Aeronautical Engineering: A special bibliography with indexes, supplement 54

This bibliography lists 316 reports, articles, and other documents introduced into the NASA scientific and technical information system in January 1975

Index to NASA Tech Briefs, 1975

This index contains abstracts and four indexes--subject, personal author, originating Center, and Tech Brief number--for 1975 Tech Briefs

General Synthesis Report of the Different ADS Design Status. Establishment of a Catalogue of the R&D needs

This document is a General Synthesis Report of the Different ADS Design Status being designed within the EUROTRANS Integrated Project; an FP6 European commission partially funded programme. This project had the goal to demonstrate the possibility of nuclear waste transmutation/burning in Accelerator Driven Systems (ADS) at industrial scale.The focus is on a Pb-cooled ADS for the European Facility on Industrial scale Transmuter (ETD/EFIT) with a back-up solution based on an He cooled ADS.As an intermediate step towards this industrial-scale prototype, an eXperimental Transmuter based on ADS concept (ETD/XT-ADS) able to demonstrate both the feasibility of the ADS concept and to accumulate experience when using dedicated fuel sub-assemblies or dedicated pins within a MOX fuel core has been also studied.The two machines (XT-ADS and Pb cooled EFIT) have been designed in a consistent way bringing more credibility to the potential licensing of these plants and with sufficient details to allow definition of the critical issues as regards design, safety and associated technological and basic R&D needs. The different designs fit rather well with the technical objectives fixed at the beginning of the project in consistency with the European Roadmap on ADS development.For what concerns the accelerator, the superconducting LINAC has been clearly assessed as the most suitable concept for the three reactors in particular with respect to the stringent requirements on reliability. Associated R&D needs have been identified and will be focused on critical components (injector, cryomodule) long term testing.The design of the different ADS has been performed in view of what is reasonably achievable pending the completion of R&D programmes. The way the EUROTRANS Integrated Project has been organised with other domains than the DM1 Design being specifically devoted to R&D tasks in support to the overall ETD/EFIT and ETD/XT-ADS design tasks has been helpful. The other domains were centred on the assessment of reactivity measurement techniques (DM2 ECATS), on the development of U-free dedicated fuels (DM3 AFTRA), on materials behaviour and heavy liquid metal technology (DM4 DEMETRA) and on nuclear data assessment (DM5 NUDATRA). Pending questions associated to technology gaps have been identified through the different appropriate R&D work programmes and a Catalogue of the R&D needs has been established.Finally, the work within the EUROTRANS integrated project has provided an overall assessment of the feasibility at a reasonable cost for an ADS based transmutation so that a decision can be taken to launch a detailed design and construction of the intermediate step Experimental ADS now already launched within the 7th FP programme under the name of Common Design Team (CDT)

Workshop on an Assessment of Gas-Side Fouling in Fossil Fuel Exhaust Environments

The state of the art of gas side fouling in fossil fuel exhaust environments was assessed. Heat recovery applications were emphasized. The deleterious effects of gas side fouling including increased energy consumption, increased material losses, and loss of production were identified

Scientific Assessment in support of the Materials Roadmap enabling Low Carbon Energy Technologies: Technology Nuclear Energy

This scientific assessment serves as the basis for a materials research roadmap for the nuclear fission technology, itself an integral element of an overall "Materials Roadmap Enabling Low Carbon Technologies", a Commission Staff Working Document published in December 2011. The Materials Roadmap aims at contributing to strategic decisions on materials research funding at European and Member State levels and is aligned with the priorities of the Strategic Energy Technology Plan (SET-Plan). It is intended to serve as a guide for developing specific research and development activities in the field of materials for energy applications over the next 10 years. This report provides an in-depth analysis of the state-of-the-art and future challenges for energy technology-related materials and the needs for research activities to support the development of nuclear fission technology both for the 2020 and the 2050 market horizons. It has been produced by independent and renowned European materials scientists and energy technology experts, drawn from academia, research institutes and industry, under the coordination the SET-Plan Information System (SETIS), which is managed by the Joint Research Centre (JRC) of the European Commission. The contents were presented and discussed at a dedicated hearing in which a wide pool of stakeholders participated, including representatives of the relevant technology platforms, industry associations and the Joint Programmes of the European Energy Research Associations.JRC.F.4-Safety of future nuclear reactor

A life assessment methodology for heat exchanger and steam generator tubing

The development of an accurate technique for the service life prediction of steam generator tubes is influenced by two major problems in practice. These are: (1) availability of limited information regarding the in-service conditions of the tubes and (2) effects of material aging and degradation resulting from service exposure. In an attempt to solve the above problems, this dissertation research focused on the development of a model-based methodology for the life assessment of steam generator tubes subjected to a certain degradation process. The methodology combines engineering analysis of the degradation process under study with the analysis of process field data and information to establish semi-empirical models to forecast the future trend in the degradation. The projection of this trend to a pre-defined allowable degradation level was used to determine the life expectancy of the component. The salient feature of this methodology is in its capacity to recognize the process nonlinearities and to identify the correct process trends which cannot be detected by simple applications of traditional forecasting techniques. This capacity greatly reduces the amount of required field data for a good forecast. The semi-empirical prediction models were developed using both parametric and non-parametric techniques. The functional forms of the parametric models were determined based on both the approximated physics of the degradation process and the availability of field data for a reliable estimation of the model parameters. To improve the model prediction, the unknown process dynamics were enhanced by the incorporation of an empirical dynamic formulation of field data. The non-parametric models were established based on artificial neural network techniques. The neural network prediction (NNP) models were trained with a wide range of possible degradation paths generated by the process model. The trained NNP models perform an intelligent data mapping to match the trends in the input data to one of the learned process paths and thereby forecasting the future trends of the process within a specified time-frame. The proposed life assessment approach was used to predict the wear process of a Once-Through Steam Generator (OTSG) tube within its 15th tube support as a complex application of trend forecasting. To implement the methodology, a tube wear process model was developed to simulate the process trend over time with regard to aging and degradation mechanisms resulting from service exposure. The simulated wear data were used to establish various semi-empirical prediction models to determine suitable models for process trend prediction with different block sizes of data. The results show the degradation of friction coefficient and material aging could markedly increase the rate of tube wear with subsequent tube life reduction. They also indicated that the power-exponential model [atbexp(ct)], developed based on this methodology, provided a more accurate prediction of the tube life than the power-law model (atb) suggested in the literature. A significant improvement in the prediction of the power-law model was obtained by including a dynamic formulation of the historical data. The results also demonstrated that NNP models perform extremely well for both trend recognition and prediction, even with a limited amount of data. An attractive feature of NNP models is that they are far less noise-sensitive than parametric models. The estimation of residual life of tubing was demonstrated using both parametric and NNP models. The methodology developed in this research is generic in nature and can be applied to the life assessment of both stationary components and rotating machinery

Theoretical and Experimental Study of Degradation Monitoring of Steam Generators and Heat Exchangers

The objective of this research is focused on the modeling, analysis, and experimental study of steam generator and heat exchanger degradation monitoring and fault diagnosis. Experimental and analytical studies of tube fouling are performed and the system-level degradations are monitored using data-driven modeling of heat exchanger measurements. Initially, a comprehensive literature study was made on the steam generator and heat exchanger degradation types and mechanisms, including fouling and corrosion. Based on the mass balance, energy balance, and momentum balance and the moving-boundary method, a multi-node SIMULINK model of a U-tube steam generator (UTSG) has been developed so as to simulate the UTSG dynamics or responses to various defects, including fouling. UTSG responses to different events, such as reduced heat transfer area, change in heat transfer coefficient at different axial nodes, change in tube material conductivity, and the change of steam valve coefficients have been simulated and studied using the SIMULINK model. A mathematical model is established and implemented in MATLAB based on a systematic literature review of steam generator and heat exchanger fouling. The fouling model and the UTSG SIMULINK model are both used to study the progression of tube fouling and the effects on UTSG thermal performance. The simulation results show the fidelity and validity of the developed models. The developed models can be used to predict the time behavior of UTSG thermal performance. This could provide guidance for plant maintenance planning. The simulation results of fouling and its effect on UTSG thermal performance are presented. Based on an existing heat exchanger laboratory system, an experimental study of the particulate fouling progression in a heat exchanger has been performed. The results show the particulate fouling in heat exchangers also exhibits an asymptotic behavior, and the model-based method for fouling monitoring and diagnosis is successful and efficient. Finally a theoretical heat exchanger model is developed and coded using MATLAB. This model is then used to generate data representative of normal conditions. With these normal data and the fouling data collected from the experimental loop, the Group Method of Data Handling (GMDH) method is then used to monitor and diagnose the fouling problem in the heat exchanger. The GMDH results show that the residuals of both hot-side and cold-side outlet temperatures follow the same pattern as the overall thermal resistance obtained from the experiment. Also, the UTSG SIMULINK model is used to generate data and the GMDH method is used to establish a data-driven model. The results again show that the GMDH approach can appropriately model the UTSG system behavior and can be used for fouling monitoring and diagnosis and also model the effect of tube plugging on UTSG steam pressure. These results demonstrate that an appropriately developed GMDH model can be used to monitor and diagnose the fouling, and possibly other degradation problems in both the heat exchanger and steam generator systems

A PROBABILISTIC MECHANISTIC APPROACH FOR ASSESSING THE RUPTURE FREQUENCY OF SMALL MODULAR REACTOR STEAM GENERATOR TUBES USING UNCERTAIN INPUTS FROM IN-SERVICE INSPECTIONS

One of the significant safety issues in nuclear power plants is the rupture of steam generator tubes leading to the loss of radioactive primary coolant inventory and establishment of a path that would bypass the plant's containment structure. Frequency of steam generator tube ruptures is required in probabilistic safety assessments of pressurized water reactors to determine the risks of radionuclide release. The estimation of this frequency has traditionally been based on non-homogeneous historical data that are not applicable to small modular reactors consisting of new steam generator designs. In this research a probabilistic mechanistic-based approach has been developed for assessing the frequency of steam generator tube ruptures. Physics-of-failure concept has been used to formulate mechanistic degradation models considering the underlying degradation conditions prevailing in steam generators. Uncertainties associated with unknown or partially known factors such as material properties, manufacturing methods, and model uncertainties have been characterized, and considered in the assessment of rupture frequency. An application of the tube rupture frequency assessment approach has been demonstrated for tubes of a typical helically-coiled steam generator proposed in most of the new small modular reactors. The tube rupture frequency estimated through the proposed approach is plant-specific and more representative for use in risk-informed safety assessment of small modular reactors. Information regarding the health condition of steam generator tubes from in-service inspections may be used to update the pre-service estimates of tube rupture frequency. In-service inspection data are uncertain in nature due to detection uncertainties and measurement errors associated with nondestructive evaluation methods, which if not properly accounted for, can result in over- or under-estimation of tube rupture frequency. A Bayesian probabilistic approach has been developed in this research that combines prior knowledge on defects with uncertain in-service inspection data, considering all the associated uncertainties to give a probabilistic description of the real defect size and density in the tubes. An application of the proposed Bayesian approach has been provided. Defect size and density estimated through the proposed Bayesian approach can be used to update the pre-service estimates of tube rupture frequency, in order to support risk-informed maintenance and regulatory decision-making