Download or read book Passive Safety Systems in Advanced Water Cooled Reactors Awcrs Case Studies written by International Atomic Energy Agency and published by International Atomic Energy Agency. This book was released on 2013-10-31 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This publication is the final report of the INPRO collaborative project on advanced water cooled reactor (AWCR) case studies in support of passive safety systems. It compiles case study results on natural circulation and thermal stratification phenomena in selected passive safety systems performed by the participating countries of Argentina, India and Republic of Korea. The publication presents case study results as well as major findings and conclusions drawn from these case studies. This publication will be a useful resource for researchers in the area of core physics and reactor thermohydraulics and for technical experts and engineers engaged in experimental investigation and theoretical simulation for developing passive safety systems."--Publisher's description.

Download or read book Passive Safety Systems in Advanced Water Cooled Reactors AWCRs written by and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This publication is the final report of the INPRO collaborative project on advanced water cooled reactor (AWCR) case studies in support of passive safety systems. It compiles case study results on natural circulation and thermal stratification phenomena in selected passive safety systems performed by the participating countries of Argentina, India and Republic of Korea. The publication presents case study results as well as major findings and conclusions drawn from these case studies. This publication will be a useful resource for researchers in the area of core physics and reactor thermohydraulics and for technical experts and engineers engaged in experimental investigation and theoretical simulation for developing passive safety systems."--Publisher's description.

Download or read book Passive Safety Systems and Natural Circulation in Water Cooled Nuclear Power Plants written by and published by . This book was released on 2009 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the mid-1980s there has been much discussion of the advantages of passive safety systems in advanced nuclear power plants (NPPs). It has been recognized that the application of passive safety systems can contribute to simplification and potentially improve economics of new NPP designs. However, this implies careful design and analysis methods to assure that these systems perform their intended functions. This publication draws on the studies of an IAEA coordinated research project on the topic and reports the findings of the latest research activities. It describes passive safety systems in a wide range of advanced water-cooled nuclear power plant designs, defines the thermal hydraulic phenomena associated with natural circulation phenomena and cross-links these phenomena with the passive safety systems.

Download or read book Passive Safety Systems in Water Cooled Reactors written by International Atomic Energy Agency and published by . This book was released on 2019 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Impact of Passive Safety Systems on Desirability of Advanced Light Water Reactors written by Ryan C. Eul and published by . This book was released on 2006 with total page 368 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work investigates whether the advanced light water reactor designs with passive safety systems are more desirable than advanced reactor designs with active safety systems from the point of view of uncertainty in the performance of safety systems as well as the economic implications of the passive safety systems. Two advanced pressurized water reactors and two advanced boiling water reactors, one representing passive reactors and the other active reactors for each type of coolant, are compared in terms of operation and responses to accidents as reported by the vendors. Considering a simplified decay heat removal system that utilizes an isolation condenser for decay heat removal, the uncertainty in the main parameters affecting the system performance upon a reactor isolation accident is characterized when the system is to rely on natural convection and when it is to rely on a pump to remove the core heat. It is found that the passive system is less certain in its performance if the pump of the active system is tested at least once every five months. In addition, a cost model is used to evaluate the economic differences and benefits between the active and passive reactors. It is found that while the passive systems could have the benefit of fewer components to inspect and maintain during operation, they do suffer from a larger uncertainty about the time that would be required for their licensing due to more limited data on the reliability of their operation. Finally, a survey among nuclear energy experts with a variety of affiliations was conducted to determine the current professional attitude towards these two competing nuclear design options. The results of the survey show that reactors with passive safety systems are more desirable among the surveyed expert groups. The perceived advantages of passive systems are an increase in plant safety with a decrease in cost.

Download or read book Study of Cost Effective Large Advanced Pressurized Water Reactors that Employ Passive Safety Features written by Y. Hayashi and published by . This book was released on 2003 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: A report of DOE sponsored portions of AP1000 Design Certification effort. On December 16, 1999, The United States Nuclear Regulatory Commission issued Design Certification of the AP600 standard nuclear reactor design. This culminated an 8-year review of the AP600 design, safety analysis and probabilistic risk assessment. The AP600 is a 600 MWe reactor that utilizes passive safety features that, once actuated, depend only on natural forces such as gravity and natural circulation to perform all required safety functions. These passive safety systems result in increased plant safety and have also significantly simplified plant systems and equipment, resulting in simplified plant operation and maintenance. The AP600 meets NRC deterministic safety criteria and probabilistic risk criteria with large margins. A summary comparison of key passive safety system design features is provided in Table 1. These key features are discussed due to their importance in affecting the key thermal-hydraulic phenomenon exhibited by the passive safety systems in critical areas. The scope of some of the design changes to the AP600 is described. These changes are the ones that are important in evaluating the passive plant design features embodied in the certified AP600 standard plant design. These design changes are incorporated into the AP1000 standard plant design that Westinghouse is certifying under 10 CFR Part 52. In conclusion, this report describes the results of the representative design certification activities that were partially supported by the Nuclear Energy Research Initiative. These activities are unique to AP1000, but are representative of research activities that must be driven to conclusion to realize successful licensing of the next generation of nuclear power plants in the United States.

Download or read book Design and Transient Analysis of Passive Safety Cooling Systems for Advanced Nuclear Reactors written by Cristhian Galvez and published by . This book was released on 2011 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Pebble Bed Advanced High Temperature Reactor (PB-AHTR) is a pebble fueled, liquid salt cooled, high temperature nuclear reactor design that can be used for electricity generation or other applications requiring the availability of heat at elevated temperatures. A stage in the design evolution of this plant requires the analysis of the plant during a variety of potential transients to understand the primary and safety cooling system response. This study focuses on the performance of the passive safety cooling system with a dual purpose, to assess the capacity to maintain the core at safe temperatures and to assist the design process of this system to achieve this objective. The analysis requires the use of complex computational tools for simulation and verification using analytical solutions and comparisons with experimental data. This investigation builds upon previous detailed design work for the PB-AHTR components, including the core, reactivity control mechanisms and the intermediate heat exchanger, developed in 2008. In addition the study of this reference plant design employs a wealth of auxiliary information including thermal-hydraulic physical phenomena correlations for multiple geometries and thermophysical properties for the constituents of the plant. Finally, the set of performance requirements and limitations imposed from physical constrains and safety considerations provide with a criteria and metrics for acceptability of the design. The passive safety cooling system concept is turned into a detailed design as a result from this study. A methodology for the design of air-cooled passive safety systems was developed and a transient analysis of the plant, evaluating a scrammed loss of forced cooling event was performed. Furthermore, a design optimization study of the passive safety system and an approach for the validation and verification of the analysis is presented. This study demonstrates that the resulting point design responds properly to the transient event and maintains the core and reactor components at acceptable temperatures within allowable safety margins. It is also demonstrated that the transition from steady full-power, forced-cooling mode to steady decay-heat, natural-circulation mode is stable, predictable and well characterized.

Download or read book A review of the passive safety features of advanced water reactor designs written by AEA Technology: Safety and Reliability Directorate and published by . This book was released on 1990 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Identification and Characterization of Passive Safety System and Inherent Safety Feature Building Blocks for Advanced Light water Reactors written by and published by . This book was released on 1989 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Oak Ridge National Laboratory (ORNL) is investigating passive and inherent safety options for Advanced Light-Water Reactors (ALWRs). A major activity in 1989 includes identification and characterization of passive safety system and inherent safety feature building blocks, both existing and proposed, for ALWRs. Preliminary results of this work are reported herein. This activity is part of a larger effort by the US Department of Energy, reactor vendors, utilities, and others in the United States to develop improved LWRs. The Advanced Boiling Water Reactor (ABWR) program and the Advanced Pressurized Water Reactor (APWR) program have as goals improved, commercially available LWRs in the early 1990s. The Advanced Simplified Boiling Water Reactor (ASBWR) program and the AP-600 program are developing more advanced reactors with increased use of passive safety systems. It is planned that these reactors will become commercially available in the mid 1990s. The ORNL program is an exploratory research program for LWRs beyond the year 2000. Desired long-term goals for such reactors include: (1) use of only passive and inherent safety, (2) foolproof against operator errors, (3) malevolence resistance against internal sabotage and external assault and (4) walkaway safety. The acronym ''PRIME'' (Passive safety, Resilient operation, Inherent safety, Malevolence resistance, and Extended (walkaway) safety) is used to summarize these desired characteristics. Existing passive and inherent safety options are discussed in this document.

Download or read book Providing the Basis for Innovative Improvements in Advanced LWR Reactor Passive Safety Systems Design written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This project characterizes typical two-phase stratified flow conditions in advanced water reactor horizontal pipe sections, following activation of passive cooling systems. It provides (1) a means to educate nuclear engineering students regarding the importance of two-phase stratified flow in passive cooling systems to the safety of advanced reactor systems and (2) describes the experimental apparatus and process to measure key parameters essential to consider when designing passive emergency core cooling flow paths that may encounter this flow regime. Based on data collected, the state of analysis capabilities can be determined regarding stratified flow in advanced reactor systems and the best paths forward can be identified to ensure that the nuclear industry can properly characterize two-phase stratified flow in passive emergency core cooling systems.

Download or read book Experimental Validation of Passive Safety System Models written by Nicolas Zweibaum and published by . This book was released on 2015 with total page 231 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of advanced nuclear reactor technology requires understanding of complex, integrated systems that exhibit novel phenomenology under normal and accident conditions. The advent of passive safety systems and enhanced modular construction methods requires the development and use of new frameworks to predict the behavior of advanced nuclear reactors, both from a safety standpoint and from an environmental impact perspective. This dissertation introduces such frameworks for scaling of integral effects tests for natural circulation in fluoride-salt-cooled, high-temperature reactors (FHRs) to validate evaluation models (EMs) for system behavior; subsequent reliability assessment of passive, natural- circulation-driven decay heat removal systems, using these validated models; evaluation of life cycle carbon dioxide emissions as a key environmental impact metric; and recommendations for further work to apply these frameworks in the development and optimization of advanced nuclear reactor designs. In this study, the developed frameworks are applied to the analysis of the Mark 1 pebble-bed FHR (Mk1 PB-FHR) under current investigation at the University of California, Berkeley (UCB). The capability to validate integral transient response models is a key issue for licensing new reactor designs. This dissertation presents the scaling strategy, design and fabrication aspects, and startup testing results from the Compact Integral Effects Test (CIET) facility at UCB, which reproduces the thermal hydraulic response of an FHR under forced and natural circulation operation. CIET provides validation data to confirm the performance of the direct reactor auxiliary cooling system (DRACS) in an FHR, used for natural-circulation-driven decay heat removal, under a set of reference licensing basis events, as predicted by best-estimate codes such as RELAP5-3D. CIET uses a simulant fluid, Dowtherm A oil, which at relatively low temperatures (50-120°C) matches the Prandtl, Reynolds, Froude and Grashof numbers of the major liquid salts simultaneously, at approximately 50% geometric scale and heater power under 2% of prototypical conditions. The studies reported here include isothermal pressure drop tests performed during startup testing of CIET, with extensive pressure data collection to determine friction losses in the system, as well as subsequent heated tests, from parasitic heat loss tests to more complex feedback control tests and natural circulation experiments. For initial code validation, coupled steady-state single-phase natural circulation loops and simple forced cooling transients were conducted in CIET. For various heat input levels and temperature boundary conditions, fluid mass flow rates and temperatures were compared between RELAP5- 3D results, analytical solutions when available, and experimental data. This study shows that RELAP5-3D provides excellent predictions of steady-state natural circulation and simple transient forced cooling in CIET. The code predicts natural circulation mass flow rates within 8%, and steady-state and transient fluid temperatures, under both natural and forced circulation, within 2°C of experimental data, suggesting that RELAP5-3D is a good EM to use to design and license FHRs. A key element in design and licensing of new reactor technology lies in the analysis of the plant response to a variety of potential transients. When applicable, this involves understanding of passive safety system behavior. This dissertation develops a framework to assess reliability and propose design optimization and risk mitigation strategies associated with passive decay heat removal systems, applied to the Mk1 PB-FHR DRACS. This investigation builds upon previous detailed design work for Mk1 components and the use of RELAP5-3D models validated for FHR natural circulation phenomenology. For risk assessment, reliability of the point design of the passive safety system for the Mk1 PB-FHR, which depends on the ability of various structures to fulfill their safety functions, is studied. Whereas traditional probabilistic risk assessment (PRA) methods are based on event and fault trees for components of the system that perform in a binary way - operating or not operating -, this study is mostly based on probability distributions of heat load compared to the capacity of the system to remove heat, as recommended by the reliability methods for passive safety functions (RMPS) that are used here. To reduce computational time, the use of response surfaces to describe the system in a simplified manner, in the context of RMPS, is also demonstrated. The design optimization and risk mitigation part proposes a framework to study the elements of the design of the reactor, and more specifically its passive safety cooling system, which can contribute to enhanced reliability of heat removal under accident conditions. Risk mitigation measures based on design, startup testing, in-service inspection and online monitoring are proposed to narrow probability distributions of key parameters of the system and increase reliability and safety. Another major aspect in the development of novel energy systems is the assessment of their impacts on the environment compared to current technologies. While most existing life cycle assessment (LCA) studies have been applied to conventional nuclear power plants, this dissertation proposes a framework to extend such studies to advanced reactor designs, using the example of the Mk1 PB-FHR. The Mk1 uses a nuclear air-Brayton combined cycle designed to produce 100 MWe of base-load electricity when operated with only nuclear heat, and 242 MWe using natural gas co-firing for peaking power. The Mk1 design provides a basis for quantities and costs of major classes of materials involved in building the reactor and fabricating fuel, and operation parameters. Existing data and economic input-output LCA models are used to calculate greenhouse gas emissions per kWh of electricity produced over the life cycle of the reactor. Baseline life cycle emissions from the Mk1 PB-FHR in base-load configuration are 26% lower than average Generation II light water reactors in the U.S., 98% lower than average U.S. coal plants and 96% lower than average U.S. natural gas combined cycle plants using the same turbine technology. In peaking configuration, due to its nuclear component and higher thermal efficiency, the Mk1 plant only produces 32% of the emissions of average U.S. gas turbine simple cycle peaking plants. One key contribution to life cycle emissions results from the amount and type of concrete used for reactor construction. This is an incentive to develop innovative construction methods using optimized steel-concrete composite wall modules and new concrete mixes to reduce life cycle emissions from the Mk1 and other advanced reactor designs.

Download or read book Final Report passive Safety Optimization in Liquid Sodium cooled Reactors written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This report summarizes the results of a three-year collaboration between Argonne National Laboratory (ANL) and the Korea Atomic Energy Research Institute (KAERI) to identify and quantify the performance of innovative design features in metallic-fueled, sodium-cooled fast reactor designs. The objective of the work was to establish the reliability and safety margin enhancements provided by design innovations offering significant potential for construction, maintenance, and operating cost reductions. The project goal was accomplished with a combination of advanced model development (Task 1), analysis of innovative design and safety features (Tasks 2 and 3), and planning of key safety experiments (Task 4). Task 1--Computational Methods for Analysis of Passive Safety Design Features: An advanced three-dimensional subassembly thermal-hydraulic model was developed jointly and implemented in ANL and KAERI computer codes. The objective of the model development effort was to provide a high-accuracy capability to predict fuel, cladding, coolant, and structural temperatures in reactor fuel subassemblies, and thereby reduce the uncertainties associated with lower fidelity models previously used for safety and design analysis. The project included model formulation, implementation, and verification by application to available reactor tests performed at EBR-II. Task 2--Comparative Analysis and Evaluation of Innovative Design Features: Integrated safety assessments of innovative liquid metal reactor designs were performed to quantify the performance of inherent safety features. The objective of the analysis effort was to identify the potential safety margin enhancements possible in a sodium-cooled, metal-fueled reactor design by use of passive safety mechanisms to mitigate low-probability accident consequences. The project included baseline analyses using state-of-the-art computational models and advanced analyses using the new model developed in Task 1. Task 3--Safety Implications of Advanced Technology Power Conversion and Design Innovations and Simplifications: Investigations of supercritical CO2 gas turbine Brayton cycles coupled to the sodium-cooled reactors and innovative concepts for sodium-to-CO2 heat exchangers were performed to discover new designs for high efficiency electricity production. The objective of the analyses was to characterize the design and safety performance of equipment needed to implement the new power cycle. The project included considerations of heat transfer and power conversion systems arrangements and evaluations of systems performance. Task 4--Post Accident Heat Removal and In-Vessel Retention: Test plans were developed to evaluate (1) freezing and plugging of molten metallic fuel in subassembly geometry, (2) retention of metallic fuel core melt debris within reactor vessel structures, and (3) consequences of intermixing of high pressure CO2 and sodium. The objective of the test plan development was to provide planning for measurements of data needed to characterize the consequences of very low probability accident sequences unique to metallic fuel and CO2 Brayton power cycles. The project produced three test plans ready for execution.

Download or read book Use of DRACS to Enhance HTGRs Passive Safety and Economy written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper discusses the use of DRACS to Enhance HTGRs Passive Safety and Economy. One of the important requirements for Gen. IV High Temperature Gas Cooled Reactors (HTGR) is passive safety. Currently all the HTGR designs use Reactor Vessel Auxiliary Cooling System (RVACS) for passive decay heat removal. [1] The decay heat first is transferred to core barrel by conduction and radiation, and then to reactor vessel by thermal radiation and convection; finally the decay heat is transferred to natural circulated air or water systems. RVACS can be characterized as a surface based decay heat removal system. Similar concepts have been widely used in sodium cooled fast reactor (SFR) designs, advanced light water reactors like AP1000. The RVACS is especially suitable for smaller power reactors since small systems have relatively larger surface area. RVACS tends to be less expensive. However, it limits the largest achievable power level for modular HTGRs due to the mismatch between the reactor power (proportional to volume) and decay heat removal capability (proportional to surface). When the relative decay heat removal capability is reduced, the peak fuel temperature increases, even close to the design limit. Annual designs with internal reflector can mitigate this effect therefore further increase the power. Another way to increase power is to increase power density. However, it is also limited by the decay heat removal capability. Besides safety, HTGRs also need to be economical in order to compete with other reactor designs. The limit of decay heat removal capability set by using RVACS has affected the economy of HTGRs. Forsberg [2] pointed out other disadvantages of using RVACS such as conflicting functional requirements for the reactor vessel and scaling distortion for integral effect test of the system performance. A potential alternative solution is to use a volume based passive decay removal system, call Direct Reactor Auxiliary Cooling Systems (DRACS), to remove or mitigate the limitation on decay heat removal capability. DRACS has been widely used in SFR designs and in liquid salt cooled high temperature reactors. The containment cooling system in BWR is another example of volume based decay removal systems. DRACS composes of natural circulation loops with two sets of heat exchangers, one in reactor side and another is in environment side. DRACS has the benefits of increasing the power as needed (scalability) and modularity. This paper introduces the concept of using DRACS to enhance HTGRs passive safety and economy.

Download or read book Testing of Passive Safety System Performance for Higher Power Advanced Reactors written by Richard Wright and published by . This book was released on 2004 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes the results of NERI research on the testing of advanced passive safety performance for the Westinghouse AP1000 design. The objectives of this research were: (a) to assess the AP1000 passive safety system core cooling performance under high decay power conditions for a spectrum of breaks located at a variety of locations, (b) to compare advanced thermal hydraulic computer code predictions to the APEX high decay power test data and (c) to develop new passive safety system concepts that could be used for Generation IV higher power reactors.

Download or read book Thermal Hydraulics of Water Cooled Nuclear Reactors written by Francesco D'Auria and published by Woodhead Publishing. This book was released on 2017-05-18 with total page 1198 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermal Hydraulics of Water-Cooled Nuclear Reactors reviews flow and heat transfer phenomena in nuclear systems and examines the critical contribution of this analysis to nuclear technology development. With a strong focus on system thermal hydraulics (SYS TH), the book provides a detailed, yet approachable, presentation of current approaches to reactor thermal hydraulic analysis, also considering the importance of this discipline for the design and operation of safe and efficient water-cooled and moderated reactors. Part One presents the background to nuclear thermal hydraulics, starting with a historical perspective, defining key terms, and considering thermal hydraulics requirements in nuclear technology. Part Two addresses the principles of thermodynamics and relevant target phenomena in nuclear systems. Next, the book focuses on nuclear thermal hydraulics modeling, covering the key areas of heat transfer and pressure drops, then moving on to an introduction to SYS TH and computational fluid dynamics codes. The final part of the book reviews the application of thermal hydraulics in nuclear technology, with chapters on V&V and uncertainty in SYS TH codes, the BEPU approach, and applications to new reactor design, plant lifetime extension, and accident analysis. This book is a valuable resource for academics, graduate students, and professionals studying the thermal hydraulic analysis of nuclear power plants and using SYS TH to demonstrate their safety and acceptability. Contains a systematic and comprehensive review of current approaches to the thermal-hydraulic analysis of water-cooled and moderated nuclear reactors Clearly presents the relationship between system level (top-down analysis) and component level phenomenology (bottom-up analysis) Provides a strong focus on nuclear system thermal hydraulic (SYS TH) codes Presents detailed coverage of the applications of thermal-hydraulics to demonstrate the safety and acceptability of nuclear power plants

Download or read book Status of Research and Technology Development for Supercritical Water Cooled Reactors written by International Atomic Energy Agency and published by International Atomic Energy Agency. This book was released on 2019-05-22 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is considerable interest in both developing and developed countries in the design of innovative water cooled reactors (WCRs) and, owing to the higher thermal efficiency and significant system simplifications, supercritical water cooled reactors (SWCRs). Compared to conventional WCRs the SCWR concept requires extensive, comprehensive research and development (R&D). Fundamental research in understanding important phenomena has been completed successfully in providing information required for the next step of development. Currently, a few concepts have been assessed as being technical feasible, and several other concepts are under development. These concepts are described in this publication, together with detailed analysis of remaining gaps requiring future R&D.

Download or read book Energy Electricity and Nuclear Power Estimates for the Period Up to 2020 written by International Atomic Energy Agency and published by . This book was released on 2000 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the twentieth edition of Reference Data Series No. 1, containing the most recent estimates of energy, electricity and nuclear power trends up to the year 2020. Nuclear data are based on actual statistical data collected by the IAEA's Power Reactor Information System (PRIS). Energy, electricity and population data for 1999 are estimates based on information from the Department of Economic and Social Affairs of the United Nations.