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Design And Analysis Of The Very High Temperature Gas Cooled Reactor Driven Nuclear Hydrogen Production System Based On Sulfur Iodine Thermochemical Cycle And Gas Steam Combined Cycle
Download Design And Analysis Of The Very High Temperature Gas Cooled Reactor Driven Nuclear Hydrogen Production System Based On Sulfur Iodine Thermochemical Cycle And Gas Steam Combined Cycle full books in PDF, epub, and Kindle. Read online Design And Analysis Of The Very High Temperature Gas Cooled Reactor Driven Nuclear Hydrogen Production System Based On Sulfur Iodine Thermochemical Cycle And Gas Steam Combined Cycle ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!
Book Synopsis Design and Analysis of the Very High Temperature Gas-cooled Reactor-driven Nuclear Hydrogen Production System Based on Sulfur-iodine Thermochemical Cycle and Gas-steam Combined Cycle by : Qi Wang
Download or read book Design and Analysis of the Very High Temperature Gas-cooled Reactor-driven Nuclear Hydrogen Production System Based on Sulfur-iodine Thermochemical Cycle and Gas-steam Combined Cycle written by Qi Wang and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Analysis of Reference Design for Nuclear-Assisted Hydrogen Production at 750°C Reactor Outlet Temperature by :
Download or read book Analysis of Reference Design for Nuclear-Assisted Hydrogen Production at 750°C Reactor Outlet Temperature written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of High Temperature Electrolysis (HTE) for the efficient production of hydrogen without the greenhouse gas emissions associated with conventional fossil-fuel hydrogen production techniques has been under investigation at the Idaho National Engineering Laboratory (INL) for the last several years. The activities at the INL have included the development, testing and analysis of large numbers of solid oxide electrolysis cells, and the analyses of potential plant designs for large scale production of hydrogen using a high-temperature gas-cooled reactor (HTGR) to provide the process heat and electricity to drive the electrolysis process. The results of this research led to the selection in 2009 of HTE as the preferred concept in the U.S. Department of Energy (DOE) hydrogen technology down-selection process. However, the down-selection process, along with continued technical assessments at the INL, has resulted in a number of proposed modifications and refinements to improve the original INL reference HTE design. These modifications include changes in plant configuration, operating conditions and individual component designs. This report describes the resulting new INL reference design coupled to two alternative HTGR power conversion systems, a Steam Rankine Cycle and a Combined Cycle (a Helium Brayton Cycle with a Steam Rankine Bottoming Cycle). Results of system analyses performed to optimize the design and to determine required plant performance and operating conditions when coupled to the two different power cycles are also presented. A 600 MWt high temperature gas reactor coupled with a Rankine steam power cycle at a thermal efficiency of 44.4% can produce 1.85 kg/s of hydrogen and 14.6 kg/s of oxygen. The same capacity reactor coupled with a combined cycle at a thermal efficiency of 42.5% can produce 1.78 kg/s of hydrogen and 14.0 kg/s of oxygen.
Book Synopsis Development of Design and Simulation Model and Safety Study of Large-scale Hydrogen Production Using Nuclear Power by :
Download or read book Development of Design and Simulation Model and Safety Study of Large-scale Hydrogen Production Using Nuclear Power written by and published by . This book was released on 2007 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: Before this LDRD research, no single tool could simulate a very high temperature reactor (VHTR) that is coupled to a secondary system and the sulfur iodine (SI) thermochemistry. Furthermore, the SI chemistry could only be modeled in steady state, typically via flow sheets. Additionally, the MELCOR nuclear reactor analysis code was suitable only for the modeling of light water reactors, not gas-cooled reactors. We extended MELCOR in order to address the above deficiencies. In particular, we developed three VHTR input models, added generalized, modular secondary system components, developed reactor point kinetics, included transient thermochemistry for the most important cycles [SI and the Westinghouse hybrid sulfur], and developed an interactive graphical user interface for full plant visualization. The new tool is called MELCOR-H2, and it allows users to maximize hydrogen and electrical production, as well as enhance overall plant safety. We conducted validation and verification studies on the key models, and showed that the MELCOR-H2 results typically compared to within less than 5% from experimental data, code-to-code comparisons, and/or analytical solutions.
Book Synopsis An Assessment of Reactor Types for Thermochemical Hydrogen Production by :
Download or read book An Assessment of Reactor Types for Thermochemical Hydrogen Production written by and published by . This book was released on 2002 with total page 53 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nuclear energy has been proposed as a heat source for producing hydrogen from water using a sulfur-iodine thermochemical cycle. This document presents an assessment of the suitability of various reactor types for this application. The basic requirement for the reactor is the delivery of 900 C heat to a process interface heat exchanger. Ideally, the reactor heat source should not in itself present any significant design, safety, operational, or economic issues. This study found that Pressurized and Boiling Water Reactors, Organic-Cooled Reactors, and Gas-Core Reactors were unsuitable for the intended application. Although Alkali Metal-Cooled and Liquid-Core Reactors are possible candidates, they present significant development risks for the required conditions. Heavy Metal-Cooled Reactors and Molten Salt-Cooled Reactors have the potential to meet requirements, however, the cost and time required for their development may be appreciable. Gas-Cooled Reactors (GCRs) have been successfully operated in the required 900 C coolant temperature range, and do not present any obvious design, safety, operational, or economic issues. Altogether, the GCRs approach appears to be very well suited as a heat source for the intended application, and no major development work is identified. This study recommends using the Gas-Cooled Reactor as the baseline reactor concept for a sulfur-iodine cycle for hydrogen generation.
Book Synopsis Review of DOE's Nuclear Energy Research and Development Program by : National Research Council
Download or read book Review of DOE's Nuclear Energy Research and Development Program written by National Research Council and published by National Academies Press. This book was released on 2008-05-01 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: There has been a substantial resurgence of interest in nuclear power in the United States over the past few years. One consequence has been a rapid growth in the research budget of DOE's Office of Nuclear Energy (NE). In light of this growth, the Office of Management and Budget included within the FY2006 budget request a study by the National Academy of Sciences to review the NE research programs and recommend priorities among those programs. The programs to be evaluated were: Nuclear Power 2010 (NP 2010), Generation IV (GEN IV), the Nuclear Hydrogen Initiative (NHI), the Global Nuclear Energy Partnership (GNEP)/Advanced Fuel Cycle Initiative (AFCI), and the Idaho National Laboratory (INL) facilities. This book presents a description and analysis of each program along with specific findings and recommendations. It also provides an assessment of program priorities and oversight.
Book Synopsis Advances in High Temperature Gas Cooled Reactor Fuel Technology by : International Atomic Energy Agency
Download or read book Advances in High Temperature Gas Cooled Reactor Fuel Technology written by International Atomic Energy Agency and published by . This book was released on 2012-06 with total page 639 pages. Available in PDF, EPUB and Kindle. Book excerpt: This publication reports on the results of a coordinated research project on advances in high temperature gas cooled reactor (HTGR) fuel technology and describes the findings of research activities on coated particle developments. These comprise two specific benchmark exercises with the application of HTGR fuel performance and fission product release codes, which helped compare the quality and validity of the computer models against experimental data. The project participants also examined techniques for fuel characterization and advanced quality assessment/quality control. The key exercise included a round-robin experimental study on the measurements of fuel kernel and particle coating properties of recent Korean, South African and US coated particle productions applying the respective qualification measures of each participating Member State. The summary report documents the results and conclusions achieved by the project and underlines the added value to contemporary knowledge on HTGR fuel.
Book Synopsis Design Configurations and Coupling High Temperature Gas-Cooled Reactor and Hydrogen Plant by :
Download or read book Design Configurations and Coupling High Temperature Gas-Cooled Reactor and Hydrogen Plant written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The US Department of Energy is investigating the use of high-temperature nuclear reactors to produce hydrogen using either thermochemical cycles or high-temperature electrolysis. Although the hydrogen production processes are in an early stage of development, coupling either of these processes to the high-temperature reactor requires both efficient heat transfer and adequate separation of the facilities to assure that off-normal events in the production facility do not impact the nuclear power plant. An intermediate heat transport loop will be required to separate the operations and safety functions of the nuclear and hydrogen plants. A next generation high-temperature reactor could be envisioned as a single-purpose facility that produces hydrogen or a dual-purpose facility that produces hydrogen and electricity. Early plants, such as the proposed Next Generation Nuclear Plant (NGNP), may be dual-purpose facilities that demonstrate both hydrogen and efficient electrical generation. Later plants could be single-purpose facilities. At this stage of development, both single- and dual-purpose facilities need to be understood.
Book Synopsis Hydrogen Production from Nuclear Energy by : Greg F Naterer
Download or read book Hydrogen Production from Nuclear Energy written by Greg F Naterer and published by Springer Science & Business Media. This book was released on 2013-03-28 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the resurgence of nuclear power around the world, and the increasingly important role of hydrogen as a clean energy carrier, the utilization of nuclear energy for large-scale hydrogen production will have a key role in a sustainable energy future. Co-generation of both electricity and hydrogen from nuclear plants will become increasingly attractive. It enables load leveling together with renewable energy and storage of electricity in the form of hydrogen, when electricity prices and demand are lowest at off-peak hours of nuclear plants, such as overnight. Hydrogen Production from Nuclear Energy provides an overview of the latest developments and methods of nuclear based hydrogen production, including electrolysis and thermochemical cycles. Particular focus is given to thermochemical water splitting by the copper-chlorine and sulphur-based cycles. Cycle configurations, equipment design, modeling and implementation issues are presented and discussed. The book provides the reader with an overview of the key enabling technologies towards the design and industrialization of hydrogen plants that are co-located and linked with nuclear plants in the future. The book includes illustrations of technology developments, tables that summarize key features and results, overviews of recent advances and new methods of nuclear hydrogen production. The latest results from leading authorities in the fields will be presented, including efficiencies, costs, equipment design, and modeling.
Book Synopsis Nuclear Hydrogen Production Handbook by : Xing L. Yan
Download or read book Nuclear Hydrogen Production Handbook written by Xing L. Yan and published by CRC Press. This book was released on 2016-04-19 with total page 939 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by two leading researchers from the world-renowned Japan Atomic Energy Agency, the Nuclear Hydrogen Production Handbook is an unrivalled overview of current and future prospects for the effective production of hydrogen via nuclear energy. Combining information from scholarly analyses, industrial data, references, and other resources, this h
Book Synopsis Analysis of a High Temperature Gas-Cooled Reactor Powered High Temperature Electrolysis Hydrogen Plant by :
Download or read book Analysis of a High Temperature Gas-Cooled Reactor Powered High Temperature Electrolysis Hydrogen Plant written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: An updated reference design for a commercial-scale high-temperature electrolysis (HTE) plant for hydrogen production has been developed. The HTE plant is powered by a high-temperature gas-cooled reactor (HTGR) whose configuration and operating conditions are based on the latest design parameters planned for the Next Generation Nuclear Plant (NGNP). The current HTGR reference design specifies a reactor power of 600 MWt, with a primary system pressure of 7.0 MPa, and reactor inlet and outlet fluid temperatures of 322°C and 750°C, respectively. The reactor heat is used to produce heat and electric power to the HTE plant. A Rankine steam cycle with a power conversion efficiency of 44.4% was used to provide the electric power. The electrolysis unit used to produce hydrogen includes 1.1 million cells with a per-cell active area of 225 cm2. The reference hydrogen production plant operates at a system pressure of 5.0 MPa, and utilizes a steam-sweep system to remove the excess oxygen that is evolved on the anode (oxygen) side of the electrolyzer. The overall system thermal-to-hydrogen production efficiency (based on the higher heating value of the produced hydrogen) is 42.8% at a hydrogen production rate of 1.85 kg/s (66 million SCFD) and an oxygen production rate of 14.6 kg/s (33 million SCFD). An economic analysis of this plant was performed with realistic financial and cost estimating The results of the economic analysis demonstrated that the HTE hydrogen production plant driven by a high-temperature helium-cooled nuclear power plant can deliver hydrogen at a competitive cost. A cost of $3.03/kg of hydrogen was calculated assuming an internal rate of return of 10% and a debt to equity ratio of 80%/20% for a reactor cost of $2000/kWt and $2.41/kg of hydrogen for a reactor cost of $1400/kWt.
Book Synopsis Development of the Hybrid Sulfur Thermochemical Cycle by : John L. Steimke
Download or read book Development of the Hybrid Sulfur Thermochemical Cycle written by John L. Steimke and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The production of hydrogen via the thermochemical splitting of water is being considered as a primary means for utilizing the heat from advanced nuclear reactors to provide fuel for a hydrogen economy. The Hybrid Sulfur (HyS) Process is one of the baseline candidates identified by the U.S. Department of Energy [1] for this purpose. The HyS Process is a two-step hybrid thermochemical cycle that only involves sulfur, oxygen and hydrogen compounds. Recent work has resulted in an improved process design with a calculated overall thermal efficiency (nuclear heat to hydrogen, higher heating value basis) approaching 50%. Economic analyses indicate that a nuclear hydrogen plant employing the HyS Process in conjunction with an advanced gas-cooled nuclear reactor system can produce hydrogen at competitive prices. Experimental work has begun on the sulfur dioxide depolarized electrolyzer, the major developmental component in the cycle. Proof-of-concept tests have established proton-exchange-membrane cells (a state-of-the-art technology) as a viable approach for conducting this reaction. This is expected to lead to more efficient and economical cell designs than were previously available. Considerable development and scale-up issues remain to be resolved, but the development of a viable commercial-scale HyS Process should be feasible in time to meet the commercialization schedule for Generation IV gas-cooled nuclear reactors.
Book Synopsis Conceptual Design, Analysis and Optimization of Nuclear-based Hydrogen Production Via Copper-chlorine Thermochemical Cycles by : Mehmet Fatih Orhan
Download or read book Conceptual Design, Analysis and Optimization of Nuclear-based Hydrogen Production Via Copper-chlorine Thermochemical Cycles written by Mehmet Fatih Orhan and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The world faces problems with depleting energy resources and the harmful impact of present energy consumption patterns on the environment, and consequently on the global climate and humanity. The concerns regarding global climate change are serious and have resulted in extensive research and developments on alternative, clean energy sources. While many of the available natural energy resources are limited due to their reliability, quality, quantity and density; nuclear energy has the potential to contribute a significant share of large scale energy supply without or little contributing to climate change. Hydrogen production via thermochemical water decomposition is one of the key potential processes for direct utilization of nuclear thermal energy. Thermochemical water splitting with a copper-chlorine (Cu-Cl) cycle is a promising process that could be linked with nuclear reactors to decompose water into its constituents, oxygen and hydrogen as a net result, through intermediate copper and chlorine compounds with a net input of water and heat. The process involves a series of closed-loop chemical reactions that does not contribute to any greenhouse gas emissions into the environment. Although some preliminary technical studies of the Cu-Cl cycle have been reported and some small lab scale experiments of individual reactions in the cycle have been carried out, there is still a need to link all the sub-steps of the cycle and build a pilot plant, to facilitate eventual commercialization. Such an experimental set up of overall cycle is lacking, especially to evaluate characteristics of the complete cycle such as energy, exergy and cost effectiveness. Simulation packages, such as Aspen Plus, are useful tools to provide the system designer or operator with design, optimization and operation information before building a pilot plant. In this thesis, process analysis is performed and simulation models are developed using the Aspen Plus simulation package, based on experimental work carried out at the University of Ontario Institute of Technology (UOIT), the Argonne National Laboratory (ANL), the Atomic Energy of Canada Limited (AECL) and other sources. The energy and mass balances, stream flows and properties, the heat exchanger duties and shaft work are calculated. Heat recovery options are assessed to improve thermal management and hence overall efficiency of the Cu-Cl cycle. An integrated heat exchange network is designed to use heat from the process streams efficiently and decrease the external heat demand. The efficiency of the process, based on three, four and five-step cycles, is examined in this thesis. The thermal efficiency of the five-step thermochemical process is calculated as 44%, of the four-step process is 43% and of the three-step process is 41%, based on the lower heating value of hydrogen. Sensitivity analyses are performed to study the effects of various operating parameters on the efficiency, yield, and cost. A parametric study is conducted, and possible efficiency improvements are discussed. The manner is investigated in which exergy-related parameters can be used to minimize the cost of a Cu-Cl thermochemical cycle for hydrogen production. The iterative optimization technique presented requires a minimum of available data and provides effective assistance in optimizing thermal systems, particularly in dealing with complex systems and/or cases where conventional optimization techniques cannot be applied. The principles of thermoeconomics, as embodied in the specific exergy cost (SPECO) and exergy-cost-energy-mass (EXCEM) methods, are used here to determine changes in the design parameters of the cycle that improve the cost effectiveness of the overall system. It is found that the cost rate of exergy destruction varies between $1 and $15 per kilogram of hydrogen produced; and the exergoeconomic factor between 0.5 and 0.02 as the cost of hydrogen rises from $2.8 to $20 per kg of hydrogen produced. The hydrogen cost is inversely related to the exergoeconomic factor, plant capacity and energy/exergy efficiencies. Based on the cycle's design parameters and conditions the hydrogen production cost is calculated as $3.8/kg hydrogen. Also, an integrated Cu-Cl cycle hydrogen production system, based on nuclear and renewable energy sources, is investigated. Nuclear and renewable energy sources are reviewed to determine the most appropriate option to couple with the Cu-Cl cycle. An environmental impact assessment is conducted and compared to the conventional methods using fossil fuels and other options. Some cost assessment studies of hydrogen production are presented for this integrated system. The results show that hydrogen production cost could drop down to as low as 2.8 $/kg. The results are expected to assist ongoing efforts to increase the economic viability of the Cu-Cl cycle, and to reduce product costs of potential commercial versions of this process.
Book Synopsis Thermal Hydraulic Analyses for Coupling High Temperature Gas-Cooled Reactor to Hydrogen Plant by : S. Sherman
Download or read book Thermal Hydraulic Analyses for Coupling High Temperature Gas-Cooled Reactor to Hydrogen Plant written by S. Sherman and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The US Department of Energy is investigating the use of high-temperature nuclear reactors to produce hydrogen using either thermochemical cycles or high-temperature electrolysis. Although the hydrogen production processes are in an early stage of development, coupling either of these processes to the high-temperature reactor requires both efficient heat transfer and adequate separation of the facilities to assure that off-normal events in the production facility do not impact the nuclear power plant. An intermediate heat transport loop will be required to separate the operations and safety functions of the nuclear and hydrogen plants. A next generation high-temperature reactor could be envisioned as a single-purpose facility that produces hydrogen or a dual-purpose facility that produces hydrogen and electricity. Early plants, such as the proposed Next Generation Nuclear Plant (NGNP), may be dual-purpose facilities that demonstrate both hydrogen and efficient electrical generation. Later plants could be single-purpose facilities. At this stage of development, both single- and dual-purpose facilities need to be understood. A number of possible configurations for a system that transfers heat between the nuclear reactor and the hydrogen and/or electrical generation plants were identified. These configurations included both direct and indirect cycles for the production of electricity. Both helium and liquid salts were considered as the working fluid in the intermediate heat transport loop. Methods were developed toperform thermal-hydraulic and cycle-efficiency evaluations of the different configurations and coolants. The thermal-hydraulic evaluations estimated the sizes of various components in the intermediate heat transport loop for the different configurations. The relative sizes of components provide a relative indication of the capital cost associated with the various configurations. Estimates of the overall cycle efficiency of the various configurations were also determined. The evaluations determined which configurations and coolants are the most promising from thermalhydraulic and efficiency points of view.
Book Synopsis Hydrogen Production Technologies by : Mehmet Sankir
Download or read book Hydrogen Production Technologies written by Mehmet Sankir and published by John Wiley & Sons. This book was released on 2017-03-20 with total page 653 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides a comprehensive practical review of the new technologies used to obtain hydrogen more efficiently via catalytic, electrochemical, bio- and photohydrogen production. Hydrogen has been gaining more attention in both transportation and stationary power applications. Fuel cell-powered cars are on the roads and the automotive industry is demanding feasible and efficient technologies to produce hydrogen. The principles and methods described herein lead to reasonable mitigation of the great majority of problems associated with hydrogen production technologies. The chapters in this book are written by distinguished authors who have extensive experience in their fields, and readers will have a chance to compare the fundamental production techniques and learn about the pros and cons of these technologies. The book is organized into three parts. Part I shows the catalytic and electrochemical principles involved in hydrogen production technologies. Part II addresses hydrogen production from electrochemically active bacteria (EAB) by decomposing organic compound into hydrogen in microbial electrolysis cells (MECs). The final part of the book is concerned with photohydrogen generation. Recent developments in the area of semiconductor-based nanomaterials, specifically semiconductor oxides, nitrides and metal free semiconductor-based nanomaterials for photocatalytic hydrogen production are extensively discussed.
Author :General Dynamics Corporation. General Atomic Division. John Jay Hopkins Laboratory for Pure and Applied Science Publisher : ISBN 13 : Total Pages :246 pages Book Rating :4.3/5 (243 download)
Book Synopsis Design Study Report for TARGET by : General Dynamics Corporation. General Atomic Division. John Jay Hopkins Laboratory for Pure and Applied Science
Download or read book Design Study Report for TARGET written by General Dynamics Corporation. General Atomic Division. John Jay Hopkins Laboratory for Pure and Applied Science and published by . This book was released on 1964 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Hydrogen Supply Chain by : Catherine Azzaro-Pantel
Download or read book Hydrogen Supply Chain written by Catherine Azzaro-Pantel and published by Academic Press. This book was released on 2018-08-18 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt: Design, Deployment and Operation of a Hydrogen Supply Chain introduces current energy system and the challenges that may hinder the large-scale adoption of hydrogen as an energy carrier. It covers the different aspects of a methodological framework for designing a HSC, including production, storage, transportation and infrastructure. Each technology’s advantages and drawbacks are evaluated, including their technology readiness level (TRL). The multiple applications of hydrogen for energy are presented, including use in fuel cells, combustion engines, as an alternative to natural gas and power to gas. Through analysis and forecasting, the authors explore deployment scenarios, considering the dynamic aspect of HSCs. In addition, the book proposes methods and tools that can be selected for a multi-criteria optimal design, including performance drivers and economic, environmental and societal metrics. Due to its systems-based approach, this book is ideal for engineering professionals, researchers and graduate students in the field of energy systems, energy supply and management, process systems and even policymakers. Explores the key drivers of hydrogen supply chain design and performance evaluation, including production and storage facilities, transportation, information, sourcing, pricing and sustainability Presents multi-criteria tools for the optimization of hydrogen supply chains and their integration in the overall energy system Examines the available technology, their strengths and weaknesses, and their technology readiness levels (TRL), to draw future perspectives of hydrogen markets and propose deployment scenarios Includes international case studies of hydrogen supply chains at various scales
Book Synopsis Design Modification for the Modular Helium Reactor for Higher Temperature Operation and Reliability Studies for Nuclear Hydrogen Production Processes by : S. M. Mohsin Reza
Download or read book Design Modification for the Modular Helium Reactor for Higher Temperature Operation and Reliability Studies for Nuclear Hydrogen Production Processes written by S. M. Mohsin Reza and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Design options have been evaluated for the Modular Helium Reactor (MHR) for higher temperature operation. An alternative configuration for the MHR coolant inlet flow path is developed to reduce the peak vessel temperature (PVT). The coolant inlet path is shifted from the annular path between reactor core barrel and vessel wall through the permanent side reflector (PSR). The number and dimensions of coolant holes are varied to optimize the pressure drop, the inlet velocity, and the percentage of graphite removed from the PSR to create this inlet path. With the removal of ~10% of the graphite from PSR the PVT is reduced from 541 0C to 421 0C. A new design for the graphite block core has been evaluated and optimized to reduce the inlet coolant temperature with the aim of further reduction of PVT. The dimensions and number of fuel rods and coolant holes, and the triangular pitch have been changed and optimized. Different packing fractions for the new core design have been used to conserve the number of fuel particles. Thermal properties for the fuel elements are calculated and incorporated into these analyses. The inlet temperature, mass flow and bypass flow are optimized to limit the peak fuel temperature (PFT) within an acceptable range. Using both of these modifications together, the PVT is reduced to ~350 0C while keeping the outlet temperature at 950 0C and maintaining the PFT within acceptable limits. The vessel and fuel temperatures during low pressure conduction cooldown and high pressure conduction cooldown transients are found to be well below the design limits. The reliability and availability studies for coupled nuclear hydrogen production processes based on the sulfur iodine thermochemical process and high temperature electrolysis process have been accomplished. The fault tree models for both these processes are developed. Using information obtained on system configuration, component failure probability, component repair time and system operating modes and conditions, the system reliability and availability are assessed. Required redundancies are made to improve system reliability and to optimize the plant design for economic performance. The failure rates and outage factors of both processes are found to be well below the maximum acceptable range.
