Download or read book Methods for Quantifying Uncertainty in Fast Reactor Analyses written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Liquid-metal-cooled fast reactors in the form of sodium-cooled fast reactors have been successfully built and tested in the U.S. and throughout the world. However, no fast reactor has operated in the U.S. for nearly fourteen years. More importantly, the U.S. has not constructed a fast reactor in nearly 30 years. In addition to reestablishing the necessary industrial infrastructure, the development, testing, and licensing of a new, advanced fast reactor concept will likely require a significant base technology program that will rely more heavily on modeling and simulation than has been done in the past. The ability to quantify uncertainty in modeling and simulations will be an important part of any experimental program and can provide added confidence that established design limits and safety margins are appropriate. In addition, there is an increasing demand from the nuclear industry for best-estimate analysis methods to provide confidence bounds along with their results. The ability to quantify uncertainty will be an important component of modeling that is used to support design, testing, and experimental programs. Three avenues of UQ investigation are proposed. Two relatively new approaches are described which can be directly coupled to simulation codes currently being developed under the Advanced Simulation and Modeling program within the Reactor Campaign. A third approach, based on robust Monte Carlo methods, can be used in conjunction with existing reactor analysis codes as a means of verification and validation of the more detailed approaches.

Download or read book Uncertainty Quantification and Propagation Methodology for Steady State Safety Analysis of Lead cooled Fast Reactors written by Ishita Trivedi and published by . This book was released on 2020 with total page 59 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Uncertainty Quantification and Propagation Methodology for Safety Analysis of Lead cooled Fast Reactors written by Ishita Trivedi and published by . This book was released on 2021 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Comparison of Uncertainty Quantification Methods for Fast Reactor Neutronics written by and published by . This book was released on 2010 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Uncertainty Quantification Approaches for Advanced Reactor Analyses written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The original approach to nuclear reactor design or safety analyses was to make very conservative modeling assumptions so as to ensure meeting the required safety margins. Traditional regulation, as established by the U.S. Nuclear Regulatory Commission required conservatisms which have subsequently been shown to be excessive. The commission has therefore moved away from excessively conservative evaluations and has determined best-estimate calculations to be an acceptable alternative to conservative models, provided the best-estimate results are accompanied by an uncertainty evaluation which can demonstrate that, when a set of analysis cases which statistically account for uncertainties of all types are generated, there is a 95% probability that at least 95% of the cases meet the safety margins. To date, nearly all published work addressing uncertainty evaluations of nuclear power plant calculations has focused on light water reactors and on large-break loss-of-coolant accident (LBLOCA) analyses. However, there is nothing in the uncertainty evaluation methodologies that is limited to a specific type of reactor or to specific types of plant scenarios. These same methodologies can be equally well applied to analyses for high-temperature gas-cooled reactors and to liquid metal reactors, and they can be applied to steady-state calculations, operational transients, or severe accident scenarios. This report reviews and compares both statistical and deterministic uncertainty evaluation approaches. Recommendations are given for selection of an uncertainty methodology and for considerations to be factored into the process of evaluating uncertainties for advanced reactor best-estimate analyses.

Download or read book Efficient Uncertainty Quantification for a Fast Spectrum Generation IV Reactor System written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This research is part of on-going research on the management of uncertainties in simulator predictions for Generation IV systems via optimum experimental design. The focus is on uncertainties originating due to input data. The objective is to devise an algorithmic framework for quantification of uncertainties, identification of their key sources, and ultimately guiding the design of validating experiments for their reduction. An integral part of this research is the development of uncertainty quantification algorithms for models involving many input data and output responses. This represents the focus of the research reported here. Uncertainty Quantification (UQ) in nuclear systems simulation is playing an increasing role in supporting decisions related to the research and development of advanced nuclear energy systems, especially those of interest to the Global Nuclear Energy Partnership (GNEP) and Next Generation Nuclear Plant (NGNP) programs. UQ will help assess the adequacy of existing simulation tools and associated databases, e.g. nuclear cross-section data, and provide guidance to areas of models and/or data where further development and/or measurements should be prioritized. A sensitivity and uncertainty analysis has been conducted to study the effects of neutron microscopic cross-section data uncertainty on macroscopic attributes that influence reactor core design, performance and safety for a Generation IV reactor concept. In the realm of reactor engineering, neutron cross-section data represents the basic physics of neutron interactions with matter and therefore have large impacts on evolution of flux, power, reactivity and other reactor performance attributes. Currently, we focus on uncertainties originating from cross-section data uncertainties, believed to be of primary significance for fast reactor calculations. This thesis presents a recent development of an UQ algorithm for increasing the efficiency of UQ to a level that enables its execution on a r.

Download or read book Quantifying Time dependent Uncertainty in the BEAVRS Benchmark Using Time Series Analysis written by Shikhar Kumar (S. M.) and published by . This book was released on 2018 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in computational capabilities have enabled the development of high-fidelity methods for large-scale modeling of nuclear reactors. However, such techniques require proper benchmarking and validation to ensure correct and consistent modeling of real problems. Thus, the BEAVRS benchmark was developed to legitimize the advancements of new 3-D full-core algorithms in the field of reactor physics. However, in order to address the issue of BEAVRS uncertainty quantification (UQ) of Uranium-235 fission reaction rate data, this thesis proposes a new method for measuring uncertainty that goes beyond merely conducting statistical analysis of multiple measurements at one given point in time. Instead, this work hinges on principles of time series analysis and develops a rigorous method for quantifying the uncertainty in using \tilt-corrected" data in an attempt to evaluate time-dependent uncertainty. Such efforts show consistent results across the four dierent methods and will ultimately assist in demonstrating that BEAVRS is a non-proprietary international benchmark for the validation of high-fidelity tools.

Download or read book Advances in Fast Reactor Sensitivity and Uncertainty Analysis written by and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A review of present methods and existing computer codes indicates an enormous capability not only to calculate sensitivity coefficients but also to apply them to a variety of purposes. However, there are still many limitations to our present capabilities. One of these limitations has been our inability to include in a complete and systematic way the effect of methods uncertainties on the determination of adjusted data, which depends, in general, not only on experimental measurements, but also on estimates of covariances associated with the measurements and the methods. Also, the uncertainty in adjusted data contains contributions from uncertainties in covariance estimates which contributions we have heretofore neglected. A new and comprehensive approach to include effects of methods uncertainties is presented here, and all sources which contribute to the uncertainty of the adjusted data are considered. This new approach is demonstrated using rough estimates for the methods uncertainties as applied to a simplified representation of the ZPR-6/7 fast benchmark. The results indicate that it may be essential to include methods uncertainties if integral experiments are to be used for the creation of adjusted nuclear data libraries. A careful evaluation of methods bias and uncertainties must still be performed.

Download or read book Reactor Physics Methods and Applications written by Tengfei Zhang and published by Frontiers Media SA. This book was released on 2022-06-29 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Uncertainty Quantification for Safety Verification Applications in Nuclear Power Plants written by Emmanuel Boafo and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is an increasing interest in computational reactor safety analysis to systematically replace the conservative calculations by best estimate calculations augmented by quantitative uncertainty analysis methods. This has been necessitated by recent regulatory requirements that have permitted the use of such methods in reactor safety analysis. Stochastic uncertainty quantification methods have shown great promise, as they are better suited to capture the complexities in real engineering problems. This study proposes a framework for performing uncertainty quantification based on the stochastic approach, which can be applied to enhance safety analysis. Additionally, risk level has increased with the degradation of Nuclear Power Plant (NPP) equipment and instrumentation. In order to achieve NPP safety, it is important to continuously evaluate risk for all potential hazards and fault propagation scenarios and map protection layers to fault / failure / hazard propagation scenarios to be able to evaluate and verify safety level during NPP operation. In this study, the Fault Semantic Network (FSN) methodology is proposed. This involved the development of static and dynamic fault semantic network (FSN) to model possible fault propagation scenarios and the interrelationships among associated process variables. The proposed method was demonstrated by its application to two selected case studies. The use of FSN is essential for fault detection, understanding fault propagation scenarios and to aid in the prevention of catastrophic events. Two transient scenarios were simulated with a best estimate thermal hydraulic code, CATHENA. Stochastic uncertainty quantification and sensitivity analyses were performed using the OPENCOSSAN software which is based on the Monte Carlo method. The effect of uncertainty in input parameters were investigated by analyzing the probability distribution of output parameters. The first four moments (mean, variance, skewness and kurtosis) of the output parameters were computed and analyzed. The uncertainty in output pressure was 0.61% and 0.57% was found for the mass flow rate in the Edward's blowdown transient. An uncertainty of 0.087% was obtained for output pressure and 0.048% for fuel pin temperature in the RD-14 test case. These results are expected to be useful for providing insight into safety margins related to safety analysis and verification.

Download or read book Handbook of Generation IV Nuclear Reactors written by Igor Pioro and published by Woodhead Publishing. This book was released on 2022-12-07 with total page 1112 pages. Available in PDF, EPUB and Kindle. Book excerpt: Handbook of Generation IV Nuclear Reactors, Second Edition is a fully revised and updated comprehensive resource on the latest research and advances in generation IV nuclear reactor concepts. Editor Igor Pioro and his team of expert contributors have updated every chapter to reflect advances in the field since the first edition published in 2016. The book teaches the reader about available technologies, future prospects and the feasibility of each concept presented, equipping them users with a strong skillset which they can apply to their own work and research. - Provides a fully updated, revised and comprehensive handbook dedicated entirely to generation IV nuclear reactors - Includes new trends and developments since the first publication, as well as brand new case studies and appendices - Covers the latest research, developments and design information surrounding generation IV nuclear reactors

Download or read book Neutron Physics written by Karl-Heinrich Beckurts and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 455 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is based upon a series of lectures I have occasionally given at the University of Gottingen since 1951. They were meant to introduce the students of experimental physics to the work in a neutron physics laboratory dealing with the problem of measuring neutron flux, diffusion length, Fermi age, effective neutron temperature, absorption cross sections and similar problems. Moreover, these lectures were intended to prepare the students for a subsequent lecture covering the physics of nuclear reactors. The original character of this series of lectures has been retained in the book. It is intended for use by students as well as anyone desiring to work on neutron physics measurements. The first half mainly covers the theory of neutron fields, i. e. essentially diffusion and slowing down theory. The second half is largely concerned with measurements in neutron fields. The appendix contains information and data which, in our experience, are frequently required in a neutron laboratory. The field of nuclear physics proper is briefly touched upon in the first two chapters, but only to the extent necessary for the understanding of the following chapters. The multitude of applications of neutron radiation has not been covered. The conclusion of this manuscript coincided with the end of my long period of activity with the Max-Planck-Institut fur Physik at Gottingen. To Professor HEISENBERG lowe thanks for his advice and suggestions for many of the subjects treated here.

Download or read book Methods and Computer Codes for Probabilistic Sensitivity and Uncertainty Analysis written by J. K. Vaurio and published by . This book was released on 1984 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Accelerator Driven System at Kyoto University Critical Assembly written by Cheol Ho Pyeon and published by Springer. This book was released on 2021-03-20 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book is a unique compilation of experimental benchmark analyses of the accelerator-driven system (ADS) at the Kyoto University Critical Assembly (KUCA) on the most recent advances in the development of computational methods. It is devoted especially to nuclear engineers and scientists. Readers will find a detailed description of advanced measurement techniques and calculation methodologies for the ADS with 14 MeV neutrons and high-energy neutrons (with combined use of 100 MeV protons and Pb-Bi target) at KUCA. Additionally, experimental results of nuclear transmutation of minor actinides by ADS and at a critical state are included. Readers also have access to benchmarks of specific ADS experiments with raw data in the Appendix. The book is a valuable resource for the ADS experiments at KUCA which are globally recognized as both static and kinetic studies from the point of view of fundamental research.

Download or read book Nuclear Systems Volume II written by Neil E. Todreas and published by CRC Press. This book was released on 2021-12-13 with total page 659 pages. Available in PDF, EPUB and Kindle. Book excerpt: Discusses fundamental ideas for various modeling approaches for the macro- and micro-scale flow conditions in the reactor. Covers specific design considerations, such as natural convection and core reliability. Enables the reader to better understand the importance of safety considerations in thermal engineering and analysis of a modern nuclear plant. Features end-of-chapter problems. Includes a Solutions Manual for adopting instructors.

Download or read book Spectral Methods for Uncertainty Quantification written by Olivier Le Maitre and published by Springer Science & Business Media. This book was released on 2010-03-11 with total page 542 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book deals with the application of spectral methods to problems of uncertainty propagation and quanti?cation in model-based computations. It speci?cally focuses on computational and algorithmic features of these methods which are most useful in dealing with models based on partial differential equations, with special att- tion to models arising in simulations of ?uid ?ows. Implementations are illustrated through applications to elementary problems, as well as more elaborate examples selected from the authors’ interests in incompressible vortex-dominated ?ows and compressible ?ows at low Mach numbers. Spectral stochastic methods are probabilistic in nature, and are consequently rooted in the rich mathematical foundation associated with probability and measure spaces. Despite the authors’ fascination with this foundation, the discussion only - ludes to those theoretical aspects needed to set the stage for subsequent applications. The book is authored by practitioners, and is primarily intended for researchers or graduate students in computational mathematics, physics, or ?uid dynamics. The book assumes familiarity with elementary methods for the numerical solution of time-dependent, partial differential equations; prior experience with spectral me- ods is naturally helpful though not essential. Full appreciation of elaborate examples in computational ?uid dynamics (CFD) would require familiarity with key, and in some cases delicate, features of the associated numerical methods. Besides these shortcomings, our aim is to treat algorithmic and computational aspects of spectral stochastic methods with details suf?cient to address and reconstruct all but those highly elaborate examples.

Download or read book Energy Research Abstracts written by and published by . This book was released on 1993 with total page 754 pages. Available in PDF, EPUB and Kindle. Book excerpt: