08-01

    Non-destructive test (NDT) of reactor pressure vessel (RPV) steel is urgently required due to the life extension program of nuclear power plant. Here magnetic NDT of cold rolled RPV steel is studied. The strength, hardness and coercivity increase with the increasing deformation, and a good linear correlation between the increment of coercivity, hardness and yield strength is found, which may be helpful to develop magnetic NDT of degradation of RPV steel. It is also found that besides dislocation density, the distribution of dislocations may affect coercivity as well.

  3. Evaluation of dynamic fracture toughness for Yong Gwang unit 5 reactor pressure vessel materials (Baseline Tests)

    Energy Technology Data Exchange (ETDEWEB)

    Chi Se Hwan; Kim, Joo Hag; Hong, Jun Hwa; Kwon, Sun Chil; Lee, Bong Sang [Korea Atomic Energy Research Institute, Taejon (Korea)

    1999-10-01

    The dynamic fracture toughness (K{sub d}) of intermediate shell and its weld in SA 508 CI. 3 Yong Gwang 5 reactor pressure vessel was determined and evaluated. Precracked thirty six Charpy specimens were tested by using an instrumented impact tester. The purpose of present work is to evaluate and confirm the un-irradiated dynamic fracture toughness and to provide pre-irradiation baseline data for future evaluation on dynamic fracture toughness change during operation. 18 refs., 5 figs., 5 tabs. (Author)

  4. Deformation Characteristics and Sealing Performance of Metallic O-rings for a Reactor Pressure Vessel

    OpenAIRE

    Shen, Mingxue; PENG, Xudong; Xie, Linjun; Meng, Xiangkai; Li, Xinggen

    2016-01-01

    This paper provides a reference to determine the seal performance of metallic O-rings for a reactor pressure vessel (RPV). A nonlinear elastic-plastic model of an O-ring was constructed by the finite element method to analyze its intrinsic properties. It is also validated by experiments on scaled samples. The effects of the compression ratio, the geometrical parameters of the O-ring, and the structure parameters of the groove on the flange are discussed in detail. The results showed that the ...

  5. Conditioning of waste from the dismantling of reactor pressure vessel components and of core components

    Energy Technology Data Exchange (ETDEWEB)

    Cleve, R.; Oldiges, O.; Splittler, U.

    2001-07-01

    When power reactors are shut down, the treatment of the core components and of the reactor pressure vessel components constitutes a particular task. Due to its special radiological characteristics, this waste must basically be handled using remote-control equipment with regard to the treatment. For its conditioning in a manner appropriate for the final storage, the waste must be dried and packed into suitable packing drums. The solution implemented by GNS and DSD in order to treat this waste from the Wuergassen nuclear power plant is described in the present contribution. (orig.)

  6. Review of the Palisades pressure vessel accumulated fluence estimate and of the least squares methodology employed

    Energy Technology Data Exchange (ETDEWEB)

    Griffin, P.J.

    1998-05-01

    This report provides a review of the Palisades submittal to the Nuclear Regulatory Commission requesting endorsement of their accumulated neutron fluence estimates based on a least squares adjustment methodology. This review highlights some minor issues in the applied methodology and provides some recommendations for future work. The overall conclusion is that the Palisades fluence estimation methodology provides a reasonable approach to a {open_quotes}best estimate{close_quotes} of the accumulated pressure vessel neutron fluence and is consistent with the state-of-the-art analysis as detailed in community consensus ASTM standards.

  7. Remote through-wall sampling of the Trawsfynydd reactor pressure vessel: an overview

    Energy Technology Data Exchange (ETDEWEB)

    Curry, A.; Clayton, R. [Magnox Electric, Berkeley (United Kingdom)

    1997-02-01

    This paper summarizes the application of robotic equipment for gaining access to, and removing through-wall samples, from, welds of the reactor pressure vessel at Trawsfyndd power station. The environment, which presents hazards due to ionising radiation, radioactive contamination and asbestos-bearing materials is described. The means of access, by use of remote vehicles with robotic manipulators supported by additional vehicles, it reviewed. The use of abrasive water jet cutting for sample removal is introduced. The relative advantages and disadvantages of this technique are discussed. (Author).

  8. Remote through-wall sampling of the Trawsfynydd reactor pressure vessel: an overview

    Energy Technology Data Exchange (ETDEWEB)

    Curry, A.; Clayton, R. [Magnox Electric, Dartford (United Kingdom). Remote Operations

    1996-12-31

    This paper summarises the application of robotic equipment for gaining access to and removing through-wall samples from welds of the reactor pressure vessel at Trawsfynydd power station. The environment, which presents hazards due to ionising radiation, radioactive contamination and asbestos bearing materials is described. The means of access, by use of remote vehicles complete with robotic manipulators supported by additional vehicles, is reviewed. The use of Abrasive Water Jet Cutting for sample removal is introduced. The relative advantages and disadvantages of this technique are discussed. (UK).

  9. Fully coupled, hygro-thermo-mechanical sensitivity analysis of a pre-stressed concrete pressure vessel

    OpenAIRE

    Davie, C.T.; Pearce, C.J.; Bićanić, N.

    2014-01-01

    Following a recent world wide resurgence in the desire to build and operate nuclear power stations as a response to rising energy demands and global plans to reduce carbon emissions, and in the light of recent events such as those at the Fukushima Dai-ichi nuclear power plant in Japan, which have raised questions of safety, this work has investigated the long term behaviour of concrete nuclear power plant structures.\\ud A case example of a typical pre-stressed concrete pressure vessel (PCPV),...

  10. Towards an Ultrasonic Guided Wave Procedure for Health Monitoring of Composite Vessels: Application to Hydrogen-Powered Aircraft

    Directory of Open Access Journals (Sweden)

    Slah Yaacoubi

    2017-09-01

    Full Text Available This paper presents an overview and description of the approach to be used to investigate the behavior and the defect sensitivity of various ultrasonic guided wave (UGW modes propagating specifically in composite cylindrical vessels in the framework of the safety of hydrogen energy transportation such as hydrogen-powered aircrafts. These structures which consist of thick and multi-layer composites are envisioned for housing hydrogen gas at high pressures. Due to safety concerns associated with a weakened structure, structural health monitoring techniques are needed. A procedure for optimizing damage detection in these structural types is presented. It is shown that a finite element method can help identify useful experimental parameters including frequency range, excitation type, and receiver placement.

  11. Inspection of dissimilar metal welds in reactor pressure vessels in Spain

    Energy Technology Data Exchange (ETDEWEB)

    Gadea, J.R.; Regidor, J.J.; Pelaez, J.A.; Serrano, P. [Tecnatom, S.A., San Sebastian de los Reyes, Madrid (Spain)

    2011-07-01

    MRP-139 recommendations for inspection of dissimilar metal (DM) welds in PWR vessels were launched in the last years in the USA. Basically, it increases the frequency of the examinations in these type of welds, with major emphasis in the hot loops, adding one intermediate inspection at the ten years interval in outlet nozzles. The spanish nuclear power plants (NPP's) have begun the implementation of this type of inspections on the vessel nozzles DM welds. As this type of inspections could have an impact in the critical path duration of the outage, it is necessary the use of a mechanical equipment able to examine the nozzles DM welds in a short vessel occupation time (VOT) with high quality, qualified techniques and minimum requirements of the refuelling platform. Tecnatom undertook the design and development of a new more advanced equipment, named TENIS-DM, for implementing the reactor pressure vessel (RPV) nozzles examination. This equipment was designed in order to accomplish the stringent requirements and the updated examination techniques; it was used for the inspection of the DM welds of Asco 1 NPP inlet and outlet nozzles in March 2011. Examination techniques and procedures were qualified through the GRUVAL validation program, based on ENIC methodology. Mechanical scanner was equipped with a large number of examination probes, and TV cameras -for visual inspection and also for monitoring the ultrasonic inspections. A remote operated submarine was also used to give support to the operational personnel during the manipulation of the equipment and its movements from one nozzle to the others. During two months before the inspection, tests of the complete inspection system were made on a nozzle mock-up installed in a 4 meters deep well at Tecnatom's facilities; this scenario was also used during the training sessions of the inspection crew. The defined technical and practical objectives were achieved: use of qualified techniques and minimal impact on the

  12. Hydrogen Cracking and Stress Corrosion of Pressure Vessel Steel ASTM A543

    Science.gov (United States)

    AlShawaf, Ali Hamad

    The purpose of conducting this research is to develop fundamental understanding of the weldability of the modern Quenched and Tempered High Strength Low Alloy (Q&T HSLA) steel, regarding the cracking behavior and susceptibility to environmental cracking in the base metal and in the heat affected zone (HAZ) when welded. A number of leaking cracks developed in the girth welds of the pressure vessel after a short time of upgrading the material from plain carbon steel to Q&T HSLA steel. The new vessels were constructed to increase the production of the plant and also to save weight for the larger pressure vessel. The results of this research study will be used to identify safe welding procedure and design more weldable material. A standardized weldability test known as implant test was constructed and used to study the susceptibility of the Q&T HSLA steel to hydrogen cracking. The charged hydrogen content for each weld was recorded against the applied load during weldability testing. The lack of understanding in detail of the interaction between hydrogen and each HAZ subzone in implant testing led to the need of developing the test to obtain more data about the weldability. The HAZ subzones were produced using two techniques: standard furnace and GleebleRTM machine. These produced subzones were pre-charged with hydrogen to different levels of concentration. The hydrogen charging on the samples simulates prior exposure of the material to high humidity environment during welding process. Fractographical and microstructural characterization of the HAZ subzones were conducted using techniques such as SEM (Scanning Electron Microscopy). A modified implant test using the mechanical tensile machine was also used to observe the effects of the hydrogen on the cracking behavior of each HAZ subzone. All the experimental weldability works were simulated and validated using a commercial computational software, SYSWELD. The computational simulation of implant testing of Q&T HSLA

  13. Blood Pressure Control in Aging Predicts Cerebral Atrophy Related to Small-Vessel White Matter Lesions

    Directory of Open Access Journals (Sweden)

    Kyle C. Kern

    2017-05-01

    Full Text Available Cerebral small-vessel damage manifests as white matter hyperintensities and cerebral atrophy on brain MRI and is associated with aging, cognitive decline and dementia. We sought to examine the interrelationship of these imaging biomarkers and the influence of hypertension in older individuals. We used a multivariate spatial covariance neuroimaging technique to localize the effects of white matter lesion load on regional gray matter volume and assessed the role of blood pressure control, age and education on this relationship. Using a case-control design matching for age, gender, and educational attainment we selected 64 participants with normal blood pressure, controlled hypertension or uncontrolled hypertension from the Northern Manhattan Study cohort. We applied gray matter voxel-based morphometry with the scaled subprofile model to (1 identify regional covariance patterns of gray matter volume differences associated with white matter lesion load, (2 compare this relationship across blood pressure groups, and (3 relate it to cognitive performance. In this group of participants aged 60–86 years, we identified a pattern of reduced gray matter volume associated with white matter lesion load in bilateral temporal-parietal regions with relative preservation of volume in the basal forebrain, thalami and cingulate cortex. This pattern was expressed most in the uncontrolled hypertension group and least in the normotensives, but was also more evident in older and more educated individuals. Expression of this pattern was associated with worse performance in executive function and memory. In summary, white matter lesions from small-vessel disease are associated with a regional pattern of gray matter atrophy that is mitigated by blood pressure control, exacerbated by aging, and associated with cognitive performance.

  14. Blood Pressure Control in Aging Predicts Cerebral Atrophy Related to Small-Vessel White Matter Lesions.

    Science.gov (United States)

    Kern, Kyle C; Wright, Clinton B; Bergfield, Kaitlin L; Fitzhugh, Megan C; Chen, Kewei; Moeller, James R; Nabizadeh, Nooshin; Elkind, Mitchell S V; Sacco, Ralph L; Stern, Yaakov; DeCarli, Charles S; Alexander, Gene E

    2017-01-01

    Cerebral small-vessel damage manifests as white matter hyperintensities and cerebral atrophy on brain MRI and is associated with aging, cognitive decline and dementia. We sought to examine the interrelationship of these imaging biomarkers and the influence of hypertension in older individuals. We used a multivariate spatial covariance neuroimaging technique to localize the effects of white matter lesion load on regional gray matter volume and assessed the role of blood pressure control, age and education on this relationship. Using a case-control design matching for age, gender, and educational attainment we selected 64 participants with normal blood pressure, controlled hypertension or uncontrolled hypertension from the Northern Manhattan Study cohort. We applied gray matter voxel-based morphometry with the scaled subprofile model to (1) identify regional covariance patterns of gray matter volume differences associated with white matter lesion load, (2) compare this relationship across blood pressure groups, and (3) relate it to cognitive performance. In this group of participants aged 60-86 years, we identified a pattern of reduced gray matter volume associated with white matter lesion load in bilateral temporal-parietal regions with relative preservation of volume in the basal forebrain, thalami and cingulate cortex. This pattern was expressed most in the uncontrolled hypertension group and least in the normotensives, but was also more evident in older and more educated individuals. Expression of this pattern was associated with worse performance in executive function and memory. In summary, white matter lesions from small-vessel disease are associated with a regional pattern of gray matter atrophy that is mitigated by blood pressure control, exacerbated by aging, and associated with cognitive performance.

  15. Initial Probabilistic Evaluation of Reactor Pressure Vessel Fracture with Grizzly and Raven

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, Benjamin [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hoffman, William [Univ. of Idaho, Moscow, ID (United States); Sen, Sonat [Idaho National Lab. (INL), Idaho Falls, ID (United States); Rabiti, Cristian [Idaho National Lab. (INL), Idaho Falls, ID (United States); Dickson, Terry [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bass, Richard [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-10-01

    The Grizzly code is being developed with the goal of creating a general tool that can be applied to study a variety of degradation mechanisms in nuclear power plant components. The first application of Grizzly has been to study fracture in embrittled reactor pressure vessels (RPVs). Grizzly can be used to model the thermal/mechanical response of an RPV under transient conditions that would be observed in a pressurized thermal shock (PTS) scenario. The global response of the vessel provides boundary conditions for local models of the material in the vicinity of a flaw. Fracture domain integrals are computed to obtain stress intensity factors, which can in turn be used to assess whether a fracture would initiate at a pre-existing flaw. These capabilities have been demonstrated previously. A typical RPV is likely to contain a large population of pre-existing flaws introduced during the manufacturing process. This flaw population is characterized stastistically through probability density functions of the flaw distributions. The use of probabilistic techniques is necessary to assess the likelihood of crack initiation during a transient event. This report documents initial work to perform probabilistic analysis of RPV fracture during a PTS event using a combination of the RAVEN risk analysis code and Grizzly. This work is limited in scope, considering only a single flaw with deterministic geometry, but with uncertainty introduced in the parameters that influence fracture toughness. These results are benchmarked against equivalent models run in the FAVOR code. When fully developed, the RAVEN/Grizzly methodology for modeling probabilistic fracture in RPVs will provide a general capability that can be used to consider a wider variety of vessel and flaw conditions that are difficult to consider with current tools. In addition, this will provide access to advanced probabilistic techniques provided by RAVEN, including adaptive sampling and parallelism, which can dramatically

  16. Standard Master Matrix for Light-Water Reactor Pressure Vessel Surveillance Standards, E706(0)

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2002-01-01

    1.1 This master matrix standard describes a series of standard practices, guides, and methods for the prediction of neutron-induced changes in light-water reactor (LWR) pressure vessel (PV) and support structure steels throughout a pressure vessel's service life (Fig. 1). Some of these are existing ASTM standards, some are ASTM standards that have been modified, and some are proposed ASTM standards. General requirements of content and consistency are discussed in Section 6 . More detailed writers' and users' information, justification, and specific requirements for the nine practices, ten guides, and three methods are provided in Sections 3-5. Referenced documents are discussed in Section 2. The summary-type information that is provided in Sections 3 and 4 is essential for establishing proper understanding and communications between the writers and users of this set of matrix standards. It was extracted from the referenced documents, Section 2 and references (1-106) for use by individual writers and users. 1...

  17. Digital Cellular Solid Pressure Vessels: A Novel Approach for Human Habitation in Space

    Science.gov (United States)

    Cellucci, Daniel; Jenett, Benjamin; Cheung, Kenneth C.

    2017-01-01

    It is widely assumed that human exploration beyond Earth's orbit will require vehicles capable of providing long duration habitats that simulate an Earth-like environment - consistent artificial gravity, breathable atmosphere, and sufficient living space- while requiring the minimum possible launch mass. This paper examines how the qualities of digital cellular solids - high-performance, repairability, reconfigurability, tunable mechanical response - allow the accomplishment of long-duration habitat objectives at a fraction of the mass required for traditional structural technologies. To illustrate the impact digital cellular solids could make as a replacement to conventional habitat subsystems, we compare recent proposed deep space habitat structural systems with a digital cellular solids pressure vessel design that consists of a carbon fiber reinforced polymer (CFRP) digital cellular solid cylindrical framework that is lined with an ultra-high molecular weight polyethylene (UHMWPE) skin. We use the analytical treatment of a linear specific modulus scaling cellular solid to find the minimum mass pressure vessel for a structure and find that, for equivalent habitable volume and appropriate safety factors, the use of digital cellular solids provides clear methods for producing structures that are not only repairable and reconfigurable, but also higher performance than their conventionally manufactured counterparts.

  18. Effect of Macrosegregation on the Microstructure and Mechanical Properties of a Pressure-Vessel Steel

    Science.gov (United States)

    Yan, Guanghua; Han, Lizhan; Li, Chuanwei; Luo, Xiaomeng; Gu, Jianfeng

    2017-07-01

    Macrosegregation refers to the chemical segregation, which occurs quite commonly in the large forgings such as nuclear reactor pressure vessel. This work assesses the effect of macrosegregation and homogenization treatment on the mechanical properties of a pressure-vessel steel (SA508 Gr.3). It was found that the primary reason for the inhomogeneity of the microstructure was the segregation of Mn, Mo, and Ni. Martensite, and coarse upper bainite with M-A (martensite-austenite) islands have been obtained, respectively, in the positive and negative segregation zone during a simulated quenching process. During tempering, the carbon-rich M-A islands decomposed into a mixture of ferrite and numerous carbides which deteriorated the toughness of the material. The segregation has been substantially minimized by a homogenizing treatment. The results indicate that the material homogenized has a higher impact toughness than the material with segregation, due to the reduction in M-A island in the negative segregation zone. It can be concluded that the microstructure and mechanical properties have been improved remarkably by means of homogenization treatment.

  19. A continuum damage analysis of hydrogen attack in a 2.25Cr–1Mo pressure vessel

    NARCIS (Netherlands)

    Burg, M.W.D. van der; Giessen, E. van der; Tvergaard, V.

    1998-01-01

    A micromechanically based continuum damage model is presented to analyze the stress, temperature and hydrogen pressure dependent material degradation process termed hydrogen attack, inside a pressure vessel. Hydrogen attack (HA) is the damage process of grain boundary facets due to a chemical

  20. 46 CFR 53.01-3 - Adoption of section IV of the ASME Boiler and Pressure Vessel Code.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Adoption of section IV of the ASME Boiler and Pressure...) MARINE ENGINEERING HEATING BOILERS General Requirements § 53.01-3 Adoption of section IV of the ASME..., and stamped in accordance with section IV of the ASME Boiler and Pressure Vessel Code (incorporated by...

  1. 46 CFR 52.01-2 - Adoption of section I of the ASME Boiler and Pressure Vessel Code.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Adoption of section I of the ASME Boiler and Pressure...) MARINE ENGINEERING POWER BOILERS General Requirements § 52.01-2 Adoption of section I of the ASME Boiler..., inspected, tested, and stamped in accordance with section I of the ASME Boiler and Pressure Vessel Code...

  2. Effect of Heat Flux on Creep Stresses of Thick-Walled Cylindrical Pressure Vessels

    Directory of Open Access Journals (Sweden)

    Mosayeb Davoudi Kashkoli

    2014-06-01

    Full Text Available Assuming that the thermo-creep response of the material is governed by Norton’s law, an analytical solution is presented for the calculation of time-dependent creep stresses and displacements of homogeneous thick-walled cylindrical pressure vessels. For the stress analysis in a homogeneous pressure vessel, having material creep behavior, the solutions of the stresses at a time equal to zero (i.e. the initial stress state are needed. This corresponds to the solution of materials with linear elastic behavior. Therefore, using equations of equilibrium, stress-strain and strain-displacement, a differential equation for displacement is obtained and then the stresses at a time equal to zero are calculated. Using Norton’s law in the multi-axial form in conjunction with the above-mentioned equations in the rate form, the radial displacement rate is obtained and then the radial, circumferential and axial creep stress rates are calculated. When the stress rates are known, the stresses at any time are calculated iteratively. The analytical solution is obtained for the conditions of plane strain and plane stress. The thermal loading is as follows: inner surface is exposed to a uniform heat flux, and the outer surface is exposed to an airstream. The heat conduction equation for the one-dimensional problem in polar coordinates is used to obtain temperature distribution in the cylinder. The pressure, inner radius and outer radius are considered constant. Material properties are considered as constant. Following this, profiles are plotted for the radial displacements, radial stress, circumferential stress and axial stress as a function of radial direction and time.

  3. Measurement of inner defects and out of plane deformation of pressure vessel in piping of circulation system using shearography

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Chan Geun; Kim, Hyun Ho; Jung, Hyun Il; Choi, Tae Ho; Jung, Hyun Chul; Kim, Kyeog Suk [Chosun University, Gwangju (Korea, Republic of)

    2014-10-15

    Wall thinning defects can occur in the pressure vessels used in a variety of industries. Such defects are related to the flow velocity. Considering the fact that such vessels constitute up to 70 or 80% of the plant structures in a power plant, it is important to measure internal defects as part of a safety evaluation. In this study, optical measurement were applied in a non-destructive evaluation using shearography to ensure the safety and improve the reliability of a power plant through the non-contact, non-destructive evaluation of pressure vessels. In order to verify whether the pressure vessels contained faults, experimental and analytical investigation were conducted to measure any internal defects and out-of-plane deformation from inner temperature changes and pressure changes in the piping of the circulation system. The most important factors in this research were the thickness, width, and length of a defect. An increase in these could confirm an increase in the deformation. Thus, internal defects in a pressure vessel were measured using shearography, which made it possible to ensure the reliability and integrity of the pipe.

  4. Assessment of materials technology of pressure vessels and piping for coal conversion systems

    Energy Technology Data Exchange (ETDEWEB)

    Canonico, D.A.; Cooper, R.H.; Foster, B.E.; McClung, R.W.; Nanstad, R.K.; Robinson, G.C.; Slaughter, G.M.

    1978-08-01

    The current technology of the materials, fabrication, and inspection of pressure vessels and piping for commercial coal conversion systems is reviewed. Comparison is made between the various codes applicable to these conversion systems. Areas of concern, such as material compatibility and fracture toughness, are cited. Recommendations are made that should increase the reliability of these components, the failure of which would result in a major outage of the plant. We believe that to date most of the current studies of various competing processes have emphasized the capital cost aspects to show potential competition with other energy sources but have not adequately examined the influence of design features on both potential maintenance and disruptive failure costs. It appears, for example, that the choice of vessel size (which is dictated by single vs multiple train process designs) has been examined primarily from the standpoint of capital costs. Maintenance, operation, relative part load capability, and relative probability of failure are unanswered questions. The materials having the most favorable mechanical properties and costs, unfortunately, are sensitive to various embrittling phenomena.

  5. Pressure vessels design methods using the codes, fracture mechanics and multiaxial fatigue

    Directory of Open Access Journals (Sweden)

    Fatima Majid

    2016-10-01

    Full Text Available This paper gives a highlight about pressure vessel (PV methods of design to initiate new engineers and new researchers to understand the basics and to have a summary about the knowhow of PV design. This understanding will contribute to enhance their knowledge in the selection of the appropriate method. There are several types of tanks distinguished by the operating pressure, temperature and the safety system to predict. The selection of one or the other of these tanks depends on environmental regulations, the geographic location and the used materials. The design theory of PVs is very detailed in various codes and standards API, such as ASME, CODAP ... as well as the standards of material selection such as EN 10025 or EN 10028. While designing a PV, we must design the fatigue of its material through the different methods and theories, we can find in the literature, and specific codes. In this work, a focus on the fatigue lifetime calculation through fracture mechanics theory and the different methods found in the ASME VIII DIV 2, the API 579-1 and EN 13445-3, Annex B, will be detailed by giving a comparison between these methods. In many articles in the literature the uniaxial fatigue has been very detailed. Meanwhile, the multiaxial effect has not been considered as it must be. In this paper we will lead a discussion about the biaxial fatigue due to cyclic pressure in thick-walled PV. Besides, an overview of multiaxial fatigue in PVs is detailed

  6. Characterisation of creep cavitation damage in a stainless steel pressure vessel using small angle neutron scattering

    CERN Document Server

    Bouchard, P J; Treimer, W

    2002-01-01

    Grain-boundary cavitation is the dominant failure mode associated with initiation of reheat cracking, which has been widely observed in austenitic stainless steel pressure vessels operating at temperatures within the creep range (>450 C). Small angle neutron scattering (SANS) experiments at the LLB PAXE instrument (Saclay) and the V12 double-crystal diffractometer of the HMI-BENSC facility (Berlin) are used to characterise cavitation damage (in the size range R=10-2000 nm) in a variety of creep specimens extracted from ex-service plant. Factors that affect the evolution of cavities and the cavity-size distribution are discussed. The results demonstrate that SANS techniques have the potential to quantify the development of creep damage in type-316H stainless steel, and thereby link microstructural damage with ductility-exhaustion models of reheat cracking. (orig.)

  7. Study of a neutron irradiated reactor pressure vessel steel by X-ray absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Cammelli, S. [LWV, NES, Paul Scherrer Institute, 5232 Villigen PSI (Switzerland)], E-mail: sebastiano.cammelli@psi.ch; Degueldre, C.; Kuri, G.; Bertsch, J. [LWV, NES, Paul Scherrer Institute, 5232 Villigen PSI (Switzerland)

    2008-11-15

    Reactor pressure vessel (RPV) reference steel samples submitted to neutron irradiations followed by thermal annealing were investigated by X-ray absorption fine structure (XAFS) spectroscopy. Several studies revealed that Cu and Ni impurities can form nanoclusters. In the unirradiated sample and in the only-irradiated sample no significant clustering is detected. In all irradiated and subsequently annealed samples increases of Cu and Ni atom densities are recorded around the absorber. Furthermore, the density of Cu and Ni atoms determined in the first and second shells around the absorber is found to be affected by the irradiation and annealing treatment. The comparison of the XAFS data at Cu and Ni K-edges shows that these elements reside in arrangements similar to bcc Fe. However, the local irradiation damage yields vacancy fractions which were determined from the analysis of XAFS data with a precision of {approx}5%.

  8. Stress Corrosion Cracking and Fatigue Crack Growth Studies Pertinent to Spacecraft and Booster Pressure Vessels

    Science.gov (United States)

    Hall, L. R.; Finger, R. W.

    1972-01-01

    This experimental program was divided into two parts. The first part evaluated stress corrosion cracking in 2219-T87 aluminum and 5Al-2.5Sn (ELI) titanium alloy plate and weld metal. Both uniform height double cantilever beam and surface flawed specimens were tested in environments normally encountered during the fabrication and operation of pressure vessels in spacecraft and booster systems. The second part studied compatibility of material-environment combinations suitable for high energy upper stage propulsion systems. Surface flawed specimens having thicknesses representative of minimum gage fuel and oxidizer tanks were tested. Titanium alloys 5Al-2.5Sn (ELI), 6Al-4V annealed, and 6Al-4V STA were tested in both liquid and gaseous methane. Aluminum alloy 2219 in the T87 and T6E46 condition was tested in fluorine, a fluorine-oxygen mixture, and methane. Results were evaluated using modified linear elastic fracture mechanics parameters.

  9. The influence of fire exposure on austenitic stainless steel for pressure vessel fitness-for-service assessment: Experimental research

    Science.gov (United States)

    Li, Bo; Shu, Wenhua; Zuo, Yantian

    2017-04-01

    The austenitic stainless steels are widely applied to pressure vessel manufacturing. The fire accident risk exists in almost all the industrial chemical plants. It is necessary to make safety evaluation on the chemical equipment including pressure vessels after fire. Therefore, the present research was conducted on the influences of fire exposure testing under different thermal conditions on the mechanical performance evolution of S30408 austenitic stainless steel for pressure vessel equipment. The metallurgical analysis described typical appearances in micro-structure observed in the material suffered by fire exposure. Moreover, the quantitative degradation of mechanical properties was investigated. The material thermal degradation mechanism and fitness-for-service assessment process of fire damage were further discussed.

  10. Preliminary investigation of an ultrasound method for estimating pressure changes in deep-positioned vessels

    DEFF Research Database (Denmark)

    Olesen, Jacob Bjerring; Villagómez Hoyos, Carlos Armando; Traberg, Marie Sand

    2016-01-01

    This paper presents a method for measuring pressure changes in deep-tissue vessels using vector velocity ultrasound data. The large penetration depth is ensured by acquiring data using a low frequency phased array transducer. Vascular pressure changes are then calculated from 2-D angle...... varying from -40 Pa to 15 Pa with a standard deviation of 32%, and a bias of 25% found relative to the peak simulated pressure drop. This preliminary study shows that pressure can be estimated non-invasively to a depth that enables cardiac scans, and thereby, the possibility of detecting the pressure...

  11. Spin Forming Aluminum Crew Module (CM) Metallic Aft Pressure Vessel Bulkhead (APVBH) - Phase II

    Science.gov (United States)

    Hoffman, Eric K.; Domack, Marcia S.; Torres, Pablo D.; McGill, Preston B.; Tayon, Wesley A.; Bennett, Jay E.; Murphy, Joseph T.

    2015-01-01

    The principal focus of this project was to assist the Multi-Purpose Crew Vehicle (MPCV) Program in developing a spin forming fabrication process for manufacture of the Orion crew module (CM) aft pressure vessel bulkhead. The spin forming process will enable a single piece aluminum (Al) alloy 2219 aft bulkhead resulting in the elimination of the current multiple piece welded construction, simplify CM fabrication, and lead to an enhanced design. Phase I (NASA TM-2014-218163 (1)) of this assessment explored spin forming the single-piece CM forward pressure vessel bulkhead. The Orion MPCV Program and Lockheed Martin (LM) recently made two critical decisions relative to the NESC Phase I work scope: (1) LM selected the spin forming process to manufacture a single-piece aft bulkhead for the Orion CM, and (2) the aft bulkhead will be manufactured from Al 2219. Based on the Program's new emphasis related to the spin forming process, the NESC was asked to conduct a Phase II assessment to assist in the LM manufacture of the aft bulkhead and to conduct a feasibility study into spin forming the Orion CM cone. This activity was approved on June 19, 2013. Dr. Robert Piascik, NASA Technical Fellow for Materials at the Langley Research Center (LaRC), was selected to lead this assessment. The project plan was approved by the NASA Engineering and Safety Center (NESC) Review Board (NRB) on July 18, 2013. The primary stakeholders for this assessment were the NASA and LM MPCV Program offices. Additional benefactors are commercial launch providers developing CM concepts.

  12. Probabilistic Fracture Mechanics of Reactor Pressure Vessels with Populations of Flaws

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, Benjamin [Idaho National Lab. (INL), Idaho Falls, ID (United States); Backman, Marie [Univ. of Tennessee, Knoxville, TN (United States); Williams, Paul [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hoffman, William [Idaho National Lab. (INL), Idaho Falls, ID (United States); Alfonsi, Andrea [Idaho National Lab. (INL), Idaho Falls, ID (United States); Dickson, Terry [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bass, B. Richard [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Klasky, Hilda [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-01

    This report documents recent progress in developing a tool that uses the Grizzly and RAVEN codes to perform probabilistic fracture mechanics analyses of reactor pressure vessels in light water reactor nuclear power plants. The Grizzly code is being developed with the goal of creating a general tool that can be applied to study a variety of degradation mechanisms in nuclear power plant components. Because of the central role of the reactor pressure vessel (RPV) in a nuclear power plant, particular emphasis is being placed on developing capabilities to model fracture in embrittled RPVs to aid in the process surrounding decision making relating to life extension of existing plants. A typical RPV contains a large population of pre-existing flaws introduced during the manufacturing process. The use of probabilistic techniques is necessary to assess the likelihood of crack initiation at one or more of these flaws during a transient event. This report documents development and initial testing of a capability to perform probabilistic fracture mechanics of large populations of flaws in RPVs using reduced order models to compute fracture parameters. The work documented here builds on prior efforts to perform probabilistic analyses of a single flaw with uncertain parameters, as well as earlier work to develop deterministic capabilities to model the thermo-mechanical response of the RPV under transient events, and compute fracture mechanics parameters at locations of pre-defined flaws. The capabilities developed as part of this work provide a foundation for future work, which will develop a platform that provides the flexibility needed to consider scenarios that cannot be addressed with the tools used in current practice.

  13. Current understanding on the neutron irradiation embrittlement of BWR reactor pressure vessel steels in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Asano, K.; Nishiyama, T. [TEPCO (Japan); Soneda, N.; Dohi, K.; Nishida, K.; Nomoto, A. [CRIEPI (Japan); Ohta, T. [Japan Atomic Power Co. (Japan); Ishimaru, Y. [Chugoku EPCO (Japan); Yoneda, H. [Hokuriku EPCO (Japan); Lida, J. [Tohoku EPCO (Japan); Yuya, H. [Chubu EPCO (Japan)

    2011-07-01

    Neutron irradiation embrittlement of reactor pressure vessel (RPV) steels has been of concern primarily for the pressurized water reactors (PWRs). After long operation experiences, we are now becoming aware of the situation that the neutron irradiation embrittlement is also of concern for some of the boiling water reactors (BWRs) particularly with Cu-containing RPV steels. The surveillance data of Cu-containing BWR RPV steels show relatively larger shift in ductile-to-brittle transition temperature of fracture toughness than predicted by the embrittlement correlation method developed in late eighties and early nineties. Accurate evaluation of the amount of embrittlement is now very important for long-term operation of BWRs. In this paper, we will describe the neutron irradiation embrittlement of BWR RPVs in Japan. Some of the materials that show relatively large transition temperature shifts are investigated to understand the causes of embrittlement using state-of-the-art microstructural characterization techniques. Furthermore, some archive materials of such RPVs are irradiated in a material testing reactor with high neutron flux to understand the effect of flux on transition temperature shifts and corresponding microstructural changes. Microstructural evolution under irradiation, solute clustering in particular could explain the differences in transition temperature shift of the analyzed specimens. Larger BWR RPVs, which have larger water gaps, receive less neutron irradiation and harmful impurities in steels such as copper are well controlled since 1980 so irradiation embrittlement in BWR vessels can now be considered a concern only in old and small plants. All the new information obtained through these activities was considered in the development of new embrittlement correlation that is now adopted in JEAC 4201- 2007 of Japan Electric Association

  14. SURROGATE MODEL DEVELOPMENT AND VALIDATION FOR RELIABILITY ANALYSIS OF REACTOR PRESSURE VESSELS

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, William M.; Riley, Matthew E.; Spencer, Benjamin W.

    2016-07-01

    In nuclear light water reactors (LWRs), the reactor coolant, core and shroud are contained within a massive, thick walled steel vessel known as a reactor pressure vessel (RPV). Given the tremendous size of these structures, RPVs typically contain a large population of pre-existing flaws introduced in the manufacturing process. After many years of operation, irradiation-induced embrittlement makes these vessels increasingly susceptible to fracture initiation at the locations of the pre-existing flaws. Because of the uncertainty in the loading conditions, flaw characteristics and material properties, probabilistic methods are widely accepted and used in assessing RPV integrity. The Fracture Analysis of Vessels – Oak Ridge (FAVOR) computer program developed by researchers at Oak Ridge National Laboratory is widely used for this purpose. This program can be used in order to perform deterministic and probabilistic risk-informed analyses of the structural integrity of an RPV subjected to a range of thermal-hydraulic events. FAVOR uses a one-dimensional representation of the global response of the RPV, which is appropriate for the beltline region, which experiences the most embrittlement, and employs an influence coefficient technique to rapidly compute stress intensity factors for axis-aligned surface-breaking flaws. The Grizzly code is currently under development at Idaho National Laboratory (INL) to be used as a general multiphysics simulation tool to study a variety of degradation mechanisms in nuclear power plant components. The first application of Grizzly has been to study fracture in embrittled RPVs. Grizzly can be used to model the thermo-mechanical response of an RPV under transient conditions observed in a pressurized thermal shock (PTS) scenario. The global response of the vessel provides boundary conditions for local 3D models of the material in the vicinity of a flaw. Fracture domain integrals are computed to obtain stress intensity factors, which can in

  15. Effects of irradiation at lower temperature on the microstructure of Cr-Mo-V-alloyed reactor pressure vessel steel

    Energy Technology Data Exchange (ETDEWEB)

    Grosse, M.; Boehmert, J.; Gilles, R. [Hahn-Meitner-Institut Berlin GmbH (Germany)

    1998-10-01

    The microstructural damage process due to neutron irradiation [1] proceeds in two stages: - formation of displacement cascades - evolution of the microstructure by defect reactions. Continuing our systematic investigation about the microstructural changes of Russian reactor pressure vessel steel due to neutron irradiation the microstructure of two laboratory heats of the VVER 440-type reactor pressure vessel steel after irradiation at 60 C was studied by small angle neutron scattering (SANS). 60 C-irradiation differently changes the irradiation-induced microstructure in comparison with irradiation at reactor operation temperature and can, thus, provide new insights into the mechanisms of the irradiation damage. (orig.)

  16. NASA Lewis advanced individual pressure vessel (IPV) nickel/hydrogen technology

    Science.gov (United States)

    Smithrick, John J.; Britton, Doris L.

    Individual pressure vessel (IPV) nickel/hydrogen technology was advanced at NASA Lewis and under Lewis contracts. Some of the advancements are as follows: (1) to use 26% KOH electrolyte to improve cycle life and performance; (ii) to modify the state-of-the-art cell design to eliminate identified failure modes and further improve cycle life, and (iii) to develop a lightweight nickel electrode to reduce battery mass, hence reduce launch and/ or increase satellite payload. A breakthrough in the Low-Earth-Orbit (LEO) cycle life of individual pressure vessel nickel/hydrogen battery cells was reported. The cycle life of boiler plate cells containing 26% KOH electrolyte was about 40 000 accelerated LEO cycles at 80% depth-of-discharge (DOD) compared with 3500 cycles for cells containing 31% KOH. Results of the boiler plate cells tests have been validated at Naval Weapons Support Center, Crane, IN. Forty-eight Ah flight cells containing 26 and 31% KOH have undergone real time LEO cycle life testing at an 80% DOD, in 10 °C. The three cells containing 26% KOH failed on the average at cycle 19 500. The three cells containing 31% KOH failed on the average at cycle 6400. Validation testing of NASA Lewis 125 Ah advanced design IPV nickel/hydrogen flight cells is also being conducted at Naval Weapons Support Center, Crane, IN under a NASA Lewis contract. This consists of characterization, storage, and cycle-life testing. There was no capacity degradation after 52 days of storage with the cells in the discharged state, on open circuit, 0 °C, and a hydrogen pressure of 14.5 psia (1 atm). The catalyzed wall wick cells have been cycled for over 22 694 cycles with no cell failures in the continuing test. All three of the noncatalyzed wall wick cells failed (cycles 9588, 13 900 and 20 575). Cycle-life test results of the Fibrex nickel electrode has demonstrated the feasibility of an improved nickel electrode giving a higher specific energy nickel/hydrogen cell. A nickel

  17. The aging of pressurized water nuclear reactor vessels; Le vieillissement des cuves de reacteurs nucleaires a eau sous pression

    Energy Technology Data Exchange (ETDEWEB)

    Monin, L. [Autorite de Surete Nucleaire, Dir. des Equipements sous Pression Nucleaires, 75 - Paris (France); Monnot, B. [Institut de Radioprotection et de Surete Nucleaire (IRSN), Bureau d' Analyse des Materiels Mecaniques, 92 - Clamart (France)

    2009-07-15

    In pressurized water nuclear power plants, heat is produced by the fission of the uranium cores, a constituent of the fuel rods placed in the reactor core. This core formed by the set of fuel assemblies is contained In the reactor vessel. As a part of the second confinement barrier of the radioactive elements, the vessel enables the reactor core to be cooled the primary fluid, to be controlled by the control rods, and to be supervised. Its role is of prime importance for the safety of the plant. Its integrity must therefore be guaranteed and must be demonstrated under all operating conditions and for the entire duration of its operation. Contrary to other devices of the primary circuit, like the steam generators, the replacement of a vessel is not an operation considered by EDF. The working life of the facility is consequently linked to the justification of the suitability of the vessel's use. (author)

  18. Exploratory Study of Irradiation, Annealing, and Reirradiation Effects on American and Russian Reactor Pressure Vessel Steels

    Energy Technology Data Exchange (ETDEWEB)

    Chernobaeva, A.A., Kryukov, A.M., Nikolaev, Y.A., Korolev, Y.N. [Russian Research Centre Kurchatov Inst., Moscow (Russian Federation)], Sokolov, M.A., Nanstad, R.K. [Oak Ridge National Lab., TN (United States)

    1997-12-31

    One of the options to mitigate the effects of irradiation on reactor pressure vessels (RPVS) is to thermally anneal them to restore the toughness properties that have been degraded by neutron irradiation. even though a postirradiation anneal may be deemed successful, a critical aspect of continued RPV operation is the rate of embrittlement upon reirradiation. There are insufficient data available to allow for verification models of reirradiation embrittlement or for the development of a reliable predictive methodology. This is especially true in the case of fracture toughness data. Under the U.S.-Russia Joint Coordinating Committee for Civilian Nuclear Reactor Safety (JCCCNRS), Working Group 3 on Radiation Embrittlement, Structural Integrity, and Life Extension of Reactor Vessels and Supports agreed to conduct a comparative study of annealing and reirradiation effects on RPV steels. The working group agreed that each side would irradiate, anneal, reirradiate (if feasible), and test two materials of the other; so far, only charpy impact and tensile specimens have been included. Oak Ridge National Laboratory (ornl) conducted such a program (irradiation and annealing) with two weld metals representative of VVER-440 AND VVER-1000 RPVS, while the Russian Research Center-Kurchatov Institute (RRC-KI) conducted a program (irradiation,annealing, reirradiation, and reannealing) with Heavy-Section Steel Technology (HSST) program plate 02 and Heavy-Section Steel Irradiation (HSSI) program weld 73w. The results for each material from each laboratory are compared with those from the other laboratory. the ORNL experiments with the VVER welds included irradiation to about 1 x 10 (exp 19) N/SQ CM ({gt}1 MeV), while the RRC-KI experiments with the U.S. materials included irradiations from about 2 to 18 X 10 (exp 19) N/SQ CM ({gt}1 MeV).

  19. MRI Interscanner Agreement of the Association between the Susceptibility Vessel Sign and Histologic Composition of Thrombi.

    Science.gov (United States)

    Bourcier, Romain; Détraz, Lili; Serfaty, Jean Michel; Delasalle, Beatrice Guyomarch; Mirza, Mahmood; Derraz, Imad; Toulgoat, Frédérique; Naggara, Olivier; Toquet, Claire; Desal, Hubert

    2017-11-01

    The susceptibility vessel sign (SVS) on magnetic resonance imaging (MRI) is related to thrombus location, composition, and size in acute stroke. No previous study has determined its inter-MRI scanner variability. We aimed to compare the diagnostic accuracy in-vitro of four different MRI scanners for the characterization of histologic thrombus composition. Thirty-five manufactured thrombi analogs of different composition that were histologically categorized as fibrin-dominant, mixed, or red blood cell (RBC)-dominant were scanned on four different MRI units with T2* sequence. Nine radiologists, blinded to thrombus composition and MRI scanner model, classified twice, in a 2-week interval, the SVS of each thrombus as absent, questionable, or present. We calculated the weighted kappa with 95% confidence interval (CI), sensitivity, specificity and accuracy of the SVS on each MRI scanner to detect RBC-dominant thrombi. The SVS was present in 42%, absent in 33%, and questionable in 25% of thrombi. The interscanner agreement was moderate to good, ranging from .45 (CI: .37-.52) to .67 (CI: .61-.74). The correlation between the SVS and the thrombus composition was moderate (κ: .50 [CI: .44-.55]) to good κ: .76 ([CI: .72-.80]). Sensitivity, specificity, and accuracy to identify RBC-dominant clots were significantly different between MRI scanners (P composition varies significantly among MRI scanners. Normalization of T2*sequences between scanners may be needed to better predict thrombus composition in multicenter studies. Copyright © 2017 by the American Society of Neuroimaging.

  20. Microstructural changes of a thermally aged stainless steel submerged arc weld overlay cladding of nuclear reactor pressure vessels

    Science.gov (United States)

    Takeuchi, T.; Kameda, J.; Nagai, Y.; Toyama, T.; Matsukawa, Y.; Nishiyama, Y.; Onizawa, K.

    2012-06-01

    The effect of thermal aging on microstructural changes in stainless steel submerged arc weld-overlay cladding of reactor pressure vessels was investigated using atom probe tomography (APT). In as-received materials subjected to post-welding heat treatments (PWHTs), with a subsequent furnace cooling, a slight fluctuation of the Cr concentration was observed due to spinodal decomposition in the δ-ferrite phase but not in the austenitic phase. Thermal aging at 400 °C for 10,000 h caused not only an increase in the amplitude of spinodal decomposition but also the precipitation of G phases with composition ratios of Ni:Si:Mn = 16:7:6 in the δ-ferrite phase. The degree of the spinodal decomposition in the submerged arc weld sample was similar to that in the electroslag weld one reported previously. We also observed a carbide on the γ-austenite and δ-ferrite interface. There were no Cr depleted zones around the carbide.

  1. Does Physical Fitness Buffer the Relationship between Psychosocial Stress, Retinal Vessel Diameters, and Blood Pressure among Primary Schoolchildren?

    Directory of Open Access Journals (Sweden)

    Markus Gerber

    2016-01-01

    Full Text Available Background. Strong evidence exists showing that psychosocial stress plays an important part in the development of cardiovascular diseases. Because physical inactivity is associated with less favourable retinal vessel diameter and blood pressure profiles, this study explores whether physical fitness is able to buffer the negative effects of psychosocial stress on retinal vessel diameters and blood pressure in young children. Methods. 325 primary schoolchildren (51% girls, Mage=7.28 years took part in this cross-sectional research project. Retinal arteriolar diameters, retinal venular diameters, arteriolar to venular ratio, and systolic and diastolic blood pressure were assessed in all children. Interactions terms between physical fitness (performance in the 20 m shuttle run test and four indicators of psychosocial stress (parental reports of critical life events, family, peer and school stress were tested in a series of hierarchical regression analyses. Results. Critical life events and family, peer, and school-related stress were only weakly associated with retinal vessel diameters and blood pressure. No support was found for a stress-buffering effect of physical fitness. Conclusion. More research is needed with different age groups to find out if and from what age physical fitness can protect against arteriolar vessel narrowing and the occurrence of other cardiovascular disease risk factors.

  2. Analisis Remaining Life dan Penjadwalan Program Inspeksi pada Pressure Vessel dengan Menggunakan Metode Risk Based Inspection (RBI

    Directory of Open Access Journals (Sweden)

    Dyah Arina Wahyu Lillah

    2017-01-01

    Full Text Available Seiring perkembangan eksplorasi minyak dan gas bumi di dunia, perusahaan minyak dan gas di Indonesia juga turut berlomba-lomba untuk mendapatkan ladang minyak dan gas bumi sebanyak-banyaknya. Perkembangan ini turut dipengaruhi oleh aturan-aturan pemerintah mengenai keselamatan dan pencegahan bahaya baik pada unit yang dikelola maupun tenaga kerja pengelola. Untuk itu semua perlatan-peralatan (unit kerja harus dijamin kehandalaannya agar tidak menimbulkan bahaya baik bagi pekerja maupun lingkungan. Subjek penelitian dalam tugas akhir ini ialah pada pressure vessel yang dimiliki oleh Terminal LPG Semarang. Kemungkinan bahaya yang dapat menyebabkan kerusakan pada pressure vessel perlu dianalisis agar dapat meminimalkan resiko yang akan terjadi. Metode Risk Based Inspection (RBI diharapkan dapat meminimalkan resiko yang ada pada pressure vessel. Penilaian resiko dalam tugas akhir ini mengacu pada standar API RP 581. Untuk mengetahui besarnya resiko yang ada pada plant, maka terlebih dahulu harus dihitung besarnya probabilitas kegagalan dan konsekuensi apabila terjadi kegagalan. Langkah selanjutnya ialah membandingkan besarnya resiko yang didapat dengan target resiko yang dimiliki oleh perusahaan. Dari hasil perbandingan ini dapat diketahui tingkat resiko pressure vessel, sehingga dapat ditentukan jadwal inspeksi dan metode inspeksi yang tepat.

  3. Technology update: Nickel-hydrogen Common Pressure Vessel (CPV) 2.5V twin stack cell designs

    Science.gov (United States)

    Harvey, Tim; Miller, Lee

    1992-01-01

    Information is given in viewgraph form on the nickel hydrogen common pressure vessel (CPV) 2.5V twin stack cell designs. Information given includes an energy analysis, a CPV design comparison, a summary of CPV characterization testing, a comparison of discharge voltage among designs, and life test performance summaries.

  4. Does Physical Fitness Buffer the Relationship between Psychosocial Stress, Retinal Vessel Diameters, and Blood Pressure among Primary Schoolchildren?

    Science.gov (United States)

    Gerber, Markus; Endes, Katharina; Herrmann, Christian; Colledge, Flora; Brand, Serge; Donath, Lars; Faude, Oliver; Pühse, Uwe; Hanssen, Henner; Zahner, Lukas

    2016-01-01

    Background. Strong evidence exists showing that psychosocial stress plays an important part in the development of cardiovascular diseases. Because physical inactivity is associated with less favourable retinal vessel diameter and blood pressure profiles, this study explores whether physical fitness is able to buffer the negative effects of psychosocial stress on retinal vessel diameters and blood pressure in young children. Methods. 325 primary schoolchildren (51% girls, Mage = 7.28 years) took part in this cross-sectional research project. Retinal arteriolar diameters, retinal venular diameters, arteriolar to venular ratio, and systolic and diastolic blood pressure were assessed in all children. Interactions terms between physical fitness (performance in the 20 m shuttle run test) and four indicators of psychosocial stress (parental reports of critical life events, family, peer and school stress) were tested in a series of hierarchical regression analyses. Results. Critical life events and family, peer, and school-related stress were only weakly associated with retinal vessel diameters and blood pressure. No support was found for a stress-buffering effect of physical fitness. Conclusion. More research is needed with different age groups to find out if and from what age physical fitness can protect against arteriolar vessel narrowing and the occurrence of other cardiovascular disease risk factors.

  5. Design of a supercritical water-cooled reactor. Pressure vessel and internals

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Kai

    2008-08-15

    The High Performance Light Water Reactor (HPLWR) is a light water reactor with supercritical steam conditions which has been investigated within the 5th Framework Program of the European Commission. Due to the supercritical pressure of 25 MPa, water, used as moderator and as coolant, flows as a single phase through the core and can be directly fed to the turbine. Using the technology of coal fired power plants with supercritical steam conditions, the heat-up in the core is done in several steps to achieve the targeted high steam outlet temperature of 500.C without exceeding available cladding material limits. Based on a first design of a fuel assembly cluster for a HPLWR with a single pass core, the surrounding internals and the reactor pressure vessel (RPV) are dimensioned for the first time, following the safety standards of the nuclear safety standards commission in Germany. Furthermore, this design is extended to the incorporation of core arrangements with two and three passes. The design of the internals and the RPV are verified using mechanical or, in the case of large thermal deformations, combined mechanical and thermal stress analyses. Additionally, a passive safety component for the feedwater inlet of the RPV of the HPLWR is designed. Its purpose is the reduction of the mass flow rate in case of a LOCA for a feedwater line break until further steps are executed. Starting with a simple vortex diode, several steps are executed to enhance the performance of the diode and adapt it to this application. Then, this first design is further optimized using combined 1D and 3D flow analyses. Parametric studies determine the performance and characteristic for changing mass flow rates for this backflow limiter. (orig.)

  6. International Atomic Energy Agency (IAEA) Coordinated Research Projects on Structural Integrity of Reactor Pressure Vessels

    Energy Technology Data Exchange (ETDEWEB)

    Server, W. L. [ATI Consulting, Pinehurst, NC; Nanstad, Randy K [ORNL

    2009-01-01

    The International Atomic Energy Agency (IAEA) has conducted a series of Coordinated Research Projects (CRPs) that have focused on irradiated reactor pressure vessel (RPV) steel fracture toughness properties and approaches for assuring structural integrity of RPVs throughout operating life. A series of nine CRPs have been sponsored by the IAEA, starting in the early 1970s, focused on neutron radiation effects on RPV steels. The purpose of the CRPs was to develop comparisons and correlations to test the uniformity of irradiated results through coordinated international research studies and data sharing. Consideration of dose rate effects, effects of alloying (nickel, manganese, silicon, etc.) and residual elements (eg., copper and phosphorus), and drop in upper shelf toughness are also important for assessing neutron embrittlement effects. The ultimate use of embrittlement understanding is assuring structural integrity of the RPV under current and future operation and accident conditions. Material fracture toughness is the key ingredient needed for this assessment, and many of the CRPs have focused on measurement and application of irradiated fracture toughness. This paper presents an overview of the progress made since the inception of the CRPs in the early 1970s. The chronology and importance of each CRP have been reviewed and put into context for continued and long-term safe operation of RPVs.

  7. Effects of Surface Roughness, Oxidation, and Temperature on the Emissivity of Reactor Pressure Vessel Alloys

    Energy Technology Data Exchange (ETDEWEB)

    King, J. L. [University of Wisconsin–Madison, Department of Engineering Physics, Madison, Wisconsin; Jo, H. [University of Wisconsin–Madison, Department of Engineering Physics, Madison, Wisconsin; Tirawat, R. [National Renewable Energy Laboratory, Concentrating Solar Power Group, Golden, Colorado; Blomstrand, K. [University of Wisconsin–Madison, Department of Engineering Physics, Madison, Wisconsin; Sridharan, K. [University of Wisconsin–Madison, Department of Engineering Physics, Madison, Wisconsin

    2017-08-31

    Thermal radiation will be an important mode of heat transfer in future high-temperature reactors and in off-normal high-temperature scenarios in present reactors. In this work, spectral directional emissivities of two reactor pressure vessel (RPV) candidate materials were measured at room temperature after exposure to high-temperature air. In the case of SA508 steel, significant increases in emissivity were observed due to oxidation. In the case of Grade 91 steel, only very small increases were observed under the tested conditions. Effects of roughness were also investigated. To study the effects of roughening, unexposed samples of SA508 and Grade 91 steel were roughened via one of either grinding or shot-peening before being measured. Significant increases were observed only in samples having roughness exceeding the roughness expected of RPV surfaces. While the emissivity increases for SA508 from oxidation were indeed significant, the measured emissivity coefficients were below that of values commonly used in heat transfer models. Based on the observed experimental data, recommendations for emissivity inputs for heat transfer simulations are provided.

  8. Effects of thermal annealing and reirradiation on toughness of reactor pressure vessel steels

    Energy Technology Data Exchange (ETDEWEB)

    Nanstad, R.K.; Iskander, S.K.; Sokolov, M.A. [Oak Ridge National Lab., TN (United States)] [and others

    1997-02-01

    One of the options to mitigate the effects of irradiation on reactor pressure vessels (RPV) is to thermally anneal them to restore the toughness properties that have been degraded by neutron irradiation. This paper summarizes recent experimental results from work performed at the Oak Ridge National Laboratory (ORNL) to study the annealing response, or {open_quotes}recovery,{close_quotes} of several irradiated RPV steels; it also includes recent results from both ORNL and the Russian Research Center-Kurchatov Institute (RRC-KI) on a cooperative program of irradiation, annealing and reirradiation of both U.S. and Russian RPV steels. The cooperative program was conducted under the auspices of Working Group 3, U.S./Russia Joint Coordinating Committee for Civilian Nuclear Reactor Safety (JCCCNRS). The materials investigated are an RPV plate and various submerged-arc welds, with tensile, Charpy impact toughness, and fracture toughness results variously determined. Experimental results are compared with applicable prediction guidelines, while observed differences in annealing responses and reirradiation rates are discussed.

  9. Influence of fluence rate on radiation-induced mechanical property changes in reactor pressure vessel steels

    Energy Technology Data Exchange (ETDEWEB)

    Hawthorne, J.R.; Hiser, A.L. (Materials Engineering Associates, Inc., Lanham, MD (USA))

    1990-03-01

    This report describes a set of experiments undertaken using a 2 MW test reactor, the UBR, to qualify the significance of fluence rate to the extent of embrittlement produced in reactor pressure vessel steels at their service temperature. The test materials included two reference plates (A 302-B, A 533-B steel) and two submerged arc weld deposits (Linde 80, Linde 0091 welding fluxes). Charpy-V (C{sub v}), tension and 0.5T-CT compact specimens were employed for notch ductility, strength and fracture toughness (J-R curve) determinations, respectively. Target fluence rates were 8 {times} 10{sup 10}, 6 {times} 10{sup 11} and 9 {times} 10{sup 12} n/cm{sup 2} {minus}s{sup {minus}1}. Specimen fluences ranged from 0.5 to 3.8 {times} 10{sup 19} n/cm{sup 2}, E > 1 MeV. The data describe a fluence-rate effect which may extend to power reactor surveillance as well as test reactor facilities now in use. The dependence of embrittlement sensitivity on fluence rate appears to differ for plate and weld deposit materials. Relatively good agreement in fluence-rate effects definition was observed among the three test methods. 52 figs., 4 tabs.

  10. Nondestructive characterization of embrittlement in reactor pressure vessel steels -- A feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    McHenry, H.I.; Alers, G.A. [National Inst. of Standards and Technology, Boulder, CO (United States). Materials Reliability Div.

    1998-03-01

    The Nuclear Regulatory Commission recently initiated a study by NIST to assess the feasibility of using physical-property measurements for evaluating radiation embrittlement in reactor pressure vessel (RPV) steels. Ultrasonic and magnetic measurements provide the most promising approaches for nondestructive characterization of RPV steels because elastic waves and magnetic fields can sense the microstructural changes that embrittle materials. The microstructural changes of particular interest are copper precipitation hardening, which is the likely cause of radiation embrittlement in RPV steels, and the loss of dislocation mobility that is an attribute of the ductile-to-brittle transition. Measurements were made on a 1% copper steel, ASTM grade A710, in the annealed, peak-aged and overaged conditions, and on an RPV steel, ASTM grade A533B. Nonlinear ultrasonic and micromagnetic techniques were the most promising measures of precipitation hardening. Ultrasonic velocity measurements and the magnetic properties associated with hysteresis-loop measurements were not particularly sensitive to either precipitation hardening or the ductile-to-brittle transition. Measurements of internal friction using trapped ultrasonic resonance modes detected energy losses due to the motion of pinned dislocations; however, the ultrasonic attenuation associated with these measurements was small compared to the attenuation caused by beam spreading that would occur in conventional ultrasonic testing of RPVs.

  11. Microstructure and mechanical characteristics of a laser welded joint in SA508 nuclear pressure vessel steel

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Wei, E-mail: wei.guo-2@manchester.ac.uk [Laser Processing Research Centre, School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Sackville Street, Manchester, M13 9 PL (United Kingdom); Dong, Shiyun [Laser Processing Research Centre, School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Sackville Street, Manchester, M13 9 PL (United Kingdom); Institute of Laser Engineering, Beijing University of Technology, Beijing 100124 (China); Guo, Wei; Francis, John A.; Li, Lin [Laser Processing Research Centre, School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Sackville Street, Manchester, M13 9 PL (United Kingdom)

    2015-02-11

    SA508 steels are typically used in civil nuclear reactors for critical components such as the reactor pressure vessel. Nuclear components are commonly joined using arc welding processes, but with design lives for prospective new build projects exceeding 60 years, new welding technologies are being sought. In this exploratory study, for the first time, autogenous laser welding was carried out on 6 mm thick SA508 Cl.3 steel sheets using a 16 kW fiber laser system operating at a power of 4 kW. The microstructure and mechanical properties (including microhardness, tensile strength, elongation, and Charpy impact toughness) were characterized and the microstructures were compared with those produced through arc welding. A three-dimensional transient model based on a moving volumetric heat source model was also developed to simulate the laser welding thermal cycles in order to estimate the cooling rates included by the process. Preliminary results suggest that the laser welding process can produce welds that are free of macroscopic defects, while the strength and toughness of the laser welded joint in this study matched the values that were obtained for the parent material in the as-welded condition.

  12. Deformation characteristics and sealing performance of metallic-O-ring for a reactor pressure vessel

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Ming Xue; Peng, Xudong; Xie, Linjun; Meng, Xiang Kai [Engineering Research Center of Process Equipment and Its Remanufacture, Ministry of Education, Zhejiang University of Technology, Hangzhou (China); Li, Xing Gen [Ningbo Tiansheng Sealing Packing Co., Ltd., Ningbo (China)

    2016-04-15

    This paper provides a reference to determine the seal performance of metallic O-rings for a reactor pressure vessel (RPV). A nonlinear elastic-plastic model of an O-ring was constructed by the finite element method to analyze its intrinsic properties. It is also validated by experiments on scaled samples. The effects of the compression ratio, the geometrical parameters of the O-ring, and the structure parameters of the groove on the flange are discussed in detail. The results showed that the numerical analysis of the O-ring agrees well with the experimental data, the compression ratio has an important role in the distribution and magnitude of contact stress, and a suitable gap between the sidewall and groove can improve the sealing capability of the O-ring. After the optimization of the sealing structure, some key parameters of the O-ring (i.e., compression ratio, cross-section diameter, wall thickness, sidewall gap) have been recommended for application in megakilowatt class nuclear power plants. Furthermore, air tightness and thermal cycling tests were performed to verify the rationality of the finite element method and to reliably evaluate the sealing performance of a RPV.

  13. Appropriate welding conditions of temper bead weld repair for SQV2A pressure vessel steel

    Energy Technology Data Exchange (ETDEWEB)

    Mizuno, R.; Matsuda, F. [NDE Center, Japan Power Engineering and Inspection Corp. (Japan); Brziak, P. [Welding Research Inst. - Industrial Inst. of Slovak Republic (Slovakia); Lomozik, M. [Inst. of Welding (Poland)

    2004-07-01

    Temper bead welding technique is one of the most important repair welding methods for large structures for which it is difficult to perform the specified post weld heat treatment. In this study, appropriate temper bead welding conditions to improve the characteristics of heat affected zone (HAZ) are studied using pressure vessel steel SQV2A corresponding to ASTM A533 Type B Class 1. Thermal/mechanical simulator is employed to give specimens welding thermal cycles from single to quadruple cycle. Charpy absorbed energy and hardness of simulated CGHAZ by first cycle were degraded as compared with base metal. Improvability of these degradations by subsequent cycles is discussed and appropriate temper bead thermal cycles are clarified. When the peak temperature lower than Ac1 and near Ac1 in the second thermal cycle is applied to CGAHZ by first thermal cycle, the characteristics of CGHAZ improve enough. When the other peak temperatures (that is, higher than Ac1) in the second thermal cycle are applied to the CGHAZ, third or more thermal cycle temper bead process should be applied to improve the properties. Appropriate weld condition ranges are selected based on the above results. The validity of the selected ranges is verified by the temper bead welding test. (orig.)

  14. Rupture Properties of Blood Vessel Walls Measured by Pressure-Imposed Test

    Science.gov (United States)

    Ohashi, Toshiro; Sugita, Syukei; Matsumoto, Takeo; Kumagai, Kiichiro; Akimoto, Hiroji; Tabayashi, Koichi; Sato, Masaaki

    It is expected to be clinically useful to know the mechanical properties of human aortic aneurysms in assessing the potential for aneurysm rupture. For this purpose, a newly designed experimental setup was fabricated to measure the rupture properties of blood vessel walls. A square specimen of porcine thoracic aortas is inflated by air pressure at a rate of 10mmHg/s (≈1.3MPa/s) until rupture occurs. Mean breaking stress was 1.8±0.4 MPa (mean±SD) for the specimens proximal to the heart and 2.3±0.8MPa for the distal specimens, which are not significantly different to those values obtained longitudinally from conventional tensile tests. Moreover, the local breaking stretch ratio in the longitudinal direction was significantly higher at the ruptured site (2.7±0.5) than at the unruptured site (2.2±0.4). This testing system for studying the rupture properties of aortic walls is expected to be applicable to aortic aneurysms. Experimental verification of the present technique for the homogeneous, isotropic material is also presented.

  15. Deformation Characteristics and Sealing Performance of Metallic O-rings for a Reactor Pressure Vessel

    Directory of Open Access Journals (Sweden)

    Mingxue Shen

    2016-04-01

    Full Text Available This paper provides a reference to determine the seal performance of metallic O-rings for a reactor pressure vessel (RPV. A nonlinear elastic-plastic model of an O-ring was constructed by the finite element method to analyze its intrinsic properties. It is also validated by experiments on scaled samples. The effects of the compression ratio, the geometrical parameters of the O-ring, and the structure parameters of the groove on the flange are discussed in detail. The results showed that the numerical analysis of the O-ring agrees well with the experimental data, the compression ratio has an important role in the distribution and magnitude of contact stress, and a suitable gap between the sidewall and groove can improve the sealing capability of the O-ring. After the optimization of the sealing structure, some key parameters of the O-ring (i.e., compression ratio, cross-section diameter, wall thickness, sidewall gap have been recommended for application in megakilowatt class nuclear power plants. Furthermore, air tightness and thermal cycling tests were performed to verify the rationality of the finite element method and to reliably evaluate the sealing performance of a RPV.

  16. The impact of mobile point defect clusters in a kinetic model of pressure vessel embrittlement

    Energy Technology Data Exchange (ETDEWEB)

    Stoller, R.E.

    1998-05-01

    The results of recent molecular dynamics simulations of displacement cascades in iron indicate that small interstitial clusters may have a very low activation energy for migration, and that their migration is 1-dimensional, rather than 3-dimensional. The mobility of these clusters can have a significant impact on the predictions of radiation damage models, particularly at the relatively low temperatures typical of commercial, light water reactor pressure vessels (RPV) and other out-of-core components. A previously-developed kinetic model used to investigate RPV embrittlement has been modified to permit an evaluation of the mobile interstitial clusters. Sink strengths appropriate to both 1- and 3-dimensional motion of the clusters were evaluated. High cluster mobility leads to a reduction in the amount of predicted embrittlement due to interstitial clusters since they are lost to sinks rather than building up in the microstructure. The sensitivity of the predictions to displacement rate also increases. The magnitude of this effect is somewhat reduced if the migration is 1-dimensional since the corresponding sink strengths are lower than those for 3-dimensional diffusion. The cluster mobility can also affect the evolution of copper-rich precipitates in the model since the radiation-enhanced diffusion coefficient increases due to the lower interstitial cluster sink strength. The overall impact of the modifications to the model is discussed in terms of the major irradiation variables and material parameter uncertainties.

  17. A high-pressure vessel for X-ray diffraction experiments for liquids in a wide temperature range

    CERN Document Server

    Hosokawa, S

    2001-01-01

    An internally heated high-pressure vessel was developed for angle-dispersive X-ray scattering experiments on liquids at high-temperatures and high-pressures. It consists of a closed-end Al cylinder and a steel flange. Continuous windows made of Be cover a scattering angle range up to 55 deg. In combination with a single-crystal sapphire cell and a small heating system inside the vessel, we were able to carry out diffraction measurements for liquids in a wide temperature range up to 2000 K at high pressures up to 150 bars. Some of our recent X-ray scattering experiments using synchrotron radiation, such as inelastic scattering, high-energy elastic scattering, and anomalous scattering, are also reported.

  18. Sludge pipe flow pressure drop prediction using composite power ...

    African Journals Online (AJOL)

    2011-09-30

    , pressure gradient, sludge rheology. Notation ... This paper describes the application of a tech- nique presented by Garcia et al. ..... composite power law fric- tion factor correlations for laminar and turbulent gas–liquid flow in.

  19. Dual-pump CARS of Air in a Heated Pressure Vessel up to 55 Bar and 1300 K

    Science.gov (United States)

    Cantu, Luca; Gallo, Emanuela; Cutler, Andrew D.; Danehy, Paul M.

    2014-01-01

    Dual-pump Coherent anti-Stokes Raman scattering (CARS) measurements have been performed in a heated pressure vessel at NASA Langley Research Center. Each measurement, consisting of 500 single shot spectra, was recorded at a fixed location in dry air at various pressures and temperatures, in a range of 0.03-55×10(exp 5) Pa and 300-1373 K, where the temperature was varied using an electric heater. The maximum output power of the electric heater limited the combinations of pressures and temperatures that could be obtained. Charts of CARS signal versus temperature (at constant pressure) and signal versus pressure (at constant temperature) are presented and fit with an empirical model to validate the range of capability of the dual-pump CARS technique; averaged spectra at different conditions of pressure and temperature are also shown.

  20. Irradiation, Annealing, and Reirradiation Effects on American and Russian Reactor Pressure Vessel Steels

    Energy Technology Data Exchange (ETDEWEB)

    Chernobaeva, A.A.; Korolev, Y.N.; Nanstad, R.K.; Nikolaev, Y.A.; Sokolov, M.A.

    1998-06-16

    One of the options to mitigate the effects of irradiation on reactor pressure vessels (RPVs) is to thermally anneal them to restore the toughness properties that have been degraded by neutron irradiation. Even though a postirradiation anneal may be deemed successful, a critical aspect of continued RPV operation is the rate of embrittlement upon reirradiation. There are insufficient data available to allow for verification of available models of reirradiation embrittlement or for the development of a reliable predictive methodology. This is especially true in the case of fracture toughness data. Under the U.S.-Russia Joint Coordinating Committee for Civilian Nuclear Reactor Safety (JCCCNRS), Working Group 3 on Radiation Embrittlement, Structural Integrity, and Life Extension of Reactor Vessels and Supports agreed to conduct a comparative study of annealing and reirradiation effects on RPV steels. The Working Group agreed that each side would irradiate, anneal, reirradiate (if feasible ), and test two materials of the other. Charpy V-notch (CVN) and tensile specimens were included. Oak Ridge National Laboratory (ORNL) conducted such a program (irradiation and annealing, including static fracture toughness) with two weld metals representative of VVER-440 and VVER-1000 RPVs, while the Russian Research Center-Kurchatov Institute (RRC-KI) conducted a program (irradiation, annealing, reirradiation, and reannealing) with Heavy-Section Steel Technology (HSST) Program Plate 02 and Heavy-Section Steel Irradiation (HSSI) Program Weld 73W. The results for each material from each laboratory are compared with those from the other laboratory. The ORNL experiments with the VVER welds included irradiation to about 1 x 10{sup 19} n/cm{sup 2} (>1 MeV), while the RRC-KI experiments with the U.S. materials included irradiations from about 2 to 18 x 10{sup 19} n/cm{sup 2} (>l MeV). In both cases, irradiations were conducted at {approximately}290 C and annealing treatments were conducted

  1. Next Generation Nuclear Plant Reactor Pressure Vessel Materials Research and Development Plan (PLN-2803)

    Energy Technology Data Exchange (ETDEWEB)

    J. K. Wright; R. N. Wright

    2008-04-01

    The U.S. Department of Energy has selected the High Temperature Gas-cooled Reactor design for the Next Generation Nuclear Plant (NGNP) Project. The NGNP will demonstrate the use of nuclear power for electricity and hydrogen production. It will have an outlet gas temperature in the range of 900°C and a plant design service life of 60 years. The reactor design will be a graphite moderated, helium-cooled, prismatic, or pebble-bed reactor and use low-enriched uranium, Tri-Isotopic-coated fuel. The plant size, reactor thermal power, and core configuration will ensure passive decay heat removal without fuel damage or radioactive material releases during accidents. The NGNP Materials Research and Development Program is responsible for performing research and development on likely NGNP materials in support of the NGNP design, licensing, and construction activities. Selection of the technology and design configuration for the NGNP must consider both the cost and risk profiles to ensure that the demonstration plant establishes a sound foundation for future commercial deployments. The NGNP challenge is to achieve a significant advancement in nuclear technology while setting the stage for an economically viable deployment of the new technology in the commercial sector soon after 2020. Studies of potential Reactor Pressure Vessel (RPV) steels have been carried out as part of the pre-conceptual design studies. These design studies generally focus on American Society of Mechanical Engineers (ASME) Code status of the steels, temperature limits, and allowable stresses. Three realistic candidate materials have been identified by this process: conventional light water reactor RPV steels A508/533, 2¼Cr-1Mo in the annealed condition, and modified 9Cr 1Mo ferritic martenistic steel. Based on superior strength and higher temperature limits, the modified 9Cr-1Mo steel has been identified by the majority of design engineers as the preferred choice for the RPV. All of the vendors have

  2. Effect of heterogeneities on the thermoelectric power of pressure vessel steel; Effet des heterogeneites sur le pouvoir thermoelectrique de l'acier de cuve

    Energy Technology Data Exchange (ETDEWEB)

    Simonet, L

    2006-12-15

    In service working conditions, the vessel of the Pressurized Water Reactors (PWR) undergoes an ageing due to irradiation. In order to follow the evolution of the mechanical characteristics of the steel in service, EDF launched a surveillance program which consists to carry out mechanical tests on samples aged in reactor. However, the results of these tests have the disadvantage to be affected by the presence of heterogeneities within the steel. Indeed, because of its manufacturing process, the steel contains segregated areas. Thus, EDF launched Thermoelectric Power Measurements (TEP) on the resilience samples of the surveillance program, to complete the mechanical tests and to help with their interpretation. However, these measurements are today difficult to analyse because they include at the same time the effect of the irradiation and the effect of the metallurgical heterogeneities. The aim of this work consisted in evaluating the effect of the heterogeneities on the TEP of the non-irradiated vessel steel. For that, a numerical model was developed which allows to calculate the TEP of a composite structure. We have shown that the model is pertinent to highlight the effect of the heterogeneities on the TEP of the vessel steel, which is considered like a 'matrix'/'segregation' composite. The model allowed us to put emphasis on the influence of different parameters on the TEP measurement. We have thus showed that the measurements conditions have an important effect on the obtained TEP value (influence of the applied pressure, the position of the sample on the device, the site of the metallurgical heterogeneities,...). (author)

  3. Reactor Pressure Vessel Integrity Assessments with the Grizzly Aging Simulation Code

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, Benjamin; Backman, Marie; Hoffman, William; Chakraborty, Pritam

    2015-08-01

    Grizzly is a simulation tool being developed at Idaho National Laboratory (INL) as part of the US Department of Energy’s Light Water Reactor Sustainability program to provide improved safety assessments of systems, components, and structures in nuclear power plants subjected to age-related degradation. Its goal is to provide an improved scientific basis for decisions surrounding license renewal, which would permit operation of commercial nuclear power plants beyond 60 years. Grizzly is based on INL’s MOOSE framework, which enables multiphysics simulations in a parallel computing environment. It will address a wide variety of aging issues in nuclear power plant systems, components, and structures, modelling both the aging processes and the ability of age-degraded components to perform safely. The reactor pressure vessel (RPV) was chosen as the initial application for Grizzly. Grizzly solves tightly coupled equations of heat conduction and solid mechanics to simulate the global response of the RPV to accident conditions, and uses submodels to represent regions with pre-existing flaws. Domain integrals are used to calculate stress intensity factors on those flaws. A physically based empirical model is used to evaluate material embrittlement, and is used to evaluate whether crack growth would occur. Grizzly can represent the RPV in 2D or 3D, allowing it to evaluate effects that require higher dimensionality models to capture. Work is underway to use lower length scale models of material evolution to inform engineering models of embrittlement. This paper demonstrates an application of Grizzly to RPV failure assessment, and summarizes on-going work.

  4. Effect of tempering temperature on the microstructure and mechanical properties of a reactor pressure vessel steel

    Energy Technology Data Exchange (ETDEWEB)

    Li, C.W.; Han, L.Z.; Luo, X.M.; Liu, Q.D.; Gu, J.F., E-mail: gujf@sjtu.edu.cn

    2016-08-15

    The microstructure and mechanical properties of reactor pressure vessel (RPV) steel were investigated after tempering at different temperatures ranging from 580 to 700 °C for 5 h. With increasing tempering temperature, the impact toughness, which is qualified by Charpy V-notch total absorbed energy, initially increases from 142 to 252 J, and then decreases to 47 J, with a maximum value at 650 °C, while the ultimate tensile strength varies in exactly the opposite direction. Comparing the microstructure and fracture surfaces of different specimens, the variations in toughness and strength with the tempering temperature were generally attributed to the softening of the bainitic ferrite, the agminated Fe{sub 3}C carbides that resulted from decomposition of martensite/austenite (M/A) constituents, the precipitation of Mo{sub 2}C carbides, and the newly formed M/A constituents at the grain boundaries. Finally, the correlation between the impact toughness and the volume fraction of the M/A constituents was established, and the fracture mechanisms for the different tempering conditions are explained. - Highlights: • The dependence of the deterioration of impact toughness on tempering temperature has been analysed. • The instrumented Charpy V-notch impact test has been employed to study the fracture mechanism. • The influence of M/A constituents on different fracture mechanisms based on the hinge model has been demonstrated. • A correlation between the mechanical properties and the amount of M/A constituents has been established.

  5. Models for embrittlement recovery due to annealing of reactor pressure vessel steels

    Energy Technology Data Exchange (ETDEWEB)

    Eason, E.D.; Wright, J.E.; Nelson, E.E. [Modeling and Computing Services, Boulder, CO (United States); Odette, G.R.; Mader, E.V. [California Univ., Santa Barbara, CA (United States)

    1995-05-01

    The reactor pressure vessel (RPV) surrounding the core of a commercial nuclear power plant is subject to embrittlement due to exposure to high energy neutrons. The effects of irradiation embrittlement can be reduced by thermal annealing at temperatures higher than the normal operating conditions. However, a means of quantitatively assessing the effectiveness of annealing for embrittlement recovery is needed. The objective of this work was to analyze the pertinent data on this issue and develop quantitative models for estimating the recovery in 30 ft-lb (41 J) Charpy transition temperature and Charpy upper shelf energy due to annealing. Data were gathered from the Test Reactor Embrittlement Data Base and from various annealing reports. An analysis data base was developed, reviewed for completeness and accuracy, and documented as part of this work. Independent variables considered in the analysis included material chemistries, annealing time and temperature, irradiation time and temperature, fluence, and flux. To identify important variables and functional forms for predicting embrittlement recovery, advanced statistical techniques, including pattern recognition and transformation analysis, were applied together with current understanding of the mechanisms governing embrittlement and recovery. Models were calibrated using multivariable surface-fitting techniques. Several iterations of model calibration, evaluation with respect to mechanistic and statistical considerations, and comparison with the trends in hardness data produced correlation models for estimating Charpy upper shelf energy and transition temperature after irradiation and annealing. This work provides a clear demonstration that (1) microhardness recovery is generally a very good surrogate for shift recovery, and (2) there is a high level of consistency between the observed annealing trends and fundamental models of embrittlement and recovery processes.

  6. Stress analyses for reactor pressure vessels by the example of a product line '69 boiling water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Mkrtchyan, Lilit; Schau, Henry [TUEV SUED Energietechnik GmbH, Mannheim (Germany). Abt. Strukturverhalten; Wolf, Werner; Holzer, Wieland [TUEV SUED Industrie Service GmbH, Muenchen (Germany). Abt. Behaelter und Turbosatz; Wernicke, Robert; Trieglaff, Ralf [TUEV NORD SysTec GmbH und Co. KG, Hamburg (Germany). Abt. Festigkeit und Konstruktion

    2011-08-15

    The reactor pressure vessels (RPV) of boiling water reactors (BWR) belonging to the product line '69 have unusually designed heads. The spherical cap-shaped bottom head of the vessel is welded directly to the support flange of the lower shell course. This unusual construction has led repeatedly to controversial discussions concerning the limits and admissibility of stress intensities arising in the junction of the bottom head to the cylindrical shell. In the present paper, stress analyses for the design conditions are performed with the finite element method in order to determine and categorize the occurring stresses. The procedure of stress classification in accordance with the guidelines of German KTA 3201.2 and Section III of the ASME Code (Subsection NB) is described and subsequently demonstrated by the example of a typical BWR vessel. The accomplished investigations yield allowable stress intensities in the considered area. Additionally, limit load analyses are carried out to verify the obtained results. Complementary studies, performed for a torispherical head, prove that the determined maximum peak stresses in the junction between the bottom head and the cylindrical shell are not unusual also for pressure vessels with regular bottom head constructions. (orig.)

  7. Quantitative measurement of out-of-plan deformation generated at the around defect of pressure vessel using shearography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyoung Suk; Beak, Sang Kyu; Lee, Gun Jung; Chang, Ho Seob [Chosun University, Kwangju (Korea, Republic of); Kang, Myoung Goo [Chosun University RRC, Kwangju (Korea, Republic of); Kim, Sung Sik [Mokpo Science College, Mokpo(Korea, Republic of)

    2006-05-15

    Shearography, one of NDT methods without contact, is able to inspect defects of pipelines and pressure vessels that are used in the industrial machine and nuclear power plants and is used to determine safety, maintenance, and mending. Electronic Speckle Pattern Interferometry(ESPI) is a common method for measuring out-of-plane deformation and in-plane deformation and applied for vibration analysis and strain/stress analysis. However, ESPI is sensitive to environmental disturbance, which provide the limitation of industrial application. On the other hand, Shearography based on shearing interferometer which is insensitive to vibration disturbance can directly measure the first derivative of out-of-plane deformation. In this paper a technique that extract out-of-plane deformation from results of shearography by numerical processing is proposed and measurement results of ESPI and Shearoraphy are compared quantitative to inspect defects of pipelines and pressure vessels.

  8. Reactor moderator, pressure vessel, and heat rejection system of an open-cycle gas core nuclear rocket concept

    Science.gov (United States)

    Taylor, M. F.; Whitmarsh, C. L., Jr.; Sirocky, P. J., Jr.; Iwanczyke, L. C.

    1973-01-01

    A preliminary design study of a conceptual 6000-megawatt open-cycle gas-core nuclear rocket engine system was made. The engine has a thrust of 196,600 newtons (44,200 lb) and a specific impulse of 4400 seconds. The nuclear fuel is uranium-235 and the propellant is hydrogen. Critical fuel mass was calculated for several reactor configurations. Major components of the reactor (reflector, pressure vessel, and waste heat rejection system) were considered conceptually and were sized.

  9. Dismantling of the reactor pressure vessel internals in the NPP Wuergassen; Zerlegung der RDG- Einbauten im KKW Wuergassen

    Energy Technology Data Exchange (ETDEWEB)

    Bruhn, Jan Hendrik [AREVA NP GmbH (Germany)

    2008-07-01

    The reactor pressure vessel internals of the NPP Wuergassen were dismantled and dissected in the time period 19-03-2007 to 21-09-2007 and packaged for final disposal. The total amount was about 18 tons of steel. The dissected was performed using specific water-quartz sand-cutting tools within a settling tank. The dismantling concept intended to cut shape-optimized pieces with respect to space saving packaging. The project included a specific water treatment system.

  10. Self-healing Nanocomposites for Reusable Composite Cryotanks Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Composite cryotanks, or Composite Overwrapped Pressure Vessels (COPVs), offer advantages over currently used aluminum-lithium cryotanks, particularly with respect to...

  11. EFFECT OF 8 WEEKS OF AEROBIC ON BODY COMPOSITION AND BLOOD PRESSURE IN POSTMENOPAUSAL WOMEN

    Directory of Open Access Journals (Sweden)

    Gholamrezai Shahram

    2014-10-01

    Full Text Available Aim: Nowadays increasing blood pressure is the most important risk factor of coronary, cerebral and renal vessel diseases. Epidemiological studies indicate that Physical inactivity adversely affects the blood pressure in postmenopausal women. The purpose of this study was to determine the impact of aerobic on body composition and blood pressure in postmenopausal women. Methods: 20 healthy postmenopausal women with similar age and weight were randomly devided in intervention and control groups. Subjects completed an informed consent form and health history questionnaire. The intervention group was trained in an aerobic exercise program for 8 weeks (3 sessions weekly. Weight, body fat percentage (BF%, body mass index (BMI, waist to hip ratio (WHR, Lean body mass and blood pressure (BP were measured in the beginning and the end of the study for all of the subjects. Data were analyzed by the Paired t-test and independent t- test. Results: The results showed that BF% , WHR, BMI decreased and Lean body mass increased significantly in training group after 8 weeks training (P0.05. Conclusions: It seems that a period of aerobic training for 8 weeks can be effective as a non-pharmacological treatment strategy for improvement some physical fitness and body composition indexes, blood pressure in postmenopausal women.

  12. Preliminary materials selection issues for the next generation nuclear plant reactor pressure vessel.

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.; Majumdar, S.; Shankar, P. S.; Shah, V. N.; Nuclear Engineering Division

    2007-03-21

    In the coming decades, the United States and the entire world will need energy supplies to meet the growing demands due to population increase and increase in consumption due to global industrialization. One of the reactor system concepts, the Very High Temperature Reactor (VHTR), with helium as the coolant, has been identified as uniquely suited for producing hydrogen without consumption of fossil fuels or the emission of greenhouse gases [Generation IV 2002]. The U.S. Department of Energy (DOE) has selected this system for the Next Generation Nuclear Plant (NGNP) Project, to demonstrate emissions-free nuclear-assisted electricity and hydrogen production within the next 15 years. The NGNP reference concepts are helium-cooled, graphite-moderated, thermal neutron spectrum reactors with a design goal outlet helium temperature of {approx}1000 C [MacDonald et al. 2004]. The reactor core could be either a prismatic graphite block type core or a pebble bed core. The use of molten salt coolant, especially for the transfer of heat to hydrogen production, is also being considered. The NGNP is expected to produce both electricity and hydrogen. The process heat for hydrogen production will be transferred to the hydrogen plant through an intermediate heat exchanger (IHX). The basic technology for the NGNP has been established in the former high temperature gas reactor (HTGR) and demonstration plants (DRAGON, Peach Bottom, AVR, Fort St. Vrain, and THTR). In addition, the technologies for the NGNP are being advanced in the Gas Turbine-Modular Helium Reactor (GT-MHR) project, and the South African state utility ESKOM-sponsored project to develop the Pebble Bed Modular Reactor (PBMR). Furthermore, the Japanese HTTR and Chinese HTR-10 test reactors are demonstrating the feasibility of some of the planned components and materials. The proposed high operating temperatures in the VHTR place significant constraints on the choice of material selected for the reactor pressure vessel for

  13. Embedding Piezoresistive Pressure Sensors to Obtain Online Pressure Profiles Inside Fiber Composite Laminates

    Directory of Open Access Journals (Sweden)

    Maryam Kahali Moghaddam

    2015-03-01

    Full Text Available The production of large and complex parts using fiber composite materials is costly due to the frequent formation of voids, porosity and waste products. By embedding different types of sensors and monitoring the process in real time, the amount of wastage can be significantly reduced. This work focuses on developing a knowledge-based method to improve and ensure complete impregnation of the fibers before initiation of the resin cure. Piezoresistive and capacitive pressure sensors were embedded in fiber composite laminates to measure the real-time the pressure values inside the laminate. A change of pressure indicates resin infusion. The sensors were placed in the laminate and the resin was infused by vacuum. The embedded piezoresistive pressure sensors were able to track the vacuum pressure in the fiber composite laminate setup, as well as the arrival of the resin at the sensor. The pressure increase due to closing the resin inlet was also measured. In contrast, the capacitive type of sensor was found to be inappropriate for measuring these quantities. The following study demonstrates real-time monitoring of pressure changes inside the fiber composite laminate, which validate the use of Darcy’s law in porous media to control the resin flow during infusion.

  14. Probabilistic Research of Long Composite Cylinders under Uniform External Pressure

    Science.gov (United States)

    Cai, Baoping; Liu, Yonghong; Huang, Lei; Xue, Haitao; Wang, Jiaxing

    2017-12-01

    This study focuses on the load and resistance factor design (LRFD) procedure for anisotropic long composite cylinders under external pressure. The theoretical analysis is performed, the performance function is presented, the target reliability levels are determined, the statistical characteristics of random variables are researched and the LRFD-based code is calibrated. The results show the LRFD-based design procedure provides explicit and consistent reliability for long composite cylinder, which could lead less conservative design.

  15. In vivo quantification of lymph viscosity and pressure in lymphatic vessels and draining lymph nodes of arthritic joints in mice.

    Science.gov (United States)

    Bouta, Echoe M; Wood, Ronald W; Brown, Edward B; Rahimi, Homaira; Ritchlin, Christopher T; Schwarz, Edward M

    2014-03-15

    Rheumatoid arthritis (RA) is a chronic inflammatory joint disease with episodic flares. In TNF-Tg mice, a model of inflammatory-erosive arthritis, the popliteal lymph node (PLN) enlarges during the pre-arthritic 'expanding' phase, and then 'collapses' with adjacent knee flare associated with the loss of the intrinsic lymphatic pulse. As the mechanisms responsible are unknown, we developed in vivo methods to quantify lymph viscosity and pressure in mice with wild-type (WT), expanding and collapsed PLN. While no differences in viscosity were detected via multiphoton fluorescence recovery after photobleaching (MP-FRAP) of injected FITC-BSA, a 32.6% decrease in lymph speed was observed in vessels afferent to collapsed PLN (P Lymphatic pumping pressure (LPP), measured indirectly by slowly releasing a pressurized cuff occluding indocyanine green (ICG), demonstrated an increase in vessels afferent to expanding PLN versus WT (18.76 ± 2.34 vs. 11.04 ± 1.47 cmH2O; P lymphatic pressure, and provide evidence to support the hypothesis that lymphangiogenesis and lymphatic transport are compensatory mechanisms to prevent synovitis via increased drainage of inflamed joints. Furthermore, the decrease in lymphatic flow and loss of LPP during PLN collapse are consistent with decreased drainage from the joint during arthritic flare, and validate these biomarkers of RA progression and possibly other chronic inflammatory conditions.

  16. Self-repairing composite walls for pressurized space habitats

    Science.gov (United States)

    Dry, Carolyn

    2016-04-01

    A most important factor for human occupied habitats in space is to ensure that the pressurized habitat does not lose pressure catastrophically by the penetration of space debris or micrometeorites through the wall and into the pressurized space. Regenerative self repairing composites used for the space station habitat to prevent loss of pressure was demonstrated in tests The wall sample had ambient pressurized on one side with vacuum on the other, then was punctured all the way through; the pressure reading went from -26 inches of mercury to -26 inches and stayed there indefinitely. There was no loss of pressure! This will be a game changer for space habitat design. This represents a proposed test bed experimental effort on the International Space Station for self repairing regenerative walls of pressurized habitats, supported by significant puncture over vacuum and puncture testing performed to date, which will provide NASA with an innovative new light weight multi-hit superior Astronaut Protective Wall solution for pressurized space habitats.

  17. Effect of consolidation pressure on volumetric composition and stiffness of unidirectional flax fibre composites

    DEFF Research Database (Denmark)

    Aslan, Mustafa; Mehmood, S.; Madsen, Bo

    2013-01-01

    Unidirectional flax/polyethylene terephthalate composites are manufactured by filament winding, followed by compression moulding with low and high consolidation pressure, and with variable flax fibre content. The experimental data of volumetric composition and tensile stiffness are analysed...... with analytical models, and the composite microstructure is assessed by microscopy. The higher consolidation pressure (4.10 vs. 1.67 MPa) leads to composites with a higher maximum attainable fibre volume fraction (0.597 vs. 0.530), which is shown to be well correlated with the compaction behaviour of flax yarn...... diagram showing stiffness of unidirectional flax fibre composites as a function of fibre weight fraction for consolidation pressures in the range 0–10 MPa....

  18. In aged men, central vessel transmural pressure is reduced by brief Valsalva manoeuvre during strength exercise.

    Science.gov (United States)

    Niewiadomski, Wiktor; Pilis, Anna; Strasz, Anna; Laskowska, Dorota; Gąsiorowska, Anna; Pilis, Karol; Cybulski, Gerard

    2014-05-01

    A brief Valsalva manoeuvre, lasting 2-3 s, performed by young healthy men during strength exercise reduces transmural pressure acting on intrathoracic arteries. In this study, we sought to verify this finding in older men. Twenty normotensive, prehypertensive and moderately hypertensive otherwise healthy men 46-69 years old performed knee extensions combined with inspiration or with brief Valsalva manoeuvre performed at 10, 20 and 40 mmHg mouth pressure. Same respiratory manoeuvres were also performed at rest. Non-invasively measured blood pressure, knee angle, respiratory airflow and mouth pressure were continuously registered. In comparison to inspiration, estimated transmural pressure acting on thoracic arteries changed slightly and insignificantly during brief Valsalva manoeuvre at 10 and 20 mmHg mouth pressure. At 40 mmHg mouth pressure, transmural pressure declined at rest (-8·8 ± 11·4 mmHg) and during knee extension (-12·1 ± 11·9 mmHg). This decline ensued, as peak systolic pressure increase caused by this manoeuvre, was distinctly transmural pressure decline, depended mainly on intrathoracic pressure developed during brief Valsalva manoeuvre. Resting blood pressure did not influence the effect of brief Valsalva manoeuvre on transmural pressure. © 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  19. 10 CFR 50.66 - Requirements for thermal annealing of the reactor pressure vessel.

    Science.gov (United States)

    2010-01-01

    ... reactors where neutron radiation has reduced the fracture toughness of the reactor vessel materials, a... operation using appropriate test data. (iii) The methods, including heat source, instrumentation and... monitoring, inspections, and tests proposed to demonstrate that the limitations on temperatures, times and...

  20. Effect of simulated pulpal pressure on composite bond strength to ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-10-19

    Oct 19, 2009 ... adhesive system was used. Key words: Bond strength, laser treatment, pulpal pressure, resin composite. INTRODUCTION. Adhesive techniques have expanded the range of possi- bilities for operative and esthetic dentistry (Kato and. Nakabayashi, 1998). Bonding to enamel is a relatively simple procedure ...

  1. Impact of radiation embrittlement on integrity of pressure vessel supports for two PWR plants

    Energy Technology Data Exchange (ETDEWEB)

    Cheverton, R.D.; Pennell, W.E.; Robinson, G.C.; Nanstad, R.K.

    1989-01-01

    Recent data from the HFIR vessel surveillance program indicate a substantial radiation embrittlement rate effect at low irradiation temperatures (/approximately/120/degree/F) for A212-B, A350-LF3, A105-II, and corresponding welds. PWR vessel supports are fabricated of similar materials and are subjected to the same low temperatures and fast neutron fluxes (10/sup 8/ to 10/sup 9/ neutrons/cm/sup 2//center dot/s, E > 1.0 MeV) as those in the HFIR vessel. Thus, the embrittlement rate of these structures may be greater than previously anticipated. A study sponsored by the NRC is under way at ORNL to determine the impact of the rate effect on PWR vessel-support life expectancy. The scope includes the interpretation and application of the HFIR data, a survey of all light-water-reactor vessel support designs, and a structural and fracture-mechanics analysis of the supports for two specific PWR plants of particular interest with regard to a potential for support failure as a result of propagation of flaws. Calculations performed thus far indicate best-estimate critical flaw sizes, corresponding to 32 EFPY, of /approximately/0.2 in. for one plant and /approximately/0.4 in. for the other. These flaw sizes are small enough to be of concern. However, it appears that low-cycle fatigue is not a viable mechanism for creation of flaws of this size, and thus, presumably, such flaws would have to exist at the time of fabrication. 59 refs., 128 figs., 49 tabs.

  2. Evaluation of J-groove weld residual stress and crack growth rate of PWSCC in reactor pressure vessel closure head

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Seung Hyuk; Ryu, Tae Young; Park, Seung Hyun; Won, Min Gu; Kang, Seok Jun; Kim, Moon Ki; Choi, Jae Boong [Sungkyunkwan University, Suwon (Korea, Republic of); Lee, Kyoung Soo; Lee, Sung Ho [Korea Hydro and Nuclear Power, Daejeon (Korea, Republic of)

    2015-03-15

    Over the last decade, primary water stress corrosion cracking (PWSCC) has been frequently found in pressurized water reactor (PWR) applications. Especially, PWSCC has occurred in long-term operated PWRs. As this phenomenon leads to serious accidents, we must be beforehand with the anticipated problems. A typical PWR consists of J-groove welded components such as reactor pressure vessel closure head and nozzles. Reactor pressure vessel closure head is made of SA508 and it is covered by cladding. Alloy 600 is used for nozzles. And J-groove weld is conducted with alloy 82/182. Different material properties of these metals lead to residual stress and PWSCC consequentially. In this study, J-groove weld residual stress was investigated by a three-dimensional finite element analysis with an actual asymmetric J-groove weld model and process of construction. Also crack growth rate of PWSCC was evaluated from cracks applied on the penetration nozzles. Based on these two values, one cannot only improve the structural integrity of PWR, but also explain PWSCC behavior such that high residual stress at the J-groove weld area causes crack initiation and propagation through the surface of nozzles. In addition, crack behavior was predicted at the various points around the nozzle.

  3. Probabilistic Fracture Mechanics Analysis of Boling Water Reactor Vessel for Cool-Down and Low Temperature Over-Pressurization Transients

    Directory of Open Access Journals (Sweden)

    Jeong Soon Park

    2016-04-01

    Full Text Available The failure probabilities of the reactor pressure vessel (RPV for low temperature over-pressurization (LTOP and cool-down transients are calculated in this study. For the cool-down transient, a pressure–temperature limit curve is generated in accordance with Section XI, Appendix G of the American Society of Mechanical Engineers (ASME code, from which safety margin factors are deliberately removed for the probabilistic fracture mechanics analysis. Then, sensitivity analyses are conducted to understand the effects of some input parameters. For the LTOP transient, the failure of the RPV mostly occurs during the period of the abrupt pressure rise. For the cool-down transient, the decrease of the fracture toughness with temperature and time plays a main role in RPV failure at the end of the cool-down process. As expected, the failure probability increases with increasing fluence, Cu and Ni contents, and initial reference temperature-nil ductility transition (RTNDT. The effect of warm prestressing on the vessel failure probability for LTOP is not significant because most of the failures happen before the stress intensity factor reaches the peak value while its effect reduces the failure probability by more than one order of magnitude for the cool-down transient.

  4. Improved epoxy resin for constructing cryogenic filament-wound pressure vessels

    Science.gov (United States)

    Molho, R.; Soffer, L. M.

    1971-01-01

    Mechanical properties of new resin at cryogenic temperatures are substantially improved over similar composite structures utilizing conventional resins, while properties at ambient temperature are identical to conventional resin composites.

  5. Prediction and Monitoring Systems of Creep-Fracture Behavior of 9Cr-1Mo Steels for Teactor Pressure Vessels

    Energy Technology Data Exchange (ETDEWEB)

    Potirniche, Gabriel [Univ. of Idaho, Moscow, ID (United States); Barlow, Fred D. [Univ. of Idaho, Moscow, ID (United States); Charit, Indrajit [Univ. of Idaho, Moscow, ID (United States); Rink, Karl [Univ. of Idaho, Moscow, ID (United States)

    2013-11-26

    A recent workshop on next-generation nuclear plant (NGNP) topics underscored the need for research studies on the creep fracture behavior of two materials under consideration for reactor pressure vessel (RPV) applications: 9Cr-1Mo and SA-5XX steels. This research project will provide a fundamental understanding of creep fracture behavior of modified 9Cr-1Mo steel welds for through modeling and experimentation and will recommend a design for an RPV structural health monitoring system. Following are the specific objectives of this research project: Characterize metallurgical degradation in welded modified 9Cr-1Mo steel resulting from aging processes and creep service conditions; Perform creep tests and characterize the mechanisms of creep fracture process; Quantify how the microstructure degradation controls the creep strength of welded steel specimens; Perform finite element (FE) simulations using polycrystal plasticity to understand how grain texture affects the creep fracture properties of welds; Develop a microstructure-based creep fracture model to estimate RPVs service life; Manufacture small, prototypic, cylindrical pressure vessels, subject them to degradation by aging, and measure their leak rates; Simulate damage evolution in creep specimens by FE analyses; Develop a model that correlates gas leak rates from welded pressure vessels with the amount of microstructural damage; Perform large-scale FE simulations with a realistic microstructure to evaluate RPV performance at elevated temperatures and creep strength; Develop a fracture model for the structural integrity of RPVs subjected to creep loads; and Develop a plan for a non-destructive structural health monitoring technique and damage detection device for RPVs.

  6. The effect of microstructural changes on magnetic barkhausen noise in Mn-Mo-Ni pressure vessel steel

    CERN Document Server

    Jeong, H T; Hong, J H; Ahn, Y S; Kim, G M

    1999-01-01

    The effect of microstructural changes on magnetic Barkhausen noise (BN) has been investigated in Mn-Mo-Ni pressure-vessel steel with various microstructures. The BN energy was strongly influenced by the microstructural features, such as the dislocation density, the residual stress, and the carbide morphology. The measured differences in BN signals are discussed on the basis of the domain wall dynamics associated with the microstructural states. The microstructures were observed by using atomic force microscopy(AFM), and the AFM results compared with the scanning electron microscopy observations.

  7. The passive biomechanics of human pelvic collecting lymphatic vessels.

    Science.gov (United States)

    Athanasiou, Dimitrios; Edgar, Lowell T; Jafarnejad, Mohammad; Nixon, Katherine; Duarte, Delfim; Hawkins, Edwin D; Jamalian, Samira; Cunnea, Paula; Lo Celso, Cristina; Kobayashi, Shunichi; Fotopoulou, Christina; Moore, James E

    2017-01-01

    The lymphatic system has a major significance in the metastatic pathways in women's cancers. Lymphatic pumping depends on both extrinsic and intrinsic mechanisms, and the mechanical behavior of lymphatic vessels regulates the function of the system. However, data on the mechanical properties and function of human lymphatics are lacking. Our aim is to characterize, for the first time, the passive biomechanical behavior of human collecting lymphatic vessels removed at pelvic lymph node dissection during primary debulking surgeries for epithelial ovarian cancer. Isolated vessels were cannulated and then pressurized at varying levels of applied axial stretch in a calcium-free Krebs buffer. Pressurized vessels were then imaged using multi-photon microscopy for collagen-elastin structural composition and fiber orientation. Both pressure-diameter and force-elongation responses were highly nonlinear, and axial stretching of the vessel served to decrease diameter at constant pressure. Pressure-diameter behavior for the human vessels is very similar to data from rat mesenteric vessels, though the human vessels were approximately 10× larger than those from rats. Multiphoton microscopy revealed the vessels to be composed of an inner layer of elastin with an outer layer of aligned collagen fibers. This is the first study that successfully described the passive biomechanical response and composition of human lymphatic vessels in patients with ovarian cancer. Future work should expand on this knowledge base with investigations of vessels from other anatomical locations, contractile behavior, and the implications on metastatic cell transport.

  8. Validation of 3D Code KATRIN For Fast Neutron Fluence Calculation of VVER-1000 Reactor Pressure Vessel by Ex-Vessel Measurements and Surveillance Specimens Results

    Directory of Open Access Journals (Sweden)

    Dzhalandinov A.

    2016-01-01

    Full Text Available Usually the synthesis of two-dimensional and one-dimensional discrete ordinate calculations is used to evaluate neutron fluence on VVER-1000 reactor pressure vessel (RPV for prognosis of radiation embrittlement. But there are some cases when this approach is not applicable. For example the latest projects of VVER-1000 have upgraded surveillance program. Containers with surveillance specimens are located on the inner surface of RPV with fast neutron flux maximum. Therefore, the synthesis approach is not suitable enough for calculation of local disturbance of neutron field in RPV inner surface behind the surveillance specimens because of their complicated and heterogeneous structure. In some cases the VVER-1000 core loading consists of fuel assemblies with different fuel height and the applicability of synthesis approach is also ambiguous for these fuel cycles. Also, the synthesis approach is not enough correct for the neutron fluence estimation at the RPV area above core top. Because of these reasons only the 3D neutron transport codes seem to be satisfactory for calculation of neutron fluence on the VVER-1000 RPV. The direct 3D calculations are also recommended by modern regulations.

  9. Status and Perspectives of Nuclear Reactor Pressure Vessel Life Extension up to 60 Years Operation in Belgium

    Energy Technology Data Exchange (ETDEWEB)

    Lucon, E.; Chaouadi, R.; Scibetta, M.; Van Walle, E.

    2009-09-15

    The scope of this report involves a safety evaluation of the reactor pressure vessel (RPV) against neutron embrittlement, in the most severely irradiation region (belt line) and in the event of a pressurized thermal shock. The irreplaceable RPV is considered to be the most critical component for lifetime considerations of the nuclear power plant. However, an application for operation extension will also depend upon a number of additional considerations, including the technical assessment of other plant components, as well as non-technical arguments (e.g. political, environmental, economical, strategical that are outside the scope this report. In the hypothesis of a request for operation extension, it is the responsibility of the utilities to provide the safety authorities with an exhaustive dossier demonstrating that safe extended operation is guaranteed. The role of the safety authorities is to critically evaluate the safety dossier for eventually granting the operation extension.

  10. Numerical Determination and Experimental Validation of a Technological Specimen Representative of High-Pressure Hydrogen Storage Vessels

    Science.gov (United States)

    Gentilleau, B.; Touchard, F.; Grandidier, J.-C.; Mellier, D.

    2015-09-01

    A technological specimen representative of type IV high-pressure hydrogen storage vessels is developed. An analytical model is used to compute fiber orientations in the specimen in order to be as representative as possible of the stress level reached in a tank during pressurization. A three-dimensional finite-element model is used to determine the best stacking sequence with these fiber orientations. A validation is done by performing tests with digital image correlation in order to measure displacements on the lateral side of the specimen. A comparison between the calculated and experimentally found strain fields is made. The results obtained highlight the influence of stacking sequence on the development of damage and the difficulty arising in designing representative specimens.

  11. Characteristics of Modified 9Cr-1Mo Steel for Reactor Pressure Vessel of Very High Temperature Gas Cooled Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Ho; Ryu, W. S.; Han, Chang Hee; Yoon, J. H.; Chang, Jong Hwa

    2004-11-15

    Many researches and developments have been progressed for the construction of VHTR by 2020 in Korea. Modified 9Cr-1Mo steel has been receiving attention for the application to the reactor pressure vessel material of VHTR. We collected and analyzed the research data for modified 9Cr-1Mo steel in order to understand the characteristics of modified 9Cr-1Mo steel. The modified 9Cr-1Mo steel is a modified alloy system similar to conventional 9Cr-1Mo grade ferritic steel. Modifications include additions of vanadium, niobium, and nitrogen, as well as lower carbon content. In this report, we summarized the change of microstructure and mechanical properties after tempering, thermal aging, and irradiation. Modified 9Cr-1Mo steel has high strength and thermal conductivity, low thermal expansion, and good resistance to corrosion. But the irradiation embrittlement behavior of modified 9Cr-1Mo steel should be evaluated and the evaluation methodology also should be developed. At the same time, the characteristics of weldment which is the weak part in pressure vessel should be evaluated.

  12. Disclosure of the oscillations in kinetics of the reactor pressure vessel steel damage at fast neutron intensity decreasing

    Science.gov (United States)

    Krasikov, E.; Nikolaenko, V.

    2017-01-01

    Fast neutron intensity influence on reactor materials radiation damage is a critically important question in the problem of the correct use of the accelerated irradiation tests data for substantiation of the materials workability in real irradiation conditions that is low neutron intensity. Investigations of the fast neutron intensity (flux) influence on radiation damage and experimental data scattering reveal the existence of non-monotonous sections in kinetics of the reactor pressure vessels (RPV) steel damage. Discovery of the oscillations as indicator of the self-organization processes presence give reasons for new ways searching on reactor pressure vessel (RPV) steel radiation stability increasing and attempt of the self-restoring metal elaboration. Revealing of the wavelike process in the form of non monotonous parts of the kinetics of radiation embrittlement testifies that periodic transformation of the structure take place. This fact actualizes the problem of more precise definition of the RPV materials radiation embrittlement mechanisms and gives reasons for search of the ways to manage the radiation stability (nanostructuring and so on to stimulate the radiation defects annihilation), development of the means for creating of more stableness self recovering smart materials.

  13. The influence of selected containment structures on debris dispersal and transport following high pressure melt ejection from the reactor vessel

    Energy Technology Data Exchange (ETDEWEB)

    Pilch, M.; Tarbell, W.W.; Brockmann, J.E.

    1988-09-01

    High pressure expulsion of molten core debris from the reactor pressure vessel may result in dispersal of the debris from the reactor cavity. In most plants, the cavity exits into the containment such that the debris impinges on structures. Retention of the debris on the structures may affect the further transport of the debris throughout the containment. Two tests were done with scaled structural shapes placed at the exit of 1:10 linear scale models of the Zion cavity. The results show that the debris does not adhere significantly to structures. The lack of retention is attributed to splashing from the surface and reentrainment in the gas flowing over the surface. These processes are shown to be applicable to reactor scale. A third experiment was done to simulate the annular gap between the reactor vessel and cavity wall. Debris collection showed that the fraction of debris exiting through the gap was greater than the gap-to-total flow area ratio. Film records indicate that dispersal was primarily by entrainment of the molten debris in the cavity. 29 refs., 36 figs., 11 tabs.

  14. Next Generation Nuclear Plant Reactor Pressure Vessel Materials Research and Development Plan (PLN-2803)

    Energy Technology Data Exchange (ETDEWEB)

    J. K. Wright; R. N. Wright

    2010-07-01

    The U.S. Department of Energy (DOE) has selected the High-Temperature Gas-cooled Reactor (HTGR) design for the Next Generation Nuclear Plant (NGNP) Project. The NGNP will demonstrate the use of nuclear power for electricity and hydrogen production, with an outlet gas temperature in the range of 750°C, and a design service life of 60 years. The reactor design will be a graphite-moderated, helium-cooled, prismatic, or pebble bed reactor and use low-enriched uranium, Tri-Isotopic (TRISO)-coated fuel. The plant size, reactor thermal power, and core configuration will ensure passive decay heat removal without fuel damage or radioactive material releases during accidents. Selection of the technology and design configuration for the NGNP must consider both the cost and risk profiles to ensure that the demonstration plant establishes a sound foundation for future commercial deployments. The NGNP challenge is to achieve a significant advancement in nuclear technology while setting the stage for an economically viable deployment of the new technology in the commercial sector soon after 2020. This technology development plan details the additional research and development (R&D) required to design and license the NGNP RPV, assuming that A 508/A 533 is the material of construction. The majority of additional information that is required is related to long-term aging behavior at NGNP vessel temperatures, which are somewhat above those commonly encountered in the existing database from LWR experience. Additional data are also required for the anticipated NGNP environment. An assessment of required R&D for a Grade 91 vessel has been retained from the first revision of the R&D plan in Appendix B in somewhat less detail. Considerably more development is required for this steel compared to A 508/A 533 including additional irradiation testing for expected NGNP operating temperatures, high-temperature mechanical properties, and extensive studies of long-term microstructural stability.

  15. A high-throughput platform for low-volume high-temperature/pressure sealed vessel solvent extractions

    Energy Technology Data Exchange (ETDEWEB)

    Damm, Markus [Christian Doppler Laboratory for Microwave Chemistry (CDLMC) and Institute of Chemistry, Karl-Franzens-University Graz, Heinrichstrasse 28, A-8010 Graz (Austria); Kappe, C. Oliver, E-mail: oliver.kappe@uni-graz.at [Christian Doppler Laboratory for Microwave Chemistry (CDLMC) and Institute of Chemistry, Karl-Franzens-University Graz, Heinrichstrasse 28, A-8010 Graz (Austria)

    2011-11-30

    Highlights: Black-Right-Pointing-Pointer Parallel low-volume coffee extractions in sealed-vessel HPLC/GC vials. Black-Right-Pointing-Pointer Extractions are performed at high temperatures and pressures (200 Degree-Sign C/20 bar). Black-Right-Pointing-Pointer Rapid caffeine determination from the liquid phase. Black-Right-Pointing-Pointer Headspace analysis of volatiles using solid-phase microextraction (SPME). - Abstract: A high-throughput platform for performing parallel solvent extractions in sealed HPLC/GC vials inside a microwave reactor is described. The system consist of a strongly microwave-absorbing silicon carbide plate with 20 cylindrical wells of appropriate dimensions to be fitted with standard HPLC/GC autosampler vials serving as extraction vessels. Due to the possibility of heating up to four heating platforms simultaneously (80 vials), efficient parallel analytical-scale solvent extractions can be performed using volumes of 0.5-1.5 mL at a maximum temperature/pressure limit of 200 Degree-Sign C/20 bar. Since the extraction and subsequent analysis by either gas chromatography or liquid chromatography coupled with mass detection (GC-MS or LC-MS) is performed directly from the autosampler vial, errors caused by sample transfer can be minimized. The platform was evaluated for the extraction and quantification of caffeine from commercial coffee powders assessing different solvent types, extraction temperatures and times. For example, 141 {+-} 11 {mu}g caffeine (5 mg coffee powder) were extracted during a single extraction cycle using methanol as extraction solvent, whereas only 90 {+-} 11 were obtained performing the extraction in methylene chloride, applying the same reaction conditions (90 Degree-Sign C, 10 min). In multiple extraction experiments a total of {approx}150 {mu}g caffeine was extracted from 5 mg commercial coffee powder. In addition to the quantitative caffeine determination, a comparative qualitative analysis of the liquid phase coffee

  16. Calcium channel blockade prevents pressure-dependent inward remodeling in isolated subendocardial resistance vessels

    NARCIS (Netherlands)

    O. Sorop (Oana); E.N.T.P. Bakker (Erik ); A. Pistea (Adrian); J.A. Spaan (Jos Ae); E. VanBavel (Ed)

    2006-01-01

    textabstractThe capacity for myocardial perfusion depends on the structure of the coronary microvascular bed. Coronary microvessels may adapt their structure to various stimuli. We tested whether the local pressure profile affects tone and remodeling of porcine coronary microvessels. Subendocardial

  17. Fabrication and characterization of magnetic composite membrane pressure sensor

    KAUST Repository

    Khan, Mohammed Asadullah

    2016-04-20

    This paper describes a magnetic field powered pressure sensor, which comprises a coil array and a magnetic composite membrane. The composite membrane is made by embedding a ribbon of the amorphous soft magnetic alloy Vitrovac®, in a 17 mm x 25 mm x 1.5 mm Polydimethylsiloxane (PDMS) layer. PDMS is chosen for its low Young\\'s modulus and the amorphous alloy for its high permeability. The membrane is suspended 1.5 mm above a 17x19 array of microfabricated planar coils. The coils are fabricated by patterning a 620 nm thick gold layer. Each coil occupies an area of 36000 μm2 and consists of 14 turns. The sensor is tested by subjecting it to pressure and simultaneously exciting it by a 24 A/m, 100 kHz magnetic field. A pressure change from 0 kPa to 5.1 kPa, results in a 5400 ppm change in the voltage output.

  18. The Effect of Variable Composition Equilibrium Thermochemistry in Constant Breech Pressure (CBP) Gun Simulations

    Science.gov (United States)

    2014-01-01

    The Effect of Variable Composition Equilibrium Thermochemistry in Constant Breech Pressure (CBP) Gun Simulations by Anthony J. Kotlar...Effect of Variable Composition Equilibrium Thermochemistry in Constant Breech Pressure (CBP) Gun Simulations Anthony J. Kotlar Weapons and...May 1995 4. TITLE AND SUBTITLE The Effect of Variable Composition Equilibrium Thermochemistry in Constant Breech Pressure (CBP) Gun Simulations 5a

  19. Shape optimization on the nozzle of a spherical pressure vessel using the ranked bidirectional evolutionary structural optimization

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young Shin; Ryu, Chung Hyun [Chungnam National Univ., Taejon (Korea, Republic of)

    2001-07-01

    To reduce stress concentration around the intersection between a spherical pressure vessel and a cylindrical nozzle under various load conditions using less material, the optimization for the distribution of reinforcement has researched. The Ranked Bidirectional Evolutionary Structural Optimization(R-BESO) method is developed recently, which adds elements based on a rank, and the performance indicator which can estimate a fully stressed model. The R-BESO method can obtain the optimum design using less iteration number than iteration number of the BESO. In this paper, the optimized intersection shape is sought using R-BESO method for a flush and a protruding nozzle. The considered load cases are a radial compression, torque and shear force.

  20. Stress categorization in nozzle to pressure vessel connections finite elements models; Categorizacao de tensoes em modelos de elementos finitos de conexoes bocal-vaso de pressao

    Energy Technology Data Exchange (ETDEWEB)

    Albuquerque, Levi Barcelos de

    1999-07-01

    The ASME Boiler and Pressure Vessel Code, Section III , is the most important code for nuclear pressure vessels design. Its design criteria were developed to preclude the various pressure vessel failure modes throughout the so-called 'Design by Analysis', some of them by imposing stress limits. Thus, failure modes such as plastic collapse, excessive plastic deformation and incremental plastic deformation under cyclic loading (ratchetting) may be avoided by limiting the so-called primary and secondary stresses. At the time 'Design by Analysis' was developed (early 60's) the main tool for pressure vessel design was the shell discontinuity analysis, in which the results were given in membrane and bending stress distributions along shell sections. From that time, the Finite Element Method (FEM) has had a growing use in pressure vessels design. In this case, the stress results are neither normally separated in membrane and bending stress nor classified in primary and secondary stresses. This process of stress separation and classification in Finite Element (FE) results is what is called stress categorization. In order to perform the stress categorization to check results from FE models against the ASME Code stress limits, mainly from 3D solid FE models, several research works have been conducted. This work is included in this effort. First, a description of the ASME Code design criteria is presented. After that, a brief description of how the FEM can be used in pressure vessel design is showed. Several studies found in the literature on stress categorization for pressure vessel FE models are reviewed and commented. Then, the analyses done in this work are presented in which some typical nozzle to pressure vessel connections subjected to internal pressure and concentrated loads were modeled with solid finite elements. The results from linear elastic and limit load analyses are compared to each other and also with the results obtained by formulae

  1. Assessment of Negligible Creep, Off-Normal Welding and Heat Treatment of Gr91 Steel for Nuclear Reactor Pressure Vessel Application

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Weiju [ORNL; Terry, Totemeier [Idaho National Laboratory (INL)

    2006-10-01

    Two different topics of Grade 91 steel are investigated for Gen IV nuclear reactor pressure vessel application. On the first topic, negligible creep of Grade 91 is investigated with the motivation to design the reactor pressure vessel in negligible creep regime and eliminate costly surveillance programs during the reactor operation. Available negligible creep criteria and creep strain laws are reviewed, and new data needs are evaluated. It is concluded that modifications of the existing criteria and laws, together with their associated parameters, are needed before they can be reliably applied to Grade 91 for negligible creep prediction and reactor pressure vessel design. On the second topic, effects of off-normal welding and heat treatment on creep behavior of Grade 91 are studied with the motivation to better define the control over the parameters in welding and heat treatment procedures. The study is focused on off-normal austenitizing temperatures and improper cooling after welding but prior to post-weld heat treatment.

  2. Application of atmospheric pressure plasma in polymer and composite adhesion

    Science.gov (United States)

    Yu, Hang

    An atmospheric pressure helium and oxygen plasma was used to investigate surface activation and bonding in polymer composites. This device was operated by passing 1.0-3.0 vol% of oxygen in helium through a pair of parallel plate metal electrodes powered by 13.56 or 27.12 MHz radio frequency power. The gases were partially ionized between the capacitors where plasma was generated. The reactive species in the plasma were carried downstream by the gas flow to treat the substrate surface. The temperature of the plasm gas reaching the surface of the substrate did not exceed 150 °C, which makes it suitable for polymer processing. The reactive species in the plasma downstream includes ~ 1016-1017 cm-3 atomic oxygen, ~ 1015 cm-3 ozone molecule, and ~ 10 16 cm-3 metastable oxygen molecule (O2 1Deltag). The substrates were treated at 2-5 mm distance from the exit of the plasma. Surface properties of the substrates were characterized using water contact angle (WCA), atomic force microscopy (AFM), infrared spectroscopy (IR), and X-ray photoelectron spectroscopy (XPS). Subsequently, the plasma treated samples were bonded adhesively or fabricated into composites. The increase in mechanical strength was correlated to changes in the material composition and structure after plasma treatment. The work presented hereafter establishes atmospheric pressure plasma as an effective method to activate and to clean the surfaces of polymers and composites for bonding. This application can be further expanded to the activation of carbon fibers for better fiber-resin interactions during the fabrication of composites. Treating electronic grade FR-4 and polyimide with the He/O2 plasma for a few seconds changed the substrate surface from hydrophobic to hydrophilic, which allowed complete wetting of the surface by epoxy in underfill applications. Characterization of the surface by X-ray photoelectron spectroscopy shows formation of oxygenated functional groups, including hydroxyl, carbonyl, and

  3. NESC Review of the 8-Foot High Temperature Tunnel (HTT) Oxygen Storage Pressure Vessel Inspection Requirements

    Science.gov (United States)

    Gilbert, Michael; Raju, Ivatury; Piascik, Robert; Cameron, Kenneth; Kirsch, Michael; Hoffman, Eric; Murthy, Pappu; Hopson, George; Greulich, Owen; Frazier, Wayne

    2009-01-01

    The 8-Foot HTT (refer to Figure 4.0-1) is used to conduct tests of air-breathing hypersonic propulsion systems at Mach numbers 4, 5, and 7. Methane, Air, and LOX are mixed and burned in a combustor to produce test gas stream containing 21 percent by volume oxygen. The NESC was requested by the NASA LaRC Executive Safety Council to review the rationale for a proposed change to the recertification requirements, specifically the internal inspection requirements, of the 8-Foot HTT LOX Run Tank and LOX Storage Tank. The Run Tank is an 8,000 gallon cryogenic tank used to provide LOX to the tunnel during operations, and is pressured during the tunnel run to 2,250 pounds per square inch gage (psig). The Storage Tank is a 25,000 gallon cryogenic tank used to store LOX at slightly above atmospheric pressure as a external shell, with space between the shells maintained under vacuum conditions.

  4. Thermal stresses in a spherical pressure vessel having temperature-dependent, transversely isotropic, elastic properties

    Science.gov (United States)

    Tauchert, T. R.

    1976-01-01

    Rayleigh-Ritz and modified Rayleigh-Ritz procedures are used to construct approximate solutions for the response of a thick-walled sphere to uniform pressure loads and an arbitrary radial temperature distribution. The thermoelastic properties of the sphere are assumed to be transversely isotropic and nonhomogeneous; variations in the elastic stiffness and thermal expansion coefficients are taken to be an arbitrary function of the radial coordinate and temperature. Numerical examples are presented which illustrate the effect of the temperature-dependence upon the thermal stress field. A comparison of the approximate solutions with a finite element analysis indicates that Ritz methods offer a simple, efficient, and relatively accurate approach to the problem.

  5. Thermal–mechanical stress analysis of pressurized water reactor pressure vessel with/without a preexisting crack under grid load following conditions

    Energy Technology Data Exchange (ETDEWEB)

    Mohanty, Subhasish, E-mail: smohanty@anl.gov; Soppet, William K.; Majumdar, Saurin; Natesan, Krishnamurti

    2016-12-15

    Highlights: • Use of intermittent renewable-energy source in power grid is becoming a trend. • Gird load-following can leads to variable power demand from Nuclear power plant. • Reactor components can be stressed differently under gird load-following mode. • Estimation of stress–strain state under grid load-following condition is essential. - Abstract: In this paper, we present thermal–mechanical stress analysis of a pressurized water reactor pressure vessel and its hot-leg and cold-leg nozzles. Results are presented from thermal and thermal–mechanical stress analysis under reactor heat-up, cool-down, and grid load-following conditions. Analysis results are given with and without the presence of preexisting crack in the reactor nozzle (axial crack in hot leg nozzle). From the model results it is found that the stress–strain states are significantly higher in case of presence of crack than without crack. The stress–strain state under grid load following condition are more realistic compared to the stress–strain state estimated assuming simplified transients.

  6. HTGR Base Technology Program. Task 2: concrete properties in nuclear environment. A review of concrete material systems for application to prestressed concrete pressure vessels

    Energy Technology Data Exchange (ETDEWEB)

    Naus, D.J.

    1981-05-01

    Prestressed concrete pressure vessels (PCPVs) are designed to serve as primary pressure containment structures. The safety of these structures depends on a correct assessment of the loadings and proper design of the vessels to accept these loadings. Proper vessel design requires a knowledge of the component (material) properties. Because concrete is one of the primary constituents of PCPVs, knowledge of its behavior is required to produce optimum PCPV designs. Concrete material systems are reviewed with respect to constituents, mix design, placing, curing, and strength evaluations, and typical concrete property data are presented. Effects of extreme loadings (elevated temperature, multiaxial, irradiation) on concrete behavior are described. Finally, specialty concrete material systems (high strength, fibrous, polymer, lightweight, refractory) are reviewed. 235 references.

  7. BIOASSAY VESSEL FAILURE ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    Vormelker, P

    2008-09-22

    Two high-pressure bioassay vessels failed at the Savannah River Site during a microwave heating process for biosample testing. Improper installation of the thermal shield in the first failure caused the vessel to burst during microwave heating. The second vessel failure is attributed to overpressurization during a test run. Vessel failure appeared to initiate in the mold parting line, the thinnest cross-section of the octagonal vessel. No material flaws were found in the vessel that would impair its structural performance. Content weight should be minimized to reduce operating temperature and pressure. Outer vessel life is dependent on actual temperature exposure. Since thermal aging of the vessels can be detrimental to their performance, it was recommended that the vessels be used for a limited number of cycles to be determined by additional testing.

  8. Analysis of the master curve approach on the fracture toughness properties of SA508 Gr.4N Ni-Mo-Cr low alloy steels for reactor pressure vessels

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ki-Hyoung, E-mail: shirimp@kaist.ac.kr [Department of Materials Science and Engineering, KAIST, Daejeon 305-701 (Korea, Republic of); Kim, Min-Chul; Lee, Bong-Sang [Nuclear Materials Research Division, KAERI, Daejeon 305-353 (Korea, Republic of); Wee, Dang-Moon [Department of Materials Science and Engineering, KAIST, Daejeon 305-701 (Korea, Republic of)

    2010-06-15

    This study aims at assessing the fracture toughness behavior of tempered martensitic Ni-Mo-Cr low alloy steels for reactor pressure vessels in a transition temperature region using a master curve approach. The fracture toughness tests for model alloys with various chemical compositions were carried out following ASTM E1921-08. The microstructures, tensile properties, and Charpy impact toughness were also evaluated. Alloying elements such as Ni, Cr, and Mo affected the mechanical properties of alloys from changes in the phase fraction and precipitation behavior. In the fracture toughness test results, the data sets showed a deviation from the median curve and a smaller scatter than that of the prediction of the ASTM standard, especially in the lower transition region. The exponential parameter of the master curve equation was adjusted by an exponential fitting to data sets for expressing well the temperature dependency of the fracture toughness. The adjusted parameter provided good agreement for data distribution and the independence of T{sub 0} from test temperatures through an overall temperature range in contrast with the results from the standard master curve.

  9. Application of Response Surface Methodology for Modeling of Postweld Heat Treatment Process in a Pressure Vessel Steel ASTM A516 Grade 70.

    Science.gov (United States)

    Peasura, Prachya

    2015-01-01

    This research studied the application of the response surface methodology (RSM) and central composite design (CCD) experiment in mathematical model and optimizes postweld heat treatment (PWHT). The material of study is a pressure vessel steel ASTM A516 grade 70 that is used for gas metal arc welding. PWHT parameters examined in this study included PWHT temperatures and time. The resulting materials were examined using CCD experiment and the RSM to determine the resulting material tensile strength test, observed with optical microscopy and scanning electron microscopy. The experimental results show that using a full quadratic model with the proposed mathematical model is YTS = -285.521 + 15.706X1 + 2.514X2 - 0.004X1(2) - 0.001X2(2) - 0.029X1X2. Tensile strength parameters of PWHT were optimized PWHT time of 5.00 hr and PWHT temperature of 645.75°C. The results show that the PWHT time is the dominant mechanism used to modify the tensile strength compared to the PWHT temperatures. This phenomenon could be explained by the fact that pearlite can contribute to higher tensile strength. Pearlite has an intensity, which results in increased material tensile strength. The research described here can be used as material data on PWHT parameters for an ASTM A516 grade 70 weld.

  10. Design and deployment of autoclave pressure vessels for the portable deep-sea drill rig MeBo (Meeresboden-Bohrgerät

    Directory of Open Access Journals (Sweden)

    T. Pape

    2017-11-01

    Full Text Available Pressure barrels for sampling and preservation of submarine sediments under in situ pressure with the robotic sea-floor drill rig MeBo (Meeresboden-Bohrgerät housed at the MARUM (Bremen, Germany were developed. Deployments of the so-called MDP (MeBo pressure vessel during two offshore expeditions off New Zealand and off Spitsbergen, Norway, resulted in the recovery of sediment cores with pressure stages equaling in situ hydrostatic pressure. While initially designed for the quantification of gas and gas-hydrate contents in submarine sediments, the MDP also allows for analysis of the sediments under in situ pressure with methods typically applied by researchers from other scientific fields (geotechnics, sedimentology, microbiology, etc.. Here we report on the design and operational procedure of the MDP and demonstrate full functionality by presenting the first results from pressure-core degassing and molecular gas analysis.

  11. Automated image segmentation and registration of vessel wall MRI for quantitative assessment of carotid artery vessel wall dimensions and plaque composition

    NARCIS (Netherlands)

    Klooster, Ronald van 't

    2014-01-01

    The main goal of this thesis was to develop methods for automated segmentation, registration and classification of the carotid artery vessel wall and plaque components using multi-sequence MR vessel wall images to assess atherosclerosis. First, a general introduction into atherosclerosis and

  12. Pressure-dependent Isotopic Composition of Iron Alloys

    Science.gov (United States)

    Reagan, M. M.; Shahar, A.; Schauble, E. A.; Caracas, R.; Gleason, A. E.; Elardo, S. M.; Xiao, Y.; Shu, J.; Mao, W. L.

    2016-12-01

    Understanding core formation, the main differentiation event in Earth's history, has important implications for our planet's geochemical and geophysical evolution, including the volatile cycle. Our current knowledge of core including formation processes as well as its composition is poorly constrained. For example, the identity of the light element present is still the subject of much debate and thus limits our understanding of the volatile cycle within the deep Earth. As carbon, hydrogen, and oxygen are all cosmochemically abundant and have been proposed as possible candidates for the main light element in planetary cores, iron isotope fractionation could be a powerful tracer of the light-element composition in the core. It has the potential to shed light on whether these volatiles are sequestered in the core or remained in the magma ocean. This talk will focus on how pressure affects fractionation factors for these iron compounds relative to the silicate mantle. We collected high pressure synchrotron nuclear resonant inelastic x-ray scattering data at Sector 16-ID-D of the Advanced Photon Source on 57Fe enriched Fe, FeO, FeHx and Fe3C from which we calculated iron isotope fractionation factors for these compounds. Our results suggest that core formation could leave an isotopic imprint on the silicate portion of Earth, which may be seen in natural samples. Moreover, the addition of different light elements or varying core formation conditions would modulate this imprint. Additionally, our results indicate that hydrogen or carbon is not likely the major light element in the core.

  13. Structural Properties of EB-Welded AlSi10Mg Thin-Walled Pressure Vessels Produced by AM-SLM Technology

    Science.gov (United States)

    Nahmany, Moshe; Stern, Adin; Aghion, Eli; Frage, Nachum

    2017-09-01

    Additive manufacturing of metals by selective laser melting (AM-SLM) is hampered by significant limitations in product size due to the limited dimensions of printing trays. Electron beam welding (EBW) is a well-established process that results in relatively minor metallurgical modifications in workpieces due to the ability of EBW to pass high-density energy to the related substance. The present study aims to evaluate structural properties of EB-welded AlSi10Mg thin-walled pressure vessels produced from components prepared by SLM technology. Following the EB welding process, leak and burst tests were conducted, as was fractography analysis. The welded vessels showed an acceptable holding pressure of 30 MPa, with a reasonable residual deformation up to 2.3% and a leak rate better than 1 × 10-8 std-cc s-1 helium. The failures that occurred under longitudinal stresses reflected the presence of two weak locations in the vessels, i.e., the welded joint region and the transition zone between the vessel base and wall. Fractographic analysis of the fracture surfaces of broken vessels displayed the ductile mode of the rupture, with dimples of various sizes, depending on the failure location.

  14. Structural Properties of EB-Welded AlSi10Mg Thin-Walled Pressure Vessels Produced by AM-SLM Technology

    Science.gov (United States)

    Nahmany, Moshe; Stern, Adin; Aghion, Eli; Frage, Nachum

    2017-10-01

    Additive manufacturing of metals by selective laser melting (AM-SLM) is hampered by significant limitations in product size due to the limited dimensions of printing trays. Electron beam welding (EBW) is a well-established process that results in relatively minor metallurgical modifications in workpieces due to the ability of EBW to pass high-density energy to the related substance. The present study aims to evaluate structural properties of EB-welded AlSi10Mg thin-walled pressure vessels produced from components prepared by SLM technology. Following the EB welding process, leak and burst tests were conducted, as was fractography analysis. The welded vessels showed an acceptable holding pressure of 30 MPa, with a reasonable residual deformation up to 2.3% and a leak rate better than 1 × 10-8 std-cc s-1 helium. The failures that occurred under longitudinal stresses reflected the presence of two weak locations in the vessels, i.e., the welded joint region and the transition zone between the vessel base and wall. Fractographic analysis of the fracture surfaces of broken vessels displayed the ductile mode of the rupture, with dimples of various sizes, depending on the failure location.

  15. Steady-state CFD simulations of an EPR™ reactor pressure vessel: A validation study based on the JULIETTE experiments

    Energy Technology Data Exchange (ETDEWEB)

    Puragliesi, R., E-mail: riccardo.puragliesi@psi.ch [Laboratory for Reactor Physics and Systems Behaviour, PSI, 5232 Villigen (Switzerland); Zhou, L. [Science and Technology on Reactor System Design Technology Laboratory, NPIC, Chengdu (China); Zerkak, O.; Pautz, A. [Laboratory for Reactor Physics and Systems Behaviour, PSI, 5232 Villigen (Switzerland)

    2016-04-15

    Highlights: • CFD validation of k–ε (RANS model of EPR RPV. • Flat inlet velocity profile is not sufficient to correctly predict the pressure drops. • Swirl is responsible for asymmetric loads at the core barrel. • Parametric study to the turbulent Schmidt number for better predictions of passive-scalar transport. • The optimal turbulent Schmidt number was found to be one order of magnitude smaller than the standard value. - Abstract: Validating computational fluid dynamics (CFD) models against experimental measurements is a fundamental step towards a broader acceptance of CFD as a tool for reactor safety analysis when best-estimate one-dimensional thermal-hydraulic codes present strong modelling limitations. In the present paper numerical results of steady-state RANS analyses are compared to pressure, volumetric flow rate and concentration distribution measurements in different locations of an Areva EPR™ reactor pressure vessel (RPV) mock-up named JULIETTE. Several flow configurations are considered: Three different total volumetric flow rates, cold leg velocity field with or without swirl, three or four reactor coolant pumps functioning. Investigations on the influence of two types of inlet boundary profiles (i.e. flat or 1/7th power-law) and the turbulent Schmidt number have shown that the first affects sensibly the pressure loads at the core barrel whereas the latter parameter strongly affects the transport and the mixing of the tracer (passive scalar) and consequently its distribution at the core inlet. Furthermore, the introduction of an integral parameter as the swirl number has helped to decrease the large epistemic uncertainty associated with the swirling device. The swirl is found to be the cause of asymmetric loads on the walls of the core barrel and also asymmetries are enhanced for the tracer concentration distribution at the core inlet. The k–ϵ CFD model developed with the commercial code STAR-CCM+ proves to be able to predict

  16. Neutron radiation embrittlement studies in support of continued operation, and validation by sampling of Magnox reactor steel pressure vessels and components

    Energy Technology Data Exchange (ETDEWEB)

    Jones, R.B.; Bolton, C.J. [Magnox Electric plc, Berkeley Centre, Glos (United Kingdom)

    1997-02-01

    Magnox steel reactor pressure vessels differ significantly from US LWR vessels in terms of the type of steel used, as well as their operating environment (dose level, exposure temperature range, and neutron spectra). The large diameter ferritic steel vessels are constructed from C-Mn steel plates and forgings joined together with manual metal and submerged-arc welds which are stress-relieved. All Magnox vessels are now at least thirty years old and their continued operation is being vigorously pursued. Vessel surveillance and other programmes are summarized which support this objective. The current understanding of the roles of matrix irradiation damage, irradiation-enhanced copper impurity precipitation and intergranular embrittlement effects is described in so far as these influence the form of the embrittlement and hardening trend curves for each material. An update is given on the influence of high temperature exposure, and on the role of differing neutron spectra. Finally, the validation offered by the results of an initial vessel sampling exercise is summarized together with the objectives of a more extensive future sampling programme.

  17. Stress analysis in a non axisymmetric loaded reactor pressure vessel; Verificacao de tensoes em um vaso de pressao nuclear com carregamentos nao-axissimetricos

    Energy Technology Data Exchange (ETDEWEB)

    Albuquerque, Levi Barcelos; Assis, Gracia Menezes V. de [Coordenadoria para Projetos Especiais (COPESP), Sao Paulo, SP (Brazil); Miranda, Carlos Alexandre J.; Cruz, Julio Ricardo B.; Mattar Neto, Miguel [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)

    1995-12-31

    In this work we intend to present the stress analysis of a PWR vessel under postulated concentrated loads. The vessel was modeled with Axisymmetric solid 4 nodes harmonic finite elements with the use of the ANSYS program, version 5.0. The bolts connecting the vessel flanges were modeled with beam elements. Some considerations were made to model the contact between the flanges. The perforated part of the vessel tori spherical head was modeled (with reduced properties due to its holes) to introduce its stiffness and loads but was not within the scope of this work. The loading consists of some usual ones, as pressure, dead weight, bolts preload, seismic load and some postulated ones as concentrated loads, over the vessel, modeled by Fourier Series. The results in the axisymmetric model are taken in terms of linearized stresses, obtained in some circumferential positions and for each position, in some sections along the vessel. Using the ASME Code (Section III, Division 1, Sub-section NB) the stresses are within the allowable limits. In order to draw some conclusions about stress linearization, the membrane plus bending stresses (Pl + Pb) are obtained and compared in some sections, using three different methods. (author) 4 refs., 15 figs., 7 tabs.

  18. ALICE HMPID Radiator Vessel

    CERN Multimedia

    2003-01-01

    View of the radiator vessels of the ALICE/HMPID mounted on the support frame. Each HMPID module is equipped with 3 indipendent radiator vessels made out of neoceram and fused silica (quartz) windows glued together. The spacers inside the vessel are needed to stand the hydrostatic pressure. http://alice-hmpid.web.cern.ch/alice-hmpid

  19. Results from the decontamination of and the shielding arrangements in the reactor pressure vessel in Oskarshamn 1-1994

    Energy Technology Data Exchange (ETDEWEB)

    Lowendahl, B. [OKG Aktiebolag, Figeholm (Sweden)

    1995-03-01

    In September 1992 Oskarshamn 1 was shut down in order to carry out measures to correct discovered deficiencies in the emergency cooling systems. Due to the results of a comprehensive non destructive test programme it was decided to perform a major replacement of pipes in the primary systems including a full system decontamination using the Siemens CORD process. The paper briefly presents the satisfying result of the decontamination performed in May-June 1993. When in late June 1993 cracks also were detected in the feed-water pipes situated inside the reactor pressure vessel (RPV) the plans were reconsidered and a large project was formed with the aim, in a first phase, to verify the integrity of the RPV. In order to make it possible to perform work manually inside the RPV special radiation protection measures had to be carried out. In January 1994 the lower region of the RPV was decontaminated, again using the CORD-process, followed by the installation of a special shielding construction in the RPV. The surprisingly good results of these efforts are also briefly described in the paper.

  20. Environmentally-Assisted Cracking of Low-Alloy Reactor Pressure Vessel Steels under Boiling Water Reactor Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Seifert, H.P.; Ritter, S

    2002-02-01

    The present report summarizes the experimental work performed by PSI on the environmentally-assisted cracking (EAC) of low-alloy steels (LAS) in the frame of the RIKORR-project during the period from January 2000 to August 2001. Within this project, the EAC crack growth behaviour of different low-alloy reactor pressure vessel (RPV) steels, weld filler and weld heat-affected zone materials is investigated under simulated transient and steady-state BWR/NWC power operation conditions. The EAC crack growth behaviour of different low-alloy RPV steels was characterized by slow rising load (SRL) / low-frequency corrosion fatigue (LFCF) and constant load tests with pre-cracked fracture mechanics specimens in oxygenated high-temperature water at temperatures of either 288, 250, 200 or 150 C. These tests revealed the following important interim results: Under low-flow and highly oxidizing (ECP >= 100 mV SHE) conditions, the ASME XI 'wet' reference fatigue crack growth curve could be significantly exceeded by cyclic fatigue loading at low frequencies (<0.001 Hz), at high and low load-ratios R, and by ripple loading near to DKth fatigue thresholds. The BWR VIP 60 SCC disposition lines may be significantly or slightly exceeded (even in steels with a low sulphur content) in the case of small load fluctuations at high load ratios (ripple loading) or at intermediate temperatures (200 -250 C) in RPV materials, which show a distinct susceptibility to dynamic strain ageing (DSA). (author)

  1. Fatigue crack growth rates in a pressure vessel steel under various conditions of loading and the environment

    Science.gov (United States)

    Hicks, P. D.; Robinson, F. P. A.

    1986-10-01

    Corrosion fatigue (CF) tests have been carried out on SA508 Cl 3 pressure vessel steel, in simulated P.W.R. environments. The test variables investigated included air and P.W.R. water environments, frequency variation over the range 1 Hz to 10 Hz, transverse and longitudinal crack growth directions, temperatures of 20 °C and 50 °C, and R-ratios of 0.2 and 0.7. It was found that decreasing the test frequency increased fatigue crack growth rates (FCGR) in P.W.R. environments, P.W.R. environment testing gave enhanced crack growth (vs air tests), FCGRs were greater for cracks growing in the longitudinal direction, slight increases in temperature gave noticeable accelerations in FCGR, and several air tests gave FCGR greater than those predicted by the existing ASME codes. Fractographic evidence indicates that FCGRs were accelerated by a hydrogen embrittlement mechanism. The presence of elongated MnS inclusions aided both mechanical fatigue and hydrogen embrittlement processes, thus producing synergistically fast FCGRs. Both anodic dissolution and hydrogen embrittlement mechanisms have been proposed for the environmental enhancement of crack growth rates. Electrochemical potential measurements and potentiostatic tests have shown that sample isolation of the test specimens from the clevises in the apparatus is not essential during low temperature corrosion fatigue testing.

  2. Impact of reaction vessel pressure on the synthesis of sliced activated carbon from date palm tree fronds

    Directory of Open Access Journals (Sweden)

    Shoaib Muhammad

    2015-01-01

    Full Text Available The effects of the reaction vessel pressure on the BET surface area, pore volume and pore size of the synthesis of sliced activated carbons (SAC at 850°C starting from 0.10 to 0.40 bars were investigated. Other synthetic variables like dwell time, CO2 flow rate and heating ramp rate were kept constant during the whole study. Methodology involves a single step procedure using the mixture of gases (N2 and CO2. During activation flow rate of both gases are kept at 150 and 50ml/min respectively. The BET surface areas of the SAC prepared at 0.10, 0.15, 0.20, 0.25, 0.30, 0.35 and 0.40 bar after 30 minutes activation time are 666, 745, 895, 1094, 835, 658 and 625 m2/g, respectively. Scanning electron microscopy (SEM for surface morphology, Energy dispersive spectroscopy (EDS, Transmission electron microscopy (TEM for nano particle size were also carried out that also confirms the same trend.

  3. Neutron fluence at the reactor pressure vessel wall - a comparison of French and German procedures and strategies in PWRs

    Energy Technology Data Exchange (ETDEWEB)

    Tricot, N. [Institut de Radioprotection et de Surete Nucleaire, IRSN/DES/SECCA, 92 - Fontenay aux Roses (France); Jendrich, U. [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH, Garching (Germany)

    2003-01-01

    While the neutrons within the core may take part in the chain reaction, those neutrons emitted from the core are basically lost for the energy production. This 'neutron leakage' represents a loss of fuel efficiency and causes neutron embrittlement of the reactor pressure vessel (RPV) wall. The latter raises safety concerns, needs to be monitored closely and may necessitate mitigating measures. There are different strategies to deal with these two undesirable effects: The neutron emission may be reduced to some extent all around the core or just at the 'hot spots' of RPV embrittlement by tailored core loading patterns. A higher absorption rate of neutrons may also be achieved by a larger water gap between the core and the RPV. In this paper the inter-relations between the distribution of neutron flux, core geometry, core loading strategy, RPV embrittlement and its surveillance are discussed at first. Then the different strategies followed by the German and French operators are described. Finally the conclusions will highlight the communalities and differences between these strategies as different approaches to the same problem of safety as well as economy. (authors)

  4. Effect of Heavy Ion Irradiation Dosage on the Hardness of SA508-IV Reactor Pressure Vessel Steel

    Directory of Open Access Journals (Sweden)

    Xue Bai

    2017-01-01

    Full Text Available Specimens of the SA508-IV reactor pressure vessel (RPV steel, containing 3.26 wt. % Ni and just 0.041 wt. % Cu, were irradiated at 290 °C to different displacement per atom (dpa with 3.5 MeV Fe ions (Fe2+. Microstructure observation and nano-indentation hardness measurements were carried out. The Continuous Stiffness Measurement (CSM of nano-indentation was used to obtain the indentation depth profile of nano-hardness. The curves showed a maximum nano-hardness and a plateau damage near the surface of the irradiated samples, attributed to different hardening mechanisms. The Nix-Gao model was employed to analyze the nano-indentation test results. It was found that the curves of nano-hardness versus the reciprocal of indentation depth are bilinear. The nano-hardness value corresponding to the inflection point of the bilinear curve may be used as a parameter to describe the ion irradiation effect. The obvious entanglement of the dislocations was observed in the 30 dpa sample. The maximum nano-hardness values show a good linear relationship with the square root of the dpa.

  5. Effects of neutron irradiation on microstructures and hardness of stainless steel weld-overlay cladding of nuclear reactor pressure vessels

    Energy Technology Data Exchange (ETDEWEB)

    Takeuchi, T., E-mail: takeuchi.tomoaki@jaea.go.jp [Oarai Research and Development Center, Japan Atomic Energy Agency, Oarai, Ibaraki 311-1393 (Japan); Kakubo, Y.; Matsukawa, Y.; Nozawa, Y.; Toyama, T.; Nagai, Y. [The Oarai Center, Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Nishiyama, Y.; Katsuyama, J.; Yamaguchi, Y.; Onizawa, K. [Nuclear Safety Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan)

    2014-06-01

    The microstructures and the hardness of stainless steel weld overlay cladding of reactor pressure vessels subjected to neutron irradiation at a dose of 7.2 × 10{sup 19} n cm{sup −2} (E > 1 MeV) and a flux of 1.1 × 10{sup 13} n cm{sup −2} s{sup −1} at 290 °C were investigated by atom probe tomography and by a nanoindentation technique. To isolate the effects of the neutron irradiation, we compared the results of the measurements of the neutron-irradiated samples with those from a sample aged at 300 °C for a duration equivalent to that of the irradiation. The Cr concentration fluctuation was enhanced in the δ-ferrite phase of the irradiated sample. In addition, enhancement of the concentration fluctuation of Si, which was not observed in the aged sample, was observed. The hardening in the δ-ferrite phase occurred due to both irradiation and aging; however, the hardening of the irradiated sample was more than that expected from the Cr concentration fluctuation, which suggested that the Si concentration fluctuation and irradiation-induced defects were possible origins of the additional hardening.

  6. Effects of thermal aging on microstructure and hardness of stainless steel weld-overlay claddings of nuclear reactor pressure vessels

    Energy Technology Data Exchange (ETDEWEB)

    Takeuchi, T., E-mail: takeuchi.tomoaki@jaea.go.jp [Japan Atomic Energy Agency, Oarai, Ibaraki 311-1393 (Japan); Kakubo, Y.; Matsukawa, Y.; Nozawa, Y.; Toyama, T.; Nagai, Y. [The Oarai Center, Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Nishiyama, Y.; Katsuyama, J.; Yamaguchi, Y.; Onizawa, K. [Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Suzuki, M. [Japan Atomic Energy Agency, Oarai, Ibaraki 311-1393 (Japan)

    2014-09-15

    The effects of thermal aging of stainless steel weld-overlay claddings of nuclear reactor pressure vessels on the microstructure and hardness of the claddings were investigated using atom probe tomography and nanoindentation testing. The claddings were aged at 400 °C for periods of 100–10,000 h. The fluctuation in Cr concentration in the δ-ferrite phase, which was caused by spinodal decomposition, progressed rapidly after aging for 100 h, and gradually for aging durations greater than 1000 h. On the other hand, NiSiMn clusters, initially formed after aging for less than 1000 h, had the highest number density after aging for 2000 h, and coarsened after aging for 10,000 h. The hardness of the δ-ferrite phase also increased rapidly for short period of aging, and saturated after aging for longer than 1000 h. This trend was similar to the observed Cr fluctuation concentration, but different from the trend seen in the formation of the NiSiMn clusters. These results strongly suggest that the primary factor responsible for the hardening of the δ-ferrite phase owing to thermal aging is Cr spinodal decomposition.

  7. Investigation of a Coolant Mixing Phenomena within the Reactor Pressure Vessel of a VVER-1000 Reactor with Different Simulation Tools

    Directory of Open Access Journals (Sweden)

    V. Sánchez

    2010-01-01

    Full Text Available The Institute of Neutron Physics and Reactor Technology (INR is involved in the qualification of coupled codes for reactor safety evaluations, aiming to improve their prediction capability and acceptability. In the frame of the VVER-1000 Coolant Transient Benchmark Phase 1, RELAP5/PARCS has been extensively assessed. Phase 2 of this benchmark was focused on both multidimensional thermal hydraulic phenomena and core physics. Plant data will be used to qualify the 3D models of TRACE and RELAP5/CFX, which were coupled for this purpose. The developed multidimensional models of the VVER-1000 reactor pressure vessel (RPV as well as the performed calculations will be described in detail. The predicted results are in good agreement with experimental data. It was demonstrated that the chosen 3D nodalization of the RPV is adequate for the description of the coolant mixing phenomena in a VVER-1000 reactor. Even though only a 3D coarse nodalization is used in TRACE, the integral results are comparable to those obtained by RELAP5/CFX.

  8. Roadmap for Nondestructive Evaluation of Reactor Pressure Vessel Research and Development by the Light Water Reactor Sustainability Program

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Cyrus M [ORNL; Nanstad, Randy K [ORNL; Clayton, Dwight A [ORNL; Matlack, Katie [Georgia Institute of Technology; Ramuhalli, Pradeep [Pacific Northwest National Laboratory (PNNL); Light, Glenn [Southwest Research Institute, San Antonio

    2012-09-01

    The Department of Energy s (DOE) Light Water Reactor Sustainability (LWRS) Program is a five year effort which works to develop the fundamental scientific basis to understand, predict, and measure changes in materials and systems, structure, and components as they age in environments associated with continued long-term operations of existing commercial nuclear power reactors. This year, the Materials Aging and Degradation (MAaD) Pathway of this program has placed emphasis on emerging Non-Destructive Evaluation (NDE) methods which support these objectives. DOE funded Research and Development (R&D) on emerging NDE techniques to support commercial nuclear reactor sustainability is expected to begin next year. This summer, the MAaD Pathway invited subject matter experts to participate in a series of workshops which developed the basis for the research plan of these DOE R&D NDE activities. This document presents the results of one of these workshops which are the DOE LWRS NDE R&D Roadmap for Reactor Pressure Vessels (RPV). These workshops made a substantial effort to coordinate the DOE NDE R&D with that already underway or planned by the Electric Power Research Institute (EPRI) and the Nuclear Regulatory Commission (NRC) through their representation at these workshops.

  9. Subaquatic, pressure vessels and LPG storage spheres internal inspection; Inspecao interna de esfera utilizando mergulho como acesso

    Energy Technology Data Exchange (ETDEWEB)

    Filgueira Filho, Rafael; Monteiro, Ayres [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2005-07-01

    Minimizing shut-down costs is a widespread target in the oil and gas industry. The use of new inspection techniques is one of the ways for that. This work presents a new procedure for internal inspections in pressure vessels by the non destructive testing - NDT, ACFM, using industrial diving techniques. As a pioneer experience, this method was applied in the inspection of the internal parts of the LPG sphere tank 5101 at PETROBRAS Transporte S.A. - TRANSPETRO, in Jequie's Terminal, in the state of Bahia, in december, 2003. This new method allows the reduction of indirect costs related to operational unavailability of the equipment, by the reduction of the shut-down time in approximately 50%, when compared to the demanded shut down time, when using scaffolds for accessing the internal parts. Despite of direct costs are still higher with the new methodology, this paper demonstrates the economical feasibility of this new method, based on the savings obtained with the fastest return of the equipment to operation. (author)

  10. Specific Features of Structural-Phase State and Properties of Reactor Pressure Vessel Steel at Elevated Irradiation Temperature

    Directory of Open Access Journals (Sweden)

    E. A. Kuleshova

    2017-01-01

    Full Text Available This paper considers influence of elevated irradiation temperature on structure and properties of 15Kh2NMFAA reactor pressure vessel (RPV steel. The steel is investigated after accelerated irradiation at 300°C (operating temperature of VVER-1000-type RPV and 400°C supposed to be the operating temperature of advanced RPVs. Irradiation at 300°C leads to formation of radiation-induced precipitates and radiation defects-dislocation loops, while no carbide phase transformation is observed. Irradiation at a higher temperature (400°C neither causes formation of radiation-induced precipitates nor provides formation of dislocation loops, but it does increase the number density of the main initial hardening phase—of the carbonitrides. Increase of phosphorus concentration in grain boundaries is more pronounced for irradiation at 400°C as compared to irradiation at 300°C due to influence of thermally enhanced diffusion at a higher temperature. The structural-phase changes determine the changes of mechanical properties: at both irradiation temperatures irradiation embrittlement is mainly due to the hardening mechanism with some contribution of the nonhardening one for irradiation at 400°C. Lack of formation of radiation-induced precipitates at T = 400°C provides a small ΔTK shift (17°C. The obtained results demonstrate that the investigated 15Kh2NMFAA steel may be a promising material for advanced reactors with an elevated operating temperature.

  11. Collapsible Cryogenic Storage Vessel Project

    Science.gov (United States)

    Fleming, David C.

    2002-01-01

    Collapsible cryogenic storage vessels may be useful for future space exploration missions by providing long-term storage capability using a lightweight system that can be compactly packaged for launch. Previous development efforts have identified an 'inflatable' concept as most promising. In the inflatable tank concept, the cryogen is contained within a flexible pressure wall comprised of a flexible bladder to contain the cryogen and a fabric reinforcement layer for structural strength. A flexible, high-performance insulation jacket surrounds the vessel. The weight of the tank and the cryogen is supported by rigid support structures. This design concept is developed through physical testing of a scaled pressure wall, and through development of tests for a flexible Layered Composite Insulation (LCI) insulation jacket. A demonstration pressure wall is fabricated using Spectra fabric for reinforcement, and burst tested under noncryogenic conditions. An insulation test specimens is prepared to demonstrate the effectiveness of the insulation when subject to folding effects, and to examine the effect of compression of the insulation under compressive loading to simulate the pressure effect in a nonrigid insulation blanket under the action atmospheric pressure, such as would be seen in application on the surface of Mars. Although pressure testing did not meet the design goals, the concept shows promise for the design. The testing program provides direction for future development of the collapsible cryogenic vessel concept.

  12. News from the Library: A new key reference work for the engineer: ASME's Boiler and Pressure Vessel Code at the CERN Library

    CERN Document Server

    CERN Library

    2011-01-01

    The Library is aiming at offering a range of constantly updated reference books, to cover all areas of CERN activity. A recent addition to our collections strengthens our offer in the Engineering field.   The CERN Library now holds a copy of the complete ASME Boiler and Pressure Vessel Code, 2010 edition. This code establishes rules of safety governing the design, fabrication, and inspection of boilers and pressure vessels, and nuclear power plant components during construction. This document is considered worldwide as a reference for mechanical design and is therefore important for the CERN community. The Code published by ASME (American Society of Mechanical Engineers) is kept current by the Boiler and Pressure Committee, a volunteer group of more than 950 engineers worldwide. The Committee meets regularly to consider requests for interpretations, revision, and to develop new rules. The CERN Library receives updates and includes them in the volumes until the next edition, which is expected to ...

  13. Compositional dependence of structural transition pressures in amorphous phases with mantle-related compositions

    Science.gov (United States)

    Shim, Sang-Heon; Catalli, Krystle

    2009-06-01

    Properties of silicate melts are key to understanding the evolution of the mantles of the Earth and terrestrial planets. Although remarkable progress has been made in first-principle calculations for melts in recent years, structural measurements of silicate melts at in situ high P-T remain one of the most challenging tasks. The study of glasses, kinetically frozen melts, at high pressure can provide valuable insights into related melts in the mantle. We report Raman scattering of MgSiO 3 glass revealing a structural transition at 19-38 GPa, which is associated with increases in the Si sbnd O coordination number, and another transition at 65-70 GPa. However, in CaSiO 3 and Mg 2SiO 4 glasses, the former transition occurs at higher pressures by 5-10 GPa and the latter transition is not observed to our maximum pressure (80 GPa), indicating that a less polymerized Si sbnd O network increases the transition pressures. Our results suggest that the pressure for the structural transitions in these glasses is influenced strongly by the concentration of network former cations and the ionic size of the network modifiers. This observation may have important implications for compositional differentiation in the early magma ocean and the present-day mantle.

  14. Movement of retinal vessels toward the optic nerve head after increasing intraocular pressure in monkey eyes with experimental glaucoma.

    Science.gov (United States)

    Kuroda, Atsumi; Enomoto, Nobuko; Ishida, Kyoko; Shimazawa, Masamitsu; Noguchi, Tetsuro; Horai, Naoto; Onoe, Hirotaka; Hara, Hideaki; Tomita, Goji

    2017-09-01

    A shift or displacement of the retinal blood vessels (RBVs) with neuroretinal rim thinning indicates the progression of glaucomatous optic neuropathy. In chronic open angle glaucoma, individuals with RBV positional shifts exhibit more rapid visual field loss than those without RBV shifts. The retinal vessels reportedly move onto the optic nerve head (ONH) in response to glaucoma damage, suggesting that RBVs are pulled toward the ONH in response to increased cupping. Whether this phenomenon only applies to RVBs located in the vicinity or inside the ONH or, more generally, to RBVs also located far from the ONH, however, is unclear. The aim of this study was to evaluate the movement of RBVs located relatively far from the ONH edge after increasing intraocular pressure (IOP) in an experimental monkey model of glaucoma. Fundus photographs were obtained in 17 monkeys. High IOP was induced in the monkeys by laser photocoagulation burns applied uniformly with 360° irradiation around the trabecular meshwork of the left eye. The right eye was left intact and used as a non-treated control. Considering the circadian rhythm of IOP, it was measured in both eyes of each animal at around the same time-points. Then, fundus photographs were obtained. Using Image J image analysis software, an examiner (N.E.) measured the fundus photographs at two time-points, i.e. before laser treatment (time 1) and the last fundus photography after IOP elevation (time 2). The following parameters were measured (in pixels): 1) vertical diameter of the ONH (DD), 2) distance from the ONH edge to the first bifurcation point of the superior branch of the central retinal vein (UV), 3) distance from the ONH edge to the first bifurcation point of the inferior branch of the central retinal vein (LV), 4) ONH area, and 5) surface area of the cup of the ONH. We calculated the ratios of UV to DD (UV/DD), LV to DD (LV/DD), and the cup area to disc area ratio (C/D). The mean UV/DD at time 1 (0.656 ± 0.233) was

  15. Curing Pressure Influence of Out-of-Autoclave Processing on Structural Composites for Commercial Aviation

    National Research Council Canada - National Science Library

    Drakonakis, Vasileios M; Seferis, James C; Doumanidis, Charalambos C

    2013-01-01

    ...) composite structures used in aviation. During the autoclave process, consolidation of prepreg laminas through simultaneous elevated pressure and temperature results in a uniform high-end material system...

  16. Chemical composition of bioactive pressurized extracts of Romanian aromatic plants.

    Science.gov (United States)

    Miron, T L; Plaza, M; Bahrim, G; Ibáñez, E; Herrero, M

    2011-07-29

    In this contribution, pressurized liquid extraction (PLE) has been employed to isolate bioactive compounds from three native Romanian plants, oregano (Origanum vulgare), tarragon (Artemisia dracunculus) and wild thyme (Thymus serpyllum). Different PLE conditions have been tested including extraction with water, ethanol and their mixtures in a wide range of extraction temperatures (50-200°C), and the antioxidant capacity of the extracts was measured using different assays (DPPH radical scavenging, TEAC assay and Folin-Ciocalteau assay to measure total phenols). Moreover, a complete chemical characterization by using LC-MS/MS was carried out to be able to correlate the bioactivity with the particular chemical composition of each extract and plant. The use of PLE with water as a solvent at the highest temperature tested (200°C) always provided the highest extraction yields for the three studied plants, being maximum for oregano (>60%). Besides, oregano's pressurized water extracts at lower temperatures (50°C) presented the highest content on total phenols (184.9 mg gallic acid/g extract) and the best antioxidant activities (EC(50) 6.98 μg/ml). In general, oregano extracts were the most active, followed by wild thyme extracts. The antioxidant capacity measured by DPPH assay was highly correlated with the amount of total phenols. Moreover, the use of a LC-MS/MS method allowed the identification of 30 different phenolic compounds in the different extracts, including phenolic acids, flavones, flavanones and flavonols, which have an important influence on the total antioxidant capacity of the different extracts. Copyright © 2010 Elsevier B.V. All rights reserved.

  17. Automated Manufacture of Damage Detecting, Self-Healing Composite Cryogenic Pressure Vessels Project

    Data.gov (United States)

    National Aeronautics and Space Administration — During Phase I, Aurora Flight Sciences and the University of Massachusetts Lowell propose to demonstrate the feasibility of enhancing a commercially available...

  18. Considerations for Using Composite Pressure Vessels (CPVs) in Fuel Storage for Automotive Applications

    Science.gov (United States)

    Cone, Darren; Greene, Nathanael; Beeson, Harold; McCloskey, David

    2013-01-01

    Ongoing initiative to get high energy capacity "green fuel" containers to market quickly and cost effectively. The United States has decided to invest in "green energy" technology, to become energy independent, and to "Innovate Our Way to a Clean Energy Future."

  19. Testing of Carbon Fiber Composite Overwrapped Pressure Vessel Stress-Rupture Lifetime

    Science.gov (United States)

    Grimes-Ledesma, Lorie; Phoenix, S. Leigh; Beeson, Harold; Yoder, Tommy; Greene, Nathaniel

    2006-01-01

    This paper contains summaries of testing procedures and analysis of stress rupture life testing for two stress rupture test programs, one for Kevlar COPVs performed at Lawrence Livermore National Laboratory, and the other a joint study between NASA JSC White Sands Test Facility and the Jet Propulsion Laboratory. These will be discussed in detail including test setup and issues encountered during testing. Lessons learned from testing in these two programs will be discussed.

  20. Photonic Sensor for Nondestructive Testing of Composite Overwrapped Pressure Vessels Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Los Gatos Research proposes to develop a photonic sensor instrumentation, capable of monitoring distributed load and acoustic emission (AE) for rapid inspection of...

  1. Photonic Sensor for Nondestructive Testing of Composite Overwrapped Pressure Vessels Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Los Gatos Research proposes to develop a new automated health monitoring sensor system capable of monitoring distributed load and acoustic emission (AE) for rapid...

  2. Weldability and toughness evaluation of pressure vessel quality steel using the shielded metal arc welding (SMAW) process

    Science.gov (United States)

    Datta, R.; Mukerjee, D.; Mishra, S.

    1998-12-01

    The present study was carried out to assess the weldability properties of ASTM A 537 Cl. 1 pressure-vessel quality steel using the shielded metal arc welding (SMAW) process. Implant and elastic restraint cracking (ERC) tests were conducted under different welding conditions to determine the cold cracking susceptibility of the steel. The static fatigue limit values determined for the implant test indicate adequate resistance to cold cracking even with unbaked electrodes. The ERC test, however, established the necessity to rebake the electrodes before use. Lamellar tearing tests carried out using full-thickness plates under three welding conditions showed no incidence of lamellar tearing upon visual examination, ultrasonic inspection, and four-section macroexamination. Lamellar tearing tests were repeated using machined plates, such that the central segregated band located at the midthickness of the plate corresponded to the heat-affected zone (HAZ) of the weld. Only in one (no rebake, heat input: 14.2 kj cm-1, weld restraint load: 42 kg mm-2) of the eight samples tested was lamellar tearing observed. This was probably accentuated due to the combined effects of the presence of localized pockets of a hard phase (bainite) and a high hydrogen level (unbaked electrodes) in the weld joint. Optimal welding conditions were formulated based on the above tests. The weld joint was subjected to extensive tests and found to exhibit excellent strength (tensile strength: 56.8 kg mm-2, or 557 MPa), and low temperature impact toughness (7.4 and 4.5 kg-m at-20 °C for weld metal, WM, and HAZ) properties. Crack tip opening displacement tests carried out for the WM and HAZ resulted in δm values 0.36 and 0.27 mm, respectively, which indicates adequate resistance to brittle fracture.

  3. Nanostructure evolution under irradiation of Fe(C)MnNi model alloys for reactor pressure vessel steels

    Energy Technology Data Exchange (ETDEWEB)

    Chiapetto, M., E-mail: mchiapet@sckcen.be [SCK-CEN, Nuclear Materials Science Institute, Boeretang 200, B-2400 Mol (Belgium); Unité Matériaux Et Transformations (UMET), UMR 8207, Université de Lille 1, ENSCL, F-59600 Villeneuve d’Ascq Cedex (France); Becquart, C.S. [Unité Matériaux Et Transformations (UMET), UMR 8207, Université de Lille 1, ENSCL, F-59600 Villeneuve d’Ascq Cedex (France); Laboratoire commun EDF-CNRS Etude et Modélisation des Microstructures pour le Vieillissement des Matériaux (EM2VM) (France); Domain, C. [EDF R& D, Département Matériaux et Mécanique des Composants, Les Renardières, F-77250 Moret sur Loing (France); Laboratoire commun EDF-CNRS Etude et Modélisation des Microstructures pour le Vieillissement des Matériaux (EM2VM) (France); Malerba, L. [SCK-CEN, Nuclear Materials Science Institute, Boeretang 200, B-2400 Mol (Belgium)

    2015-06-01

    Radiation-induced embrittlement of bainitic steels is one of the most important lifetime limiting factors of existing nuclear light water reactor pressure vessels. The primary mechanism of embrittlement is the obstruction of dislocation motion produced by nanometric defect structures that develop in the bulk of the material due to irradiation. The development of models that describe, based on physical mechanisms, the nanostructural changes in these types of materials due to neutron irradiation are expected to help to better understand which features are mainly responsible for embrittlement. The chemical elements that are thought to influence most the response under irradiation of low-Cu RPV steels, especially at high fluence, are Ni and Mn, hence there is an interest in modelling the nanostructure evolution in irradiated FeMnNi alloys. As a first step in this direction, we developed sets of parameters for object kinetic Monte Carlo (OKMC) simulations that allow this to be done, under simplifying assumptions, using a “grey alloy” approach that extends the already existing OKMC model for neutron irradiated Fe–C binary alloys [1]. Our model proved to be able to describe the trend in the buildup of irradiation defect populations at the operational temperature of LWR (∼300 °C), in terms of both density and size distribution of the defect cluster populations, in FeMnNi model alloys as compared to Fe–C. In particular, the reduction of the mobility of point-defect clusters as a consequence of the presence of solutes proves to be key to explain the experimentally observed disappearance of detectable point-defect clusters with increasing solute content.

  4. Fracture mechanics characterisation of the WWER-440 reactor pressure vessel beltline welding seam of Greifswald unit 8

    Energy Technology Data Exchange (ETDEWEB)

    Viehrig, Hans-Werner; Schuhknecht, Jan [Forschungszentrum Dresden-Rossendorf (Germany)

    2008-07-01

    WWER-440 second generation (V-213) reactor pressure vessels (RPV) were produced by IZHORA in Russia and by SKODA in the former Czechoslovakia. The surveillance Charpy-V and fracture mechanics SE(B) specimens of both producers have different orientations. The main difference is the crack extension direction which is through the RPV thickness and circumferential for ISHORA and SKODA RPV, respectively. In particular for the investigation of weld metal from multilayer submerged welding seams the crack extension direction is of importance. Depending on the crack extension direction in the specimen there are different welding beads or a uniform structure along the crack front. The specimen orientation becomes more important when the fracture toughness of the weld metal is directly determined on surveillance specimens according to the Master Curve (MC) approach as standardised in the ASTM Standard Test Method E1921. This approach was applied on weld metal of the RPV beltline welding seam of Greifswald Unit 8 RPV. Charpy size SE(B) specimens from 13 locations equally spaced over the thickness of the welding seam were tested. The specimens are in TL and TS orientation. The fracture toughness values measured on the SE(B) specimens with both orientations follow the course of the MC. Nearly all values lie within the fracture toughness curves for 5% and 95% fracture probability. There is a strong variation of the reference temperature T{sub 0} though the thickness of the welding seam, which can be explained with structural differences. The scatter is more pronounced for the TS SE(B) specimens. It can be shown that specimens with TS and TL orientation in the welding seam have a differentiating and integrating behaviour, respectively. The statistical assumptions behind the MC approach are valid for both specimen orientations even if the structure is not uniform along the crack front. By comparison crack extension, JR, curves measured on SE(B) specimens with TL and TS orientation

  5. Containment vessel drain system

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Scott G.

    2018-01-30

    A system for draining a containment vessel may include a drain inlet located in a lower portion of the containment vessel. The containment vessel may be at least partially filled with a liquid, and the drain inlet may be located below a surface of the liquid. The system may further comprise an inlet located in an upper portion of the containment vessel. The inlet may be configured to insert pressurized gas into the containment vessel to form a pressurized region above the surface of the liquid, and the pressurized region may operate to apply a surface pressure that forces the liquid into the drain inlet. Additionally, a fluid separation device may be operatively connected to the drain inlet. The fluid separation device may be configured to separate the liquid from the pressurized gas that enters the drain inlet after the surface of the liquid falls below the drain inlet.

  6. Cyclic Crack Growth Testing of an A.O. Smith Multilayer Pressure Vessel with Modal Acoustic Emission Monitoring and Data Assessment

    Science.gov (United States)

    Ziola, Steven M.

    2014-01-01

    Digital Wave Corp. (DWC) was retained by Jacobs ATOM at NASA Ames Research Center to perform cyclic pressure crack growth sensitivity testing on a multilayer pressure vessel instrumented with DWC's Modal Acoustic Emission (MAE) system, with captured wave analysis to be performed using DWCs WaveExplorerTM software, which has been used at Ames since 2001. The objectives were to document the ability to detect and characterize a known growing crack in such a vessel using only MAE, to establish the sensitivity of the equipment vs. crack size and / or relevance in a realistic field environment, and to obtain fracture toughness materials properties in follow up testing to enable accurate crack growth analysis. This report contains the results of the testing.

  7. Heating of reactor pressure vessel bottom head and penetrations in a severe reactor accident; Reaktoripaineastian pohjan ja laepivientien kuumeneminen sydaemen sulamisonnettomuudessa

    Energy Technology Data Exchange (ETDEWEB)

    Ikonen, K. [VTT Energy, Espoo (Finland). Nuclear Energy

    1997-10-01

    The report describes the fundamentals of heat conductivity and convection and numerical methods like finite difference and control volume method for calculation of the thermal history of a reactor pressure vessel bottom head and penetrations. Phase changes from solids to liquids are considered. Time integration is performed by explicit or implicit method. Developed computer codes for thermal conductivity and convection analyses and codes for graphical visualization are described. The codes are applied to two practical cases. They deal with analyses of Swiss CORVIS-experiments and analyses of control rod and instrument penetrations in a BWR bottom head. A model for calculation of effective thermal conductivity of granular corium is developed. The work is also related to EU MVI-project (Core Melt-Pressure Vessel Interactions During a Light Water Reactor Severe Accident), whose coordinator is Prof. B. R. Sehgal at Royal Institute of Technology in Stockholm. (orig.) (11 refs.).

  8. On the role of sulfur on the dissolution of pressure vessel steels at the tip of a propagating crack in PWR environments

    Energy Technology Data Exchange (ETDEWEB)

    Combrade, P.; Foucault, M. (UNIREC 42- Firminy (FR)); Marcus, P. (Ecole Nationale Superieure de Chimie 75 - Paris (FR)); Slama, G. (Societe Franco-Americaine de Constructions Atomiques (Framatome), 92 - Courbevoie (FR))

    1990-03-01

    Different aspects of the effect of sulfur on the dissolution and film repair on pressure vessel steel exposed to PWR environment at 300{sup 0}C were examined. A monolayer of sulfur adsorbed on a bare surface was shown to inhibit the nucleation of a magnetite film. The comparison of this result with dissolution measurements performed by using CERT under controlled potential lead to the assumption that mechanical rupture steps are involved in the environmental effect on the crack propagation rate. 27 refs.

  9. Mix Model of FE Method and IPSO Algorithm for Dome Shape Optimization of Articulated Pressure Vessels Considering the Effect of Non-geodesic Trajectories

    Science.gov (United States)

    Paknahad, A.; Nourani, R.

    2014-04-01

    The main essential topic for the design of articulated pressure vessels is related to the determination of the optimal meridian profile. This article, aimed to present the new model for optimum design of dome contours for filament wound articulated pressure vessels based on non-geodesic trajectories. The current model is a mix of finite element analysis and inertia weight particle swarm optimization algorithm. Geometrical limitations, stability-ensuring winding conditions and the Tsai-Wu failure criterion have been used as optimization constraints. Classical lamination theory and non-geodesic trajectories are used to analyse the field stress equations and increase the structural performance. The geometry of dome contours is defined by the B-spline curves with twenty-one points. The results, when compared to the previously published results, indicate the efficiency of the presented model in achieving superior performance of dome shape for articulated pressure vessels. Also, it is shown that the design based on non-geodesic trajectories using this model gains better response than the design by geodesics type.

  10. Development of Mini-Compact Tension Test Method for Determining Fracture Toughness Master Curves for Reactor Pressure Vessel Steels

    Energy Technology Data Exchange (ETDEWEB)

    Sokolov, Mikhail A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-05-01

    Small specimens are playing the key role in evaluating properties of irradiated materials. The use of small specimens provides several advantages. Typically, only a small volume of material can be irradiated in a reactor at desirable conditions in terms of temperature, neutron flux, and neutron dose. A small volume of irradiated material may also allow for easier handling of specimens. Smaller specimens reduce the amount of radioactive material, minimizing personnel exposures and waste disposal. However, use of small specimens imposes a variety of challenges as well. These challenges are associated with proper accounting for size effects and transferability of small specimen data to the real structures of interest. Any fracture toughness specimen that can be made out of the broken halves of standard Charpy specimens may have exceptional utility for evaluation of reactor pressure vessels (RPVs) since it would allow one to determine and monitor directly actual fracture toughness instead of requiring indirect predictions using correlations established with impact data. The Charpy V-notch specimen is the most commonly used specimen geometry in surveillance programs. Validation of the mini compact tension specimen (mini-CT) geometry has been performed on previously well characterized Midland beltline Linde 80 (WF-70) weld in the unirradiated condition. It was shown that the fracture toughness transition temperature, To, measured by these Mini-CT specimens is almost the same as To value that was derived from various larger fracture toughness specimens. Moreover, an International collaborative program has been established to extend the assessment and validation efforts to irradiated Linde 80 weld metal. The program is underway and involves the Oak Ridge National Laboratory (ORNL), Central Research Institute for Electrical Power Industry (CRIEPI), and Electric Power Research Institute (EPRI). The irradiated Mini-CT specimens from broken halves of previously tested Charpy

  11. Fracture mechanics characterisation of the WWER-440 reactor pressure vessel beltline welding seam of Greifswald unit 8

    Energy Technology Data Exchange (ETDEWEB)

    Viehrig, Hans-Werner; Schuhknecht, Jan [Forschungszentrum Dresden-Rossendorf, Dresden (Germany)

    2009-07-01

    Russian type WWER reactors are operated in Russia and many other European countries like Finland, Czech Republic, Slovak Republic, Hungary, Bulgaria and Ukraine. Surveillance specimen programmes for the inspection of the aging of the reactor pressure vessel (RPV) materials were implemented for the second generation of WWER-440/V-213 reactors. The test results and the RPV integrity assessment has been evaluated according to national codes based on the Russian code PNAE G-7-002-86 ''Strength Calculation Norms for Nuclear Power Plant Equipment and Piping'' [1]. This is an indirect and correlative approach of determining the fracture toughness of the RPV steels in the initial and irradiated condition. The Master Curve (MC) approach as adopted in the test procedure ASTM E1921 [2] for assessing the fracture toughness of sampled irradiated materials has been gaining acceptance throughout the world [3]. The MC approach is more naturally suited to probabilistic analyses because it defines both a mean transition toughness value and a distribution around that value. It contains the assumptions of macroscopically homogenous material with uniform distribution of crack initiating defects along the crack front. In contrast to present indirect and correlative approach the specimen orientation and especially the crack extension direction in multilayer weld metal becomes more important for the direct measurement of the fracture toughness with Charpy size SE(B) specimens. The orientation of the Charpy- and SE(B) specimens is different for RPVs manufactured in Russia and by the SKODA company in the former Czechoslovakia [4,5]. Particularly with regard to weld metal it can be expected that the parameters of fracture toughness measured with Charpy-V or SE(B) specimens are strongly influenced by the specimen orientation. It raises the question whether the MC approach is also applicable when the structure varies along the crack front which is happen in TL oriented SE

  12. A non-hypocholesterolemic atorvastatin treatment improves vessel elasticity by acting on elastin composition in WHHL rabbits.

    Science.gov (United States)

    Tissier, Florine; Mallem, Yassine; Goanvec, Christelle; Didier, Romain; Aubry, Thierry; Bourgeois, Nathalie; Desfontis, Jean-Claude; Dubreuil, Matthieu; Le Grand, Yann; Mansourati, Jacques; Pichavant-Rafini, Karine; Plee-Gautier, Emmanuelle; Roquefort, Philippe; Theron, Michael; Gilard, Martine

    2016-08-01

    Statins are prescribed for their preventative effects within atherosclerosis development. To our knowledge, no study focusing on very low-dose (non-hypolipidemic effect) and long-term atorvastatin treatment in vivo was available. Our aim was to assess the effect of such atorvastatin treatment on the mechanical and functional characteristics of arteries in the context of primary prevention. An atorvastatin treatment (2.5 mg/kg/day) was tested against controls on 34 male 3 to 12 month-old WHHL rabbits. No effect on total cholesterol, triglycerides, HDL or LDL was observed. The arterial stiffness was evaluated on vigil animals by pulse wave velocity (PWV) measurement. Then, in vitro measurements were made to evaluate (1) the endothelial and vascular smooth muscle function, (2) the elasticity of the arterial wall and (3) the composition in collagen and elastin in the aorta. The PWV increasing observed with age in control group was canceled by treatment, creating a significance difference between groups at 12 months (5.17 ± 0.50 vs 2.14 ± 0.34 m s(-1) in control and treated groups respectively). Vasoreactivity modifications can't explain this result but maintain of elasticity with treatment in large arteries was confirm by a static tensile test. A first possible explanation is the change of wall composition with treatment, validated by the percentage of elastin at 12 months, 4.4% lower in the control group compared to the treated group (p < 0.05). This study shows that a non-hypocholesterolemic statin treatment could improve vessel elasticity in the atherosclerotic WHHL model. The great novelty of this work is the vessel wall composition changing associated. This first approach in animal opens the reflection on the use of these low doses in humans. This could be interesting in the context of arterial stiffening with aging, non-hyperlipidemic atherosclerosis or with cholesterol reduce by another therapy or lifestyle modification. Copyright © 2016 Elsevier

  13. Stem Hydraulic Conductivity depends on the Pressure at Which It Is Measured and How This Dependence Can Be Used to Assess the Tempo of Bubble Pressurization in Recently Cavitated Vessels1[OPEN

    Science.gov (United States)

    Liu, Jinyu; Tyree, Melvin T.

    2015-01-01

    Cavitation of water in xylem vessels followed by embolism formation has been authenticated for more than 40 years. Embolism formation involves the gradual buildup of bubble pressure (air) to atmospheric pressure as demanded by Henry’s law of equilibrium between gaseous and liquid phases. However, the tempo of pressure increase has not been quantified. In this report, we show that the rate of pressurization of embolized vessels is controlled by both fast and slow kinetics, where both tempos are controlled by diffusion but over different spatial scales. The fast tempo involves a localized diffusion from endogenous sources: over a distance of about 0.05 mm from water-filled wood to the nearest embolized vessels; this process, in theory, should take measurements both confirm that the average time constant is >17 h, with complete equilibrium requiring 1 to 2 d. The implications of these timescales for the standard methods of measuring percentage loss of hydraulic conductivity are discussed in theory and deserve more research in future. PMID:26468516

  14. Stem Hydraulic Conductivity depends on the Pressure at Which It Is Measured and How This Dependence Can Be Used to Assess the Tempo of Bubble Pressurization in Recently Cavitated Vessels.

    Science.gov (United States)

    Wang, Yujie; Liu, Jinyu; Tyree, Melvin T

    2015-12-01

    Cavitation of water in xylem vessels followed by embolism formation has been authenticated for more than 40 years. Embolism formation involves the gradual buildup of bubble pressure (air) to atmospheric pressure as demanded by Henry's law of equilibrium between gaseous and liquid phases. However, the tempo of pressure increase has not been quantified. In this report, we show that the rate of pressurization of embolized vessels is controlled by both fast and slow kinetics, where both tempos are controlled by diffusion but over different spatial scales. The fast tempo involves a localized diffusion from endogenous sources: over a distance of about 0.05 mm from water-filled wood to the nearest embolized vessels; this process, in theory, should take measurements both confirm that the average time constant is >17 h, with complete equilibrium requiring 1 to 2 d. The implications of these timescales for the standard methods of measuring percentage loss of hydraulic conductivity are discussed in theory and deserve more research in future. © 2015 American Society of Plant Biologists. All Rights Reserved.

  15. Vessel Operating Units (Vessels)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains data for vessels that are greater than five net tons and have a current US Coast Guard documentation number. Beginning in1979, the NMFS...

  16. Final Report for the 1st Surveillance Test of the Reactor Pressure Vessel Material (Capsule 2) of Ulchin Nuclear Power Plant Unit 4

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Kee Ok; Kim, Byoung Chul; Lee, Sam Lai (and others)

    2007-04-15

    Surveillance testing for reactor vessel materials is performed in order to evaluate the irradiation embrittlement due to neutrons during operation and set the condition of safe operation of nuclear reactor. The 1st surveillance testing was performed completely by Korea Atomic Energy Research Institute at Daejon after the capsule was transported from Ulchin site including its removal from reactor. Fast neutron fluences for capsules were calculated and various testing including mechanical and chemistry analysis were performed in order to evaluate the integrity of Ulchin Unit 4 reactor vessel during the operation until life time. The evaluation results are as follows; Fast neutron fluences for capsule 2 is 4.306E+18n/cm{sup 2}. The bias factor, the ratio of calculation/measurement, was 0.918 for the 1st testing and the calculational uncertainty,7.0% satisfied the requirement of USNRC Reg.Guide 1.190, 20%. The best estimated neutron fluence for reactor vessel inside surface was 3.615E+18n/cm{sup 2} based on the end of 6th fuel cycle and it was predicted that the fluences of vessel inside surface at 16 and 32EFPY would reach 8.478E+18 and 1.673E+19n/cm{sup 2} based on the current calculation. The result through this analysis for Ulchin Unit 4 showed that there would be no problem for the pressurized thermal shock(PTS) during the operation until design life.

  17. Final Report for the 1st Surveillance Test of the Reactor Pressure Vessel Material (CAPSULE 2) of Ulchin Nuclear Power Plant Unit 3

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Kee Ok; Kim, Byoung Chul; Lee, Sam Lai (and others)

    2006-12-15

    Surveillance testing for reactor vessel materials is performed in order to evaluate the irradiation embrittlement due to neutrons during operation and set the condition of safe operation of nuclear reactor. The 1st surveillance testing was performed completely by Korea Atomic Energy Research Institute at Taejon after the capsule was transported from Ulchin site including its removal from reactor. Fast neutron fluences for capsules were calculated and various testing including mechanical and chemistry analysis were performed in order to evaluate the integrity of Ulchin unit 3 reactor vessel during the operation until life time. The evaluation results are as follows; Fast neutron fluences for capsule 2 is 4.674E 18n/cm{sup 2}. The bias factor, the ratio of calculation/measurement, was 0.920 for the 1st testing and the calculational uncertainty,7.0% satisfied the requirement of USNRC Reg.Guide 1.190, 20%. The best estimated neutron fluence for reactor vessel inside surface was 3.913E 18n/cm{sup 2} based on the end of 6th fuel cycle and it was predicted that the fluences of vessel inside surface at 16 and 32EFPY would reach 9.249E 18 and 1.834E 19n/cm{sup 2} based on the current calculation. The result through this analysis for Ulchin unit 3 showed that there would be no problem for the pressurized thermal shock(PTS) during the operation until design life.

  18. Effect of simulated pulpal pressure on composite bond strength to ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-10-19

    Oct 19, 2009 ... Bonding to dentin with adhesive systems is affected by the tubular fluid flow induced by pulpal pressure. The aim of this study was to evaluate the effect of simulated pulpal pressure on the microtensile bond strength of an adhesive to dentin surface prepared by laser irradiation. Crowns of twenty human ...

  19. Effect of simulated pulpal pressure on composite bond strength to ...

    African Journals Online (AJOL)

    Bonding to dentin with adhesive systems is affected by the tubular fluid flow induced by pulpal pressure. The aim of this study was to evaluate the effect of simulated pulpal pressure on the microtensile bond strength of an adhesive to dentin surface prepared by laser irradiation. Crowns of twenty human extracted third ...

  20. Experimental and numerical investigation of coolant mixing in a model of reactor pressure vessel down-comer and in cold leg inlets

    Directory of Open Access Journals (Sweden)

    Hutli Ezddin

    2017-01-01

    Full Text Available Thermal fatigue and pressurized thermal shock phenomena are the main problems for the reactor pressure vessel and the T-junctions both of them depend on the mixing of the coolant. The mixing process, flow and temperature distribution has been investigated experimentally using particle image velocimetry, laser induced fluorescence, and simulated by CFD tools. The obtained results showed that the ratio of flow rate between the main pipe and the branch pipe has a big influence on the mixing process. The particle image velocimetry/planar laser-induced fluorescence measurements technologies proved to be suitable for the investigation of turbulent mixing in the complicated flow system: both velocity and temperature distribution are important parameters in the determination of thermal fatigue and pressurized thermal shock. Results of the applied these techniques showed that both of them can be used as a good provider for data base and to validate CFD results.

  1. Multifunctional Metal Matrix Composite Filament Wound Tank Liners Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Composite Overwrapped Pressure Vessels (COPVs) are used for storing pressurized gases on board spacecraft when mass saving is a key requirement. All future mass...

  2. Imbedded fiber optic pressure and temperature sensors enable cure monitoring of pultruded composite materials

    Science.gov (United States)

    Cable, David

    1990-05-01

    The application of fiberoptic multifunction sensing system for the measurement of temperature and pressure during the curing of fiberglass/epoxy composite structure is described. The system employs interferometric principles to measure temperature, pressure, and refractive index of liquids as well as other physical parameters. Fiberoptic pressure and temperature sensors have been employed in monitoring composites pultrusion and molding. The system is ideally suited for monitoring a variety of composite curing processes because of the sensor's microminiature size, tolerance of moderately high temperatures, non-metallic construction, and inherent immunity to electromagnetic and radio frequency signals.

  3. Turbulence characterization of a high-pressure high-temperature fan-stirred combustion vessel using LDV, PIV and TR-PIV measurements

    Science.gov (United States)

    Galmiche, Bénédicte; Mazellier, Nicolas; Halter, Fabien; Foucher, Fabrice

    2014-01-01

    Standard particle imaging velocimetry (PIV), time-resolved particle imaging velocimetry (TR-PIV) and laser Doppler velocimetry (LDV) are complementary techniques used to measure the turbulence statistics in a fan-stirred combustion vessel. Since a solid knowledge of the aerodynamic characteristics of the turbulent flow will enable better analysis of the flame-turbulence interactions, the objective of this paper is to provide an accurate characterization of the turbulent flow inside the combustion vessel. This paper aims at becoming a reference for further work on turbulent premixed flames using this fan-stirred combustion vessel. Close approximations of homogeneous and isotropic turbulence are achieved using this setup. The integral length scales L, Taylor microscales λ and Kolmogorov length scales η, the rms velocity fluctuations and the energy spectra are investigated using PIV, TR-PIV and LDV techniques. The difficulty to reach an accurate estimation of the integral length scale is particularly examined. The strengths and limitations of these three techniques are highlighted. High temporally resolved and high spatially resolved PIV appears as an interesting alternative to LDV in so far as close attention is paid to the measurements resolution. Indeed, the largest scales of the flow are limited by the field size and the smallest ones may be not caught with high accuracy due to the limited spatial resolution. A low spatial resolution of the PIV measurements can also lead to an underestimation of the rms velocity fluctuations. As the vessel was designed to study turbulent combustion at high initial pressure and high initial temperature, the effects of the gas temperature and pressure on the energy spectra and the turbulent parameters are finally investigated in the last part of the paper.

  4. Effect of Initial Moisture Content on the in-Vessel Composting Under Air Pressure of Organic Fraction of MunicipalSolid Waste in Morocco

    Directory of Open Access Journals (Sweden)

    Abdelhadi Makan

    2013-01-01

    Full Text Available This study aimed to evaluate the effect of initial moisture content on the in-vessel composting under air pressure of organic fraction of municipal solid waste in Morocco in terms of internal temperature, produced gases quantity, organic matter conversion rate, and the quality of the final composts.For this purpose, in-vessel bioreactor was designed and used to evaluate both appropriate initial air pressure and appropriate initial moisture content for the composting process. Moreover, 5 experiments were carried out within initial moisture content of 55%, 65%, 70%, 75% and 85%. The initial air pressure and the initial moisture content of the mixture showed a significant effect on the aerobic composting. The experimental results demonstrated that for composting organic waste, relatively high moisture contents are better at achieving higher temperatures and retaining them for longer times.This study suggested that an initial moisture content of around 75%, under 0.6 bar, can be considered as being suitable for efficient composting of organic fraction of municipal solid waste. These last conditions, allowed maximum value of temperature and final composting product with good physicochemical properties as well as higher organic matter degradation and higher gas production. Moreover, final compost obtained showed good maturity levels and can be used for agricultural applications.

  5. Unibody Composite Pressurized Structure (UCPS) for In-Space Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Microcosm, in conjunction with the Scoprius Space Launch Company (SSLC), will develop a Unibody Composite Pressurized Structure (UCPS) for in-space propulsion that...

  6. Evaluation of defects induced by neutron radiation in reactor pressure vessels steels; Evaluacion de los defectos inducidos por la radiacion neutronica en los aceros de vasijas

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Jimenez, J.

    1978-07-01

    We have developed a method for calculating the production of neutron induced defects (depleted zone and crowdions) in ferritic pressure vessel steels for different neutron spectra. They have been analysed both the recoil primary atoms produced by elastic and inelastic collisions with fast neutrons and the ones produced by gamma-ray emission by thermal neutron absorption. Theoretical modelling of increasing in the ductile-brittle transition temperature of ferritic steels has been correlated with experimental data at irradiation temperature up to 400 degree centigree (Author) 15 refs.

  7. The role of water chemistry for environmentally assisted cracking in low-alloy reactor pressure vessel and piping steels under boiling reactor conditions

    Energy Technology Data Exchange (ETDEWEB)

    Seifert, H.-P.; Ritter, S

    2005-07-01

    The environmentally assisted initiation and propagation of cracks in structural materials is one of the most important degradation and ageing mechanisms in light water reactors (LWR) and may seriously affect plant availability and economics. In the first part of this paper a short general introduction on environmentally assisted cracking (EAC) and its significance for LWR is given. Then the important role of water chemistry control in reducing the EAC risk in LWR is illustrated by current research results about the effect of chloride transients and hydrogen water chemistry on the EAC crack growth behaviour of low-alloy reactor pressure vessel and piping steels under boiling water reactor conditions. (author)

  8. The use of cyclone filters to reduce the foreign matter insertion into the reactor pressure vessel; Einsatz von Zyklonabscheidern zur Verringerung eines Fremdkoerpereintrags in den Reaktordruckbehaelter

    Energy Technology Data Exchange (ETDEWEB)

    Widmann, W. [Westinghouse Electric Germany GmbH, Mannheim (Germany)

    2010-05-15

    Fuel element damage can induce a significant disturbance of the normal NPP operation. Foreign matter insertion into the reactor pressure vessel by the feed water pipes is supposed to be the main cause for fuel element damage in boiling water reactors. Vattenfall AB and Westinghouse Electric Sweden AB have developed a cyclone filter for nuclear facilities. The operational experience of cyclone filters in the feedwater line have reduced the fuel element damages significantly. Westinghouse Electric Germany is performing a feasibility study for the implementation of cyclone filter in the NPP Kruemmel.

  9. Effect of surfactants on pressure-sensitivity of CNT filled cement mortar composites

    Science.gov (United States)

    Han, Baoguo; Yu, Xun

    2014-11-01

    Sodium dodecyl sulfate (SDS) and sodium dodecylbenzene sulfonate (NaDDBS) were used as surfactants to disperse multi-walled carbon nanotubes (MWNT) in cement mortar and fabricate pressure-sensitive carbon nanotubes filled cement mortar composites. The pressure-sensitivity of cement mortar composites with different concentrations of MWNT and different surfactants was explored under repeated loading and impulsive loading, respectively. Experimental results indicate that the response of the electrical resistance of composites with NaDDBS to external force is more stable and sensitive than that of composites with SDS. Therefore, NaDDBS has higher efficiency than SDS for the dispersion of MWNT in cement mortar, and it is an effective surfactant for fabricating MWNT filled cement mortar composites with superior pressure-sensitivity.

  10. Composition and crystallinity of silicon nanoparticles synthesised by hot wire thermal catalytic pyrolysis at different pressures

    CSIR Research Space (South Africa)

    Scriba, MR

    2009-04-01

    Full Text Available The effect of pressure on the structure and composition of silicon nanoparticles synthesized by hot wire thermal catalytic pyrolysis (HW-TCP) of pure silane has been investigated. Light brown powders were produced at silane pressures of 10 and 50...

  11. Characterization of high-pressure RTM processes for manufacturing of high performance composites

    OpenAIRE

    R. Chaudhari; Karcher, M.; Elsner, P.; Henning, F

    2012-01-01

    The current paper addresses new variants of the RTM process namely High Pressure-Injection Resin Transfer Molding (HP-IRTM) and High Pressure - Compression Resin Transfer Molding (HP-CRTM) for manufacturing of continuous fiber reinforced composites with high fiber volume content. Both these process utilize High Pressure RTM equipment for precise dosing and mixing of highly reactive epoxy resin and amine hardener with relatively high throughput rates. The objective of the proposed study was to...

  12. Effect of multiparity on electrolyte composition and blood pressure ...

    African Journals Online (AJOL)

    Pregnancy affects the physiology of the pregnant woman particularly the endocrine, cardiovascular and the renal systems. This work was therefore set to ascertain the state of electrolytes in pregnancy and how it affects blood pressure using multiparity as a factor. One hundred and twenty (120) women were used in this ...

  13. The 4th surveillance test and evaluation of the reactor pressure vessel material (capsule W) of Yonggwang nuclear power plant unit 2

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Kee Ok; Kim, Byoung Chul; Lee, Sam Lai; Choi, Kwon Jae; Gong, Un Sik; Chang, Jong Hwa; Joo, Yong Sun; Ahn, Sang Bok; Hong, Joon Hwa [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2001-02-01

    Surveillance testing for reactor vessel materials is performed in order to evaluate the irradiation embrittlement due to neutrons during operation and set the condition of safe operation of nuclear reactor. The 4th surveillance testing was performed completely by Korea Atomic Energy Research Institute at Taejeon after the capsule was transported from Kori site including its removal from reactor. Fast neutron fluences for capsules were calculated and various testing including mechanical and chemistry analysis were performed in order to evaluate the integrity of Yonggwang unit 2 reactor vessel during the operation until life time. The evaluation results are as follows; Fast neutron fluences for capsules U, V, X and W are 5.762E+18, 1.5391E+19, 3.5119E+19, and 4.2610E+19 n/cm{sup 2}, respectively. The bias factor, the ratio of measurement versus calculation, was 0.899 for the 1st through 4th testing and the calculational uncertainty, 12.3% satisfied the requirement of USNRC Reg.Guide DG-1053, 20%. The best estimated neutron fluence for reactor vessel inside surface was 1.357E+19 n/cm{sup 2} based on the end of 11th fuel cycle and it was predicted that the fluences of vessel inside surface at 32, 40, 48 and 56EFPY would reach 3.525E+19, 4.337E+19, 5.148E+19 and 5.960E+19 n/cm{sup 2} based on the current calculation. The result through this analysis for Yonggwang unit 2 showed that there would be no problem for the pressurized thermal shock(PTS) during the operation until design life. 48 refs., 35 figs., 42 tabs. (Author)

  14. The 4th surveillance test and evaluation of the reactor pressure vessel material (capsule W) of Younggwang nuclear power plant unit1

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Byoung Chul; Lee, Sam Lai; Choi, Kwon Jae [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2001-08-01

    Surveillance testing for reactor vessel materials is performed in order to evaluate the irradiation embrittlement due to neutrons during operation and set the condition of safe operation of nuclear reactor. The 4th surveillance testing was performed completely by Korea Atomic Energy Research Institute at Taejeon after the capsule was transported from Yonggwang site including its removal from reactor. Fast neutron fluences for capsules were calculated and various testing including mechanical and chemistry analysis were performed in order to evaluate the integrity of Yonggwang unit 1 reactor vessel during the operation until life time. The evaluation results are as follows; Fast neutron fluences for capsules U, V, X and W are 5.555E+18, 1.662E+19, 3.358E+19, and 4.521E+19 n/cm{sup 2}, respectively. The bias factor, the ratio of measurement versus calculation, was 0.859 for the 1st through 4th testing and the calculational uncertainty, 11.80% satisfied the requirement of USNRC Reg.Guide 1.190, 20%. The best estimated neutron fluence for reactor vessel inside surface was 1.551E+19 n/cm{sup 2} based on the end of 12th fuel cycle and it was predicted that the fluences of vessel inside surface at 32, 40, 48 and 56EFPY would reach 3.929E+19, 4.880E+19, 5.831E+19 and 6.782E+19 n/cm{sup 2} based on the current calculation. The result through this analysis for Yonggwang unit 1 showed that there would be no problem for the pressurized thermal shock(PTS) during the operation until design life. 4 refs., 41 figs., 35 tabs. (Author)

  15. Development of temperature stable charge based piezoelectric composite quasi-static pressure sensors

    NARCIS (Netherlands)

    Ende, D.A. van den; Groen, W.A.; Zwaag, S. van der

    2010-01-01

    In this work piezoelectric composite charge based sensors are developed, aimed at quasi-static pressure sensor or switch type applications. The use of piezoelectric composite materials allows for manufacturing robust devices which can easily be integrated with conventional polymer processing.

  16. The behavior of high-strength unidirectional composites under tension with superposed hydrostatic pressure

    NARCIS (Netherlands)

    Zinoviev, P.A.; Tsvetkov, S.V.; Kulish, G.G.; Berg, van den R.W.; Schepdael, van L.J.M.M.

    2001-01-01

    Three types of high-strength unidirectional composite materials were studied under longitudinal tension with superposed high hydrostatic pressure. Reinforcing fibers were T1000G carbon, S2 glass and Zylon PBO fibers; the Ciba 5052 epoxy resin was used as matrix. The composites were tested under

  17. Surgical and histopathological effects of topical Ankaferd hemostat on major arterial vessel injury related to elevated intra-arterial blood pressure

    Directory of Open Access Journals (Sweden)

    A. Tulga Ulus

    2011-09-01

    Full Text Available Objective: The aim of this study was to assess the surgical and histopathological hemostatic effects of topical Ankaferd blood stopper (ABS on major arterial vessel injury related to elevated intra-arterial blood pressure in an experimental rabbit model.Materials and Methods: The study included 14 New Zealand rabbits. ABS was used to treat femoral artery puncture on 1 side in each animal and the other untreated side served as the control. Likewise, for abdominal aortic puncture, only 50% of the aortic injuries received topical liquid ABS and the others did not (control. The experiment was performed under conditions of normal arterial blood pressure and was repeated with a 50% increase in blood pressure. Histopathological analysis was performed in all of the studied animals.Results: Mean bleeding time in the control femoral arteries was 105.0±18.3 s, versus 51.4±9.8 s (p<0.05 in those treated with ABS. Mean blood loss from the punctured control femoral arteries was 5.0±1.5 mg and 1.6±0.4 mg from those treated with ABS (p<0.05. Histopathological examination of the damaged arterial structures showed that ABS induced red blood cell aggregates.Conclusion: ABS administered to experimental major arterial vessel injury reduced both bleeding time and blood loss under conditions of normal and elevated intra-arterial blood pressure. ABS-induced erythroid aggregation was prominent at the vascular tissue level. These findings will inform the design of future experimental and clinical studies on the anti-bleeding and vascular repairing effects of the novel hemostatic agent ABS.

  18. Investigation of the Effects of Submerged Arc Welding Process Parameters on the Mechanical Properties of Pressure Vessel Steel ASTM A283 Grade A

    Directory of Open Access Journals (Sweden)

    Prachya Peasura

    2017-01-01

    Full Text Available The pressure vessel steel is used in boilers and pressure vessel structure applications. This research studied the effects of submerged arc welding (SAW process parameters on the mechanical properties of this steel. The weld sample originated from ASTM A283 grade A sheet of 6.00-millimeter thickness. The welding sample was treated using SAW with the variation of three process factors. For the first factor, welding currents of 260, 270, and 280 amperes were investigated. The second factor assessed the travel speed, which was tested at both 10 and 11 millimeters/second. The third factor examined the voltage parameter, which was varied between 28 and 33 volts. Each welding condition was conducted randomly, and each condition was tested a total of three times, using full factorial design. The resulting materials were examined using tensile strength and hardness tests and were observed with optical microscopy (OM and scanning electron microscopy (SEM. The results showed that the welding current, voltage, and travel speed significantly affected the tensile strength and hardness (P value < 0.05. The optimum SAW parameters were 270 amperes, 33 volts, and 10 millimeters/second travel speed. High density and fine pearlite were discovered and resulted in increased material tensile strength and hardness.

  19. Microstructure and embrittlement of VVER 440 reactor pressure vessel steels; Microstructure et fragilisation des aciers de cuve des reacteurs nucleaires VVER 440

    Energy Technology Data Exchange (ETDEWEB)

    Hennion, A

    1999-03-15

    27 VVER 440 pressurised water reactors operate in former Soviet Union and in Eastern Europe. The pressure vessel, is made of Cr-Mo-V steel. It contains a circumferential arc weld in front of the nuclear core. This weld undergoes a high neutron flux and contains large amounts of copper and phosphorus, elements well known for their embrittlement potency under irradiation. The embrittlement kinetic of the steel is accelerated, reducing the lifetime of the reactor. In order to get informations on the microstructure and mechanical properties of these steels, base metals, HAZ, and weld metals have been characterized. The high amount of phosphorus in weld metals promotes the reverse temper embrittlement that occurs during post-weld heat treatment. The radiation damage structure has been identified by small angle neutron scattering, atomic probe, and transmission electron microscopy. Nanometer-sized clusters of solute atoms, rich in copper with almost the same characteristics as in western pressure vessels steels, and an evolution of the size distribution of vanadium carbides, which are present on dislocation structure, are observed. These defects disappear during post-irradiation tempering. As in western steels, the embrittlement is due to both hardening and reduction of interphase cohesion. The radiation damage specificity of VVER steels arises from their high amount of phosphorus and from their significant density of fine vanadium carbides. (author)

  20. Comparison of applicability of current transition temperature shift models to SA533B-1 reactor pressure vessel steel of Korean nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Ji Hyun; Lee, Bong Sang [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2017-08-15

    The precise prediction of radiation embrittlement of aged reactor pressure vessels (RPVs) is a prerequisite for the long-term operation of nuclear power plants beyond their original design life. The expiration of the operation licenses for Korean reactors the RPVs of which are made from SA533B-1 plates and welds is imminent. Korean regulatory rules have adopted the US Nuclear Regulatory Commission's transition temperature shift (TTS) models to the prediction of the embrittlement of Korean reactor pressure vessels. The applicability of the TTS model to predict the embrittlement of Korean RPVs made of SA533B-1 plates and welds was investigated in this study. It was concluded that the TTS model of 10 CFR 50.61a matched the trends of the radiation embrittlement in the SA533B-1 plates and welds better than did that of Regulatory Guide (RG) 1.99 Rev. 2. This is attributed to the fact that the prediction performance of 10 CFR 50.61a was enhanced by considering the difference in radiation embrittlement sensitivity among the different types of RPV materials.

  1. Structures of Bordered Pits Potentially Contributing to Isolation of a Refilled Vessel from Negative Xylem Pressure in Stems of Morus australis Poir.: Testing of the Pit Membrane Osmosis and Pit Valve Hypotheses.

    Science.gov (United States)

    Ooeda, Hiroki; Terashima, Ichiro; Taneda, Haruhiko

    2017-02-01

    Two hypotheses have been proposed to explain the mechanism preventing the refilling vessel water from being drained to the neighboring functional vessels under negative pressure. The pit membrane osmosis hypothesis proposes that the xylem parenchyma cells release polysaccharides that are impermeable to the intervessel pit membranes into the refilling vessel; this osmotically counteracts the negative pressure, thereby allowing the vessel to refill. The pit valve hypothesis proposes that gas trapped within intervessel bordered pits isolates the refilling vessel water from the surrounding functional vessels. Here, using the single-vessel method, we assessed these hypotheses in shoots of mulberry (Morus australis Poir.). First, we confirmed the occurrence of xylem refilling under negative pressure in the potted mulberry saplings. To examine the pit membrane osmosis hypothesis, we estimated the semi-permeability of pit membranes for molecules of various sizes and found that the pit membranes were not semi-permeable to polyethylene glycol of molecular mass osmosis mechanism in mulberry would be unrealistically large. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  2. Chemical composition of bioactive pressurized extracts of Romanian aromatic plants

    OpenAIRE

    Miron, T. L.; Plaza, Merichel; Bahrim, G.; Ibáñez, Elena; Herrero, Miguel

    2011-01-01

    In this contribution, pressurized liquid extraction (PLE) has been employed to isolate bioactive compounds from three native Romanian plants, oregano (Origanum vulgare), tarragon (Artemisia dracunculus) and wild thyme (Thymus serpyllum). Different PLE conditions have been tested including extraction with water, ethanol and their mixtures in a wide range of extraction temperatures (50–200 °C), and the antioxidant capacity of the extracts was measured using different assays (DPPH radical scaven...

  3. Electrical Pressure Transducers Based on Graphene Oxide Polysiloxane Composites

    Directory of Open Access Journals (Sweden)

    Antonio PELUSO

    2010-12-01

    Full Text Available Exfoliated graphite oxide embedded into a polysiloxane matrix can be simply obtained by sonochemical approach. These nanocomposites show an electrical conductivity depending on the applied stress and have most of crucial characteristics of an electrical pressure transducer (absence of electrical hysteresis, prompt resistivity variation, etc.. The highest sensitivity for these electrical devices is obtained with exfoliated graphene oxide concentration just a little inferior to the percolation threshold (that is, 5.5wt.% of graphene.

  4. Numerical Simulation of the Pressure Distribution in the Reactor Vessel Downcomer Region Fluctuated by the Reactor Coolant Pump

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Dong Hwa; Jung, Byung Ryul; Jang, Ho Cheol; Yune, Seok Jeong; Kim, Eun Kee [KEPCO EnC, Daejeon (Korea, Republic of)

    2015-10-15

    In this study the numerical simulation of the pressure distribution in the downcomer region resulting from the pressure pulsation by the Reactor Coolant Pump (RCP) is performed using the Finite Difference Method (FDM). Simulation is carried out for the cylindrical shaped 2-dimensional model equivalent to the outer surface of the Core Support Barrel (CSB) of APR1400 and a 1/2 model is adopted based on the bilateral symmetry by the inlet nozzle. The fluid temperature is 555 .deg. F and the forcing frequencies are 120Hz, 240Hz, 360Hz and 480Hz. Simulation results of the axial pressure distributions are provided as the Root Mean Square (RMS) values at the five locations of 0°, 45°, 90°, 135° and 180° in the circumferential direction from the inlet nozzle location. In the study, the numerical simulation of pressure distributions in the downcomer region induced by the RCP was performed using FDM and the results were reviewed. The interference of the waves returned from both boundaries in the axial direction and the source of the sinusoidal wave is shown on the inlet nozzle interface pressure point. It seems that the maximum pressures result from the superposition of the waves reflected from the seating surface and the waves newly arrived from the inlet nozzle interface pressure location.

  5. In 6- to 8-year-old children, hair cortisol is associated with body mass index and somatic complaints, but not with stress, health-related quality of life, blood pressure, retinal vessel diameters, and cardiorespiratory fitness.

    Science.gov (United States)

    Gerber, Markus; Endes, Katharina; Brand, Serge; Herrmann, Christian; Colledge, Flora; Donath, Lars; Faude, Oliver; Pühse, Uwe; Hanssen, Henner; Zahner, Lukas

    2017-02-01

    Hair cortisol measurement has become an increasingly accepted approach in endocrinology and biopsychology. However, while in adult research hair cortisol has been proposed as a relevant biomarker for chronic stress (and its adverse consequences), studies with children are scarce. Therefore, the goal of the present exploratory study was to examine the associations between hair cortisol concentrations (HCCs), stress, and a series of health-related outcomes in a sample of Swiss first grade schoolchildren. The sample consisted of 318 children (53% girls, M age =7.26, SD=0.35). Hair strands were taken near the scalp from a posterior vertex position, and HCCs were tested for the first 3-cm hair segment. Parents provided information about their children's age, gender, parental education, children's stress (recent critical life events, daily hassles), health-related quality of life, and psychosomatic complaints. Body composition, blood pressure, retinal vessel diameters, and cardiorespiratory fitness were measured with established methods. In multiple regression analyses, higher HCCs were weakly associated with increased BMI in girls (β=0.22, p<0.001), whereas higher HCCs were associated with increased somatic complaints in boys (β=0.20, p<0.05). No significant relationships were found between HCCs and parental reports of stress, health-related quality of life, blood pressure, retinal vessel diameters, and cardiorespiratory fitness. Although small significant relationships were found between HCCs, BMI and somatic complaints, the findings of this exploratory study challenge the view that HCCs can be used as a reliable biomarker of recent critical life events, daily hassles, health-related quality of life, and cardiovascular health indicators in non-clinical young children. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Triple rotary gas lock seal system for transferring coal continuously into, or ash out of, a pressurized process vessel

    Energy Technology Data Exchange (ETDEWEB)

    Enright, F.J.; Seidl, R.M.

    1981-01-13

    A multiple rotary gas lock apparatus using a buffer seal gas is disclosed to enable the transfer of solid materials into or out of a pressurized process containing high temperature, flammable or toxic gases. The buffer seal gas, has a pressure higher than the process pressure and is introduced between two series connected gas locks; this prevents process gas backflow to the feed system. Buffer seal leakage gas from the first pair of gas locks and air from a third gas lock are removed from an opening in a connection between the pair of gas locks and the third gas lock at subatmospheric pressure. This system enables control and usuage of toxic or flammable gases as a buffer for mixing compatibility with the process gas when a suitable inert gas is not available. It also prevents the flow of any toxic gas to the worker environment.

  7. Fluorescent Pressure Response of Protein-Nanocluster Polymer Composites

    Science.gov (United States)

    2016-05-01

    Program at the US Army Research Laboratory (ARL) administered by the Oak Ridge Institute for Science and Education through an interagency agreement...nanoclusters exhibit fluorescent effects similarly to semiconductor-based quantum dots and are not nearly as toxic due to their lack of heavy metals.7...in the range of 300–500 psig [2.07–3.44 MPa] on the brain). Generally, pressures above 200 psig (1.38 MPa) cause fatality and 29–75 psig (0.2– 0.52

  8. Asphaltene laboratory assessment of a heavy onshore reservoir during pressure, temperature and composition variations to predict asphaltene onset pressure

    Energy Technology Data Exchange (ETDEWEB)

    Bahrami, Peyman; Ahmadi, Yaser [Islamic Azad University, Tehran (Iran, Islamic Republic of); Kharrat, Riyaz [Petroleum University of Technology, Tehran (Iran, Islamic Republic of); Mahdavi, Sedigheh; James, Lesley [Memorial University of Newfoundland, Saint John' s (Canada)

    2015-02-15

    An Iranian heavy oil reservoir recently encountered challenges in oil production rate, and further investigation has proven that asphaltene precipitation was the root cause of this problem. In addition, CO{sub 2} gas injection could be an appropriate remedy to enhance the production of heavy crudes. In this study, high pressure-high temperature asphaltene precipitation experiments were performed at different temperatures and pressures to investigate the asphaltene phase behavior during the natural depletion process and CO{sub 2} gas injection. Compositional modeling of experimental data predicted onset points at different temperatures which determine the zone of maximum probability of asphaltene precipitation for the studied heavy oil reservoir. Also, the effect of CO{sub 2} gas injection was investigated as a function of CO{sub 2} concentration and pressure. It was found that a CO{sub 2}-oil ratio of 40% is the optimum for limiting precipitation to have the least formation damage and surface instrument contamination.

  9. A study on measurements of local ice pressure for ice breaking research vessel “ARAON” at the Amundsen Sea

    Directory of Open Access Journals (Sweden)

    Yong-Hyeon Kwon

    2015-05-01

    Full Text Available In this study, a local ice pressure prediction has been conducted by using measured data from two ice breaking tests that was conducted for a relatively big ice floe at Amundsen Sea in the Antarctica from January 31 to March 30 2012. The symmetry of load was considered by attaching strain gauges on the same sites inside the shell plating of ship at the port and the starboard sides in the bow thrust room. Using measured strain data, after the ice pressure was converted by the influence coefficient method and the direct method, the two values were found to be similar.

  10. Significance of Shrinkage Induced Clamping Pressure in Fiber-Matrix Bonding in Cementitious Composite Materials

    DEFF Research Database (Denmark)

    Stang, Henrik

    1996-01-01

    inhomogeneity embedded in a matrix consisting of acementitious material undergoing shrinkage during hydration(autogenous shrinkage). Furthermore, the paperpresents the analysis necessary to perform an interpretation of the experimental results and which allows for thedetermination of the clamping pressure......The present paper accesses the significance of shrinkage inducedclamping pressure in fiber/matrix bonding mechanisms incementitious composite materials. The paper contains a description of an experimental setup whichallows mbox{measurement} of the clamping pressure which develops on anelastic...... acting on any elastic inhomogeneityembedded in the same cementitious matrix material. Fiber-shaped inhomogeneities are of special interest in cementitious composite material systems andresults are presented for the development of clamping pressure on three typical fiber types in two typical cementpastes...

  11. Development of a methodology for the assessment of shallow-flaw fracture in nuclear reactor pressure vessels: Generation of biaxial shallow-flaw fracture toughness data

    Energy Technology Data Exchange (ETDEWEB)

    McAfee, W.J.; Bass, B.R.; Bryson, J.W.

    1998-07-01

    A technology to determine shallow-flaw fracture toughness of reactor pressure vessel (RPV) steels is being developed for application to the safety assessment of RPVs containing postulated shallow-surface flaws. Shallow-flaw fracture toughness of RPV material has been shown to be higher than that for deep flaws, because of the relaxation of crack-tip constraint. This report describes the preliminary test results for a series of cruciform specimens with a uniform depth surface flaw. These specimens are all of the same size with the same depth flaw. Temperature and biaxial load ratio are the independent variables. These tests demonstrated that biaxial loading could have a pronounced effect on shallow-flaw fracture toughness in the lower transition temperature region for RPV materials. Through that temperature range, the effect of full biaxial (1:1) loading on uniaxial, shallow-flaw toughness varied from no effect near the lower shelf to a reduction of approximately 58% at higher temperatures.

  12. Study of atomic clusters in neutron irradiated reactor pressure vessel surveillance samples by extended X-ray absorption fine structure spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Cammelli, S. [LWV, NES, Paul Scherrer Institute, 5232 Villigen PSI (Switzerland); Fachbereich C - Physik, Bergische Universitaet Wuppertal, Gauss-Str. 20, 42097 Wuppertal (Germany)], E-mail: Sebastiano.cammelli@psi.ch; Degueldre, C.; Kuri, G.; Bertsch, J. [LWV, NES, Paul Scherrer Institute, 5232 Villigen PSI (Switzerland); Luetzenkirchen-Hecht, D.; Frahm, R. [Fachbereich C - Physik, Bergische Universitaet Wuppertal, Gauss-Str. 20, 42097 Wuppertal (Germany)

    2009-03-31

    Copper and nickel impurities in nuclear reactor pressure vessel (RPV) steel can form nano-clusters, which have a strong impact on the ductile-brittle transition temperature of the material. Thus, for control purposes and simulation of long irradiation times, surveillance samples are submitted to enhanced neutron irradiation. In this work, surveillance samples from a Swiss nuclear power plant were investigated by extended X-ray absorption fine structure spectroscopy (EXAFS). The density of Cu and Ni atoms determined in the first and second shells around the absorber is affected by the irradiation and temperature. The comparison of the EXAFS data at Cu and Ni K-edges shows that these elements reside in arrangements similar to bcc Fe. However, the EXAFS analysis reveals local irradiation damage in the form of vacancy fractions, which can be determined with a precision of {approx}5%. There are indications that the formation of Cu and Ni clusters differs significantly.

  13. The application of mechanical and thermal cutting tools for the dismantling of activated internals of the reactor pressure vessels in the Versuchsatomkraftwerk, Kahl and the Gundremmingen Unit A

    Energy Technology Data Exchange (ETDEWEB)

    Eickelpasch, N. [Versuchsatomkraftwerk GmbH, Kahl am Main (Germany); Kalwa, H. [Versuchsatomkraftwerk GmbH, Kahl am Main (Germany); Steiner, H. [Kernkraftwerke Gundremmingen Betriebsgesellschaft mbH, D-89355 Gundremmingen (Germany); Priesmeyer, U. [Kernkraftwerke Gundremmingen Betriebsgesellschaft mbH, D-89355 Gundremmingen (Germany)

    1997-07-01

    The Gundremmingen Unit A plant (KRB A) and the Versuchsatomkraftwerk Kahl (VAK) plant represent the first generation of nuclear reactors in Germany. The 250 MW{sub e} reactor KRB A was the first commercial reactor in Germany and the 16 MW{sub e} reactor VAK was the pilot nuclear power plant, which had to serve mainly scientific purposes. KRB A is under dismantling since 1983, VAK since 1988. Although they are both of the boiling water type, they are rather different to each other, referring to their size and construction. The actual work is the dismantling of high contaminated components inside the reactor buildings and the underwater cutting of activated internals of the reactor pressure vessels. Several cutting techniques have been developed, tested and applied to respective dismantling tasks in the meantime. The experiences made in both projects are not limited to dismantling work only, but also include know-how on effective decontamination and scrap recycling. (orig.)

  14. Experience gathered in dismounting pressure vessel internals of the Kahl experimental reactor (VAK Kahl); Erfahrungen bei der Zerlegung der Druckgefaesseinbauten im VAK Kahl

    Energy Technology Data Exchange (ETDEWEB)

    Kalwa, H. [Versuchsatomkraftwerk Kahl GmbH, Karlstein am Main (Germany); Eickelpasch, N. [Versuchsatomkraftwerk Kahl GmbH, Karlstein am Main (Germany); Reiter, W. [Versuchsatomkraftwerk Kahl GmbH, Karlstein am Main (Germany)

    1995-11-01

    Mechanical cutting processes are preferred for dismantling of activated pressure vessel internals in the VAK Kahl. Up to now, sawing, nibbling, grinding and electroeroding have been tried. For a realistic under-water trial run on a scale of 1:1, an inactive experimental facility was erected in the empty turbine building of the VAK. (orig./DG) [Deutsch] Bei der Zerlegung der aktivierten RDB-Einbauten im Versuchsatomkraftwerk Kahl werden bevorzugt mechanische Trennverfahren angewendet. Erprobt und eingesetzt wurden bisher das Saegen, das Knabbern, das Schleifen und das Elektroerodieren. Fuer eine realitaetsnahe Erprobung unter Wasser im Massstab 1:1 wurde in VAK ein inaktiver Versuchsstand im bereits leergeraeumten Maschinenhaus erstellt. (orig./DG)

  15. Sensitivity of hydrodynamic parameters' distributions in VVER-1000 reactor pressure vessel (RPV) with respect to uncertainty of the local hydraulic resistance coefficients

    Energy Technology Data Exchange (ETDEWEB)

    Pasichnyk, I.; Velkov, K. [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH, Garching (Germany); Nikonov, S. [NRC ' ' Kurchatov Institute' ' , Moscow (Russian Federation)

    2014-08-15

    The paper presents an uncertainty and sensitivity (U and S) study of the VVER-1000 reactor hydraulic properties. It is based on the OECD/NEA coolant transient Benchmark (K-3) on measured data at Kalinin-3 Nuclear Power Plant (NPP). The novelty of the work consists of taking into consideration all hydraulic uncertainty parameters used in the modeling of the reactor pressure vessel (RPV) internals. A detailed parallel channel ATHLET model of the RPV is developed. It consists of ca. 26 600 control volumes most of them connected with junctions for cross flows. The specific geometry of the gap between upper part of the baffle and upper part of fuel assembly and also a fuel assembly head is taken explicitly into account The influence of the input parameters on the sensitivity and uncertainty of the RPV outlet and inlet temperatures and mass flows as well assembly-wise mass flow and coolant temperature axial distributions is shown.

  16. The Assessment and Validation of Mini-Compact Tension Test Specimen Geometry and Progress in Establishing Technique for Fracture Toughness Master Curves for Reactor Pressure Vessel Steels

    Energy Technology Data Exchange (ETDEWEB)

    Sokolov, Mikhail A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Nanstad, Randy K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-01

    Small specimens are playing the key role in evaluating properties of irradiated materials. The use of small specimens provides several advantages. Typically, only a small volume of material can be irradiated in a reactor at desirable conditions in terms of temperature, neutron flux, and neutron dose. A small volume of irradiated material may also allow for easier handling of specimens. Smaller specimens reduce the amount of radioactive material, minimizing personnel exposures and waste disposal. However, use of small specimens imposes a variety of challenges as well. These challenges are associated with proper accounting for size effects and transferability of small specimen data to the real structures of interest. Any fracture toughness specimen that can be made out of the broken halves of standard Charpy specimens may have exceptional utility for evaluation of reactor pressure vessels (RPVs) since it would allow one to determine and monitor directly actual fracture toughness instead of requiring indirect predictions using correlations established with impact data. The Charpy V-notch specimen is the most commonly used specimen geometry in surveillance programs. Assessment and validation of mini-CT specimen geometry has been performed on previously well characterized HSST Plate 13B, an A533B class 1 steel. It was shown that the fracture toughness transition temperature measured by these Mini-CT specimens is within the range of To values that were derived from various large fracture toughness specimens. Moreover, the scatter of the fracture toughness values measured by Mini-CT specimens perfectly follows the Weibull distribution function providing additional proof for validation of this geometry for the Master Curve evaluation of rector pressure vessel steels. Moreover, the International collaborative program has been developed to extend the assessment and validation efforts to irradiated weld metal. The program is underway and involves ORNL, CRIEPI, and EPRI.

  17. Scoping Experiments for Pressure Drop Measurement for the Ex-Vessel Debris Bed Coolability in Severe Accidents

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jin Ho; Kim, Eun Ho; Park, Hyun Sun [POSTECH, Pohang (Korea, Republic of); Kim, Moo Hwan [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of); Ma, Weimin; Bechta, Sevostian [Nuclear Power Safety Division, Stockholm (Sweden)

    2014-05-15

    To ensure the long-term cooling of corium in the reactor cavity, it is important to ensure the coolant ingression into the internally heat generated corium debris bed governed by pressure drop in the porous media. According to the previous investigations on molten fuel-coolant interactions (FCIs) experiments, the debris beds are expected to form channels in the bed due to intensive boiling and flow. And also, it was found that quenched particulate debris bed was composed of multi-sized (0∼10 mm), irregular shape particles and it has a micro/macro inhomogeneity such as axially and radially stratified debris bed, where a layer of smaller particles covers the main bed part. In this particulate debris bed with the internal heat generation by decay heat, not only co- but also counter-current two-phase flow may be occurred by the water inflow through sides of bed combined with steam outflow to top of bed. To investigate the effect of each characteristics of heterogeneous debris bed expected in real severe accident scenarios on pressure drop with various conditions, an experimental facility called as PICASSO (Pressure drop Investigation and Coolability ASSessment through Observation) facility was constructed. With the experimental facility, the scoping test was conducted as injecting upward air flow into the bottom of particle bed composed of 2 mm, 5 mm spherical SUJ-2 balls respectively, and the experimental data compared with Ergun equation. As a result of the single phase flow experiment using air, Ergun equation predicts the experimental data for the spherical particles with the diameter of 2 mm and 5 mm with a mean deviation of 14.62 %.

  18. A lower limit of atmospheric pressure on early Mars inferred from nitrogen and argon isotopic compositions

    Science.gov (United States)

    Kurokawa, Hiroyuki; Kurosawa, Kosuke; Usui, Tomohiro

    2018-01-01

    We examine the history of the loss and replenishment of the Martian atmosphere using elemental and isotopic compositions of nitrogen and noble gases. The evolution of the atmosphere is calculated by taking into consideration various processes: impact erosion and replenishment by asteroids and comets, atmospheric escape induced by solar radiation and wind, volcanic degassing, and gas deposition by interplanetary dust particles. Our model reproduces the elemental and isotopic compositions of N and noble gases (except for Xe) in the Martian atmosphere, as inferred from exploration missions and analyses of Martian meteorites. Other processes such as ionization-induced fractionation, which are not included in our model, are likely to make a large contribution in producing the current Xe isotope composition. Since intense impacts during the heavy bombardment period greatly affect the atmospheric mass, the atmospheric pressure evolves stochastically. Whereas a dense atmosphere preserves primitive isotopic compositions, a thin atmosphere on early Mars is severely influenced by stochastic impact events and following escape-induced fractionation. The onset of fractionation following the decrease in atmospheric pressure is explained by shorter timescales of isotopic fractionation under a lower atmospheric pressure. The comparison of our numerical results with the less fractionated N (15N/14N) and Ar (38Ar/36Ar) isotope compositions of the ancient atmosphere recorded in the Martian meteorite Allan Hills 84001 provides a lower limit of the atmospheric pressure in 4 Ga to preserve the primitive isotopic compositions. We conclude that the atmospheric pressure was higher than approximately 0.5 bar at 4 Ga.

  19. Influence of Large Intraocular Pressure Reduction on Peripapillary OCT Vessel Density in Ocular Hypertensive and Glaucoma Eyes.

    Science.gov (United States)

    Holló, Gábor

    2017-01-01

    Optical coherence tomography (OCT) angiography is a new noninvasive method to measure peripapillary microcirculation in various retinal layers, separately. In this case series, we investigate whether large medical intraocular pressure (IOP) reduction (>50% of the untreated baseline value) to IOP≤18 mm Hg influences peripapillary angioflow density (PAFD, percentage of the analyzed retinal area) in the retinal nerve fiber layer in high pressure (IOP≥35 mm Hg) ocular hypertensive and glaucoma eyes. The AngioVue OCT (software version 2015.100.0.33) was used for PAFD measurements in 6 eyes of 4 consecutive newly detected young patients (age: 32 to 45 y; 2 ocular hypertensive and 4 pigment dispersion/glaucoma eyes). PAFD was measured on high quality images (signal strength index >50) at untreated baseline and 2 to 4 weeks later when the IOP was medically reduced. The PAFD measurements were immediately followed by IOP measurements. Untreated and under treatment IOP ranged between 35 and 42 mm Hg, and 12 and 18 mm Hg, respectively (IOP decrease >50% in all cases). Peripapillary PAFD increased in all cases, in 5 cases the increase was greater than the baseline value plus 2 test-retest variability determined earlier by us on glaucoma eyes. The results suggest that large medical IOP reduction may result in clinically significant increase of peripapillary capillary perfusion in the retinal nerve fiber layer in young individuals with high untreated IOP. To evaluate the clinical usefulness of OCT angiography in the management of glaucoma detailed prospective clinical studies are necessary.

  20. Three-term Asymptotic Stress Field Expansion for Analysis of Surface Cracked Elbows in Nuclear Pressure Vessels

    Science.gov (United States)

    Labbe, Fernando

    2007-04-01

    Elbows with a shallow surface cracks in nuclear pressure pipes have been recognized as a major origin of potential catastrophic failures. Crack assessment is normally performed by using the J-integral approach. Although this one-parameter-based approach is useful to predict the ductile crack onset, it depends strongly on specimen geometry or constraint level. When a shallow crack exists (depth crack-to-thickness wall ratio less than 0.2) and/or a fully plastic condition develops around the crack, the J-integral alone does not describe completely the crack-tip stress field. In this paper, we report on the use of a three-term asymptotic expansion, referred to as the J- A 2 methodology, for modeling the elastic-plastic stress field around a three-dimensional shallow surface crack in an elbow subjected to internal pressure and out-of-plane bending. The material, an A 516 Gr. 70 steel, used in the nuclear industry, was modeled with a Ramberg-Osgood power law and flow theory of plasticity. A finite deformation theory was included to account for the highly nonlinear behavior around the crack tip. Numerical finite element results were used to calculate a second fracture parameter A 2 for the J- A 2 methodology. We found that the used three-term asymptotic expansion accurately describes the stress field around the considered three-dimensional shallow surface crack.

  1. Ductile-Brittle Transition Behavior in Tempered Martensitic SA508 Gr. 4N Ni-Mo-Cr Low Alloy Steels for Reactor Pressure Vessels

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ki Hyoung; Wee, Dang Moon [KAIST, Daejeon (Korea, Republic of); Kim, Min Chul; Lee, Bong Sang [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2010-05-15

    Reactor pressure vessels (RPVs) operate under severe conditions of elevated temperature, high pressure, and irradiation. Therefore, a combination of sufficient strength, toughness, good weldability, and high irradiation resistance are required for RPV materials. SA508 Gr.4N low alloy steel, which has higher Ni and Cr contents than those of commercial RPV steel, Gr.3 steel, is considered as a candidate material due to its excellent mechanical properties from tempered martensitic microstructure. The ferritic steels such as Gr.3 and Gr.4N low alloy steels reveal a ductile-brittle transition and large scatters in the fracture toughness within a small temperature range. Recently, there are some observations of the steeper transition behavior in the tempered martensitic steels, such as Eurofer97 than the transition behavior of commercial RPV steels. It was also reported that the fracture toughness increased discontinuously when the phase fraction of the tempered martensite was over a critical fraction in the heat affected zones of SA508 Gr.3. Therefore, it may be necessary to evaluate the changes of transition behavior with a microstructure for the tempered martensitic SA508 Gr.4N low alloy steel. In this study, the fracture toughness for SA508 Gr.4N low alloy steels was evaluated from a view point of the temperature dependency with phase fraction of tempered martensite controlled by cooling rate. Additionally, a possible modification of the fracture toughness master curve was proposed and discussed

  2. Annealing for plant life management: hardness, tensile and Charpy toughness properties of irradiated, annealed and re-irradiated mock-up low alloy nuclear pressure vessel steel

    Energy Technology Data Exchange (ETDEWEB)

    Tipping, Philip; Cripps, Robin (Paul Scherrer Inst. (PSI), Villigen (Switzerland))

    1994-01-01

    Hardness, tensile and Charpy properties of an irradiated (I) and irradiated-annealed-reirradiated (IAR) mock-up pressure vessel steel are presented. Spectrum tailored pressurized light water reactor (PWR) irradiation at 290[sup o]C by fast neutrons up to nominal fluences of 5 x 10[sup 19]/cm[sup 2] (E [>=] 1 MeV) in a swimming pool type reactor caused the hardness, tensile yield stress and tensile strength to increase. Embrittlement also occurred as indicated by Charpy toughness tests. The optimum annealing heat treatment for the main program was determined using isochronal and isothermal runs on the material and measuring the Vickers microhardness. The response to an intermediate annealing treatment (460[sup o]C for 18 h), when 50% of the target fluence has been reached and then irradiating to the required end fluence (IAR condition) was then monitored further by Charpy and tensile mechanical properties. Annealing was beneficial in mitigating overall hardening or embrittlement effects. The rate of re-embrittlement after annealing and re-irradiating was no faster than when no annealing had been performed. Annealing temperatures below 440[sup o]C were indicated as requiring relatively long times, i.e. [>=] 168 h to achieve some reduction in radiation induced hardness for example. (Author).

  3. A Review of the Application of Rate Theory to Simulate Vacancy Cluster Formation and Interstitial Defect Formation in Reactor Pressure Vessel Steel

    Directory of Open Access Journals (Sweden)

    Fallon Laliberte

    2015-10-01

    Full Text Available The beltline region of the reactor pressure vessel (RPV is subject to an extreme radiation, temperature, and pressure environment over several decades of operation; therefore it is necessary to understand the mechanisms through which radiation damage occurs and how it affects the mechanical and chemical properties of the RPV steel. Chemical rate theory is a mean field rate theory simulation model which applies chemistry to the evaluation of irradiation-induced embrittlement. It presents one method of analysis that may be coupled to other distinct methods, in order to analyze defect formation, ultimately providing useful information on strength, ductility, toughness and dimensional stability changes for effects such as embrittlement, reduction in ductility and toughness, void swelling, hardening, irradiation creep, stress corrosion cracking, etc. over time as materials are subjected to reactor operational irradiation. This paper serves as a brief review of rate theory fundamentals and presents several examples of research that exemplify the application and importance of rate theory in examining the effects of radiation damage on RPV steel.

  4. J-R Fracture Resistance of SA533 Gr.B-Cl.1 Steel for Reactor Pressure Vessel

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Ji-Hyun; Hong, Seokmin; Lee, Bong-Sang [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    A rolled plate might show different mechanical behaviors from a forging, even though they contain same chemical compositions. Furthermore, it is known that the fracture behavior of a rolled plate is very sensitive to material orientation comparing to a forging. In this study, the J-R fracture resistances of SA533 Gr.B-Cl.1 plate were measured at reactor operating temperature and the material orientation sensitivity was discussed. The decrease of fracture resistance of this kind of low alloy steel at an elevated temperature is known as the effect of dynamic strain aging (DSA). It was attributed to that the carbides and grains elongated to primary rolling direction, so that the aspect ratio of carbides and grains in the specimen with T-L orientation is larger. Generally, the hard second phase could take a roll of trigger point of unstable fracture. It is needed that the fracture surfaces of the tested specimens to be examined profoundly.

  5. The compositional variation of synthetic sodic amphiboles at high and ultra-high pressures

    Science.gov (United States)

    Tropper, P.; Manning, C. E.; Essene, E. J.; Kao, L.-S.

    Sodic amphiboles in high pressure and ultra-high pressure (UHP) metamorphic rocks are complex solid solutions in the system Na2O-MgO-Al2O3-SiO2-H2O (NMASH) whose compositions vary with pressure and temperature. We conducted piston-cylinder experiments at 20-30kbar and 700-800°C to investigate the stability and compositional variations of sodic amphiboles, based on the reaction glaucophane=2jadeite+talc, by using the starting assemblage of natural glaucophane, talc and quartz, with synthetic jadeite. A close approach to equilibrium was achieved by performing compositional reversals, by evaluating compositional changes with time, and by suppressing the formation of Na-phyllosilicates. STEM observations show that the abundance of wide-chain structures in the synthetic amphiboles is low. An important feature of sodic amphibole in the NMASH system is that the assemblage jadeite-talc+/-quartz does not fix its composition at glaucophane. This is because other amphibole species such as cummingtonite (Cm), nyböite (Nyb), Al-Na-cummingtonite (Al-Na-Cm) and sodium anthophyllite (Na-Anth) are also buffered via the model reactions: 3cummingtonite+4quartz+4H2O=7talc, nyböite+3quartz=3jadeite+talc, 3Al-Na-cummingtonite + 11quartz + 2H2O=6jadeite + 5talc, and 3 sodium anthophyllite+13quartz+4H2O=3 jadeite + 7talc. We observed that at all pressures and temperatures investigated, the compositions of newly grown amphiboles deviate significantly from stoichiometric glaucophane due to varying substitutions of AlIV for Si, Mg on the M(4) site, and Na on the A-site. The deviation can be described chiefly by two compositional vectors: [NaAAlIV][□ASi] (edenite) toward nyböite, and [Na(M4)AlVI][Mg(M4)MgVI] toward cummingtonite. The extent of nyböite and cummingtonite substitution increases with temperature and decreases with pressure in the experiments. Similar compositional variations occur in sodic amphiboles from UHP rocks. The experimentally calibrated compositional changes

  6. Pressure variation assisted fiber extraction and development of high performance natural fiber composites and nanocomposites

    Science.gov (United States)

    Markevicius, Gediminas

    It is believed, that due to the large surface areas provided by the nano scale materials, various composite properties could be enhanced when such particles are incorporated into a polymer matrix. There is also a trend of utilizing natural resources or reusing and recycling materials that are already available for the fabrication of the new composite materials. Cellulose is the most abundant natural polymer on the planet, and therefore it is not surprising to be of interest for composite fabrication. Basic structures of cellulose, comprised of long polysaccharide chains, are the building blocks of cellulose nano fibers. Nano fibers are further bound into micro fibrils and macro fibers. Theoretically pure cellulose nano fibers have tremendous strengths, and therefore are some of the most sought after nano particles. The fiber extraction however is a complex task. The ultrasound, which creates pressure variation in the medium, was employed to extract nano-size cellulose particles from microcrystalline cellulose (MCC). The length and the intensity of the cavitations were evaluated. Electron microscopy studies revealed that cellulose nanoparticles were successfully obtained from the MCC after ultrasound treatment of just 30 minutes. Structure of the fractionated cellulose was also analyzed with the help of X-ray diffraction, and its thermal properties were evaluated with the help of differential scanning calorimetry (DSC). Ultrasound treatment performed on the wheat straw, kenaf, and miscanthus particles altered fiber structure as a result of the cavitation. The micro fibers were generated from these materials after they were subjected to NaOH treatment followed by the ultrasound processing. The potential of larger than nano-sized natural fibers to be used for composite fabrication was also explored. The agricultural byproducts, such as wheat or rice straw, as well as other fast growing crops as miscanthus or kenaf, are comprised of three basic polymers. Just like in

  7. Radiation Damage Assessment in the Reactor Pressure Vessel of the Integral Inherently Safe Light Water Reactor (I2S-LWR

    Directory of Open Access Journals (Sweden)

    Flaspoehler Timothy

    2016-01-01

    Full Text Available One of the major limiting factors to nuclear reactors lifetime is the radiation-induced material damage in the Reactor Pressure Vessel (RPV. While older reactors were designed assuming a 40-year operating lifetime, new reactor designs are expected to have lifetimes up to 100 years. For safe operation, the integrity of the RPV must be ensured against significant material property changes. In this work, typical neutron damage indicators are calculated in the RPV of the I2S-LWR (Integral Inherently Safe LWR Power Plant, including DPA (displacements per atom and fast neutron fluence (>1 MeV and >0.1MeV. I2S-LWR is a PWR of integral design, which means that its wider downcomer provides additional shielding to the vessel. However, its higher core power density and longer lifetime may offset this advantage. In order to accurately represent the neutron environment for RPV damage assessment, a detailed model based on the preliminary design specifications of the I2S-LWR was developed to be used in the MAVRIC (Monaco with Automated Variance Reduction using Importance Calculations sequence of the Scale6.1 code package. MAVRIC uses the CADIS (Consistent Adjoint-Driven Importance Sampling methodology to bias a fixed-source MC (Monte Carlo simulation. To establish the upper limit of a bounding envelope, a flat-source distribution was used. For the low limit, a center-peaked source was generated using the KENO-VI criticality sequence assuming uniform fresh fuel core. Results based on the preliminary I2S-LWR model show that DPA rates and fast fluence rates are conservatively 75% lower than in typical PWRs being operated currently in the US.

  8. Radiation Damage Assessment in the Reactor Pressure Vessel of the Integral Inherently Safe Light Water Reactor (I2S-LWR)

    Science.gov (United States)

    Flaspoehler, Timothy; Petrovic, Bojan

    2016-02-01

    One of the major limiting factors to nuclear reactors lifetime is the radiation-induced material damage in the Reactor Pressure Vessel (RPV). While older reactors were designed assuming a 40-year operating lifetime, new reactor designs are expected to have lifetimes up to 100 years. For safe operation, the integrity of the RPV must be ensured against significant material property changes. In this work, typical neutron damage indicators are calculated in the RPV of the I2S-LWR (Integral Inherently Safe LWR) Power Plant, including DPA (displacements per atom) and fast neutron fluence (>1 MeV and >0.1MeV). I2S-LWR is a PWR of integral design, which means that its wider downcomer provides additional shielding to the vessel. However, its higher core power density and longer lifetime may offset this advantage. In order to accurately represent the neutron environment for RPV damage assessment, a detailed model based on the preliminary design specifications of the I2S-LWR was developed to be used in the MAVRIC (Monaco with Automated Variance Reduction using Importance Calculations) sequence of the Scale6.1 code package. MAVRIC uses the CADIS (Consistent Adjoint-Driven Importance Sampling) methodology to bias a fixed-source MC (Monte Carlo) simulation. To establish the upper limit of a bounding envelope, a flat-source distribution was used. For the low limit, a center-peaked source was generated using the KENO-VI criticality sequence assuming uniform fresh fuel core. Results based on the preliminary I2S-LWR model show that DPA rates and fast fluence rates are conservatively 75% lower than in typical PWRs being operated currently in the US.

  9. Particle Imaging Velocimetry Technique Development for Laboratory Measurement of Fracture Flow Inside a Pressure Vessel Using Neutron Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Polsky, Yarom [ORNL; Bingham, Philip R [ORNL; Bilheux, Hassina Z [ORNL; Carmichael, Justin R [ORNL

    2015-01-01

    This paper will describe recent progress made in developing neutron imaging based particle imaging velocimetry techniques for visualizing and quantifying flow structure through a high pressure flow cell with high temperature capability (up to 350 degrees C). This experimental capability has great potential for improving the understanding of flow through fractured systems in applications such as enhanced geothermal systems (EGS). For example, flow structure measurement can be used to develop and validate single phase flow models used for simulation, experimentally identify critical transition regions and their dependence on fracture features such as surface roughness, and study multiphase fluid behavior within fractured systems. The developed method involves the controlled injection of a high contrast fluid into a water flow stream to produce droplets that can be tracked using neutron radiography. A description of the experimental setup will be provided along with an overview of the algorithms used to automatically track droplets and relate them to the velocity gradient in the flow stream. Experimental results will be reported along with volume of fluids based simulation techniques used to model observed flow.

  10. Evaluation on the Feasibility of Using Ultrasonic Testing of Reactor Pressure Vessel Welds for Assessing Flaw Density/Distribution per 10 CFR 50.61a, Alternate Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, Edmund J.; Anderson, Michael T.

    2014-06-10

    This technical letter report provides the status of an assessment undertaken by PNNL at the request of the NRC to verify the capability of periodic ASME-required volumetric examinations of reactor vessels to characterize the density and distribution of flaws of interest for applying §50.61a on a plant-by-plant basis. The PTS rule, described in the Code of Federal Regulations, Title 10, Section 50.61 (§50.61), "Fracture Toughness Requirements for Protection against Pressurized Thermal Shock Events," establishes screening criteria to ensure that the potential for a reactor vessel to fail due to a PTS event is deemed to be acceptably low. Recently, the NRC completed a research program that concluded that the risk of through-wall cracking due to a PTS event is much lower than previously estimated. The NRC subsequently developed and promulgated an alternate PTS rule, §50.61a, that can be implemented by PWR licensees. The §50.61a rule differs from §50.61 in that it requires licensees who choose to follow this alternate method to analyze the results from periodic volumetric examinations required by the ASME Code, Section XI, Rules for Inservice Inspection (ISI) of Nuclear Power Plants.

  11. Critical closing pressure in the fetal vessel of the human placenta in vitro. II. Compared effects of a beta adrenergic substance, Salbutamol, on the critical closing pressure and vascular resistance.

    Science.gov (United States)

    Benedetti, W L; González-Panizza, V H; Alvarez, H

    1976-01-01

    Salbutamol effects upon the fetal vessels of the human placenta were studied in vitro, comparing the changes induced upon the critical closing pressure (CCP) and viscous resistance (R). Four normal full-term placentas were used. In each of them, 4 cotyledonary areas were perfused, thus obtaining a total of 16 measurements for the observation of spontaneous variations (blank), by perfusion with Krebs solution, and the same amount for the variations due to Salbutamol. The concentration used was 10 microgram/ml, with a 4.25 ml/min flow. The relative effect of Salbutamol upon CCP was its decrease--30.4% against a relative spontaneous variation of --3.6%. The mean relative effect upon R was much lower, --9.4%. against a mean relative spontaneous variation of + 3.3%. The advantages of using CCP instead of R as a parameter of vascular contractility are discussed. Furthermore, Salbutamol is suggested to be useful in improving fetal placental circulation.

  12. Use of Zircaloy 4 material for the pressure vessels of hot and cold neutron sources and beam tubes for research reactors

    Energy Technology Data Exchange (ETDEWEB)

    Gutsmiedl, Erwin [Technical University Munich, FRM-II (Germany)

    2001-03-01

    The material Zircaloy 4 can be used for the pressure retaining walls for the cold and hot neutron sources and beam tubes. For the research reactor FRM-II of the Technical University Munich, Germany, the material Zircaloy 4 were chosen for the vessels of the cold and hot neutron source and for the beam tube No. 6. The sheets and forgings of Zircaloy 4 were examinated in the temperature range between -256degC and 250degC. The thickness of the sheets are 3, 4, 5 and 10 mm, the maximum diameter of the forgings was 560 mm. This great forging diameters are not be treated in the ASTM rule B 351 for nuclear material, so a special approval with independent experts was necessary. The requirements for the material examinations were specified in a material specification and material test sheets which based on the ASTM rules B 351 and B 352 with additional restriction and additional requirements of the basic safety concept for nuclear power plants in Germany, which was taken into consideration in the nuclear licensing procedure. Charpy-V samples were carried out in the temperature range between -256degC and 150degC to get more information on the ductile behaviour of the Zircaloy 4. The results of the sheet examination confirm the requirements of the specifications, the results of the forging examination in the tangential testing direction are lower than specified and expected for the tensile strength. The axial and transverse values confirm the specification requirements. For the strength calculation of the pressure retaining wall a reduced material value for the forgings has to taken into consideration. The material behaviour of Zircaloy 4 under irradiation up to a fluence of {approx}1{center_dot}10{sup 22} n/cm{sup 2} was investigated. The loss of ductility was determined. As an additional criteria the variation of the fracture toughness was studies. Fracture mechanic calculations of the material were carried out in the licensing procedure with the focus to fulfill the leak

  13. Effects of Size, Composition, and Evolutionary Pressure in Heterogeneous Cournot Oligopolies with Best Response Decisional Mechanisms

    Directory of Open Access Journals (Sweden)

    Fausto Cavalli

    2015-01-01

    Full Text Available We study heterogeneous Cournot oligopolies of variable sizes and compositions, in which the firms have different degrees of rationality, being either rational firms with perfect foresight or naive best response firms with static expectations. Each oligopoly can be described using its size and composition, that is, the fraction of firms that are rational. We take into account two frameworks, one in which the decisional rules are exogenously assigned and the other in which the firms may change their heuristics. We consider a switching mechanism based on a logit rule, where the switching propensity is regulated by a parameter which represents the evolutionary pressure. In the fixed fractions setting, we prove that, in general, the composition has a stabilizing effect, while increasing the oligopoly size leads to instability. However, we show that, for particular parameters settings, stability is not affected by the composition or the firms number. Similarly, in the evolutionary fractions setting, we analytically prove that when marginal costs are identical, increasing the evolutionary pressure has a destabilizing effect. Nevertheless, focusing on particular examples with different marginal costs we are able to show that evolutionary pressure may also have a stabilizing or a neutral role.

  14. Fracturing composition using the gas pressure generated by the thermit decomposition reaction

    Energy Technology Data Exchange (ETDEWEB)

    Okitsu, Toshihiro; Moriyama, Yoshihiro; Banno, Ryouichi

    1995-12-31

    The fracturing composition using the gas pressure generated by the thermit decomposition reaction gives the following performances: Heat of reaction--280 kcal/kg; Gas volume--330 l/kg; and Reaction rate--190 m/sec. With respect to many valuable data from the various fracturing experiments on sites, the results on breakage by the fracturing composition as compared with commercial explosives can be summarized as follows: (1) The specific charge of the fracturing composition is between two and four times that of a watergel explosive. (2) The ground vibration generated on breaking is between one-third and one-fourth that of the explosive. On the other hand, the sound level is between ten and twenty dB (A fast) lower than that of the explosive. (3) The fracturing composition can be applicable to any free faces breakage for the various brittle materials.

  15. The pressure-induced, lactose-dependent changes in the composition and size of casein micelles.

    Science.gov (United States)

    Wang, Pengjie; Jin, Shaoming; Guo, Huiyuan; Zhao, Liang; Ren, Fazheng

    2015-04-15

    The effects of lactose on the changes in the composition and size of casein micelles induced by high-pressure treatment and the related mechanism of action were investigated. Dispersions of ultracentrifuged casein micelle pellets with 0-10% (w/v) lactose were subjected to high pressure (400 MPa) at 20 °C for 40 min. The results indicated that the level of non-sedimentable caseins was positively related to the amount of lactose added prior to pressure treatment, and negatively correlated to the size. A mechanism for the pressure-induced, lactose-dependent changes in the casein micelles is proposed. Lactose inhibits the hydrophobic interactions between the micellar fragments during or after pressure release, through the hydrophilic layer formed by their hydrogen bonds around the micellar fragments. In addition, lactose does not favour the association between calcium and the casein aggregates after pressure release. Due to these two functions, lactose inhibited the formation of larger micelles after pressure treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. NASA Prototype All Composite Tank Cryogenic Pressure Tests to Failure with Structural Health Monitoring

    Science.gov (United States)

    Werlink, Rudolph J.; Pena, Francisco

    2015-01-01

    This Paper will describe the results of pressurization to failure of 100 gallon composite tanks using liquid nitrogen. Advanced methods of health monitoring will be compared as will the experimental data to a finite element model. The testing is wholly under NASA including unique PZT (Lead Zirconate Titanate) based active vibration technology. Other technologies include fiber optics strain based systems including NASA AFRC technology, Acoustic Emission, Acellent smart sensor, this work is expected to lead to a practical in-Sutu system for composite tanks.

  17. Shear bond strength of self-adhering flowable composite on dentin surface as a result of scrubbing pressure and duration

    OpenAIRE

    Ferry Jaya; Siti Triaminingsih; Andi Soufyan S; Yosi Kusuma Eriwati

    2012-01-01

    Background: Self-adhering flowable composite is a combination of composite resin and adhesive material. Its application needs scrubbing process on the dentin surface, but sometimes it is difficult to determine the pressure and duration of scrubbing. Purpose: This study was aimed to analyze the effect of scrubbing pressure and duration on shear bond strength of self-adhering flowable composite to dentin surface Methods: Fifty four mandibulary third molar were cut to get the dentin surface and ...

  18. Stress analysis of the reactor pressure vessel of the high performance light water reactors (HPLWR); Festigkeitsanalyse fuer den Reaktordruckbehaelter des High Performance Light Water Reactor (HPLWR)

    Energy Technology Data Exchange (ETDEWEB)

    Guelton, E.; Fischer, K.

    2006-12-15

    The High Performance Light Water Reactor (HPLWR) is one of the concepts of the Generation IV program. The main difference compared to current Light Water Reactors (LWR) results from the supercritical steam condition of the coolant. Due to the supercritical pressure of 25 MPa, water, used as moderator and coolant, flows as a single phase through the core. The temperatures at the outlet are above 500 C. These conditions have a major impact on the design of the Reactor Pressure Vessel (RPV). For the modelling a RPV concept is proposed, which resembles the design of current LWR and allows the use of approved materials on one side and also meets the additional demands on the other side. A first dimensioning of the RPV wall thicknesses and the geometrical proportions has been performed using the german KTA-guidelines. To verify these results, a stress analysis using the finite element method has been performed with the program ANSYS. The combined mechanical and thermal calculations provide the primary, secondary and peak stresses which are evaluated using the KTA-guidelines design loading (Level 0) and service loading level A for the different components. The results confirm the wall thicknesses estimated by Fischer et al. (2006), but there are peak stresses in the vicinity of the inlet and outlet flanges, which are very close to the allowed design limit. For larger diameters of the RPV those regions will become critical and the stresses might exceed the design limits. Design optimizations for those regions are proposed and evaluated. A readjusted geometry of the inlet flange reduces those stresses by 65%. (orig.)

  19. Contributions of Cu-rich clusters, dislocation loops and nanovoids to the irradiation-induced hardening of Cu-bearing low-Ni reactor pressure vessel steels

    Energy Technology Data Exchange (ETDEWEB)

    Bergner, F., E-mail: f.bergner@hzdr.de [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328 Dresden (Germany); Gillemot, F. [Centre for Energy Research of the Hungarian Academy of Sciences, 29-33 Konkoly-Thege street, 1121 Budapest XII (Hungary); Hernández-Mayoral, M.; Serrano, M. [Division of Materials, CIEMAT, Avenida Complutense 22, 28040 Madrid (Spain); Török, G. [Wigner Research Center for Physics of the Hungarian Academy of Sciences, 29-33 Konkoly-Thege street, 1121 Budapest XII (Hungary); Ulbricht, A.; Altstadt, E. [Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstr. 400, 01328 Dresden (Germany)

    2015-06-15

    Highlights: • TEM and SANS were applied to estimate mean size and number density of loops, nanovoids and Cu-rich clusters. • A three-feature dispersed-barrier hardening model was applied to estimate the yield stress increase. • The values and errors of the dimensionless obstacle strength were estimated in a consistent way. • Nanovoids are stronger obstacles for dislocation glide than dislocation loops, loops are stronger than Cu-rich clusters. • For reactor-relevant conditions, Cu-rich clusters contribute most to hardening due to their high number density. - Abstract: Dislocation loops, nanovoids and Cu-rich clusters (CRPs) are known to represent obstacles for dislocation glide in neutron-irradiated reactor pressure vessel (RPV) steels, but a consistent experimental determination of the respective obstacle strengths is still missing. A set of Cu-bearing low-Ni RPV steels and model alloys was characterized by means of SANS and TEM in order to specify mean size and number density of loops, nanovoids and CRPs. The obstacle strengths of these families were estimated by solving an over-determined set of linear equations. We have found that nanovoids are stronger than loops and loops are stronger than CRPs. Nevertheless, CRPs contribute most to irradiation hardening because of their high number density. Nanovoids were only observed for neutron fluences beyond typical end-of-life conditions of RPVs. The estimates of the obstacle strength are critically compared with reported literature data.

  20. High Fluency Low Flux Embrittlement Models of LWR Reactor Pressure Vessel Embrittlement and a Supporting Database from the UCSB ATR-2 Irradiation Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Odette, G. Robert [Univ. of California, Santa Barbara, CA (United States)

    2017-01-24

    Reactor pressure vessel embrittlement may limit the lifetime of light water reactors (LWR). Embrittlement is primarily caused by formation of nano-scale precipitates, which cause hardening and a subsequent increase in the ductile-to-brittle transition temperature of the steel. While the effect of Cu has historically been the largest research focus of RPV embrittlement, there is increasing evidence that Mn, Ni and Si are likely to have a large effect at higher fluence, where Mn-Ni-Si precipitates can form, even in the absence of Cu. Therefore, extending RPV lifetimes will require a thorough understanding of both precipitation and embrittlement at higher fluences than have ever been observed in a power reactor. To address this issue, test reactors that irradiate materials at higher neutron fluxes than power reactors are used. These experiments at high neutron flux can reach extended life neutron fluences in only months or several years. The drawback of these test irradiations is that they add additional complexity to interpreting the data, as the irradiation flux also plays a role into both precipitate formation and irradiation hardening and embrittlement. This report focuses on developing a database of both microstructure and mechanical property data to better understand the effect of flux. In addition, a previously developed model that enables the comparison of data taken over a range of neutron flux is discussed.

  1. The changes of the structural, magnetic, and mechanical properties in a reactor pressure vessel steel neutron-irradiated at 70 .deg. C

    CERN Document Server

    Park, D G; Jang, K S; Jung, M M; Kim, G M

    1999-01-01

    The irradiation embrittlement of reactor-pressure-vessel steel has been one of the main safety concerns in nuclear power plants. In the present study, an SA508-3 RPV steel was irradiated by neutrons with various fluences up to 10 sup 1 sup 8 n/cm sup 2 (E>=1MeV) at a temperature of approximately 70 .deg. C. The irradiation responses of the structural, the magnetic, and the mechanical properties of the steel were investigated by means of X-ray diffraction, Moessbauer spectroscopy, magnetic Barkhausen noise, and micro-Vickers hardness measurements. The transitions of all of these parameters occurred above a neutron does of 10 sup 1 sup 6 n/cm sup 2. The results of the X-ray and the Moessbauer experiments revealed that neutron irradiation led to the possibility of partial amorphization in the investigated RPV steel. The changes of the physical and the mechanical properties were discussed in terms of irradiation-induced cascade damage of crystalline materials.

  2. Evaluation of Thermodynamic Stable Phase and Microstructure of SA508 Gr.4N Model Alloys for Reactor Pressure Vessel Steel with Variation of Alloying Elements

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Mim Chul; Lee, B. S

    2009-12-15

    In order to increase the strength and the fracture toughness of RPV(reactor pressure vessel) steels, an effective way is the change of material specification from Mn-Mo-Ni low alloy steel(SA508 Gr.3) into Ni-Mo-Cr low alloy steel(SA508 Gr.4N). In this study, we evaluate the effects of alloying elements on microstructural characteristics in Ni-Mo-Cr low alloy steel. The changes in stable phase of SA508 Gr.4N low alloy steel with alloying elements were evaluated using a thermodynamic calculation by ThermoCalc software, and then compared with its microstructural observation results. From the calculation of Ni-Mo-Cr low alloy steels, ferrite formation temperature were decreased with increasing Ni and Mn contents due to austenite stabilization effect. Consequently, in the microscopic observation, the microstructure became finer with increasing Ni and Mn contents. However, they does not affects the carbide phase such as M{sub 23}C{sub 6} and M{sub 7}C{sub 3}. When the content of Cr is decreased, carbide phases became unstable and carbide coarsening is observed. With increase of Mo content, M{sub 2}C phase become stable instead of M{sub 7}C{sub 3} and it also observed in the TEM.

  3. Mechanical properties of a modified 2 1/4 Cr-1 Mo steel for pressure vessel applications. [V-Ti-B-modified

    Energy Technology Data Exchange (ETDEWEB)

    Klueh, R.L.; Swindeman, R.W.

    1983-12-01

    Tensile and creep properties were determined on a V-Ti-B-modified 2 1/4 Cr-1 Mo steel considered to be a candidate alloy for pressure vessel aplications for coal liquefaction. The modified 2 1/4 Cr-1 Mo steel had about 0.2% V added for improved elevated-temperature strength and 0.02% Ti for grain refinement. Boron was added to improve the hardenability, thus allowing thicker sections to be quenched and normalized to completely bainitic microstructures. Lower carbon and silicon concentrations were used (approx. 0.1% C and 0.02% Si) than in standard 2 1/4 Cr-1 Mo steel. The mechanical properties determined on the modified steel after a heat treatment typical for SA-387, grade 22, class 2, indicated high toughness and excellent elecated-temperature tensile and creep strength. The modified steel had substantially better stress-rupture properties than did a standard 2 1/4 Cr-1 Mo steel (both with bainitic microstructures) with equivalent tensile properties - especially at the lowest stresses and highest temperatures. The modified steel had toughness properties superior to those of the standard 2 1/4 Cr-1 Mo steel. Comparative transmission electron microscopy studies of the standard and modified 2 1/4 Cr-1 Mo steels indicated that the differences involve the carbide precipitates and the dislocation substructures present in the steels.

  4. Influence of Modelling Options in RELAP5/SCDAPSIM and MAAP4 Computer Codes on Core Melt Progression and Reactor Pressure Vessel Integrity

    Directory of Open Access Journals (Sweden)

    Siniša Šadek

    2010-01-01

    Full Text Available RELAP5/SCDAPSIM and MAAP4 are two widely used severe accident computer codes for the integral analysis of the core and the reactor pressure vessel behaviour following the core degradation. The objective of the paper is the comparison of code results obtained by application of different modelling options and the evaluation of influence of thermal hydraulic behaviour of the plant on core damage progression. The analysed transient was postulated station blackout in NPP Krško with a leakage from reactor coolant pump seals. Two groups of calculations were performed where each group had a different break area and, thus, a different leakage rate. Analyses have shown that MAAP4 results were more sensitive to varying thermal hydraulic conditions in the primary system. User-defined parameters had to be carefully selected when the MAAP4 model was developed, in contrast to the RELAP5/SCDAPSIM model where those parameters did not have any significant impact on final results.

  5. Design and fabrication report on instrumented capsule (99M-01K.02H) for korean reactor pressure vessel material made by HANJUNG (Co)

    Energy Technology Data Exchange (ETDEWEB)

    Choo, K. N.; Kang, Y. H.; Kim, B. G.; Cho, M. S.; Son, J. M.; Kim, D. S.; Oh, J. M.; Park, S. J.; Shin, Y. T

    2000-09-01

    The instrumented capsules (99M-01K{center_dot}02H) was designed and fabricated. The purpose of the capsules were to evaluate the nuclear irradiation performance of the Korean nuclear reactor pressure vessel material, SA508 class 3 steel, fabricated by HANJUNG Co for Yonggwang Units 4,5 and Ulchin Unit 4. There are 5 stages having specimens and independent electric heaters in the capsule mainbody. 12 K-type thermocouples and 5 sets of Ni-Ti-Fe and sapphire neutron Fluence Monitors were also inserted in the apsule. Various types of specimens, such as round compact tension, Charpy insert, pre-cracked v-notch (PCVN), tensile, small punch (SP), magnetic Barkhausen effect (MBE), and transmission electron micrograph (TEM) specimens, were inserted in the capsule. The capsule was fabricated at DAEWOO Precision Co. according to KAERI detailed design specifications. This report describes the details of the design, fabrication and inspection of the 99M-01K and 99M-02H capsule. The capsules were irradiated in the IR2 test hole of HANARO at 290{+-}10 deg C up to the fast neutron fluence (E>1.0 MeV) of 3.0x10{sup 19} (n/cm{sup 2})

  6. A novel high-pressure vessel for simultaneous observations of seismic velocity and in situ CO2 distribution in a porous rock using a medical X-ray CT scanner

    Science.gov (United States)

    Jiang, Lanlan; Nishizawa, Osamu; Zhang, Yi; Park, Hyuck; Xue, Ziqiu

    2016-12-01

    Understanding the relationship between seismic wave velocity or attenuation and CO2 saturation is essential for CO2 storage in deep saline formations. In the present study, we describe a novel upright high-pressure vessel that is designed to keep a rock sample under reservoir conditions and simultaneously image the entire sample using a medical X-ray CT scanner. The pressure vessel is composed of low X-ray absorption materials: a carbon-fibre-enhanced polyetheretherketone (PEEK) cylinder and PEEK vessel closures supported by carbon-fibre-reinforced plastic (CFRP) joists. The temperature was controlled by a carbon-coated film heater and an aramid fibre thermal insulator. The assembled sample cell allows us to obtain high-resolution images of rock samples during CO2 drainage and brine imbibition under reservoir conditions. The rock sample was oriented vertical to the rotation axis of the CT scanner, and seismic wave paths were aligned parallel to the rotation axis to avoid shadows from the acoustic transducers. The reconstructed CO2 distribution images allow us to calculate the CO2 saturation in the first Fresnel zone along the ray path between transducers. A robust relationship between the seismic wave velocity or attenuation and the CO2 saturation in porous rock was obtained from experiments using this pressure vessel.

  7. Quantitative analysis of mutation and selection pressures on base composition skews in bacterial chromosomes

    Directory of Open Access Journals (Sweden)

    Chen Carton W

    2007-08-01

    Full Text Available Abstract Background Most bacterial chromosomes exhibit asymmetry of base composition with respect to leading vs. lagging strands (GC and AT skews. These skews reflect mainly those in protein coding sequences, which are driven by asymmetric mutation pressures during replication and transcription (notably asymmetric cytosine deamination plus subsequent selection for preferred structures, signals, amino acid or codons. The transcription-associated effects but not the replication-associated effects contribute to the overall skews through the uneven distribution of the coding sequences on the leading and lagging strands. Results Analysis of 185 representative bacterial chromosomes showed diverse and characteristic patterns of skews among different clades. The base composition skews in the coding sequences were used to derive quantitatively the effect of replication-driven mutation plus subsequent selection ('replication-associated pressure', RAP, and the effect of transcription-driven mutation plus subsequent selection at translation level ('transcription-associate pressure', TAP. While different clades exhibit distinct patterns of RAP and TAP, RAP is absent or nearly absent in some bacteria, but TAP is present in all. The selection pressure at the translation level is evident in all bacteria based on the analysis of the skews at the three codon positions. Contribution of asymmetric cytosine deamination was found to be weak to TAP in most phyla, and strong to RAP in all the Proteobacteria but weak in most of the Firmicutes. This possibly reflects the differences in their chromosomal replication machineries. A strong negative correlation between TAP and G+C content and between TAP and chromosomal size were also revealed. Conclusion The study reveals the diverse mutation and selection forces associated with replication and transcription in various groups of bacteria that shape the distinct patterns of base composition skews in the chromosomes during

  8. Effects of Fuel Composition and Pressure on Auto ignition Delay of Biomass Syngas

    Energy Technology Data Exchange (ETDEWEB)

    Shim, Tae Young; Kang, Ki Joong; Choi, Gyung Min; Kim, Duck Jool [Pusan National Univ., Busan (Korea, Republic of); Lu, Xingcai [Shanghai Jiao Tong Univ., Shanghai (China)

    2015-12-15

    The autoignition characteristics of biosyngas were investigated both numerically and experimentally. The effects of the temperature, gas composition, and pressure on the autoignition characteristics were evaluated. A shock tube was employed to measure the ignition delay times of the biosyngas. The numerical study on the ignition delay time was performed using the CHEMKIN-PRO software to validate the experimental results and predict the chemical species in the combustion process. The results revealed that the ignition delay time increased with an increase in the hydrogen fraction in the mixture. Under most temperature conditions, the ignition delay time decreased with a pressure increase. However, the ignition delay time increased with an increase in pressure under relatively low temperature conditions.

  9. Analysis and Testing of a Metallic Repair Applicable to Pressurized Composite Aircraft Structure

    Science.gov (United States)

    Przekop, Adam; Jegley, Dawn C.; Rouse, Marshall; Lovejoy, Andrew E.

    2014-01-01

    Development of repair technology is vital to the long-term application of new structural concepts on aircraft structure. The design, analysis, and testing of a repair concept applicable to a stiffened composite panel based on the Pultruded Rod Stitched Efficient Unitized Structure was recently completed. The damage scenario considered was a mid-bay to mid-bay saw-cut with a severed stiffener, flange, and skin. A bolted metallic repair was selected so that it could be easily applied in the operational environment. The present work describes results obtained from tension and pressure panel tests conducted to validate both the repair concept and finite element analysis techniques used in the design effort. Simulation and experimental strain and displacement results show good correlation, indicating that the finite element modeling techniques applied in the effort are an appropriate compromise between required fidelity and computational effort. Static tests under tension and pressure loadings proved that the proposed repair concept is capable of sustaining load levels that are higher than those resulting from the current working stress allowables. Furthermore, the pressure repair panel was subjected to 55,000 pressure load cycles to verify that the design can withstand a life cycle representative for a transport category aircraft. These findings enable upward revision of the stress allowables that had been kept at an overly-conservative level due to concerns associated with repairability of the panels. This conclusion enables more weight efficient structural designs utilizing the composite concept under investigation.

  10. In Arabidopsis thaliana codon volatility scores reflect GC3 composition rather than selective pressure

    Directory of Open Access Journals (Sweden)

    O'Connell Mary J

    2012-07-01

    Full Text Available Abstract Background Synonymous codon usage bias has typically been correlated with, and attributed to translational efficiency. However, there are other pressures on genomic sequence composition that can affect codon usage patterns such as mutational biases. This study provides an analysis of the codon usage patterns in Arabidopsis thaliana in relation to gene expression levels, codon volatility, mutational biases and selective pressures. Results We have performed synonymous codon usage and codon volatility analyses for all genes in the A. thaliana genome. In contrast to reports for species from other kingdoms, we find that neither codon usage nor volatility are correlated with selection pressure (as measured by dN/dS, nor with gene expression levels on a genome wide level. Our results show that codon volatility and usage are not synonymous, rather that they are correlated with the abundance of G and C at the third codon position (GC3. Conclusions Our results indicate that while the A. thaliana genome shows evidence for synonymous codon usage bias, this is not related to the expression levels of its constituent genes. Neither codon volatility nor codon usage are correlated with expression levels or selective pressures but, because they are directly related to the composition of G and C at the third codon position, they are the result of mutational bias. Therefore, in A. thaliana codon volatility and usage do not result from selection for translation efficiency or protein functional shift as measured by positive selection.

  11. Fluid flow separation in a reactor pressure vessel during an ECC injection. Single phase flow and two phase flow (air-water) experimental results

    Energy Technology Data Exchange (ETDEWEB)

    Thierry Bichet; Alain Martin [EDF - Research and Development Division - Fluid Mechanics and Heat Transfert 6, quai Watier - B.P. 49 - 78401 Chatou CEDEX 01 (France); Frederic Beaud [EDF/ Industry - Basic Design Department., 12-14, Avenue Dutrievoz 69628 Villeurbanne CEDEX (France)

    2005-07-01

    Full text of publication follows: Within the framework of the nuclear power plant lifetime issue, the assessment of the French 900 MWe (3-loops) series reactor pressure vessel (RPV) integrity has been performed. A simplified analysis has shown that the most severe loading conditions are given by the small break loss of coolant accidents due to the pressurized injection of cold water (9 deg. C) into the cold leg and down comer of the RPV. During these transient scenarios, single or two-phase (uncovered cold leg) flows have been shown in the cold leg, depending on the crack size and RPV model (900 MWe or 1300 MWe). An experimental study has been carried out, on the one hand, to consolidate the numerical results obtained with CFD home code (Code-Saturne) which mainly showed the stratified flow in the cold leg and the fluid flow separation and its oscillations in the down comer during a single phase scenario. These physical phenomena are important for the thermal RPV loading assessment. On the other hand, the absence of experimental two-phase data necessitated to carry out an experimental study around the mixing area behavior (free surface, stratified flow) during an ECC injection with an uncovered cold leg. The new EDF R and D mock up, called HYBISCUS, is a facility which is made out of Plexiglas (atmosphere pressure) and represents a half scale CP0 geometry with one cold leg and part of the down comer. The mock up modularity allows us to insert representative ECC nozzles and a thermal shield. In reference to the reactor scenarios, the experimental operating conditions are derived from the conservation of the density effects (Froude number). For that, a heated salted water flow is used to represent the ECC injection whereas water represents the cold leg fluid. This mock up has been defined in order to represent single phase flow (cold leg and down comer full of water) or two-phase flow (uncovered cold leg) ECC scenarios. This paper reports experimental results

  12. Matrix free fiber reinforced polymeric composites via high-temperature high-pressure sintering

    Science.gov (United States)

    Xu, Tao

    2004-11-01

    A novel manufacturing process called high-temperature high-pressure sintering was studied and explored. Solid fiber reinforced composites are produced by consolidating and compacting layers of polymeric fabrics near their melting temperature under high pressure. There is no need to use an additional matrix as a bonding material. Partial melting and recrystallization of the fibers effectively fuse the material together. The product is called a "matrix free" fiber reinforced composite and essentially a one-polymer composite in which the fiber and the matrix have the same chemical composition. Since the matrix is eliminated in the process, it is possible to achieve a high fiber volume fraction and light weight composite. Interfacial adhesion between fibers and matrix is very good due to the molecular continuity throughout the system and the material is thermally shapeable. Plain woven Spectra RTM cloth made of SpectraRTM fiber was used to comprehensively study the process. The intrinsic properties of the material demonstrate that matrix free SpectraRTM fiber reinforced composites have the potential to make ballistic shields such as body armor and helmets. The properties and structure of the original fiber and the cloth were carefully examined. Optimization of the processing conditions started with the probing of sintering temperatures by Differential Scanning Calorimetry. Coupled with the information from structural, morphological and mechanical investigations on the samples sintered at different processing conditions, the optimal processing windows were determined to ensure that the outstanding original properties of the fibers translate into high ballistic performance of the composites. Matrix free SpectraRTM composites exhibit excellent ballistic resistance in the V50 tests conducted by the US Army. In the research, process-structure-property relationship is established and correlations between various properties and structures are understood. Thorough knowledge is

  13. A pressure-sensitive carbon black cement composite for traffic monitoring

    KAUST Repository

    Monteiro, A.O.

    2017-08-17

    Recent advances in nanotechnology have guided the development of a new generation of multifunctional construction materials. An example of this are cement-based composites, some of which can be used not just to pave roads but also to monitor them. A cement composite, integrating a carbon black (CB) filler, was used as a piezoresistive sensor to identify different cyclic compressive loadings, at temperatures ranging from 15°C to 45°C. The mechanical essays were performed under realistic conditions using 600cm3 specimens and uniaxial loads typical of automobile traffic. A linear and reversible pressure-sensing performance was found with gauge factors ranging from 40 to 60. Overall, these results show that CB/cement composites can act as stress-sensitive materials for traffic monitoring.

  14. Research vessels

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, P.S.

    by the research vessels RV Gaveshani and ORV Sagar Kanya are reported. The work carried out by the three charted ships is also recorded. A short note on cruise plans for the study of ferromanganese nodules is added...

  15. Development of Critical Profilometers to Meet Current and Future NASA Composite Overwrapped Pressure Vessel (COPV) Inspection Needs

    Science.gov (United States)

    Saulsberry, Regor; Nichols, Charles

    2012-01-01

    This project is part of a multi-center effort to develop and validate critical NDE techniques which can be implemented into current and future NASA spacecraft COPV manufacturing processes. After decades of COPV development, manufacturing variance is still high and has necessitated higher safety factors and additional mass to be flown on spacecraft (reducing overall performance). Additionally, the NASA Engineering and Safety Center (NESC) indicated that nondestructive evaluation (NDE) was not adequately implemented during Shuttle and International Space Station (ISS) COPV manufacturing and provisions were not made for on-going structural integrity and health checks during the various spacecraft programs. This project helps to provide additional data needed to help address these issues. This project seeks to develop and install internal and external laser profilometers at COPV manufacturing facilities to provide data needed to improve COPV quality and consistency. This project also investigates other scanning techniques that will enhance the system to more completely meet manufacturing needs, thus transforming the profilometer into what has been termed the "Universal Manufacturing COPV Scanner".

  16. Effect of high-temperature water and hydrogen on the fracture behavior of a low-alloy reactor pressure vessel steel

    Energy Technology Data Exchange (ETDEWEB)

    Roychowdhury, S., E-mail: sroy27@gmail.com [Paul Scherrer Institut, Nuclear Energy and Safety Research Department, Laboratory for Nuclear Materials, 5232 Villigen, PSI (Switzerland); Materials Processing & Corrosion Engineering Division, Mod-Lab, D-Block, Bhabha Atomic Research Centre, Mumbai 400085 (India); Seifert, H.-P.; Spätig, P.; Que, Z. [Paul Scherrer Institut, Nuclear Energy and Safety Research Department, Laboratory for Nuclear Materials, 5232 Villigen, PSI (Switzerland)

    2016-09-15

    Structural integrity of reactor pressure vessels (RPV) is critical for safety and lifetime. Possible degradation of fracture resistance of RPV steel due to exposure to coolant and hydrogen is a concern. In this study tensile and elastic-plastic fracture mechanics (EPFM) tests in air (hydrogen pre-charged) and EFPM tests in hydrogenated/oxygenated high-temperature water (HTW) was done, using a low-alloy RPV steel. 2–5 wppm hydrogen caused embrittlement in air tensile tests at room temperature (25 °C) and at 288 °C, effects being more significant at 25 °C and in simulated weld coarse grain heat affected zone material. Embrittlement at 288 °C is strain rate dependent and is due to localized plastic deformation. Hydrogen pre-charging/HTW exposure did not deteriorate the fracture resistance at 288 °C in base metal, for investigated loading rate range. Clear change in fracture morphology and deformation structures was observed, similar to that after air tests with hydrogen. - Highlights: • Hydrogen content, microstructure of LAS, and strain rate affects tensile properties at 288 °C. • Strength affects hydrogen embrittlement susceptibility to a greater extent than grain size. • Hydrogen in LAS leads to strain localization and restricts cross-slip at 288 °C. • Possible hydrogen pickup due to exposure to 288 °C water alters fracture surface appearance without affecting fracture toughness in bainitic base material. • Simulated weld heat affected zone microstructure shows unstable crack propagation in 288 °C water.

  17. Master curve analysis of the SA508 Gr. 4N Ni-Mo-Cr low alloy steels for reactor pressure vessels

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ki Hyoung; Wee, Dang Moon [KAIST, Daejeon (Korea, Republic of); Kim, Min Chul; Lee, Bong Sang [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2009-10-15

    Low alloy steels used as Reactor Pressure Vessels (RPVs) materials directly relate to the safety margin and the life span of reactors. Currently, SA508 Gr.3 low alloy steel is generally used for RPV material. But, for larger capacity and long-term durability of RPV, materials that have better properties including strength and toughness are needed. Therefore, tempered martensitic SA508 Gr.4N low alloy steel is considered as a candidate material due to excellent mechanical properties. The fracture toughness loss caused by irradiation embrittlement during reactor operation is one of the important issues for ferritic RPV steels, because the decrease of fracture toughness is directly related to the integrity of RPVs. One reliable and efficient concept to evaluate the fracture toughness of ferritic steels is master curve method. In ASTM E1921, it is clearly mentioned the universal shape of the median toughness-temperature curve for ferritic steels including tempered martensitic steels. However, currently, concerns have arisen regarding the appropriateness of the universal shape in ASTM for the tempered martensitic steels such as Eurofer97. Therefore, it may be necessary to assess the master curve applicability for the tempered martensitic SA508 Gr.4N low alloy steel. In this study, the fracture toughness behavior with temperature of the tempered martensitic SA508 Gr.4N low alloy steels was evaluated using the ASTM E1921 master curve method. And the results were compared with those of the bainitic SA508 Gr.3 low alloy steel. Furthermore, the way to define the fracture toughness behavior of Gr.4N steels well is discussed.

  18. Progressive Fracture of Fiber Composite Thin Shell Structures Under Internal Pressure and Axial Loads

    Science.gov (United States)

    Gotsis, Pascal K.; Chamis, Christos C.; Minnetyan, Levon

    1996-01-01

    Graphite/epoxy composite thin shell structures were simulated to investigate damage and fracture progression due to internal pressure and axial loading. Defective and defect-free structures (thin cylinders) were examined. The three different laminates examined had fiber orientations of (90/0/+/-0)(sub s), where 0 is 45, 60, and 75 deg. CODSTRAN, an integrated computer code that scales up constituent level properties to the structural level and accounts for all possible failure modes, was used to simulate composite degradation under loading. Damage initiation, growth, accumulation, and propagation to fracture were included in the simulation. Burst pressures for defective and defect-free shells were compared to evaluate damage tolerance. The results showed that damage initiation began with matrix failure whereas damage and/or fracture progression occurred as a result of additional matrix failure and fiber fracture. In both thin cylinder cases examined (defective and defect-free), the optimum layup configuration was (90/0/+/-60)(sub s) because it had the best damage tolerance with respect to the burst pressure.

  19. Amine Enrichment of Thin-Film Composite Membranes via Low Pressure Plasma Polymerization for Antimicrobial Adhesion.

    Science.gov (United States)

    Reis, Rackel; Dumée, Ludovic F; He, Li; She, Fenghua; Orbell, John D; Winther-Jensen, Bjorn; Duke, Mikel C

    2015-07-15

    Thin-film composite membranes, primarily based on poly(amide) (PA) semipermeable materials, are nowadays the dominant technology used in pressure driven water desalination systems. Despite offering superior water permeation and salt selectivity, their surface properties, such as their charge and roughness, cannot be extensively tuned due to the intrinsic fabrication process of the membranes by interfacial polymerization. The alteration of these properties would lead to a better control of the materials surface zeta potential, which is critical to finely tune selectivity and enhance the membrane materials stability when exposed to complex industrial waste streams. Low pressure plasma was employed to introduce amine functionalities onto the PA surface of commercially available thin-film composite (TFC) membranes. Morphological changes after plasma polymerization were analyzed by SEM and AFM, and average surface roughness decreased by 29%. Amine enrichment provided isoelectric point changes from pH 3.7 to 5.2 for 5 to 15 min of plasma polymerization time. Synchrotron FTIR mappings of the amine-modified surface indicated the addition of a discrete 60 nm film to the PA layer. Furthermore, metal affinity was confirmed by the enhanced binding of silver to the modified surface, supported by an increased antimicrobial functionality with demonstrable elimination of E. coli growth. Essential salt rejection was shown minimally compromised for faster polymerization processes. Plasma polymerization is therefore a viable route to producing functional amine enriched thin-film composite PA membrane surfaces.

  20. Structure, Mobility, and Composition of Transition Metal Catalyst Surfaces. High-Pressure Scanning Tunneling Microscopy and Ambient-Pressure X-ray Photoelectron Spectroscopy Studies

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Zhongwei [Univ. of California, Berkeley, CA (United States)

    2013-12-06

    Surface structure, mobility, and composition of transition metal catalysts were studied by high-pressure scanning tunneling microscopy (HP-STM) and ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) at high gas pressures. HP-STM makes it possible to determine the atomic or molecular rearrangement at catalyst surfaces, particularly at the low-coordinated active surface sites. AP-XPS monitors changes in elemental composition and chemical states of catalysts in response to variations in gas environments. Stepped Pt and Cu single crystals, the hexagonally reconstructed Pt(100) single crystal, and Pt-based bimetallic nanoparticles with controlled size, shape and composition, were employed as the model catalysts for experiments in this thesis.

  1. Computational evaluation of the constraint loss on the fracture toughness of reactor pressure vessel steels; Evaluacion computacional del efecto de la perdida de constriccion en la tenacidad de fractura de la vasija de reactores nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Serrano Garcia, M.

    2007-07-01

    The Master Curve approach is included on the ASME Code through some Code Cases to assess the reactor pressure vessel integrity. However, the margin definition to be added is not defined as is the margin to be added when the Master Curve reference temperature T{sub 0} is obtained by testing pre-cracked Charpy specimens. The reason is that the T{sub 0} value obtained with this specimen geometry is less conservative than the value obtained by testing compact tension specimens possible due to a loss of constraint. The two parameter fracture mechanics, considered as an extension of the classical fracture mechanics, coupled to a micromechanical fracture models is a valuable tool to assess the effect of constraint loss on fracture toughness. The definition of a parameter able to connect the fracture toughens value to the constraint level on the crack tip will allow to quantify margin to be added to the T{sub 0} value when this value is obtained testing the pre-cracked Charpy specimens included in the surveillance capsule of the reactor pressure vessel. The Nuclear Regulatory Commission (NRC) define on the To value obtained by testing compact tension specimens and ben specimens (as pre-cracked Charpy are) bias. the NRC do not approved any of the direct applications of the Master Curve the reactor pressure vessel integrity assessment until this bias will be quantified in a reliable way. the inclusion of the bias on the integrity assessment is done through a margin to be added. In this thesis the bias is demonstrated an quantified empirical and numerically and a generic value is suggested for reactor pressure vessel materials, so that it can be used as a margin to be added to the T{sub 0} value obtained by testing the Charpy specimens included in the surveillance capsules. (Author) 111 ref.

  2. Metal Matrix Composite LOX Turbopump Housing via Novel Tool-less Net-Shape Pressure Infiltration Casting Technology

    Science.gov (United States)

    Shah, Sandeep; Lee, Jonathan; Bhat, Biliyar; Wells, Doug; Gregg, Wayne; Marsh, Matthew; Genge, Gary; Forbes, John; Salvi, Alex; Cornie, James A.

    2003-01-01

    Metal matrix composites for propulsion components offer high performance and affordability, resulting in low weight and cost. The following sections in this viewgraph presentation describe the pressure infiltration casting of a metal matrix composite LOX turbopump housing: 1) Baseline Pump Design and Stress Analysis; 2) Tool-less Advanced Pressure Infiltration Casting Process; 3) Preform Splicing and Joining for Large Components such as Pump Housing; 4) Fullscale Pump Housing Redesign.

  3. Coefficient of Friction Measurements for Thermoplastics and Fiber Composites under Low Sliding Velocity and High Pressure

    DEFF Research Database (Denmark)

    Poulios, Konstantinos; Svendsen, G.; Hiller, Jochen

    2012-01-01

    Friction materials for typical brake applications are normally designed considering thermal stability as the major performance criterion. There are however brake applications with very limited sliding velocities, where the generated heat is insignificant. In such cases it is possible that friction...... materials which are untypical for brake applications, like thermoplastics and fiber composites, can offer superior performance in terms of braking torque, wear resistance and cost than typical brake linings. In this paper coefficient of friction measurements for various thermoplastic and fiber composite...... materials running against a steel surface are presented. All tests were carried out on a pin-on-disc test-rig at a fixed sliding speed and various pressure levels for both dry and grease lubricated conditions....

  4. Atmospheric pressure plasma treatment of glass fibre composite for adhesion improvement

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Mortensen, H.; Stenum, Bjarne

    2007-01-01

    treated for more than 30 s. X-Ray photoelectron spectroscopic analysis showed that the contents of aluminium and oxygen on the surface increased with the plasma treatment. The adhesion strength of the 2-s treated surface was comparable to or higher than that achieved by conventional mechanical surface......Glass-fibre-reinforced polyester composite plates were treated with an atmospheric pressure dielectric barrier discharge. Synthetic air was used as the treatment gas. The water contact angle dropped markedly from 84 to 22° after a 2-s treatment, and decreased to 0° when the composite plates were...... roughening. It decreased when the surfaces were treated for 5 and 15 s, but recovered for 30-s treatment....

  5. Structure integrity assessment of pressurizer

    Energy Technology Data Exchange (ETDEWEB)

    Gubeljak, N.; Predan, J. (University of Maribor, Faculty of Mech. Eng., Maribor (Slovenia)); Vojvodie-Tuma, J. (Inst. for Metals and Technology, Ljubljana (Slovenia)); Kljajin, M. (University of Osijek, Faculty of Mech. Engineering , Brod (Croatia))

    2009-07-01

    Mechanical properties and fracture toughness testing of substrate pressurizer material is performed on simulated cast with same chemical composition and same production treatment as original material in Nuclear Power Plant. Tests were performed on artificially 2 years aged specimens at service temperature 300 deg C. The fracture toughness values in term of J-integral=81 N/mm was determined according to ASTM test procedure. Mechanical properties of clad and weld metal are taken from ASME Boiler and Pressure Vessel Code. Considering the material and physical properties of pressurizer bottom and internal pressure, the numerical analysis of displacement and stress distribution through the thickness was performed

  6. Adsorption of Molecular Gases on Silver/Carbon Nanotube Composites at Low Temperatures and Low Pressures

    Directory of Open Access Journals (Sweden)

    M. Barberio

    2014-01-01

    Full Text Available We present an experimental study adsorption of molecular gases (N2, H2, O2, CH4, C2H4, and C2H6 on multiwalled carbon nanotubes (MWCNTs and MWCNT doped with Ag at low temperatures (35 K and pressures (10−6 Torr using the temperature programmed desorption technique. Our results show that the desorption kinetics is of the first order; furthermore comparative measurements indicate that Ag/MWCNTs have an adsorption capacity higher than that of a pure sample suggesting that these composites are good candidates as gas cryosorbers for applications in cryopumps or sensor of latest generation.

  7. Compositional Differences of Ojeok-san (Wuji-san Decoctions Using Pressurized or Non-pressurized Methods for Variable Extraction Times

    Directory of Open Access Journals (Sweden)

    Kim Jung-Hoon

    2012-06-01

    Full Text Available This study compared Ojeok-san (Wuji-san in Chinese decoctions produced using different extraction methods for variable times. Decoctions were extracted in pressurized or non-pressurized conditions for 60, 120, and 180 mins. We investigated the Ojeok-san extract yield, the total soluble solid content, the hydrogen ion concentration (pH, and the reference compound content. The extract yield and the total soluble solid content were higher in decoctions produced by non-pressurized extraction; both were proportional to the extraction time. The pH tended to decrease as the extraction time was increased in decoctions produced using both methods. After 60 and 180 mins, the levels of albiflorin, paeoniflorin, nodakenin, naringin, and neohesperidin were significantly higher in decoctions extracted using the non-pressurized method compared with those extracted using the pressurized method. After 120 mins, only cinnamaldehyde was extracted in a greater amount in pressurized decoctions compared with non-pressurized decoctions. The levels of paeoniflorin, ferulic acid, nodakenin, naringin, hesperidin, neohesperidin, and glycyrrhizin increased with time in non-pressurized decoctions. This study showed that the use of pressurized and non-pressurized extraction methods for different times affected the composition of Ojeoksan (Wuji-san decoctions.

  8. Compositional Differences of Ojeok-san (Wuji-san) Decoctions Using Pressurized or Non-pressurized Methods for Variable Extraction Times.

    Science.gov (United States)

    Kim, Jung-Hoon; Seo, Chang-Seob; Kim, Seong-Sil; Shin, Hyeun-Kyoo

    2012-06-01

    This study compared Ojeok-san (Wuji-san in Chinese) decoctions produced using different extraction methods for variable times. Decoctions were extracted in pressurized or non-pressurized conditions for 60, 120, and 180 mins. We investigated the Ojeok-san extract yield, the total soluble solid content, the hydrogen ion concentration (pH), and the reference compound content. The extract yield and the total soluble solid content were higher in decoctions produced by non-pressurized extraction; both were proportional to the extraction time. The pH tended to decrease as the extraction time was increased in decoctions produced using both methods. After 60 and 180 mins, the levels of albiflorin, paeoniflorin, nodakenin, naringin, and neohesperidin were significantly higher in decoctions extracted using the non-pressurized method compared with those extracted using the pressurized method. After 120 mins, only cinnamaldehyde was extracted in a greater amount in pressurized decoctions compared with non-pressurized decoctions. The levels of paeoniflorin, ferulic acid, nodakenin, naringin, hesperidin, neohesperidin, and glycyrrhizin increased with time in non-pressurized decoctions. This study showed that the use of pressurized and non-pressurized extraction methods for different times affected the composition of Ojeoksan (Wuji-san) decoctions.

  9. Hazard of underclad cracks and aging in pressurized water reactor vessels; Nocivite des defauts sous revetement et vieillissement dans les cuves de reacteur a eau sous pression

    Energy Technology Data Exchange (ETDEWEB)

    Piques, R.; Saintier, N. [Ecole Nationale Superieure des Mines, 75 - Paris (France). Centre des Materiaux

    2001-04-01

    The following topics are dealt with: hazards due to underclad cracks, carbon rich impurity segregation and embrittlement, corrosion protection by austenitic vessel cladding, aging influence, quenching and thermal treatments, Beremin-type statistical model of ruptures, rupture probability.

  10. Composite Behavior of Insulated Concrete Sandwich Wall Panels Subjected to Wind Pressure and Suction

    Directory of Open Access Journals (Sweden)

    Insub Choi

    2015-03-01

    Full Text Available A full-scale experimental test was conducted to analyze the composite behavior of insulated concrete sandwich wall panels (ICSWPs subjected to wind pressure and suction. The experimental program was composed of three groups of ICSWP specimens, each with a different type of insulation and number of glass-fiber-reinforced polymer (GFRP shear grids. The degree of composite action of each specimen was analyzed according to the load direction, type of the insulation, and number of GFRP shear grids by comparing the theoretical and experimental values. The failure modes of the ICSWPs were compared to investigate the effect of bonds according to the load direction and type of insulation. Bonds based on insulation absorptiveness were effective to result in the composite behavior of ICSWP under positive loading tests only, while bonds based on insulation surface roughness were effective under both positive and negative loading tests. Therefore, the composite behavior based on surface roughness can be applied to the calculation of the design strength of ICSWPs with continuous GFRP shear connectors.

  11. Composite Behavior of Insulated Concrete Sandwich Wall Panels Subjected to Wind Pressure and Suction.

    Science.gov (United States)

    Choi, Insub; Kim, JunHee; Kim, Ho-Ryong

    2015-03-19

    A full-scale experimental test was conducted to analyze the composite behavior of insulated concrete sandwich wall panels (ICSWPs) subjected to wind pressure and suction. The experimental program was composed of three groups of ICSWP specimens, each with a different type of insulation and number of glass-fiber-reinforced polymer (GFRP) shear grids. The degree of composite action of each specimen was analyzed according to the load direction, type of the insulation, and number of GFRP shear grids by comparing the theoretical and experimental values. The failure modes of the ICSWPs were compared to investigate the effect of bonds according to the load direction and type of insulation. Bonds based on insulation absorptiveness were effective to result in the composite behavior of ICSWP under positive loading tests only, while bonds based on insulation surface roughness were effective under both positive and negative loading tests. Therefore, the composite behavior based on surface roughness can be applied to the calculation of the design strength of ICSWPs with continuous GFRP shear connectors.

  12. Development of a Personalized Model for Pressure Ulcer Prevention Acutely Following Spinal Cord Injury: Biomarkers of Muscle Composition and Resilience

    Science.gov (United States)

    2016-10-01

    Model for Pressure Ulcer Prevention Acutely Following Spinal Cord Injury : Biomarkers of Muscle Composition and Resilience 5a. CONTRACT NUMBER 5b...with acute spinal cord injury at risk of pressure ulcers. This project will investigate potential linkages between skeletal muscle tissue...AWARD NUMBER: W81XWH-14-1-0618 TITLE: Development of a Personalized Model for Pressure Ulcer Prevention Acutely Following Spinal Cord Injury

  13. A PRESSURE ULCER AND FALL RATE QUALITY COMPOSITE INDEX FOR ACUTE CARE UNITS: A MEASURE DEVELOPMENT STUDY

    Science.gov (United States)

    Jayawardhana, Ananda; Burman, Mary E.; Dunton, Nancy E.; Staggs, Vincent S.; Bergquist-Beringer, Sandra; Gajewski, Byron J.

    2016-01-01

    Background Composite indices are single measures that combine the strengths of two or more individual measures and provide broader, easy-to-use measures for evaluation of provider performance and comparisons across units and hospitals to support quality improvement. Objective The study objective was to develop a unit-level inpatient composite nursing care quality performance index – the Pressure Ulcer and Fall Rate Quality Composite Index. Design Two-phase measure development study. Settings 5,144 patient care units in 857 United States hospitals participating in the National Database of Nursing Quality Indictors® during the year 2013. Methods The Pressure Ulcer and Fall Rate Quality Composite Index was developed in two phases. In Phase 1 the formula was generated using a utility function and generalized penalty analysis. Experts with experience in healthcare quality measurement provided the point of indicator equivalence. In Phase 2 initial validity evidence was gathered based on hypothesized relationships between the Pressure Ulcer and Fall Rate Quality Composite Index and other variables using two-level (unit, hospital) hierarchical linear mixed modeling. Results The Pressure Ulcer and Fall Rate Quality Composite Index = 100 − PUR − FR, where PUR is pressure ulcer rate and FR is total fall rate. Higher scores indicate better quality. Bland-Altman plots demonstrated agreement between pairs of experts and provided evidence for inter-rater reliability of the formula. The validation process demonstrated that higher registered nurse skill mix, higher percent of registered nurses with a baccalaureate in nursing or higher degree, higher percent of registered nurses with national specialty certification, and lower percent of hours supplied by agency staff were significantly associated with higher Pressure Ulcer and Fall Rate Quality Composite Index scores. Higher percentages of unit patients at risk for a hospital-acquired pressure ulcer and higher unit rates of

  14. High-Pressure Synthesis of Metal-Ceramic Nano-Composites

    Science.gov (United States)

    Gierlotka, S.; Palosz, B.; Ekimov, E.; Grzanka, E.; Stelmakh, S.; Lojkowski, W.; Bismayer, U.; Palosz, W.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    The major problems in fabrication of nano-crystal line materials form nano-powders are: (1), coarsening of the initial nano-size grains, (2), insufficient densification (high concentration of pores), and, (3), conversion of diamond into graphite (for diamond-based ceramics). We have developed a novel technique of the synthesis of nano-composite materials applying very high (up to about 10 GPa) pressures. In this technique, one component is pre-compacted and placed next to another having a lower melting point temperature. The whole sample is pressed and the temperature raised above the melting point of the second component, what results in the melt getting pressed into the (nano-size) pores of the compact. Upon subsequent crystallization the melt forms the second nanophase. The process is fast, on the order of seconds, and the temperatures are relatively low what prevents, or at least significantly reduces coarsening of the starting nanophase grains. Also, conversion of diamond into graphite can be prevented. The technique allows for control of the final product properties through a proper selection of (1) the initial compact density and grain size, (2) chemical composition of the source, and (3) the temperature and pressure of the process. The application of the technique to the synthesis of SiC and diamond with Si, Ge, and different metals. Results of the in-situ investigation of the synthesis process by synchrotron X-ray diffraction technique will be presented.

  15. Pressure impact of autoclave treatment on water sorption and pectin composition of flax cellulosic-fibres.

    Science.gov (United States)

    Alix, S; Colasse, L; Morvan, C; Lebrun, L; Marais, S

    2014-02-15

    The tensile properties of flax fibres might permit them to be used in composites as reinforcement in organic resin, as long as their mechanical properties are reproducible and their water sorption are reduced. In this study, to minimise the variability of mechanical properties, several samples of flax fibres were blended as a non-woven fabric. In order to reduce the water absorption of this non-woven technical fibres, an autoclave treatment was performed which was expected to remove the pectins and then to reduce the water sorption on their negative charges. The impact of autoclave pressure (0.5, 1 and 2 bars) on water sorption was investigated by using a gravimetric static equilibrium method. The Park model based on the three sorption modes: Langmuir, Henry's law and clustering, was successfully used to simulate the experimental sorption data. The lowest pressure treatments impacted only the Langmuir contribution while the 2 bar autoclave-treatment positively impacted the water resistance in the core of fibres by reducing Henry's absorption rate. This was shown to be related to the chemical modifications at the surface and in the core of fibres. A schematic model is presented relating the water sorption and the pectic composition of the fabric. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Temperature-Compensated Force/Pressure Sensor Based on Multi-Walled Carbon Nanotube Epoxy Composites

    Directory of Open Access Journals (Sweden)

    Nghia Trong Dinh

    2015-05-01

    Full Text Available In this study, we propose a multi-walled carbon nanotube epoxy composite sensor for force and pressure sensing in the range of 50 N–2 kN. A manufacturing procedure, including material preparation and deposition techniques, is proposed. The electrode dimensions and the layer thickness were optimized by the finite element method. Temperature compensation is realized by four nanocomposites elements, where only two elements are exposed to the measurand. In order to investigate the influence of the filler contents, samples with different compositions were prepared and investigated. Additionally, the specimens are characterized by cyclical and stepped force/pressure loads or at defined temperatures. The results show that the choice of the filler content should meet a compromise between sensitivity, temperature influence and noise behavior. At constant temperature, a force of at least 50N can be resolved. The measurement error due to the temperature influence is 150N in a temperature range of –20°C–50°C.

  17. High pressure synthesis of novel, zeolite based nano-composite materials

    Science.gov (United States)

    Santoro, Mario

    2013-06-01

    Meso/micro-porous solids such as zeolites are complex materials exhibiting an impressive range of applications, including molecular sieve, gas storage, catalysis, electronics and photonics. We used these materials, particularly non catalytic zeolites in an entirely different fashion. In fact, we performed high pressure (0.5-30 GPa) chemical reactions of simple molecules on a sub-nanometer scale in the channels of a pure SiO2 zeolite, silicalite to obtain unique nano-composite materials with drastically modified physical and chemical properties. Our material investigations are based on a combination of X-ray diffraction and optical spectroscopy techniques in the diamond anvil cell. I will first briefly show how silicalite can be easily filled by simple molecules such as Ar, CO2 and C2H4 among others from the fluid phase at high pressures, and how this efficient filling removes the well known pressure induced amorphization of the silica framework (Haines et al., JACS 2010). I will then present on a silicon carbonate crystalline phase synthesized by reacting silicalite and molecular CO2 that fills the nano-pores, at 18-26 GPa and 600-980 K; after the synthesis the compound is temperature quenched and it results to be slightly metastable at room conditions (Santoro et al., PNAS 2011). On the other hand, a stable at room condition spectacular crystalline nano-composite is obtained by photo-polymerizing ethylene at 0.5-1.5 GPa under UV (351-364 nm) irradiation in the channels of silicalite (Santoro et al., Nat. Commun, in press 2013). For this composite we obtained a structure with single polyethylene chains adapting very well to the confining channels, which results in significant increases in bulk modulus and density, and the thermal expansion coefficient changes sign from negative to positive with respect to the original silicalite host. Mechanical properties may thus be tuned by varying the amount of polymerized ethylene. We then think our findings could allow the

  18. Explosion of gaseous ethylene-air mixtures in closed cylindrical vessels with central ignition.

    Science.gov (United States)

    Movileanu, Codina; Gosa, Vasile; Razus, Domnina

    2012-10-15

    Explosions of gaseous ethylene-air mixtures with various concentrations between 3.0 and 14.0 vol.% and initial pressures between 0.20 and 1.10 bar were experimentally investigated at ambient initial temperature, using several elongated cylindrical vessels with length to diameter ratio between 1.0 and 2.4. The maximum explosion pressures p(max), the explosion times θ(max), the maximum rates of pressure rise, (dp/dt)(max) and the severity factors of centrally ignited explosions K(G) are examined in comparison with similar data obtained in a spherical vessel. The measured deflagration indices are strongly influenced by the length to diameter ratio of the vessels, initial pressure and composition of the flammable mixtures. Even when important heat losses are present, linear correlations p(max)=f(p(0)) and (dp/dt)(max)=f(p(0)) were found for all examined fuel-air mixtures, in all closed vessels. The heat losses appearing in the last stage of explosions occurring in asymmetrical vessels were estimated from the differences between the experimental and adiabatic maximum explosion pressures. These heat losses are higher when the asymmetry ratio L/D is higher and were found to depend linearly on the initial pressure. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. The determinants of fishing vessel accident severity.

    Science.gov (United States)

    Jin, Di

    2014-05-01

    The study examines the determinants of fishing vessel accident severity in the Northeastern United States using vessel accident data from the U.S. Coast Guard for 2001-2008. Vessel damage and crew injury severity equations were estimated separately utilizing the ordered probit model. The results suggest that fishing vessel accident severity is significantly affected by several types of accidents. Vessel damage severity is positively associated with loss of stability, sinking, daytime wind speed, vessel age, and distance to shore. Vessel damage severity is negatively associated with vessel size and daytime sea level pressure. Crew injury severity is also positively related to the loss of vessel stability and sinking. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Driving force for indentation cracking in glass: composition, pressure and temperature dependence

    Science.gov (United States)

    Rouxel, Tanguy

    2015-01-01

    The occurrence of damage at the surface of glass parts caused by sharp contact loading is a major issue for glass makers, suppliers and end-users. Yet, it is still a poorly understood problem from the viewpoints both of glass science and solid mechanics. Different microcracking patterns are observed at indentation sites depending on the glass composition and indentation cracks may form during both the loading and the unloading stages. Besides, we do not know much about the fracture toughness of glass and its composition dependence, so that setting a criterion for crack initiation and predicting the extent of the damage yet remain out of reach. In this study, by comparison of the behaviour of glasses from very different chemical systems and by identifying experimentally the individual contributions of the different rheological processes leading to the formation of the imprint—namely elasticity, densification and shear flow—we obtain a fairly straightforward prediction of the type and extent of the microcracks which will most likely form, depending on the physical properties of the glass. Finally, some guidelines to reduce the driving force for microcracking are proposed in the light of the effects of composition, temperature and pressure, and the areas for further research are briefly discussed. PMID:25713446

  1. Very Versatile Vessel

    Science.gov (United States)

    2009-09-01

    data. This source provides information on aluminum hydrofoil vessels without the added weight of foil structures. The composite armor around the...seating compartment. The sides should also limit wave splash on the deck. The freeboard should contribute reserve buoyancy , increasing large-angle and...Resistance, Powering, and Propulsion Savitsky’s Method Since model testing data or other reliable performance data was unavailable for the proposed

  2. Studies on formation and structures of ultrafine Cu precipitates in Fe-Cu model alloys for reactor pressure vessel steels using positron quantum dot confinement in the precipitates by their positron affinity. JAERI's nuclear research promotion program, H11-034 (Contract research)

    CERN Document Server

    Hasegawa, M; Suzuki, M; Tang, Z; Yubuta, K

    2003-01-01

    Positron annihilation experiments on Fe-Cu model dilute alloys of nuclear reactor pressure vessel (RPV) steels have been performed after neutron irradiation in JMTR. Nanovoids whose inner surfaces were covered by Cu atoms were clearly observed. The nanovoids transformed to ultrafine Cu precipitates by dissociating their vacancies after annealing at around 400degC. The nanovoids and the ultrafine Cu precipitates are strongly suggested to be responsible for irradiation-induced embrittlement of RPV steels. Effects of Ni, Mn and P addition on the nanovoid and Cu precipitate formations were also studied. The nanovoid formation was enhanced by Ni and P, but suppressed by Mn. The Cu precipitates after annealing around 400degC were almost free from these doping elements and hence were pure Cu in the chemical composition. Furthermore the Fermi surface of the 'embedded' Cu precipitates with a body centered cubic crystal structure was obtained from two dimensional angular correlation of annihilation radiation (2D-ACAR) ...

  3. Completion of the dismantling, cutting and packaging for final disposal of the MZFR reactor pressure vessel including internals; Abschluss der vollstaendigen Demontage, Zerlegung und endlagergerechten Verpackung des 400 t schweren MZFR-Reaktordruckbehaelters incl. Einbauten

    Energy Technology Data Exchange (ETDEWEB)

    Prechtl, E.; Eisenmann, B.; Weis, A. [Forschungszentrum Karlsruhe GmbH (DE). Hauptabt. Projekte (HAP-MZFR); Suessdorf, W. [Studsvik GmbH und Co. KG, Pforzheim (Germany); Loeb, A.; Stanke, D.; Thoma, M. [NIS Ingenieurgesellschaft mbH, Alzenau (Germany)

    2008-07-01

    The test reactor 400 tons MZFR reactor pressure vessel has been dismantled, dissected and packaged for final disposal. The authors describe the initial situation of the reactor after 19 years of operation. The dismantling was complicated by the high radioactivity and the high contamination due to the constricted space in the building. In 1995/1996 remote cutting tools for hot components were not yet available. Established techniques were adapted and refined for the special purpose. The dissected vessel was packaged for final disposal in the final repository Konrad. The authors describe the dismantling concept including boundary conditions and general requirements, the implementation of the concept and experiences of the process including qualification and training of the personnel.

  4. Compositions of graphene materials with metal nanostructures and microstructures and methods of making and using including pressure sensors

    KAUST Repository

    Chen, Ye

    2017-01-26

    Composition comprising at least one graphene material and at least one metal. The metal can be in the form of nanoparticles as well as microflakes, including single crystal microflakes. The metal can be intercalated in the graphene sheets. The composition has high conductivity and flexibility. The composition can be made by a one-pot synthesis in which a graphene material precursor is converted to the graphene material, and the metal precursor is converted to the metal. A reducing solvent or dispersant such as NMP can be used. Devices made from the composition include a pressure sensor which has high sensitivity. Two two- dimension materials can be combined to form a hybrid material.

  5. Invasion of nitrite oxidizer dominated communities: interactions between propagule pressure and community composition

    DEFF Research Database (Denmark)

    Kinnunen, Marta; Dechesne, Arnaud; Albrechtsen, Hans-Jørgen

    Managing invasion of microbial communities by new members can be a powerful tool in microbial resource management. Abundant studies have examined how resource availability and resident community diversity affect invasion success. Yet, a more rigorous approach towards studying invasion would...... reported. The objective of this study was to determine the effect of propagule pressure on invasion success in microbial communities, shaped by varying degrees of stochasticity and determinism. The experimental system consisted of nitrite oxidizing bacterial enrichments, developed in replicate flow......-through biofilm reactors using drinking water as inoculum and continuous feeding with nitrite a sole energy source. Different nitrite loading rates were applied, as these were previously shown to influence nitrifying guild composition and stochasticity [1]. After 6 weeks, the reactors were invaded for 24 hours...

  6. Progressive Fracture of Laminated Fiber-Reinforced Composite Stiffened Plate Under Pressure

    Science.gov (United States)

    Gotsis, Pascalis K.; Abdi, Frank; Chamis, Christos C.; Tsouros, Konstantinos

    2007-01-01

    S-Glass/epoxy laminated fiber-reinforced composite stiffened plate structure with laminate configuration (0/90)5 was simulated to investigate damage and fracture progression, under uniform pressure. For comparison reasons a simple plate was examined, in addition with the stiffened plate. An integrated computer code was used for the simulation. The damage initiation began with matrix failure in tension, continuous with damage and/or fracture progression as a result of additional matrix failure and fiber fracture and followed by additional interply delamination. Fracture through the thickness began when the damage accumulation was 90%. After that stage, the cracks propagate rapidly and the structures collapse. The collapse load for the simple plate is 21.57 MPa (3120 psi) and for the stiffened plate 25.24 MPa (3660 psi).

  7. Testing of a Stitched Composite Large-Scale Multi-Bay Pressure Box

    Science.gov (United States)

    Jegley, Dawn; Rouse, Marshall; Przekop, Adam; Lovejoy, Andrew

    2016-01-01

    NASA has created the Environmentally Responsible Aviation (ERA) Project to develop technologies to reduce aviation's impact on the environment. A critical aspect of this pursuit is the development of a lighter, more robust airframe to enable the introduction of unconventional aircraft configurations. NASA and The Boeing Company have worked together to develop a structural concept that is lightweight and an advancement beyond state-of-the-art composite structures. The Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) is an integrally stiffened panel design where elements are stitched together. The PRSEUS concept is designed to maintain residual load carrying capabilities under a variety of damage scenarios. A series of building block tests were evaluated to explore the fundamental assumptions related to the capability and advantages of PRSEUS panels. The final step in the building block series is an 80%-scale pressure box representing a portion of the center section of a Hybrid Wing Body (HWB) transport aircraft. The testing of this article under maneuver load and internal pressure load conditions is the subject of this paper. The experimental evaluation of this article, along with the other building block tests and the accompanying analyses, has demonstrated the viability of a PRSEUS center body for the HWB vehicle. Additionally, much of the development effort is also applicable to traditional tube-and-wing aircraft, advanced aircraft configurations, and other structures where weight and through-the-thickness strength are design considerations.

  8. Imparting Barely Visible Impact Damage to a Stitched Composite Large-Scale Pressure Box

    Science.gov (United States)

    Lovejoy, Andrew E.; Przekop, Adam

    2016-01-01

    The Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) is a concept that was developed by The Boeing Company to address the complex structural design aspects associated with a pressurized hybrid wing body (HWB) aircraft configuration, which has been a focus of the NASA Environmentally Responsible Aviation Project. The NASA-Boeing structural development for the HWB aircraft culminated in testing of the multi-bay box, which is an 80%-scale representation of the pressurized center-body section. This structure was tested in the NASA Langley Research Center Combined Loads Test System facility. As part of this testing, barely visible impact damage was imparted to the interior and exterior of the test article to demonstrate compliance with a condition representative of the requirements for Category 1 damaged composite structure as defined by the Federal Aviation Regulations. Interior impacts were imparted using an existing spring-loaded impactor, while the exterior impacts were imparted using a newly designed, gravity-driven impactor. This paper describes the impacts to the test article, and the design of the gravitydriven guided-weight impactor. The guided-weight impactor proved to be a very reliable method to impart barely visible impact damage in locations which are not easily accessible for a traditional drop-weight impactor, while at the same time having the capability to be highly configurable for use on other aircraft structures.

  9. The compositions of minerals within high pressure tectonic blocks from Horse Mountain, Northern California

    Energy Technology Data Exchange (ETDEWEB)

    Gilliam, C.E. (Mount Holyoke College, South Hadley, MA (United States). Geology Dept.)

    1993-03-01

    High pressure metamorphic blocks occur within serpentinite between the South Fork Mountain Schist and the Coast Range Fault, Humboldt Co., Northern California. Samples from three of these blocks were studied by petrographic techniques and quantitatively analyzed using the energy dispersive spectrometer on out scanning electron microscope. The mineral assemblages for three samples are as follows: WC86-7-3 contains omphacite (jd53, di36, hd11), pumpellyite, and relic igneous clinopyroxene. WC86-9-3 contains titanite, epidote chlorite, pumpellyite, and relic clinopyroxene. WC86-18-3 contains garnet, lawsonite, glaucophane, albite, chlorite, pumpellyite, minor quartz, and relic clinopyroxene. All samples contain relic clinopyroxene that, in the case of SC86-7-3, acts as a nucleus for omphacite growth. When present in cross cutting veins, omphacite has both radiating fibrous and blocky textures. Some epidote, titanite, clinopyroxene and pumpellyite were too fine to identify optically as well, but occur in the ground mass. Large grains of euhedral glaucophane, (Na[sub 2.0] Ca[sub .2])(Mg[sub 1.3] Fe[sub 2.0] Al[sub 1.7])Si[sub 8.0] O[sub 22] (OH)[sub 2], and garnet, (alm 33, pyO, sp30, gr37), containing relic ( ) clinopyroxene, glaucophane, and albite inclusions, were present in WC86-18-3. The high SiO[sub 2] and low TiO[sub 2] relative to Al[sub 2]O[sub 3] in relic clinopyroxene indicates a non-alkaline tholeiitic protolith. Omphacite compositions correspond to the type IV blueschist typical of the Franciscan Complex and constrain the pressures of metamorphism to be approximately 9 kb while lawsonite in WC86-18-3 implies a temperature below 450C. These observations indicate that the blocks are derived from subducted material that underwent metamorphism in a low temperature, high pressure setting. The process of their exhumation remains a mystery.

  10. Coefficient of Friction Measurements for Thermoplastics and Fibre Composites Under Low Sliding Velocity and High Pressure

    DEFF Research Database (Denmark)

    Poulios, Konstantinos; Svendsen, Gustav Winther; Hiller, Jochen

    2013-01-01

    Friction materials for typical brake applications are normally designed considering thermal stability as the major performance criterion. There are, however, brake applications with very limited sliding velocities, where the generated heat is insignificant. In such cases it is possible that frict......Friction materials for typical brake applications are normally designed considering thermal stability as the major performance criterion. There are, however, brake applications with very limited sliding velocities, where the generated heat is insignificant. In such cases it is possible...... that friction materials which are untypical for brake applications, like thermoplastics and fibre composites, can offer superior performance in terms of braking torque, wear resistance and cost than typical brake linings. In this paper coefficient of friction measurements for various thermoplastic and fibre...... composite materials running against a steel surface are presented. All tests were carried out on a pinon-disc test-rig in reciprocating operation at a fixed sliding speed and various pressure levels for both dry and grease lubricated conditions. Moreover, a generic theoretical framework is introduced...

  11. Blood pressure, pulse rate, and rhythm measurement using ionic polymer-metal composite sensors

    Science.gov (United States)

    Keshavarzi, Amid; Shahinpoor, Mohsen; Kim, Kwang J.; Lantz, Jeffrey W.

    1999-05-01

    The need for more enhanced blood pressure (BP), pulse rate and rhythm senors has given rise to the possibility of using ionic polymer-metal composites (IPMCs) sensors. In this study we propose to use the IPMC sensors to measure systolic and diastolic BP, pulse rate and rhythm. The proposed IPMC sensors take advantage of the endo-ionic mobility within the polymer- metal composite by converting normal and shear load inputs into an induced voltage output across the thickness of the IPMC sensor. The fabricated IPMC sensors are suitable to be installed on the inner surface of a cuff and, therefore, both systolic and diastolic BP, pulse rate, and rhythm can be measured. An added benefit is the ability of measuring 'pulse rhythm' which give a more amplified look at heart irregularities which a typical pulse rate sensor is unable to show. Our data shows IPMC sensors can produce consistent and reliable BP readings, pulse rate, and rhythm. Typically, a linear relationship between applied maximum load and induced maximum voltage was obtained. This result can be easily translated into good BP reading.

  12. Effects of Hot-Pressure Extraction Time on Composition and Gelatin Properties of Chicken Bone Extracts.

    Science.gov (United States)

    Yue, Jian-Ying; Wang, Jin-Zhi; Zhang, Chun-Hui; Jia, Wei; Li, Xia; Sun, Zhen

    2017-05-01

    Hot-pressure extraction was utilized in this study to extract proteins from chicken bones at 130 °C. The obtained extracts were further used to prepare gelatin gels. Results demonstrated that the extraction time can significantly affect the composition of the chicken bone extracts (P 30 KDa was only visible in the extracts collected between 40 and 60 min. The highest contents of hydroxyproline, imino acids, and hydrophobic amino acids were all achieved in the chicken bone extracts after 120 min of extraction, being 3.9, 7.7, and 16.0 mg/g, respectively. The prepared gelatin properties were evaluated in terms of viscosity, storage and loss modulus, stability, gel strength, and their microstructures. Results indicated that gelatins made from chicken bone extracts of 20, 40, and 60 min extraction had better properties compared to that of 90 and 120 min. Significant correlations were identified between gelatin's composition and properties (P gelatin's properties. This study illustrated a promising and natural way to obtain edible gelatins from chicken bones. © 2017 Institute of Food Technologists®.

  13. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... which blood flows through blood vessels (arteries) at higher than normal pressures. Measuring Blood Pressure Blood pressure ... blood pressure are defined as having blood pressures higher than 120/80 mmHg. The following table outlines ...

  14. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... Back To Health Topics / High Blood Pressure High Blood Pressure Also known as Hypertension Leer en español ... vessels (arteries) at higher than normal pressures. Measuring Blood Pressure Blood pressure is the force of blood ...

  15. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... Back To Health Topics / High Blood Pressure High Blood Pressure Also known as Hypertension See also Information ... vessels (arteries) at higher than normal pressures. Measuring Blood Pressure Blood pressure is the force of blood ...

  16. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... Back To Health Topics / High Blood Pressure High Blood Pressure Also known as Hypertension See also Information for ... vessels (arteries) at higher than normal pressures. Measuring Blood Pressure Blood pressure is the force of blood pushing ...

  17. The dynamics of 24-hour ambulatory blood pressure monitoring parameters, subclinical damage and endothelial function of vessels in patients with arterial hypertension and chronic obstructive pulmonary disease treated with S-amlodipine, Nebivolol and Enala

    Directory of Open Access Journals (Sweden)

    V. N. Seredyuk

    2017-02-01

    Full Text Available Aim of the research was to investigate additional prescription of S-amlodipine or Nebivolol to Enalapril treatment on the 24-h blood pressure monitoring (BPM parameters, subclinical damage and endothelial function of vessels, and to make of proposing of treatment of the arterial hypertension (AH and chronic obstructive pulmonary disease (COPD. Material and Methods. 95 patients (64 males and 31 females with AH II stage and COPD III stage in remission were observed. The average age was (54.7 ± 9.5 years. The 24-h BPM by devices “АВРМ-04” (“Meditech”, Hungary and “EBPM” (“Innomed”, Hungary was provided to all patients. Stiffness index of aorta (ASI was evaluated by Yu.M. Sirenko and G.D. Radchenko method (2009. Reactive hyperemia test was performed by D.S. Celermajer, K.E. Sorensen et al. method (1992. Computer spirography was made by “SpiroCom” (HAI-Medica, Ukraine. The serum level of endothelin -1 (ET 1 was detected by ELISA (“Peninsula Laboratories”, USA. Results. It was established, that additional prescription of S-amlodipine or Nebivolol to Enalapril and standard therapy of COPD during 6 month had strong antihypertensive effect, normalized 24-hours blood pressure profile, decreased blood pressure loading and subclinical damage indices, such as: pulse blood pressure, heart rate and ASI. Conclusion. Treatment of patients with AH and COPD should be differentiated. In case of prevalence of the clinical, laboratory and instrumental signs of broncho-obsctructive syndrome, presence of subclinical damages and elastic qualities of vessels and endothelial dysfunction in patients with AH and COPD S-amlodipine should be prescribed additionally to Enalapril and basic therapy of CODP. In case of AH and COPD with hypersympatheticotonia, sings of blood pressure loading, increase of pulse BP and tachycardia beta-blocker Nebivolol should be added to the treatment.

  18. Effect of impregnation pressure and time on the porosity, structure and properties of polyacrylonitrile-fiber based carbon composites

    Science.gov (United States)

    Venugopalan, Ramani; Roy, Mainak; Thomas, Susy; Patra, A. K.; Sathiyamoorthy, D.; Tyagi, A. K.

    2013-02-01

    Carbon-carbon composites may find applications in critical parts of advanced nuclear reactors. A series of carbon-carbon composites were prepared using polyacrylonitrile (PAN) based carbon fibers. The materials were densified by impregnating two-dimensional (2D) preforms with liquid phenol formaldehyde resin at different pressures and for different periods of time and then carbonizing those by slowly heating at 1000 °C. Effects of the processing parameters on the structure of the composites were extensively studied. The study showed conclusively that open porosity decreased with increasing impregnation pressure, whereas impregnation time had lesser effect. Matrix-resin bonding also improved at higher pressure. d002 spacing decreased and ordering along c-axis increased with concomitant increase in sp2-carbon fraction at higher impregnation pressures. The fiber reinforced composites exhibited short range ordering of carbon atoms and satisfied structural conditions (d002 values) of amorphous carbon according to the turbostratic model for non-graphitic carbon materials. The composites had pellet-density of ˜85% of the theoretical value, low thermal expansion and negligible neutron-poisoning. They maintained structural integrity and retained disordered nature even on heat-treatment at ca. 1800 °C.

  19. Development of advanced manufacturing technologies for low cost hydrogen storage vessels

    Energy Technology Data Exchange (ETDEWEB)

    Leavitt, Mark [Quantum Fuel Systems Technologies Worldwide, Inc., Irvine, CA (United States); Lam, Patrick [Boeing Research and Technology (BR& T), Seattle, WA (United States)

    2014-12-29

    The U.S. Department of Energy (DOE) defined a need for low-cost gaseous hydrogen storage vessels at 700 bar to support cost goals aimed at 500,000 units per year. Existing filament winding processes produce a pressure vessel that is structurally inefficient, requiring more carbon fiber for manufacturing reasons, than would otherwise be necessary. Carbon fiber is the greatest cost driver in building a hydrogen pressure vessel. The objective of this project is to develop new methods for manufacturing Type IV pressure vessels for hydrogen storage with the purpose of lowering the overall product cost through an innovative hybrid process of optimizing composite usage by combining traditional filament winding (FW) and advanced fiber placement (AFP) techniques. A numbers of vessels were manufactured in this project. The latest vessel design passed all the critical tests on the hybrid design per European Commission (EC) 79-2009 standard except the extreme temperature cycle test. The tests passed include burst test, cycle test, accelerated stress rupture test and drop test. It was discovered the location where AFP and FW overlap for load transfer could be weakened during hydraulic cycling at 85°C. To design a vessel that passed these tests, the in-house modeling software was updated to add capability to start and stop fiber layers to simulate the AFP process. The original in-house software was developed for filament winding only. Alternative fiber was also investigated in this project, but the added mass impacted the vessel cost negatively due to the lower performance from the alternative fiber. Overall the project was a success to show the hybrid design is a viable solution to reduce fiber usage, thus driving down the cost of fuel storage vessels. Based on DOE’s baseline vessel size of 147.3L and 91kg, the 129L vessel (scaled to DOE baseline) in this project shows a 32% composite savings and 20% cost savings when comparing Vessel 15 hybrid design and the Quantum

  20. Tribological Properties of AlSi11-SiCp Composite Castings Produced by Pressure Die Casting Method

    Directory of Open Access Journals (Sweden)

    Konopka Z.

    2014-08-01

    Full Text Available The measurement results concerning the abrasive wear of AlSi11-SiC particles composites are presented in paper. The method of preparing a composite slurry composed of AlSi11 alloy matrix and 10, 20% vol.% of SiC particles, as well as the method of its high-pressure die casting was described. Composite slurry was injected into metal mould of cold chamber pressure die cast machine and castings were produced at various values of the piston velocity in the second stage of injection, diverse intensification pressure values, and various injection gate width values. Very good uniform arrangement of SiC particles in volume composite matrix was observed and these results were publicated early in this journal. The kinetics of abrasive wear and correlation with SiC particles arrangement in composite matrix were presented. Better wear resistance of composite was observed in comparison with aluminium alloy. Very strong linear correlation between abrasive wear and particle arrangement was observed. The conclusion gives the analysis and the interpretation of the obtained results.

  1. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... weakens and damages your blood vessels, which can lead to complications . Types of High Blood Pressure There ... Angiotensin narrows or constricts blood vessels, which can lead to an increase in blood pressure. Aldosterone controls ...

  2. Long-term mountain tundra composition's responses to grazing pressure in the context of environmental changes

    Science.gov (United States)

    Saccone, Patrick; Pyykkonen, Tuija; Eskelinen, Anu; Virtanen, Risto

    2013-04-01

    Strong changes in northern tundra in response to climate changes are expected and in particular an increasing shrubiness. However, global changes contain not only warming or shifts in snow-cover but also changes in land-use, e.g. for arctic low productive ecosystems changes in grazing pressure. Grazing could also represent an important driver of future Arctic tundra communities. However, the relative importance of biotic and abiotic drivers of plant communities' composition remains largely unknown, in particular because short-term experiments provided to conflicting evidences. Here, we present the results from a long-term (23 years) experiment set up in 1989 at Kilpisjärvi in the north-western Finnish Lapland. The experiment consisted in the transplantation of twenty 40x50 cm blocks of Vaccinium myrtillus heath including 5-10 cm thick soil layer from a 660 m.a.s.l. dry slope to a snowbed 150m higher in elevation containing dry and wet sites. We considered the transplantation at higher altitude in snowbed conditions an increase in harsher conditions (shorter growing season, lower productivity). Half of the transplanted blocks were protected from herbivores and the percentage cover of each plant species was estimated in mid-august 2012 from a central 12.5 x12.5 cm area in each block. Our results showed that the dominance of the shrub V. myrtillus was strongly reduced as response to transplantation to snowbed. Consequently the competitive pressure also decreased and allowed an increase of the species richness. Soil moisture differences between installation locations induced divergence in plant communities' composition allowing the increase in abundance of subordinate species as bryophytes and graminoids in wet and dry sites respectively. Excluding herbivory, some species assumed high dominance reducing the community diversity. In the wet exclosures, quarter of the surface was covered by a moss and V. myrtillus co-dominated. The strongest changes occurred in dry

  3. Nonlinear Finite Element Analysis of a Composite Non-Cylindrical Pressurized Aircraft Fuselage Structure

    Science.gov (United States)

    Przekop, Adam; Wu, Hsi-Yung T.; Shaw, Peter

    2014-01-01

    The Environmentally Responsible Aviation Project aims to develop aircraft technologies enabling significant fuel burn and community noise reductions. Small incremental changes to the conventional metallic alloy-based 'tube and wing' configuration are not sufficient to achieve the desired metrics. One of the airframe concepts that might dramatically improve aircraft performance is a composite-based hybrid wing body configuration. Such a concept, however, presents inherent challenges stemming from, among other factors, the necessity to transfer wing loads through the entire center fuselage section which accommodates a pressurized cabin confined by flat or nearly flat panels. This paper discusses a nonlinear finite element analysis of a large-scale test article being developed to demonstrate that the Pultruded Rod Stitched Efficient Unitized Structure concept can meet these challenging demands of the next generation airframes. There are specific reasons why geometrically nonlinear analysis may be warranted for the hybrid wing body flat panel structure. In general, for sufficiently high internal pressure and/or mechanical loading, energy related to the in-plane strain may become significant relative to the bending strain energy, particularly in thin-walled areas such as the minimum gage skin extensively used in the structure under analysis. To account for this effect, a geometrically nonlinear strain-displacement relationship is needed to properly couple large out-of-plane and in-plane deformations. Depending on the loading, this nonlinear coupling mechanism manifests itself in a distinct manner in compression- and tension-dominated sections of the structure. Under significant compression, nonlinear analysis is needed to accurately predict loss of stability and postbuckled deformation. Under significant tension, the nonlinear effects account for suppression of the out-of-plane deformation due to in-plane stretching. By comparing the present results with the previously

  4. The Behavior of a Stitched Composite Large-Scale Multi-Bay Pressure Box

    Science.gov (United States)

    Jegley, Dawn C.; Rouse, Marshall; Przekop, Adam; Lovejoy, Andrew E.

    2016-01-01

    NASA has created the Environmentally Responsible Aviation (ERA) Project to develop technologies to reduce impact of aviation on the environment. A critical aspect of this pursuit is the development of a lighter, more robust airframe to enable the introduction of unconventional aircraft configurations. NASA and The Boeing Company have worked together to develop a structural concept that is lightweight and an advancement beyond state-of-the-art composite structures. The Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) is an integrally stiffened panel design where elements are stitched together and designed to maintain residual load-carrying capabilities under a variety of damage scenarios. With the PRSEUS concept, through-the-thickness stitches are applied through dry fabric prior to resin infusion, and replace fasteners throughout each integral panel. Through-the-thickness reinforcement at discontinuities, such as along flange edges, has been shown to suppress delamination and turn cracks, which expands the design space and leads to lighter designs. The pultruded rod provides stiffening away from the more vulnerable skin surface and improves bending stiffness. A series of building block tests were evaluated to explore the fundamental assumptions related to the capability and advantages of PRSEUS panels. The final step in the building block series of tests is an 80%-scale pressure box representing a portion of the center section of a Hybrid Wing Body (HWB) transport aircraft. The testing of this test article under maneuver and internal pressure loading conditions is the subject of this paper. The experimental evaluation of this article, along with the other building block tests and the accompanying analyses, has demonstrated the viability of a PRSEUS center body for the HWB vehicle. Additionally, much of the development effort is also applicable to traditional tube-and-wing aircraft, advanced aircraft configurations, and other structures where weight and

  5. Faculty Composition in Four-Year Institutions: The Role of Pressures, Values, and Organizational Processes in Academic Decision-Making

    Science.gov (United States)

    Kezar, Adrianna; Gehrke, Sean

    2016-01-01

    This study broadens our understanding of conditions that shape faculty composition in higher education. We surveyed academic deans to evaluate their views on the professoriate, values, pressures, and practices pertaining to the use of non-tenure-track faculty (NTTF). We utilized [ordinary-least-squares] OLS regression to test a model for…

  6. The Role of Alloy Composition and T7 Heat Treatment in Enhancing Thermal Conductivity of Aluminum High Pressure Diecastings

    Science.gov (United States)

    Lumley, Roger N.; Deeva, Natalia; Larsen, Robert; Gembarovic, Jozef; Freeman, Joe

    2013-02-01

    The thermal conductivity of some common and experimental high pressure diecasting (HPDC) Al-Si-Cu alloys is evaluated. It is shown that the thermal conductivity of some compositions may be increased by more than 60 pct by utilizing T7 heat treatments. This may have substantial performance and cost benefits for applications where thermal management is a key design parameter.

  7. A Three-Dimensional Porous Conducting Polymer Composite with Ultralow Density and Highly Sensitive Pressure Sensing Properties

    Directory of Open Access Journals (Sweden)

    Jin-Dong Su

    2016-01-01

    Full Text Available An ultralight conducting polyaniline/SiC/polyacrylonitrile (PANI/SiC/PAN composite was fabricated by in situ polymerization of aniline monomer on the surface of fibers in SiC/PAN aerogel. The SiC/PAN aerogel was obtained by electrospinning, freeze-drying, and heat treatment. The ingredient, morphology, structure, and electrical properties of the aerogel before and after in situ polymerization were investigated by X-ray powder diffraction (XRD, Fourier transform infrared spectroscopy (FT-IR, scanning electron microscope (SEM, and voltage-current characteristic measurement. The thermostability of PANI/SiC/PAN composite was investigated by thermogravimetric analysis (TGA and electrical resistance measured at different temperatures. The density of the PANI/SiC/PAN composite was approximately 0.211 g cm−3, the porosity was 76.44%, and the conductivity was 0.013 S m−1. The pressure sensing properties were evaluated at room temperature. The electrical resistance of as-prepared sample decreased gradually with the increase of pressure. Furthermore, the pressure sensing process was reversible and the response time was short (about 1 s. This composite may have application in pressure sensor field.

  8. Thin-film composite pressure retarded osmosis membranes for sustainable power generation from salinity gradients.

    Science.gov (United States)

    Yip, Ngai Yin; Tiraferri, Alberto; Phillip, William A; Schiffman, Jessica D; Hoover, Laura A; Kim, Yu Chang; Elimelech, Menachem

    2011-05-15

    Pressure retarded osmosis has the potential to produce renewable energy from natural salinity gradients. This work presents the fabrication of thin-film composite membranes customized for high performance in pressure retarded osmosis. We also present the development of a theoretical model to predict the water flux in pressure retarded osmosis, from which we can predict the power density that can be achieved by a membrane. The model is the first to incorporate external concentration polarization, a performance limiting phenomenon that becomes significant for high-performance membranes. The fabricated membranes consist of a selective polyamide layer formed by interfacial polymerization on top of a polysulfone support layer made by phase separation. The highly porous support layer (structural parameter S = 349 μm), which minimizes internal concentration polarization, allows the transport properties of the active layer to be customized to enhance PRO performance. It is shown that a hand-cast membrane that balances permeability and selectivity (A = 5.81 L m(-2) h(-1) bar(-1), B = 0.88 L m(-2) h(-1)) is projected to achieve the highest potential peak power density of 10.0 W/m(2) for a river water feed solution and seawater draw solution. The outstanding performance of this membrane is attributed to the high water permeability of the active layer, coupled with a moderate salt permeability and the ability of the support layer to suppress the undesirable accumulation of leaked salt in the porous support. Membranes with greater selectivity (i.e., lower salt permeability, B = 0.16 L m(-2) h(-1)) suffered from a lower water permeability (A = 1.74 L m(-2) h(-1) bar(-1)) and would yield a lower peak power density of 6.1 W/m(2), while membranes with a higher permeability and lower selectivity (A = 7.55 L m(-2) h(-1) bar(-1), B = 5.45 L m(-2) h(-1)) performed poorly due to severe reverse salt permeation, resulting in a similar projected peak power density of 6.1 W/m(2).

  9. Thin-Film Composite Pressure Retarded Osmosis Membranes for Sustainable Power Generation from Salinity Gradients

    KAUST Repository

    Yip, Ngai Yin

    2011-05-15

    Pressure retarded osmosis has the potential to produce renewable energy from natural salinity gradients. This work presents the fabrication of thin-film composite membranes customized for high performance in pressure retarded osmosis. We also present the development of a theoretical model to predict the water flux in pressure retarded osmosis, from which we can predict the power density that can be achieved by a membrane. The model is the first to incorporate external concentration polarization, a performance limiting phenomenon that becomes significant for high-performance membranes. The fabricated membranes consist of a selective polyamide layer formed by interfacial polymerization on top of a polysulfone support layer made by phase separation. The highly porous support layer (structural parameter S = 349 μm), which minimizes internal concentration polarization, allows the transport properties of the active layer to be customized to enhance PRO performance. It is shown that a hand-cast membrane that balances permeability and selectivity (A = 5.81 L m-2 h-1 bar-1, B = 0.88 L m-2 h-1) is projected to achieve the highest potential peak power density of 10.0 W/m2 for a river water feed solution and seawater draw solution. The outstanding performance of this membrane is attributed to the high water permeability of the active layer, coupled with a moderate salt permeability and the ability of the support layer to suppress the undesirable accumulation of leaked salt in the porous support. Membranes with greater selectivity (i.e., lower salt permeability, B = 0.16 L m-2 h-1) suffered from a lower water permeability (A = 1.74 L m-2 h-1 bar-1) and would yield a lower peak power density of 6.1 W/m2, while membranes with a higher permeability and lower selectivity (A = 7.55 L m-2 h-1 bar-1, B = 5.45 L m-2 h-1) performed poorly due to severe reverse salt permeation, resulting in a similar projected peak power density of 6.1 W/m2. © 2011 American Chemical Society.

  10. Human Milk Composition and Preservation: Evaluation of High-pressure Processing as a Nonthermal Pasteurization Technology.

    Science.gov (United States)

    Sousa, Sílvia G; Delgadillo, Ivonne; Saraiva, Jorge A

    2016-01-01

    Human milk is seen not only as a food, but as a functional and dynamic biologic system. It provides nutrients, bioactive components, and immune factors, promoting adequate and healthy growth of newborn infants. When mothers cannot supply their children, donated breast milk is the nutrition recommended by the World Health Organization, as it is a better alternative than infant formula. However, because of the manner in which donor milk is handled in human milk banks (HMB) many of the properties ascribed to mother's own milk are diminished or destroyed. The major process responsible for these losses is Holder pasteurization. High-pressure processing (HPP) is a novel nonthermal pasteurization technology that is being increasingly applied in food industries worldwide, primarily as an alternative to thermal treatment. This is due to its capacity to inactivate microorganisms while preserving both nutritional and bioactive components of foods. This review describes human milk composition and preservation, and critically discusses HMB importance and practices, highlighting HPP as a potential nonthermal pasteurization technology for human milk preservation. HPP technology is described and the few currently existing studies of its effects in human milk are presented.

  11. Effect of atmospheric pressure plasma treatment condition on adhesion of ramie fibers to polypropylene for composite

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ying [College of Material and Textile Engineering, Jiaxing University, Jiaxing 314033 (China); Center for Plasma-Aided Manufacturing, Madison, WI 53706 (United States); School of Human Ecology, University of Wisconsin-Madison, Madison, WI 53706 (United States); Manolache, Sorin [Center for Plasma-Aided Manufacturing, Madison, WI 53706 (United States); US Forest Products Laboratory, Madison, WI 53726 (United States); Qiu, Yiping, E-mail: ypqiu@dhu.edu.cn [College of Textiles, Donghua University, Shanghai 201620 (China); Sarmadi, Majid, E-mail: majidsar@wisc.edu [Center for Plasma-Aided Manufacturing, Madison, WI 53706 (United States); School of Human Ecology, University of Wisconsin-Madison, Madison, WI 53706 (United States); Materials Science Program, University of Wisconsin-Madison, Madison, WI 53706 (United States)

    2016-02-28

    Graphical abstract: - Highlights: • The continuous ethanol flow technique can successfully modify ramie fiber surface with an increase in IFSS value up to 50%. • Response surface methodology was applied to design the plasma treatment parameters for ramie fiber modification. • The ethanol flow rate was the most influential treatment parameter in plasma modification process. - Abstract: In order to improve the interfacial adhesion between hydrophilic ramie fibers and hydrophobic polypropylene (PP) matrices, ramie fibers are modified by atmospheric pressure dielectric barrier discharge (DBD) plasma with our continuous ethanol flow technique in helium environment. A central composite design of experiments with different plasma processing parameter combinations (treatment current, treatment time and ethanol flow rate) is applied to find the most influential parameter and to obtain the best modification effect. Field emission scanning electron microscope (SEM) shows the roughened surfaces of ramie fibers from the treated groups due to plasma etching effect. Dynamic contact angle analysis (DCAA) demonstrates that the wettability of the treated fibers drastically decreases. Microbond pullout test shows that the interfacial shear strength (IFSS) between treated ramie fibers and PP matrices increases significantly. Residual gas analysis (RGA) confirms the creation of ethyl groups during plasma treatment. This study shows that our continuous ethanol flow technique is effective in the plasma modification process, during which the ethanol flow rate is the most influential parameter but all parameters have simultaneous influence on plasma modification effect of ramie fibers.

  12. Exchange of information on use of special high-pressure steels of irregular composition

    Energy Technology Data Exchange (ETDEWEB)

    Pier, M.

    1944-05-05

    Procedures to be followed in designation and usage of batches of steels with chemical compositions that did not quite match specifications are discussed. It seemed that because of the difficulties under which they were operating, steel works often supplied batches of such irregular steels. A special study commission set up to evaluate such steels used the following designations: suffix X (as in N 10 X) for irregular steel that was nevertheless fully usable in all usual applications for the particular type of steel involved, and suffix Z (as in N 0 Z) for irregular steel that should be limited to only the less demanding of the usual applications for the type of steel involved. For example, N 10 Z could be used for connecting pipes, including feed pipes, because they were not heated and did not have to withstand such high temperatures, or at most had to withstand up to 500/sup 0/C for short times (eg., 15 minute stretches). However, in hairpin tubes, N 10 Z should be used only for the less-heated positions designated for N 10, or else in the positions designated for N9. Finally, the report hinted that the designations N 10, N9, N8A, etc. represented a hierarchy of levels of quality in terms of appropriateness for use in high-pressure, high-temperature apparatus.

  13. Study on prestressed concrete reactor vessel structures. II-5: Crack analysis by three dimensional finite elements method of 1/20 multicavity type PCRV subjected to internal pressure

    Science.gov (United States)

    1978-01-01

    A three-dimensional finite elements analysis is reported of the nonlinear behavior of PCRV subjected to internal pressure by comparing calculated results with test results. As the first stage, an analysis considering the nonlinearity of cracking in concrete was attempted. As a result, it is found possible to make an analysis up to three times the design pressure (50 kg/sqcm), and calculated results agree well with test results.

  14. A Novel Method for Fabricating Wearable, Piezoresistive, and Pressure Sensors Based on Modified-Graphite/Polyurethane Composite Films

    Science.gov (United States)

    He, Yin; Li, Wei; Yang, Guilin; Liu, Hao; Lu, Junyu; Zheng, Tongtong; Li, Xiaojiu

    2017-01-01

    A wearable, low-cost, highly repeatable piezoresistive sensor was fabricated by the synthesis of modified-graphite and polyurethane (PU) composites and polydimethylsiloxane (PDMS). Graphite sheets functionalized by using a silane coupling agent (KH550) were distributed in PU/N,N-dimethylformamide (DMF) solution, which were then molded to modified-graphite/PU (MG/PU) composite films. Experimental results show that with increasing modified-graphite content, the tensile strength of the MG/PU films first increased and then decreased, and the elongation at break of the composite films showed a decreasing trend. The electrical conductivity of the composite films can be influenced by filler modification and concentration, and the percolation threshold of MG/PU was 28.03 wt %. Under liner uniaxial compression, the 30 wt % MG/PU composite films exhibited 0.274 kPa−1 piezoresistive sensitivity within the range of low pressure, and possessed better stability and hysteresis. The flexible MG/PU composite piezoresistive sensors have great potential for body motion, wearable devices for human healthcare, and garment pressure testing. PMID:28773047

  15. A Novel Method for Fabricating Wearable, Piezoresistive, and Pressure Sensors Based on Modified-Graphite/Polyurethane Composite Films

    Directory of Open Access Journals (Sweden)

    Yin He

    2017-06-01

    Full Text Available A wearable, low-cost, highly repeatable piezoresistive sensor was fabricated by the synthesis of modified-graphite and polyurethane (PU composites and polydimethylsiloxane (PDMS. Graphite sheets functionalized by using a silane coupling agent (KH550 were distributed in PU/N,N-dimethylformamide (DMF solution, which were then molded to modified-graphite/PU (MG/PU composite films. Experimental results show that with increasing modified-graphite content, the tensile strength of the MG/PU films first increased and then decreased, and the elongation at break of the composite films showed a decreasing trend. The electrical conductivity of the composite films can be influenced by filler modification and concentration, and the percolation threshold of MG/PU was 28.03 wt %. Under liner uniaxial compression, the 30 wt % MG/PU composite films exhibited 0.274 kPa−1 piezoresistive sensitivity within the range of low pressure, and possessed better stability and hysteresis. The flexible MG/PU composite piezoresistive sensors have great potential for body motion, wearable devices for human healthcare, and garment pressure testing.

  16. Composite Overwrap Fragmentation Observations, Concerns, and Recommendations

    Science.gov (United States)

    Bangham, Mike; Hovater, Mary

    2017-01-01

    A series of test activities has raised some concerns about the generation of orbital debris caused by failures of composite overwrapped pressure vessels (COPVs). These tests have indicated that a large number of composite fragments can be produced by either pressure burst failures or by high-speed impacts. A review of prior high-speed tests with COPV indicates that other tests have produced large numbers of composite fragments. As was the case with the test referenced here, the tests tended to produce a large number of small composite fragments with relatively low velocities induced by the impact and or gas expansion.

  17. Measuring bacterial activity and community composition at high hydrostatic pressure using a novel experimental approach: a pilot study.

    Science.gov (United States)

    Wannicke, Nicola; Frindte, Katharina; Gust, Giselher; Liskow, Iris; Wacker, Alexander; Meyer, Andreas; Grossart, Hans-Peter

    2015-05-01

    In this pilot study, we describe a high-pressure incubation system allowing multiple subsampling of a pressurized culture without decompression. The system was tested using one piezophilic (Photobacterium profundum), one piezotolerant (Colwellia maris) bacterial strain and a decompressed sample from the Mediterranean deep sea (3044 m) determining bacterial community composition, protein production (BPP) and cell multiplication rates (BCM) up to 27 MPa. The results showed elevation of BPP at high pressure was by a factor of 1.5 ± 1.4 and 3.9 ± 2.3 for P. profundum and C. maris, respectively, compared to ambient-pressure treatments and by a factor of 6.9 ± 3.8 fold in the field samples. In P. profundum and C. maris, BCM at high pressure was elevated (3.1 ± 1.5 and 2.9 ± 1.7 fold, respectively) compared to the ambient-pressure treatments. After 3 days of incubation at 27 MPa, the natural bacterial deep-sea community was dominated by one phylum of the genus Exiguobacterium, indicating the rapid selection of piezotolerant bacteria. In future studies, our novel incubation system could be part of an isopiestic pressure chain, allowing more accurate measurement of bacterial activity rates which is important both for modeling and for predicting the efficiency of the oceanic carbon pump. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... those used to diagnose high blood pressure, prehypertension can progress to high blood pressure and should be ... pressure weakens and damages your blood vessels, which can lead to complications . Types of High Blood Pressure ...

  19. Influence of high sintering pressure on the microhardness and wear resistance of diamond powder and silicon carbide-based composites

    Directory of Open Access Journals (Sweden)

    Osipov Oleksandr Sergueevitch

    2004-01-01

    Full Text Available The work reported on here involved the development of several samples of "diamond-SiC" composite produced under sintering pressures of up to 9.0 GPa at temperatures of up to 1973 7K. The average size of the diamond micropowder crystals used was 40/28 µm. The sintering process was carried out in a 2500-ton hydraulic press equipped with an anvil-type high-pressure device having a toroidal work surface and a central concavity diameter of 20 mm. The microhardness and wear resistance of the samples were found to be dependent on the sintering pressure. The experimental results indicated that the maximum microhardness and minimum wear resistance coefficients of each compact were attained when the pressure applied during sintering exceeded 6.5 GPa. Based on the established values of pressure, this study served to identify the types of devices applicable for the manufacture of composite material inserts for a variety of rock drilling applications.

  20. The effect of swimming on pulmonary functions, blood pressure and body composition

    Directory of Open Access Journals (Sweden)

    Hasan Aykut Aysan

    2011-03-01

    Full Text Available The aim of this study was to investigate theeffect of 8 week swimming exercise on adult sedentarymen’s respiratory functions, resting heart rate, bloodpressures and body composition.Materials and methods: A total of 80 volunteers (40 inthe study group, 40 in the control group, aged between20 and 29 years were included. The participants’ bodyweight, percentage of body fat (PBF, body mass index(BMI, resting heart rate (RHR, systolic (SBP and diastolicblood pressures (DBP, and respiratory functionswere measured before and after 8 week of swimmingtraining program and compared with each other.Results: Significant decreases were observed betweenpre- and post-exercise (following 8 weeks exercise trainingin PBF (18.1±5% vs. 14.3±4%, respectively, RHR(83.1±6/min vs. 74.6±3.8/min, DBP (83±7,2 mmHg vs.74.6±3,8 mmHg (p0.001.No significant differences were found between pre-testand post-test measurements in body weight (78.1±11.4kg vs. 75.3±9.9 kg, respectively, BMI (25.2±3.9 kg/m2 vs.24.3±2.8 kg/m2 and SBP (127.6±11.8 mmHg vs.115.8±5.1 mmHg (p>0.05.Conclusion: Eight weeks swimming exercise reduced thePBF and increased the forced expiration volume, maximumvoluntarily ventilation, vital capacity and forced vitalcapacity. Swimming training also decreased RHR andbalanced DBP. J Clin Exp Invest 2011; 2(1: 35-41