The reliability of the repair weld joints of aged high temperature components in fossil power boilers

Energy Technology Data Exchange (ETDEWEB)

Okamura, Hiroyuki [Science Univ. of Tokyo (Japan); Ohtani, Ryuichi [Kyoto Univ. (Japan); Fujii, Kazuya [Japan Power Engineering and Inspection Corp., Tokyo (Japan); Yokoyama, Tomomitsu; Nishimura, Nobuhiko [Mitsubishi Heavy Industries Ltd., Tokyo (Japan); Suzuki, Komei [Japan Steel Works Ltd., Tokyo (Japan)

1998-11-01

It is of fundamental engineering importance to be able to give reliable assessments of the effective service life of the critical components used within fossil power plants, particularly for those operating for prolonged periods. It is common practice for such assessments to have been estimated using destructive tests, typically the stress rupture test, this having been recognized as one of the most reliable evaluation methods available. Its only drawback is that it often does not permit the component to be in use following the sampling of the test specimen without repairing. The current piece of work focuses on the reliability of the repair welds of components for specimens taken from fossil power plants, having been in service for prolonged periods. Several such repairs to welds have been made to an old power boiler, in particular to a superheater header which is fabricated from 2.25Cr-1Mo steel. Under close examination the repairs to the girth weldment showed susceptibilities of weld cracking, similar to that observed in as-manufactured material. Within the repaired region of the welded joint the microstructure, tensile properties and toughness seemed to be unaffected. The hardness attained its minimum value within the heat affected zone, HAZ of the repair weld, overlapping that of original girth weld HAZ. Furthermore, the stress rupture strength achieved its minimum value at the same position taking on the same value as the strength associated with the aged girth welded joint. (orig.)

A systematic concept of assuring structural integrity of components and parts for applying to highly ductile materials through brittle material

International Nuclear Information System (INIS)

Suzuki, Kazuhiko

2007-09-01

Concepts of assuring structural integrity of plant components have been developed under limited conditions of either highly ductile or brittle materials. There are some cases where operation in more and more severe conditions causes a significant reduction in ductility for materials with a high ductility before service. Use of high strength steels with relatively reduced ductility is increasing as industry applications. Current concepts of structural integrity assurance under the limited conditions of material properties or on the requirement of no significant changes in material properties even after long service will fail to incorporate expected technological innovations. A systematic concept of assuring the structural integrity should be developed for applying to highly ductile materials through brittle materials. Objectives of the on-going research are to propose a detail of the systematic concept by considering how we can develop the concept without restricting materials and for systematic considerations on a broad range of material properties from highly ductile materials through brittle materials. First, background of concepts of existing structural codes for components of highly ductile materials or for structural parts of brittle materials are discussed. Next, issues of existing code for parts of brittle materials are identified, and then resolutions to the issues are proposed. Based on the above-mentioned discussions and proposals, a systematic concept is proposed for application to components with reduced ductility materials and for applying to components of materials with significantly changing material properties due to long service. (author)

High power RF transmission line component development

International Nuclear Information System (INIS)

Hong, B. G.; Hwang, C. K.; Bae, Y. D.; Yoon, J. S.; Wang, S. J.; Gu, S. H.; Yang, J. R.; Hahm, Y. S.; Oh, G. S.; Lee, J. R.; Lee, W. I.; Park, S. H.; Kang, M. S.; Oh, S. H.; Lee, W.I.

1999-12-01

We developed the liquid stub and phase shifter which are the key high RF power transmission line components. They show reliable operation characteristics and increased insulation capability, and reduced the size by using liquid (silicon oil, dielectric constant ε=2.72) instead of gas for insulating dielectric material. They do not have finger stock for the electric contact so the local temperature rise due to irregular contact and RF breakdown due to scratch in conductor are prevented. They can be utilized in broadcasting, radar facility which require high RF power transmission. Moreover, they are key components in RF heating system for fusion reactor. (author)

High power RF transmission line component development

Energy Technology Data Exchange (ETDEWEB)

Hong, B. G.; Hwang, C. K.; Bae, Y. D.; Yoon, J. S.; Wang, S. J.; Gu, S. H.; Yang, J. R.; Hahm, Y. S.; Oh, G. S.; Lee, J. R.; Lee, W. I.; Park, S. H.; Kang, M. S.; Oh, S. H.; Lee, W.I

1999-12-01

We developed the liquid stub and phase shifter which are the key high RF power transmission line components. They show reliable operation characteristics and increased insulation capability, and reduced the size by using liquid (silicon oil, dielectric constant {epsilon}=2.72) instead of gas for insulating dielectric material. They do not have finger stock for the electric contact so the local temperature rise due to irregular contact and RF breakdown due to scratch in conductor are prevented. They can be utilized in broadcasting, radar facility which require high RF power transmission. Moreover, they are key components in RF heating system for fusion reactor. (author)

The effect of introducing increased-reliability-risk electronic components into 3rd generation telecommunications systems

International Nuclear Information System (INIS)

Salmela, Olli

2005-01-01

In this paper, the dependability of 3rd generation telecommunications network systems is studied. Special attention is paid to a case where increased-reliability-risk electronic components are introduced to the system. The paper consists of three parts: First, the reliability data of four electronic components is considered. This includes statistical analysis of the reliability test data, thermo-mechanical finite element analysis of the printed wiring board structures, and based on those, a field reliability estimate of the components is constructed. Second, the component level reliability data is introduced into the network element reliability analysis. This is accomplished by using a reliability block diagram technique and Monte Carlo simulation of the network element. The end result of the second part is a reliability estimate of the network element with and without the high-risk component. Third, the whole 3rd generation network having multiple network elements is analyzed. In this part, the criticality of introducing high-risk electronic components into a 3rd generation telecommunications network is considered

The effect of introducing increased-reliability-risk electronic components into 3rd generation telecommunications systems

Energy Technology Data Exchange (ETDEWEB)

Salmela, Olli [Nokia Networks, P.O. Box 301, 00045 Nokia Group (Finland)]. E-mail: olli.salmela@nokia.com

2005-08-01

In this paper, the dependability of 3rd generation telecommunications network systems is studied. Special attention is paid to a case where increased-reliability-risk electronic components are introduced to the system. The paper consists of three parts: First, the reliability data of four electronic components is considered. This includes statistical analysis of the reliability test data, thermo-mechanical finite element analysis of the printed wiring board structures, and based on those, a field reliability estimate of the components is constructed. Second, the component level reliability data is introduced into the network element reliability analysis. This is accomplished by using a reliability block diagram technique and Monte Carlo simulation of the network element. The end result of the second part is a reliability estimate of the network element with and without the high-risk component. Third, the whole 3rd generation network having multiple network elements is analyzed. In this part, the criticality of introducing high-risk electronic components into a 3rd generation telecommunications network is considered.

High reliability solid refractive index matching materials for field installable connections in FTTH network

Science.gov (United States)

Saito, Kotaro; Kihara, Mitsuru; Shimizu, Tomoya; Yoneda, Keisuke; Kurashima, Toshio

2015-06-01

We performed environmental and accelerated aging tests to ensure the long-term reliability of solid type refractive index matching material at a splice point. Stable optical characteristics were confirmed in environmental tests based on an IEC standard. In an accelerated aging test at 140 °C, which is very much higher than the specification test temperature, the index matching material itself and spliced fibers passing through it had steady optical characteristics. Then we performed an accelerated aging test on an index matching material attached to a built-in fiber before splicing it in the worst condition, which is different from the normal use configuration. As a result, we confirmed that the repeated insertion and removal of fiber for splicing resulted in failure. We consider that the repetition of adhesion between index matching material and fibers causes the splice to degrade. With this result, we used the Arrhenius model to estimate a median lifetime of about 68 years in a high temperature environment of 60 °C. Thus solid type index matching material at a splice point is highly reliable over long periods under normal conditions of use.

Research of application of new material to light water reactor components

International Nuclear Information System (INIS)

Mihara, Tanetoyo

1992-01-01

Advanced Nuclear Equipment Research Institute (ANERI) has been doing the research to apply the new material including metal, fine ceramics and high polymer which were developed and applied in other industries to components and parts of light water reactor for the purpose of Improvement of reliability of components, improvement of efficiency of periodic inspection, improvement of repair and reduction of radiation exposure of worker. This project started upon the sponsorship of Ministry of International Trade and Industry (MITI) by the schedule of FY1985-FY1993 (9 years) and effective results has been obtained. (author)

Analysis on Sealing Reliability of Bolted Joint Ball Head Component of Satellite Propulsion System

Science.gov (United States)

Guo, Tao; Fan, Yougao; Gao, Feng; Gu, Shixin; Wang, Wei

2018-01-01

Propulsion system is one of the important subsystems of satellite, and its performance directly affects the service life, attitude control and reliability of the satellite. The Paper analyzes the sealing principle of bolted joint ball head component of satellite propulsion system and discuss from the compatibility of hydrazine anhydrous and bolted joint ball head component, influence of ground environment on the sealing performance of bolted joint ball heads, and material failure caused by environment, showing that the sealing reliability of bolted joint ball head component is good and the influence of above three aspects on sealing of bolted joint ball head component can be ignored.

Reliability analysis of component of affination centrifugal 1 machine by using reliability engineering

Science.gov (United States)

Sembiring, N.; Ginting, E.; Darnello, T.

2017-12-01

Problems that appear in a company that produces refined sugar, the production floor has not reached the level of critical machine availability because it often suffered damage (breakdown). This results in a sudden loss of production time and production opportunities. This problem can be solved by Reliability Engineering method where the statistical approach to historical damage data is performed to see the pattern of the distribution. The method can provide a value of reliability, rate of damage, and availability level, of an machine during the maintenance time interval schedule. The result of distribution test to time inter-damage data (MTTF) flexible hose component is lognormal distribution while component of teflon cone lifthing is weibull distribution. While from distribution test to mean time of improvement (MTTR) flexible hose component is exponential distribution while component of teflon cone lifthing is weibull distribution. The actual results of the flexible hose component on the replacement schedule per 720 hours obtained reliability of 0.2451 and availability 0.9960. While on the critical components of teflon cone lifthing actual on the replacement schedule per 1944 hours obtained reliability of 0.4083 and availability 0.9927.

Reliability-based sensitivity of mechanical components with arbitrary distribution parameters

International Nuclear Information System (INIS)

Zhang, Yi Min; Yang, Zhou; Wen, Bang Chun; He, Xiang Dong; Liu, Qiaoling

2010-01-01

This paper presents a reliability-based sensitivity method for mechanical components with arbitrary distribution parameters. Techniques from the perturbation method, the Edgeworth series, the reliability-based design theory, and the sensitivity analysis approach were employed directly to calculate the reliability-based sensitivity of mechanical components on the condition that the first four moments of the original random variables are known. The reliability-based sensitivity information of the mechanical components can be accurately and quickly obtained using a practical computer program. The effects of the design parameters on the reliability of mechanical components were studied. The method presented in this paper provides the theoretic basis for the reliability-based design of mechanical components

Parts and Components Reliability Assessment: A Cost Effective Approach

Science.gov (United States)

Lee, Lydia

2009-01-01

System reliability assessment is a methodology which incorporates reliability analyses performed at parts and components level such as Reliability Prediction, Failure Modes and Effects Analysis (FMEA) and Fault Tree Analysis (FTA) to assess risks, perform design tradeoffs, and therefore, to ensure effective productivity and/or mission success. The system reliability is used to optimize the product design to accommodate today?s mandated budget, manpower, and schedule constraints. Stand ard based reliability assessment is an effective approach consisting of reliability predictions together with other reliability analyses for electronic, electrical, and electro-mechanical (EEE) complex parts and components of large systems based on failure rate estimates published by the United States (U.S.) military or commercial standards and handbooks. Many of these standards are globally accepted and recognized. The reliability assessment is especially useful during the initial stages when the system design is still in the development and hard failure data is not yet available or manufacturers are not contractually obliged by their customers to publish the reliability estimates/predictions for their parts and components. This paper presents a methodology to assess system reliability using parts and components reliability estimates to ensure effective productivity and/or mission success in an efficient manner, low cost, and tight schedule.

Radiation durability and functional reliability of polymeric materials in space systems

International Nuclear Information System (INIS)

Haruvy, Y.

1990-01-01

Polymeric materials are preferred for the light-weight construction of space-systems. Materials in space systems are required to fulfill a complete set of specifications, at utmost reliability, throughout the whole period of service in space, while being exposed to the hazardous influence of the space environment. The major threats of the space environment in orbits at the geostationary altitude (GSO) arise from ionizing radiations, the main constituents of which are highly energetic protons (affecting mainly the surface) and fast electrons (which produce the main threat to the electronic components). The maximum dose of ionizing radiation (within the limits of uncertainty of the calculations) at the surface of a material mounted on a space system, namely the ''Skin-Dose'', is ca. 2500 Mrads/yr. Space systems such as telecommunication satellites are planned to serve for prolonged periods of 30 years and longer. The cumulative predicted dose of ionizing-radiation over such periods presents a severe threat of chemical degradation to most of the polymeric construction materials commonly utilized in space systems. The reliability of each of the polymeric materials must be evaluated in detail, considering each of the relevant typical threats, such as ionizing-radiation, UV radiation, meteoroides flux, thermal cycling and ultra-high vacuum. For each of the exposed materials, conservation of the set of functional characteristics such as mechanical integrity, electrical and thermo-optical properties, electrical conductivity, surface charging and outgassing properties, which may cause contamination of neighboring systems, is evaluated. The reliability of functioning of the materials exposed to the space environment can thus be predicted, utilizing data from the literature, experimental results reported from space flights and laboratory simulations, and by chemical similarity of untested polymers to others. (author)

Assuring the reliability of structural components - experimental data and non-destructive examination requirements

International Nuclear Information System (INIS)

Lucia, A.C.

1984-01-01

The probability of failure of a structural component can be estimated by either statistical methods or a probabilistic structural reliability approach (where the failure is seen as a level crossing of a damage stochastic process which develops in space and in time). The probabilistic approach has the advantage that it makes available not only an absolute value of the failure probability but also a lot of additional information. The disadvantage of the probabilistic approach is its complexity. It is discussed for the following situations: reliability of a structural component, material properties, data for fatigue crack growth evaluation, a bench mark exercise on reactor pressure vessel failure probability computation, and non-destructive examination for assuring a given level of structural reliability. (U.K.)

Functional components for a design strategy: Hot cell shielding in the high reliability safeguards methodology

Energy Technology Data Exchange (ETDEWEB)

Borrelli, R.A., E-mail: rborrelli@uidaho.edu

2016-08-15

The high reliability safeguards (HRS) methodology has been established for the safeguardability of advanced nuclear energy systems (NESs). HRS is being developed in order to integrate safety, security, and safeguards concerns, while also optimizing these with operational goals for facilities that handle special nuclear material (SNM). Currently, a commercial pyroprocessing facility is used as an example system. One of the goals in the HRS methodology is to apply intrinsic features of the system to a design strategy. This current study investigates the thickness of the hot cell walls that could adequately shield processed materials. This is an important design consideration that carries implications regarding the formation of material balance areas, the location of key measurement points, and material flow in the facility.

A new model for reliability optimization of series-parallel systems with non-homogeneous components

International Nuclear Information System (INIS)

Feizabadi, Mohammad; Jahromi, Abdolhamid Eshraghniaye

2017-01-01

In discussions related to reliability optimization using redundancy allocation, one of the structures that has attracted the attention of many researchers, is series-parallel structure. In models previously presented for reliability optimization of series-parallel systems, there is a restricting assumption based on which all components of a subsystem must be homogeneous. This constraint limits system designers in selecting components and prevents achieving higher levels of reliability. In this paper, a new model is proposed for reliability optimization of series-parallel systems, which makes possible the use of non-homogeneous components in each subsystem. As a result of this flexibility, the process of supplying system components will be easier. To solve the proposed model, since the redundancy allocation problem (RAP) belongs to the NP-hard class of optimization problems, a genetic algorithm (GA) is developed. The computational results of the designed GA are indicative of high performance of the proposed model in increasing system reliability and decreasing costs. - Highlights: • In this paper, a new model is proposed for reliability optimization of series-parallel systems. • In the previous models, there is a restricting assumption based on which all components of a subsystem must be homogeneous. • The presented model provides a possibility for the subsystems’ components to be non- homogeneous in the required conditions. • The computational results demonstrate the high performance of the proposed model in improving reliability and reducing costs.

Recent developments in turbomachinery component materials and manufacturing challenges for aero engine applications

Science.gov (United States)

Srinivas, G.; Raghunandana, K.; Satish Shenoy, B.

2018-02-01

In the recent years the development of turbomachinery materials performance enhancement plays a vital role especially in aircraft air breathing engines like turbojet engine, turboprop engine, turboshaft engine and turbofan engines. Especially the transonic flow engines required highly sophisticated materials where it can sustain the entire thrust which can create by the engine. The main objective of this paper is to give an overview of the present cost-effective and technological capabilities process for turbomachinery component materials. Especially the main focus is given to study the Electro physical, Photonic additive removal process and Electro chemical process for turbomachinery parts manufacture. The aeronautical propulsion based technologies are reviewed thoroughly where in surface reliability, geometrical precession, and material removal and highly strengthened composite material deposition rates usually difficult to cut dedicated steels, Titanium and Nickel based alloys. In this paper the past aeronautical and propulsion mechanical based manufacturing technologies, current sophisticated technologies and also future challenging material processing techniques are covered. The paper also focuses on the brief description of turbomachinery components of shaping process and coating in aeromechanical applications.

Application of fuzzy-MOORA method: Ranking of components for reliability estimation of component-based software systems

Directory of Open Access Journals (Sweden)

Zeeshan Ali Siddiqui

2016-01-01

Full Text Available Component-based software system (CBSS development technique is an emerging discipline that promises to take software development into a new era. As hardware systems are presently being constructed from kits of parts, software systems may also be assembled from components. It is more reliable to reuse software than to create. It is the glue code and individual components reliability that contribute to the reliability of the overall system. Every component contributes to overall system reliability according to the number of times it is being used, some components are of critical usage, known as usage frequency of component. The usage frequency decides the weight of each component. According to their weights, each component contributes to the overall reliability of the system. Therefore, ranking of components may be obtained by analyzing their reliability impacts on overall application. In this paper, we propose the application of fuzzy multi-objective optimization on the basis of ratio analysis, Fuzzy-MOORA. The method helps us find the best suitable alternative, software component, from a set of available feasible alternatives named software components. It is an accurate and easy to understand tool for solving multi-criteria decision making problems that have imprecise and vague evaluation data. By the use of ratio analysis, the proposed method determines the most suitable alternative among all possible alternatives, and dimensionless measurement will realize the job of ranking of components for estimating CBSS reliability in a non-subjective way. Finally, three case studies are shown to illustrate the use of the proposed technique.

Reliability estimation for check valves and other components

International Nuclear Information System (INIS)

McElhaney, K.L.; Staunton, R.H.

1996-01-01

For years the nuclear industry has depended upon component operational reliability information compiled from reliability handbooks and other generic sources as well as private databases generated by recognized experts both within and outside the nuclear industry. Regrettably, these technical bases lacked the benefit of large-scale operational data and comprehensive data verification, and did not take into account the parameters and combinations of parameters that affect the determination of failure rates. This paper briefly examines the historic use of generic component reliability data, its sources, and its limitations. The concept of using a single failure rate for a particular component type is also examined. Particular emphasis is placed on check valves due to the information available on those components. The Appendix presents some of the results of the extensive analyses done by Oak Ridge National Laboratory (ORNL) on check valve performance

Imprecise system reliability and component importance based on survival signature

International Nuclear Information System (INIS)

Feng, Geng; Patelli, Edoardo; Beer, Michael; Coolen, Frank P.A.

2016-01-01

The concept of the survival signature has recently attracted increasing attention for performing reliability analysis on systems with multiple types of components. It opens a new pathway for a structured approach with high computational efficiency based on a complete probabilistic description of the system. In practical applications, however, some of the parameters of the system might not be defined completely due to limited data, which implies the need to take imprecisions of component specifications into account. This paper presents a methodology to include explicitly the imprecision, which leads to upper and lower bounds of the survival function of the system. In addition, the approach introduces novel and efficient component importance measures. By implementing relative importance index of each component without or with imprecision, the most critical component in the system can be identified depending on the service time of the system. Simulation method based on survival signature is introduced to deal with imprecision within components, which is precise and efficient. Numerical example is presented to show the applicability of the approach for systems. - Highlights: • Survival signature is a novel way for system reliability and component importance • High computational efficiency based on a complete description of system. • Include explicitly the imprecision, which leads to bounds of the survival function. • A novel relative importance index is proposed as importance measure. • Allows to identify critical components depending on the service time of the system.

Advanced materials for critical components in industrial gas turbines

Energy Technology Data Exchange (ETDEWEB)

Gibbons, T.B. (Div. of Materials Metrology, National Physical Lab., Teddington (United Kingdom))

1992-06-01

Combined-cycle plant for power production has advantages in terms of capital costs and flexibility compared to large power plants either nuclear of fossil-fired, used for base load. In combined-cycle plant the overall efficiency is highly dependent on the performance of the gas turbine and turbine entry temperatures of > 1200deg C will be required to obtain attractive levels of efficiency. Bearing in mind the need for reliability and longterm performance from components such as turbine blades, the challenge to the materials enginer is formidable. In this paper some of the recent developments in Ni - Cr-base alloys are described and the potential for advanced materials such as ceramics and intermetallics is briefly considered. Development in coating technology to provide effective thermal barriers and good resistance to aggressive environments are discussed. (orig./MM).

Materials and Reliability Handbook for Semiconductor Optical and Electron Devices

CERN Document Server

Pearton, Stephen

2013-01-01

Materials and Reliability Handbook for Semiconductor Optical and Electron Devices provides comprehensive coverage of reliability procedures and approaches for electron and photonic devices. These include lasers and high speed electronics used in cell phones, satellites, data transmission systems and displays. Lifetime predictions for compound semiconductor devices are notoriously inaccurate due to the absence of standard protocols. Manufacturers have relied on extrapolation back to room temperature of accelerated testing at elevated temperature. This technique fails for scaled, high current density devices. Device failure is driven by electric field or current mechanisms or low activation energy processes that are masked by other mechanisms at high temperature. The Handbook addresses reliability engineering for III-V devices, including materials and electrical characterization, reliability testing, and electronic characterization. These are used to develop new simulation technologies for device operation and ...

Reliability Evaluation of Machine Center Components Based on Cascading Failure Analysis

Science.gov (United States)

Zhang, Ying-Zhi; Liu, Jin-Tong; Shen, Gui-Xiang; Long, Zhe; Sun, Shu-Guang

2017-07-01

In order to rectify the problems that the component reliability model exhibits deviation, and the evaluation result is low due to the overlook of failure propagation in traditional reliability evaluation of machine center components, a new reliability evaluation method based on cascading failure analysis and the failure influenced degree assessment is proposed. A direct graph model of cascading failure among components is established according to cascading failure mechanism analysis and graph theory. The failure influenced degrees of the system components are assessed by the adjacency matrix and its transposition, combined with the Pagerank algorithm. Based on the comprehensive failure probability function and total probability formula, the inherent failure probability function is determined to realize the reliability evaluation of the system components. Finally, the method is applied to a machine center, it shows the following: 1) The reliability evaluation values of the proposed method are at least 2.5% higher than those of the traditional method; 2) The difference between the comprehensive and inherent reliability of the system component presents a positive correlation with the failure influenced degree of the system component, which provides a theoretical basis for reliability allocation of machine center system.

Assessment of microelectronics packaging for high temperature, high reliability applications

Energy Technology Data Exchange (ETDEWEB)

Uribe, F.

1997-04-01

This report details characterization and development activities in electronic packaging for high temperature applications. This project was conducted through a Department of Energy sponsored Cooperative Research and Development Agreement between Sandia National Laboratories and General Motors. Even though the target application of this collaborative effort is an automotive electronic throttle control system which would be located in the engine compartment, results of this work are directly applicable to Sandia`s national security mission. The component count associated with the throttle control dictates the use of high density packaging not offered by conventional surface mount. An enabling packaging technology was selected and thermal models defined which characterized the thermal and mechanical response of the throttle control module. These models were used to optimize thick film multichip module design, characterize the thermal signatures of the electronic components inside the module, and to determine the temperature field and resulting thermal stresses under conditions that may be encountered during the operational life of the throttle control module. Because the need to use unpackaged devices limits the level of testing that can be performed either at the wafer level or as individual dice, an approach to assure a high level of reliability of the unpackaged components was formulated. Component assembly and interconnect technologies were also evaluated and characterized for high temperature applications. Electrical, mechanical and chemical characterizations of enabling die and component attach technologies were performed. Additionally, studies were conducted to assess the performance and reliability of gold and aluminum wire bonding to thick film conductor inks. Kinetic models were developed and validated to estimate wire bond reliability.

Design and implementation of component reliability database management system for NPP

International Nuclear Information System (INIS)

Kim, S. H.; Jung, J. K.; Choi, S. Y.; Lee, Y. H.; Han, S. H.

1999-01-01

KAERI is constructing the component reliability database for Korean nuclear power plant. This paper describes the development of data management tool, which runs for component reliability database. This is running under intranet environment and is used to analyze the failure mode and failure severity to compute the component failure rate. Now we are developing the additional modules to manage operation history, test history and algorithms for calculation of component failure history and reliability

Column Grid Array Rework for High Reliability

Science.gov (United States)

Mehta, Atul C.; Bodie, Charles C.

2008-01-01

Due to requirements for reduced size and weight, use of grid array packages in space applications has become common place. To meet the requirement of high reliability and high number of I/Os, ceramic column grid array packages (CCGA) were selected for major electronic components used in next MARS Rover mission (specifically high density Field Programmable Gate Arrays). ABSTRACT The probability of removal and replacement of these devices on the actual flight printed wiring board assemblies is deemed to be very high because of last minute discoveries in final test which will dictate changes in the firmware. The questions and challenges presented to the manufacturing organizations engaged in the production of high reliability electronic assemblies are, Is the reliability of the PWBA adversely affected by rework (removal and replacement) of the CGA package? and How many times can we rework the same board without destroying a pad or degrading the lifetime of the assembly? To answer these questions, the most complex printed wiring board assembly used by the project was chosen to be used as the test vehicle, the PWB was modified to provide a daisy chain pattern, and a number of bare PWB s were acquired to this modified design. Non-functional 624 pin CGA packages with internal daisy chained matching the pattern on the PWB were procured. The combination of the modified PWB and the daisy chained packages enables continuity measurements of every soldered contact during subsequent testing and thermal cycling. Several test vehicles boards were assembled, reworked and then thermal cycled to assess the reliability of the solder joints and board material including pads and traces near the CGA. The details of rework process and results of thermal cycling are presented in this paper.

Plasma facing materials and components for future fusion devices - development, characterization and performance under fusion specific loading conditions

Energy Technology Data Exchange (ETDEWEB)

Linke, J. [Forschungszentrum Juelich (Germany). Inst. fuer Plasmaphysik

2006-04-15

The plasma exposed components in existing and future fusion devices are strongly affected by the plasma material interaction processes. These mechanisms have a strong influence on the plasma performance; in addition they have major impact on the lifetime of the plasma facing armour and the joining interface between the plasma facing material (PFM) and the heat sink. Besides physical and chemical sputtering processes, high heat quasi-stationary fluxes during normal and intense thermal transients are of serious concern for the engineers who develop reliable wall components. In addition, the material and component degradation due to intense fluxes of energetic neutrons is another critical issue in D-T-burning fusion devices which requires extensive RandD. This paper presents an overview on the materials development and joining, the testing of PFMs and components, and the analysis of the neutron irradiation induced degradation.

Plasma facing materials and components for future fusion devices - development, characterization and performance under fusion specific loading conditions

International Nuclear Information System (INIS)

Linke, J.

2006-01-01

The plasma exposed components in existing and future fusion devices are strongly affected by the plasma material interaction processes. These mechanisms have a strong influence on the plasma performance; in addition they have major impact on the lifetime of the plasma facing armour and the joining interface between the plasma facing material (PFM) and the heat sink. Besides physical and chemical sputtering processes, high heat quasi-stationary fluxes during normal and intense thermal transients are of serious concern for the engineers who develop reliable wall components. In addition, the material and component degradation due to intense fluxes of energetic neutrons is another critical issue in D-T-burning fusion devices which requires extensive RandD. This paper presents an overview on the materials development and joining, the testing of PFMs and components, and the analysis of the neutron irradiation induced degradation

Plasma facing materials and components for future fusion devices—development, characterization and performance under fusion specific loading conditions

Science.gov (United States)

Linke, J.

2006-04-01

The plasma exposed components in existing and future fusion devices are strongly affected by the plasma material interaction processes. These mechanisms have a strong influence on the plasma performance; in addition they have major impact on the lifetime of the plasma facing armour and the joining interface between the plasma facing material (PFM) and the heat sink. Besides physical and chemical sputtering processes, high heat quasi-stationary fluxes during normal and intense thermal transients are of serious concern for the engineers who develop reliable wall components. In addition, the material and component degradation due to intense fluxes of energetic neutrons is another critical issue in D-T-burning fusion devices which requires extensive R&D. This paper presents an overview on the materials development and joining, the testing of PFMs and components, and the analysis of the neutron irradiation induced degradation.

Optimization of Reliability Centered Maintenance Bassed on Maintenance Costs and Reliability with Consideration of Location of Components

Directory of Open Access Journals (Sweden)

Mahdi Karbasian

2011-03-01

Full Text Available The reliability of designing systems such as electrical and electronic circuits, power generation/ distribution networks and mechanical systems, in which the failure of a component may cause the whole system failure, and even the reliability of cellular manufacturing systems that their machines are connected to as series are critically important. So far approaches for improving the reliability of these systems have been mainly based on the enhancement of inherent reliability of any system component or increasing system reliability based on maintenance strategies. Also in some of the resources, only the influence of the location of systems' components on reliability is studied. Therefore, it seems other approaches have been rarely applied. In this paper, a multi criteria model has been proposed to perform a balance among a system's reliability, location costs, and its system maintenance. Finally, a numerical example has been presented and solved by the Lingo software.

Radiation and temperature effects on electronic components investigated under the CSTI high capacity power project

International Nuclear Information System (INIS)

Schwarze, G.E.; Niedra, J.M.; Frasca, A.J.; Wieserman, W.R.

1993-01-01

The effects of nuclear radiation and high temperature environments must be fully known and understood for the electronic components and materials used in both the Power Conditioning and Control subsystem and the reactor Instrumentation and Control subsystem of future high capacity nuclear space power systems. This knowledge is required by the designer of these subsystems in order to develop highly reliable, long-life power systems for future NASA missions. A review and summary of the experimental results obtained for the electronic components and materials investigated under the power management element of the CSTI high capacity power project will be presented in this paper: (1) Neutron, gamma ray, and temperature effects on power semiconductor switches, (2) Temperature and frequency effects on soft magnetic materials; and (3) Temperature effects on rare-earth permanent magnets

Radiation and temperature effects on electronic components investigated under the CSTI High Capacity Power Project

International Nuclear Information System (INIS)

Shwarze, G.E.; Wieserman, W.R.

1994-01-01

The effects of nuclear radiation and high temperature environments must be fully known and understood for the electronic components and materials used in both the Power Conditioning and Control subsystem and the reactor Instrumentation and Control subsystem of future high capacity nuclear space power systems. This knowledge is required by the designer of these subsystems in order to develop highly reliable, long-life power systems for future NASA missions. A review and summary of the experimental results obtained for the electronic components and materials investigated under the power management element of the CSTI high capacity power project will be presented in this paper: (1) Neutron, gamma ray, and temperature effects on power semiconductor switches, (2) Temperature and frequency effects on soft magnetic materials; and (3) Temperature effects on rare earth permanent magnets

Structural Reliability Methods for Wind Power Converter System Component Reliability Assessment

DEFF Research Database (Denmark)

Kostandyan, Erik; Sørensen, John Dalsgaard

2012-01-01

Wind power converter systems are essential subsystems in both off-shore and on-shore wind turbines. It is the main interface between generator and grid connection. This system is affected by numerous stresses where the main contributors might be defined as vibration and temperature loadings....... The temperature variations induce time-varying stresses and thereby fatigue loads. A probabilistic model is used to model fatigue failure for an electrical component in the power converter system. This model is based on a linear damage accumulation and physics of failure approaches, where a failure criterion...... is defined by the threshold model. The attention is focused on crack propagation in solder joints of electrical components due to the temperature loadings. Structural Reliability approaches are used to incorporate model, physical and statistical uncertainties. Reliability estimation by means of structural...

Origin and type of flaws in heat engine ceramic materials and components

International Nuclear Information System (INIS)

Govila, R.K.

1995-01-01

A number of ceramic materials such as Silicon Nitrides and Carbides, Sialons, Whisker-Reinforced Ceramic Composites and Partially-Stabilized Zirconias (PSZs) have been developed for use as structural components in heat engine applications. The reliability and durability of a structural engine component is critically dependent on the size, density of distribution and location of flaws. This information is critical for the processing and design engineers in order to design structural components using suitable materials and thus minimize stress intensity. In general, the failure initiating flaws are associated or produced due to material impurity, processing methods and parameters, and fabrication techniques (machining and grinding). Examples of each type of flaws associated with material impurity, processing methods and fabrication techniques are illustrated

Reliability for systems of degrading components with distinct component shock sets

International Nuclear Information System (INIS)

Song, Sanling; Coit, David W.; Feng, Qianmei

2014-01-01

This paper studies reliability for multi-component systems subject to dependent competing risks of degradation wear and random shocks, with distinct shock sets. In practice, many systems are exposed to distinct and different types of shocks that can be categorized according to their sizes, function, affected components, etc. Previous research primarily focuses on simple systems with independent failure processes, systems with independent component time-to-failure, or components that share the same shock set or type of shocks. In our new model, we classify random shocks into different sets based on their sizes or function. Shocks with specific sizes or function can selectively affect one or more components in the system but not necessarily all components. Additionally the shocks from the different shock sets can arrive at different rates and have different relative magnitudes. Preventive maintenance (PM) optimization is conducted for the system with different component shock sets. Decision variables for two different maintenance scheduling problems, the PM replacement time interval, and the PM inspection time interval, are determined by minimizing a defined system cost rate. Sensitivity analysis is performed to provide insight into the behavior of the proposed maintenance policies. These models can be applied directly or customized for many complex systems that experience dependent competing failure processes with different component shock sets. A MEMS (Micro-electro mechanical systems) oscillator is a typical system subject to dependent and competing failure processes, and it is used as a numerical example to illustrate our new reliability and maintenance models

IAEA's experience in compiling a generic component reliability data base

International Nuclear Information System (INIS)

Tomic, B.; Lederman, L.

1991-01-01

Reliability data are essential in probabilistic safety assessment, with component reliability parameters being particularly important. Component failure data which is plant specific would be most appropriate but this is rather limited. However, similar components are used in different designs. Generic data, that is all data that is not plant specific to the plant being analyzed but which relates to components more generally, is important. The International Atomic Energy Agency has compiled the Generic Component Reliability Data Base from data available in the open literature. It is part of the IAEA computer code package for fault/event tree analysis. The Data Base contains 1010 different records including most of the components used in probabilistic safety analyses of nuclear power plants. The data base input was quality controlled and data sources noted. The data compilation procedure and problems associated with using generic data are explained. (UK)

Material Selection for Cable Gland to Improved Reliability of the High-hazard Industries

Science.gov (United States)

Vashchuk, S. P.; Slobodyan, S. M.; Deeva, V. S.; Vashchuk, D. S.

2018-01-01

The sealed cable glands (SCG) are available to ensure safest connection sheathed single wire for the hazard production facility (nuclear power plant and others) the same as pilot cable, control cables, radio-frequency cables et al. In this paper, we investigate the specifics of the material selection of SCG with the express aim of hazardous man-made facility. We discuss the safe working conditions for cable glands. The research indicates the sintering powdered metals cables provide the reliability growth due to their properties. A number of studies have demonstrated the verification of material selection. On the face of it, we make findings indicating that double glazed sealed units could enhance reliability. We had evaluated sample reliability under fire conditions, seismic load, and pressure containment failure. We used the samples mineral insulated thermocouple cable.

Dynamic k-out-of-n system reliability with component partnership

International Nuclear Information System (INIS)

Coit, David W.; Chatwattanasiri, Nida; Wattanapongsakorn, Naruemon; Konak, Abdullah

2015-01-01

This paper describes a new k-out-of-n system reliability model that is appropriate for certain design problems when the minimum number of required components, k, changes dynamically in response to failures to maximize the utility of the available collection of functioning components. This new model shares some distinct similarities with weighted k-out-of-n models and for some problems they produce the same result. However, there are subtle and distinct differences, and in practice, there are some complex applications have not been properly explained or modeled by traditional or extended k-out-of-n system models. For this application, components are arranged in a k-out-of-n configuration of heterogeneous components with different performance levels. Component performance is indicated by a component-specific component partnership level; the fewer partners required to operate successfully implies higher performance. The components can work collectively with partners at the same level to maintain system reliability, or they can create a partnership group with components at higher performance levels which serve as replacements to provide the necessary number of working components. When components fail, the dynamic k-out-of-n configuration maintains reliability of the system with changing k by having components create partnerships with other components at the same level or above. To demonstrate the model, a system replacement maintenance policy based on a replacement interval variable is applied to an example system to obtain the optimal replacement time. - Highlights: • A new k-out-of-n system reliability model is presented. • Components can form partnerships with other components. • The new k-out-of-n model is presented with a dynamic or changing k. • The new model is for systems with components that must work together in a group

Reliability prediction of engineering systems with competing failure modes due to component degradation

International Nuclear Information System (INIS)

Son, Young Kap

2011-01-01

Reliability of an engineering system depends on two reliability metrics: the mechanical reliability, considering component failures, that a functional system topology is maintained and the performance reliability of adequate system performance in each functional configuration. Component degradation explains not only the component aging processes leading to failure in function, but also system performance change over time. Multiple competing failure modes for systems with degrading components in terms of system functionality and system performance are considered in this paper with the assumption that system functionality is not independent of system performance. To reduce errors in system reliability prediction, this paper tries to extend system performance reliability prediction methods in open literature through combining system mechanical reliability from component reliabilities and system performance reliability. The extended reliability prediction method provides a useful way to compare designs as well as to determine effective maintenance policy for efficient reliability growth. Application of the method to an electro-mechanical system, as an illustrative example, is explained in detail, and the prediction results are discussed. Both mechanical reliability and performance reliability are compared to total system reliability in terms of reliability prediction errors

Component reliability data for use in probabilistic safety assessment

International Nuclear Information System (INIS)

1988-10-01

Generic component reliability data is indispensable in any probabilistic safety analysis. It is not realistic to assume that all possible component failures and failure modes modeled in a PSA would be available from the operating experience of a specific plant in a statistically meaningful way. The degree that generic data is used in PSAs varies from case to case. Some studies are totally based on generic data while others use generic data as prior information to be specialized by plant specific data. Most studies, however, finally use a combination where data for certain components come from generic data sources and others from Bayesian updating. The IAEA effort to compile a generic component reliability data base aimed at facilitating the use of data available in the literature and at highlighting pitfalls which deserve special consideration. It was also intended to complement the fault tree and event tree package (PSAPACK) and to facilitate its use. Moreover, it should be noted, that the IAEA has recently initiated a Coordinated Research Program in Reliability Data Collection, Retrieval and Analysis. In this framework the issues identified as most affecting the quality of existing data bases would be addressed. This report presents the results of a compilation made from the specialized literature and includes reliability data for components usually considered in PSA

Behaviour of alkali halides as materials for optical components of high power lasers

International Nuclear Information System (INIS)

Apostol, D.I.; Mihailescu, N.I.; Ghiordanescu, V.; Nistor, C.L.; Nistor, V.S.; Teodorescu, V.; Voda, M.

1978-01-01

The physical phenomena taking place in alkali halides when a CO 2 laser radiation is passing through have been reviewed. A special emphasis has been put on the specific qualities which such materials should have for being used as components for high power lasers. (author)

Mechanical properties, reliability assessment and design of ceramic components used in high temperature assemblies

International Nuclear Information System (INIS)

Bendeich, P.J.

2002-01-01

The use of ceramic materials in high temperature structural components holds may advantages over conventional materials such as metals. These include high temperature strength, creep resistance, wear resistance, corrosion resistance, and stiffness. The tradeoff for these improved properties is the brittle nature of ceramics and their tendency for catastrophic failure and lack of damage tolerance. In this work some the various strategies available to overcome these limitations are reviewed. These include stochastic design strategies using the Weibull and Batdorf methods of failure probability prediction rather than the more familiar deterministic methods. Fracture mechanics analysis is also used extensively in this work to predict damage tolerance and failure conditions. A range of testing methods was utilised to provide material information for the methods outlined above. These included: flexural strength measurement for the determination of failure probability parameters; fracture toughness measurement using indentation methods and crack growth measurement; thermal expansion measurement; temperature dependant dynamic Young's modulus measurement; and thermal shock testing using a central heating laser. A new inverse method for measuring specific heat was developed and critically examined for practical use. This is particularly valuable in modelling transient thermal conditions for use in thermal shock analysis. A shape optimisation technique utilising a biological growth law was adapted for use with ceramic components utilising failure probability as the objective function. These methods were utilised in the design and subsequent failure analysis of a high temperature hotpress ram. The results of the failure probability analysis showed that the design had a very low probability of failure under normal operating conditions. Fracture mechanics analysis indicated that damage tolerance in the critical retaining bolt mechanism was high with damage likely to cause

Reliability prediction system based on the failure rate model for electronic components

International Nuclear Information System (INIS)

Lee, Seung Woo; Lee, Hwa Ki

2008-01-01

Although many methodologies for predicting the reliability of electronic components have been developed, their reliability might be subjective according to a particular set of circumstances, and therefore it is not easy to quantify their reliability. Among the reliability prediction methods are the statistical analysis based method, the similarity analysis method based on an external failure rate database, and the method based on the physics-of-failure model. In this study, we developed a system by which the reliability of electronic components can be predicted by creating a system for the statistical analysis method of predicting reliability most easily. The failure rate models that were applied are MILHDBK- 217F N2, PRISM, and Telcordia (Bellcore), and these were compared with the general purpose system in order to validate the effectiveness of the developed system. Being able to predict the reliability of electronic components from the stage of design, the system that we have developed is expected to contribute to enhancing the reliability of electronic components

Magnetic fusion energy plasma interactive and high heat flux components. Volume III. Strategy for international collaborations in the areas of plasma materials interactions and high heat flux materials and components development

International Nuclear Information System (INIS)

Gauster, W.B.; Bauer, W.; Roberto, J.B.; Post, D.E.

1984-01-01

The purpose of this summary is to assess opportunities for such collaborations in the specific areas of Plasma Materials Interaction and High Heat Flux Materials and Components Development, and to aid in developing a strategy to take advantage of them. After some general discussion of international collaborations, we summarize key technical issues and the US programs to address them. Then follows a summary of present collaborations and potential opportunities in foreign laboratories

Generic component reliability data for research reactor PSA

International Nuclear Information System (INIS)

1997-02-01

The purpose of this document is to provide reference generic component-reliability information for a variety of research reactor types. As noted in Section 2 and Table IV, component data accumulated over many years is in the database. It is expected that the report should provide representative data which will remain valid for a number of years. The database provides component failure rates on a time and/or demand related basis according to the operational modes of the components. No update of the database is presently planned. As a result of the implementation of data collection systems in the research reactors represented in these studies, updating of data from individual facilities could be made available by the contributing research reactor facilities themselves. As noted in Section 1.1, the report does not include a detailed discussion of information regarding component classification and reliability parameter definitions. The report does provide some insights and discussions regarding the practicalities of the data collection process and some guidelines for database usage. 9 refs, 7 tabs

Material and design considerations of FBGA reliability performance

International Nuclear Information System (INIS)

Lee, Teck Kheng; Ng, T.C.; Chai, Y.M.

2004-01-01

FBGA package reliability is usually assessed through the conventional approaches of die attach and mold compound material optimization. However, with the rapid changes and fast-moving pace of electronic packaging and the introduction of new soldermask and core materials, substrate design has also become a critical factor in determining overall package reliability. The purpose of this paper is to understand the impact design and soldermask material of a rigid substrate on overall package reliability. Three different soldermask patterns with a matrix of different die attach, mold compound, and soldermask materials are assessed using the moisture sensitivity test (MST). Package reliability is also assessed through the use of temperature cycling (T/C) at conditions 'B' and 'C'. For material optimization, three different mold compounds and die attach materials are used. Material adhesion between different die attach materials and soldermask materials are obtained through die shear performed at various temperatures and preset moisture conditions. A study correlating the different packaging material properties and their relative adhesion strengths with overall package reliability in terms of both MST and T/C performance was performed. Soldermask design under the die pads was found to affect package reliability. For example, locating vias at the edge of the die is not desirable because the vias acts as initiation point for delamination and moisture-induced failure. Through die shear testing, soldermask B demonstrated higher adhesion properties compared to soldermask A across several packaging materials and enhanced the overall package reliability in terms of both MST and T/C performance. Both MST JEDEC level 1 and the T/C of 'B' and 'C' at 1000 cycles have been achieved through design and package material optimization

Materials and processes for spacecraft and high reliability applications

CERN Document Server

D Dunn, Barrie

2016-01-01

The objective of this book is to assist scientists and engineers select the ideal material or manufacturing process for particular applications; these could cover a wide range of fields, from light-weight structures to electronic hardware. The book will help in problem solving as it also presents more than 100 case studies and failure investigations from the space sector that can, by analogy, be applied to other industries. Difficult-to-find material data is included for reference. The sciences of metallic (primarily) and organic materials presented throughout the book demonstrate how they can be applied as an integral part of spacecraft product assurance schemes, which involve quality, material and processes evaluations, and the selection of mechanical and component parts. In this successor edition, which has been revised and updated, engineering problems associated with critical spacecraft hardware and the space environment are highlighted by over 500 illustrations including micrographs and fractographs. Sp...

Mechanical development for reliable reactor components

International Nuclear Information System (INIS)

Ross-Ross, P.A.; Metcalfe, R.

1983-09-01

The CANDU reactor has achieved worldwide distinction because of its reliable performance. To achieve this, special attention was given to the reliability and maintainability of components in the heavy water circuits. Development programs were initiated early in the history of the CANDU reactor to improve the effectiveness of pump seals, valves, and static seals because of unacceptable performance of the commercial equipment then available. As a result, pump seals with a five year life now appear achievable, and valves and static seals are no longer a significant concern in CANDU reactors. Increasing effort is being given remotely operated tools and fabrication systems for radioactive environments

Material and design considerations of FBGA reliability performance

Energy Technology Data Exchange (ETDEWEB)

Lee, Teck Kheng; Ng, T.C.; Chai, Y.M

2004-09-01

FBGA package reliability is usually assessed through the conventional approaches of die attach and mold compound material optimization. However, with the rapid changes and fast-moving pace of electronic packaging and the introduction of new soldermask and core materials, substrate design has also become a critical factor in determining overall package reliability. The purpose of this paper is to understand the impact design and soldermask material of a rigid substrate on overall package reliability. Three different soldermask patterns with a matrix of different die attach, mold compound, and soldermask materials are assessed using the moisture sensitivity test (MST). Package reliability is also assessed through the use of temperature cycling (T/C) at conditions 'B' and 'C'. For material optimization, three different mold compounds and die attach materials are used. Material adhesion between different die attach materials and soldermask materials are obtained through die shear performed at various temperatures and preset moisture conditions. A study correlating the different packaging material properties and their relative adhesion strengths with overall package reliability in terms of both MST and T/C performance was performed. Soldermask design under the die pads was found to affect package reliability. For example, locating vias at the edge of the die is not desirable because the vias acts as initiation point for delamination and moisture-induced failure. Through die shear testing, soldermask B demonstrated higher adhesion properties compared to soldermask A across several packaging materials and enhanced the overall package reliability in terms of both MST and T/C performance. Both MST JEDEC level 1 and the T/C of 'B' and 'C' at 1000 cycles have been achieved through design and package material optimization.

Reliability high cycle fatigue design of gas turbine blading system using probabilistic goodman diagram

Energy Technology Data Exchange (ETDEWEB)

Herman Shen, M.-H. [Ohio State Univ., Columbus, OH (United States). Dept. of Aerospace Engineering and Aviation; Nicholas, T. [MLLN, Wright-Patterson AFB, OH (United States). Air Force Research Lab.

2001-07-01

A framework for the probabilistic analysis of high cycle fatigue is developed. The framework will be useful to U.S. Air Force and aeroengine manufacturers in the design of high cycle fatigue in disk or compressor components fabricated from Ti-6Al-4V under a range of loading conditions that might be encountered during service. The main idea of the framework is to characterize vibratory stresses from random input variables due to uncertainties such as crack location, loading, material properties, and manufacturing variability. The characteristics of such vibratory stresses are portrayed graphically as histograms, or probability density function (PDF). The outcome of the probability measures associated with all the values of a random variable exceeding the material capability is achieved by a failure function g(X) defined by the difference between the vibratory stress and Goodman line or surface such that the probability of HCF failure is P{sub f} =P(g(X<0)). Design can then be based on a go-no go criterion based on an assumed risk. The framework can be used to facilitate the development of design tools for the prediction of inspection schedules and reliability in aeroengine components. Such tools could lead ultimately to improved life extension schemes in aging aircraft, and more reliable methods for the design and inspection of critical components. (orig.)

Investigations into High Temperature Components and Packaging

Energy Technology Data Exchange (ETDEWEB)

Marlino, L.D.; Seiber, L.E.; Scudiere, M.B.; M.S. Chinthavali, M.S.; McCluskey, F.P.

2007-12-31

The purpose of this report is to document the work that was performed at the Oak Ridge National Laboratory (ORNL) in support of the development of high temperature power electronics and components with monies remaining from the Semikron High Temperature Inverter Project managed by the National Energy Technology Laboratory (NETL). High temperature electronic components are needed to allow inverters to operate in more extreme operating conditions as required in advanced traction drive applications. The trend to try to eliminate secondary cooling loops and utilize the internal combustion (IC) cooling system, which operates with approximately 105 C water/ethylene glycol coolant at the output of the radiator, is necessary to further reduce vehicle costs and weight. The activity documented in this report includes development and testing of high temperature components, activities in support of high temperature testing, an assessment of several component packaging methods, and how elevated operating temperatures would impact their reliability. This report is organized with testing of new high temperature capacitors in Section 2 and testing of new 150 C junction temperature trench insulated gate bipolar transistor (IGBTs) in Section 3. Section 4 addresses some operational OPAL-GT information, which was necessary for developing module level tests. Section 5 summarizes calibration of equipment needed for the high temperature testing. Section 6 details some additional work that was funded on silicon carbide (SiC) device testing for high temperature use, and Section 7 is the complete text of a report funded from this effort summarizing packaging methods and their reliability issues for use in high temperature power electronics. Components were tested to evaluate the performance characteristics of the component at different operating temperatures. The temperature of the component is determined by the ambient temperature (i.e., temperature surrounding the device) plus the

Passive RF component technology materials, techniques, and applications

CERN Document Server

Wang, Guoan

2012-01-01

Focusing on novel materials and techniques, this pioneering volume provides you with a solid understanding of the design and fabrication of smart RF passive components. You find comprehensive details on LCP, metal materials, ferrite materials, nano materials, high aspect ratio enabled materials, green materials for RFID, and silicon micromachining techniques. Moreover, this practical book offers expert guidance on how to apply these materials and techniques to design a wide range of cutting-edge RF passive components, from MEMS switch based tunable passives and 3D passives, to metamaterial-bas

Reliability Analysis of Fatigue Fracture of Wind Turbine Drivetrain Components

DEFF Research Database (Denmark)

Berzonskis, Arvydas; Sørensen, John Dalsgaard

2016-01-01

in the volume of the casted ductile iron main shaft, on the reliability of the component. The probabilistic reliability analysis conducted is based on fracture mechanics models. Additionally, the utilization of the probabilistic reliability for operation and maintenance planning and quality control is discussed....

Research on optimizing components of microfine high-performance composite cementitious materials

International Nuclear Information System (INIS)

Hu Shuguang; Guan Xuemao; Ding Qingjun

2002-01-01

The relationship between material components and mechanical properties was studied in terms of composite material principles and orthogonal experimental design. Moreover, the microstructure of microfine high-performance composite cementitious material (MHPCC) paste was investigated by means of scanning electron microscopy (SEM) methods. The results showed that the composite material consisting of blast furnace slag (BFS), gypsum (G 2 ) and expansive agent (EA) could obviously improve the strength of the cementitious material containing 40% fly ash (FA). Although microfine cement (MC) was merely 45% percent of the MHPCC, the compressive strength of MHPCC paste was higher than that of neat MC paste. BFS played an important role in MHPCC. The optimum-added quantity of BFS was 15%. The needle-shaped ettringite obtained from the EA reacting with Ca(OH) 2 forms a three-dimensional network structure, which not only improved the early strength of MHPCC paste but also increased its late strength. The reason was that the network structure, which was similar to a fiber-reinforced composite, was formed in the late period of hydration with the progress of hydration and the deposition of hydration products into the network structure

Development of the software for the component reliability database system of Korean nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Han, Sang Hoon; Kim, Seung Hwan; Choi, Sun Young [Korea Atomic Energy Research Institute, Taejeon (Korea)

2002-03-01

A study was performed to develop the system for the component reliability database which consists of database system to store the reliability data and softwares to analyze the reliability data.This system is a part of KIND (Korea Information System for Nuclear Reliability Database).The MS-SQL database is used to stores the component population data, component maintenance history, and the results of reliability analysis. Two softwares were developed for the component reliability system. One is the KIND-InfoView for the data storing, retrieving and searching. The other is the KIND-CompRel for the statistical analysis of component reliability. 4 refs., 13 figs., 7 tabs. (Author)

Nuclear plant reliability data system. 1979 annual reports of cumulative system and component reliability

International Nuclear Information System (INIS)

1979-01-01

The primary purposes of the information in these reports are the following: to provide operating statistics of safety-related systems within a unit which may be used to compare and evaluate reliability performance and to provide failure mode and failure rate statistics on components which may be used in failure mode effects analysis, fault hazard analysis, probabilistic reliability analysis, and so forth

Design and Fabrication Technique of the Key Components for Very High Temperature Reactor

Energy Technology Data Exchange (ETDEWEB)

Lee, Ho Jin; Song, Ki Nam; Kim, Yong Wan

2006-12-15

The gas outlet temperature of Very High Temperature Reactor (VHTR) may be beyond the capability of conventional metallic materials. The requirement of the gas outlet temperature of 950 .deg. C will result in operating temperatures for metallic core components that will approach very high temperature on some cases. The materials that are capable of withstanding this temperature should be prepared, or nonmetallic materials will be required for limited components. The Ni-base alloys such as Alloy 617, Hastelloy X, XR, Incoloy 800H, and Haynes 230 are being investigated to apply them on components operated in high temperature. Currently available national and international codes and procedures are needed reviewed to design the components for HTGR/VHTR. Seven codes and procedures, including five ASME Codes and Code cases, one French code (RCC-MR), and on British Procedure (R5) were reviewed. The scope of the code and code cases needs to be expanded to include the materials with allowable temperatures of 950 .deg. C and higher. The selection of compact heat exchangers technology depends on the operating conditions such as pressure, flow rates, temperature, but also on other parameters such as fouling, corrosion, compactness, weight, maintenance and reliability. Welding, brazing, and diffusion bonding are considered proper joining processes for the heat exchanger operating in the high temperature and high pressure conditions without leakage. Because VHTRs require high temperature operations, various controlled materials, thick vessels, dissimilar metal joints, and precise controls of microstructure in weldment, the more advanced joining processes are needed than PWRs. The improved solid joining techniques are considered for the IHX fabrication. The weldability for Alloy 617 and Haynes 230 using GTAW and SMAW processes was investigated by CEA.

Design and Fabrication Technique of the Key Components for Very High Temperature Reactor

International Nuclear Information System (INIS)

Lee, Ho Jin; Song, Ki Nam; Kim, Yong Wan

2006-12-01

The gas outlet temperature of Very High Temperature Reactor (VHTR) may be beyond the capability of conventional metallic materials. The requirement of the gas outlet temperature of 950 .deg. C will result in operating temperatures for metallic core components that will approach very high temperature on some cases. The materials that are capable of withstanding this temperature should be prepared, or nonmetallic materials will be required for limited components. The Ni-base alloys such as Alloy 617, Hastelloy X, XR, Incoloy 800H, and Haynes 230 are being investigated to apply them on components operated in high temperature. Currently available national and international codes and procedures are needed reviewed to design the components for HTGR/VHTR. Seven codes and procedures, including five ASME Codes and Code cases, one French code (RCC-MR), and on British Procedure (R5) were reviewed. The scope of the code and code cases needs to be expanded to include the materials with allowable temperatures of 950 .deg. C and higher. The selection of compact heat exchangers technology depends on the operating conditions such as pressure, flow rates, temperature, but also on other parameters such as fouling, corrosion, compactness, weight, maintenance and reliability. Welding, brazing, and diffusion bonding are considered proper joining processes for the heat exchanger operating in the high temperature and high pressure conditions without leakage. Because VHTRs require high temperature operations, various controlled materials, thick vessels, dissimilar metal joints, and precise controls of microstructure in weldment, the more advanced joining processes are needed than PWRs. The improved solid joining techniques are considered for the IHX fabrication. The weldability for Alloy 617 and Haynes 230 using GTAW and SMAW processes was investigated by CEA

The prediction of reliability and residual life of reactor pressure components

International Nuclear Information System (INIS)

Nemec, J.; Antalovsky, S.

1978-01-01

The paper deals with the problem of PWR pressure components reliability and residual life evaluation and prediction. A physical model of damage cumulation which serves as a theoretical basis for all considerations presents two major aspects. The first one describes the dependence of the degree of damage in the crack leading-edge in pressure components on the reactor system load-time history, i.e. on the number of transient loads. Both stages, fatigue crack initiation and growth through the wall until the critical length is reached, are investigated. The crack is supposed to initiate at the flaws in a strength weld joint or in the bimetallic weld of the base ferritic steel and the austenitic stainless overlay cladding. The growth rates of developed cracks are analysed in respect to different load-time histories. Important cyclic properties of some steels are derived from the low-cycle fatigue theory. The second aspect is the load-time history-dependent process of precipitation, deformation and radiation aging, characterized entirely by the critical crack-length value mentioned above. The fracture point, defined by the equation ''crack-length=critical value'' and hence the residual life, can be evaluated using this model and verified by in-service inspection. The physical model described is randomized by considering all the parameters of the model as random. Monte Carlo methods are applied and fatigue crack initiation and growth is simulated. This permits evaluation of the reliability and residual life of the component. The distributions of material and load-time history parameters are needed for such simulation. Both the deterministic and computer-simulated probabilistic predictions of reliability and residual life are verified by prior-to-failure sequential testing of data coming from in-service NDT periodical inspections. (author)

Availability, reliability and downtime of systems with repairable components

DEFF Research Database (Denmark)

Kiureghian, Armen Der; Ditlevsen, Ove Dalager; Song, J.

2007-01-01

Closed-form expressions are derived for the steady-state availability, mean rate of failure, mean duration of downtime and lower bound reliability of a general system with randomly and independently failing repairable components. Component failures are assumed to be homogeneous Poisson events in ...

Development status of component reliability database for Korean NPPs and a case study

International Nuclear Information System (INIS)

Choi, S. Y.; Yang, S. H.; Lee, S. C.; Kim, S. H.; Han, S. H.

1999-01-01

We have applied a generic database to the PSA (Probabilistic Safety Assessment) for the Korean Standard NPPs (Nuclear Power Plant) since there is no specific component reliability database. However generic data is not enough to reflect the specific characteristics of domestic plants since it is collected by foreign plants. Therefore we are developing the plant-specific component reliability database for domestic NPPs. In this paper, we describe the development status of the component reliability database and the approach method of data collection and component failure analysis. We also summarize a case study of component failure analysis. We first collect the failure and repair data from the TR (Trouble Report) electronic database and the daily operation report sheet. Now we add a data collection method that checks the original TR sheet to improve the data quality. We input the component failure and repair data of principal components of about 30 systems into the component reliability database. Now, we are analyzing the component failure data of 11 safety systems among the systems to calculate component failure rate and unavailability etc

Quality assurance in ceramic materials and components. High-resolution non-destructive testing especially of ceramic surfaces

International Nuclear Information System (INIS)

Reiter, H.; Hoffmann, B.; Morsch, A.; Arnold, W.; Schneider, E.

1988-01-01

This report discusses the influence of defects on the failure behavior of ceramic materials under four-point bending stress. In this connection various Si 3 N 4 and SiC materials with and without artificially introduced defect particles (Fe, WC, Si, pores) were examined by the following non-destructive test methods: photoacoustic microscopy, scanning laser acoustic microscopy, microfocus roentgenoscopy and ultrasound transit-time measurements. Finally, a four-point bending test and a fracture-mechanical evaluation of the fracture-incuding defects were carried out at the Institute for reliability and failure studies in mechanical engineering of the University of Karlsruhe. According to the type of stress the samples predominantly failed in the case of defects in the surface zone of the side in tension. Among the ndt methods applied the photoacoustic microscopy as a typical surface testing method could predict most of the fracture-inducing defects (30-50 %) without causing destruction. In this connection a different detection sensitivity which corresponds to the thermal reflection factors became apparent according to the type of defect. Furthermore the reports describes the results of some preliminary tests on ndt of green ceramics. In these investigations both the microfocus roentgenoscopy test and the roentgen computed tomography showed a high potential of detecting inhomogeneities and defects in green Si 3 N 4 and SiC components. (orig.) [de

Reliability Analysis of Load-Sharing K-out-of-N System Considering Component Degradation

Directory of Open Access Journals (Sweden)

Chunbo Yang

2015-01-01

Full Text Available The K-out-of-N configuration is a typical form of redundancy techniques to improve system reliability, where at least K-out-of-N components must work for successful operation of system. When the components are degraded, more components are needed to meet the system requirement, which means that the value of K has to increase. The current reliability analysis methods overestimate the reliability, because using constant K ignores the degradation effect. In a load-sharing system with degrading components, the workload shared on each surviving component will increase after a random component failure, resulting in higher failure rate and increased performance degradation rate. This paper proposes a method combining a tampered failure rate model with a performance degradation model to analyze the reliability of load-sharing K-out-of-N system with degrading components. The proposed method considers the value of K as a variable which is derived by the performance degradation model. Also, the load-sharing effect is evaluated by the tampered failure rate model. Monte-Carlo simulation procedure is used to estimate the discrete probability distribution of K. The case of a solar panel is studied in this paper, and the result shows that the reliability considering component degradation is less than that ignoring component degradation.

Material and component progress within ARCHER for advanced high temperature reactor

International Nuclear Information System (INIS)

Buckthorpe, D.E.; Davies, M.; Pra, F.; Bonnamy, P.; Fokkens, J.; Heijna, M.; Bout, N. de; Vreeling, A.; Bourlier, F.; Lhachemi, D.; Woayehune, A.; Dubiez-le-Goff, S.; Hahner, P.; Futterer, M.; Berka, J.; Kalivodora, J.; Pouchon, M.A.; Schmitt, R.; Homerin, P.; Marsden, B.; Mummery, P.; Mutch, G.; Ponca, D.; Buhl, P.; Hoffmann, M.; Rondet, F.; Pecherty, A.; Baurand, F.; Alenda, F.; Esch, M.; Kohlz, N.; Reed, J.; Fachinger, J.; Klower, Dr.

2014-01-01

The ARCHER (Advanced High-Temperature Reactors for Cogeneration of Heat and Electricity R and D) integrated project started in 2011 as part of the European Commission 7. Framework Programme (FP7) for a period of four years to perform High Temperature Reactor technology R and D in support of reactor demonstration. The project consortium encompasses conventional and Nuclear Industry, Utilities, Technical Support Organizations, Research and Development Organizations and Academia. The activities involved contribute to the Generation IV (GIF) International Forum and collaborate with related projects in the US, China, Japan, and the Republic of Korea in cooperation with IAEA and ISTC. This paper addresses the progress of the work on materials and component technologies within ARCHER over the first two years of the project. (authors)

Component aging and reliability trends in Loviisa Nuclear Power Plant

International Nuclear Information System (INIS)

Jankala, K.E.; Vaurio, J.K.

1989-01-01

A plant-specific reliability data collection and analysis system has been developed at the Loviisa Nuclear Power Plant to perform tests for component aging and analysis of reliability trends. The system yields both mean values an uncertainty distribution information for reliability parameters to be used in the PSA project underway and in living-PSA applications. Several different trend models are included in the reliability analysis system. Simple analytical expressions have been derived from the parameters of these models, and their variances have been obtained using the information matrix. This paper is focused on the details of the learning/aging models and the estimation of their parameters and statistical accuracies. Applications to the historical data of the Loviisa plant are presented. The results indicate both up- and down-trends in failure rates as well as individuality between nominally identical components

Materials reliability in the back end of the nuclear fuel cycle

International Nuclear Information System (INIS)

1987-05-01

Operating experience of nuclear fuel cycle facilities has proved that the performance and availability of key equipment largely depend on the reliability of its construction materials. In general, the materials of construction have performed well in accordance with the design criteria of equipment. In some cases, however, materials failure problems have been encountered, the causes of which are related to their corrosion and mechanical degradation. In response to the growing interest in these topics, the IAEA convened the Technical Committee Meeting on ''Materials Reliability in the Back-End of the Nuclear Fuel Cycle'' at its Headquarters from September 2 to 5, 1986. This Technical Document contains the 15 papers presented during the Meeting. Material aspects of the following fields of the back-end of the nuclear fuel cycle are covered: interim and long-term storage of spent fuel; final disposal of spent fuel; storage and vitrification of High Level Liquid Wastes (HLLW); long-term storage of High Level Wastes (HLW); and spent fuel treatment

High-Reliability Health Care: Getting There from Here

Science.gov (United States)

Chassin, Mark R; Loeb, Jerod M

2013-01-01

Context Despite serious and widespread efforts to improve the quality of health care, many patients still suffer preventable harm every day. Hospitals find improvement difficult to sustain, and they suffer “project fatigue” because so many problems need attention. No hospitals or health systems have achieved consistent excellence throughout their institutions. High-reliability science is the study of organizations in industries like commercial aviation and nuclear power that operate under hazardous conditions while maintaining safety levels that are far better than those of health care. Adapting and applying the lessons of this science to health care offer the promise of enabling hospitals to reach levels of quality and safety that are comparable to those of the best high-reliability organizations. Methods We combined the Joint Commission's knowledge of health care organizations with knowledge from the published literature and from experts in high-reliability industries and leading safety scholars outside health care. We developed a conceptual and practical framework for assessing hospitals’ readiness for and progress toward high reliability. By iterative testing with hospital leaders, we refined the framework and, for each of its fourteen components, defined stages of maturity through which we believe hospitals must pass to reach high reliability. Findings We discovered that the ways that high-reliability organizations generate and maintain high levels of safety cannot be directly applied to today's hospitals. We defined a series of incremental changes that hospitals should undertake to progress toward high reliability. These changes involve the leadership's commitment to achieving zero patient harm, a fully functional culture of safety throughout the organization, and the widespread deployment of highly effective process improvement tools. Conclusions Hospitals can make substantial progress toward high reliability by undertaking several specific

Reliability of thermal interface materials: A review

International Nuclear Information System (INIS)

Due, Jens; Robinson, Anthony J.

2013-01-01

Thermal interface materials (TIMs) are used extensively to improve thermal conduction across two mating parts. They are particularly crucial in electronics thermal management since excessive junction-to-ambient thermal resistances can cause elevated temperatures which can negatively influence device performance and reliability. Of particular interest to electronic package designers is the thermal resistance of the TIM layer at the end of its design life. Estimations of this allow the package to be designed to perform adequately over its entire useful life. To this end, TIM reliability studies have been performed using accelerated stress tests. This paper reviews the body of work which has been performed on TIM reliability. It focuses on the various test methodologies with commentary on the results which have been obtained for the different TIM materials. Based on the information available in the open literature, a test procedure is proposed for TIM selection based on beginning and end of life performance. - Highlights: ► This paper reviews the body of work which has been performed on TIM reliability. ► Test methodologies for reliability testing are outlined. ► Reliability results for the different TIM materials are discussed. ► A test procedure is proposed for TIM selection BOLife and EOLife performance.

The reliability of test results from simple test samples in predicting the fatigue performance of automotive components

International Nuclear Information System (INIS)

Fourlaris, G.; Ellwood, R.; Jones, T.B.

2007-01-01

The use of high strength steels (HSS) in automotive components is steadily increasing as automotive designers use modern steel grades to improve structural performance, reduce vehicle weight and enhance crash performance. Weight reduction can be achieved by substituting mild steel with a thinner gauge HSS, however, it must be ensured that no deterioration in performance including fatigue capability occurs. In this study, tests have been carried out to determine the effects that gauge and material strength have on the fatigue performance of a fusion welded automotive suspension arm. Current finite element (FE) modelling and fatigue prediction techniques have been evaluated to determine their reliability when used for thin strip steels. Results have shown the fatigue performance of welded components to be independent of the strength of the parent material for the steel grades studied, with material thickness and joining process the key features determining the fatigue performance. The correlation between the fatigue performance of simple welded samples under uniaxial, constant amplitude loading and complex components under biaxial in service road load data, has been shown to be unreliable. This study also indicates that with the application of modern technologies, such as tailor-welded blanks (TWB), significant weight savings can be achieved. This is demonstrated by a 19% weight reduction with no detrimental effect on the fatigue performance

Reliability analysis of component-level redundant topologies for solid-state fault current limiter

Science.gov (United States)

Farhadi, Masoud; Abapour, Mehdi; Mohammadi-Ivatloo, Behnam

2018-04-01

Experience shows that semiconductor switches in power electronics systems are the most vulnerable components. One of the most common ways to solve this reliability challenge is component-level redundant design. There are four possible configurations for the redundant design in component level. This article presents a comparative reliability analysis between different component-level redundant designs for solid-state fault current limiter. The aim of the proposed analysis is to determine the more reliable component-level redundant configuration. The mean time to failure (MTTF) is used as the reliability parameter. Considering both fault types (open circuit and short circuit), the MTTFs of different configurations are calculated. It is demonstrated that more reliable configuration depends on the junction temperature of the semiconductor switches in the steady state. That junction temperature is a function of (i) ambient temperature, (ii) power loss of the semiconductor switch and (iii) thermal resistance of heat sink. Also, results' sensitivity to each parameter is investigated. The results show that in different conditions, various configurations have higher reliability. The experimental results are presented to clarify the theory and feasibility of the proposed approaches. At last, levelised costs of different configurations are analysed for a fair comparison.

Reliability and integrity management program for PBMR helium pressure boundary components - HTR2008-58036

International Nuclear Information System (INIS)

Fleming, K. N.; Gamble, R.; Gosselin, S.; Fletcher, J.; Broom, N.

2008-01-01

The purpose of this paper is to present the results of a study to establish strategies for the reliability and integrity management (RIM) of passive metallic components for the PBMR. The RIM strategies investigated include design elements, leak detection and testing approaches, and non-destructive examinations. Specific combinations of strategies are determined to be necessary and sufficient to achieve target reliability goals for passive components. This study recommends a basis for the RIM program for the PBMR Demonstration Power Plant (DPP) and provides guidance for the development by the American Society of Mechanical Engineers (ASME) of RIM requirements for Modular High Temperature Gas-Cooled Reactors (MHRs). (authors)

Root cause analysis in support of reliability enhancement of engineering components

International Nuclear Information System (INIS)

Kumar, Sachin; Mishra, Vivek; Joshi, N.S.; Varde, P.V.

2014-01-01

Reliability based methods have been widely used for the safety assessment of plant system, structures and components. These methods provide a quantitative estimation of system reliability but do not give insight into the failure mechanism. Understanding the failure mechanism is a must to avoid the recurrence of the events and enhancement of the system reliability. Root cause analysis provides a tool for gaining detailed insights into the causes of failure of component with particular attention to the identification of fault in component design, operation, surveillance, maintenance, training, procedures and policies which must be improved to prevent repetition of incidents. Root cause analysis also helps in developing Probabilistic Safety Analysis models. A probabilistic precursor study provides a complement to the root cause analysis approach in event analysis by focusing on how an event might have developed adversely. This paper discusses the root cause analysis methodologies and their application in the specific case studies for enhancement of system reliability. (author)

High-reliability computing for the smarter planet

International Nuclear Information System (INIS)

Quinn, Heather M.; Graham, Paul; Manuzzato, Andrea; Dehon, Andre

2010-01-01

The geometric rate of improvement of transistor size and integrated circuit performance, known as Moore's Law, has been an engine of growth for our economy, enabling new products and services, creating new value and wealth, increasing safety, and removing menial tasks from our daily lives. Affordable, highly integrated components have enabled both life-saving technologies and rich entertainment applications. Anti-lock brakes, insulin monitors, and GPS-enabled emergency response systems save lives. Cell phones, internet appliances, virtual worlds, realistic video games, and mp3 players enrich our lives and connect us together. Over the past 40 years of silicon scaling, the increasing capabilities of inexpensive computation have transformed our society through automation and ubiquitous communications. In this paper, we will present the concept of the smarter planet, how reliability failures affect current systems, and methods that can be used to increase the reliable adoption of new automation in the future. We will illustrate these issues using a number of different electronic devices in a couple of different scenarios. Recently IBM has been presenting the idea of a 'smarter planet.' In smarter planet documents, IBM discusses increased computer automation of roadways, banking, healthcare, and infrastructure, as automation could create more efficient systems. A necessary component of the smarter planet concept is to ensure that these new systems have very high reliability. Even extremely rare reliability problems can easily escalate to problematic scenarios when implemented at very large scales. For life-critical systems, such as automobiles, infrastructure, medical implantables, and avionic systems, unmitigated failures could be dangerous. As more automation moves into these types of critical systems, reliability failures will need to be managed. As computer automation continues to increase in our society, the need for greater radiation reliability is necessary

High-reliability computing for the smarter planet

Energy Technology Data Exchange (ETDEWEB)

Quinn, Heather M [Los Alamos National Laboratory; Graham, Paul [Los Alamos National Laboratory; Manuzzato, Andrea [UNIV OF PADOVA; Dehon, Andre [UNIV OF PENN; Carter, Nicholas [INTEL CORPORATION

2010-01-01

The geometric rate of improvement of transistor size and integrated circuit performance, known as Moore's Law, has been an engine of growth for our economy, enabling new products and services, creating new value and wealth, increasing safety, and removing menial tasks from our daily lives. Affordable, highly integrated components have enabled both life-saving technologies and rich entertainment applications. Anti-lock brakes, insulin monitors, and GPS-enabled emergency response systems save lives. Cell phones, internet appliances, virtual worlds, realistic video games, and mp3 players enrich our lives and connect us together. Over the past 40 years of silicon scaling, the increasing capabilities of inexpensive computation have transformed our society through automation and ubiquitous communications. In this paper, we will present the concept of the smarter planet, how reliability failures affect current systems, and methods that can be used to increase the reliable adoption of new automation in the future. We will illustrate these issues using a number of different electronic devices in a couple of different scenarios. Recently IBM has been presenting the idea of a 'smarter planet.' In smarter planet documents, IBM discusses increased computer automation of roadways, banking, healthcare, and infrastructure, as automation could create more efficient systems. A necessary component of the smarter planet concept is to ensure that these new systems have very high reliability. Even extremely rare reliability problems can easily escalate to problematic scenarios when implemented at very large scales. For life-critical systems, such as automobiles, infrastructure, medical implantables, and avionic systems, unmitigated failures could be dangerous. As more automation moves into these types of critical systems, reliability failures will need to be managed. As computer automation continues to increase in our society, the need for greater radiation reliability is

Reliability Prediction Of System And Component Of Process System Of RSG-GAS Reactor

International Nuclear Information System (INIS)

Sitorus Pane, Jupiter

2001-01-01

The older the reactor the higher the probability of the system and components suffer from loss of function or degradation. This phenomenon occurred because of wear, corrosion, and fatigue. Study on component reliability was generally performed deterministically and statistically. This paper would describe an analysis of using statistical method, i.e. regression Cox, in order to predict the reliability of the components and their environmental influence's factors. The result showed that the dynamics, non safety related, and mechanic components have higher risk of failure, whereas static, safety related, and electric have lower risk of failures. The relative risk value for variable of components dynamics, quality, dummy 1 and dummy 2 are of 1.54, 1.59, 1.50, and 0.83 compare to other components type with each variable. Component with the higher risk have lower reliability than lower one

Material and construction of primary components

International Nuclear Information System (INIS)

Kaser, A.; Wallner, F.

1978-01-01

The construction of SNR's requires specific properties of the materials, i.e. high strength at temperatures of 600 0 C, adequate creep rupture strength, low long-time embrittlement. Aspects are given for optimalization of the mentioned properties with regard to safe manufacture especially good weldability. The austenitic material X6CrNil811 similar the type AISI 304 SS finally was chosen. Besides the fundamental analysis of the material properties it will be reported about the experiences gained during the manufacturing of the essential components. (author)

Reliability analysis and component functional allocations for the ESF multi-loop controller design

International Nuclear Information System (INIS)

Hur, Seop; Kim, D.H.; Choi, J.K.; Park, J.C.; Seong, S.H.; Lee, D.Y.

2006-01-01

This paper deals with the reliability analysis and component functional allocations to ensure the enhanced system reliability and availability. In the Engineered Safety Features, functionally dependent components are controlled by a multi-loop controller. The system reliability of the Engineered Safety Features-Component Control System, especially, the multi-loop controller which is changed comparing to the conventional controllers is an important factor for the Probability Safety Assessment in the nuclear field. To evaluate the multi-loop controller's failure rate of the k-out-of-m redundant system, the binomial process is used. In addition, the component functional allocation is performed to tolerate a single multi-loop controller failure without the loss of vital operation within the constraints of the piping and component configuration, and ensure that mechanically redundant components remain functional. (author)

High-Reliable PLC RTOS Development and RPS Structure Analysis

Energy Technology Data Exchange (ETDEWEB)

Sohn, H. S.; Song, D. Y.; Sohn, D. S.; Kim, J. H. [Enersys Co., Daejeon (Korea, Republic of)

2008-04-15

One of the KNICS objectives is to develop a platform for Nuclear Power Plant(NPP) I and C(Instrumentation and Control) system, especially plant protection system. The developed platform is POSAFE-Q and this work supports the development of POSAFE-Q with the development of high-reliable real-time operating system(RTOS) and programmable logic device(PLD) software. Another KNICS objective is to develop safety I and C systems, such as Reactor Protection System(RPS) and Engineered Safety Feature-Component Control System(ESF-CCS). This work plays an important role in the structure analysis for RPS. Validation and verification(V and V) of the safety critical software is an essential work to make digital plant protection system highly reliable and safe. Generally, the reliability and safety of software based system can be improved by strict quality assurance framework including the software development itself. In other words, through V and V, the reliability and safety of a system can be improved and the development activities like software requirement specification, software design specification, component tests, integration tests, and system tests shall be appropriately documented for V and V.

High-Reliable PLC RTOS Development and RPS Structure Analysis

International Nuclear Information System (INIS)

Sohn, H. S.; Song, D. Y.; Sohn, D. S.; Kim, J. H.

2008-04-01

One of the KNICS objectives is to develop a platform for Nuclear Power Plant(NPP) I and C(Instrumentation and Control) system, especially plant protection system. The developed platform is POSAFE-Q and this work supports the development of POSAFE-Q with the development of high-reliable real-time operating system(RTOS) and programmable logic device(PLD) software. Another KNICS objective is to develop safety I and C systems, such as Reactor Protection System(RPS) and Engineered Safety Feature-Component Control System(ESF-CCS). This work plays an important role in the structure analysis for RPS. Validation and verification(V and V) of the safety critical software is an essential work to make digital plant protection system highly reliable and safe. Generally, the reliability and safety of software based system can be improved by strict quality assurance framework including the software development itself. In other words, through V and V, the reliability and safety of a system can be improved and the development activities like software requirement specification, software design specification, component tests, integration tests, and system tests shall be appropriately documented for V and V.

High-reliability health care: getting there from here.

Science.gov (United States)

Chassin, Mark R; Loeb, Jerod M

2013-09-01

Despite serious and widespread efforts to improve the quality of health care, many patients still suffer preventable harm every day. Hospitals find improvement difficult to sustain, and they suffer "project fatigue" because so many problems need attention. No hospitals or health systems have achieved consistent excellence throughout their institutions. High-reliability science is the study of organizations in industries like commercial aviation and nuclear power that operate under hazardous conditions while maintaining safety levels that are far better than those of health care. Adapting and applying the lessons of this science to health care offer the promise of enabling hospitals to reach levels of quality and safety that are comparable to those of the best high-reliability organizations. We combined the Joint Commission's knowledge of health care organizations with knowledge from the published literature and from experts in high-reliability industries and leading safety scholars outside health care. We developed a conceptual and practical framework for assessing hospitals' readiness for and progress toward high reliability. By iterative testing with hospital leaders, we refined the framework and, for each of its fourteen components, defined stages of maturity through which we believe hospitals must pass to reach high reliability. We discovered that the ways that high-reliability organizations generate and maintain high levels of safety cannot be directly applied to today's hospitals. We defined a series of incremental changes that hospitals should undertake to progress toward high reliability. These changes involve the leadership's commitment to achieving zero patient harm, a fully functional culture of safety throughout the organization, and the widespread deployment of highly effective process improvement tools. Hospitals can make substantial progress toward high reliability by undertaking several specific organizational change initiatives. Further research

Reliability Assessment of IGBT Modules Modeled as Systems with Correlated Components

DEFF Research Database (Denmark)

Kostandyan, Erik; Sørensen, John Dalsgaard

2013-01-01

configuration. The estimated system reliability by the proposed method is a conservative estimate. Application of the suggested method could be extended for reliability estimation of systems composing of welding joints, bolts, bearings, etc. The reliability model incorporates the correlation between...... was applied for the systems failure functions estimation. It is desired to compare the results with the true system failure function, which is possible to estimate using simulation techniques. Theoretical model development should be applied for the further research. One of the directions for it might...... be modeling the system based on the Sequential Order Statistics, by considering the failure of the minimum (weakest component) at each loading level. The proposed idea to represent the system by the independent components could also be used for modeling reliability by Sequential Order Statistics....

An Intuitionistic Fuzzy Methodology for Component-Based Software Reliability Optimization

DEFF Research Database (Denmark)

Madsen, Henrik; Grigore, Albeanu; Popenţiuvlǎdicescu, Florin

2012-01-01

Component-based software development is the current methodology facilitating agility in project management, software reuse in design and implementation, promoting quality and productivity, and increasing the reliability and performability. This paper illustrates the usage of intuitionistic fuzzy...... degree approach in modelling the quality of entities in imprecise software reliability computing in order to optimize management results. Intuitionistic fuzzy optimization algorithms are proposed to be used for complex software systems reliability optimization under various constraints....

Reliability of mechanical components subjected to combined alternating and mean stresses with a nonconstant stress ratio

International Nuclear Information System (INIS)

Kececioglu, D.; Lamarre, G.B.

1979-01-01

The reliability of reactor mechanical components and structural members, submitted to external loads which induce alternating bending stresses and mean shear stresses at the critical section where failure has a high probability of occurring, is predicted assuming that the ratio of the distributed alternating stress to the mean stress is also distributed and yields a bivariate failure-governing, combined alternating and mean, stress distribution. A computer programmed methodology is developed to calculate the reliability under these conditions given the associated distributional Goodman diagram for a reactor component or structural member. (orig.)

Human reliability program: Components and effects

International Nuclear Information System (INIS)

Baley-Downes, S.

1986-01-01

The term ''Human Reliability Program'' (HRP) is defined as a series of selective controls which are implemented and integrated to identify the ''insider threat'' from current and prospective employees who are dishonest, disloyal and unreliable. The HRP, although not a prediction of human behaviour, is an excellent tool for decision making and should compliment security and improve employee quality. The HRP consists of several component applications such as management evaluation; appropriate background investigative requirements; occupational health examination and laboratory testing; drug/alcohol screening; psychological testing and interviews; polygraph examination; job related aberrant behaviour recognition; on-going education and training; document control; drug/alcohol rehabilitation; periodic HRP audit; and implementation of an onsite central clearing house. The components and effects of HRP are discussed in further detail in this paper

Reliability considerations of electronics components for the deep underwater muon and neutrino detection system

International Nuclear Information System (INIS)

Leskovar, B.

1980-02-01

The reliability of some electronics components for the Deep Underwater Muon and Neutrino Detection (DUMAND) System is discussed. An introductory overview of engineering concepts and technique for reliability assessment is given. Component reliability is discussed in the contest of major factors causing failures, particularly with respect to physical and chemical causes, process technology and testing, and screening procedures. Failure rates are presented for discrete devices and for integrated circuits as well as for basic electronics components. Furthermore, the military reliability specifications and standards for semiconductor devices are reviewed

High-temperature materials and structural ceramics

International Nuclear Information System (INIS)

1990-01-01

This report gives a survey of research work in the area of high-temperature materials and structural ceramics of the KFA (Juelich Nuclear Research Center). The following topics are treated: (1) For energy facilities: ODS materials for gas turbine blades and heat exchangers; assessment of the remaining life of main steam pipes, material characterization and material stress limits for First-Wall components; metallic and graphitic materials for high-temperature reactors. (2) For process engineering plants: composites for reformer tubes and cracking tubes; ceramic/ceramic joints and metal/ceramic and metal/metal joints; Composites and alloys for rolling bearing and sliding systems up to application temperatures of 1000deg C; high-temperature corrosion of metal and ceramic material; porous ceramic high-temperature filters and moulding coat-mix techniques; electrically conducting ceramic material (superconductors, fuel cells, solid electrolytes); high-temperature light sources (high-temperature chemistry); oil vapor engines with caramic components; ODS materials for components in diesel engines and vehicle gas turbines. (MM) [de

Division of Development and Technology Plasma/Materials Interaction and High Heat Flux Materials and Components Task Groups: Report on the joint meeting, July 9, 1986

International Nuclear Information System (INIS)

Watson, R.D.

1986-09-01

This paper contains a collection of viewgraphs from a joint meeting of the Division of Development and Technology Plasma/Materials Interaction and High Heat Flux Materials and Components Task Groups. A list of contributing topics is: PPPL update, ATF update, Los Alamos RFP program update, status of DIII-D, PMI graphite studies at ORNL, PMI studies for low atomic number materials, high heat flux materials issues, high heat flux testing program, particle confinement in tokamaks, helium self pumping, self-regenerating coatings technical planning activity and international collaboration update

Generic component reliability data for research reactors PSA. Final report of the CRP on data acquisition for research reactor PSA. Working material

International Nuclear Information System (INIS)

1993-01-01

The scope of this document is to provide the final reference generic component reliability database information for a variety of research reactor types. As noted in Section 2.1 and Table 3a, many years of component data are represented in the database so that it is expected that the report should provide representative data valid for a number of years. The database provides component failure rates on a time and/or a demand related basis according to the operational modes of the components. At the current time an update of the database is not planned. As a result of the implementation of data collection systems in the research reactors represented in these studies, updating of data from individual facilities could be made available from the contributing research reactor facilities themselves. As noted in Section 1.2, the report does not include detailed discussion of information regarding component classification and reliability parameter definitions. The report does provide some insights and discussion regarding the practicalities of the data collection process and some guidelines for database usage. 9 refs, tabs

Generic component reliability data for research reactors PSA. Final report of the CRP on data acquisition for research reactor PSA. Working material

Energy Technology Data Exchange (ETDEWEB)

NONE

1994-12-31

The scope of this document is to provide the final reference generic component reliability database information for a variety of research reactor types. As noted in Section 2.1 and Table 3a, many years of component data are represented in the database so that it is expected that the report should provide representative data valid for a number of years. The database provides component failure rates on a time and/or a demand related basis according to the operational modes of the components. At the current time an update of the database is not planned. As a result of the implementation of data collection systems in the research reactors represented in these studies, updating of data from individual facilities could be made available from the contributing research reactor facilities themselves. As noted in Section 1.2, the report does not include detailed discussion of information regarding component classification and reliability parameter definitions. The report does provide some insights and discussion regarding the practicalities of the data collection process and some guidelines for database usage. 9 refs, tabs.

Summary of component reliability data for probabilistic safety analysis of Korean standard nuclear power plant

International Nuclear Information System (INIS)

Choi, S. Y.; Han, S. H.

2004-01-01

The reliability data of Korean NPP that reflects the plant specific characteristics is necessary for PSA of Korean nuclear power plants. We have performed a study to develop the component reliability DB and S/W for component reliability analysis. Based on the system, we had have collected the component operation data and failure/repair data during plant operation data to 1998/2000 for YGN 3,4/UCN 3,4 respectively. Recently, we have upgraded the database by collecting additional data by 2002 for Korean standard nuclear power plants and performed component reliability analysis and Bayesian analysis again. In this paper, we supply the summary of component reliability data for probabilistic safety analysis of Korean standard nuclear power plant and describe the plant specific characteristics compared to the generic data

Design Optimization Method for Composite Components Based on Moment Reliability-Sensitivity Criteria

Science.gov (United States)

Sun, Zhigang; Wang, Changxi; Niu, Xuming; Song, Yingdong

2017-08-01

In this paper, a Reliability-Sensitivity Based Design Optimization (RSBDO) methodology for the design of the ceramic matrix composites (CMCs) components has been proposed. A practical and efficient method for reliability analysis and sensitivity analysis of complex components with arbitrary distribution parameters are investigated by using the perturbation method, the respond surface method, the Edgeworth series and the sensitivity analysis approach. The RSBDO methodology is then established by incorporating sensitivity calculation model into RBDO methodology. Finally, the proposed RSBDO methodology is applied to the design of the CMCs components. By comparing with Monte Carlo simulation, the numerical results demonstrate that the proposed methodology provides an accurate, convergent and computationally efficient method for reliability-analysis based finite element modeling engineering practice.

Sodium component reliability data collection at CREDO

International Nuclear Information System (INIS)

Bott, T.F.; Haas, P.M.; Manning, J.J.

1979-01-01

The Centralized Reliability Data Organization (CREDO) has been established at Oak Ridge National Laboratory (ORNL) by the Department of Energy to provide a national center for collection, evaluation and dissemination of reliability data for advanced reactors. While the system is being developed and continuous data collection at the two U.S. reactor sites (EBR-II and FFTF) is being established, data on advanced reactor components which have been in use at U.S. test loops and experimental reactors have been collected and analyzed. Engineering, operating and event data on sodium valves, pumps, flow meters, rupture discs, heat exchangers and cold traps have been collected from more than a dozen sites. The results of analyses of the data performed to date are presented

Advanced Electrical Materials and Components Development: An Update

Science.gov (United States)

Schwarze, Gene E.

2005-01-01

The primary means to develop advanced electrical components is to develop new and improved materials for magnetic components (transformers, inductors, etc.), capacitors, and semiconductor switches and diodes. This paper will give an update of the Advanced Power Electronics and Components Technology being developed by the NASA Glenn Research Center for use in future Power Management and Distribution subsystems used in space power systems for spacecraft and lunar and planetary surface power. The initial description and status of this technology program was presented two years ago at the First International Energy Conversion Engineering Conference held at Portsmouth, Virginia, August 2003. The present paper will give a brief background of the previous work reported and a summary of research performed the past several years on soft magnetic materials characterization, dielectric materials and capacitor developments, high quality silicon carbide atomically smooth substrates, and SiC static and dynamic device characterization under elevated temperature conditions. The rationale for and the benefits of developing advanced electrical materials and components for the PMAD subsystem and also for the total power system will also be briefly discussed.

System reliability with correlated components: Accuracy of the Equivalent Planes method

NARCIS (Netherlands)

Roscoe, K.; Diermanse, F.; Vrouwenvelder, A.C.W.M.

2015-01-01

Computing system reliability when system components are correlated presents a challenge because it usually requires solving multi-fold integrals numerically, which is generally infeasible due to the computational cost. In Dutch flood defense reliability modeling, an efficient method for computing

System reliability with correlated components : Accuracy of the Equivalent Planes method

NARCIS (Netherlands)

Roscoe, K.; Diermanse, F.; Vrouwenvelder, T.

2015-01-01

Computing system reliability when system components are correlated presents a challenge because it usually requires solving multi-fold integrals numerically, which is generally infeasible due to the computational cost. In Dutch flood defense reliability modeling, an efficient method for computing

Principle of maximum entropy for reliability analysis in the design of machine components

Science.gov (United States)

Zhang, Yimin

2018-03-01

We studied the reliability of machine components with parameters that follow an arbitrary statistical distribution using the principle of maximum entropy (PME). We used PME to select the statistical distribution that best fits the available information. We also established a probability density function (PDF) and a failure probability model for the parameters of mechanical components using the concept of entropy and the PME. We obtained the first four moments of the state function for reliability analysis and design. Furthermore, we attained an estimate of the PDF with the fewest human bias factors using the PME. This function was used to calculate the reliability of the machine components, including a connecting rod, a vehicle half-shaft, a front axle, a rear axle housing, and a leaf spring, which have parameters that typically follow a non-normal distribution. Simulations were conducted for comparison. This study provides a design methodology for the reliability of mechanical components for practical engineering projects.

Influence of the starting materials on performance of high temperature oxide fuel cells devices

Directory of Open Access Journals (Sweden)

Emília Satoshi Miyamaru Seo

2004-03-01

Full Text Available High temperature solid oxide fuel cells (SOFCs offer an environmentally friendly technology to convert gaseous fuels such as hydrogen, natural gas or gasified coal into electricity at high efficiencies. Besides the efficiency, higher than those obtained from the traditional energy conversion systems, a fuel cell provides many other advantages like reliability, modularity, fuel flexibility and very low levels of NOx and SOx emissions. The high operating temperature (950-1000 °C used by the current generation of the solid oxide fuel cells imposes severe constraints on materials selection in order to improve the lifetime of the cell. Besides the good electrical, electrochemical, mechanical and thermal properties, the individual cell components must be stable under the fuel cell operating atmospheres. Each material has to perform not only in its own right but also in conjunction with other system components. For this reason, each cell component must fulfill several different criteria. This paper reviews the materials and the methods used to fabricate the different cell components, such as the cathode, the electrolyte, the anode and the interconnect. Some remarkable results, obtained at IPEN (Nuclear Energy Research Institute in São Paulo, have been presented.

Performance of materials in the component cooling water systems of pressurized water reactors

International Nuclear Information System (INIS)

Lee, B.S.

1993-01-01

The component cooling water (CCW) system provides cooling water to several important loads throughout the plant under all operating conditions. An aging assessment CCW systems in pressurized water reactors (PWRs) was conducted as part of Nuclear Plant Aging Research Program (NPAR) instituted by the US Nuclear Regulatory Commission. This paper presents some of the results on the performances of materials in respect of their application in CCW Systems. All the CCW system failures reported to the Nuclear Plant Reliability Data System (NPRDS) from January 1988 to June 1990 were reviewed; it is concluded that three of the main contributors to CCW system failures are valves, pumps, and heat exchangers. This study identified the modes and causes of failure for these components; most of the causes for the aging-related failures could be related to the performance of materials. Also, in this paper the materials used for these components are reviewed, and there aging mechanisms under CCW system conditions are discussed

Reliability Study of Solder Paste Alloy for the Improvement of Solder Joint at Surface Mount Fine-Pitch Components

Directory of Open Access Journals (Sweden)

Mohd Nizam Ab. Rahman

2014-12-01

Full Text Available The significant increase in metal costs has forced the electronics industry to provide new materials and methods to reduce costs, while maintaining customers’ high-quality expectations. This paper considers the problem of most electronic industries in reducing costly materials, by introducing a solder paste with alloy composition tin 98.3%, silver 0.3%, and copper 0.7%, used for the construction of the surface mount fine-pitch component on a Printing Wiring Board (PWB. The reliability of the solder joint between electronic components and PWB is evaluated through the dynamic characteristic test, thermal shock test, and Taguchi method after the printing process. After experimenting with the dynamic characteristic test and thermal shock test with 20 boards, the solder paste was still able to provide a high-quality solder joint. In particular, the Taguchi method is used to determine the optimal control parameters and noise factors of the Solder Printer (SP machine, that affects solder volume and solder height. The control parameters include table separation distance, squeegee speed, squeegee pressure, and table speed of the SP machine. The result shows that the most significant parameter for the solder volume is squeegee pressure (2.0 mm, and the solder height is the table speed of the SP machine (2.5 mm/s.

Increasing the reliability of the fluid/crystallized difference score from the Kaufman Adolescent and Adult Intelligence Test with reliable component analysis.

Science.gov (United States)

Caruso, J C

2001-06-01

The unreliability of difference scores is a well documented phenomenon in the social sciences and has led researchers and practitioners to interpret differences cautiously, if at all. In the case of the Kaufman Adult and Adolescent Intelligence Test (KAIT), the unreliability of the difference between the Fluid IQ and the Crystallized IQ is due to the high correlation between the two scales. The consequences of the lack of precision with which differences are identified are wide confidence intervals and unpowerful significance tests (i.e., large differences are required to be declared statistically significant). Reliable component analysis (RCA) was performed on the subtests of the KAIT in order to address these problems. RCA is a new data reduction technique that results in uncorrelated component scores with maximum proportions of reliable variance. Results indicate that the scores defined by RCA have discriminant and convergent validity (with respect to the equally weighted scores) and that differences between the scores, derived from a single testing session, were more reliable than differences derived from equal weighting for each age group (11-14 years, 15-34 years, 35-85+ years). This reliability advantage results in narrower confidence intervals around difference scores and smaller differences required for statistical significance.

Parameter estimation of component reliability models in PSA model of Krsko NPP

International Nuclear Information System (INIS)

Jordan Cizelj, R.; Vrbanic, I.

2001-01-01

In the paper, the uncertainty analysis of component reliability models for independent failures is shown. The present approach for parameter estimation of component reliability models in NPP Krsko is presented. Mathematical approaches for different types of uncertainty analyses are introduced and used in accordance with some predisposed requirements. Results of the uncertainty analyses are shown in an example for time-related components. As the most appropriate uncertainty analysis proved the Bayesian estimation with the numerical estimation of a posterior, which can be approximated with some appropriate probability distribution, in this paper with lognormal distribution.(author)

Reliability of Wind Turbine Components-Solder Elements Fatigue Failure

DEFF Research Database (Denmark)

Kostandyan, Erik; Sørensen, John Dalsgaard

2012-01-01

on the temperature mean and temperature range. Constant terms and model errors are estimated. The proposed methods are useful to predict damage values for solder joint in power electrical components. Based on the proposed methods it is described how to find the damage level for a given temperature loading profile....... The proposed methods are discussed for application in reliability assessment of Wind Turbine’s electrical components considering physical, model and measurement uncertainties. For further research it is proposed to evaluate damage criteria for electrical components due to the operational temperature...

Overall Key Performance Indicator to Optimizing Operation of High-Pressure Homogenizers for a Reliable Quantification of Intracellular Components in Pichia pastoris.

Science.gov (United States)

Garcia-Ortega, Xavier; Reyes, Cecilia; Montesinos, José Luis; Valero, Francisco

2015-01-01

The most commonly used cell disruption procedures may present lack of reproducibility, which introduces significant errors in the quantification of intracellular components. In this work, an approach consisting in the definition of an overall key performance indicator (KPI) was implemented for a lab scale high-pressure homogenizer (HPH) in order to determine the disruption settings that allow the reliable quantification of a wide sort of intracellular components. This innovative KPI was based on the combination of three independent reporting indicators: decrease of absorbance, release of total protein, and release of alkaline phosphatase activity. The yeast Pichia pastoris growing on methanol was selected as model microorganism due to it presents an important widening of the cell wall needing more severe methods and operating conditions than Escherichia coli and Saccharomyces cerevisiae. From the outcome of the reporting indicators, the cell disruption efficiency achieved using HPH was about fourfold higher than other lab standard cell disruption methodologies, such bead milling cell permeabilization. This approach was also applied to a pilot plant scale HPH validating the methodology in a scale-up of the disruption process. This innovative non-complex approach developed to evaluate the efficacy of a disruption procedure or equipment can be easily applied to optimize the most common disruption processes, in order to reach not only reliable quantification but also recovery of intracellular components from cell factories of interest.

High reliability megawatt transformer/rectifier

Science.gov (United States)

Zwass, Samuel; Ashe, Harry; Peters, John W.

1991-01-01

The goal of the two phase program is to develop the technology and design and fabricate ultralightweight high reliability DC to DC converters for space power applications. The converters will operate from a 5000 V dc source and deliver 1 MW of power at 100 kV dc. The power weight density goal is 0.1 kg/kW. The cycle to cycle voltage stability goals was + or - 1 percent RMS. The converter is to operate at an ambient temperature of -40 C with 16 minute power pulses and one hour off time. The uniqueness of the design in Phase 1 resided in the dc switching array which operates the converter at 20 kHz using Hollotron plasma switches along with a specially designed low loss, low leakage inductance and a light weight high voltage transformer. This approach reduced considerably the number of components in the converter thereby increasing the system reliability. To achieve an optimum transformer for this application, the design uses four 25 kV secondary windings to produce the 100 kV dc output, thus reducing the transformer leakage inductance, and the ac voltage stresses. A specially designed insulation system improves the high voltage dielectric withstanding ability and reduces the insulation path thickness thereby reducing the component weight. Tradeoff studies and tests conducted on scaled-down model circuits and using representative coil insulation paths have verified the calculated transformer wave shape parameters and the insulation system safety. In Phase 1 of the program a converter design approach was developed and a preliminary transformer design was completed. A fault control circuit was designed and a thermal profile of the converter was also developed.

Thermal fatigue equipment to test joints of materials for high heat flux components

International Nuclear Information System (INIS)

Visca, E.; Libera, S.; Orsini, A.; Riccardi, B.; Sacchetti, M.

2000-01-01

The activity, carried out in the framework of an ITER divertor task, was aimed at defining a suitable method in order to qualify junctions between armour materials and heat sink of plasma-facing components (PFCs) mock-ups. An equipment able to perform thermal fatigue testing by electrical heating and active water-cooling was constructed and a standard for the sample was defined. In this equipment, during operation cycles, two samples are heated by thermal contact up to a relevant temperature value (350 deg. C) and then the water flow is switched on, thus producing fast cooling with time constants and gradients close to the real operating conditions. The equipment works with a test cycle of about 60 s and is suitable for continuous operation. A complete test consists of about 10000 cycles. After the assembling, the equipment and the control software were optimized to obtain a good reliability. Preliminary tests on mock-ups with flat CFC tiles joined to copper heat sink were performed. Finite-elements calculations were carried out in order to estimate the value of the thermal stresses arising close to the joint under the transient conditions that are characteristic of this equipment

Material reliability of Ni alloy electrodeposition for steam generator tube repair

International Nuclear Information System (INIS)

Kim, Dong Jin; Kim, Myong Jin; Kim, Joung Soo; Kim, Hong Pyo

2007-01-01

Due to the occasional occurrences of Stress Corrosion Cracking (SCC) in steam generator tubing (Alloy 600), degraded tubes are removed from service by plugging or are repaired for re-use. Since electrodeposition inside a tube dose not entail parent tube deformation, residual stress in the tube can be minimized. In this work, tube restoration via electrodeposition inside a steam generator tubing was performed after developing the following: an anode probe to be installed inside a tube, a degreasing condition to remove dirt and grease, an activation condition for surface oxide elimination, a tightly adhered strike layer forming condition between the electroforming layer and the Alloy 600 tube, and the condition for an electroforming layer. The reliability of the electrodeposited material, with a variation of material properties, was evaluated as a function of the electrodeposit position in the vertical direction of a tube using the developed anode. It has been noted that the variation of the material properties along the electrodeposit length was acceptable in a process margin. To improve the reliability of a material property, the causes of the variation occurrence were presumed, and an attempt to minimize the variation has been made. A Ni alloy electrodeposition process is suggested as a Primary Water Stress Corrosion Cracking (PWSCC) mitigation method for various components, including steam generator tubes. The Ni alloy electrodeposit formed inside a tube by using the installed assembly shows proper material properties as well as an excellent SCC resistance

Human reliability in non-destructive inspections of nuclear power plant components: modeling and analysis

Energy Technology Data Exchange (ETDEWEB)

Vasconcelos, Vanderley de; Soares, Wellington Antonio; Marques, Raíssa Oliveira; Silva Júnior, Silvério Ferreira da; Raso, Amanda Laureano, E-mail: vasconv@cdtn.br, E-mail: soaresw@cdtn.br, E-mail: raissaomarques@gmail.com, E-mail: silvasf@cdtn.br, E-mail: amandaraso@hotmail.com [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

2017-07-01

Non-destructive inspection (NDI) is one of the key elements in ensuring quality of engineering systems and their safe use. NDI is a very complex task, during which the inspectors have to rely on their sensory, perceptual, cognitive, and motor skills. It requires high vigilance once it is often carried out on large components, over a long period of time, and in hostile environments and restriction of workplace. A successful NDI requires careful planning, choice of appropriate NDI methods and inspection procedures, as well as qualified and trained inspection personnel. A failure of NDI to detect critical defects in safety-related components of nuclear power plants, for instance, may lead to catastrophic consequences for workers, public and environment. Therefore, ensuring that NDI methods are reliable and capable of detecting all critical defects is of utmost importance. Despite increased use of automation in NDI, human inspectors, and thus human factors, still play an important role in NDI reliability. Human reliability is the probability of humans conducting specific tasks with satisfactory performance. Many techniques are suitable for modeling and analyzing human reliability in NDI of nuclear power plant components. Among these can be highlighted Failure Modes and Effects Analysis (FMEA) and THERP (Technique for Human Error Rate Prediction). The application of these techniques is illustrated in an example of qualitative and quantitative studies to improve typical NDI of pipe segments of a core cooling system of a nuclear power plant, through acting on human factors issues. (author)

Human reliability in non-destructive inspections of nuclear power plant components: modeling and analysis

International Nuclear Information System (INIS)

Vasconcelos, Vanderley de; Soares, Wellington Antonio; Marques, Raíssa Oliveira; Silva Júnior, Silvério Ferreira da; Raso, Amanda Laureano

2017-01-01

Non-destructive inspection (NDI) is one of the key elements in ensuring quality of engineering systems and their safe use. NDI is a very complex task, during which the inspectors have to rely on their sensory, perceptual, cognitive, and motor skills. It requires high vigilance once it is often carried out on large components, over a long period of time, and in hostile environments and restriction of workplace. A successful NDI requires careful planning, choice of appropriate NDI methods and inspection procedures, as well as qualified and trained inspection personnel. A failure of NDI to detect critical defects in safety-related components of nuclear power plants, for instance, may lead to catastrophic consequences for workers, public and environment. Therefore, ensuring that NDI methods are reliable and capable of detecting all critical defects is of utmost importance. Despite increased use of automation in NDI, human inspectors, and thus human factors, still play an important role in NDI reliability. Human reliability is the probability of humans conducting specific tasks with satisfactory performance. Many techniques are suitable for modeling and analyzing human reliability in NDI of nuclear power plant components. Among these can be highlighted Failure Modes and Effects Analysis (FMEA) and THERP (Technique for Human Error Rate Prediction). The application of these techniques is illustrated in an example of qualitative and quantitative studies to improve typical NDI of pipe segments of a core cooling system of a nuclear power plant, through acting on human factors issues. (author)

Fatigue Reliability Analysis of Wind Turbine Cast Components

DEFF Research Database (Denmark)

Rafsanjani, Hesam Mirzaei; Sørensen, John Dalsgaard; Fæster, Søren

2017-01-01

.) and to quantify the relevant uncertainties using available fatigue tests. Illustrative results are presented as obtained by statistical analysis of a large set of fatigue data for casted test components typically used for wind turbines. Furthermore, the SN curves (fatigue life curves based on applied stress......The fatigue life of wind turbine cast components, such as the main shaft in a drivetrain, is generally determined by defects from the casting process. These defects may reduce the fatigue life and they are generally distributed randomly in components. The foundries, cutting facilities and test...... facilities can affect the verification of properties by testing. Hence, it is important to have a tool to identify which foundry, cutting and/or test facility produces components which, based on the relevant uncertainties, have the largest expected fatigue life or, alternatively, have the largest reliability...

NDT Reliability - Final Report. Reliability in non-destructive testing (NDT) of the canister components

Energy Technology Data Exchange (ETDEWEB)

Pavlovic, Mato; Takahashi, Kazunori; Mueller, Christina; Boehm, Rainer (BAM, Federal Inst. for Materials Research and Testing, Berlin (Germany)); Ronneteg, Ulf (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden))

2008-12-15

This report describes the methodology of the reliability investigation performed on the ultrasonic phased array NDT system, developed by SKB in collaboration with Posiva, for inspection of the canisters for permanent storage of nuclear spent fuel. The canister is composed of a cast iron insert surrounded by a copper shell. The shell is composed of the tube and the lid/base which are welded to the tube after the fuel has been place, in the tube. The manufacturing process of the canister parts and the welding process are described. Possible defects, which might arise in the canister components during the manufacturing or in the weld during the welding, are identified. The number of real defects in manufactured components have been limited. Therefore the reliability of the NDT system has been determined using a number of test objects with artificial defects. The reliability analysis is based on the signal response analysis. The conventional signal response analysis is adopted and further developed before applied on the modern ultrasonic phased-array NDT system. The concept of multi-parameter a, where the response of the NDT system is dependent on more than just one parameter, is introduced. The weakness of use of the peak signal response in the analysis is demonstrated and integration of the amplitudes in the C-scan is proposed as an alternative. The calculation of the volume POD, when the part is inspected with more configurations, is also presented. The reliability analysis is supported by the ultrasonic simulation based on the point source synthesis method

Thermal Performance and Reliability Characterization of Bonded Interface Materials (BIMs): Preprint

Energy Technology Data Exchange (ETDEWEB)

DeVoto, D.; Paret, P.; Mihalic, M.; Narumanchi, S.; Bar-Cohen, A.; Matin, K.

2014-08-01

Thermal interface materials are an important enabler for low thermal resistance and reliable electronics packaging for a wide array of applications. There is a trend towards bonded interface materials (BIMs) because of their potential for low thermal resistivity (< 1 mm2K/W). However, BIMs induce thermomechanical stresses in the package and can be prone to failures and integrity risks. Deteriorated interfaces can result in high thermal resistance in the package and degradation and/or failure of the electronics. DARPA's Thermal Management Technologies program has addressed this challenge, supporting the development of mechanically-compliant, low resistivity nano-thermal interface (NTI) materials. In this work, we describe the testing procedure and report the results of NREL's thermal performance and reliability characterization of an initial sample of four different NTI-BIMs.

System principles, mathematical models and methods to ensure high reliability of safety systems

Science.gov (United States)

Zaslavskyi, V.

2017-04-01

Modern safety and security systems are composed of a large number of various components designed for detection, localization, tracking, collecting, and processing of information from the systems of monitoring, telemetry, control, etc. They are required to be highly reliable in a view to correctly perform data aggregation, processing and analysis for subsequent decision making support. On design and construction phases of the manufacturing of such systems a various types of components (elements, devices, and subsystems) are considered and used to ensure high reliability of signals detection, noise isolation, and erroneous commands reduction. When generating design solutions for highly reliable systems a number of restrictions and conditions such as types of components and various constrains on resources should be considered. Various types of components perform identical functions; however, they are implemented using diverse principles, approaches and have distinct technical and economic indicators such as cost or power consumption. The systematic use of different component types increases the probability of tasks performing and eliminates the common cause failure. We consider type-variety principle as an engineering principle of system analysis, mathematical models based on this principle, and algorithms for solving optimization problems of highly reliable safety and security systems design. Mathematical models are formalized in a class of two-level discrete optimization problems of large dimension. The proposed approach, mathematical models, algorithms can be used for problem solving of optimal redundancy on the basis of a variety of methods and control devices for fault and defects detection in technical systems, telecommunication networks, and energy systems.

Centralized Reliability Data Organization (CREDO) assessment of critical component unavailability in liquid metal reactors

International Nuclear Information System (INIS)

Koger, K.H.; Haire, M.J.; Humphrys, B.L.; Manneschmidt, J.F.; Setoguchi, K.; Nakai, R.

1988-01-01

The Centralized Reliability Data Organization (CREDO) is the largest repository of liquid metal reactor (LMR) component reliability data in the world. It is jointly sponsored by the US Dept. of Energy (DOE) and the Power Reactor and Nuclear Fuel Development Corporation (PNC) of Japan. The CREDO data base contains information on a population of more than 20,000 components and approximately 1500 event records. A conservative estimation is that the total component operating hours is approaching 2.2 billion hours. The work reported here focuses on the availability information contained in CREDO and the development of availability critical items lists. That is, individual components are ranked in prioritized lists from worst to best performers from an availability standpoint. Availability as used here is an inherent characteristics of the component and is not necessarily related to plant operability. A major observation is that a few components have a much higher unavailability factor than the average. The top fifteen components contribute 93%, 77%, and 87% of the total system unavailability for EBR-II, FFTF, and JOYO respectively. Critical components common to all three sites are mechanical pumps and electromagnetic pumps. Application of resources to these components with the highest unavailability will have the greatest effect on overall availability. All three sites demonstrate that low maintainability (i.e., long repair times), rather than unreliability (i.e., high failure rates), are the main contributors, by about a two-to-one margin, to liquid metal system unavailability

Embedded Sensors and Controls to Improve Component Performance and Reliability Conceptual Design Report

Energy Technology Data Exchange (ETDEWEB)

Kisner, R.; Melin, A.; Burress, T.; Fugate, D.; Holcomb, D.; Wilgen, J.; Miller, J.; Wilson, D.; Silva, P.; Whitlow, L.; Peretz, F.

2012-09-15

The objective of this project is to demonstrate improved reliability and increased performance made possible by deeply embedding instrumentation and controls (I&C) in nuclear power plant (NPP) components and systems. The project is employing a highly instrumented canned rotor, magnetic bearing, fluoride salt pump as its I&C technology demonstration platform. I&C is intimately part of the basic millisecond-by-millisecond functioning of the system; treating I&C as an integral part of the system design is innovative and will allow significant improvement in capabilities and performance. As systems become more complex and greater performance is required, traditional I&C design techniques become inadequate and more advanced I&C needs to be applied. New I&C techniques enable optimal and reliable performance and tolerance of noise and uncertainties in the system rather than merely monitoring quasistable performance. Traditionally, I&C has been incorporated in NPP components after the design is nearly complete; adequate performance was obtained through over-design. By incorporating I&C at the beginning of the design phase, the control system can provide superior performance and reliability and enable designs that are otherwise impossible. This report describes the progress and status of the project and provides a conceptual design overview for the platform to demonstrate the performance and reliability improvements enabled by advanced embedded I&C.

Development of improved processing and evaluation methods for high reliability structural ceramics for advanced heat engine applications Phase II. Final report

Energy Technology Data Exchange (ETDEWEB)

Pujari, V.J.; Tracey, D.M.; Foley, M.R. [and others

1996-02-01

The research program had as goals the development and demonstration of significant improvements in processing methods, process controls, and nondestructive evaluation (NDE) which can be commercially implemented to produce high reliability silicon nitride components for advanced heat engine applications at temperatures to 1370{degrees}C. In Phase I of the program a process was developed that resulted in a silicon nitride - 4 w% yttria HIP`ed material (NCX 5102) that displayed unprecedented strength and reliability. An average tensile strength of 1 GPa and a strength distribution following a 3-parameter Weibull distribution were demonstrated by testing several hundred buttonhead tensile specimens. The Phase II program focused on the development of methodology for colloidal consolidation producing green microstructure which minimizes downstream process problems such as drying, shrinkage, cracking, and part distortion during densification. Furthermore, the program focused on the extension of the process to gas pressure sinterable (GPS) compositions. Excellent results were obtained for the HIP composition processed for minimal density gradients, both with respect to room-temperature strength and high-temperature creep resistance. Complex component fabricability of this material was demonstrated by producing engine-vane prototypes. Strength data for the GPS material (NCX-5400) suggest that it ranks very high relative to other silicon nitride materials in terms of tensile/flexure strength ratio, a measure of volume quality. This high quality was derived from the closed-loop colloidal process employed in the program.

High temperature materials

International Nuclear Information System (INIS)

2003-01-01

The aim of this workshop is to share the needs of high temperature and nuclear fuel materials for future nuclear systems, to take stock of the status of researches in this domain and to propose some cooperation works between the different research organisations. The future nuclear systems are the very high temperature (850 to 1200 deg. C) gas cooled reactors (GCR) and the molten salt reactors (MSR). These systems include not only the reactor but also the fabrication and reprocessing of the spent fuel. This document brings together the transparencies of 13 communications among the 25 given at the workshop: 1) characteristics and needs of future systems: specifications, materials and fuel needs for fast spectrum GCR and very high temperature GCR; 2) high temperature materials out of neutron flux: thermal barriers: materials, resistance, lifetimes; nickel-base metal alloys: status of knowledge, mechanical behaviour, possible applications; corrosion linked with the gas coolant: knowledge and problems to be solved; super-alloys for turbines: alloys for blades and discs; corrosion linked with MSR: knowledge and problems to be solved; 3) materials for reactor core structure: nuclear graphite and carbon; fuel assembly structure materials of the GCR with fast neutron spectrum: status of knowledge and ceramics and cermets needs; silicon carbide as fuel confinement material, study of irradiation induced defects; migration of fission products, I and Cs in SiC; 4) materials for hydrogen production: status of the knowledge and needs for the thermochemical cycle; 5) technologies: GCR components and the associated material needs: compact exchangers, pumps, turbines; MSR components: valves, exchangers, pumps. (J.S.)

Report on the joint meeting of the Division of Development and Technology Plasma/Wall Interaction and High Heat Flux Materials and Components Task Groups

International Nuclear Information System (INIS)

Wilson, K.L.

1985-10-01

This report of the Joint Meeting of the Division of Development and Technology Plasma/Wall Interaction and High Heat Flux Materials and Components Task Groups contains contributing papers in the following areas: Plasma/Materials Interaction Program and Technical Assessment, High Heat Flux Materials and Components Program and Technical Assessment, Pumped Limiters, Ignition Devices, Program Planning Activities, Compact High Power Density Reactor Requirements, Steady State Tokamaks, and Tritium Plasma Experiments. All these areas involve the consideration of High Heat Flux on Materials and the Interaction of the Plasma with the First Wall. Many of the Test Facilities are described as well

EXTENDED WARRANTY STRATEGIES FOR ONLINE SHOPPING SUPPLY CHAIN WITH COMPETING SUPPLIERS CONSIDERING COMPONENT RELIABILITY

Institute of Scientific and Technical Information of China (English)

Xinghong Qin; Qiang Su; Samuel H.Huang

2017-01-01

This article presents the issue of extended warranty and management strategies in a three-echelon competing online shopping supply chain with price-and base warranty period-dependent demand.We employ game theory to develop decision models to explore the interactions between component suppliers and the manufacturer,as well as competition between two component suppliers.Products and extended warranty are sold by an online store,which is the leader in the Stackelberg game.Two scenarios are considered:either the manufacturer offers a prepaid extended warranty to customers or doses not.In each scenario,base warranties are assumed to be bundled with products.Our results show that when the manufacturer's repair costs change in a proper range,providing extended warranty can benefit both the manufacturer and the online store;otherwise,the manufacturer has no incentive to offer the extended warranty.Reducing repair costs,improving component reliability,or shortening the base warranty period allows the manufacturer to realize significantly better value of the extended warranty.High component reliability benefits both the manufacturer and the online store,with the manufacturer reaping more benefit.Extending the length of the base warranty adversely affects profit of the manufacturer and the value of the extended warranty.

Printable Materials for the Realization of High Performance RF Components: Challenges and Opportunities

Directory of Open Access Journals (Sweden)

Eva S. Rosker

2018-01-01

Full Text Available Printing methods such as additive manufacturing (AM and direct writing (DW for radio frequency (RF components including antennas, filters, transmission lines, and interconnects have recently garnered much attention due to the ease of use, efficiency, and low-cost benefits of the AM/DW tools readily available. The quality and performance of these printed components often do not align with their simulated counterparts due to losses associated with the base materials, surface roughness, and print resolution. These drawbacks preclude the community from realizing printed low loss RF components comparable to those fabricated with traditional subtractive manufacturing techniques. This review discusses the challenges facing low loss RF components, which has mostly been material limited by the robustness of the metal and the availability of AM-compatible dielectrics. We summarize the effective printing methods, review ink formulation, and the postprint processing steps necessary for targeted RF properties. We then detail the structure-property relationships critical to obtaining enhanced conductivities necessary for printed RF passive components. Finally, we give examples of demonstrations for various types of printed RF components and provide an outlook on future areas of research that will require multidisciplinary teams from chemists to RF system designers to fully realize the potential for printed RF components.

High purity in steels as a criterion for materials development

International Nuclear Information System (INIS)

Jacobi, H.

1995-01-01

This summarizing report discusses the materials and application prospects for higher purity in steels, which will make possible further advances in materials behaviour and workability. Improvements in purity and homogeneity permit in particular more rational production of thin foils and wire, one-piece shaping of complicated bodywork components and the drawing, wall-ironing and flanging of two-piece beverage cans. Welded designs in plant and mechanical engineering can be fabricated with less effort and less weight. Difficult component geometries and shaping processes can be more easily mastered. Steels with optimized fracture toughness can be exposed to more extreme loads at even lower temperatures: applications worthy of mention include offshore engineering and large-diameter linepipes for use in arctic regions and at great underwater depths. Liquefied-gas transport vessels can be made more resistant to brittle rupture. The bending fatigue strength and service-life of valve-spring and rolling-bearing steels can be significantly increased. High-purity surfaces on piston rods and cylinders guarantee reliability in hydraulic systems, and high-purity calendering rolls permit defect-free embossing of paper surfaces. (orig.)

Interlocking multi-material components made of structured steel sheets and high-pressure die cast aluminium

Science.gov (United States)

Senge, S.; Brachmann, J.; Hirt, G.; Bührig-Polaczek, A.

2017-10-01

Lightweight design is a major driving force of innovation, especially in the automotive industry. Using hybrid components made of two or more different materials is one approach to reduce the vehicles weight and decrease fuel consumption. As a possible way to increase the stiffness of multi-material components, this paper presents a process chain to produce such components made of steel sheets and high-pressure die cast aluminium. Prior to the casting sequence the steel sheets are structured in a modified rolling process which enables continuous interlocking with the aluminium. Two structures manufactured by this rolling process are tested. The first one is a channel like structure and the second one is a channel like structure with undercuts. These undercuts enable the formation of small anchors when the molten aluminium fills them. The correlation between thickness reduction during rolling and the shape of the resulting structure was evaluated for both structures. It can be stated that channels with a depth of up to 0.5 mm and a width of 1 mm could be created. Undercuts with different size depending on the thickness reduction could be realised. Subsequent aluminium high-pressure die casting experiments were performed to determine if the surface structure can be filled gap-free with molten aluminium during the casting sequence and if a gap-free connection can be achieved after contraction of the aluminium. The casting experiments showed that both structures could be filled during the high-pressure die casting. The channel like structure results in a gap between steel and aluminium after contraction of the cast metal whereas the structure with undercuts leads to a good interlocking resulting in a gap-free connection.

Under sodium reliability tests on core components and in-core instrumentation

International Nuclear Information System (INIS)

Ruppert, E.; Stehle, H.; Vinzens, K.

1977-01-01

A sodium test facility for fast breeder core components (AKB), built by INTERATOM at Bensberg, has been operating since 1971 to test fuel dummies and blanket elements as well as absorber elements under simulated normal and extreme reactor conditions. Individual full-scale fuel or blanket elements and arrays of seven elements, modelling a section of the SNR-300 reactor core, have been tested under a wide range of sodium mass flow and isothermal test conditions up to 925K as well as under cyclic changed temperature transients. Besides endurance testing of the core components a special sodium and high-temperature instrumentation is provided to investigate thermohydraulic and vibrational behaviour of the test objects. During all test periods the main subassembly characteristics could be reproduced and the reliability of the instrumentation could be proven. (orig.) [de

Small punch creep test: A promising methodology for high temperature plant components life evaluation

Energy Technology Data Exchange (ETDEWEB)

Tettamanti, S [CISE SpA, Milan (Italy); Crudeli, R [ENEL SpA, Milan (Italy)

1999-12-31

CISE and ENEL are involved for years in a miniaturization creep methodology project to obtain similar non-destructive test with the same standard creep test reliability. The goal can be reached with `Small punch creep test` that collect all the requested characteristics; quasi nondestructive disk specimens extracted both on external or internal side of components, than accurately machined and tested on little and cheap apparatus. CISE has developed complete creep small punch procedure that involved peculiar test facility and correlation`s law comparable with the more diffused isostress methodology for residual life evaluation on ex-serviced high temperature plant components. The aim of this work is to obtain a simple and immediately applicable relationship useful for plant maintenance managing. More added work is need to validate the Small Punch methodology and for relationship calibration on most diffusion high temperature structural materials. First obtained results on a comparative work on ASTM A355 P12 ex-serviced pipe material are presented joint with a description of the Small Punch apparatus realized in CISE. (orig.) 6 refs.

Small punch creep test: A promising methodology for high temperature plant components life evaluation

Energy Technology Data Exchange (ETDEWEB)

Tettamanti, S. [CISE SpA, Milan (Italy); Crudeli, R. [ENEL SpA, Milan (Italy)

1998-12-31

CISE and ENEL are involved for years in a miniaturization creep methodology project to obtain similar non-destructive test with the same standard creep test reliability. The goal can be reached with `Small punch creep test` that collect all the requested characteristics; quasi nondestructive disk specimens extracted both on external or internal side of components, than accurately machined and tested on little and cheap apparatus. CISE has developed complete creep small punch procedure that involved peculiar test facility and correlation`s law comparable with the more diffused isostress methodology for residual life evaluation on ex-serviced high temperature plant components. The aim of this work is to obtain a simple and immediately applicable relationship useful for plant maintenance managing. More added work is need to validate the Small Punch methodology and for relationship calibration on most diffusion high temperature structural materials. First obtained results on a comparative work on ASTM A355 P12 ex-serviced pipe material are presented joint with a description of the Small Punch apparatus realized in CISE. (orig.) 6 refs.

Highly-reliable laser diodes and modules for spaceborne applications

Science.gov (United States)

Deichsel, E.

2017-11-01

Laser applications become more and more interesting in contemporary missions such as earth observations or optical communication in space. One of these applications is light detection and ranging (LIDAR), which comprises huge scientific potential in future missions. The Nd:YAG solid-state laser of such a LIDAR system is optically pumped using 808nm emitting pump sources based on semiconductor laser-diodes in quasi-continuous wave (qcw) operation. Therefore reliable and efficient laser diodes with increased output powers are an important requirement for a spaceborne LIDAR-system. In the past, many tests were performed regarding the performance and life-time of such laser-diodes. There were also studies for spaceborne applications, but a test with long operation times at high powers and statistical relevance is pending. Other applications, such as science packages (e.g. Raman-spectroscopy) on planetary rovers require also reliable high-power light sources. Typically fiber-coupled laser diode modules are used for such applications. Besides high reliability and life-time, designs compatible to the harsh environmental conditions must be taken in account. Mechanical loads, such as shock or strong vibration are expected due to take-off or landing procedures. Many temperature cycles with high change rates and differences must be taken in account due to sun-shadow effects in planetary orbits. Cosmic radiation has strong impact on optical components and must also be taken in account. Last, a hermetic sealing must be considered, since vacuum can have disadvantageous effects on optoelectronics components.

Effect of operating conditions and environment on properties of materials of PWR type nuclear power plant components

International Nuclear Information System (INIS)

Vacek, M.

1987-01-01

Operating reliability and service life of PWR type nuclear power plants are discussed with respect to the material properties of the plant components. The effects of the operating environment on the material properties and the methods of their determination are characterized. Discussed are core materials, such as fuel, its cladding and regulating rod materials, and the materials of pipes, steam generators and condensers. The advances in the production of pressure vessel materials and their degradation during operation are treated in great detail. (Z.M.)

Materials and Designs for High-Efficacy LED Light Engines

Energy Technology Data Exchange (ETDEWEB)

Ibbetson, James [Cree, Inc., Durham, NC (United States); Gresback, Ryan [Cree, Inc., Durham, NC (United States)

2017-09-28

Cree, Inc. conducted a narrow-band downconverter (NBD) materials development and implementation program which will lead to warm-white LED light engines with enhanced efficacy via improved spectral efficiency with respect to the human eye response. New red (600-630nm) NBD materials could result in as much as a 20% improvement in warm-white efficacy at high color quality relative to conventional phosphor-based light sources. Key program innovations included: high quantum yield; narrow peak width; minimized component-level losses due to “cross-talk” and light scattering among red and yellow-green downconverters; and improved reliability to reach parity with conventional phosphors. NBD-enabled downconversion efficiency gains relative to conventional phosphors yielded an end-of-project LED light engine efficacy of >160 lm/W at room temperature and 35 A/cm2, with a correlated color temperature (CCT) of ~3500K and >90 CRI (Color Rending Index). NBD-LED light engines exhibited equivalent luminous flux and color point maintenance at >1,000 hrs. of highly accelerated reliability testing as conventional phosphor LEDs. A demonstration luminaire utilizing an NBD-based LED light engine had a steady-state system efficacy of >150 lm/W at ~3500K and >90 CRI, which exceeded the 2014 DOE R&D Plan luminaire milestone for FY17 of >150 lm/W at just 80 CRI.

Reliability Analysis of Fatigue Failure of Cast Components for Wind Turbines

Directory of Open Access Journals (Sweden)

Hesam Mirzaei Rafsanjani

2015-04-01

Full Text Available Fatigue failure is one of the main failure modes for wind turbine drivetrain components made of cast iron. The wind turbine drivetrain consists of a variety of heavily loaded components, like the main shaft, the main bearings, the gearbox and the generator. The failure of each component will lead to substantial economic losses such as cost of lost energy production and cost of repairs. During the design lifetime, the drivetrain components are exposed to variable loads from winds and waves and other sources of loads that are uncertain and have to be modeled as stochastic variables. The types of loads are different for offshore and onshore wind turbines. Moreover, uncertainties about the fatigue strength play an important role in modeling and assessment of the reliability of the components. In this paper, a generic stochastic model for fatigue failure of cast iron components based on fatigue test data and a limit state equation for fatigue failure based on the SN-curve approach and Miner’s rule is presented. The statistical analysis of the fatigue data is performed using the Maximum Likelihood Method which also gives an estimate of the statistical uncertainties. Finally, illustrative examples are presented with reliability analyses depending on various stochastic models and partial safety factors.

Designing reliability into high-effectiveness industrial gas turbine regenerators

International Nuclear Information System (INIS)

Valentino, S.J.

1979-01-01

The paper addresses the measures necessary to achieve a reliable regenerator design that can withstand higher temperatures (1000-1200 F) and many start and stop cycles - conditions encountered in high-efficiency operation in pipeline applications. The discussion is limited to three major areas: (1) structural analysis of the heat exchanger core - the part of the regenerator that must withstand the higher temperatures and cyclic duty (2) materials data and material selection and (3) a comprehensive test program to demonstrate the reliability of the regenerator. This program includes life-cycle tests, pressure containment in fin panels, core-to-core joint structural test, bellows pressure containment test, sliding pad test, core gas-side passage flow distribution test, and production test. Today's regenerators must have high cyclic life capability, stainless steel construction, and long fault-free service life of 120,000 hr

Material Challenges For Plasma Facing Components in Future Fusion Reactors

International Nuclear Information System (INIS)

Linke, J; Pintsuk, G.; Rödig, M.

2013-01-01

Increasing attention is directed towards thermonuclear fusion as a possible future energy source. Major advantages of this energy conversion technology are the almost inexhaustible resources and the option to produce energy without CO2-emissions. However, in the most advanced field of magnetic plasma confinement a number of technological challenges have to be met. In particular high-temperature resistant and plasma compatible materials have to be developed and qualified which are able to withstand the extreme environments in a commercial thermonuclear power reactor. The plasma facing materials (PFMs) and components (PFCs) in such fusion devices, i.e. the first wall (FW), the limiters and the divertor, are strongly affected by the plasma wall interaction processes and the applied intense thermal loads during plasma operation. On the one hand, these mechanisms have a strong influence on the plasma performance; on the other hand, they have major impact on the lifetime of the plasma facing armour. In present-day and next step devices the resulting thermal steady state heat loads to the first wall remain below 1 MWm-2; the limiters and the divertor are expected to be exposed to power densities being at least one order of magnitude above the FW-level, i.e. up to 20 MWm-2 for next step tokamaks such as ITER or DEMO. These requirements are responsible for high demands on the selection of qualified PFMs and heat sink materials as well as reliable fabrication processes for actively cooled plasma facing components. The technical solutions which are considered today are mainly based on the PFMs beryllium, carbon or tungsten joined to copper alloys or stainless steel heat sinks. In addition to the above mentioned quasi-stationary heat loads, short transient thermal pulses with deposited energy densities up to several tens of MJm-2 are a serious concern for next step tokamak devices. The most frequent events are so-called Edge Localized Modes (type I ELMs) and plasma disruptions

Reliability analysis of nuclear component cooling water system using semi-Markov process model

International Nuclear Information System (INIS)

Veeramany, Arun; Pandey, Mahesh D.

2011-01-01

Research highlights: → Semi-Markov process (SMP) model is used to evaluate system failure probability of the nuclear component cooling water (NCCW) system. → SMP is used because it can solve reliability block diagram with a mixture of redundant repairable and non-repairable components. → The primary objective is to demonstrate that SMP can consider Weibull failure time distribution for components while a Markov model cannot → Result: the variability in component failure time is directly proportional to the NCCW system failure probability. → The result can be utilized as an initiating event probability in probabilistic safety assessment projects. - Abstract: A reliability analysis of nuclear component cooling water (NCCW) system is carried out. Semi-Markov process model is used in the analysis because it has potential to solve a reliability block diagram with a mixture of repairable and non-repairable components. With Markov models it is only possible to assume an exponential profile for component failure times. An advantage of the proposed model is the ability to assume Weibull distribution for the failure time of components. In an attempt to reduce the number of states in the model, it is shown that usage of poly-Weibull distribution arises. The objective of the paper is to determine system failure probability under these assumptions. Monte Carlo simulation is used to validate the model result. This result can be utilized as an initiating event probability in probabilistic safety assessment projects.

An adaptive neuro fuzzy model for estimating the reliability of component-based software systems

Directory of Open Access Journals (Sweden)

Kirti Tyagi

2014-01-01

Full Text Available Although many algorithms and techniques have been developed for estimating the reliability of component-based software systems (CBSSs, much more research is needed. Accurate estimation of the reliability of a CBSS is difficult because it depends on two factors: component reliability and glue code reliability. Moreover, reliability is a real-world phenomenon with many associated real-time problems. Soft computing techniques can help to solve problems whose solutions are uncertain or unpredictable. A number of soft computing approaches for estimating CBSS reliability have been proposed. These techniques learn from the past and capture existing patterns in data. The two basic elements of soft computing are neural networks and fuzzy logic. In this paper, we propose a model for estimating CBSS reliability, known as an adaptive neuro fuzzy inference system (ANFIS, that is based on these two basic elements of soft computing, and we compare its performance with that of a plain FIS (fuzzy inference system for different data sets.

A rapid reliability estimation method for directed acyclic lifeline networks with statistically dependent components

International Nuclear Information System (INIS)

Kang, Won-Hee; Kliese, Alyce

2014-01-01

Lifeline networks, such as transportation, water supply, sewers, telecommunications, and electrical and gas networks, are essential elements for the economic and societal functions of urban areas, but their components are highly susceptible to natural or man-made hazards. In this context, it is essential to provide effective pre-disaster hazard mitigation strategies and prompt post-disaster risk management efforts based on rapid system reliability assessment. This paper proposes a rapid reliability estimation method for node-pair connectivity analysis of lifeline networks especially when the network components are statistically correlated. Recursive procedures are proposed to compound all network nodes until they become a single super node representing the connectivity between the origin and destination nodes. The proposed method is applied to numerical network examples and benchmark interconnected power and water networks in Memphis, Shelby County. The connectivity analysis results show the proposed method's reasonable accuracy and remarkable efficiency as compared to the Monte Carlo simulations

Proceedings of the specialists' meeting on reliability of the ultrasonic inspection of austenitic materials

Energy Technology Data Exchange (ETDEWEB)

NONE

1980-07-01

The contributions of this meeting addressed several topics: the fundamentals of ultrasonic examination of austenitic materials (effect of anisotropy on propagation, improvement of ultrasonic testing to thick bimetallic welds, aspects of the ultrasonic testing of austenitic steel structures, utilization of a Fisher linear discriminant function in intergranular stress corrosion cracking or IGSCC detection, case of coarse grain austenitic welds, efforts of the Argonne National Laboratory), instruments and methods (longitudinal wave ultrasonic inspection, Grass echo suppression technique during the ultrasonic inspection of fuel cladding tubes, inspections of fillet and butt welds, improvement by signal averaging techniques, multiple bearing angle crack detector for cladded pipes examinations, flow-to-grain echo enhancement by split-spectrum processing, ultrasonic imaging techniques, ultrasonic inspection of pipe weldments for IGSCC), industrial practice (ultrasonic testing techniques for fabrication and in-service inspection, experiences in ultrasonic examination of austenitic steel components, experience and practice on nuclear piping in Spain, detection of underclad defects, sizing of cracks perpendicular to stainless overlay), and reliability (survey of ultrasonic testing in austenitic weld material, examination of electron beam welds, factors affecting the reliability of ultrasonic examination, detectability of IGSCC, ultrasonic inspection reliability for primary piping systems)

Proceedings of the specialists' meeting on reliability of the ultrasonic inspection of austenitic materials

International Nuclear Information System (INIS)

1980-01-01

The contributions of this meeting addressed several topics: the fundamentals of ultrasonic examination of austenitic materials (effect of anisotropy on propagation, improvement of ultrasonic testing to thick bimetallic welds, aspects of the ultrasonic testing of austenitic steel structures, utilization of a Fisher linear discriminant function in intergranular stress corrosion cracking or IGSCC detection, case of coarse grain austenitic welds, efforts of the Argonne National Laboratory), instruments and methods (longitudinal wave ultrasonic inspection, Grass echo suppression technique during the ultrasonic inspection of fuel cladding tubes, inspections of fillet and butt welds, improvement by signal averaging techniques, multiple bearing angle crack detector for cladded pipes examinations, flow-to-grain echo enhancement by split-spectrum processing, ultrasonic imaging techniques, ultrasonic inspection of pipe weldments for IGSCC), industrial practice (ultrasonic testing techniques for fabrication and in-service inspection, experiences in ultrasonic examination of austenitic steel components, experience and practice on nuclear piping in Spain, detection of underclad defects, sizing of cracks perpendicular to stainless overlay), and reliability (survey of ultrasonic testing in austenitic weld material, examination of electron beam welds, factors affecting the reliability of ultrasonic examination, detectability of IGSCC, ultrasonic inspection reliability for primary piping systems)

IAEA's experience in compiling a generic component reliability data base

International Nuclear Information System (INIS)

Tomic, B.; Lederman, L.

1988-01-01

Reliability data are an essential part of probabilistic safety assessment. The quality of data can determine the quality of the study as a whole. It is obvious that component failure data originated from the plant being analyzed would be most appropriate. However, in few cases complete reliance on plant experience is possible, mainly because of the rather limited operating experience. Nuclear plants, although of different design, often use fairly similar components, so some of the experience could be combined and transferred from one plant to another. In addition information about component failures is available also from experts with knowledge on component design, manufacturing and operation. That bring us to the importance of assessing generic data. (Generic is meant to be everything that is not plant specific regarding the plant being analyzed). The generic data available in the open literature, can be divided in three broad categories. The first one includes data base used in previous analysis. These can be plant specific or updated from generic with plant specific information (latter case deserve special attention). The second one is based on compilation of plants' operating experience usually based on some kind of event reporting system. The third category includes data sources based on expert opinions (single or aggregate) or combination of expert opinions and other nuclear and non-nuclear experience. This paper reflects insights gained in compiling data from generic data sources and highlights advantages and pitfalls of using generic component reliability data in PSAs

Reliability, availability, and quality assurance considerations for fusion components

International Nuclear Information System (INIS)

Buende, R.

1995-01-01

The complexity of magnetic confinement machines has been a matter of concern in developing fusion power plants as electricity generating stations because it might reduce plant availability. A comprehensive reliability and availability (R and A) programme to determine the availability of a next step fusion machine was performed during definition and conceptual design of the Next European Torus. In addition to giving an overview of the expected contributions to unavailability of the various components, this activity identified the basic approach to be taken to specify and to achieve necessary improvements. This paper, after giving some basic definitions, describes the essentials of the R and A programme, its results, and the guidelines derived for further work towards a sufficiently reliable fusion plant. These guidelines refer to improvement of the reliability database and the quality assurance to be performed at the design stage of a next step machine. (orig.)

Solder joint technology materials, properties, and reliability

CERN Document Server

Tu, King-Ning

2007-01-01

Solder joints are ubiquitous in electronic consumer products. The European Union has a directive to ban the use of Pb-based solders in these products on July 1st, 2006. There is an urgent need for an increase in the research and development of Pb-free solders in electronic manufacturing. For example, spontaneous Sn whisker growth and electromigration induced failure in solder joints are serious issues. These reliability issues are quite complicated due to the combined effect of electrical, mechanical, chemical, and thermal forces on solder joints. To improve solder joint reliability, the science of solder joint behavior under various driving forces must be understood. In this book, the advanced materials reliability issues related to copper-tin reaction and electromigration in solder joints are emphasized and methods to prevent these reliability problems are discussed.

Toward a virtual platform for materials processing

Science.gov (United States)

Schmitz, G. J.; Prahl, U.

2009-05-01

Any production is based on materials eventually becoming components of a final product. Material properties being determined by the microstructure of the material thus are of utmost importance both for productivity and reliability of processing during production and for application and reliability of the product components. A sound prediction of materials properties therefore is highly important. Such a prediction requires tracking of microstructure and properties evolution along the entire component life cycle starting from a homogeneous, isotropic and stress-free melt and eventually ending in failure under operational load. This article will outline ongoing activities at the RWTH Aachen University aiming at establishing a virtual platform for materials processing comprising a virtual, integrative numerical description of processes and of the microstructure evolution along the entire production chain and even extending further toward microstructure and properties evolution under operational conditions.

Between-Day Reliability of Pre-Participation Screening Components in Pre-Professional Ballet and Contemporary Dancers.

Science.gov (United States)

Kenny, Sarah J; Palacios-Derflingher, Luz; Owoeye, Oluwatoyosi B A; Whittaker, Jackie L; Emery, Carolyn A

2018-03-15

Critical appraisal of research investigating risk factors for musculoskeletal injury in dancers suggests high quality reliability studies are lacking. The purpose of this study was to determine between-day reliability of pre-participation screening (PPS) components in pre-professional ballet and contemporary dancers. Thirty-eight dancers (35 female, 3 male; median age; 18 years; range: 11 to 30 years) participated. Screening components (Athletic Coping Skills Inventory-28, body mass index, percent total body fat, total bone mineral density, Foot Posture Index-6, hip and ankle range of motion, three lumbopelvic control tasks, unipedal dynamic balance, and the Y-Balance Test) were conducted one week apart. Intra-class correlation coefficients (ICCs: 95% confidence intervals), standard error of measurement, minimal detectable change (MDC), Bland-Altman methods of agreement [95% limits of agreement (LOA)], Cohen's kappa coefficients, standard error, and percent agreements were calculated. Depending on the screening component, ICC estimates ranged from 0.51 to 0.98, kappa coefficients varied between -0.09 and 0.47, and percent agreement spanned 71% to 95%. Wide 95% LOA were demonstrated by Foot Posture Index-6 (right: -6.06, 7.31), passive hip external rotation (right: -9.89, 16.54), and passive supine turnout (left: -15.36, 17.58). The PPS components examined demonstrated moderate to excellent relative reliability with mean between-day differences less than MDC, or sufficient percent agreement, across all assessments. However, due to wide 95% limits of agreement, the Foot Posture Index-6 and passive hip range of motion are not recommended for screening injury risk in pre-professional dancers.

Applying the High Reliability Health Care Maturity Model to Assess Hospital Performance: A VA Case Study.

Science.gov (United States)

Sullivan, Jennifer L; Rivard, Peter E; Shin, Marlena H; Rosen, Amy K

2016-09-01

The lack of a tool for categorizing and differentiating hospitals according to their high reliability organization (HRO)-related characteristics has hindered progress toward implementing and sustaining evidence-based HRO practices. Hospitals would benefit both from an understanding of the organizational characteristics that support HRO practices and from knowledge about the steps necessary to achieve HRO status to reduce the risk of harm and improve outcomes. The High Reliability Health Care Maturity (HRHCM) model, a model for health care organizations' achievement of high reliability with zero patient harm, incorporates three major domains critical for promoting HROs-Leadership, Safety Culture, and Robust Process Improvement ®. A study was conducted to examine the content validity of the HRHCM model and evaluate whether it can differentiate hospitals' maturity levels for each of the model's components. Staff perceptions of patient safety at six US Department of Veterans Affairs (VA) hospitals were examined to determine whether all 14 HRHCM components were present and to characterize each hospital's level of organizational maturity. Twelve of the 14 components from the HRHCM model were detected; two additional characteristics emerged that are present in the HRO literature but not represented in the model-teamwork culture and system-focused tools for learning and improvement. Each hospital's level of organizational maturity could be characterized for 9 of the 14 components. The findings suggest the HRHCM model has good content validity and that there is differentiation between hospitals on model components. Additional research is needed to understand how these components can be used to build the infrastructure necessary for reaching high reliability.

Current trends in degradation assesment on metallic materials of industrial components

International Nuclear Information System (INIS)

Herrera Palma, Victoria

2007-01-01

To needs to assess objectively a structural integrity analysis in nuclear and termal power-, oil- and chemical- industry system, represents a large challenge for engineer and researches related to Materials Science, equipment manufactures or users. These systems share many of their problems with regards to aging mechanism of components metallic materials, high replacement costs and increasing requirements on efficiency and safety. This paper makes an attempt to give an overview of the current trends on material damage and residual life assessment for installation of power-, oil- and chemical industry. Some of the currently existing ideas on components inspection, as an activity for damage detection are shown. A summary on mechanism of material damage and experimental techniques for their characterization is also presented. Finally, some analytical methods with wide appliance in materials damage evaluation and residual life assesment of components are described

Assessing the suitability of written stroke materials: an evaluation of the interrater reliability of the suitability assessment of materials (SAM) checklist.

Science.gov (United States)

Hoffmann, Tammy; Ladner, Yvette

2012-01-01

Written materials are frequently used to provide education to stroke patients and their carers. However, poor quality materials are a barrier to effective information provision. A quick and reliable method of evaluating material quality is needed. This study evaluated the interrater reliability of the Suitability Assessment of Materials (SAM) checklist in a sample of written stroke education materials. Two independent raters evaluated the materials (n = 25) using the SAM, and ratings were analyzed to reveal total percentage agreements and weighted kappa values for individual items and overall SAM rating. The majority of the individual SAM items had high interrater reliability, with 17 of the 22 items achieving substantial, almost perfect, or perfect weighted kappa value scores. The overall SAM rating achieved a weighted kappa value of 0.60, with a percentage total agreement of 96%. Health care professionals should evaluate the content and design characteristics of written education materials before using them with patients. A tool such as the SAM checklist can be used; however, raters should exercise caution when interpreting results from items with more subjective scoring criteria. Refinements to the scoring criteria for these items are recommended. The value of the SAM is that it can be used to identify specific elements that should be modified before education materials are provided to patients.

Seismic proving tests on the reliability for large components and equipment of nuclear power plants

International Nuclear Information System (INIS)

Ohno, Tokue; Tanaka, Nagatoshi

1988-01-01

Since Japan has destructive earthquakes frequently, the structural reliability for large components and equipment of nuclear power plants are rigorously required. They are designed using sophisticated seismic analyses and have not yet encountered a destructive earthquake. When nuclear power plants are planned, it is very important that the general public understand the structural reliability during and after an earthquake. Seismic Proving Tests have been planned by Ministry of International Trade and Industry (Miti) to comply with public requirement in Japan. A large-scale high-performance vibration table was constructed at Tasted Engineering Laboratory of Nuclear Power Engineering Test Center (NU PEC), in order to prove the structural reliability by vibrating the test model (of full scale or close to the actual size) in the condition of a destructive earthquake. As for the test models, the following four items were selected out of large components and equipment important to the safety: Reactor Containment Vessel; Primary Coolant Loop or Primary Loop Recirculation System; Reactor Pressure Vessel; and Reactor Core Internals. Here is described a brief of the vibration table, the test method and the results of the tests on PWR Reactor Containment Vessel and BWR Primary Loop Recirculation System (author)

Development of high-reliability control system for nuclear power plants

International Nuclear Information System (INIS)

Asami, K.; Yanai, K.; Hirose, H.; Ito, T.

1983-01-01

In Japan, many nuclear power generating plants are in operation and under construction. There is a general awareness of the problems in connection with nuclear power generation and strong emphasis is put on achieving highly reliable operation of nuclear power plants. Hitachi has developed a new high-reliability control system. NURECS-3000 (NUclear Power Plant High-REliability Control System), which is applied to the main control systems, such as the reactor feedwater control system, the reactor recirculation control system and the main turbine control system. The NURECS-3000 system was designed taking into account the fact that there will be failures, but the aim is for the system to continue to function correctly; it is therefore a fault-tolerant system. It has redundant components which can be completely isolated from each other in order to prevent fault propagation. The system has a hierarchical configuration, with a main controller, consisting of a triplex microcomputer system, and sub-loop controllers. Special care was taken to ensure the independence of these subsystems. Since most of the redundant system failures are caused by common-mode failures and the reliability of redundant systems depends on the reliability of the common-mode parts, the aim was to minimize these parts. (author)

Reliability Assessment Of Wind Turbines

DEFF Research Database (Denmark)

Sørensen, John Dalsgaard

2014-01-01

Reduction of cost of energy for wind turbines are very important in order to make wind energy competitive compared to other energy sources. Therefore the turbine components should be designed to have sufficient reliability but also not be too costly (and safe). This paper presents models...... for uncertainty modeling and reliability assessment of especially the structural components such as tower, blades, substructure and foundation. But since the function of a wind turbine is highly dependent on many electrical and mechanical components as well as a control system also reliability aspects...... of these components are discussed and it is described how there reliability influences the reliability of the structural components. Two illustrative examples are presented considering uncertainty modeling, reliability assessment and calibration of partial safety factors for structural wind turbine components exposed...

Nuclear Computerized Library for Assessing Reactor Reliability (NUCLARR): Data manual. Part 3: Hardware component failure data; Volume 5, Revision 4

International Nuclear Information System (INIS)

Reece, W.J.; Gilbert, B.G.; Richards, R.E.

1994-09-01

This data manual contains a hard copy of the information in the Nuclear Computerized Library for Assessing Reactor Reliability (NUCLARR) Version 3.5 database, which is sponsored by the US Nuclear Regulatory Commission. NUCLARR was designed as a tool for risk analysis. Many of the nuclear reactors in the US and several outside the US are represented in the NUCLARR database. NUCLARR includes both human error probability estimates for workers at the plants and hardware failure data for nuclear reactor equipment. Aggregations of these data yield valuable reliability estimates for probabilistic risk assessments and human reliability analyses. The data manual is organized to permit manual searches of the information if the computerized version is not available. Originally, the manual was published in three parts. In this revision the introductory material located in the original Part 1 has been incorporated into the text of Parts 2 and 3. The user can now find introductory material either in the original Part 1, or in Parts 2 and 3 as revised. Part 2 contains the human error probability data, and Part 3, the hardware component reliability data

Reactor pressure boundary materials

International Nuclear Information System (INIS)

Hong, Jun Hwa; Chi, S. H.; Lee, B. S.

2002-04-01

With a long-term operation of nuclear power plants, the component materials are degraded under severe reactor conditions such as neutron irradiation, high temperature, high pressure and corrosive environment. It is necessary to establish the reliable and practical technologies for improving and developing the component materials and for evaluating the mechanical properties. Especially, it is very important to investigate the technologies for reactor pressure boundary materials such as reactor vessel and pipings in accordance with their critical roles. Therefore, this study was focused on developing and advancing the microstructural/micro-mechanical evaluation technologies, and on evaluating the neutron irradiation characteristics and radiation effects analysis technology of the reactor pressure boundary materials, and also on establishing a basis of nuclear material property database

Screening of High Temperature Organic Materials for Future Stirling Convertors

Science.gov (United States)

Shin, Euy-sik E.; Scheiman, Daniel A.

2017-01-01

Along with major advancement of Stirling-based convertors, high temperature organics are needed to develop future higher temperature convertors for much improved efficiencies as well as to improve the margin of reliability for the current SOA (State-of-the-Art) convertors. The higher temperature capabilities would improve robustness of the convertors and also allow them to be used in additional missions, particularly ones that require a Venus flyby for a gravity assist. Various organic materials have been employed as essential components in the convertor for their unique properties and functions such as bonding, potting, sealing, thread locking, insulation, and lubrication. The Stirling convertor radioisotope generators have been developed for potential future space applications including Lunar/Mars surface power or a variety of spacecraft and vehicles, especially with a long mission cycle, sometimes up to 17 years, such as deep space exploration. Thus, performance, durability, and reliability of the organics should be critically evaluated in terms of every possible material structure-process-service environment relations based on the potential mission specifications. The initial efforts in screening the high temperature candidates focused on the most susceptible organics, such as adhesive, potting compound, O-ring, shrink tubing, and thread locker materials in conjunction with commercially available materials. More systematic and practical test methodologies that were developed and optimized based on the extensive organic evaluations and validations performed for various Stirling convertor types were employed to determine thermal stability, outgassing, and material compatibility of the selected organic candidates against their functional requirements. Processing and fabrication conditions and procedures were also optimized. This report presents results of the three-step candidate evaluation processes, their application limitations, and the final selection

ARCHER Project: Progress on Material and component activities for the Advanced High Temperature Reactor

International Nuclear Information System (INIS)

Buckthorpe, D.E.

2014-01-01

The ARCHER (Advanced High-Temperature Reactors for Cogeneration of Heat and Electricity R&D) integrated project is a four year project which was started in 2011 as part of the European Commission 7th Framework Programme (FP7) to perform High Temperature Reactor technology R&D in support of reactor demonstration. The project consortium encompasses conventional and Nuclear Industry, Utilities, Technical Support Organizations, Research & Development Organizations and Academia. The activities involved contribute to the Generation IV (GIF) International Forum and collaborate with related projects in the US, China, Japan, and the Republic of Korea in cooperation with IAEA and ISTC. This paper addresses the progress of the work on ARCHER materials and component activities since the start of the project and underlines some of the main conclusions reached. (author)

Reliability prediction of large fuel cell stack based on structure stress analysis

Science.gov (United States)

Liu, L. F.; Liu, B.; Wu, C. W.

2017-09-01

The aim of this paper is to improve the reliability of Proton Electrolyte Membrane Fuel Cell (PEMFC) stack by designing the clamping force and the thickness difference between the membrane electrode assembly (MEA) and the gasket. The stack reliability is directly determined by the component reliability, which is affected by the material property and contact stress. The component contact stress is a random variable because it is usually affected by many uncertain factors in the production and clamping process. We have investigated the influences of parameter variation coefficient on the probability distribution of contact stress using the equivalent stiffness model and the first-order second moment method. The optimal contact stress to make the component stay in the highest level reliability is obtained by the stress-strength interference model. To obtain the optimal contact stress between the contact components, the optimal thickness of the component and the stack clamping force are optimally designed. Finally, a detailed description is given how to design the MEA and gasket dimensions to obtain the highest stack reliability. This work can provide a valuable guidance in the design of stack structure for a high reliability of fuel cell stack.

Brazing and machining of carbon based materials for plasma facing components

International Nuclear Information System (INIS)

Brossa, M.; Guerreschi, U.; Rossi, M.

1994-01-01

Carbon based materials in the recent years have often been considered and used as armour material in plasma facing components for several fusion devices, because of their low Z and good high temperature characteristics that are compatible with the operation of nuclear reactors. These materials are often connected (mechanically or by brazing) to metals, that allow the support and the cooling functions (heat sink materials). In the following the experience of Ansaldo Ricerche about the study and the manufacturing of plasma facing components and mockups is described with reference to the influence of the carbon materials in performing brazing junction with metals. It is interesting to observe how the different characteristics of the carbon materials influence the brazing process. ((orig.))

High temperature testing - a contribution to alloy development, alloy qualification and simulation of component Loading

International Nuclear Information System (INIS)

Scholz, A.; Schwienheer, M.; Mueller, F.; Linn, S.; Schein, M.; Walther, C.; Berger, C.

2007-01-01

In parallel to continued developments of steam and gas turbines as well as traffic engineering machines on the one hand, and marginal conditions like low specific fuel consumption and sufficient environment-friendliness on the other hand, the aim of improving the degree of efficiency by augmenting process parameters such as temperature and pressure is being followed. These efforts impact especially components of thermic machines and facilities subject to high thermal and mechanic exposure. Still largely unexplored is the interaction between microstructure characteristics determined through chemical composition, production processes and heat treatment, changes in the microstructure due to multiaxial load and the time-dependent deformation and stability resulting hereof. With regard to this background, improved methods of material properties determination, their modelling and transfer on the component enable to optimize wall thicknesses and degrees of efficiency. In the course of evaluation of static and cyclic material properties carried out also on faulty specimens, uncertainties occur which can originate from the testing process and analysis, as well as being influenced by the material itself and its process of production. Altogether, the demand for reliable determination of material properties and methods of scatterband treatment and their mathematical-statistical evaluation is in business. For simulation, consistent material datasets that describe the complex interaction between temperature, period of exposure and type of exposure are needed. Summarizing, the tasks dealt with qualify the entire process from production to the operational behaviour of components. (Abstract Copyright [2007], Wiley Periodicals, Inc.) [de

Metallic materials for heat exchanger components and highly stressed internal of HTR reactors for nuclear process heat generation

International Nuclear Information System (INIS)

1982-01-01

The programme was aimed at the development and improvement of materials for the high-temperature heat exchanger components of a process steam HTR. The materials must have high resistance to corrosion, i.e. carburisation and internal oxidation, and high long-term toughness over a wide range of temperatures. They must also meet the requirements set in the nuclear licensing procedure, i.e. resistance to cyclic stress and irradiation, non-destructive testing, etc. Initially, it was only intended to improve and qualify commercial alloys. Later on an alloy development programme was initiated in which new, non-commercial alloys were produced and modified for use in a nuclear process heat facility. Separate abstracts were prepared for 19 pays of this volume. (orig./IHOE) [de

High pressure, high current, low inductance, high reliability sealed terminals

Science.gov (United States)

Hsu, John S [Oak Ridge, TN; McKeever, John W [Oak Ridge, TN

2010-03-23

The invention is a terminal assembly having a casing with at least one delivery tapered-cone conductor and at least one return tapered-cone conductor routed there-through. The delivery and return tapered-cone conductors are electrically isolated from each other and positioned in the annuluses of ordered concentric cones at an off-normal angle. The tapered cone conductor service can be AC phase conductors and DC link conductors. The center core has at least one service conduit of gate signal leads, diagnostic signal wires, and refrigerant tubing routed there-through. A seal material is in direct contact with the casing inner surface, the tapered-cone conductors, and the service conduits thereby hermetically filling the interstitial space in the casing interior core and center core. The assembly provides simultaneous high-current, high-pressure, low-inductance, and high-reliability service.

Materials for heat flux components of the first wall in fusion reactors

International Nuclear Information System (INIS)

Hoven, H.; Koizlik, K.; Linke, J.; Nickel, H.; Wallura, E.

1985-08-01

Materials of the First Wall in near-fusion plasma machines are subjected to a complex load system resulting from the plasma-wall interaction. The materials for their part also influence the plasma. Suitable materials must be available in order to ensure that the wall components achieve a sufficiently long dwell time and that their effects on the plasma remain small and controllable. The present report discusses relations between the plasma-wall interaction, the reactions of the materials and testing and examination methods for specific problems in developing and selecting suitable materials for highly stressed components on the First Wall of fusion reactors. (orig.)

Reliability studies of a high-power proton accelerator for accelerator-driven system applications for nuclear waste transmutation

Energy Technology Data Exchange (ETDEWEB)

Burgazzi, Luciano [ENEA-Centro Ricerche ' Ezio Clementel' , Advanced Physics Technology Division, Via Martiri di Monte Sole, 4, 40129 Bologna (Italy)]. E-mail: burgazzi@bologna.enea.it; Pierini, Paolo [INFN-Sezione di Milano, Laboratorio Acceleratori e Superconduttivita Applicata, Via Fratelli Cervi 201, I-20090 Segrate (MI) (Italy)

2007-04-15

The main effort of the present study is to analyze the availability and reliability of a high-performance linac (linear accelerator) conceived for Accelerator-Driven Systems (ADS) purpose and to suggest recommendations, in order both to meet the high operability goals and to satisfy the safety requirements dictated by the reactor system. Reliability Block Diagrams (RBD) approach has been considered for system modelling, according to the present level of definition of the design: component failure modes are assessed in terms of Mean Time Between Failure (MTBF) and Mean Time To Repair (MTTR), reliability and availability figures are derived, applying the current reliability algorithms. The lack of a well-established component database has been pointed out as the main issue related to the accelerator reliability assessment. The results, affected by the conservative character of the study, show a high margin for the improvement in terms of accelerator reliability and availability figures prediction. The paper outlines the viable path towards the accelerator reliability and availability enhancement process and delineates the most proper strategies. The improvement in the reliability characteristics along this path is shown as well.

Reliability studies of a high-power proton accelerator for accelerator-driven system applications for nuclear waste transmutation

International Nuclear Information System (INIS)

Burgazzi, Luciano; Pierini, Paolo

2007-01-01

The main effort of the present study is to analyze the availability and reliability of a high-performance linac (linear accelerator) conceived for Accelerator-Driven Systems (ADS) purpose and to suggest recommendations, in order both to meet the high operability goals and to satisfy the safety requirements dictated by the reactor system. Reliability Block Diagrams (RBD) approach has been considered for system modelling, according to the present level of definition of the design: component failure modes are assessed in terms of Mean Time Between Failure (MTBF) and Mean Time To Repair (MTTR), reliability and availability figures are derived, applying the current reliability algorithms. The lack of a well-established component database has been pointed out as the main issue related to the accelerator reliability assessment. The results, affected by the conservative character of the study, show a high margin for the improvement in terms of accelerator reliability and availability figures prediction. The paper outlines the viable path towards the accelerator reliability and availability enhancement process and delineates the most proper strategies. The improvement in the reliability characteristics along this path is shown as well

Nonparametric predictive inference for reliability of a k-out-of-m:G system with multiple component types

International Nuclear Information System (INIS)

Aboalkhair, Ahmad M.; Coolen, Frank P.A.; MacPhee, Iain M.

2014-01-01

Nonparametric predictive inference for system reliability has recently been presented, with specific focus on k-out-of-m:G systems. The reliability of systems is quantified by lower and upper probabilities of system functioning, given binary test results on components, taking uncertainty about component functioning and indeterminacy due to limited test information explicitly into account. Thus far, systems considered were series configurations of subsystems, with each subsystem i a k i -out-of-m i :G system which consisted of only one type of components. Key results are briefly summarized in this paper, and as an important generalization new results are presented for a single k-out-of-m:G system consisting of components of multiple types. The important aspects of redundancy and diversity for such systems are discussed. - Highlights: • New results on nonparametric predictive inference for system reliability. • Prediction of system reliability based on test data for components. • New insights on system redundancy optimization and diversity. • Components that appear inferior in tests may be included to enhance redundancy

Modeling high-Power Accelerators Reliability-SNS LINAC (SNS-ORNL); MAX LINAC (MYRRHA)

International Nuclear Information System (INIS)

Pitigoi, A. E.; Fernandez Ramos, P.

2013-01-01

Improving reliability has recently become a very important objective in the field of particle accelerators. The particle accelerators in operation are constantly undergoing modifications, and improvements are implemented using new technologies, more reliable components or redundant schemes (to obtain more reliability, strength, more power, etc.) A reliability model of SNS (Spallation Neutron Source) LINAC has been developed within MAX project and analysis of the accelerator systems reliability has been performed within the MAX project, using the Risk Spectrum reliability analysis software. The analysis results have been evaluated by comparison with the SNS operational data. Results and conclusions are presented in this paper, oriented to identify design weaknesses and provide recommendations for improving reliability of MYRRHA linear accelerator. The SNS reliability model developed for the MAX preliminary design phase indicates possible avenues for further investigation that could be needed to improve the reliability of the high-power accelerators, in view of the future reliability targets of ADS accelerators.

EU Development of High Heat Flux Components

International Nuclear Information System (INIS)

Linke, J.; Lorenzetto, P.; Majerus, P.; Merola, M.; Pitzer, D.; Roedig, M.

2005-01-01

The development of plasma facing components for next step fusion devices in Europe is strongly focused to ITER. Here a wide spectrum of different design options for the divertor target and the first wall have been investigated with tungsten, CFC, and beryllium armor. Electron beam simulation experiments have been used to determine the performance of high heat flux components under ITER specific thermal loads. Beside thermal fatigue loads with power density levels up to 20 MWm -2 , off-normal events are a serious concern for the lifetime of plasma facing components. These phenomena are expected to occur on a time scale of a few milliseconds (plasma disruptions) or several hundred milliseconds (vertical displacement events) and have been identified as a major source for the production of neutron activated metallic or tritium enriched carbon dust which is of serious importance from a safety point of view.The irradiation induced material degradation is another critical concern for future D-T-burning fusion devices. In ITER the integrated neutron fluence to the first wall and the divertor armour will remain in the order of 1 dpa and 0.7 dpa, respectively. This value is low compared to future commercial fusion reactors; nevertheless, a nonnegligible degradation of the materials has been detected, both for mechanical and thermal properties, in particular for the thermal conductivity of carbon based materials. Beside the degradation of individual material properties, the high heat flux performance of actively cooled plasma facing components has been investigated under ITER specific thermal and neutron loads

Mechanical thermal and electric measurements on materials and components of the main coils of the Milan superconducting cyclotron

International Nuclear Information System (INIS)

Acerbi, E.; Rossi, L.

1988-01-01

The coils of the Milan Superconducting Cyclotron are the largest superconducting devices built up to now in Italy and constitute the first superconducting magnet for accelerator in Europe. Because of the large stored energy (more than 40 MJ), of the high stresses and of of the need of reliability, a lot of measurements were carried out as well on materials used for the coils, both on superconducting cable and structural materials, as on the main components of the coils and on two double pancakes prototypes (wound with full copper cable). In this paper the results on these measurements are reported and the results of tests on the prototypes are discussed. The aim is to provide an easy source of data for superconducting coils useful to verify calculations or to improve the performances

Material testing facilities and programs for plasma-facing component testing

Science.gov (United States)

Linsmeier, Ch.; Unterberg, B.; Coenen, J. W.; Doerner, R. P.; Greuner, H.; Kreter, A.; Linke, J.; Maier, H.

2017-09-01

Component development for operation in a large-scale fusion device requires thorough testing and qualification for the intended operational conditions. In particular environments are necessary which are comparable to the real operation conditions, allowing at the same time for in situ/in vacuo diagnostics and flexible operation, even beyond design limits during the testing. Various electron and neutral particle devices provide the capabilities for high heat load tests, suited for material samples and components from lab-scale dimensions up to full-size parts, containing toxic materials like beryllium, and being activated by neutron irradiation. To simulate the conditions specific to a fusion plasma both at the first wall and in the divertor of fusion devices, linear plasma devices allow for a test of erosion and hydrogen isotope recycling behavior under well-defined and controlled conditions. Finally, the complex conditions in a fusion device (including the effects caused by magnetic fields) are exploited for component and material tests by exposing test mock-ups or material samples to a fusion plasma by manipulator systems. They allow for easy exchange of test pieces in a tokamak or stellarator device, without opening the vessel. Such a chain of test devices and qualification procedures is required for the development of plasma-facing components which then can be successfully operated in future fusion power devices. The various available as well as newly planned devices and test stands, together with their specific capabilities, are presented in this manuscript. Results from experimental programs on test facilities illustrate their significance for the qualification of plasma-facing materials and components. An extended set of references provides access to the current status of material and component testing capabilities in the international fusion programs.

Magnetic fusion energy plasma interactive and high heat flux components. Volume II. Technical assessment of the critical issues and problem areas in high heat flux materials and component development

International Nuclear Information System (INIS)

Abdou, M.A.; Boyd, R.D.; Easor, J.R.

1984-06-01

A technical assessment of the critical issues and problem areas for high heat flux materials and components (HHFMC) in magnetic fusion devices shows these problems to be of critical importance for the successful operation of near-term fusion experiments and for the feasibility and attractiveness of long-term fusion reactors. A number of subgroups were formed to assess the critical HHFMC issues along the following major lines: (1) source conditions, (2) systems integration, (3) materials and processes, (4) thermal hydraulics, (5) thermomechanical response, (6) electromagnetic response, (7) instrumentation and control, and (8) test facilities. The details of the technical assessment are presented in eight chapters. The primary technical issues and needs for each area are highlighted

Magnetic fusion energy plasma interactive and high heat flux components. Volume II. Technical assessment of the critical issues and problem areas in high heat flux materials and component development

Energy Technology Data Exchange (ETDEWEB)

Abdou, M.A.; Boyd, R.D.; Easor, J.R.; Gauster, W.B.; Gordon, J.D.; Mattas, R.F.; Morgan, G.D.; Ulrickson, M.A,; Watson, R.D.; Wolfer, W.G,

1984-06-01

A technical assessment of the critical issues and problem areas for high heat flux materials and components (HHFMC) in magnetic fusion devices shows these problems to be of critical importance for the successful operation of near-term fusion experiments and for the feasibility and attractiveness of long-term fusion reactors. A number of subgroups were formed to assess the critical HHFMC issues along the following major lines: (1) source conditions, (2) systems integration, (3) materials and processes, (4) thermal hydraulics, (5) thermomechanical response, (6) electromagnetic response, (7) instrumentation and control, and (8) test facilities. The details of the technical assessment are presented in eight chapters. The primary technical issues and needs for each area are highlighted.

Reliability on the move: safety and reliability in transportation

International Nuclear Information System (INIS)

Guy, G.B.

1989-01-01

The development of transportation has been a significant factor in the development of civilisation as a whole. Our technical ability to move people and goods now seems virtually limitless when one considers for example the achievements of the various space programmes. Yet our current achievements rely heavily on high standards of safety and reliability from equipment and the human component of transportation systems. Recent failures have highlighted our dependence on equipment and human reliability. This book represents the proceedings of the 1989 Safety and Reliability Society symposium held at Bath on 11-12 October 1989. The structure of the book follows the structure of the symposium itself and the papers selected represent current thinking the the wide field of transportation, and the areas of rail (6 papers, three on railway signalling), air including space (two papers), road (one paper), road and rail (two papers) and sea (three papers) are covered. There are four papers concerned with general transport issues. Three papers concerned with the transport of radioactive materials are indexed separately. (author)

Laser additive manufacturing of high-performance materials

CERN Document Server

Gu, Dongdong

2015-01-01

This book entitled “Laser Additive Manufacturing of High-Performance Materials” covers the specific aspects of laser additive manufacturing of high-performance new materials components based on an unconventional materials incremental manufacturing philosophy, in terms of materials design and preparation, process control and optimization, and theories of physical and chemical metallurgy. This book describes the capabilities and characteristics of the development of new metallic materials components by laser additive manufacturing process, including nanostructured materials, in situ composite materials, particle reinforced metal matrix composites, etc. The topics presented in this book, similar as laser additive manufacturing technology itself, show a significant interdisciplinary feature, integrating laser technology, materials science, metallurgical engineering, and mechanical engineering. This is a book for researchers, students, practicing engineers, and manufacturing industry professionals interested i...

Method for a reliable activation calculation of core components; Methode zur zuverlaessigen Berechnung von Aktivierungen in Kernbauteilen

Energy Technology Data Exchange (ETDEWEB)

Mispagel, T.; Phlippen, P.W.; Rose, J. [Wissenschaftlich-Technische Ingenieurberatung GmbH (WTI), Juelich (Germany)

2013-07-01

During nuclear power plant operation components and materials are exposed to the neutron flux from the reactor core and radionuclides are produced. After removal of the fuel elements the radioactivity of these radionuclides in the reactor pressure vessel and the core internals provide more than 99% of the activity of the power plant. For the transport, the interim storage and the final disposal of these radioactive components the radioactive inventories have to be decoded with respect to radiation and nuclides. The declaration of the nuclide and activity inventories requires a reliable calculation of neutron induced activation of reactor components. These activation calculations describe the pile-up of nuclides due to irradiation and due to the decay of nuclides. For an optimum usage of the activity capacities of the repository Konrad it is necessary to have a qualified calculation procedure that keeps the conservatism as low as possible.

Reliability Analysis of 6-Component Star Markov Repairable System with Spatial Dependence

Directory of Open Access Journals (Sweden)

Liying Wang

2017-01-01

Full Text Available Star repairable systems with spatial dependence consist of a center component and several peripheral components. The peripheral components are arranged around the center component, and the performance of each component depends on its spatial “neighbors.” Vector-Markov process is adapted to describe the performance of the system. The state space and transition rate matrix corresponding to the 6-component star Markov repairable system with spatial dependence are presented via probability analysis method. Several reliability indices, such as the availability, the probabilities of visiting the safety, the degradation, the alert, and the failed state sets, are obtained by Laplace transform method and a numerical example is provided to illustrate the results.

Near term and long term materials issues and development needs for plasma interactive components

International Nuclear Information System (INIS)

Mattas, R.F.

1986-01-01

Plasma interactive components (PICs), including the first wall, limiter blades, divertor collector plates, halo scrapers, and RF launchers, are exposed to high particle fluxes that can result in high sputtering erosion rates and high heat fluxes. In addition, the materials in reactors are exposed to high neutron fluxes which will degrade the bulk properties. This severe environment will limit the materials and designs which can be used in fusion devices. In order to provide a reasonable degree of confidence that plasma interactive components will operate successfully, a comprehensive development program is needed. Materials research and development plays a key role in the successful development of PICs. The range of operating conditions along with a summary of the major issues for materials development is described. The areas covered include plasma/materials interactions, erosion/redeposition, baseline materials properties, fabrication, and irradiation damage effects. Candidate materials and materials development needs in the near term and long term are identified

Laser Beam Melting of Multi-Material Components

Science.gov (United States)

Laumer, Tobias; Karg, Michael; Schmidt, Michael

First results regarding the realisation of multi-material components manufactured by Laser Beam Melting of polymers and metals are published. For realising composite structures from polymer powders by additive manufacturing, at first relevant material properties regarding compatibility have to be analysed. The paper shows the main requirements for compatibility between different materials and offers first results in form of a compatibility matrix of possible combinations for composite structures. For achieving gradient properties of additively manufactured metal parts by using composite materials the composition of alloying components in the powder and adapted process strategies are varied. As an alternative to atomizing pre-alloyed materials, mixtures of different powders are investigated.

Chemical and biotechnological processing of collagen-containing raw materials into functional components of feed suitable for production of high-quality meat from farm animals

Science.gov (United States)

Baburina, M. I.; Ivankin, A. N.; Stanovova, I. A.

2017-09-01

The process of chemical biotechnological processing of collagen-containing raw materials into functional components of feeds for effective pig rearing was studied. Protein components of feeds were obtained as a result of hydrolysis in the presence of lactic acid of the animal collagen from secondary raw materials, which comprised subcutaneous collagen (cuticle), skin and veined mass with tendons from cattle. For comparison, a method is described for preparing protein components of feeds by cultivating Lactobacillus plantarum. Analysis of the kinetic data of the conversion of a high-molecular collagen protein to an aminolyte polypeptide mixture showed the advantage of microbiological synthesis in obtaining a protein for feeds. Feed formulations have been developed to include the components obtained, and which result in high quality pork suitable for the production of quality meat products.

Reliability Assessment of Offshore Wind Turbines Considering Faults of Electrical / Mechanical Components

DEFF Research Database (Denmark)

Kostandyan, Erik; Sørensen, John Dalsgaard

2013-01-01

For offshore wind turbines, the cost contribution to Cost of Energy from inspections and Operation & Maintenance can be substantial, and can be expected to increase when wind farms are placed at deeper water depths, further from the coast and in more harsh environments. Estimates of the reliability...... is considered and related to reliability estimation by taking into account faults e.g. due to failure of an electrical component or loss of grid....

Mechanical Properties for Reliability Analysis of Structures in Glassy Carbon

CERN Document Server

Garion, Cédric

2014-01-01

Despite its good physical properties, the glassy carbon material is not widely used, especially for structural applications. Nevertheless, its transparency to particles and temperature resistance are interesting properties for the applications to vacuum chambers and components in high energy physics. For example, it has been proposed for fast shutter valve in particle accelerator [1] [2]. The mechanical properties have to be carefully determined to assess the reliability of structures in such a material. In this paper, mechanical tests have been carried out to determine the elastic parameters, the strength and toughness on commercial grades. A statistical approach, based on the Weibull’s distribution, is used to characterize the material both in tension and compression. The results are compared to the literature and the difference of properties for these two loading cases is shown. Based on a Finite Element analysis, a statistical approach is applied to define the reliability of a structural component in gl...

Further HTGR core support structure reliability studies. Interim report No. 1

International Nuclear Information System (INIS)

Platus, D.L.

1976-01-01

Results of a continuing effort to investigate high temperature gas cooled reactor (HTGR) core support structure reliability are described. Graphite material and core support structure component physical, mechanical and strength properties required for the reliability analysis are identified. Also described are experimental and associated analytical techniques for determining the required properties, a procedure for determining number of tests required, properties that might be monitored by special surveillance of the core support structure to improve reliability predictions, and recommendations for further studies. Emphasis in the study is directed towards developing a basic understanding of graphite failure and strength degradation mechanisms; and validating analytical methods for predicting strength and strength degradation from basic material properties

Identification of high performance and component technology for space electrical power systems for use beyond the year 2000

Science.gov (United States)

Maisel, James E.

1988-01-01

Addressed are some of the space electrical power system technologies that should be developed for the U.S. space program to remain competitive in the 21st century. A brief historical overview of some U.S. manned/unmanned spacecraft power systems is discussed to establish the fact that electrical systems are and will continue to become more sophisticated as the power levels appoach those on the ground. Adaptive/Expert power systems that can function in an extraterrestrial environment will be required to take an appropriate action during electrical faults so that the impact is minimal. Manhours can be reduced significantly by relinquishing tedious routine system component maintenance to the adaptive/expert system. By cataloging component signatures over time this system can set a flag for a premature component failure and thus possibly avoid a major fault. High frequency operation is important if the electrical power system mass is to be cut significantly. High power semiconductor or vacuum switching components will be required to meet future power demands. System mass tradeoffs have been investigated in terms of operating at high temperature, efficiency, voltage regulation, and system reliability. High temperature semiconductors will be required. Silicon carbide materials will operate at a temperature around 1000 K and the diamond material up to 1300 K. The driver for elevated temperature operation is that radiator mass is reduced significantly because of inverse temperature to the fourth power.

Reliability models for a nonrepairable system with heterogeneous components having a phase-type time-to-failure distribution

International Nuclear Information System (INIS)

Kim, Heungseob; Kim, Pansoo

2017-01-01

This research paper presents practical stochastic models for designing and analyzing the time-dependent reliability of nonrepairable systems. The models are formulated for nonrepairable systems with heterogeneous components having phase-type time-to-failure distributions by a structured continuous time Markov chain (CTMC). The versatility of the phase-type distributions enhances the flexibility and practicality of the systems. By virtue of these benefits, studies in reliability engineering can be more advanced than the previous studies. This study attempts to solve a redundancy allocation problem (RAP) by using these new models. The implications of mixing components, redundancy levels, and redundancy strategies are simultaneously considered to maximize the reliability of a system. An imperfect switching case in a standby redundant system is also considered. Furthermore, the experimental results for a well-known RAP benchmark problem are presented to demonstrate the approximating error of the previous reliability function for a standby redundant system and the usefulness of the current research. - Highlights: • Phase-type time-to-failure distribution is used for components. • Reliability model for nonrepairable system is developed using Markov chain. • System is composed of heterogeneous components. • Model provides the real value of standby system reliability not an approximation. • Redundancy allocation problem is used to show usefulness of this model.

Compilation of the calculation elements of the electronic equipments reliability

International Nuclear Information System (INIS)

Lefevre, R.; D'Harcourt, A.; Dupuy, G.

1968-01-01

The aim of this work is to allow the practical execution of the estimated calculation of the electronic devices reliability and to standardize the source and the approach of the calculations while giving a systematic character to their execution mode. The systematic character of the calculations allows a comparison of the reliability of different materials and a rapid control of the calculations validity; at last, it brings out the use conditions of all the components of a set. A reliability calculation made according to the method described here reveals: -components badly used -the relative influence on the reliability of the set, of a component or a components group taking into account of the number, of the characteristics and of the use of these ones. At last, the results of the calculation allows to organize the exploitation (availability) and the maintenance (staff, stock of components) of the materials. The failure rates given in this book are only relating to the components service-life and do not correspond to precocious failures. (authors) [fr

High thermal load component

International Nuclear Information System (INIS)

Fuse, Toshiaki; Tachikawa, Nobuo.

1996-01-01

A cooling tube made of a pure copper is connected to the inner portion of an armour (heat resistant member) made of an anisotropic carbon/carbon composite (CFC) material. The CFC material has a high heat conductivity in longitudinal direction of fibers and has low conductivity in perpendicular thereto. Fibers extending in the armour from a heat receiving surface just above the cooling tube are directly connected to the cooling tube. A portion of the fibers extending from a heat receiving surface other than portions not just above the cooling tube is directly bonded to the cooling tube. Remaining fibers are disposed so as to surround the cooling tube. The armour and the cooling tube are soldered using an active metal flux. With such procedures, high thermal load components for use in a thermonuclear reactor are formed, which are excellent in a heat removing characteristic and hardly causes defects such as crackings and peeling. (I.N.)

1982 Annual status report: high-temperature materials

International Nuclear Information System (INIS)

Van de Voorde, M.

1983-01-01

The High Temperature Materials Programme is executed at the JRC, Petten Establishment and has for the 1980/83 programme period the objective to promote within the European Community the development of high temperature materials required for future energy technologies. Materials and engineering studies include: corrosion with or without load, mechanical properties under static or dynamic loads, surface protection creep of tubular components in corrosive environments and high temperature materials data bank

Developing Reliable Life Support for Mars

Science.gov (United States)

Jones, Harry W.

2017-01-01

A human mission to Mars will require highly reliable life support systems. Mars life support systems may recycle water and oxygen using systems similar to those on the International Space Station (ISS). However, achieving sufficient reliability is less difficult for ISS than it will be for Mars. If an ISS system has a serious failure, it is possible to provide spare parts, or directly supply water or oxygen, or if necessary bring the crew back to Earth. Life support for Mars must be designed, tested, and improved as needed to achieve high demonstrated reliability. A quantitative reliability goal should be established and used to guide development t. The designers should select reliable components and minimize interface and integration problems. In theory a system can achieve the component-limited reliability, but testing often reveal unexpected failures due to design mistakes or flawed components. Testing should extend long enough to detect any unexpected failure modes and to verify the expected reliability. Iterated redesign and retest may be required to achieve the reliability goal. If the reliability is less than required, it may be improved by providing spare components or redundant systems. The number of spares required to achieve a given reliability goal depends on the component failure rate. If the failure rate is under estimated, the number of spares will be insufficient and the system may fail. If the design is likely to have undiscovered design or component problems, it is advisable to use dissimilar redundancy, even though this multiplies the design and development cost. In the ideal case, a human tended closed system operational test should be conducted to gain confidence in operations, maintenance, and repair. The difficulty in achieving high reliability in unproven complex systems may require the use of simpler, more mature, intrinsically higher reliability systems. The limitations of budget, schedule, and technology may suggest accepting lower and

Report on the joint meeting of the Division of Development and Technology Plasma Wall Interaction and High Heat Flux Materials and Components task groups

International Nuclear Information System (INIS)

Nygren, R.E.

1992-04-01

The Plasma/Wall Interaction and High Heat Flux Materials and Components Task Groups typically hold a joint meeting each year to provide a forum for discussion of technical issues of current interest as well as an opportunity for program reviews by the Department of Energy (DOE). At the meeting in September 1990, reported here, research programs in support of the International Thermonuclear Experimental Reactor (ITER) were highlighted. The first part of the meeting was devoted to research and development (R ampersand D) for ITER on plasma facing components plus introductory presentations on some current projects and design studies. The balance of the meeting was devoted to program reviews, which included presentations by most of the participants in the Small Business Innovative Research (SBIR) Programs with activities related to plasma wall interactions. The Task Groups on Plasma/Wall Interaction and on High Heat Flux Materials and Components were chartered as continuing working groups by the Division of Development and Technology in DOE's Magnetic Fusion Program. This report is an addition to the series of ''blue cover'' reports on the Joint Meetings of the Plasma/Wall Interaction and High Heat Flux Materials and Components Task Groups. Among several preceding meetings were those in October 1989 and January 1988

The role of NDE in maintaining and extending the life cycle of engineering components

International Nuclear Information System (INIS)

Doctor, S.R.

1997-01-01

A successful life cycle of engineering components begins during the design to select the best materials for a given application, designing for economical maintenance, and accommodating NDE inspections. NDE in the nuclear industry is part of the defense in depth to insure structural integrity of components. High reliability NDE is needed to reliably detect and accurately characterize the failure modes that have occurred in nuclear components. The move toward risk-informed inservice inspection programs focusses the NDE on the most safety significant components. The use of performance demonstration testing is leading to improved inservice inspections through screening out ineffective procedure/equipment/personnel. (orig.)

Examples of fatigue lifetime and reliability evaluation of larger wind turbine components

DEFF Research Database (Denmark)

Tarp-Johansen, N.J.

2003-01-01

This report is one out of several that constitute the final report on the ELSAM funded PSO project “Vindmøllekomponenters udmattelsesstyrke og levetid”, project no. 2079, which regards the lifetime distribution of larger wind turbine components in ageneric turbine that has real life dimensions....... Though it was the initial intention of the project to consider only the distribution of lifetimes the work reported in this document provides also calculations of reliabilities and partial load safetyfactors under specific assumptions about uncertainty sources, as reliabilities are considered...

Reliability analysis of reinforced concrete grids with nonlinear material behavior

Energy Technology Data Exchange (ETDEWEB)

Neves, Rodrigo A [EESC-USP, Av. Trabalhador Sao Carlense, 400, 13566-590 Sao Carlos (Brazil); Chateauneuf, Alaa [LaMI-UBP and IFMA, Campus de Clermont-Fd, Les Cezeaux, BP 265, 63175 Aubiere cedex (France)]. E-mail: alaa.chateauneuf@ifma.fr; Venturini, Wilson S [EESC-USP, Av. Trabalhador Sao Carlense, 400, 13566-590 Sao Carlos (Brazil)]. E-mail: venturin@sc.usp.br; Lemaire, Maurice [LaMI-UBP and IFMA, Campus de Clermont-Fd, Les Cezeaux, BP 265, 63175 Aubiere cedex (France)

2006-06-15

Reinforced concrete grids are usually used to support large floor slabs. These grids are characterized by a great number of critical cross-sections, where the overall failure is usually sudden. However, nonlinear behavior of concrete leads to the redistribution of internal forces and accurate reliability assessment becomes mandatory. This paper presents a reliability study on reinforced concrete (RC) grids based on coupling Monte Carlo simulations with the response surface techniques. This approach allows us to analyze real RC grids with large number of failure components. The response surface is used to evaluate the structural safety by using first order reliability methods. The application to simple grids shows the interest of the proposed method and the role of moment redistribution in the reliability assessment.

The mechanical behavior and reliability prediction of the HTR graphite component at various temperature and neutron dose ranges

International Nuclear Information System (INIS)

Fang, Xiang; Yu, Suyuan; Wang, Haitao; Li, Chenfeng

2014-01-01

Highlights: • The mechanical behavior of graphite component in HTRs under high temperature and neutron irradiation conditions is simulated. • The computational process of mechanical analysis is introduced. • Deformation, stresses and failure probability of the graphite component are obtained and discussed. • Various temperature and neutron dose ranges are selected in order to investigate the effect of in-core conditions on the results. - Abstract: In a pebble-bed high temperature gas-cooled reactor (HTR), nuclear graphite serves as the main structural material of the side reflectors. The reactor core is made up of a large number of graphite bricks. In the normal operation case of the reactor, the maximum temperature of the helium coolant commonly reaches about 750 °C. After around 30 years’ full power operation, the peak value of in-core fast neutron cumulative dose reaches to 1 × 10 22 n cm −2 (EDN). Such high temperature and neutron irradiation strongly impact the behavior of graphite component, causing obvious deformation. The temperature and neutron dose are unevenly distributed inside a graphite brick, resulting in stress concentrations. The deformation and stress concentration can both greatly affect safety and reliability of the graphite component. In addition, most of the graphite properties (such as Young's modulus and coefficient of thermal expansion) change remarkably under high temperature and neutron irradiations. The irradiation-induced creep also plays a very important role during the whole process, and provides a significant impact on the stress accumulation. In order to simulate the behavior of graphite component under various in-core conditions, all of the above factors must be considered carefully. In this paper, the deformation, stress distribution and failure probability of a side graphite component are studied at various temperature points and neutron dose levels. 400 °C, 500 °C, 600 °C and 750 °C are selected as the

Material Selection for an Ultra High Strength Steel Component Based on the Failure Criteria of CrachFEM

International Nuclear Information System (INIS)

Kessler, L.; Beier, Th.; Werner, H.; Horstkott, D.; Dell, H.; Gese, H.

2005-01-01

An increasing use of combining more than one process step is noticed for coupling crash simulations with the results of forming operations -- mostly by inheriting the forming history like plastic strain and material hardening. Introducing a continuous failure model allows a further benefit of these coupling processes; it sometimes can even be the most attractive result of such a work. In this paper the algorithm CrachFEM for fracture prediction has been used to generate more benefit of the successive forming and crash simulations -- especially for ultra high strength steels. The choice and selection of the material grade in combination with the component design can therefore be done far before the prototyping might show an unsuccessful crash result; and in an industrial applicable manner

Sub-nanosecond jitter, repetitive impulse generators for high reliability applications

International Nuclear Information System (INIS)

Krausse, G.J.; Sarjeant, W.J.

1981-01-01

Low jitter, high reliability impulse generator development has recently become of ever increasing importance for developing nuclear physics and weapons applications. The research and development of very low jitter (< 30 ps), multikilovolt generators for high reliability, minimum maintenance trigger applications utilizing a new class of high-pressure tetrode thyratrons now commercially available are described. The overall system design philosophy is described followed by a detailed analysis of the subsystem component elements. A multi-variable experimental analysis of this new tetrode thyratron was undertaken, in a low-inductance configuration, as a function of externally available parameters. For specific thyratron trigger conditions, rise times of 18 ns into 6.0-Ω loads were achieved at jitters as low as 24 ps. Using this database, an integrated trigger generator system with solid-state front-end is described in some detail. The generator was developed to serve as the Master Trigger Generator for a large neutrino detector installation at the Los Alamos Meson Physics Facility

Durability of building materials and components

CERN Document Server

Delgado, JMPQ

2013-01-01

Durability of Building Materials and Components provides a collection of recent research works to contribute to the systematization and dissemination of knowledge related to the long-term performance and durability of construction and, simultaneously, to show the most recent advances in this domain. It includes a set of new developments in the field of durability, service life prediction methodologies, the durability approach for historical and old buildings, asset and maintenance management and on the durability of materials, systems and components. The book is divided in several chapters that intend to be a resume of the current state of knowledge for benefit of professional colleagues.

Material and structural mechanical modelling and reliability of thin-walled bellows at cryogenic temperatures. Application to LHC compensation system

CERN Document Server

Garion, Cédric; Skoczen, Blazej

The present thesis is dedicated to the behaviour of austenitic stainless steels at cryogenic temperatures. The plastic strain induced martensitic transformation and ductile damage are taken into account in an elastic-plastic material modelling. The kinetic law of →’ transformation and the evolution laws of kinematic/isotropic mixed hardening are established. Damage issue is analysed by different ways: mesoscopic isotropic or orthotropic model and a microscopic approach. The material parameters are measured from 316L fine gauge sheet at three levels of temperature: 293 K, 77 K and 4.2 K. The model is applied to thin-walled corrugated shell, used in the LHC interconnections. The influence of the material properties on the stability is studied by a modal analysis. The reliability of the components, defined by the Weibull distribution law, is analysed from fatigue tests. The impact on reliability of geometrical imperfections and thermo-mechanical loads is also analysed.

Planned reliability in the transport and installation of large nuclear components

International Nuclear Information System (INIS)

Bieler, L.

1988-01-01

The transport and installation of heavy and bulky large components require detailed planning of all jobs and activities, trained and experienced personnel and corresponding technical equipment for reliable and quality-assured implementation. The correct approach to the planning and implementation of such transports and installations has been confirmed by years of successful performance of these jobs e.g. in reactor pressure vessels and steam generators for nuclear power plants. Large components for nuclear power plants are truly extreme examples but will be all the better suited for demonstrating the problems inherent in transport and installation. (orig.) [de

Evolving inspection technologies for reliable condition assessment of components and plants

International Nuclear Information System (INIS)

Baldev Raj

1994-01-01

Condition assessment of components and plants are being done regularly in many an industry. The methodologies adopted are being continuously refined. However, each of these methodologies are being applied in isolation, without realizing the synergistic advantage we derive when a global approach is taken for condition assessment. Developments in a variety of fields, that have a definite bearing on the reliability of condition assessment, are not applied (or even thought that they could be applied) together. The possible impact of evolving technologies in enhancing the efficiency of condition assessment of components and plants are discussed. (author). 11 refs

Performance and Reliability of Bonded Interfaces for High-Temperature Packaging

Energy Technology Data Exchange (ETDEWEB)

Paret, Paul P [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2017-08-02

Sintered silver has proven to be a promising candidate for use as a die-attach and substrate-attach material in automotive power electronics components. It holds promise of greater reliability than lead-based and lead-free solders, especially at higher temperatures (>200 degrees C). Accurate predictive lifetime models of sintered silver need to be developed and its failure mechanisms thoroughly characterized before it can be deployed as a die-attach or substrate-attach material in wide-bandgap device-based packages. Mechanical characterization tests that result in stress-strain curves and accelerated tests that produce cycles-to-failure result will be conducted. Also, we present a finite element method (FEM) modeling methodology that can offer greater accuracy in predicting the failure of sintered silver under accelerated thermal cycling. A fracture mechanics-based approach is adopted in the FEM model, and J-integral/thermal cycle values are computed.

Advanced qualification methodology for actively cooled plasma facing components

Science.gov (United States)

Durocher, A.; Escourbiac, F.; Grosman, A.; Boscary, J.; Merola, M.; Cismondi, F.; Courtois, X.; Farjon, J. L.; Missirlian, M.; Schlosser, J.; Tivey, R.

2007-12-01

The use of high heat flux plasma facing components (PFCs) in steady state fusion devices requires high reliability. These components have to withstand heat fluxes in the range 10-20 MW m-2 involving a number of severe engineering constraints. Feedback from the experience of various industrial manufacturings showed that the bonding of the refractory armour material onto the metallic heat sink causes generic difficulties strongly depending on material qualities and specific design. As the heat exhaust capability and lifetime of PFCs during plasma operation are directly linked to the manufacturing quality, a set of qualification activities such as active infrared thermography, lock-in and acoustic measurements were performed during the component development phases following a qualification route. This paper describes the major improvements stemming from better measurement accuracy and refined data processing and analyses recent developments aimed at investigating the capability to qualify the component in situ during its lifetime.

Advanced qualification methodology for actively cooled plasma facing components

International Nuclear Information System (INIS)

Durocher, A.; Escourbiac, F.; Grosman, A.; Boscary, J.; Merola, M.; Cismondi, F.; Courtois, X.; Farjon, J.L.; Missirlian, M.; Schlosser, J.; Tivey, R.

2007-01-01

The use of high heat flux plasma facing components (PFCs) in steady state fusion devices requires high reliability. These components have to withstand heat fluxes in the range 10-20 MW m -2 involving a number of severe engineering constraints. Feedback from the experience of various industrial manufacturings showed that the bonding of the refractory armour material onto the metallic heat sink causes generic difficulties strongly depending on material qualities and specific design. As the heat exhaust capability and lifetime of PFCs during plasma operation are directly linked to the manufacturing quality, a set of qualification activities such as active infrared thermography, lock-in and acoustic measurements were performed during the component development phases following a qualification route. This paper describes the major improvements stemming from better measurement accuracy and refined data processing and analyses recent developments aimed at investigating the capability to qualify the component in situ during its lifetime

Reliability of structural materials in nuclear industry

International Nuclear Information System (INIS)

Pinard Legry, G.

1996-01-01

The reliability of nuclear installations is a fundamental point for the exploitation of nuclear energy. It requires an extensive knowledge of the behaviour of materials in the operating conditions and during the expected service life of the installations. In nuclear power plants multiple risks of failure can exist and are expressed by corrosion and deformation phenomena or by modification in the mechanical characteristics of materials. The knowledge of the evolution with time of a given material requires to take into account the data relative to the material itself, to its environment and to the physical conditions of this environment. The study of materials aging needs a more precise knowledge of the kinetics of phenomena at any scale and of their interactions, and a micro- or macro-modeling of their behaviour during long periods of time. This paper gives an overview of the aging phenomena that occur in the structural materials involved in PWR and fast neutron reactors: thermal aging, generalized corrosion, corrosion under constraint, intergranular corrosion, crack growth under loading, wear, irradiation etc.. (J.S.)

Reliability and maintainability assessment factors for reliable fault-tolerant systems

Science.gov (United States)

Bavuso, S. J.

1984-01-01

A long term goal of the NASA Langley Research Center is the development of a reliability assessment methodology of sufficient power to enable the credible comparison of the stochastic attributes of one ultrareliable system design against others. This methodology, developed over a 10 year period, is a combined analytic and simulative technique. An analytic component is the Computer Aided Reliability Estimation capability, third generation, or simply CARE III. A simulative component is the Gate Logic Software Simulator capability, or GLOSS. The numerous factors that potentially have a degrading effect on system reliability and the ways in which these factors that are peculiar to highly reliable fault tolerant systems are accounted for in credible reliability assessments. Also presented are the modeling difficulties that result from their inclusion and the ways in which CARE III and GLOSS mitigate the intractability of the heretofore unworkable mathematics.

Test-retest reliability of cognitive EEG

Science.gov (United States)

McEvoy, L. K.; Smith, M. E.; Gevins, A.

2000-01-01

OBJECTIVE: Task-related EEG is sensitive to changes in cognitive state produced by increased task difficulty and by transient impairment. If task-related EEG has high test-retest reliability, it could be used as part of a clinical test to assess changes in cognitive function. The aim of this study was to determine the reliability of the EEG recorded during the performance of a working memory (WM) task and a psychomotor vigilance task (PVT). METHODS: EEG was recorded while subjects rested quietly and while they performed the tasks. Within session (test-retest interval of approximately 1 h) and between session (test-retest interval of approximately 7 days) reliability was calculated for four EEG components: frontal midline theta at Fz, posterior theta at Pz, and slow and fast alpha at Pz. RESULTS: Task-related EEG was highly reliable within and between sessions (r0.9 for all components in WM task, and r0.8 for all components in the PVT). Resting EEG also showed high reliability, although the magnitude of the correlation was somewhat smaller than that of the task-related EEG (r0.7 for all 4 components). CONCLUSIONS: These results suggest that under appropriate conditions, task-related EEG has sufficient retest reliability for use in assessing clinical changes in cognitive status.

Reliability modeling of digital component in plant protection system with various fault-tolerant techniques

International Nuclear Information System (INIS)

Kim, Bo Gyung; Kang, Hyun Gook; Kim, Hee Eun; Lee, Seung Jun; Seong, Poong Hyun

2013-01-01

Highlights: • Integrated fault coverage is introduced for reflecting characteristics of fault-tolerant techniques in the reliability model of digital protection system in NPPs. • The integrated fault coverage considers the process of fault-tolerant techniques from detection to fail-safe generation process. • With integrated fault coverage, the unavailability of repairable component of DPS can be estimated. • The new developed reliability model can reveal the effects of fault-tolerant techniques explicitly for risk analysis. • The reliability model makes it possible to confirm changes of unavailability according to variation of diverse factors. - Abstract: With the improvement of digital technologies, digital protection system (DPS) has more multiple sophisticated fault-tolerant techniques (FTTs), in order to increase fault detection and to help the system safely perform the required functions in spite of the possible presence of faults. Fault detection coverage is vital factor of FTT in reliability. However, the fault detection coverage is insufficient to reflect the effects of various FTTs in reliability model. To reflect characteristics of FTTs in the reliability model, integrated fault coverage is introduced. The integrated fault coverage considers the process of FTT from detection to fail-safe generation process. A model has been developed to estimate the unavailability of repairable component of DPS using the integrated fault coverage. The new developed model can quantify unavailability according to a diversity of conditions. Sensitivity studies are performed to ascertain important variables which affect the integrated fault coverage and unavailability

Design, construction, qualification and reliability of main components, from the safety aspect

International Nuclear Information System (INIS)

Crette, J.P.

1982-01-01

In FRANCE, the design and construction of reliable components, which condition the safe operation and availability of breeder plants, is based on the experience acquired during the operation of RAPSODIE, PHENIX and the various test facilities. The technical progress achieved on all main components is illustrated by examples taken from the CREYS-MALVILLE plant. In parallel with the development of these components, an extensive program covering research, development and the definition of design, construction and inspection rules, together with scheduling and quality assurance methods, prepares the industrialization of this reactor system, in compliance with the rules and recommendations issued by the pertinent safety authorities

A review of the reliability analysis of LPRS including the components repairs

International Nuclear Information System (INIS)

Oliveira, L.F.S. de; Fleming, P.V.; Frutuoso e Melo, P.F.F.; Tayt-Sohn, L.C.

1983-01-01

The reliability analysis of low pressure recirculation system in its long-term recicurlation phase before 24hs is presented. The possibility of repairing the components out of the containment is included. A general revision of analysis of the short-term recirculation phase is done. (author) [pt

Development of High-frequency Soft Magnetic Materials for Power Electronics

Directory of Open Access Journals (Sweden)

LIU Jun-chang

2017-05-01

Full Text Available The new requirements of high-frequency magnetic properties are put forward for electronic components with the rapid development of power electronics industry and the use of new electromagnetic materials. The properties of magnetic core, which is the key unit of electronic components, determine the performance of electronic components directly. Therefore, it's necessary to study the high-frequency soft magnetic materials. In this paper, the development history of four types of soft magnetic materials was reviewed. The advantages and disadvantages of each kind of soft magnetic materials and future development trends were pointed out. The emphases were placed on the popular soft magnetic composite materials in recent years. The tendency is to develop high-frequency soft magnetic composite materials with the particle size controllable, uniform coating layer on the core and a mass production method from laboratory to industrialization.

Quality and reliability assurance of electronic components in small-scale and middle-sized plants

International Nuclear Information System (INIS)

Becker, P.

1982-01-01

Electronic components are forever finding their way into new fields of application and have an ever increasing influence on the quality and reliability of the products in which they are used. The user has very negligible influence on the production methods used for the manufacture of the components and the element properties. (orig.) [de

Ultra Reliable Closed Loop Life Support for Long Space Missions

Science.gov (United States)

Jones, Harry W.; Ewert, Michael K.

2010-01-01

Spacecraft human life support systems can achieve ultra reliability by providing sufficient spares to replace all failed components. The additional mass of spares for ultra reliability is approximately equal to the original system mass, provided that the original system reliability is not too low. Acceptable reliability can be achieved for the Space Shuttle and Space Station by preventive maintenance and by replacing failed units. However, on-demand maintenance and repair requires a logistics supply chain in place to provide the needed spares. In contrast, a Mars or other long space mission must take along all the needed spares, since resupply is not possible. Long missions must achieve ultra reliability, a very low failure rate per hour, since they will take years rather than weeks and cannot be cut short if a failure occurs. Also, distant missions have a much higher mass launch cost per kilogram than near-Earth missions. Achieving ultra reliable spacecraft life support systems with acceptable mass will require a well-planned and extensive development effort. Analysis must determine the reliability requirement and allocate it to subsystems and components. Ultra reliability requires reducing the intrinsic failure causes, providing spares to replace failed components and having "graceful" failure modes. Technologies, components, and materials must be selected and designed for high reliability. Long duration testing is needed to confirm very low failure rates. Systems design should segregate the failure causes in the smallest, most easily replaceable parts. The system must be designed, developed, integrated, and tested with system reliability in mind. Maintenance and reparability of failed units must not add to the probability of failure. The overall system must be tested sufficiently to identify any design errors. A program to develop ultra reliable space life support systems with acceptable mass should start soon since it must be a long term effort.

Resiliency as a component importance measure in network reliability

International Nuclear Information System (INIS)

Whitson, John C.; Ramirez-Marquez, Jose Emmanuel

2009-01-01

This paper seeks to define the concept of resiliency as a component importance measure related to network reliability. Resiliency can be defined as a composite of: (1) the ability of a network to provide service despite external failures and (2) the time to restore service when in the presence of such failures. Although, Resiliency has been extensively studied in different research areas, this paper will study the specific aspects of quantifiable network resiliency when the network is experiencing potential catastrophic failures from external events and/or influences, and when it is not known a priori which specific components within the network will fail. A formal definition for Category I resiliency is proposed and a step-by-step approach based on Monte-Carlo simulation to calculate it is defined. To illustrate the approach, two-terminal networks with varying degrees of redundancy, have been considered. The results obtained for test networks show that this new quantifiable concept of resiliency provides insight into the performance and topology of the network. Future use for this work could include methods for safeguarding critical network components and optimizing the use of redundancy as a technique to improve network resiliency.

Heavy steel casting components for power plants 'mega-components' made of high Cr-steels

Energy Technology Data Exchange (ETDEWEB)

Hanus, Reinhold [voestalpine Giesserei Linz GmbH, Linz (Austria)

2010-07-01

Steel castings of creep resistant steels play a key role in fossil fuel fired power plants for highly loaded components in the high and intermediate pressure section of the turbines. Inner and outer casings, valve casings, inlet connections and elbows are examples of such critical components. The most important characteristic in a power plant is the efficiency, which mainly drives the CO2-emission. As a consequence of steadily improving power plant efficiencies and ever stricter emission standards, steam parameters become more critical and the creep resistance of the cast materials must also be constantly improved. The foundries voestalpine Giesserei Linz and voestalpine Giesserei Traisen participated in the development of the new 9-10% Cr-steels for application up to 625 C/650 C and in the THERMIE project where Ni-base alloys for 700 C-power plants were developed. Beside the material development in the European research projects the commercial production had to be established for industrial processes and the newly developed materials have to be transferred from research into the commercial production of heavy cast components. After selecting the most promising alloy from the laboratory melts, welding tests were performed - mostly with matching electrodes also produced within COST/THERMIE. Base material and welds were investigated in respect of microstructure, creep resistance, mechanical properties and weldability. Heat treatment investigations were also necessary for optimization of the mechanical properties. Based on the results of these studies, pilot components and plates for testing welding processes were cast in order to verify the castability and weldability of larger parts and to make any necessary adjustments to chemical composition, heat treatment or welding parameters. Parallel to the ongoing creep tests within COST/THERMIE-program, the newly developed steel grades were introduced into the commercial production of large components. This involved finding

The selection of field component reliability data for use in nuclear safety studies

International Nuclear Information System (INIS)

Coxson, B.A.; Tabaie, Mansour

1990-01-01

The paper reviews the user requirements for field component failure data in nuclear safety studies, and the capability of various data sources to satisfy these requirements. Aspects such as estimating the population of items exposed to failure, incompleteness, and under-reporting problems are discussed. The paper takes as an example the selection of component reliability data for use in the Pre-Operational Safety Report (POSR) for Sizewell 'B' Power Station, where field data has in many cases been derived from equipment other than that to be procured and operated on site. The paper concludes that the main quality sought in the available data sources for such studies is the ability to examine failure narratives in component reliability data systems for equipment performing comparable duties to the intended plant application. The main benefit brought about in the last decade is the interactive access to data systems which are adequately structured with regard to the equipment covered, and also provide a text-searching capability of quality-controlled event narratives. (author)

Mechanical reliability of bulk high Tc superconductors

International Nuclear Information System (INIS)

Freiman, S.W.

1990-01-01

Most prospective applications for high T c superconductors in bulk form, e.g. magnets, motors, will require appreciable mechanical strength. Work at NIST [National Institute of Standards and Technology] has begun to address issues related to mechanical reliability. For example, recent studies on Ba-Y-Cu-O have shown that the intrinsic crack growth resistance, K IC , of crystals of this material is even smaller than was first reported, less than that of window glass, and is sensitive to moisture. Processing conditions, particularly sintering and annealing atmosphere, have been shown to have a major influence on microstructure and internal stresses in the material. Large internal stresses result from the tetragonal to orthorhombic phase transformation as well as the thermal expansion anisotropy in the grains of the ceramic. Because stress relief is absent, microcracks form which have a profound influence on strength

Mechanical factors affecting reliability of pressure components (fatigue, cracking)

International Nuclear Information System (INIS)

Lebey, J.; Garnier, C.; Roche, R.; Barrachin, B.

1978-01-01

The reliability of a pressure component can be seriously affected by the formation and development of cracks. The experimental studies presented in this paper are devoted to three different aspects of crack propagation phenomena which have been relatively little described. In close connection with safety analyses of PWR, the authors study the influence of the environment by carrying out fatigue tests with samples bathed in hot pressurized water. Ferritic, austenitic and Incolloy 800 steels were used and the results are presented in the form of fatigue curves in the oligocyclic region. The second part of the paper relates to crack initiation cirteria in ductile steels weakened by notches. The CT samples used make it possible to study almost all types of fracture (ductile, intermediate and brittle). The use of two criteria based on the load limit and on the toughness of the material constitutes a practical way of evaluating crack propagation conditions. A series of tests carried out on notched spherical vessels of different size shows that large vessels are relatively brittle; fast unstable fracture is observed as size increases. Crack growth rate in PWR primary circuits (3/6 steel) is studied on piping elements (0.25 scale) subjected to cyclic stress variations (285 0 C and with pressure varying between 1 and 160 bar in each cycle). By calculating the stress intensity factor, correlation with results obtained in the laboratory on CT samples is possible. (author)

A Simplified Method for Upscaling Composite Materials with High Contrast of the Conductivity

KAUST Repository

Ewing, R.; Iliev, O.; Lazarov, R.; Rybak, I.; Willems, J.

2009-01-01

A large class of industrial composite materials, such as metal foams, fibrous glass materials, mineral wools, and the like, are widely used in insulation and advanced heat exchangers. These materials are characterized by a substantial difference between the thermal properties of the highly conductive materials (glass or metal) and the insulator (air) as well as low volume fractions and complex network-like structures of the highly conductive components. In this paper we address the important issue for the engineering practice of developing fast, reliable, and accurate methods for computing the macroscopic (upscaled) thermal conductivities of such materials. We assume that the materials have constant macroscopic thermal conductivity tensors, which can be obtained by upscaling techniques based on the postprocessing of a number of linearly independent solutions of the steady-state heat equation on representative elementary volumes (REVs). We propose, theoretically justify, and computationally study a numerical method for computing the effective conductivities of materials for which the ratio δ of low and high conductivities satisfies δ ≪ 1. We show that in this case one needs to solve the heat equation in the region occupied by the highly conductive media only. Further, we prove that under certain conditions on the microscale geometry the proposed method gives an approximation that is O(δ)-close to the upscaled conductivity. Finally, we illustrate the accuracy and the limitations of the method on a number of numerical examples. © 2009 Society for Industrial and Applied Mathematics.

High reliability - low noise radionuclide signature identification algorithms for border security applications

Science.gov (United States)

Lee, Sangkyu

Illicit trafficking and smuggling of radioactive materials and special nuclear materials (SNM) are considered as one of the most important recent global nuclear threats. Monitoring the transport and safety of radioisotopes and SNM are challenging due to their weak signals and easy shielding. Great efforts worldwide are focused at developing and improving the detection technologies and algorithms, for accurate and reliable detection of radioisotopes of interest in thus better securing the borders against nuclear threats. In general, radiation portal monitors enable detection of gamma and neutron emitting radioisotopes. Passive or active interrogation techniques, present and/or under the development, are all aimed at increasing accuracy, reliability, and in shortening the time of interrogation as well as the cost of the equipment. Equally important efforts are aimed at advancing algorithms to process the imaging data in an efficient manner providing reliable "readings" of the interiors of the examined volumes of various sizes, ranging from cargos to suitcases. The main objective of this thesis is to develop two synergistic algorithms with the goal to provide highly reliable - low noise identification of radioisotope signatures. These algorithms combine analysis of passive radioactive detection technique with active interrogation imaging techniques such as gamma radiography or muon tomography. One algorithm consists of gamma spectroscopy and cosmic muon tomography, and the other algorithm is based on gamma spectroscopy and gamma radiography. The purpose of fusing two detection methodologies per algorithm is to find both heavy-Z radioisotopes and shielding materials, since radionuclides can be identified with gamma spectroscopy, and shielding materials can be detected using muon tomography or gamma radiography. These combined algorithms are created and analyzed based on numerically generated images of various cargo sizes and materials. In summary, the three detection

Reliability & availability of wind turbine electrical & electronic components

NARCIS (Netherlands)

Tavner, P.; Faulstich, S.; Hahn, B.; Bussel, van G.J.W.

2010-01-01

Recent analysis of European onshore wind turbine reliability data has shown that whilst wind turbine mechanical subassemblies tend to have relatively low failure rates but long downtimes, electrical and electronic subassemblies have relatively high failure rates and short downtimes. For onshore wind

Materials for Advanced Ultra-supercritical (A-USC) Steam Turbines – A-USC Component Demonstration

Energy Technology Data Exchange (ETDEWEB)

Purgert, Robert [Energy Industries Of Ohio Inc., Independence, OH (United States); Phillips, Jeffrey [Energy Industries Of Ohio Inc., Independence, OH (United States); Hendrix, Howard [Energy Industries Of Ohio Inc., Independence, OH (United States); Shingledecker, John [Energy Industries Of Ohio Inc., Independence, OH (United States); Tanzosh, James [Energy Industries Of Ohio Inc., Independence, OH (United States)

2016-10-01

The work by the United States Department of Energy (U.S. DOE)/Ohio Coal Development Office (OCDO) advanced ultra-supercritical (A-USC) Steam Boiler and Turbine Materials Consortia from 2001 through September 2015 was primarily focused on lab scale and pilot scale materials testing. This testing included air- or steam-cooled “loops” that were inserted into existing utility boilers to gain exposure of these materials to realistic conditions of high temperature and corrosion due to the constituents in the coal. Successful research and development resulted in metallic alloy materials and fabrication processes suited for power generation applications with metal temperatures up to approximately 1472°F (800°C). These materials or alloys have shown, in extensive laboratory tests and shop fabrication studies, to have excellent applicability for high-efficiency low CO₂ transformational power generation technologies previously mentioned. However, as valuable as these material loops have been for obtaining information, their scale is significantly below that required to minimize the risk associated with a power company building a multi-billion dollar A-USC power plant. To decrease the identified risk barriers to full-scale implementation of these advanced materials, the U.S. DOE/OCDO A-USC Steam Boiler and Turbine Materials Consortia identified the key areas of the technology that need to be tested at a larger scale. Based upon the recommendations and outcome of a Consortia-sponsored workshop with the U.S.’s leading utilities, a Component Test (ComTest) Program for A-USC was proposed. The A-USC ComTest program would define materials performance requirements, plan for overall advanced system integration, design critical component tests, fabricate components for testing from advanced materials, and carry out the tests. The AUSC Component Test was premised on the program occurring at multiple facilities, with the operating temperatures, pressure and/or size of

Structural materials requirements for in-vessel components of fusion power plants

International Nuclear Information System (INIS)

Schaaf, B. van der

2000-01-01

The economic production of fusion energy is determined by principal choices such as using magnetic plasma confinement or generating inertial fusion energy. The first generation power plants will use deuterium and tritium mixtures as fuel, producing large amounts of highly energetic neutrons resulting in radiation damage in materials. In the far future the advanced fuels, 3 He or 11 B, determine power plant designs with less radiation damage than in the first generation. The first generation power plants design must anticipate radiation damage. Solid sacrificing armour or liquid layers could limit component replacements costs to economic levels. There is more than radiation damage resistance to determine the successful application of structural materials. High endurance against cyclic loading is a prominent requirement, both for magnetic and inertial fusion energy power plants. For high efficiency and compactness of the plant, elevated temperature behaviour should be attractive. Safety and environmental requirements demand that materials have low activation potential and little toxic effects under both normal and accident conditions. The long-term contenders for fusion power plant components near the plasma are materials in the range from innovative steels, such as reduced activation ferritic martensitic steels, to highly advanced ceramic composites based on silicon carbide, and chromium alloys. The steels follow an evolutionary path to basic plant efficiencies. The competition on the energy market in the middle of the next century might necessitate the riskier but more rewarding development of SiCSiC composites or chromium alloys

Lead free solder mechanics and reliability

CERN Document Server

Pang, John Hock Lye

2012-01-01

Lead-free solders are used extensively as interconnection materials in electronic assemblies and play a critical role in the global semiconductor packaging and electronics manufacturing industry. Electronic products such as smart phones, notebooks and high performance computers rely on lead-free solder joints to connect IC chip components to printed circuit boards. Lead Free Solder: Mechanics and Reliability provides in-depth design knowledge on lead-free solder elastic-plastic-creep and strain-rate dependent deformation behavior and its application in failure assessment of solder joint reliability. It includes coverage of advanced mechanics of materials theory and experiments, mechanical properties of solder and solder joint specimens, constitutive models for solder deformation behavior; numerical modeling and simulation of solder joint failure subject to thermal cycling, mechanical bending fatigue, vibration fatigue and board-level drop impact tests. This book also: Discusses the mechanical prope...

Structural Reliability of Wind Turbine Blades

DEFF Research Database (Denmark)

Dimitrov, Nikolay Krasimirov

turbine blades. The main purpose is to draw a clear picture of how reliability-based design of wind turbines can be done in practice. The objectives of the thesis are to create methodologies for efficient reliability assessment of composite materials and composite wind turbine blades, and to map...... the uncertainties in the processes, materials and external conditions that have an effect on the health of a composite structure. The study considers all stages in a reliability analysis, from defining models of structural components to obtaining the reliability index and calibration of partial safety factors...... by developing new models and standards or carrying out tests The following aspects are covered in detail: ⋅ The probabilistic aspects of ultimate strength of composite laminates are addressed. Laminated plates are considered as a general structural reliability system where each layer in a laminate is a separate...

Thermal Management and Reliability of Automotive Power Electronics and Electric Machines

Energy Technology Data Exchange (ETDEWEB)

Narumanchi, Sreekant V [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Bennion, Kevin S [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Cousineau, Justine E [National Renewable Energy Laboratory (NREL), Golden, CO (United States); DeVoto, Douglas J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Feng, Xuhui [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kekelia, Bidzina [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kozak, Joseph P [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Major, Joshua [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Moreno, Gilberto [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Paret, Paul P [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Tomerlin, Jeff J [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2018-02-09

Low-cost, high-performance thermal management technologies are helping meet aggressive power density, specific power, cost, and reliability targets for power electronics and electric machines. The National Renewable Energy Laboratory is working closely with numerous industry and research partners to help influence development of components that meet aggressive performance and cost targets through development and characterization of cooling technologies, and thermal characterization and improvements of passive stack materials and interfaces. Thermomechanical reliability and lifetime estimation models are important enablers for industry in cost-and time-effective design.

Stochastic Modeling Of Wind Turbine Drivetrain Components

DEFF Research Database (Denmark)

Rafsanjani, Hesam Mirzaei; Sørensen, John Dalsgaard

2014-01-01

reliable components are needed for wind turbine. In this paper focus is on reliability of critical components in drivetrain such as bearings and shafts. High failure rates of these components imply a need for more reliable components. To estimate the reliability of these components, stochastic models...... are needed for initial defects and damage accumulation. In this paper, stochastic models are formulated considering some of the failure modes observed in these components. The models are based on theoretical considerations, manufacturing uncertainties, size effects of different scales. It is illustrated how...

Effect of amplifier component maintenance on laser system availability and reliability for the US National Ignition Facility

International Nuclear Information System (INIS)

Erlandson, A.C.; Lambert, H.; Zapata, L.E.

1996-12-01

We have analyzed the availability and reliability of the flashlamp-pumped, Nd:glass amplifiers that, as a part of a laser now being designed for future experiments, in inertial confinement fusion (ICF), will be used in the National Ignition Facility (NIF). Clearly , in order for large ICF systems such as the NIF to operate effectively as a whole, all components must meet demanding availability and reliability requirements. Accordingly, the NIF amplifiers can achieve high reliability and availability by using reliable parts, and by using a cassette-based maintenance design that allows most key amplifier parts to be 1744 replaced within a few hours. In this way, parts that degrade slowly, as the laser slabs, silver reflectors, and blastshields can be expected to do, based on previous experience, can be replaced either between shots or during scheduled maintenance periods, with no effect on availability or reliability. In contrast, parts that fail rapidly, such as the flashlamps, can and do cause unavailability or unreliability. Our analysis demonstrates that the amplifiers for the NIF will meet availability and reliability goals, respectively, of 99.8% and 99.4%, provided that the 7680 NIF flashlamps in NIF have failure rates of less than, or equal to, those experienced on Nova, a 5000-lamp laser at Lawrence Livermore National Laboratory (LLNL)

Human Reliability Program Overview

Energy Technology Data Exchange (ETDEWEB)

Bodin, Michael

2012-09-25

This presentation covers the high points of the Human Reliability Program, including certification/decertification, critical positions, due process, organizational structure, program components, personnel security, an overview of the US DOE reliability program, retirees and academia, and security program integration.

Some reliability targets affecting the necessary provisions for in-service inspection and monitoring of LMFBR engineering components

International Nuclear Information System (INIS)

Bolt, P.R.

1980-01-01

The possible consequences of failure of primary and secondary sodium circuit components are discussed with particular reference to post incident fault diagnosis, remedial procedures and outage durations. The core support structures and steam generator units are identified as particularly important components in terms of economic consequence of their failure. Important safety considerations may also apply. Levels of reliability for core support and steam generator integrity, necessary to meet economic and certain safety criteria, are discussed and quantitative data is given. Possible failure and deterioration mechanisms which could result in unacceptable reductions in reliability are then identified for the core support and steam generator units. Following a consideration of the reliability targets and possible causes of loss of reliability, an appraisal is made of the necessary extent of in-service data to be obtained on component behaviour and condition. In-service inspection and monitoring methods that could be used to obtain this data are described. Consideration is given to UK and overseas inspection experience on LMFBR and other nuclear plant. (author)

Some reliability targets affecting the necessary provisions for in-service inspection and monitoring of LMFBR engineering components

Energy Technology Data Exchange (ETDEWEB)

Bolt, P R [Fast Reactor Engineering, Plant Engineering Department, CEGB, Barnwood, Gloucester (United Kingdom)

1980-11-01

The possible consequences of failure of primary and secondary sodium circuit components are discussed with particular reference to post incident fault diagnosis, remedial procedures and outage durations. The core support structures and steam generator units are identified as particularly important components in terms of economic consequence of their failure. Important safety considerations may also apply. Levels of reliability for core support and steam generator integrity, necessary to meet economic and certain safety criteria, are discussed and quantitative data is given. Possible failure and deterioration mechanisms which could result in unacceptable reductions in reliability are then identified for the core support and steam generator units. Following a consideration of the reliability targets and possible causes of loss of reliability, an appraisal is made of the necessary extent of in-service data to be obtained on component behaviour and condition. In-service inspection and monitoring methods that could be used to obtain this data are described. Consideration is given to UK and overseas inspection experience on LMFBR and other nuclear plant. (author)

Development of LTCC Materials with High Mechanical Strength

International Nuclear Information System (INIS)

Kawai, Shinya; Nishiura, Sousuke; Terashi, Yoshitake; Furuse, Tatsuji

2011-01-01

We have developed LTCC materials suitable for substrates of RF modules used in mobile phone. LTCC can provide excellent solutions to requirements of RF modules, such as down-sizing, embedded elements and high performance. It is also important that LTCC material has high mechanical strength to reduce risk of fracture by mechanical impact. We have established a method of material design for high mechanical strength. There are two successive steps in the concept to achieve high mechanical strength. The first step is to improve mechanical strength by increasing the Young's modulus, and the second step is either further improvement through the Young's modulus or enhancement of the fracture energy. The developed material, so called high-strength LTCC, thus possesses mechanical strength of 400MPa, which is twice as strong as conventional material whose mechanical strength is approximately 200MPa in typical. As a result, high-strength LTCC shows an excellent mechanical reliability, against the drop impact test for example. The paper presents material design and properties of LTCC materials.

Exact reliability quantification of highly reliable systems with maintenance

Energy Technology Data Exchange (ETDEWEB)

Bris, Radim, E-mail: radim.bris@vsb.c [VSB-Technical University Ostrava, Faculty of Electrical Engineering and Computer Science, Department of Applied Mathematics, 17. listopadu 15, 70833 Ostrava-Poruba (Czech Republic)

2010-12-15

When a system is composed of highly reliable elements, exact reliability quantification may be problematic, because computer accuracy is limited. Inaccuracy can be due to different aspects. For example, an error may be made when subtracting two numbers that are very close to each other, or at the process of summation of many very different numbers, etc. The basic objective of this paper is to find a procedure, which eliminates errors made by PC when calculations close to an error limit are executed. Highly reliable system is represented by the use of directed acyclic graph which is composed from terminal nodes, i.e. highly reliable input elements, internal nodes representing subsystems and edges that bind all of these nodes. Three admissible unavailability models of terminal nodes are introduced, including both corrective and preventive maintenance. The algorithm for exact unavailability calculation of terminal nodes is based on merits of a high-performance language for technical computing MATLAB. System unavailability quantification procedure applied to a graph structure, which considers both independent and dependent (i.e. repeatedly occurring) terminal nodes is based on combinatorial principle. This principle requires summation of a lot of very different non-negative numbers, which may be a source of an inaccuracy. That is why another algorithm for exact summation of such numbers is designed in the paper. The summation procedure uses benefits from a special number system with the base represented by the value 2{sup 32}. Computational efficiency of the new computing methodology is compared with advanced simulation software. Various calculations on systems from references are performed to emphasize merits of the methodology.

Experience with high heat flux components in large tokamaks

International Nuclear Information System (INIS)

Chappuis, P.; Dietz, K.J.; Ulrickson, M.

1991-01-01

The large present day tokamaks. i.e.JET, TFTR, JT-60, DIII-D and Tore Supra are machines capable of sustaining plasma currents of several million amperes. Pulse durations range from a few seconds up to a minute. These large machines have been in operation for several years and there exists wide experience with materials for plasma facing components. Bare and coated metals, bare and coated graphites and beryllium were used for walls, limiters and divertors. High heat flux components are mainly radiation cooled, but stationary cooling for long pulse duration is also employed. This paper summarizes the experience gained in the large machines with respect to material selection, component design, problem areas, and plasma performance. 2 tabs., 26 figs., 50 refs

Development of strength evaluation method for high-pressure ceramic components

Energy Technology Data Exchange (ETDEWEB)

Takegami, Hiroaki, E-mail: takegami.hiroaki@jaea.go.jp; Terada, Atsuhiko; Inagaki, Yoshiyuki

2014-05-01

Japan Atomic Energy Agency is conducting R and D on nuclear hydrogen production by the Iodine-Sulfur (IS) process. Since highly corrosive materials such as sulfuric and hydriodic acids are used in the IS process, it is very important to develop components made of corrosion resistant materials. Therefore, we have been developing a sulfuric acid decomposer made of a ceramic material, that is, silicon carbide (SiC), which shows excellent corrosion resistance to sulfuric acid. One of the key technological challenges for the practical use of a ceramic sulfuric acid decomposer made of SiC is to be licensed in accordance with the High Pressure Gas Safety Act for high-pressure operations of the IS process. Since the strength of a ceramic material depends on its geometric form, etc., the strength evaluation method required for a pressure design is not established. Therefore, we propose a novel strength evaluation method for SiC structures based on the effective volume theory in order to extend the range of application of the effective volume. We also developed a design method for ceramic apparatus with the strength evaluation method in order to obtain a license in accordance with the High Pressure Gas Safety Act. In this paper, the minimum strength of SiC components was calculated by Monte Carlo simulation, and the minimum strength evaluation method of SiC components was developed by using the results of simulation. The method was confirmed by fracture test of tube model and reference data.

Effect of residual stresses on the reliability of components under fatigue

International Nuclear Information System (INIS)

Ruestenberg, I.

1995-01-01

The assurance of the reliability of mechanical components relative to a variety of failure mechanisms is of decisive technical, industrial, and economic importance. In this dissertation, the reliability, i.e. the probability that the lifetime does not fall below a given value, is examined with respect to the particularly important failure mechanisms of fracture and fatigue. The general problem of uniaxial fatigue is studied on the basis of both continuum damage mechanics and crack mechanics. In particular, the mechanisms of crack initiation, as characterized by the Coffin-Manson-Neuber local strain-life equations for notched components as well as the mechanism of crack growth, as governed by the Paris-Erdogang relation, are taken into account. The nonlinear fatigue damage accumulation process for components subjected to general, cyclic loading histories is modeled by a multilinear damage law which allows, in principle, to characterize the subsequent activation of different fatigue mechanisms. Explicit equations are developed for quintuple-, quadruple-, and triple-linear damage accumulation. Particularly promising appears the triple-linear damage approach which allows, in principle, the identification of a nucleation, an initiation, and a final growth stage up to rupture of fatigue cracks. The beneficial effect of intentionally induced compressive residual stresses on the lifetime of the component is investigated. To this end, an elasto-plastic contact problem, based on Prandtl-Reuss' constitutive equations, is numerically solved, and the residual stress field, as it is typically produced by the mechanical process of cold rolling, is established. Assessments of the effect of adaptation, i.e. the subsequent reduction of the residual stresses due to cyclic in-service loading as well as of the effect of unavoidable surface roughness, introduced by manufacturing processes like forging, are carried out. (author) figs., tabs., refs

High Temperature Corrosion Problem of Boiler Components in presence of Sulfur and Alkali based Fuels

Science.gov (United States)

Ghosh, Debashis; Mitra, Swapan Kumar

2011-04-01

Material degradation and ageing is of particular concern for fossil fuel fired power plant components. New techniques/approaches have been explored in recent years for Residual Life assessment of aged components and material degradation due to different damage mechanism like creep, fatigue, corrosion and erosion etc. Apart from the creep, the high temperature corrosion problem in a fossil fuel fired boiler is a matter of great concern if the fuel contains sulfur, chlorine sodium, potassium and vanadium etc. This paper discusses the material degradation due to high temperature corrosion in different critical components of boiler like water wall, superheater and reheater tubes and also remedial measures to avoid the premature failure. This paper also high lights the Residual Life Assessment (RLA) methodology of the components based on high temperature fireside corrosion. of different critical components of boiler.

Failure analysis a practical guide for manufacturers of electronic components and systems

CERN Document Server

Bâzu, Marius

2011-01-01

Failure analysis is the preferred method to investigate product or process reliability and to ensure optimum performance of electrical components and systems. The physics-of-failure approach is the only internationally accepted solution for continuously improving the reliability of materials, devices and processes. The models have been developed from the physical and chemical phenomena that are responsible for degradation or failure of electronic components and materials and now replace popular distribution models for failure mechanisms such as Weibull or lognormal. Reliability engineers nee

Additive Manufacturing of Metallic and Ceramic Components by the Material Extrusion of Highly-Filled Polymers: A Review and Future Perspectives.

Science.gov (United States)

Gonzalez-Gutierrez, Joamin; Cano, Santiago; Schuschnigg, Stephan; Kukla, Christian; Sapkota, Janak; Holzer, Clemens

2018-05-18

Additive manufacturing (AM) is the fabrication of real three-dimensional objects from metals, ceramics, or plastics by adding material, usually as layers. There are several variants of AM; among them material extrusion (ME) is one of the most versatile and widely used. In MEAM, molten or viscous materials are pushed through an orifice and are selectively deposited as strands to form stacked layers and subsequently a three-dimensional object. The commonly used materials for MEAM are thermoplastic polymers and particulate composites; however, recently innovative formulations of highly-filled polymers (HP) with metals or ceramics have also been made available. MEAM with HP is an indirect process, which uses sacrificial polymeric binders to shape metallic and ceramic components. After removing the binder, the powder particles are fused together in a conventional sintering step. In this review the different types of MEAM techniques and relevant industrial approaches for the fabrication of metallic and ceramic components are described. The composition of certain HP binder systems and powders are presented; the methods of compounding and filament making HP are explained; the stages of shaping, debinding, and sintering are discussed; and finally a comparison of the parts produced via MEAM-HP with those produced via other manufacturing techniques is presented.

Additive Manufacturing of Metallic and Ceramic Components by the Material Extrusion of Highly-Filled Polymers: A Review and Future Perspectives

Science.gov (United States)

Cano, Santiago

2018-01-01

Additive manufacturing (AM) is the fabrication of real three-dimensional objects from metals, ceramics, or plastics by adding material, usually as layers. There are several variants of AM; among them material extrusion (ME) is one of the most versatile and widely used. In MEAM, molten or viscous materials are pushed through an orifice and are selectively deposited as strands to form stacked layers and subsequently a three-dimensional object. The commonly used materials for MEAM are thermoplastic polymers and particulate composites; however, recently innovative formulations of highly-filled polymers (HP) with metals or ceramics have also been made available. MEAM with HP is an indirect process, which uses sacrificial polymeric binders to shape metallic and ceramic components. After removing the binder, the powder particles are fused together in a conventional sintering step. In this review the different types of MEAM techniques and relevant industrial approaches for the fabrication of metallic and ceramic components are described. The composition of certain HP binder systems and powders are presented; the methods of compounding and filament making HP are explained; the stages of shaping, debinding, and sintering are discussed; and finally a comparison of the parts produced via MEAM-HP with those produced via other manufacturing techniques is presented. PMID:29783705

Computer Simulation of Material Flow in Warm-forming Bimetallic Components

Science.gov (United States)

Kong, T. F.; Chan, L. C.; Lee, T. C.

2007-05-01

Bimetallic components take advantage of two different metals or alloys so that their applicable performance, weight and cost can be optimized. However, since each material has its own flow properties and mechanical behaviour, heterogeneous material flows will occur during the bimetal forming process. Those controls of process parameters are relatively more complicated than forming single metals. Most previous studies in bimetal forming have focused mainly on cold forming, and less relevant information about the warm forming has been provided. Indeed, changes of temperature and heat transfer between two materials are the significant factors which can highly influence the success of the process. Therefore, this paper presents a study of the material flow in warm-forming bimetallic components using finite-element (FE) simulation in order to determine the suitable process parameters for attaining the complete die filling. A watch-case-like component made of stainless steel (AISI-316L) and aluminium alloy (AL-6063) was used as the example. The warm-forming processes were simulated with the punch speeds V of 40, 80, and 120 mm/s and the initial temperatures of the stainless steel TiSS of 625, 675, 725, 775, 825, 875, 925, 975, and 1025 °C. The results showed that the AL-6063 flowed faster than the AISI-316L and so the incomplete die filling was only found in the AISI-316L region. A higher TiSS was recommended to avoid incomplete die filling. The reduction of V is also suggested because this can save the forming energy and prevent the damage of tooling. Eventually, with the experimental verification, the results from the simulation were in agreement with those of the experiments. On the basis of the results of this study, engineers can gain a better understanding of the material flow in warm-forming bimetallic components, and be able to determine more efficiently the punch speed and initial material temperature for the process.

Some new high energy materials and their formulations for specialized applications

Energy Technology Data Exchange (ETDEWEB)

Agrawal, Jai Prakash [Directorate of Materials, DRDO HQrs, ' B' Wing, Sena Bhavan, New Delhi - 110 011 (India)

2005-10-01

Energetic materials form an integral part of most weapon systems and a large number of new high-energy materials: thermally stable explosives, high-performance explosives, melt-castable explosives, insensitive high explosives and energetic binders have been reported in the literature in recent years. Some explosive formulations based on these new energetic materials are also vaguely reported. This paper examines these materials and their formulations from the point of view of stability, reliability, safety and specific applications. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

One Component Encapsulating Material Matrix as High Barrier Coating, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — To address the NASA need for new flexible food packaging materials with effective high barrier against oxygen and moisture to protect food, minimize weight and...

Reactor materials program process water component failure probability

International Nuclear Information System (INIS)

Daugherty, W. L.

1988-01-01

The maximum rate loss of coolant accident for the Savannah River Production Reactors is presently specified as the abrupt double-ended guillotine break (DEGB) of a large process water pipe. This accident is not considered credible in light of the low applied stresses and the inherent ductility of the piping materials. The Reactor Materials Program was initiated to provide the technical basis for an alternate, credible maximum rate LOCA. The major thrust of this program is to develop an alternate worst case accident scenario by deterministic means. In addition, the probability of a DEGB is also being determined; to show that in addition to being mechanistically incredible, it is also highly improbable. The probability of a DEGB of the process water piping is evaluated in two parts: failure by direct means, and indirectly-induced failure. These two areas have been discussed in other reports. In addition, the frequency of a large bread (equivalent to a DEGB) in other process water system components is assessed. This report reviews the large break frequency for each component as well as the overall large break frequency for the reactor system

Investigation of deterioration mechanism of electrical ceramic insulating materials under high temperature

International Nuclear Information System (INIS)

Mizutani, Yoshinobu; Ito, Tetsuo; Okamoto, Tatsuki; Kumazawa, Ryoji; Aizawa, Rie; Moriyama, Hideshige

2000-01-01

It is thought that ceramic insulator can be applied to electric power equipments that are under high temperature not to be able use organic materials. Our research has suggested components of mica-alumina combined insulation. As the results of and carried out temperature accelerating test, combined insulation life is expected long term over 40 years at over 500-Celsius degrees. However to construct high reliable insulating system, it is clarified deterioration mechanism on combined insulation and evaluates life of that. Therefore we carried out metal behavior test and voltage aging test using mica-sheet and alumina-cloth that are components of combined insulation under high temperature in nitrogen gas atmosphere. It is cleared two metal behavior mechanisms: One is that the opening of insulator are filled up with copper that is oxidized, the other is the metal diffuses in alumina-cloth through surface. And distance of metal behavior is able to be estimated at modulate temperature and in modulate time. It is also cleared that alumina-cloth is deteriorated by metal behavior into alumina-cloth. These results indicate that combined insulation is deteriorated from electrode side by metal behavior and is finally broken down through alumina-cloth. (author)

Automated jitter correction for IR image processing to assess the quality of W7-X high heat flux components

International Nuclear Information System (INIS)

Greuner, H; De Marne, P; Herrmann, A; Boeswirth, B; Schindler, T; Smirnow, M

2009-01-01

An automated IR image processing method was developed to evaluate the surface temperature distribution of cyclically loaded high heat flux (HHF) plasma facing components. IPP Garching will perform the HHF testing of a high percentage of the series production of the WENDELSTEIN 7-X (W7-X) divertor targets to minimize the number of undiscovered uncertainties in the finally installed components. The HHF tests will be performed as quality assurance (QA) complementary to the non-destructive examination (NDE) methods used during the manufacturing. The IR analysis of an HHF-loaded component detects growing debonding of the plasma facing material, made of carbon fibre composite (CFC), after a few thermal cycles. In the case of the prototype testing, the IR data was processed manually. However, a QA method requires a reliable, reproducible and efficient automated procedure. Using the example of the HHF testing of W7-X pre-series target elements, the paper describes the developed automated IR image processing method. The algorithm is based on an iterative two-step correlation analysis with an individually defined reference pattern for the determination of the jitter.

PREP KITT, System Reliability by Fault Tree Analysis. PREP, Min Path Set and Min Cut Set for Fault Tree Analysis, Monte-Carlo Method. KITT, Component and System Reliability Information from Kinetic Fault Tree Theory

International Nuclear Information System (INIS)

Vesely, W.E.; Narum, R.E.

1997-01-01

1 - Description of problem or function: The PREP/KITT computer program package obtains system reliability information from a system fault tree. The PREP program finds the minimal cut sets and/or the minimal path sets of the system fault tree. (A minimal cut set is a smallest set of components such that if all the components are simultaneously failed the system is failed. A minimal path set is a smallest set of components such that if all of the components are simultaneously functioning the system is functioning.) The KITT programs determine reliability information for the components of each minimal cut or path set, for each minimal cut or path set, and for the system. Exact, time-dependent reliability information is determined for each component and for each minimal cut set or path set. For the system, reliability results are obtained by upper bound approximations or by a bracketing procedure in which various upper and lower bounds may be obtained as close to one another as desired. The KITT programs can handle independent components which are non-repairable or which have a constant repair time. Any assortment of non-repairable components and components having constant repair times can be considered. Any inhibit conditions having constant probabilities of occurrence can be handled. The failure intensity of each component is assumed to be constant with respect to time. The KITT2 program can also handle components which during different time intervals, called phases, may have different reliability properties. 2 - Method of solution: The PREP program obtains minimal cut sets by either direct deterministic testing or by an efficient Monte Carlo algorithm. The minimal path sets are obtained using the Monte Carlo algorithm. The reliability information is obtained by the KITT programs from numerical solution of the simple integral balance equations of kinetic tree theory. 3 - Restrictions on the complexity of the problem: The PREP program will obtain the minimal cut and

Development of a highly reliable CRT processor

International Nuclear Information System (INIS)

Shimizu, Tomoya; Saiki, Akira; Hirai, Kenji; Jota, Masayoshi; Fujii, Mikiya

1996-01-01

Although CRT processors have been employed by the main control board to reduce the operator's workload during monitoring, the control systems are still operated by hardware switches. For further advancement, direct controller operation through a display device is expected. A CRT processor providing direct controller operation must be as reliable as the hardware switches are. The authors are developing a new type of highly reliable CRT processor that enables direct controller operations. In this paper, we discuss the design principles behind a highly reliable CRT processor. The principles are defined by studies of software reliability and of the functional reliability of the monitoring and operation systems. The functional configuration of an advanced CRT processor is also addressed. (author)

High temperature materials; Materiaux a hautes temperatures

Energy Technology Data Exchange (ETDEWEB)

NONE

2003-07-01

The aim of this workshop is to share the needs of high temperature and nuclear fuel materials for future nuclear systems, to take stock of the status of researches in this domain and to propose some cooperation works between the different research organisations. The future nuclear systems are the very high temperature (850 to 1200 deg. C) gas cooled reactors (GCR) and the molten salt reactors (MSR). These systems include not only the reactor but also the fabrication and reprocessing of the spent fuel. This document brings together the transparencies of 13 communications among the 25 given at the workshop: 1) characteristics and needs of future systems: specifications, materials and fuel needs for fast spectrum GCR and very high temperature GCR; 2) high temperature materials out of neutron flux: thermal barriers: materials, resistance, lifetimes; nickel-base metal alloys: status of knowledge, mechanical behaviour, possible applications; corrosion linked with the gas coolant: knowledge and problems to be solved; super-alloys for turbines: alloys for blades and discs; corrosion linked with MSR: knowledge and problems to be solved; 3) materials for reactor core structure: nuclear graphite and carbon; fuel assembly structure materials of the GCR with fast neutron spectrum: status of knowledge and ceramics and cermets needs; silicon carbide as fuel confinement material, study of irradiation induced defects; migration of fission products, I and Cs in SiC; 4) materials for hydrogen production: status of the knowledge and needs for the thermochemical cycle; 5) technologies: GCR components and the associated material needs: compact exchangers, pumps, turbines; MSR components: valves, exchangers, pumps. (J.S.)

Status of design code work for metallic high temperature components

International Nuclear Information System (INIS)

Bieniussa, K.; Seehafer, H.J.; Over, H.H.; Hughes, P.

1984-01-01

The mechanical components of high temperature gas-cooled reactors, HTGR, are exposed to temperatures up to about 1000 deg. C and this in a more or less corrosive gas environment. Under these conditions metallic structural materials show a time-dependent structural behavior. Furthermore changes in the structure of the material and loss of material in the surface can result. The structural material of the components will be stressed originating from load-controlled quantities, for example pressure or dead weight, and/or deformation-controlled quantities, for example thermal expansion or temperature distribution, and thus it can suffer rowing permanent strains and deformations and an exhaustion of the material (damage) both followed by failure. To avoid a failure of the components the design requires the consideration of the following structural failure modes: ductile rupture due to short-term loadings; creep rupture due to long-term loadings; reep-fatigue failure due to cyclic loadings excessive strains due to incremental deformation or creep ratcheting; loss of function due to excessive deformations; loss of stability due to short-term loadings; loss of stability due to long-term loadings; environmentally caused material failure (excessive corrosion); fast fracture due to instable crack growth

Platform for high temperature materials (PHiTEM)

International Nuclear Information System (INIS)

Baluc, N.; Hoffelner, W.; Michler, J.

2007-01-01

Advanced energy power systems like Generation IV fission reactors, thermonuclear fusion reactors, solar thermal/solar chemical reactors, gas turbines and coal gasification systems require materials that can operate at high temperatures in extreme environments: irradiation, corrosion, unidirectional and cyclic loads. On the path to development of new and adequate high temperature materials, understanding of damage formation and evolution and of damage effects is indispensable. Damage of materials in components takes place on different time and length scales. Component failure is usually a macroscopic event. Macroscopic material properties and their changes with time (e.g., hardening, creep embrittlement, corrosion) are determined by the micro- to nano-properties of the material. The multi scale is an ambitious and challenging attempt to take these facts into consideration by developing an unified model of the material behaviour. This requires, however, dedicated tools to test and analyse materials on different scales. The platform for high temperatures materials is being set up within the framework of collaboration between the EPFL, the PSI and the EMPA. It has three main goals: 1) Establish a platform that allows the multi scale characterization of relationships between microstructure and mechanical properties of advanced, high temperature materials, with a focus on irradiated, i.e. radioactive, materials, by combining the use of a focused ion beam and a nano indentation device with multi scale modelling and simulations. 2) Use the methods developed and the results gained for existing materials for developing improved high temperature materials to be used in advanced and sustainable future energy power plants. 3) Become an attractive partner for industry by providing a wide knowledge base, flexibility in answering technical questions and skills to better understand damage in already existing plants and to support development of new products at the industrial scale

Materials requirements for the ITER vacuum vessel and in-vessel components - approaching the construction phase

International Nuclear Information System (INIS)

Barabash, V.; Ioki, K.; Pick, M.; Girard, J.P.; Merola, M.

2007-01-01

Full text of publication follows: The ITER activities are fully devoted toward its construction. In accordance with the ITER integrated project schedule, the procurement specifications for the manufacturing of the Vacuum Vessel should be prepared by March 2008 and the procurement specifications for the in-vessel components (first wall/blanket, divertor) by 2009. To update the design, considering design and technology evolution, the ITER Design Review has been launched. Among the various topics being discussed are the important issues related to selection of materials, material procurement, and assessment of performance during operation. The main requirements related to materials for the vacuum vessel and the in-vessel components are summarized in the paper. The specific licensing requirements are to be followed for structural materials of pressure and nuclear pressure equipment components for construction of ITER. In addition, the procurements in ITER will be done mostly 'in-kind' and it is assumed that materials for these components will be produced by different Parties. However, in accordance with the regulatory requirements and quality requirements for operation, common specifications and the general rules to fulfill these requirements are to be adopted. For some ITER components (e.g. first wall, divertor high heat flux components), the ultimate qualification of the joining technologies (Be/Cu, SS/Cu, CFC/Cu, W/Cu) is under final evaluation. Successful accomplishment of the qualification program will allow to proceed with procurements of the components for ITER. The criteria for acceptance of these components and materials after manufacturing are described and the main results will be reported. Additional materials issues, which come from the on-going manufacturing R and D program, will be also described. Finally, further materials activity during the construction phase, needs for final qualification and acceptance of materials are discussed. (authors)

Reliability in automotive and mechanical engineering determination of component and system reliability

CERN Document Server

Bertsche, Bernd

2008-01-01

In the present contemporary climate of global competition in every branch of engineering and manufacture it has been shown from extensive customer surveys that above every other attribute, reliability stands as the most desired feature in a finished product. To survive this relentless fight for survival any organisation, which neglect the plea of attaining to excellence in reliability, will do so at a serious cost Reliability in Automotive and Mechanical Engineering draws together a wide spectrum of diverse and relevant applications and analyses on reliability engineering. This is distilled into this attractive and well documented volume and practising engineers are challenged with the formidable task of simultaneously improving reliability and reducing the costs and down-time due to maintenance. The volume brings together eleven chapters to highlight the importance of the interrelated reliability and maintenance disciplines. They represent the development trends and progress resulting in making this book ess...

Developing Ultra Reliable Life Support for the Moon and Mars

Science.gov (United States)

Jones, Harry W.

2009-01-01

Recycling life support systems can achieve ultra reliability by using spares to replace failed components. The added mass for spares is approximately equal to the original system mass, provided the original system reliability is not very low. Acceptable reliability can be achieved for the space shuttle and space station by preventive maintenance and by replacing failed units, However, this maintenance and repair depends on a logistics supply chain that provides the needed spares. The Mars mission must take all the needed spares at launch. The Mars mission also must achieve ultra reliability, a very low failure rate per hour, since it requires years rather than weeks and cannot be cut short if a failure occurs. Also, the Mars mission has a much higher mass launch cost per kilogram than shuttle or station. Achieving ultra reliable space life support with acceptable mass will require a well-planned and extensive development effort. Analysis must define the reliability requirement and allocate it to subsystems and components. Technologies, components, and materials must be designed and selected for high reliability. Extensive testing is needed to ascertain very low failure rates. Systems design should segregate the failure causes in the smallest, most easily replaceable parts. The systems must be designed, produced, integrated, and tested without impairing system reliability. Maintenance and failed unit replacement should not introduce any additional probability of failure. The overall system must be tested sufficiently to identify any design errors. A program to develop ultra reliable space life support systems with acceptable mass must start soon if it is to produce timely results for the moon and Mars.

Reliability study of nuclear power stations

International Nuclear Information System (INIS)

Nemec, J.; Sedlacek, J.

1975-01-01

The paper considers the physical and mathematical bases underlying nuclear power station reliability from the standpoints of material fatigue, thermal yield and ageing. The risk of failure of nuclear power station components is determined by means of the Markov stochastic process

Reliability of hydroelectric generation components, systems and units; Confiabilidad de componentes, sistemas y unidades de generacion hidroelectrica

Energy Technology Data Exchange (ETDEWEB)

Sanchez Sanchez, Ramon; Torres Toledano, Gerardo; Franco Nava, Jose Manuel [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1996-12-31

This article presents a methodology for the calculation of the reliability of components, systems and hydroelectric generating units, as well as the scope of a computational system for the evaluation of such reliability. In the case of the reliability calculation of components and systems, the computer programs is not limited to hydro stations and can be used in other type of systems. [Espanol] En este articulo se presenta una metodologia para calcular la confiabilidad de componentes, sistemas y unidades de generacion hidroelectrica, asi como el alcance de un sistema computacional para evaluar dicha confiabilidad. En el caso del calculo de confiabilidad de componentes y sistemas, el programa de computo no se limita a centrales hidroelectricas y puede utilizarse en otro tipo de sistemas.

Reliability of hydroelectric generation components, systems and units; Confiabilidad de componentes, sistemas y unidades de generacion hidroelectrica

Energy Technology Data Exchange (ETDEWEB)

Sanchez Sanchez, Ramon; Torres Toledano, Gerardo; Franco Nava, Jose Manuel [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

1997-12-31

This article presents a methodology for the calculation of the reliability of components, systems and hydroelectric generating units, as well as the scope of a computational system for the evaluation of such reliability. In the case of the reliability calculation of components and systems, the computer programs is not limited to hydro stations and can be used in other type of systems. [Espanol] En este articulo se presenta una metodologia para calcular la confiabilidad de componentes, sistemas y unidades de generacion hidroelectrica, asi como el alcance de un sistema computacional para evaluar dicha confiabilidad. En el caso del calculo de confiabilidad de componentes y sistemas, el programa de computo no se limita a centrales hidroelectricas y puede utilizarse en otro tipo de sistemas.

Reliability demonstration test for load-sharing systems with exponential and Weibull components.

Directory of Open Access Journals (Sweden)

Jianyu Xu

Full Text Available Conducting a Reliability Demonstration Test (RDT is a crucial step in production. Products are tested under certain schemes to demonstrate whether their reliability indices reach pre-specified thresholds. Test schemes for RDT have been studied in different situations, e.g., lifetime testing, degradation testing and accelerated testing. Systems designed with several structures are also investigated in many RDT plans. Despite the availability of a range of test plans for different systems, RDT planning for load-sharing systems hasn't yet received the attention it deserves. In this paper, we propose a demonstration method for two specific types of load-sharing systems with components subject to two distributions: exponential and Weibull. Based on the assumptions and interpretations made in several previous works on such load-sharing systems, we set the mean time to failure (MTTF of the total system as the demonstration target. We represent the MTTF as a summation of mean time between successive component failures. Next, we introduce generalized test statistics for both the underlying distributions. Finally, RDT plans for the two types of systems are established on the basis of these test statistics.

In-plant reliability data base for nuclear power plant components: data collection and methodology report

International Nuclear Information System (INIS)

Drago, J.P.; Borkowski, R.J.; Pike, D.H.; Goldberg, F.F.

1982-07-01

The development of a component reliability data for use in nuclear power plant probabilistic risk assessments and reliabiilty studies is presented in this report. The sources of the data are the in-plant maintenance work request records from a sample of nuclear power plants. This data base is called the In-Plant Reliability Data (IPRD) system. Features of the IPRD system are compared with other data sources such as the Licensee Event Report system, the Nuclear Plant Reliability Data system, and IEEE Standard 500. Generic descriptions of nuclear power plant systems formulated for IPRD are given

Design Protocols and Analytical Strategies that Incorporate Structural Reliability Models

Science.gov (United States)

Duffy, Stephen F.

1997-01-01

Al single crystal turbine blade material; map a simplistic failure strength envelope of the material; develop a statistically based reliability computer algorithm, verify the reliability model and computer algorithm, and model stator vanes for rig tests. Thus establishing design protocols that enable the engineer to analyze and predict the mechanical behavior of ceramic composites and intermetallics would mitigate the prototype (trial and error) approach currently used by the engineering community. The primary objective of the research effort supported by this short term grant is the continued creation of enabling technologies for the macroanalysis of components fabricated from ceramic composites and intermetallic material systems. The creation of enabling technologies aids in shortening the product development cycle of components fabricated from the new high technology materials.

Research on Evaluation Methodology for High Temperature Components and Technical Issues

International Nuclear Information System (INIS)

Kim, Y.J.; Han, S.B.

2007-03-01

The research on evaluation methodology for high temperature components and technical issues includes the comparison of evaluation technology of Very High Temperature Reactors(VHTRs) with that of present commercial reactors, the review of Hot Gas Duct(HGD) insulation designs, the analysis of the codes related to VHTR component construction and the analysis of technical issues on application of present codes to HGD construction. Codes to assure the integrity of the VHTR components are not fully prepared yet in any country. To understand the evaluation technology of the VHTR-related codes, key requirements of ASME B and PV Code Section III, Subsection NB and NH were compared. Six kinds of HGD designs were reviewed and compared. A reference which analyzed seven kinds of present component codes were reviewed and the limitations of them were summarized. Especially it was found that the selection of materials is limited, material property data are not enough, and design analysis methodology is not fully specified

Heavy Vehicle Propulsion System Materials Program semiannual progress report for October 1996 through March 1997

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-07-01

The purpose of the Heavy Vehicle Propulsion System Materials Program is the development of materials: ceramics, intermetallics, metal alloys, and metal and ceramic coatings, to support the dieselization of class 1-3 trucks to realize a 35% fuel-economy improvement over current gasoline-fueled trucks and to support commercialization of fuel-flexible LE-55 low-emissions, high-efficiency diesel engines for class 7-8 trucks. The design of advanced components for high-efficiency diesel engines has, in some cases, pushed the performance envelope for materials of construction past the point of reliable operation. Higher mechanical and tribological stresses and higher temperatures of advanced designs limit the engine designers; advanced materials allow the design of components that may operate reliably at higher stresses and temperatures, thus enabling more efficient engine designs. Advanced materials also offer the opportunity to improve the emissions, NVH, and performance of diesel engines for pickup trucks, vans, and sport utility vehicles. The principal areas of research are: (1) cost effective high performance materials and processing; (2) advanced manufacturing technology; (3) testing and characterization; and (4) materials and testing standards.

Dependent systems reliability estimation by structural reliability approach

DEFF Research Database (Denmark)

Kostandyan, Erik; Sørensen, John Dalsgaard

2014-01-01

Estimation of system reliability by classical system reliability methods generally assumes that the components are statistically independent, thus limiting its applicability in many practical situations. A method is proposed for estimation of the system reliability with dependent components, where...... the leading failure mechanism(s) is described by physics of failure model(s). The proposed method is based on structural reliability techniques and accounts for both statistical and failure effect correlations. It is assumed that failure of any component is due to increasing damage (fatigue phenomena...... identification. Application of the proposed method can be found in many real world systems....

Materials Innovation for Next-Generation T&D Grid Components. Workshop Summary Report

Energy Technology Data Exchange (ETDEWEB)

Taylor, Emmanuel [Energetics Incorporated, Columbia, MD (United States); Kramer, Caroline [Energetics Incorporated, Columbia, MD (United States); Marchionini, Brian [Energetics Incorporated, Columbia, MD (United States); Sabouni, Ridah [Energetics Incorporated, Columbia, MD (United States); Cheung, Kerry [U.S. Department of Energy (DOE), Washington, DC (United States). Office of Electricity Delivery and Energy Reliability (OE); Lee, Dominic F [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2015-10-01

The Materials Innovations for Next-Generation T&D Grid Components Workshop was co-sponsored by the U.S. Department of Energy (DOE) Office of Electricity Delivery and Energy Reliability and the Oak Ridge National Laboratory (ORNL) and held on August 26 27, 2015, at the ORNL campus in Oak Ridge, Tennessee. The workshop was planned and executed under the direction of workshop co-chair Dr. Kerry Cheung (DOE) and co-chair Dr. Dominic Lee (ORNL). The information contained herein is based on the results of the workshop, which was attended by nearly 50 experts from government, industry, and academia. The research needs and pathways described in this report reflect the expert opinions of workshop participants, but they are not intended to represent the views of the entire electric power community.

Toward reliable and repeatable automated STEM-EDS metrology with high throughput

Science.gov (United States)

Zhong, Zhenxin; Donald, Jason; Dutrow, Gavin; Roller, Justin; Ugurlu, Ozan; Verheijen, Martin; Bidiuk, Oleksii

2018-03-01

New materials and designs in complex 3D architectures in logic and memory devices have raised complexity in S/TEM metrology. In this paper, we report about a newly developed, automated, scanning transmission electron microscopy (STEM) based, energy dispersive X-ray spectroscopy (STEM-EDS) metrology method that addresses these challenges. Different methodologies toward repeatable and efficient, automated STEM-EDS metrology with high throughput are presented: we introduce the best known auto-EDS acquisition and quantification methods for robust and reliable metrology and present how electron exposure dose impacts the EDS metrology reproducibility, either due to poor signalto-noise ratio (SNR) at low dose or due to sample modifications at high dose conditions. Finally, we discuss the limitations of the STEM-EDS metrology technique and propose strategies to optimize the process both in terms of throughput and metrology reliability.

Forecast of reliability for mechanical components subjected to wearing; Pronostico de la fiabilidad de componentes mecanicos sometidos a desgaste

Energy Technology Data Exchange (ETDEWEB)

Angulo-Zevallos, J.; Castellote-Varona, C.; Alanbari, M.

2010-07-01

Generally, improving quality and price of products, obtaining a complete customer satisfaction and achieving excellence in all the processes are some of the challenges currently set up by every company. To do this, knowing frequently the reliability of some component is necessary. To achieve this goal, a research, that contributes with clear ideas and offers a methodology for the assessment of the parameters involved in the reliability calculation, becomes necessary. A parameter closely related to this concept is the probability of product failure depending on the operating time. It is known that mechanical components fail by: creep, fatigue, wear, corrosion, etc. This article proposes a methodology for finding the reliability of a component subject to wear, such as brake pads, grinding wheels, brake linings of clutch discs, etc. (Author)

High-Capacity, High-Voltage Composite Oxide Cathode Materials

Science.gov (United States)

Hagh, Nader M.

2015-01-01

This SBIR project integrates theoretical and experimental work to enable a new generation of high-capacity, high-voltage cathode materials that will lead to high-performance, robust energy storage systems. At low operating temperatures, commercially available electrode materials for lithium-ion (Li-ion) batteries do not meet energy and power requirements for NASA's planned exploration activities. NEI Corporation, in partnership with the University of California, San Diego, has developed layered composite cathode materials that increase power and energy densities at temperatures as low as 0 degC and considerably reduce the overall volume and weight of battery packs. In Phase I of the project, through innovations in the structure and morphology of composite electrode particles, the partners successfully demonstrated an energy density exceeding 1,000 Wh/kg at 4 V at room temperature. In Phase II, the team enhanced the kinetics of Li-ion transport and electronic conductivity at 0 degC. An important feature of the composite cathode is that it has at least two components that are structurally integrated. The layered material is electrochemically inactive; however, upon structural integration with a spinel material, the layered material can be electrochemically activated and deliver a large amount of energy with stable cycling.

Assessment and selection of materials for ITER in-vessel components

Science.gov (United States)

Kalinin, G.; Barabash, V.; Cardella, A.; Dietz, J.; Ioki, K.; Matera, R.; Santoro, R. T.; Tivey, R.; ITER Home Teams

2000-12-01

During the international thermonuclear experimental reactor (ITER) engineering design activities (EDA) significant progress has been made in the selection of materials for the in-vessel components of the reactor. This progress is a result of the worldwide collaboration of material scientists and industries which focused their effort on the optimisation of material and component manufacturing and on the investigation of the most critical material properties. Austenitic stainless steels 316L(N)-IG and 316L, nickel-based alloys Inconel 718 and Inconel 625, Ti-6Al-4V alloy and two copper alloys, CuCrZr-IG and CuAl25-IG, have been proposed as reference structural materials, and ferritic steel 430, and austenitic steel 304B7 with the addition of boron have been selected for some specific parts of the ITER in-vessel components. Beryllium, tungsten and carbon fibre composites are considered as plasma facing armour materials. The data base on the properties of all these materials is critically assessed and briefly reviewed in this paper together with the justification of the material selection (e.g., effect of neutron irradiation on the mechanical properties of materials, effect of manufacturing cycle, etc.).

Utilizing clad piping to improve process plant piping integrity, reliability, and operations

International Nuclear Information System (INIS)

Chakravarti, B.

1996-01-01

During the past four years carbon steel piping clad with type 304L (UNS S30403) stainless steel has been used to solve the flow accelerated corrosion (FAC) problem in nuclear power plants with exceptional success. The product is designed to allow ''like for like'' replacement of damaged carbon steel components where the carbon steel remains the pressure boundary and type 304L (UNS S30403) stainless steel the corrosion allowance. More than 3000 feet of piping and 500 fittings in sizes from 6 to 36-in. NPS have been installed in the extraction steam and other lines of these power plants to improve reliability, eliminate inspection program, reduce O and M costs and provide operational benefits. This concept of utilizing clad piping in solving various corrosion problems in industrial and process plants by conservatively selecting a high alloy material as cladding can provide similar, significant benefits in controlling corrosion problems, minimizing maintenance cost, improving operation and reliability to control performance and risks in a highly cost effective manner. This paper will present various material combinations and applications that appear ideally suited for use of the clad piping components in process plants

Embedded Sensors and Controls to Improve Component Performance and Reliability: Conceptual Design Report

Energy Technology Data Exchange (ETDEWEB)

Kisner, Roger A [ORNL; Melin, Alexander M [ORNL; Burress, Timothy A [ORNL; Fugate, David L [ORNL; Holcomb, David Eugene [ORNL; Wilgen, John B [ORNL; Miller, John M [ORNL; Wilson, Dane F [ORNL; Silva, Pamela C [ORNL; Whitlow, Lynsie J [ORNL; Peretz, Fred J [ORNL

2012-10-01

The overall project objective is to demonstrate improved reliability and increased performance made possible by deeply embedding instrumentation and controls (I&C) in nuclear power plant components. The project is employing a highly instrumented canned rotor, magnetic bearing, fluoride salt pump as its I&C technology demonstration vehicle. The project s focus is not primarily on pump design, but instead is on methods to deeply embed I&C within a pump system. However, because the I&C is intimately part of the basic millisecond-by-millisecond functioning of the pump, the I&C design cannot proceed in isolation from the other aspects of the pump. The pump will not function if the characteristics of the I&C are not embedded within the design because the I&C enables performance of the basic function rather than merely monitoring quasi-stable performance. Traditionally, I&C has been incorporated in nuclear power plant (NPP) components after their design is nearly complete; adequate performance was obtained through over-design. This report describes the progress and status of the project and provides a conceptual design overview for the embedded I&C pump.

Experimental High Speed Milling of the Selected Thin-Walled Component

Directory of Open Access Journals (Sweden)

Jozef Zajac

2017-11-01

Full Text Available In a technical practice, it is possible to meet thin-walled parts more and more often. These parts are most commonly used in the automotive industry or aircraft industry to reduce the weight of different design part of cars or aircraft. Presented article is focused on experimental high speed milling of selected thin-walled component. The introduction of this article presents description of high speed machining and specification of thin – walled parts. The experiments were carried out using a CNC machine Pinnacle VMC 650S and C45 material - plain carbon steel for automotive components and mechanical engineering. In the last part of the article, described are the arrangements to reduction of deformation of thin-walled component during the experimental high speed milling.

Reliability and risk functions for structural components taking into account inspection results

International Nuclear Information System (INIS)

Rackwitz, R.; Schall, G.

1989-01-01

The method of outcrossings has been shown to be efficient when calculating the failure probability of metallic structural components under ergodic Gaussian loading. Using Paris/Erdogan's crack growth law it is possible to develop a semi-analytical calculation model for both the reliability and the risk function. For numerical studies an approximate method of asymptotic nature is proposed. The same methodology also enables to incorporate inspection observations. (orig.) [de

Development of reliability database for safety-related I and C component based on operating experience of KSNP

International Nuclear Information System (INIS)

Jang, S. C.; Han, S. H.; Min, K. R.

2001-01-01

Reliability database for safety-related I and C components has been developed, based on domestic operating experience of total 8.63 years from four units-Yonggwang Units 3 and 4, and Ulchin Units 3 and 4. This plant-specific data of safety-related I and C components has compared with operating experience for CE-supplied plants in U.S.A. As a results, we found that on the whole the domestic reliability data was similar to CE-supplied plants in USA, through lots of failures occurred early in the commercial operation were included in our analyses without percolation

High capacity anode materials for lithium ion batteries

Science.gov (United States)

Lopez, Herman A.; Anguchamy, Yogesh Kumar; Deng, Haixia; Han, Yongbon; Masarapu, Charan; Venkatachalam, Subramanian; Kumar, Suject

2015-11-19

High capacity silicon based anode active materials are described for lithium ion batteries. These materials are shown to be effective in combination with high capacity lithium rich cathode active materials. Supplemental lithium is shown to improve the cycling performance and reduce irreversible capacity loss for at least certain silicon based active materials. In particular silicon based active materials can be formed in composites with electrically conductive coatings, such as pyrolytic carbon coatings or metal coatings, and composites can also be formed with other electrically conductive carbon components, such as carbon nanofibers and carbon nanoparticles. Additional alloys with silicon are explored.

Additive Manufacturing of Multifunctional Components Using High Density Carbon Nanotube Yarn Filaments

Science.gov (United States)

Gardner, John M.; Sauti, Godfrey; Kim, Jae-Woo; Cano, Roberto J.; Wincheski, Russell A.; Stelter, Christopher J.; Grimsley, Brian W.; Working, Dennis C.; Siochi, Emilie J.

2016-01-01

Additive manufacturing allows for design freedom and part complexity not currently attainable using traditional manufacturing technologies. Fused Filament Fabrication (FFF), for example, can yield novel component geometries and functionalities because the method provides a high level of control over material placement and processing conditions. This is achievable by extrusion of a preprocessed filament feedstock material along a predetermined path. However if fabrication of a multifunctional part relies only on conventional filament materials, it will require a different material for each unique functionality printed into the part. Carbon nanotubes (CNTs) are an attractive material for many applications due to their high specific strength as well as good electrical and thermal conductivity. The presence of this set of properties in a single material presents an opportunity to use one material to achieve multifunctionality in an additively manufactured part. This paper describes a recently developed method for processing continuous CNT yarn filaments into three-dimensional articles, and summarizes the mechanical, electrical, and sensing performance of the components fabricated in this way.

Reliability of reactor materials

International Nuclear Information System (INIS)

Toerroenen, K.; Aho-Mantila, I.

1986-05-01

This report is the final technical report of the fracture mechanics part of the Reliability of Reactor Materials Programme, which was carried out at the Technical Research Centre of Finland (VTT) through the years 1981 to 1983. Research and development work was carried out in five major areas, viz. statistical treatment and modelling of cleavage fracture, crack arrest, ductile fracture, instrumented impact testing as well as comparison of numerical and experimental elastic-plastic fracture mechanics. In the area of cleavage fracture the critical variables affecting the fracture of steels are considered in the frames of a statistical model, so called WST-model. Comparison of fracture toughness values predicted by the model and corresponding experimental values shows excellent agreement for a variety of microstructures. different posibilities for using the model are discussed. The development work in the area of crack arrest testing was concentrated in the crack starter properties, test arrangement and computer control. A computerized elastic-plastic fracture testing method with a variety of test specimen geometries in a large temperature range was developed for a routine stage. Ductile fracture characteristics of reactor pressure vessel steel A533B and comparable weld material are given. The features of a new, patented instrumented impact tester are described. Experimental and theoretical comparisons between the new and conventional testers indicated clearly the improvements achieved with the new tester. A comparison of numerical and experimental elastic-plastic fracture mechanics capabilities at VTT was carried out. The comparison consisted of two-dimensional linear elastic as well as elastic-plastic finite element analysis of four specimen geometries and equivalent experimental tests. (author)

Towards a more consolidated approach to material data management in life assessment of power plant components

Energy Technology Data Exchange (ETDEWEB)

Jovanovic, A; Maile, K [MPA Stuttgart (Germany)

1999-12-31

The presentation discusses the necessity of having a more consolidated (unified, possibly `European`) framework for all (not only pure experimental) material data needed for optimized life management and assessment of high-temperature and other components in power and process plants. After setting the main requirements for such a system, a description of efforts done in this direction at MPA Stuttgart in the area of high-temperature components in power plants is given. Furthermore, a reference to other relevant efforts elsewhere is made and an example of practical application of the proposed solution described (optimized material selection and life assessment of high-temperature piping). (orig.) 10 refs.

Towards a more consolidated approach to material data management in life assessment of power plant components

Energy Technology Data Exchange (ETDEWEB)

Jovanovic, A.; Maile, K. [MPA Stuttgart (Germany)

1998-12-31

The presentation discusses the necessity of having a more consolidated (unified, possibly `European`) framework for all (not only pure experimental) material data needed for optimized life management and assessment of high-temperature and other components in power and process plants. After setting the main requirements for such a system, a description of efforts done in this direction at MPA Stuttgart in the area of high-temperature components in power plants is given. Furthermore, a reference to other relevant efforts elsewhere is made and an example of practical application of the proposed solution described (optimized material selection and life assessment of high-temperature piping). (orig.) 10 refs.

Nondestructive examination (NDE) reliability for inservice inspection of light water reactors

International Nuclear Information System (INIS)

Doctor, S.R.; Deffenbaugh, J.D.; Good, M.S.; Green, E.R.; Heasler, P.G.; Simonen, F.A.; Spanner, J.C.; Taylor, T.T.

1989-10-01

The Evaluation and Improvement of NDE Reliability for Inservice Inspection of Light Water Reactors (NDE Reliability) Program at the Pacific Northwest Laboratory was established by the Nuclear Regulatory Commission to determine the reliability of current inservice inspection (ISI) techniques and to develop recommendations that will ensure a suitably high inspection reliability. The objectives of this program include determining the reliability of ISI performed on the primary systems of commercial light-water reactors (LWRs); using probabilistic fracture mechanics analysis to determine the impact of NDE unreliability on system safety; and evaluating reliability improvement that can be achieved with improved and advanced technology. A final objective is to formulate recommended revisions to ASME Code and Regulatory requirements based on material properties, service conditions, and NDE capabilities and uncertainties. The program scope is limited to ISI of the primary systems including the piping, vessel, and other inspected components. This is a progress report covering the programmatic work from October 1987 through March 1988. 21 refs., 28 figs., 2 tabs

Nondestructive examination (NDE) reliability for inservice inspection of light waters reactors

International Nuclear Information System (INIS)

Doctor, S.R.; Deffenbaugh, J.D.; Good, M.S.; Green, E.R.; Heasler, P.G.; Simonen, F.A.; Spanner, J.C.; Taylor, T.T.

1989-11-01

Evaluation and Improvement of NDE Reliability for Inservice Inspection of Light Water Reactors (NDE Reliability) Program at the Pacific Northwest Laboratory was established by the Nuclear Regulatory Commission to determine the reliability of current inservice inspection (ISI) techniques and to develop recommendations that will ensure a suitably high inspection reliability. The objectives of this program include determining the reliability of ISI performed on the primary systems of commercial light-water reactors (LWRs); using probabilistic fracture mechanics analysis to determine the impact of NDE unreliability on system safety; and evaluating reliability improvements that can be achieved with improved and advanced technology. A final objective is to formulate recommended revisions to ASME Code and Regulatory requirements, based on material properties, service conditions, and NDE uncertainties. The program scope is limited to ISI of the primary systems including the piping, vessel, and other inspected components. This is a progress report covering the programmatic work from April 1988 through September 1988. 33 refs., 70 figs., 12 tabs

Nondestructive Examination (NDE) Reliability for Inservice Inspection of Light Water Reactors

International Nuclear Information System (INIS)

Doctor, S.R.; Diaz, A.A.; Friley, J.R.

1993-09-01

The Evaluation and Improvement of NDE Reliability for Inservice Inspection of Light Water Reactors (NDE Reliability) Program at the Pacific Northwest Laboratory was established by the Nuclear Regulatory Commission to determine the reliability of current inservice inspection (ISI) techniques and to develop recommendations that will ensure a suitably high inspection reliability. The objectives of this program include determining the reliability of ISI performed on the primary systems of commercial light-water reactors (LWRs); using probabilistic fracture mechanics analysis to determine the impact of NDE unreliability on system safety; and evaluating reliability improvements that can be achieved with improved and advanced technology. A final objective is to formulate recommended revisions to ASME Code and Regulatory requirements, based on material properties, service conditions, and NDE uncertainties. The program scope is limited to ISI of the primary systems including the piping, vessel, and other components inspected in accordance with Section XI of the ASME Code. This is a progress report covering the programmatic work from October 1991 through March 1992

Computer-aided reliability and risk assessment

International Nuclear Information System (INIS)

Leicht, R.; Wingender, H.J.

1989-01-01

Activities in the fields of reliability and risk analyses have led to the development of particular software tools which now are combined in the PC-based integrated CARARA system. The options available in this system cover a wide range of reliability-oriented tasks, like organizing raw failure data in the component/event data bank FDB, performing statistical analysis of those data with the program FDA, managing the resulting parameters in the reliability data bank RDB, and performing fault tree analysis with the fault tree code FTL or evaluating the risk of toxic or radioactive material release with the STAR code. (orig.)

On the possibility of high-dispersed composite material obtaining in impulsive high-enthalpy flow

International Nuclear Information System (INIS)

Blinkov, I.V.; Brodyagin, A.G.; Ivanov, A.V.

1987-01-01

Thermodynamic possibility for the formation of TiC-Mo composite dispersed material in 1200-2800 K temperature interval and effect of H/Cl, C/Ti relation on the composite material composition are demonstrated. Investigation into the plasmo-chemical process of producing high-dispersed composite material in the pulsed regime has pointed out to a possibility of the product chemical composition regulation by changing the energy, flow-rate parameters and by conditions of component introduction into the plasmochemical reactor. Molybdenum-carbide composition powders produced are characterized by the particle size of ∼ 10 nm and high Mo and TiC distribution steadyness which allows one to exclude the stage of a long-term component mixing under the composition production

Reliability-based optimization of maintenance scheduling of mechanical components under fatigue

Science.gov (United States)

Beaurepaire, P.; Valdebenito, M.A.; Schuëller, G.I.; Jensen, H.A.

2012-01-01

This study presents the optimization of the maintenance scheduling of mechanical components under fatigue loading. The cracks of damaged structures may be detected during non-destructive inspection and subsequently repaired. Fatigue crack initiation and growth show inherent variability, and as well the outcome of inspection activities. The problem is addressed under the framework of reliability based optimization. The initiation and propagation of fatigue cracks are efficiently modeled using cohesive zone elements. The applicability of the method is demonstrated by a numerical example, which involves a plate with two holes subject to alternating stress. PMID:23564979

Probabilistic Material Strength Degradation Model for Inconel 718 Components Subjected to High Temperature, Mechanical Fatigue, Creep and Thermal Fatigue Effects

Science.gov (United States)

Bast, Callie Corinne Scheidt

1994-01-01

This thesis presents the on-going development of methodology for a probabilistic material strength degradation model. The probabilistic model, in the form of a postulated randomized multifactor equation, provides for quantification of uncertainty in the lifetime material strength of aerospace propulsion system components subjected to a number of diverse random effects. This model is embodied in the computer program entitled PROMISS, which can include up to eighteen different effects. Presently, the model includes four effects that typically reduce lifetime strength: high temperature, mechanical fatigue, creep, and thermal fatigue. Statistical analysis was conducted on experimental Inconel 718 data obtained from the open literature. This analysis provided regression parameters for use as the model's empirical material constants, thus calibrating the model specifically for Inconel 718. Model calibration was carried out for four variables, namely, high temperature, mechanical fatigue, creep, and thermal fatigue. Methodology to estimate standard deviations of these material constants for input into the probabilistic material strength model was developed. Using the current version of PROMISS, entitled PROMISS93, a sensitivity study for the combined effects of mechanical fatigue, creep, and thermal fatigue was performed. Results, in the form of cumulative distribution functions, illustrated the sensitivity of lifetime strength to any current value of an effect. In addition, verification studies comparing a combination of mechanical fatigue and high temperature effects by model to the combination by experiment were conducted. Thus, for Inconel 718, the basic model assumption of independence between effects was evaluated. Results from this limited verification study strongly supported this assumption.

Use of reliability engineering in development and manufacturing of metal parts

International Nuclear Information System (INIS)

Khan, A.; Iqbal, M.A.; Asif, M.

2005-01-01

The reliability engineering predicts modes of failures and weak links before the system is built instead of failure case study. The reliability engineering analysis will help in the manufacturing economy, assembly accuracy and qualification by testing, leading to production of metal parts in an aerospace industry. This methodology will also minimize the performance constraints in any requirement for the application of metal components in aerospace systems. The reliability engineering predicts the life of the parts under loading conditions whether dynamic or static. Reliability predictions can help engineers in making decisions about design of components, materials selection and qualification under applied stress levels. Two methods of reliability prediction i.e. Part Stress Analysis and Part Count have been used in this study. In this paper we will discuss how these two methods can be used to measure reliability of a system during development phases, which includes the measuring effect of environmental and operational variables. The equations are used to measure the reliability of each type of component, as well as, integration for measuring system applied for the reliability analysis. (author)

Radiations effects on polymeric materials used in CERN particles accelerators

International Nuclear Information System (INIS)

Tavlet, M.

1997-01-01

For fundamental research on the basis structure of matter, the European Organization for Nuclear Research (CERN) operates several high-energy particle accelerators around which materials and components are exposed to ionizing radiation. To ensure a safe and reliable operation, the radiation behaviour of most of the components is systematically tested prior to their selection. The long-term radiation-test programme allows to assess the component lifetime in the environment or our accelerators where the absorbed doses are continuously recorded. This article presents organic materials in use at CERN, and some recent results are given on their behaviour under irradiation. (authors)

Development of component reliability data for PSA and risk based management in Japan

International Nuclear Information System (INIS)

Yoshihiro Tomioka; Mitsumasa Hirano; Shunsuke Kondo

1997-01-01

The author presents the outline of development of the component reliability data for PSA and risk based management in Japan. In the first part following the introduction, the development process is described. The next part describes issues discussed in the course of the development, which are treatment of zero failure data, error factor, estimation of unavailable failure rate and integral test

Stress relief of ceramic components in high voltage assemblies. Final report

International Nuclear Information System (INIS)

Heinen, R.J.

1979-02-01

Two types of ceramic packages were evaluated to determine the effectiveness of encapsulating the ceramic components in beta eucryptite filled epoxy. The requirements (no high voltage breakdown, no ceramic cracking, and no encapsulant cracking) were met by the spark gap assembly, but the sprytron assembly had cracking in the encapsulant after thermal cycling. The encapsulation of the ceramic component in beta eucryptite filled epoxy with a stress decoupling material selectively applied in the stress concentrated areas were used to prevent cracking in the sprytron encapsulant. This method is proposed as the standard encapsulation process for high voltage ceramic components

Modelling of the high temperature behaviour of metallic materials

International Nuclear Information System (INIS)

Mohr, R.

1999-01-01

The design of components of metallic high-temperature materials by the finite element method requires the application of phenomenological viscoplastic material models. The route from the choice of a convenient model, the numerical integration of the equations and the parameter identification to the design of components is described. The Chaboche-model is used whose evolution equations are explicitly integrated. The parameters are determined by graphical and numerical methods in order to use the material model for describing the deformation behaviour of a chromium steel and an intermetallic titanium aluminide alloy. (orig.)

Reliability and Failure in NASA Missions: Blunders, Normal Accidents, High Reliability, Bad Luck

Science.gov (United States)

Jones, Harry W.

2015-01-01

NASA emphasizes crew safety and system reliability but several unfortunate failures have occurred. The Apollo 1 fire was mistakenly unanticipated. After that tragedy, the Apollo program gave much more attention to safety. The Challenger accident revealed that NASA had neglected safety and that management underestimated the high risk of shuttle. Probabilistic Risk Assessment was adopted to provide more accurate failure probabilities for shuttle and other missions. NASA's "faster, better, cheaper" initiative and government procurement reform led to deliberately dismantling traditional reliability engineering. The Columbia tragedy and Mars mission failures followed. Failures can be attributed to blunders, normal accidents, or bad luck. Achieving high reliability is difficult but possible.

Reliability optimization for series systems under uncertain component failure rates in the design phase

NARCIS (Netherlands)

Ge, Q.; Peng, H.; van Houtum, G.J.J.A.N.; Adan, I.J.B.F.

2018-01-01

We develop an optimization model to determine the reliability design of critical components in a serial system. The system is under a service contract, and a penalty cost has to be paid by the OEM when the total system down time exceeds a predetermined level, which complicates the evaluation of the

Aspects for selection of materials and fabrication processes for nuclear component manufacturing

International Nuclear Information System (INIS)

Pernstich, K.

1980-01-01

For components of the Nuclear steam supply System of Light Water Reactors an extremely high safety standard is required. These requirements only can be met by adequate selection of materials and fabrication processes and their proper application in combination with strict quality assurance and control measurements. A general overview of the basic aspects to be considered in this connection is presented together with an indication of the present state of art for the main materials and fabrication processes. (author) [pt

Assessment of ALWR passive safety system reliability. Phase 1: Methodology development and component failure quantification

International Nuclear Information System (INIS)

Hake, T.M.; Heger, A.S.

1995-04-01

Many advanced light water reactor (ALWR) concepts proposed for the next generation of nuclear power plants rely on passive systems to perform safety functions, rather than active systems as in current reactor designs. These passive systems depend to a great extent on physical processes such as natural circulation for their driving force, and not on active components, such as pumps. An NRC-sponsored study was begun at Sandia National Laboratories to develop and implement a methodology for evaluating ALWR passive system reliability in the context of probabilistic risk assessment (PRA). This report documents the first of three phases of this study, including methodology development, system-level qualitative analysis, and sequence-level component failure quantification. The methodology developed addresses both the component (e.g. valve) failure aspect of passive system failure, and uncertainties in system success criteria arising from uncertainties in the system's underlying physical processes. Traditional PRA methods, such as fault and event tree modeling, are applied to the component failure aspect. Thermal-hydraulic calculations are incorporated into a formal expert judgment process to address uncertainties in selected natural processes and success criteria. The first phase of the program has emphasized the component failure element of passive system reliability, rather than the natural process uncertainties. Although cursory evaluation of the natural processes has been performed as part of Phase 1, detailed assessment of these processes will take place during Phases 2 and 3 of the program

Application of nonparametric statistics to material strength/reliability assessment

International Nuclear Information System (INIS)

Arai, Taketoshi

1992-01-01

An advanced material technology requires data base on a wide variety of material behavior which need to be established experimentally. It may often happen that experiments are practically limited in terms of reproducibility or a range of test parameters. Statistical methods can be applied to understanding uncertainties in such a quantitative manner as required from the reliability point of view. Statistical assessment involves determinations of a most probable value and the maximum and/or minimum value as one-sided or two-sided confidence limit. A scatter of test data can be approximated by a theoretical distribution only if the goodness of fit satisfies a test criterion. Alternatively, nonparametric statistics (NPS) or distribution-free statistics can be applied. Mathematical procedures by NPS are well established for dealing with most reliability problems. They handle only order statistics of a sample. Mathematical formulas and some applications to engineering assessments are described. They include confidence limits of median, population coverage of sample, required minimum number of a sample, and confidence limits of fracture probability. These applications demonstrate that a nonparametric statistical estimation is useful in logical decision making in the case a large uncertainty exists. (author)

Reliability and availability of high power proton accelerators

International Nuclear Information System (INIS)

Cho, Y.

1999-01-01

It has become increasingly important to address the issues of operational reliability and availability of an accelerator complex early in its design and construction phases. In this context, reliability addresses the mean time between failures and the failure rate, and availability takes into account the failure rate as well as the length of time required to repair the failure. Methods to reduce failure rates include reduction of the number of components and over-design of certain key components. Reduction of the on-line repair time can be achieved by judiciously designed hardware, quick-service spare systems and redundancy. In addition, provisions for easy inspection and maintainability are important for both reduction of the failure rate as well as reduction of the time to repair. The radiation safety exposure principle of ALARA (as low as reasonably achievable) is easier to comply with when easy inspection capability and easy maintainability are incorporated into the design. Discussions of past experience in improving accelerator availability, some recent developments, and potential R and D items are presented. (author)

Reliability Issues in Stirling Radioisotope Power Systems

Science.gov (United States)

Schreiber, Jeffrey; Shah, Ashwin

2005-01-01

Stirling power conversion is a potential candidate for use in a Radioisotope Power System (RPS) for space science missions because it offers a multifold increase in the conversion efficiency of heat to electric power and reduced requirement of radioactive material. Reliability of an RPS that utilizes Stirling power conversion technology is important in order to ascertain long term successful performance. Owing to long life time requirement (14 years), it is difficult to perform long-term tests that encompass all the uncertainties involved in the design variables of components and subsystems comprising the RPS. The requirement for uninterrupted performance reliability and related issues are discussed, and some of the critical areas of concern are identified. An overview of the current on-going efforts to understand component life, design variables at the component and system levels, and related sources and nature of uncertainties are also discussed. Current status of the 110 watt Stirling Radioisotope Generator (SRG110) reliability efforts is described. Additionally, an approach showing the use of past experience on other successfully used power systems to develop a reliability plan for the SRG110 design is outlined.

Time domain series system definition and gear set reliability modeling

International Nuclear Information System (INIS)

Xie, Liyang; Wu, Ningxiang; Qian, Wenxue

2016-01-01

Time-dependent multi-configuration is a typical feature for mechanical systems such as gear trains and chain drives. As a series system, a gear train is distinct from a traditional series system, such as a chain, in load transmission path, system-component relationship, system functioning manner, as well as time-dependent system configuration. Firstly, the present paper defines time-domain series system to which the traditional series system reliability model is not adequate. Then, system specific reliability modeling technique is proposed for gear sets, including component (tooth) and subsystem (tooth-pair) load history description, material priori/posterior strength expression, time-dependent and system specific load-strength interference analysis, as well as statistically dependent failure events treatment. Consequently, several system reliability models are developed for gear sets with different tooth numbers in the scenario of tooth root material ultimate tensile strength failure. The application of the models is discussed in the last part, and the differences between the system specific reliability model and the traditional series system reliability model are illustrated by virtue of several numerical examples. - Highlights: • A new type of series system, i.e. time-domain multi-configuration series system is defined, that is of great significance to reliability modeling. • Multi-level statistical analysis based reliability modeling method is presented for gear transmission system. • Several system specific reliability models are established for gear set reliability estimation. • The differences between the traditional series system reliability model and the new model are illustrated.

Interrelationship betwen material strength and component design under elevated temperature for FBR

International Nuclear Information System (INIS)

Nakagawa, Y.

Structural design under elevated temperature for fast breeder reactor plant is very troublesome compared to that of for lower temperature. This difficulty can be mainly discussed from two different stand points. One is design and design code, another is material strength. Components in FBR are operated under creep regime and time dependent creep behaviour should be elevated properly. This means the number and combinations of design code and material strength are significantly large and makes these systems very complicated. Material selection is, in no words, not an easy job. This should be done by not only material development but also component design stand point. With valuable experience of construction and research on FBR, a lot of information on component design and material behaviour is available. And it is a time to choose the ''best material'' from the entire stand points of component construction. (author)

Performance and Reliability of Bonded Interfaces for High-temperature Packaging: Annual Progress Report

Energy Technology Data Exchange (ETDEWEB)

DeVoto, Douglas J. [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2017-10-19

As maximum device temperatures approach 200 °Celsius, continuous operation, sintered silver materials promise to maintain bonds at these high temperatures without excessive degradation rates. A detailed characterization of the thermal performance and reliability of sintered silver materials and processes has been initiated for the next year. Future steps in crack modeling include efforts to simulate crack propagation directly using the extended finite element method (X-FEM), a numerical technique that uses the partition of unity method for modeling discontinuities such as cracks in a system.

Evaluation of Integrated High Temperature Component Testing Needs

Energy Technology Data Exchange (ETDEWEB)

Rafael Soto; David Duncan; Vincent Tonc

2009-05-01

This paper describes the requirements for a large-scale component test capability to support the development of advanced nuclear reactor technology and their adaptation to commercial applications that advance U.S. energy economy, reliability, and security and reduce carbon emissions.

[Simultaneous determination of principal components and related substances of raw material drug of ammonium glycyrrhizinate by reversed-phase high performance liquid chromatography].

Science.gov (United States)

Zhao, Yanyan; Liu, Liyan; Han, Yuanyuan; Li, Yueqiu; Wang, Yan; Shi, Minjian

2013-09-01

An analytical method for the simultaneous determination of 18alpha-glycyrrhizic acid, 18beta-glycyrrhizinic acid, related substances A and B and drug quality standard by reversed-phase high performance liquid chromatography (RP-HPLC) was established. The assay was carried out on a Durashell-C18 column (250 mm x 4.6 mm, 5 microm) with 10 mmol/L ammonium perchlorate (the pH value was adjusted to 8.20 with ammonia)-methanol (48:52, v/v) as mobile phase at a flow rate of 0.80 mL/min, and the detection wavelength was set at 254 nm. The column temperature was 50 degrees C and the injection volume was 10 microL. Under the separation conditions, the calibration curves of the analytes showed good linearities within the mass concentrations of 0.50 -100 mg/L (r > 0.999 9). The detection limits for 18alpha-glycyrrhizic acid, 18beta-glycyrrhizinic acid, related substances A and B were 0.15, 0.10, 0.10, 0.15 mg/L, respectively. The average recoveries were between 97.32% and 99.33% (n = 3) with the relative standard deviations (RSDs) between 0.05% and 1.06%. The method is sensitive, reproducible, and the results are accurate and reliable. The method can be used for the determination of principal components and related substances of ammonium glycyrrhizinate for the quality control of raw material drug of ammonium glycyrrhizinate.

Performance of tungsten-based materials and components under ITER and DEMO relevant steady-state thermal loads

Energy Technology Data Exchange (ETDEWEB)

Ritz, Guillaume Henri

2011-07-01

In nuclear fusion devices the surfaces directly facing the plasma are irradiated with high energy fluxes. The most intense loads are deposited on the divertor located at the bottom of the plasma chamber, which has to withstand continuous heat loads with a power density of several MW . m{sup -2} as well as transient events. These are much shorter (in the millisecond and sub-millisecond regime) but deposit a higher power densities of a few GW . m{sup -2}. The search for materials that can survive to those severe loading conditions led to the choice of tungsten which possesses advantageous attributes such as a high melting point, high thermal conductivity, low thermal expansion and an acceptable activation rate. These properties made it an attractive and promising candidate as armor material for divertors of future fusion devices such as ITER and DEMO. For the DEMO divertor, conceptual studies on helium-cooled tungsten plasma-facing components were performed. The concept was realized and tested under DEMO specific cyclic thermal loads. The examination of the plasma-facing components by microstructural analyses before and after thermal loading enabled to determine the mechanisms for components failure. Among others, it clearly showed the impact of the tungsten grade and the thermal stress induced crack formation on the performance of the armor material and in general of the plasma-facing component under high heat loads. A tungsten qualification program was launched to study the behaviour of various tungsten grades, in particular the crack formation, under fusion relevant steady-state thermal loads. In total, seven commercially available materials from two industrial suppliers were investigated. As the material's thermal response is strongly related to its microstructure, this program comprised different material geometries and manufacturing technologies. It also included the utilization of an actively cooled specimen holder which has been designed to perform

Performance of tungsten-based materials and components under ITER and DEMO relevant steady-state thermal loads

International Nuclear Information System (INIS)

Ritz, Guillaume Henri

2011-01-01

In nuclear fusion devices the surfaces directly facing the plasma are irradiated with high energy fluxes. The most intense loads are deposited on the divertor located at the bottom of the plasma chamber, which has to withstand continuous heat loads with a power density of several MW . m -2 as well as transient events. These are much shorter (in the millisecond and sub-millisecond regime) but deposit a higher power densities of a few GW . m -2 . The search for materials that can survive to those severe loading conditions led to the choice of tungsten which possesses advantageous attributes such as a high melting point, high thermal conductivity, low thermal expansion and an acceptable activation rate. These properties made it an attractive and promising candidate as armor material for divertors of future fusion devices such as ITER and DEMO. For the DEMO divertor, conceptual studies on helium-cooled tungsten plasma-facing components were performed. The concept was realized and tested under DEMO specific cyclic thermal loads. The examination of the plasma-facing components by microstructural analyses before and after thermal loading enabled to determine the mechanisms for components failure. Among others, it clearly showed the impact of the tungsten grade and the thermal stress induced crack formation on the performance of the armor material and in general of the plasma-facing component under high heat loads. A tungsten qualification program was launched to study the behaviour of various tungsten grades, in particular the crack formation, under fusion relevant steady-state thermal loads. In total, seven commercially available materials from two industrial suppliers were investigated. As the material's thermal response is strongly related to its microstructure, this program comprised different material geometries and manufacturing technologies. It also included the utilization of an actively cooled specimen holder which has been designed to perform sophisticated

Some aspects of using Be as high heat flux protective armour material

International Nuclear Information System (INIS)

Gervash, A.; Mazul, I.; Yablokov, N.; Linke, J.

2000-01-01

The beryllium as plasma facing armour material must protect the actively cooled copper alloy heat sink of the First Wall and Divertor components from sputtering erosion, disruption and VDE transients and withstand the number of cycles under expected heat and neutron fluxes. The presented paper discusses some topical questions and presents recent results obtained in Russia in the frame of such consideration. In real operation beryllium as plasma facing component will be subjected to sequence of normal (cyclic heat fluxes) and off-normal (disruption, VDE) heat loads. Aiming to investigate the results of mentioned events the experiments with the number of Russian Be grades (DShG-200, TGP-56, TShG-56, TR-30, Condensed Be) as well as S-65C (ITER reference grade) at simulated disruption loads (∝5 MJ/m 2 ) and subsequent thermal cycling (∝5 MW/m 2 , 1000 cycles) were carried out. Experiments have revealed no macroscopic damage of the tested grades, although significant differences in crack formation and propagation were observed. The main statistics of performed experiments is presented and discussed. One of the main requirements to use Be as a candidate for plasma facing component is providing a reliable joint between Be and Cu-alloy heat sink structure. The unique Russian fast brazing process of joining beryllium to Cu-alloy that allows to survive high heat fluxes ≥10 MW/m 2 during thousand heating/cooling cycles without serious damaging in the armour material and its joint was described in previous works. The main goal of experiments presented in this paper was to study the high heat flux durability limit for joints as function of the pulse duration (i.e. investigation of creep/fatigue interaction). Authors present a description of the testing procedure and discuss the first results of mentioned experiments. (orig.)

Volatile components and continental material of planets

International Nuclear Information System (INIS)

Florenskiy, K.P.; Nikolayeva, O.V.

1984-01-01

It is shown that the continental material of the terrestrial planets varies in composition from planet to planet according to the abundances and composition of true volatiles (H 2 0, CO 2 , etc.) in the outer shells of the planets. The formation of these shells occurs very early in a planet's evolution when the role of endogenous processes is indistinct and continental materials are subject to melting and vaporizing in the absence of an atmosphere. As a result, the chemical properties of continental materials are related not only to fractionation processes but also to meltability and volatility. For planets retaining a certain quantity of true volatile components, the chemical transformation of continental material is characterized by a close interaction between impact melting vaporization and endogeneous geological processes

Achieving High Reliability with People, Processes, and Technology.

Science.gov (United States)

Saunders, Candice L; Brennan, John A

2017-01-01

High reliability as a corporate value in healthcare can be achieved by meeting the "Quadruple Aim" of improving population health, reducing per capita costs, enhancing the patient experience, and improving provider wellness. This drive starts with the board of trustees, CEO, and other senior leaders who ingrain high reliability throughout the organization. At WellStar Health System, the board developed an ambitious goal to become a top-decile health system in safety and quality metrics. To achieve this goal, WellStar has embarked on a journey toward high reliability and has committed to Lean management practices consistent with the Institute for Healthcare Improvement's definition of a high-reliability organization (HRO): one that is committed to the prevention of failure, early identification and mitigation of failure, and redesign of processes based on identifiable failures. In the end, a successful HRO can provide safe, effective, patient- and family-centered, timely, efficient, and equitable care through a convergence of people, processes, and technology.

Design reliability engineering

International Nuclear Information System (INIS)

Buden, D.; Hunt, R.N.M.

1989-01-01

Improved design techniques are needed to achieve high reliability at minimum cost. This is especially true of space systems where lifetimes of many years without maintenance are needed and severe mass limitations exist. Reliability must be designed into these systems from the start. Techniques are now being explored to structure a formal design process that will be more complete and less expensive. The intent is to integrate the best features of design, reliability analysis, and expert systems to design highly reliable systems to meet stressing needs. Taken into account are the large uncertainties that exist in materials, design models, and fabrication techniques. Expert systems are a convenient method to integrate into the design process a complete definition of all elements that should be considered and an opportunity to integrate the design process with reliability, safety, test engineering, maintenance and operator training. 1 fig

Materials and Components for Low Temperature Solid Oxide Fuel Cells – an Overview

Directory of Open Access Journals (Sweden)

D. Radhika

2013-06-01

Full Text Available This article summarizes the recent advancements made in the area of materials and components for low temperature solid oxide fuel cells (LT-SOFCs. LT-SOFC is a new trend in SOFCtechnology since high temperature SOFC puts very high demands on the materials and too expensive to match marketability. The current status of the electrolyte and electrode materials used in SOFCs, their specific features and the need for utilizing them for LT-SOFC are presented precisely in this review article. The section on electrolytes gives an overview of zirconia, lanthanum gallate and ceria based materials. Also, this review article explains the application of different anode, cathode and interconnect materials used for SOFC systems. SOFC can result in better performance with the application of liquid fuels such methanol and ethanol. As a whole, this review article discusses the novel materials suitable for operation of SOFC systems especially for low temperature operation.

A GA based penalty function technique for solving constrained redundancy allocation problem of series system with interval valued reliability of components

Science.gov (United States)

Gupta, R. K.; Bhunia, A. K.; Roy, D.

2009-10-01

In this paper, we have considered the problem of constrained redundancy allocation of series system with interval valued reliability of components. For maximizing the overall system reliability under limited resource constraints, the problem is formulated as an unconstrained integer programming problem with interval coefficients by penalty function technique and solved by an advanced GA for integer variables with interval fitness function, tournament selection, uniform crossover, uniform mutation and elitism. As a special case, considering the lower and upper bounds of the interval valued reliabilities of the components to be the same, the corresponding problem has been solved. The model has been illustrated with some numerical examples and the results of the series redundancy allocation problem with fixed value of reliability of the components have been compared with the existing results available in the literature. Finally, sensitivity analyses have been shown graphically to study the stability of our developed GA with respect to the different GA parameters.

Corrosion of structural materials and electrochemistry in high temperature water of nuclear power systems

International Nuclear Information System (INIS)

Uchida, Shunsuke

2008-01-01

The latest experiences with corrosion in the cooling systems of nuclear power plants are reviewed. High temperature cooling water causes corrosion of structural materials, which often leads to adverse effects in the plants, e.g., increased shutdown radiation, generation of defects in materials of major components and fuel claddings, and increased volume of radwaste sources. Corrosion behavior is greatly affected by water quality and differs according to the water quality values and the materials themselves. In order to establish reliable operation, each plant requires its own unique optimal water chemistry control based on careful consideration of its system, materials and operational history. Electrochemistry is one of the key issues that determine corrosion-related problems, but it is not the only issue. Most corrosion-related phenomena, e.g., flow accelerated corrosion (FAC), intergranular stress corrosion cracking (IGSCC), primary water stress corrosion cracking (PWSCC) and thinning of fuel cladding materials, can be understood based on an electrochemical index, e.g., the electrochemical corrosion potential (ECP), conductivities and pH. The most important electrochemical index, the ECP, can be measured at elevated temperature and applied to in situ sensors of corrosion conditions to detect anomalous conditions of structural materials at their very early stages. (orig.)

Constitutive Theory Developed for Monolithic Ceramic Materials

Science.gov (United States)

Janosik, Lesley A.

1998-01-01

With the increasing use of advanced ceramic materials in high-temperature structural applications such as advanced heat engine components, the need arises to accurately predict thermomechanical behavior that is inherently time-dependent and that is hereditary in the sense that the current behavior depends not only on current conditions but also on the material's thermomechanical history. Most current analytical life prediction methods for both subcritical crack growth and creep models use elastic stress fields to predict the time-dependent reliability response of components subjected to elevated service temperatures. Inelastic response at high temperatures has been well documented in the materials science literature for these material systems, but this issue has been ignored by the engineering design community. From a design engineer's perspective, it is imperative to emphasize that accurate predictions of time-dependent reliability demand accurate stress field information. Ceramic materials exhibit different time-dependent behavior in tension and compression. Thus, inelastic deformation models for ceramics must be constructed in a fashion that admits both sensitivity to hydrostatic stress and differing behavior in tension and compression. A number of constitutive theories for materials that exhibit sensitivity to the hydrostatic component of stress have been proposed that characterize deformation using time-independent classical plasticity as a foundation. However, none of these theories allow different behavior in tension and compression. In addition, these theories are somewhat lacking in that they are unable to capture the creep, relaxation, and rate-sensitive phenomena exhibited by ceramic materials at high temperatures. The objective of this effort at the NASA Lewis Research Center has been to formulate a macroscopic continuum theory that captures these time-dependent phenomena. Specifically, the effort has focused on inelastic deformation behavior associated

Physics-Based Stress Corrosion Cracking Component Reliability Model cast in an R7-Compatible Cumulative Damage Framework

Energy Technology Data Exchange (ETDEWEB)

Unwin, Stephen D.; Lowry, Peter P.; Layton, Robert F.; Toloczko, Mychailo B.; Johnson, Kenneth I.; Sanborn, Scott E.

2011-07-01

This is a working report drafted under the Risk-Informed Safety Margin Characterization pathway of the Light Water Reactor Sustainability Program, describing statistical models of passives component reliabilities.

Draft of standard for graphite core components in high temperature gas-cooled reactor

International Nuclear Information System (INIS)

Shibata, Taiju; Sawa, Kazuhiro; Eto, Motokuni; Kunimoto, Eiji; Shiozawa, Shusaku; Oku, Tatsuo; Maruyama, Tadashi

2010-01-01

For the design of the graphite components in the High Temperature Engineering Test Reactor (HTTR), the graphite structural design code for the HTTR etc. were applied. However, general standard systems for the High Temperature Gas-cooled Reactor (HTGR) have not been established yet. The authors had studied on the technical issues which is necessary for the establishment of a general standard system for the graphite components in the HTGR. The results of the study were documented and discussed at a 'Special committee on research on preparation for codes for graphite components in HTGR' at Atomic Energy Society of Japan (AESJ). As a result, 'Draft of Standard for Graphite Core Components in High Temperature Gas-cooled Reactor.' was established. In the draft standard, the graphite components are classified three categories (A, B and C) in the standpoints of safety functions and possibility of replacement. For the components in the each class, design standard, material and product standards, and in-service inspection and maintenance standard are determined. As an appendix of the design standard, the graphical expressions of material property data of 1G-110 graphite as a function of fast neutron fluence are expressed. The graphical expressions were determined through the interpolation and extrapolation of the irradiated data. (author)

Carbon-carbon composite and copper-composite bond damages for high flux component controlled fusion

International Nuclear Information System (INIS)

Chevet, G.

2010-01-01

Plasma facing components constitute the first wall in contact with plasma in fusion machines such as Tore Supra and ITER. These components have to sustain high heat flux and consequently elevated temperatures. They are made up of an armour material, the carbon-carbon composite, a heat sink structure material, the copper chromium zirconium, and a material, the OFHC copper, which is used as a compliant layer between the carbon-carbon composite and the copper chromium zirconium. Using different materials leads to the apparition of strong residual stresses during manufacturing, because of the thermal expansion mismatch between the materials, and compromises the lasting operation of fusion machines as damage which appeared during manufacturing may propagate. The objective of this study is to understand the damage mechanisms of the carbon-carbon composite and the composite-copper bond under solicitations that plasma facing components may suffer during their life. The mechanical behaviours of carbon-carbon composite and composite-copper bond were studied in order to define the most suitable models to describe these behaviours. With these models, thermomechanical calculations were performed on plasma facing components with the finite element code Cast3M. The manufacturing of the components induces high stresses which damage the carbon-carbon composite and the composite-copper bond. The damage propagates during the cooling down to room temperature and not under heat flux. Alternative geometries for the plasma facing components were studied to reduce damage. The relation between the damage of the carbon-carbon composite and its thermal conductivity was also demonstrated. (author) [fr

Design and optimization of components and processes for plasma sources in advanced material treatments

OpenAIRE

Rotundo, Fabio

2012-01-01

The research activities described in the present thesis have been oriented to the design and development of components and technological processes aimed at optimizing the performance of plasma sources in advanced in material treatments. Consumables components for high definition plasma arc cutting (PAC) torches were studied and developed. Experimental activities have in particular focussed on the modifications of the emissive insert with respect to the standard electrode configuration, whi...

Influence of the effectiveness of raw materials on the reliability of thermoelectric cooling devices. Part I: single-stage TEDs

Directory of Open Access Journals (Sweden)

Zaikov V. P.

2015-02-01

Full Text Available Increase of the reliability of information systems depends on the reliability improvement of their component elements, including cooling devices, providing efficiency of thermally loaded components. Thermoelectric devices based on the Peltier effect have significant advantages compared with air and liquid systems for thermal modes of the radio-electronic equipment. This happens due to the absence of moving parts, which account for the failure rate. The article presents research results on how thermoelectric efficiency modules affect the failure rate and the probability of non-failure operation in the range of working temperature of thermoelectric coolers. The authors investigate a model of relative failure rate and the probability of failure-free operation single-stage thermoelectric devices depending on the main relevant parameters: the operating current flowing through the thermocouple and resistance, temperature changes, the magnitude of the heat load and the number of elements in the module. It is shown that the increase in the thermoelectric efficiency of the primary material for a variety of thermocouple temperature changes causes the following: maximum temperature difference increases by 18%; the number of elements in the module decreases; cooling coefficient increases; failure rate reduces and the probability of non-failure operation of thermoelectric cooling device increases. Material efficiency increase by 1% allows reducing failure rate by 2,6—4,3% in maximum refrigeration capacity mode and by 4,2—5,0% in minimal failure rate mode when temperature difference changes in the range of 40—60 K. Thus, the increase in the thermoelectric efficiency of initial materials of thermocouples can significantly reduce the failure rate and increase the probability of failure of thermoelectric coolers depending on the temperature difference and the current operating mode.

Reliability of the individual components of the Canadian Armed Forces Physical Employment Standard.

Science.gov (United States)

Stockbrugger, Barry G; Reilly, Tara J; Blacklock, Rachel E; Gagnon, Patrick J

2018-01-29

This investigation recruited 24 participants from both the Canadian Armed Forces (CAF) and civilian populations to complete 4 separate trials at "best effort" of each of the 4 components in the CAF Physical Employment Standard named the FORCE Evaluation: Fitness for Operational Requirements of CAF Employment. Analyses were performed to examine the level of variability and reliability within each component. The results demonstrate that candidates should be provided with at least 1 retest if they have recently completed at least 2 previous best effort attempts as per the protocol. In addition, the minimal detectable difference is given for each of the 4 components in seconds which identifies the threshold for subsequent action, either retest or remedial training, for those unable to meet the minimum standard. These results will educate the delivery of this employment standard, function as a method of accommodation, in addition to providing direction for physical training programs.

HIGH-PERFORMANCE COATING MATERIALS

Energy Technology Data Exchange (ETDEWEB)

SUGAMA,T.

2007-01-01

Corrosion, erosion, oxidation, and fouling by scale deposits impose critical issues in selecting the metal components used at geothermal power plants operating at brine temperatures up to 300 C. Replacing these components is very costly and time consuming. Currently, components made of titanium alloy and stainless steel commonly are employed for dealing with these problems. However, another major consideration in using these metals is not only that they are considerably more expensive than carbon steel, but also the susceptibility of corrosion-preventing passive oxide layers that develop on their outermost surface sites to reactions with brine-induced scales, such as silicate, silica, and calcite. Such reactions lead to the formation of strong interfacial bonds between the scales and oxide layers, causing the accumulation of multiple layers of scales, and the impairment of the plant component's function and efficacy; furthermore, a substantial amount of time is entailed in removing them. This cleaning operation essential for reusing the components is one of the factors causing the increase in the plant's maintenance costs. If inexpensive carbon steel components could be coated and lined with cost-effective high-hydrothermal temperature stable, anti-corrosion, -oxidation, and -fouling materials, this would improve the power plant's economic factors by engendering a considerable reduction in capital investment, and a decrease in the costs of operations and maintenance through optimized maintenance schedules.

Determination of basic components and oxidation power of Bi-Sr-Ca-Cu-O high temperature superconducting materials

International Nuclear Information System (INIS)

Vesene, T.B.

1993-01-01

A combination of methods is suggested for photometric determination of basic components of samples of bismuth-, strontium-, calcium-, and copper-based materials. A microchemical analysis is performed from one specimen without preliminary separation of components. Bismuth is singled out in the form of its complex with xylenol orange, calcium is defined in the form if its complex with calcion, strontium - in the form of its complex with chlorophosphonazo 3, and copper - in the form of its complex with PAR. Nonstoichiometric oxygen is detected via photometric evaluation of triiodine ions

High power klystrons for efficient reliable high power amplifiers

Science.gov (United States)

Levin, M.

1980-11-01

This report covers the design of reliable high efficiency, high power klystrons which may be used in both existing and proposed troposcatter radio systems. High Power (10 kW) klystron designs were generated in C-band (4.4 GHz to 5.0 GHz), S-band (2.5 GHz to 2.7 GHz), and L-band or UHF frequencies (755 MHz to 985 MHz). The tubes were designed for power supply compatibility and use with a vapor/liquid phase heat exchanger. Four (4) S-band tubes were developed in the course of this program along with two (2) matching focusing solenoids and two (2) heat exchangers. These tubes use five (5) tuners with counters which are attached to the focusing solenoids. A reliability mathematical model of the tube and heat exchanger system was also generated.

Nondestructive Examination (NDE) Reliability for Inservice Inspection of Light Water Reactors

International Nuclear Information System (INIS)

Doctor, S.R.; Diaz, A.A.; Friley, J.R.; Good, M.S.; Greenwood, M.S.; Heasler, P.G.; Hockey, R.L.; Kurtz, R.J.; Simonen, F.A.; Spanner, J.C.; Taylor, T.T.; Vo, T.V.

1992-07-01

The Evaluation and Improvement of NDE Reliability for Inservice Inspection of Light Water Reactors (NDE Reliability) Program at the Pacific Northwest Laboratory was established by the Nuclear Regulatory Commission to determine the reliability of current inservice inspection (ISI) techniques and to develop recommendations that will ensure a suitably high inspection reliability. The objectives of this program include determining the reliability of ISI performed on the primary systems of commercial light-water reactors (LWR's); using probabilistic fracture mechanics analysis to determine the impact of NDE unreliability on system safety; and evaluating reliability improvements that can be achieved with improved and advanced technology. A final objective is to formulate recommended revisions to the Regulatory and ASME Code requirements, based on material properties, service conditions, and NDE uncertainties. The program scope is limited to ISI of the primary systems including the piping, vessel, and other components inspected in accordance with Section XI of the ASME Code. This is a progress report covering the programmatic work from April 1991 through September 1991

Nondestructive Examination (NDE) Reliability for Inservice Inspection of Light Water Reactors

International Nuclear Information System (INIS)

Doctor, S.R.; Diaz, A.A.; Friley, J.R.; Greenwood, M.S.; Heasler, P.G.; Kurtz, R.J.; Simonen, F.A.; Spanner, J.C.; Vo, T.V.

1993-11-01

The Evaluation and Improvement of NDE Reliability for Inservice inspection of Light Water Reactors (NDE Reliability) Program at the Pacific Northwest Laboratory was established by the Nuclear Regulatory Commission to determine the reliability of current inservice inspection (ISI) techniques and to develop recommendations that will ensure a suitably high inspection reliability. The objectives of this program include determining the reliability of ISI performed on the primary systems of commercial light-water reactors (LWRs);using probabilistic fracture mechanics analysis to determine the impact of NDE unreliability on system safety; and evaluating reliability improvements that can be achieved with improved and advanced technology. A final objective is to formulate recommended revisions to the Regulatory and ASME Code requirements, based on material properties, service conditions, and NDE uncertainties. The program scope is limited to ISI of the primary systems including the piping, vessel and other components inspected in accordance with Section XI of the ASME Code. This is a programs report covering the programmatic work from April 1992 through September 1992

Nondestructive examination (NDE) reliability for inservice inspection of light water reactors

International Nuclear Information System (INIS)

Doctor, S.R.; Good, M.S.; Green, E.R.; Heasler, P.G.; Simonen, F.A.; Spanner, J.C.; Taylor, T.T.; Vo, T.V.

1991-08-01

The Evaluation and Improvement of NDE Reliability for Inservice Inspection of Light Water Reactors (NDE Reliability) Program at the Pacific Northwest Laboratory was established by the Nuclear Regulatory Commission to determine the reliability of current inservice inspection (ISI) techniques and to develop recommendations that will ensure a suitably high inspection reliability. The objectives of this program include determining the reliability of ISI performed on the primary systems of commercial light-water reactors (LWRs); using probabilistic fracture mechanics analysis to determine the impact of NDE unreliability on system safety; and evaluating reliability improvements that can be achieved with improved and advanced technology. A final objective is to formulate recommended revisions to ASME Code and Regulatory requirements, based on material properties, service conditions, and NDE uncertainties. The program scope is limited to ISI of the primary systems including the piping, vessel, and other components inspected in accordance with Section 6 of the ASME Code. This is a progress report covering the pro grammatic work from April 1989 through September 1989. 12 refs., 4 figs. 5 tabs

Development of core technology for KNGR system design; development of quantitative reliability evaluation methodologies of KNGR digital I and C components

Energy Technology Data Exchange (ETDEWEB)

Seong, Poong Hyun; Choi, Jong Gyun; Kim, Ung Soo; Kim, Jong Hyun; Kim, Man Cheol; Lee, Seung Jun; Lee, Young Je; Ha, Jun Soo [Korea Advanced Institute of Science and Technology, Taejeon (Korea)

2002-03-01

For the digital systems to be applied to the nuclear industry, which has its unique conservertive to safety, reliability assessment of digital systems is a prerequisite. But, because digital systems show different failure modes from compared to existing analog systems, the existing reliability assessment method cannot be applied to digital systems. It means that a new reliability assessment method for digital systems should be developed. The goal of this study is development of reliability assessment method for digital systems on board level and related software tool. To achieve the goal, we have conducted researches on development of a database for hardware components for digital I and C systems, development of a reliability assessment model for the reliability prediction of digital systems on board level, and the applicability to KNGR digital I and C systems. We developed a database for reliability assessment of digital hardware components, a reliability assessment method for digital systems with consideration of software and hardware together, and a software tool for the reliability assessment of digital systems, which is named as RelPredic. We plan to apply the results of this study to the reliability assessment of digital systems in KNGR digital I and C systems. 13 refs., 71 figs., 31 tabs. (Author)

LTCC magnetic components for high density power converter

Science.gov (United States)

Lebourgeois, Richard; Labouré, Eric; Lembeye, Yves; Ferrieux, Jean-Paul

2018-04-01

This paper deals with multilayer magnetic components for power electronics application and specifically for high frequency switching. New formulations based on nickel-zinc-copper spinel ferrites were developed for high power and high frequency applications. These ferrites can be sintered at low temperature (around 900°C) which makes them compatible with the LTCC (Low Temperature Co-fired Ceramics) technology. Metallic parts of silver or gold can be fully integrated inside the ferrite while guaranteeing the integrity of both the ferrite and the metal. To make inductors or transformers with the required properties, it is mandatory to have nonmagnetic parts between the turns of the winding. Then it is essential to find a dielectric material, which can be co-sintered both with the ferrite and the metal. We will present the solution we found to this problem and we will describe the results we obtained for a multilayer co-sintered transformer. We will see that these new components have good performance compared with the state of the art and are very promising for developing high density switching mode power supplies.

Generation IV Reactors Integrated Materials Technology Program Plan: Focus on Very High Temperature Reactor Materials

Energy Technology Data Exchange (ETDEWEB)

Corwin, William R [ORNL; Burchell, Timothy D [ORNL; Katoh, Yutai [ORNL; McGreevy, Timothy E [ORNL; Nanstad, Randy K [ORNL; Ren, Weiju [ORNL; Snead, Lance Lewis [ORNL; Wilson, Dane F [ORNL

2008-08-01

the structural materials needed to ensure their safe and reliable operation. The focus of this document will be the overall range of DOE's structural materials research activities being conducted to support VHTR development. By far, the largest portion of material's R&D supporting VHTR development is that being performed directly as part of the Next-Generation Nuclear Plant (NGNP) Project. Supplementary VHTR materials R&D being performed in the DOE program, including university and international research programs and that being performed under direct contracts with the American Society for Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, will also be described. Specific areas of high-priority materials research that will be needed to deploy the NGNP and provide a basis for subsequent VHTRs are described, including the following: (1) Graphite: (a) Extensive unirradiated materials characterization and assessment of irradiation effects on properties must be performed to qualify new grades of graphite for nuclear service, including thermo-physical and mechanical properties and their changes, statistical variations from billot-to-billot and lot-to-lot, creep, and especially, irradiation creep. (b) Predictive models, as well as codification of the requirements and design methods for graphite core supports, must be developed to provide a basis for licensing. (2) Ceramics: Both fibrous and load-bearing ceramics must be qualified for environmental and radiation service as insulating materials. (3) Ceramic Composites: Carbon-carbon and SiC-SiC composites must be qualified for specialized usage in selected high-temperature components, such as core stabilizers, control rods, and insulating covers and ducting. This will require development of component-specific designs and fabrication processes, materials characterization, assessment of environmental and irradiation effects, and establishment of codes and standards for materials testing and design

Development of radiation hard components for ITER blanket remote handling system

Energy Technology Data Exchange (ETDEWEB)

Saito, Makiko, E-mail: saito.makiko@jaea.go.jp; Anzai, Katsunori; Maruyama, Takahito; Noguchi, Yuto; Ueno, Kenichi; Takeda, Nobukazu; Kakudate, Satoshi

2016-11-01

Highlights: • Clarify the components that will degrade by gamma ray irradiation. • Perform the irradiation tests to BRHS components. • Optimize the materials to increase the radiation hardness. - Abstract: The ITER blanket remote handling system (BRHS) will be operated in a high radiation environment (250 Gy/h max.) and must stably handle the blanket modules, which weigh 4.5 t and are more than 1.5 m in length, with a high degree of position and posture accuracy. The reliability of the system can be improved by reviewing the failure events of the system caused by high radiation. A failure mode and effects analysis (FMEA) identified failure modes and determined that lubricants, O-rings, and electric insulation cables were the dominant components affecting radiation hardness. Accordingly, we tried to optimize the lubricants and cables of the AC servo motors by using polyphenyl ether (PPE)-based grease and polyether ether ketone (PEEK), respectively. Materials containing radiation protective agents were also selected for the cable sheaths and O-rings to improve radiation hardness. Gamma ray irradiation tests were performed on these components and as a result, a radiation hardness of 8 MGy was achieved for the AC servo motors. On the other hand, to develop the radiation hardness and BRHS compatibility furthermore, the improvement of materials of cable and O ring were performed.

High temperature resistant materials and structural ceramics for use in high temperature gas cooled reactors and fusion plants

International Nuclear Information System (INIS)

Nickel, H.

1992-01-01

Irrespective of the systems and the status of the nuclear reactor development lines, the availability, qualification and development of materials are crucial. This paper concentrates on the requirements and the status of development of high temperature metallic and ceramic materials for core and heat transferring components in advanced HTR supplying process heat and for plasma exposed, high heat flux components in Tokamak fusion reactor types. (J.P.N.)

Decarburisation Effect on Hardened Strip Steel Fastening Components

Directory of Open Access Journals (Sweden)

Karli JAASON

2016-05-01

Full Text Available Heat treatment is widely used for high reliability fastening components such as buckles and brackets. The current study focuses on mass production of safety components which are fineblanked from sheet metal, austempered and chromium electroplated. Electroplating together with stamping defects may lead to unexpected brittle failure of the component. It is widely known that during austenitisation, decarburisation could avoid brittle failure and, therefore, slight decarburisation is recommended. There is little information how much mass production is influenced by decarburisation and where the limits are. The current study has two goals. The first one focuses on the extent of decarburisation effect on the part properties, and the second aims to find the optimum furnace setting for the product type used in the study. Also, it is necessary to choose a reliable decarburisation control method for austempered components. The effect on material grades was analyzed by using three steel alloys with carbon content of 0.37 wt.%, 0.47 wt.% and 0.62 wt.%. The specimens were austempered to hardness 45 – 51 HRC under endothermic protective atmosphere. To gain different decarburisation levels, two gas set-ups were used. Infrared gas analyzer was used to measure CO and CO2 content in the furnace gas. Three characteristics of the specimens were evaluated: hardness, rupture strength and brittleness. The depth of the decarburisation was determined by three different approaches according to standard EN ISO 3887. Based on the results, the spectrographic method is the most reliable for determining the depth of decarburisation. This study reveals that higher surface decarburisation has a positive effect on the ductility and no effect on the rupture strength of the component. The material with carbon content of 0.62 wt.% is the most sensitive to decarburisation. During mass production, the inaccuracy of hardness measuring raises which results in the inaccuracy of

Composition of estuarine colloidal material: organic components

Science.gov (United States)

Sigleo, A.C.; Hoering, T.C.; Helz, G.R.

1982-01-01

Colloidal material in the size range 1.2 nm to 0.4 ??m was isolated by ultrafiltration from Chesapeake Bay and Patuxent River waters (U.S.A.). Temperature controlled, stepwise pyrolysis of the freeze-dried material, followed by gas chromatographic-mass spectrometric analyses of the volatile products indicates that the primary organic components of this polymer are carbohydrates and peptides. The major pyrolysis products at the 450??C step are acetic acid, furaldehydes, furoic acid, furanmethanol, diones and lactones characteristic of carbohydrate thermal decomposition. Pyrroles, pyridines, amides and indole (protein derivatives) become more prevalent and dominate the product yield at the 600??C pyrolysis step. Olefins and saturated hydrocarbons, originating from fatty acids, are present only in minor amounts. These results are consistent with the composition of Chesapeake phytoplankton (approximately 50% protein, 30% carbohydrate, 10% lipid and 10% nucleotides by dry weight). The pyrolysis of a cultured phytoplankton and natural particulate samples produced similar oxygen and nitrogencontaining compounds, although the proportions of some components differ relative to the colloidal fraction. There were no lignin derivatives indicative of terrestrial plant detritus in any of these samples. The data suggest that aquatic microorganisms, rather than terrestrial plants, are the dominant source of colloidal organic material in these river and estuarine surface waters. ?? 1982.

T-book. Reliability data of components in Nordic nuclear power plants. 6. ed

International Nuclear Information System (INIS)

2005-01-01

The main objective of the T-Book is to provide reliability data for the unavailability computations that are made for each component that is considered in the compulsory, probabilistic safety assessments (PSA) of nuclear power plants. As the use of PSA is large in the normal safety work at the NPPs, there is a need for easily accessible and reliable failure data. The failure characteristics presented in the T-Book are primarily based on the failure reports stored in the central database TUD and the Licensee Event Reports delivered to the Swedish Nuclear Power Inspectorate (SKI). Fortunately, the TUD database was started already in the middle of the seventies by the Swedish power companies. In 1981, the Finnish power company TVO, operating two reactor units of Swedish design, joined the data collection system. Before the TUD data are statistically treated they are carefully examined with respect to the consistency and correctness. This T-Book comprises only critical failures, i.e. failures that stops the function of components or leads to repair. The first edition of the T-Book was issued in 1982 encompassing operational statistics from 21 reactor years. The second edition was published 1985, based on operating data covering about 40 reactor years. The T-Book 3 was published in 1992 and included data up to the operating year 1987 (108 reactor years). Edition 4 was published 1994 containing information up to and including 1992 (178 reactor years). Edition 5 was published year 2000 containing information up to and including 1996 (234 reactor years). This edition 6 contains information including year 2002 (315 reactor years). At the same time as the amount of data has increased with the successive editions of the T-Book there has been a continuous work to improve the methods for the statistical inference and related program tools, required to derive the reliability parameters from the operational data in the database. Already in the initial edition there was a Bayesian

Influence of material choice on cost estimation of some key components of the Sulfur Iodine thermochemical process

International Nuclear Information System (INIS)

Gilardi, T.; Rodriguez, G.; Gomez, A.; Leybros, J.; Borgard, J.M.; Carles, P.; Anzieu, P.

2006-01-01

In the frame of the preliminary design of an sulfur/iodine thermochemical plant coupled with a 600 MWth Helium cooled High Temperature Reactor, CEA has pre-designed all the components of the I/S plant and has started to the cost estimation of all the key components with some industrial cost evaluation methods proposed by CHAUVEL or PETER and TIMMERHAUS. The purpose of the paper is to present the strong influence of material choice on final cost estimation of these key components by comparing price with standard material (steel) and the most appropriate material selected to support the strong corrosion involved by several chemical reactions of the I/S process. These results reinforce the fact that material selection must be done with the best accuracy and that it will be a key factor in the global economy of these plant investment. (authors)

Reliability Evaluation on Creep Life Prediction of Alloy 617 for a Very High Temperature Reactor

International Nuclear Information System (INIS)

Kim, Woo-Gon; Hong, Sung-Deok; Kim, Yong-Wan; Park, Jae-Young; Kim, Seon-Jin

2012-01-01

This paper evaluates the reliability of creep rupture life under service conditions of Alloy 617, which is considered as one of the candidate materials for use in a very high temperature reactor (VHTR) system. A Z-parameter, which represents the deviation of creep rupture data from the master curve, was used for the reliability analysis of the creep rupture data of Alloy 617. A Service-condition Creep Rupture Interference (SCRI) model, which can consider both the scattering of the creep rupture data and the fluctuations of temperature and stress under any service conditions, was also used for evaluating the reliability of creep rupture life. The statistical analysis showed that the scattering of creep rupture data based on Z-parameter was supported by normal distribution. The values of reliability decreased rapidly with increasing amplitudes of temperature and stress fluctuations. The results established that the reliability decreased with an increasing service time.

Highly Efficient and Reliable Transparent Electromagnetic Interference Shielding Film.

Science.gov (United States)

Jia, Li-Chuan; Yan, Ding-Xiang; Liu, Xiaofeng; Ma, Rujun; Wu, Hong-Yuan; Li, Zhong-Ming

2018-04-11

Electromagnetic protection in optoelectronic instruments such as optical windows and electronic displays is challenging because of the essential requirements of a high optical transmittance and an electromagnetic interference (EMI) shielding effectiveness (SE). Herein, we demonstrate the creation of an efficient transparent EMI shielding film that is composed of calcium alginate (CA), silver nanowires (AgNWs), and polyurethane (PU), via a facile and low-cost Mayer-rod coating method. The CA/AgNW/PU film with a high optical transmittance of 92% achieves an EMI SE of 20.7 dB, which meets the requirements for commercial shielding applications. A superior EMI SE of 31.3 dB could be achieved, whereas the transparent film still maintains a transmittance of 81%. The integrated efficient EMI SE and high transmittance are superior to those of most previously reported transparent EMI shielding materials. Moreover, our transparent films exhibit a highly reliable shielding ability in a complex service environment, with 98 and 96% EMI SE retentions even after 30 min of ultrasound treatment and 5000 bending cycles (1.5 mm radius), respectively. The comprehensive performance that is associated with the facile fabrication strategy imparts the CA/AgNW/PU film with great potential as an optimized EMI shielding material in emerging optoelectronic devices, such as flexible solar cells, displays, and touch panels.

Reliability of the Phi angle to assess rotational alignment of the talar component in total ankle replacement.

Science.gov (United States)

Manzi, Luigi; Villafañe, Jorge Hugo; Indino, Cristian; Tamini, Jacopo; Berjano, Pedro; Usuelli, Federico Giuseppe

2017-11-08

The purpose of this study was to investigate the test-retest reliability of the Phi angle in patients undergoing total ankle replacement (TAR) for end stage ankle osteoarthritis (OA) to assess the rotational alignment of the talar component. Retrospective observational cross-sectional study of prospectively collected data. Post-operative anteroposterior radiographs of the foot of 170 patients who underwent TAR for the ankle OA were evaluated. Three physicians measured Phi on the 170 randomly sorted and anonymized radiographs on two occasions, one week apart (test and retest conditions), inter and intra-observer agreement were evaluated. Test-retest reliability of Phi angle measurement was excellent for patients with Hintegra TAR (ICC=0.995; pPhi angle measurement between patients with Hintegra vs. Zimmer implants (p>0.05). Measurement of Phi angle on weight-bearing dorsoplantar radiograph showed an excellent reliability among orthopaedic surgeons in determining the position of the talar component in the axial plane. Level II, cross sectional study. Copyright © 2017 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

Viscoplastic Constitutive Theory Demonstrated for Monolithic Ceramic Materials

Science.gov (United States)

Janosik, Lesley A.

1999-01-01

Development of accurate three-dimensional (multiaxial) inelastic stress-strain models is critical in utilizing advanced ceramics for challenging 21st century high-temperature structural applications. The current state of the art uses elastic stress fields as a basis for both subcritical crack growth and creep life prediction efforts aimed at predicting the time dependent reliability response of ceramic components subjected to elevated service temperatures. However, to successfully design components that will meet tomorrow's challenging requirements, design engineers must recognize that elastic predictions are inaccurate for these materials when subjected to high-temperature service conditions such as those encountered in advanced heat engine components. Analytical life prediction methodologies developed for advanced ceramics and other brittle materials must employ accurate constitutive models that capture the inelastic response exhibited by these materials at elevated service temperatures. A constitutive model recently developed at the NASA Lewis Research Center helps address this issue by accounting for the time-dependent (inelastic) material deformation phenomena (e.g., creep, rate sensitivity, and stress relaxation) exhibited by monolithic ceramics exposed to high-temperature service conditions. In addition, the proposed formulation is based on a threshold function that is sensitive to hydrostatic stress and allows different behavior in tension and compression, reflecting experimental observations obtained for these material systems.

The reliability of radiochemical and chemical trace analyses in environmental materials

International Nuclear Information System (INIS)

Heinonen, Jorma.

1977-12-01

After theoretically exploring the factors which influence the quality of analytical data as well as the means by which a sufficient quality can be assured and controlled, schemes of different kinds have been developed and applied in order to demonstrate the analytical quality assurance and control in practice. Methods have been developed for the determination of cesium, bromine and arsenic by neutron activation analysis at the natural ''background'' concentration level in environmental materials. The calibration of methods is described. The methods were also applied on practical routine analysis, the results of which are briefly reviewed. In the case of Ce the precision of a comprehensive calibration was found to vary between 5.2-9.2% as a relative standard deviation, which agrees well with the calculated statistical random error 5.7-8.7%. In the case of Br the method showed a reasonable precision, about 11% on the average, and accuracy. In employing the method to analyze died samples containing Br from 3 to 12 ppm a continuous control of precison was performed. The analysis of As demonstrates the many problems and difficulties associated with environmental analysis. In developing the final method four former intercomparison materials of IAEA were utilized in the calibration. The tests performed revealed a systematic error. In this case a scheme was developed for the continuous control of both precision and accuracy. The results of radiochemical analyses in environmental materials show a reliability somewhat better than that occuring in the determination of stable trace elements. According to a rough classification, 15% of the results of radiochemical analysis show excellent reliability, whereas 60% show a reliability adequate for certain purposes. The remaining 15% are excellent, 60% adequate for some purposes and 30% good-for-nothing. The reasons for often insufficient reliability of results are both organizational and technical. With reasonable effort and

State of the Art in Life Assessment for High Temperature Components Using Replication Method

International Nuclear Information System (INIS)

Kim, Duck Hee; Choi, Hyun Sun

2010-01-01

The power generation and chemical industry have been subjected to further material degradation with long term operations and need to predict the remaining service life of components, such as reformer tube and turbine rotor, that have operated at elevated temperatures. As a non-destructive technique, replication method with reliable metallurgical life and microstructural soundness assessment has been recognized with strongly useful method until now. Developments of this method have variously accomplished by new quantitative approach, such as carbide analysis, with A-parameter and grain deformation method. An overview of replication, some new techniques for material degradation and life assessment were introduced in this paper. Also, on-site applications and its reasonableness were described. As a result of having analyzed microstructure by replication method, carbide approach was quantitatively useful to life assessment

Materials performance in a high-level radioactive waste vitrification system

International Nuclear Information System (INIS)

Imrich, K.J.; Chandler, G.T.

1996-01-01

The Defense Waste Processing Facility (DWPF) is a Department of Energy Facility designed to vitrify highly radioactive waste. An extensive materials evaluation program has been completed on key components in the DWPF after twelve months of operation using nonradioactive simulated wastes. Results of the visual inspections of the feed preparation system indicate that the system components, which were fabricated from Hastelloy C-276, should achieve their design lives. Significant erosion was observed on agitator blades that process glass frit slurries; however, design modifications should mitigate the erosion. Visual inspections of the DWPF melter top head and off gas components, which were fabricated from Inconel 690, indicated that varying degrees of degradation occurred. Most of the components will perform satisfactorily for their two year design life. The components that suffered significant attack were the borescopes, primary film cooler brush, and feed tubes. Changes in the operation of the film cooler brush and design modifications to the feed tubes and borescopes is expected to extend their service lives to two years. A program to investigate new high temperature engineered materials and alloys with improved oxidation and high temperature corrosion resistance will be initiated

Mission Reliability Estimation for Repairable Robot Teams

Science.gov (United States)

Trebi-Ollennu, Ashitey; Dolan, John; Stancliff, Stephen

2010-01-01

A mission reliability estimation method has been designed to translate mission requirements into choices of robot modules in order to configure a multi-robot team to have high reliability at minimal cost. In order to build cost-effective robot teams for long-term missions, one must be able to compare alternative design paradigms in a principled way by comparing the reliability of different robot models and robot team configurations. Core modules have been created including: a probabilistic module with reliability-cost characteristics, a method for combining the characteristics of multiple modules to determine an overall reliability-cost characteristic, and a method for the generation of legitimate module combinations based on mission specifications and the selection of the best of the resulting combinations from a cost-reliability standpoint. The developed methodology can be used to predict the probability of a mission being completed, given information about the components used to build the robots, as well as information about the mission tasks. In the research for this innovation, sample robot missions were examined and compared to the performance of robot teams with different numbers of robots and different numbers of spare components. Data that a mission designer would need was factored in, such as whether it would be better to have a spare robot versus an equivalent number of spare parts, or if mission cost can be reduced while maintaining reliability using spares. This analytical model was applied to an example robot mission, examining the cost-reliability tradeoffs among different team configurations. Particularly scrutinized were teams using either redundancy (spare robots) or repairability (spare components). Using conservative estimates of the cost-reliability relationship, results show that it is possible to significantly reduce the cost of a robotic mission by using cheaper, lower-reliability components and providing spares. This suggests that the

Flaw assessment procedure for high temperature reactor components

International Nuclear Information System (INIS)

Ainsworth, R.A.; Takahashi, Y.

1990-01-01

An interim high-temperature flaw assessment procedure is described. This is a result of a collaborative effort between Electric Power Research Institute in the USA, Central Research Institute of Electric Power Industry in Japan, and Nuclear Electric plc in the UK. The procedure addresses preexisting defects subject to creep-fatigue loading conditions. Laws employed to calculate the crack growth per cycle are defined in terms of fracture mechanics parameters and constants related to the component material. The crack growth laws may be integrated to calculate the remaining life of a component or to predict the amount of crack extension in a given period. Fatigue and creep crack growth per cycle are calculated separately, and the total crack extension is taken as the simple sum of the two contributions. An interaction between the two propagation modes is accounted for in the material properties in the separate calculations. In producing the procedure, limitations of the approach have been identified. Some of these limitations are to be addressed in an extension of the current collaborative program. 20 refs

Determination of material behavior in 700 C turbine components under component and load specific conditions

Energy Technology Data Exchange (ETDEWEB)

Lueckemeyer, N.; Kirchner, H.; Kern, T.U. [Siemens AG, Muehlheim (Germany). Energy Sector; Reigl, M. [Alstom Power, Baden (Switzerland); Klenk, A.; Klein, T. [Stuttgart Univ. (Germany). MPA; Schwienheer, M.; Cui, L.; Scholz, A.; Berger, C. [Institut fuer Werkstoffkunde (IfW), Darmstadt (Germany)

2010-07-01

With global warming being one of mankind's greatest challenges, an increasing demand for electricity world-wide, and studies showing that fossil resources like coal and gas will remain a major source for electricity for the next couple of decades, research into the development of highest efficiency fossil power plants has become a top priority. Calculations for coal fired power plants have shown that CO{sub 2} emissions can be reduced by as much as 7% compared to the current state of the art equipment. It can be reached by increasing the live steam parameters to 700 C and 350bar. To achieve the desired operating hours at this temperature the application of nickel base materials is necessary for the main components such as rotors, inner casings and valves. Nowadays, the use of Nickel base alloys is common practice for selected gas turbine components. However, with steam turbine rotors being 1000mm in diameter and casings with wall thicknesses higher than 100mm the gas turbine application range and experience for nickel base alloys are well exceeded. This paper uses a basic design for a steam turbine to illustrate the core challenges in developing nickel based steam turbine components, such as casting, forging, nondestructive testing and welding. Suitable nickel based alloys have been investigated in research projects over the past years. The research results are summarized and an explanation is given as to why Alloy617 was selected for forged components and Alloy625 for cast components. This paper then focuses on the material behavior under long term and complex loading conditions and on the development of life time concepts for thick walled components made from these alloys. Due to the differences in the material behavior of nickel base alloys, the existing steel design philosophies cannot be completely adopted but rather must be carefully evaluated and modified where necessary. To do this, large test components were manufactured. Based on both standard tests

Reliability calculation of cracked components using probabilistic fracture mechanics and a Markovian approach

International Nuclear Information System (INIS)

Schmidt, T.

1988-01-01

The numerical reliability calculation of cracked construction components under cyclical fatigue stress can be done with the help of models of probabilistic fracture mechanics. An alternative to the Monte Carlo simulation method is examined; the alternative method is based on the description of failure processes with the help of a Markov process. The Markov method is traced back directly to the stochastic parameters of a two-dimensional fracture mechanics model, the effects of inspections and repairs also being considered. The probability of failure and expected failure frequency can be determined as time functions with the transition and conditional probabilities of the original or derived Markov process. For concrete calculation, an approximative Markov chain is designed which, under certain conditions, is capable of giving a sufficient approximation of the original Markov process and the reliability characteristics determined by it. The application of the MARKOV program code developed into an algorithm reveals sufficient conformity with the Monte Carlo reference results. The starting point of the investigation was the 'Deutsche Risikostudie B (DWR)' ('German Risk Study B (DWR)'), specifically, the reliability of the main coolant line. (orig./HP) [de

Sandia_HighTemperatureComponentEvaluation_2015

Energy Technology Data Exchange (ETDEWEB)

Cashion, Avery T. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-03-01

The objective of this project is to perform independent evaluation of high temperature components to determine their suitability for use in high temperature geothermal tools. Development of high temperature components has been increasing rapidly due to demand from the high temperature oil and gas exploration and aerospace industries. Many of these new components are at the late prototype or first production stage of development and could benefit from third party evaluation of functionality and lifetime at elevated temperatures. In addition to independent testing of new components, this project recognizes that there is a paucity of commercial-off-the-shelf COTS components rated for geothermal temperatures. As such, high-temperature circuit designers often must dedicate considerable time and resources to determine if a component exists that they may be able to knead performance out of to meet their requirements. This project aids tool developers by characterization of select COTS component performances beyond published temperature specifications. The process for selecting components includes public announcements of project intent (e.g., FedBizOps), direct discussions with candidate manufacturers,and coordination with other DOE funded programs.

Gas turbine blades and disks. Materials and component behaviour

International Nuclear Information System (INIS)

1990-01-01

This progress report summarizes the research results obtained by the special research programme 339 in the years 1988 and 1989. Emphasis is given to the following aspects and problems: Optimisation of structure, protective coatings, connection between structure parameters and mechanical materials behaviour, tribologic materials and component behaviour, impacts of overall loads, and of stress and deformation state in the inelastic regime under mechanical and thermal load, and impacts of the manufacturing process on component behaviour, quality assurance. Eleven of the fifteen papers of the report have been separately analysed for the ENERGY database, and thirteen for the DELURA database. (orig./MM) With 191 figs., 13 tabs [de

Adjoint sensitivity analysis of dynamic reliability models based on Markov chains - II: Application to IFMIF reliability assessment

Energy Technology Data Exchange (ETDEWEB)

Cacuci, D. G. [Commiss Energy Atom, Direct Energy Nucl, Saclay, (France); Cacuci, D. G.; Balan, I. [Univ Karlsruhe, Inst Nucl Technol and Reactor Safetly, Karlsruhe, (Germany); Ionescu-Bujor, M. [Forschungszentrum Karlsruhe, Fus Program, D-76021 Karlsruhe, (Germany)

2008-07-01

In Part II of this work, the adjoint sensitivity analysis procedure developed in Part I is applied to perform sensitivity analysis of several dynamic reliability models of systems of increasing complexity, culminating with the consideration of the International Fusion Materials Irradiation Facility (IFMIF) accelerator system. Section II presents the main steps of a procedure for the automated generation of Markov chains for reliability analysis, including the abstraction of the physical system, construction of the Markov chain, and the generation and solution of the ensuing set of differential equations; all of these steps have been implemented in a stand-alone computer code system called QUEFT/MARKOMAG-S/MCADJSEN. This code system has been applied to sensitivity analysis of dynamic reliability measures for a paradigm '2-out-of-3' system comprising five components and also to a comprehensive dynamic reliability analysis of the IFMIF accelerator system facilities for the average availability and, respectively, the system's availability at the final mission time. The QUEFT/MARKOMAG-S/MCADJSEN has been used to efficiently compute sensitivities to 186 failure and repair rates characterizing components and subsystems of the first-level fault tree of the IFMIF accelerator system. (authors)

Adjoint sensitivity analysis of dynamic reliability models based on Markov chains - II: Application to IFMIF reliability assessment

International Nuclear Information System (INIS)

Cacuci, D. G.; Cacuci, D. G.; Balan, I.; Ionescu-Bujor, M.

2008-01-01

In Part II of this work, the adjoint sensitivity analysis procedure developed in Part I is applied to perform sensitivity analysis of several dynamic reliability models of systems of increasing complexity, culminating with the consideration of the International Fusion Materials Irradiation Facility (IFMIF) accelerator system. Section II presents the main steps of a procedure for the automated generation of Markov chains for reliability analysis, including the abstraction of the physical system, construction of the Markov chain, and the generation and solution of the ensuing set of differential equations; all of these steps have been implemented in a stand-alone computer code system called QUEFT/MARKOMAG-S/MCADJSEN. This code system has been applied to sensitivity analysis of dynamic reliability measures for a paradigm '2-out-of-3' system comprising five components and also to a comprehensive dynamic reliability analysis of the IFMIF accelerator system facilities for the average availability and, respectively, the system's availability at the final mission time. The QUEFT/MARKOMAG-S/MCADJSEN has been used to efficiently compute sensitivities to 186 failure and repair rates characterizing components and subsystems of the first-level fault tree of the IFMIF accelerator system. (authors)

On the optimal scheduling of periodic tests and maintenance for reliable redundant components

International Nuclear Information System (INIS)

Courtois, Pierre-Jacques; Delsarte, Philippe

2006-01-01

Periodically, some m of the n redundant components of a dependable system may have to be taken out of service for inspection, testing or preventive maintenance. The system is then constrained to operate with lower (n-m) redundancy and thus with less reliability during these periods. However, more frequent periodic inspections decrease the probability that a component fail undetected in the time interval between successive inspections. An optimal time schedule of periodic preventive operations arises from these two conflicting factors, balancing the loss of redundancy during inspections against the reliability benefits of more frequent inspections. Considering no other factor than this decreased redundancy at inspection time, this paper demonstrates the existence of an optimal interval between inspections, which maximizes the mean time between system failures. By suitable transformations and variable identifications, an analytic closed form expression of the optimum is obtained for the general (m, n) case. The optimum is shown to be unique within the ranges of parameter values valid in practice; its expression is easy to evaluate and shown to be useful to analyze and understand the influence of these parameters. Inspections are assumed to be perfect, i.e. they cause no component failure by themselves and leave no failure undetected. In this sense, the optimum determines a lowest bound for the system failure rate that can be achieved by a system of n-redundant components, m of which require for inspection or maintenance recurrent periods of unavailability of length t. The model and its general closed form solution are believed to be new . Previous work had computed optimal values for an estimation of a time average of system unavailability, but by numerical procedures only and with different numerical approximations, other objectives and model assumptions (one component only inspected at a time), and taking into account failures caused by testing itself, repair and

Reliability Estimation with Uncertainties Consideration for High Power IGBTs in 2.3 MW Wind Turbine Converter System

DEFF Research Database (Denmark)

Kostandyan, Erik; Ma, Ke

2012-01-01

This paper investigates the lifetime of high power IGBTs (insulated gate bipolar transistors) used in large wind turbine applications. Since the IGBTs are critical components in a wind turbine power converter, it is of great importance to assess their reliability in the design phase of the turbine....... Minimum, maximum and average junction temperatures profiles for the grid side IGBTs are estimated at each wind speed input values. The selected failure mechanism is the crack propagation in solder joint under the silicon die. Based on junction temperature profiles and physics of failure model......, the probabilistic and determinist damage models are presented with estimated fatigue lives. Reliably levels were assessed by means of First Order Reliability Method taking into account uncertainties....

Radiation damage in CTR magnet components

International Nuclear Information System (INIS)

Ullmaier, H.

1976-01-01

Data are reviewed (already existing or to be acquired) which should allow prediction of the behavior of large superconducting coils in the radiation field of a future fusion reactor. The electrical and mechanical stability of such magnets is determined by the irradiation induced deterioration of the magnet components, i.e., (a) changes in critical current, field and temperature of the superconductor (NbTi, A-15 phases), (b) resistivity increase in the stabilizer (Cu, Al), and (c) changes in mechanical and dielectric properties of insulators and spacers. Recent low temperature simulation experiments (with fission neutrons and heavy ions) show that the superconductor will not be the critical component of a fusion magnet--at least as far as radiation damage is concerned. Much more severe is the loss of stability due to the resistivity increase of the stabilizing material. It seems, however, that the magnitude of this effect can be predicted rather reliably and therefore taken into account in the coil design. Almost no data exist about the low temperature behavior of insulator and spacer materials in a radiation field. Furthermore, very little is known about the nature of the radiation damage in non-metals, which makes extrapolations of the few existing data to other materials or to other doses highly speculative. Only future experiments can decide if the insulators will be the limiting component of a CTR magnet or not

Reliable, Low-Cost, Low-Weight, Non-Hermetic Coating for MCM Applications

Science.gov (United States)

Jones, Eric W.; Licari, James J.

2000-01-01

Through an Air Force Research Laboratory sponsored STM program, reliable, low-cost, low-weight, non-hermetic coatings for multi-chip-module(MCK applications were developed. Using the combination of Sandia Laboratory ATC-01 test chips, AvanTeco's moisture sensor chips(MSC's), and silicon slices, we have shown that organic and organic/inorganic overcoatings are reliable and practical non-hermetic moisture and oxidation barriers. The use of the MSC and unpassivated ATC-01 test chips provided rapid test results and comparison of moisture barrier quality of the overcoatings. The organic coatings studied were Parylene and Cyclotene. The inorganic coatings were Al2O3 and SiO2. The choice of coating(s) is dependent on the environment that the device(s) will be exposed to. We have defined four(4) classes of environments: Class I(moderate temperature/moderate humidity). Class H(high temperature/moderate humidity). Class III(moderate temperature/high humidity). Class IV(high temperature/high humidity). By subjecting the components to adhesion, FTIR, temperature-humidity(TH), pressure cooker(PCT), and electrical tests, we have determined that it is possible to reduce failures 50-70% for organic/inorganic coated components compared to organic coated components. All materials and equipment used are readily available commercially or are standard in most semiconductor fabrication lines. It is estimated that production cost for the developed technology would range from $1-10/module, compared to $20-200 for hermetically sealed packages.

Sintered tantalum carbide coatings on graphite substrates: Highly reliable protective coatings for bulk and epitaxial growth

Energy Technology Data Exchange (ETDEWEB)

Nakamura, Daisuke; Suzumura, Akitoshi; Shigetoh, Keisuke [Toyota Central R and D Labs., Inc., Nagakute, Aichi 480-1192 (Japan)

2015-02-23

Highly reliable low-cost protective coatings have been sought after for use in crucibles and susceptors for bulk and epitaxial film growth processes involving wide bandgap materials. Here, we propose a production technique for ultra-thick (50–200 μmt) tantalum carbide (TaC) protective coatings on graphite substrates, which consists of TaC slurry application and subsequent sintering processes, i.e., a wet ceramic process. Structural analysis of the sintered TaC layers indicated that they have a dense granular structure containing coarse grain with sizes of 10–50 μm. Furthermore, no cracks or pinholes penetrated through the layers, i.e., the TaC layers are highly reliable protective coatings. The analysis also indicated that no plastic deformation occurred during the production process, and the non-textured crystalline orientation of the TaC layers is the origin of their high reliability and durability. The TaC-coated graphite crucibles were tested in an aluminum nitride (AlN) sublimation growth process, which involves extremely corrosive conditions, and demonstrated their practical reliability and durability in the AlN growth process as a TaC-coated graphite. The application of the TaC-coated graphite materials to crucibles and susceptors for use in bulk AlN single crystal growth, bulk silicon carbide (SiC) single crystal growth, chemical vapor deposition of epitaxial SiC films, and metal-organic vapor phase epitaxy of group-III nitrides will lead to further improvements in crystal quality and reduced processing costs.

Sintered tantalum carbide coatings on graphite substrates: Highly reliable protective coatings for bulk and epitaxial growth

International Nuclear Information System (INIS)

Nakamura, Daisuke; Suzumura, Akitoshi; Shigetoh, Keisuke

2015-01-01

Highly reliable low-cost protective coatings have been sought after for use in crucibles and susceptors for bulk and epitaxial film growth processes involving wide bandgap materials. Here, we propose a production technique for ultra-thick (50–200 μmt) tantalum carbide (TaC) protective coatings on graphite substrates, which consists of TaC slurry application and subsequent sintering processes, i.e., a wet ceramic process. Structural analysis of the sintered TaC layers indicated that they have a dense granular structure containing coarse grain with sizes of 10–50 μm. Furthermore, no cracks or pinholes penetrated through the layers, i.e., the TaC layers are highly reliable protective coatings. The analysis also indicated that no plastic deformation occurred during the production process, and the non-textured crystalline orientation of the TaC layers is the origin of their high reliability and durability. The TaC-coated graphite crucibles were tested in an aluminum nitride (AlN) sublimation growth process, which involves extremely corrosive conditions, and demonstrated their practical reliability and durability in the AlN growth process as a TaC-coated graphite. The application of the TaC-coated graphite materials to crucibles and susceptors for use in bulk AlN single crystal growth, bulk silicon carbide (SiC) single crystal growth, chemical vapor deposition of epitaxial SiC films, and metal-organic vapor phase epitaxy of group-III nitrides will lead to further improvements in crystal quality and reduced processing costs

High-temperature-structural design and research and development for reactor system components

International Nuclear Information System (INIS)

Matsumura, Makoto; Hada, Mikio

1985-01-01

The design of reactor system components requires high-temperature-structural design guide with the consideration of the creep effect of materials related to research and development on structural design. The high-temperature-structural design guideline for the fast prototype reactor MONJU has been developed under the active leadership by Power Reactor and Nuclear Fuel Development Corporation and Toshiba has actively participated to this work with responsibility on in-vessel components, performing research and development programs. This paper reports the current status of high-temperature-structural-design-oriented research and development programs and development of analytical system including stress-evaluation program. (author)

High frequent modelling of a modular multilevel converter using passive components

DEFF Research Database (Denmark)

El-Khatib, Walid Ziad; Holbøll, Joachim; Rasmussen, Tonny Wederberg

2013-01-01

). This means that a high frequency model of the converter has to be designed, which gives a better overview of the impact of high frequency transients etc. The functionality of the model is demonstrated by application to grid connections of off-shore wind power plants. Grid connection of an offshore wind power...... wind power plant employing HVDC. In the present study, a back to back HVDC transmission system is designed in PSCAD/EMTDC. Simulations and results showing the importance of high frequent modeling are presented....... plant using HVDC fundamentally changes the electrical environment for the power plant. Detailed knowledge and understanding of the characteristics and behavior of all relevant power system components under all conditions, including under transients, are required in order to develop reliable offshore...

Leading research on supermetals. Part 3. Small component material; Supermetal no sendo kenkyu. 3. Kogata buzai

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-03-01

The control technology of nanostructure and amorphous structure for small components was studied by literature and patent survey. On nanostructured heat-resistant high-strength materials, a particle dispersion technology by MA method, up-grading technology of steel materials by controlled rolling and oxide metallurgy, and grain refinement technology by phase transformation were extracted. On nanostructured light-weight high-strength malarial, Al base alloy is promising from the viewpoint of resource and energy saving. On amorphous high environment resistant materials, the study on the corrosion resistance of Mo-Ta, Fe-Cr and Ni-Fe alloys is promising. On amorphous magnetic materials, the structure system with an amorphous formability higher than that of previous soft magnetic materials was found. R & D subjects for creating advanced amorphous and nanostructured bulk materials were extracted. Development of supporting technologies for material creation, formation and evaluation is necessary as well as the material design/control technology. 569 refs., 85 figs., 11 tabs.

Next-generation fiber lasers enabled by high-performance components

Science.gov (United States)

Kliner, D. A. V.; Victor, B.; Rivera, C.; Fanning, G.; Balsley, D.; Farrow, R. L.; Kennedy, K.; Hampton, S.; Hawke, R.; Soukup, E.; Reynolds, M.; Hodges, A.; Emery, J.; Brown, A.; Almonte, K.; Nelson, M.; Foley, B.; Dawson, D.; Hemenway, D. M.; Urbanek, W.; DeVito, M.; Bao, L.; Koponen, J.; Gross, K.

2018-02-01

Next-generation industrial fiber lasers enable challenging applications that cannot be addressed with legacy fiber lasers. Key features of next-generation fiber lasers include robust back-reflection protection, high power stability, wide power tunability, high-speed modulation and waveform generation, and facile field serviceability. These capabilities are enabled by high-performance components, particularly pump diodes and optical fibers, and by advanced fiber laser designs. We summarize the performance and reliability of nLIGHT diodes, fibers, and next-generation industrial fiber lasers at power levels of 500 W - 8 kW. We show back-reflection studies with up to 1 kW of back-reflected power, power-stability measurements in cw and modulated operation exhibiting sub-1% stability over a 5 - 100% power range, and high-speed modulation (100 kHz) and waveform generation with a bandwidth 20x higher than standard fiber lasers. We show results from representative applications, including cutting and welding of highly reflective metals (Cu and Al) for production of Li-ion battery modules and processing of carbon fiber reinforced polymers.

Modeling high temperature materials behavior for structural analysis

CERN Document Server

Naumenko, Konstantin

2016-01-01

This monograph presents approaches to characterize inelastic behavior of materials and structures at high temperature. Starting from experimental observations, it discusses basic features of inelastic phenomena including creep, plasticity, relaxation, low cycle and thermal fatigue. The authors formulate constitutive equations to describe the inelastic response for the given states of stress and microstructure. They introduce evolution equations to capture hardening, recovery, softening, ageing and damage processes. Principles of continuum mechanics and thermodynamics are presented to provide a framework for the modeling materials behavior with the aim of structural analysis of high-temperature engineering components.

Dielectric characterization of high-performance spaceflight materials

Science.gov (United States)

Kleppe, Nathan; Nurge, Mark A.; Bowler, Nicola

2015-03-01

As commercial space travel increases, the need for reliable structural health monitoring to predict possible weaknesses or failures of structural materials also increases. Monitoring of these materials can be done through the use of dielectric spectroscopy by comparing permittivity or conductivity measurements performed on a sample in use to that of a pristine sample from 100 μHz to 3 GHz. Fluctuations in these measured values or of the relaxation frequencies, if present, can indicate chemical or physical changes occurring within the material and the possible need for maintenance/replacement. In this work, we establish indicative trends that occur due to changes in dielectric spectra during accelerated aging of various high-performance polymeric materials: ethylene vinyl alcohol (EVOH), Poly (ether ether ketone) (PEEK), polyphenylene sulfide (PPS), and ultra-high molecular weight polyethylene (UHMWPE). Uses for these materials range from electrical insulation and protective coatings to windows and air- or space-craft parts that may be subject to environmental damage over long-term operation. Samples were prepared by thermal exposure and, separately, by ultraviolet/water-spray cyclic aging. The aged samples showed statistically-significant trends of either increasing or decreasing real or imaginary permittivity values, relaxation frequencies, conduction or the appearance of new relaxation modes. These results suggest that dielectric testing offers the possibility of nondestructive evaluation of the extent of age-related degradation in these materials.

Advanced Rankine and Brayton cycle power systems: Materials needs and opportunities

Science.gov (United States)

Grisaffe, S. J.; Guentert, D. C.

1974-01-01

Conceptual advanced potassium Rankine and closed Brayton power conversion cycles offer the potential for improved efficiency over steam systems through higher operating temperatures. However, for utility service of at least 100,000 hours, materials technology advances will be needed for such high temperature systems. Improved alloys and surface protection must be developed and demonstrated to resist coal combustion gases as well as potassium corrosion or helium surface degradation at high temperatures. Extensions in fabrication technology are necessary to produce large components of high temperature alloys. Long time property data must be obtained under environments of interest to assure high component reliability.

Advanced Rankine and Brayton cycle power systems - Materials needs and opportunities

Science.gov (United States)

Grisaffe, S. J.; Guentert, D. C.

1974-01-01

Conceptual advanced potassium Rankine and closed Brayton power conversion cycles offer the potential for improved efficiency over steam systems through higher operating temperatures. However, for utility service of at least 100,000 hours, materials technology advances will be needed for such high temperature systems. Improved alloys and surface protection must be developed and demonstrated to resist coal combustion gases as well as potassium corrosion or helium surface degradation at high temperatures. Extensions in fabrication technology are necessary to produce large components of high temperature alloys. Long-time property data must be obtained under environments of interest to assure high component reliability.

Exploration of reliability databases and comparison of former IFMIF's results

International Nuclear Information System (INIS)

Tapia, Carlos; Dies, Javier; Abal, Javier; Ibarra, Angel; Arroyo, Jose M.

2011-01-01

There is an uncertainty issue about the applicability of industrial databases to new designs, such as the International Fusion Materials Irradiation Facility (IFMIF), as they usually contain elements for which no historical statistics exist. The exploration of common components reliability data in Accelerator Driven Systems (ADS) and Liquid Metal Technologies (LMT) frameworks is the milestone to analyze the data used in IFMIF reliability's reports and for future studies. The comparison between the reliability accelerator results given in the former IFMIF's reports and the databases explored has been made by means of a new accelerator Reliability, Availability, Maintainability (RAM) analysis. The reliability database used in this analysis is traceable.

Dual phase magnetic material component and method of forming

Science.gov (United States)

Dial, Laura Cerully; DiDomizio, Richard; Johnson, Francis

2017-04-25

A magnetic component having intermixed first and second regions, and a method of preparing that magnetic component are disclosed. The first region includes a magnetic phase and the second region includes a non-magnetic phase. The method includes mechanically masking pre-selected sections of a surface portion of the component by using a nitrogen stop-off material and heat-treating the component in a nitrogen-rich atmosphere at a temperature greater than about 900.degree. C. Both the first and second regions are substantially free of carbon, or contain only limited amounts of carbon; and the second region includes greater than about 0.1 weight % of nitrogen.

Structural materials for ITER in-vessel component design

Energy Technology Data Exchange (ETDEWEB)

Kalinin, G. [Max-Planck-Inst. fur Plasmaphys., Garching (Germany). ITER Garching JWS; Gauster, W. [Max-Planck-Inst. fur Plasmaphys., Garching (Germany). ITER Garching JWS; Matera, R. [Max-Planck-Inst. fur Plasmaphys., Garching (Germany). ITER Garching JWS; Tavassoli, A.-A.F. [CEA Centre d`Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France); Rowcliffe, A. [Oak Ridge National Lab., TN (United States); Fabritsiev, S. [Research Inst. of Electrophysical Apparatus, St. Petersburg (Russian Federation); Kawamura, H. [JAERI, IMTR Project, Ibaraki (Japan). Blanket Irradiation Lab.

1996-10-01

The materials proposed for ITER in-vessel components have to exhibit adequate performance for the operating lifetime of the reactor or for specified replacement intervals. Estimates show that maximum irradiation dose to be up to 5-7 dpa (for 1 MWa/m{sup 2} in the basic performance phase (BPP)) within a temperature range from 20 to 300 C. Austenitic SS 316LN-ITER Grade was defined as a reference option for the vacuum vessel, blanket, primary wall, pipe lines and divertor body. Conventional technologies and mill products are proposed for blanket, back plate and manifold manufacturing. HIPing is proposed as a reference manufacturing method for the primary wall and blanket and as an option for the divertor body. The existing data show that mechanical properties of HIPed SS are no worse than those of forged 316LN SS. Irradiation will result in property changes. Minimum ductility has been observed after irradiation in an approximate temperature range between 250 and 350 C, for doses of 5-10 dpa. In spite of radiation-induced changes in tensile deformation behavior, the fracture remains ductile. Irradiation assisted corrosion cracking is a concern for high doses of irradiation and at high temperatures. Re-welding is one of the critical issues because of the need to replace failed components. It is also being considered for the replacement of shielding blanket modules by breeding modules after the BPP. (orig.).

Uncertainty propagation and sensitivity analysis in system reliability assessment via unscented transformation

International Nuclear Information System (INIS)

Rocco Sanseverino, Claudio M.; Ramirez-Marquez, José Emmanuel

2014-01-01

The reliability of a system, notwithstanding it intended function, can be significantly affected by the uncertainty in the reliability estimate of the components that define the system. This paper implements the Unscented Transformation to quantify the effects of the uncertainty of component reliability through two approaches. The first approach is based on the concept of uncertainty propagation, which is the assessment of the effect that the variability of the component reliabilities produces on the variance of the system reliability. This assessment based on UT has been previously considered in the literature but only for system represented through series/parallel configuration. In this paper the assessment is extended to systems whose reliability cannot be represented through analytical expressions and require, for example, Monte Carlo Simulation. The second approach consists on the evaluation of the importance of components, i.e., the evaluation of the components that most contribute to the variance of the system reliability. An extension of the UT is proposed to evaluate the so called “main effects” of each component, as well to assess high order component interaction. Several examples with excellent results illustrate the proposed approach. - Highlights: • Simulation based approach for computing reliability estimates. • Computation of reliability variance via 2n+1 points. • Immediate computation of component importance. • Application to network systems