Nuclear Science

Nuclear Energy Agency

ISSN :
1990-0643 (online)
ISSN :
1990-0651 (print)
DOI :
10.1787/19900643
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A series of publications from the OECD Nuclear Energy Agency on various aspects of nuclear science. The publications in this series (analytical reports and proceedings) provide research results and technical expertise in basic disciplines such as nuclear and radiation physics, thermal hydraulics, neutronics, fuel chemistry and material science which are needed to maintain a high level of performance and safety and to develop nuclear programmes.

 
Nuclear Production of Hydrogen

Nuclear Production of Hydrogen

Fourth Information Exchange Meeting, Oakbrook, Illinois, USA , 14-16 April 2009 You do not have access to this content

Nuclear Energy Agency

Authors:
OECD
Publication Date :
23 June 2010
Pages :
468
ISBN :
9789264087156 (PDF) ; 9789264087132 (print)
DOI :
10.1787/9789264087156-en

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Hydrogen has the potential to play an important role as a sustainable and environmentally acceptable energy carrier in the 21st century. This report describes the scientific and technical challenges associated with the production of hydrogen using heat and/or electricity from nuclear power plants, with special emphasis on recent developments in high-temperature electrolysis and the use of different chemical thermodynamic processes. Economics and market analysis as well as safety aspects of the nuclear production of hydrogen are also discussed.
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Expand / Collapse Hide / Show all Abstracts Table of Contents

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  • Foreword
    The use of hydrogen, both as feedstock for the industry (oil and chemical) and as an energy carrier, is expected to grow substantially during the coming decades. The current predominant method of producing hydrogen by steam-reforming methane (from natural gas) is not sustainable and has environmental drawbacks, including the emission of greenhouse gasses (GHGs). Nuclear energy offers a way to produce hydrogen from water without depleting natural gas, a valuable natural resource, and without the emission of GHGs.
  • Executive summary
  • Changing the world with hydrogen and nuclear
    I wish first to thank the organisers of this meeting who took the risk of inviting me to deliver this speech. I hope you have appetite for hydrogen and nuclear as by chance this is the subject of my talk. I took a great pleasure in reviewing the past history of hydrogen and nuclear energy, while considering how they had been important forever, how they have been used to change the world when they were discovered and understood, and how they will likely shape our future to face specific challenges of the 21st century. I hope I can make you share this interest and pleasure.
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  • Expand / Collapse Hide / Show all Abstracts Programme overview

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    • Nuclear hydrogen production programme in the United States
      The Nuclear Hydrogen Initiative (NHI) is focused on demonstrating the economic, commercial-scale production of hydrogen using process heat derived from nuclear energy. NHI-supported research has concentrated to date on three technologies compatible with the Next Generation Nuclear Plant (NGNP): high temperature steam electrolysis (HTE); sulphur-iodine (S-I) thermochemical; and hybrid sulphur (HyS) thermochemical. In 2009 NHI will down select to a single technology on which to focus its future development efforts, for which the next step will be a pilot-scale experiment.
    • French research strategy to use nuclear reactors for hydrogen production

      The demand for hydrogen, driven by classical applications such as fertilisers or oil refining as well as new applications (synthetic fuels, fuel cells,…) is growing significantly. Presently, most of the hydrogen produced in the world uses methane or another fossil feedstock, which is not a sustainable option, given the limited fossil resources and need to reduce CO2 emissions. This stimulates the need to develop alternative processes of production which do not suffer from these drawbacks.

    • Present status of HTGR and hydrogen production development in JAEA
      The high temperature gas-cooled reactor (HTGR), which is graphite-moderated and helium-cooled, is particularly attractive due to its unique capability of producing high temperature helium gas in addition to its fully inherent and passive safety characteristics. The HTGR-based production of hydrogen, the energy carrier for an emerging hydrogen economy, is expected to be among the most promising applications to solve the current environmental issues of CO2 emission. With this understanding the development studies of HTGR cogeneration system including hydrogen production have been carried out in Japan. This paper presents the 2100 vision of JAEA on future perspective of energy supply, especially on HTGR utilisation in the field of iron manufacturing, chemical industries, oil refineries, etc. In addition, this paper presents the present status of the HTTR Project including research and development activities of HTGR reactor technology, hydrogen production technology with the thermochemical water-splitting IS process, and the commercial HTGR plant design.
    • Status of the Korean nuclear hydrogen production project
      The rapid climate changes and the heavy reliance on imported fuel in Korea have motivated interest in the hydrogen economy. The Korean government has set up a long-term vision for transition to the hydrogen economy. To meet the expected demand of hydrogen as a fuel, hydrogen production using nuclear energy was also discussed. Recently the Korean Atomic Energy Committee has approved nuclear hydrogen production development and demonstration which will lead to commercialisation in late 2030s. An extensive research and development programme for the production of hydrogen using nuclear power has been underway since 2004 in Korea. During the first three years, a technological area was identified for the economic and efficient production of hydrogen using a VHTR.
    • The concept of nuclear hydrogen production based on MHR-T reactor
      The concept focused on nuclear power for steam reforming of methane and, later, on hydrogen production from water by high temperature solid oxide electrolysis. The programme arises from the premise that the use of hydrogen could grow world wide by a factor of about sixteen over the next century. Anticipating that the main source of hydrogen will continue to be steam reforming of natural gas during much of that period, by 2025, about a quarter of the world’s production of natural gas would be devoted to hydrogen generation, considering both its use as both the energy source and the source of the raw material. The use of nuclear reactors instead of natural gas as the heat source for steam reforming of methane could reduce the total use of natural gas by almost half.
    • Canadian nuclear hydrogen R&D programme
      Canada is developing the heavy-water-moderated supercritical water reactor as its Generation IV nuclear system. The medium temperature copper-chlorine (Cu-Cl) cycle has been selected as a suitable process for integration with this reactor system for large-scale production of hydrogen. A collaborative programme uniting the University of Ontario Institute of Technology (UOIT), Argonne National Laboratory (ANL) and Atomic Energy of Canada Limited (AECL) is underway for the development of the complete cycle for pilot plant demonstration. Canada’s Generation IV National Programme also supports the international efforts on VHTR through R&D on areas that are synergistic with the Canadian efforts on SCWR. Some of the latest results in the development of the Cu-Cl cycle and Canada’s contributions to the sulphur-iodine cycle are described in this paper.
    • Application of nuclear-produced hydrogen for energy and industrial use
      Hydrogen can be produced from water by thermochemical processes using nuclear heat or by electrochemical processes using nuclear electricity, or by "hybrid" processes combining both processes. As these nuclear water-splitting processes make it possible to produce hydrogen without any carbon dioxide emissions, they are mainstream methods to supply hydrogen as an energy carrier or as a feed material for industrial processes.
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  • Expand / Collapse Hide / Show all Abstracts High-temperature electrolysis

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    • Status of the INL high-temperature electrolysis research programme – experimental and modelling
      This paper provides a status update on the high-temperature electrolysis (HTE) research and development programme at Idaho National Laboratory (INL), with an overview of recent large-scale system modelling results and the status of the experimental programme. System analysis results have been obtained using the commercial code UniSim, augmented with a custom high-temperature electrolyser module. The process flow diagrams for the system simulations include an advanced nuclear reactor as a source of high-temperature process heat, a power cycle and a coupled steam electrolysis loop. Several reactor types and power cycles have been considered, over a range of reactor coolant outlet temperatures.
    • High-temperature steam electrolysis for hydrogen production
      High-temperature steam electrolysis (HTSE) coupled with nuclear energy is one of the most promising options for hydrogen mass production. CEA (the French Atomic Energy Commission) is carrying out research in this field, from materials, cells and components developments to stack design including components and stack testing.
    • Materials development for SOEC
      Emphasis on energy security issues has brought much-needed attention to economic production of hydrogen as the secondary energy carrier for non-electrical markets as well as to meet increasing demand for crude upgrading and desulphurisation. While steam reforming of methane is the current method of production of hydrogen, the fossil fuel feed consumes non-renewable fuel while emitting greenhouse gases. Thus, in the long run, efficient, environmentally-friendly and economic means of hydrogen production using nuclear and renewable energy needs to be developed. Steam electrolysis, particularly using high temperature ceramic membrane processes, provides an attractive option for efficient generation of high purity hydrogen.
    • A metallic seal for high-temperature electrolysis stacks
      Gas tightness over a long period of time is a real challenge in high-temperature electrolysis. The seals must indeed be able to run at high temperature between metals and brittle ceramic materials, which is a major issue to be solved. The common sealing solution relies on glass-made seals, despite their low mechanical strength at high temperature. Metallic seals have seldom been used in this field, because their stiffness and their hardness require a much higher load to achieve the appropriate tightness.
    • Degradation mechanisms in solid oxide electrolysis anodes
      High temperature steam electrolysis is one of the most efficient processes for hydrogen generation from water with no CO2 emissions using electricity and heat from nuclear or concentrated solar plants. Solid Oxide Electrolytic Cells (SOEC) are the proposed technology being researched and developed for this purpose. Over a long period of operation of the cells, various sources for degradation in the cells’ electrochemical performance prevail, and hence the cell resistance increases and the process becomes inefficient. Our research is aimed at identifying the mechanisms for the loss in the electrochemical performance of the cell, particularly of the oxygen electrode, namely the anode.
    • Causes of degradation in a solid oxide electrolysis stack
      Steam electrolysis experiments conducted at Idaho National Laboratory (INL) have demonstrated an efficient process to generate hydrogen using waste heat and electricity from a nuclear power plant. However, the hydrogen output was observed to decrease significantly over time. Solid oxide stack components from the INL studies were analysed at Argonne National Laboratory to elucidate the degradation mechanisms of electrolysis. After probable regions of degradation were identified by surface techniques, Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) were used to further characterise the causes of degradation by examining cross-sections of stack components.
    • Nuclear hydrogen using high temperature electrolysis and light water reactors for peak electricity production
      In a carbon-dioxide-constrained world, the primary methods to produce electricity (nuclear, solar, wind and fossil fuels with carbon sequestration) have low operating costs and high capital costs. To minimise the cost of electricity, these plants must operate at maximum capacity; however, the electrical outputs do not match changing electricity demands with time. A system to produce intermediate and peak electricity is described that uses light water reactors (LWR) and high temperature electrolysis. At times of low electricity demand the LWR provides steam and electricity to a high temperature steam electrolysis system to produce hydrogen and oxygen that are stored. At times of high electricity demand, the reactor produces electricity for the electrical grid. Additional peak electricity is produced by combining the hydrogen and oxygen by operating the high temperature electrolysis units in reverse as fuel cells or using an oxy-hydrogen steam cycle. The storage and use of hydrogen and oxygen for intermediate and peak power production reduces the capital cost, increases the efficiency of the peak power production systems, and enables nuclear energy to be used to meet daily, weekly and seasonal changes in electrical demand. The economic viability is based on the higher electricity prices paid for peak-load electricity.
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  • Expand / Collapse Hide / Show all Abstracts Thermochemical sulphur process

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    • CEA assessment of the sulphur-iodine cycle for hydrogen production

      The sulphur-iodine cycle is a promising process for hydrogen production using nuclear heat:

      • it is a purely thermochemical cycle, implying that hydrogen production will scale with volume rather than surface;
      • it only involves fluids, thus avoiding the often difficult handling of solids;
      • its heat requirements are well matched to the temperatures available from a Generation IV very/high temperature reactor.

    • Status of the INERI sulphur-iodine integrated-loop experiment
      In an International Nuclear Energy Research Initiative (INERI) project supported by the US DOE Office of Nuclear Energy, Sandia National Labs (SNL) has teamed with the Commissariat à l'Énergie Atomique (CEA) in France, and industrial partner General Atomics (GA) to construct and operate a closed-loop device for demonstration of hydrogen production by the S-I process. The Integrated Lab Scale (ILS) experiment is being conducted at General Atomics’ San Diego facility. This presentation will summarise project goals, work done to date, current status and scheduled future work on the INERI S-I integrated-loop experiment.
    • Influence of HTR core inlet and outlet temperatures on hydrogen generation efficiency using the sulphur-iodine water-splitting cycle
      Hydrogen generation is considered a promising application for VHTR. Simple thermodynamics show that the high temperature heat they can provide can lead to significant increase in efficiency when compared to low temperature processes, such as alkaline electrolysis coupled to a pressurised or boiling water reactor.
    • Experimental study of the vapour-liquid equilibria of HI-I2-H2O ternary mixtures
      In the framework of the massive production of hydrogen using the sulphur-iodine thermochemical cycle, the design of the reactive distillation column, chosen by CEA for the HIx section, requires the knowledge of the partial pressures of the gaseous species (HI, I2, H2O) in thermodynamic equilibrium with the liquid phase of the HI-I2-H2O ternary mixture in a wide range of concentrations up to 270°C and 50 bar. The experimental devices which enable the measurement of the total pressure and concentrations of the vapour phase (and thus the knowledge of the partial pressures of the different gaseous species) for the HI-I2-H2O mixture in the 20-250°C range and up to 35 bar are described.
    • Predicting the energy efficiency of a recuperative bayonet decomposition reactor for sulphur-based thermochemical hydrogen production
      High-temperature decomposition of sulphuric acid is a major step for sulphur-based thermochemical cycles such as hybrid sulphur and sulphur-iodine. It is generally also the most energy-intensive, so that the overall heat requirement for this step can determine whether a particular decomposition reactor or flow sheet design is practical.
    • Development of HI decomposition process in Korea
      The efficiency of producing hydrogen through a sulphur-iodine process is very sensitive to the HI decomposition process. In Korea, an electrodialysis method was selected to concentrate HI in the solution. The current status of HI concentration and decomposition characteristics with electrodialysis, distillation and HI decomposition catalyst is presented. Another sensitive item of iodine content is also briefly described. A future plan on how to demonstrate a lab-scale SI closed loop is also presented with key issues.
    • South Africa's nuclear hydrogen production development programme
      In May 2007 the South African Cabinet approved a National Hydrogen and Fuel Cell Technologies R&D and Innovation Strategy. The strategy will focus on research, development and innovation for: i) wealth creation through high value-added manufacturing and developing platinum group metals catalysis; ii) building on the existing knowledge in high temperature gas-cooled reactors (HTGR) and coal gasification Fischer-Tropsch technology, to develop local cost-competitive hydrogen production solutions; iii) to promote equity and inclusion in the economic benefits from South Africa’s natural resource base.
    • Integrated laboratory scale demonstration experiment of the hybrid sulphur cycle and preliminary scale-up
      The hybrid sulphur cycle is today one of the most promising processes to produce hydrogen on a massive scale within the scope of high temperature nuclear reactors development. Thus, the Fuel Cycle Technology Department at CEA Marcoule is involved in studying the hybrid sulphur process from a technical and economical performance standpoint. Based on mass and energy balance calculations, a ProsimPlusTM flow sheet and a commercial plant design were prepared. This work includes a study on sizing of the main equipment. The capital cost has been estimated using the major characteristics of main equipment based upon formulae and charts published in literature. A specific approach has been developed for electrolysers. Operational costs are also proposed for a plant producing 1 000 mol/s H2.
    • Development status of the hybrid sulphur thermochemical hydrogen production process
      The DOE Nuclear Hydrogen Initiative has selected two sulphur cycles, the sulphur iodine (SI) cycle and the HyS process, as the first priority thermochemical processes for development and potential demonstration with the next generation nuclear plant. Both cycles share a common high temperature reaction step – the catalytic thermal decomposition of sulphuric acid. However, they are fundamentally different in the methods used for the hydrogen production step.
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  • Expand / Collapse Hide / Show all Abstracts Thermochemical copper chloride and calcium bromide processes

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    • Recent Canadian advances in the thermochemical Cu-Cl cycle for nuclear hydrogen production
      This paper presents recent Canadian advances in nuclear-based production of hydrogen with the thermochemical copper-chlorine (Cu-Cl) cycle. Current collaboration between UOIT, Atomic Energy of Canada Limited, Argonne National Laboratory and partner institutions is focusing on enabling technologies for the Cu-Cl cycle, through the Generation IV International Forum. This paper presents the recent advances in the development of individual reactor designs, thermal efficiency, process developments, corrosion resistant materials and linkage between nuclear and hydrogen plants. The paper provides an overview of latest advances by a Canadian consortium that is collaborating on equipment scale-up for the Cu-Cl cycle.
    • An overview of R&D activities for the Cu-Cl cycle with emphasis on the hydrolysis reaction
      This paper describes the status of the development effort for the Cu-Cl thermochemical cycle. Most of the recent work has been focused on the hydrolysis reaction, which is challenging because of the need for excess steam to achieve high yields. Two types of spray reactors were tested and the ultrasonic nozzle gave excellent results. The conceptual process design for the overall process now includes a spray reactor. Engineering methods to increase efficiency are proposed. Preliminary values for the efficiency and capital costs for producing hydrogen using the Cu-Cl cycle have been calculated.
    • Study of the hydrolysis reaction of the copper-chloride hybrid thermochemical cycle using optical spectrometries
      The copper-chloride hybrid thermochemical cycle is one of the best potential low temperature thermochemical cycles for the massive production of hydrogen. It could be used with nuclear reactors such as the sodium fast reactor or the supercritical water reactor. Nevertheless, this thermochemical cycle is composed of an electrochemical reaction and two thermal reactions. Its efficiency has to be compared with other hydrogen production processes like alkaline electrolysis for example.
    • Development of CuCl-HCl electrolysis for hydrogen production via Cu-Cl thermochemical cycle
      The Cu-Cl thermochemical cycle is among the most attractive technologies proposed for hydrogen production due to moderate temperature requirements and high efficiency. In the present study, one of the main steps of the cycle – H2 gas production via CuCl-HCl electrolysis – was investigated using a newly designed electrolyser system. The electrolysis reaction was performed with the applied voltage from 0.35 to 0.9 V. The current efficiency of the electrolysis system was evaluated based on the observed rate of hydrogen production. The effects of temperature and reagent flow rate on the electrolysis performance were studied. Several types of anion-exchange and cation-exchange membranes were tested in the electrolyser, and their performance was compared with respect to process efficiency and tolerance to copper crossover.
    • Exergy analysis of the Cu-Cl cycle
      The CuCl cycle is a hybrid thermochemical cycle to produce hydrogen using both electricity and heat to split water into hydrogen and oxygen. Already described in the early 70s, it has recently been revisited because of its low maximal temperature and its high potential efficiency. Furthermore, raw materials are cheap, which allows a drastic diminution of constraints for industrial deployment.
    • CaBr2 hydrolysis for HBr production using a direct sparging contactor
      We investigated a novel, continuous hybrid cycle for hydrogen production employing both heat and electricity. Calcium bromide (CaBr2) hydrolysis, which is endothermic, generates hydrogen bromide (HBr), and this is electrolysed to produce hydrogen. CaBr2 hydrolysis at 1 050 K is endothermic with a 181.5 KJ/mol heat of reaction and the free energy change is positive at 99.6 kJ/mol. What makes this hydrolysis reaction attractive is both its rate and the fact that well over half the thermodynamic requirements for water-splitting free energy of ÄGT = 285.8 KJ/mol are supplied at this stage using heat rather than electricity.
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  • Expand / Collapse Hide / Show all Abstracts Economics and market analysis of hydrogen production and use

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    • The development of the Hydrogen Economic Evaluation Program (HEEP)
      The International Atomic Energy Agency (IAEA) is developing software to perform economic analysis related to hydrogen production. The software is expected to analyse the economics of the four most promising processes for hydrogen production. These processes are: high and low temperature electrolysis, thermochemical processes including the S-I process, conventional electrolysis and steam reforming.
    • Nuclear H2 production – a utility perspective
      Entergy is the second largest nuclear owner/operator in the United States with five nuclear units in the south operating under a cost of service structure and an additional six units in the Northeast and Midwest operating as merchant generating facilities. As a major nuclear operator in the merchant sector, Entergy wears the risk of nuclear operations – revenues are directly dependent upon operational performance. Our investment in merchant nuclear operations reflects our belief that use of nuclear energy in the competitive merchant environment can be an economically viable business venture.
    • Alkaline and high-temperature electrolysis for nuclear hydrogen production

      In anticipation to energy world evolution in the coming decades, we will discuss the role that hydrogen can play in the future energy systems.

      Facing strong energy demand growth in the transport field, expected oil production limitation and climate change constraints, the oil industry has to raise difficult challenges requiring short-term actions. Hydrogen being a key molecule for this industry, we will show how nuclear produced hydrogen can contribute to resolve some of the oil industry challenges, within a compatible time frame with the inertia of climate mechanisms.

    • The production of hydrogen by nuclear and solar heat
      Both nuclear and solar energy represent significant carbon-free sources, which may contribute robust elements to a cleaner energy economy, to develop domestic energy sources for the purpose of energy security and stability, and to reduce national dependencies on imports of fossil fuels. Hydrogen, on the other hand, represents a fuel which is clean, powerful and an environmentally benign source of energy to the end-user. The current production of hydrogen is mainly based on hydrocarbons as feedstock, e.g. steam reforming of natural gas.
    • Sustainable electricity supply in the world by 2050 for economic growth and automotive fuel
      Over the next 40 years, the combustion of fossil fuels for generation of electricity and vehicle transportation will be significantly reduced. In addition to the business-as-usual growth in electric energy demand for the growing world population, new electricity-intensive industries, such as battery electric vehicles and hydrogen fuel-cell vehicles will result in further growth in world consumption of electric energy. Planning for a sustainable supply of electric energy in the diverse economies of the world should be carried out with appropriate technology for selecting the appropriate large-scale energy resources based on their specific energy. Analysis of appropriate technology for the available large-scale energy resources with diminished use of fossil-fuel combustion shows that sustainable electricity supply can be achieved with equal contributions of renewable energy resources for large numbers of small-scale distributed applications and nuclear energy resources for the smaller number of large-scale centralised applications.
    • NHI economic analysis of candidate nuclear hydrogen processes
      The DOE Nuclear Hydrogen Initiative (NHI) is investigating candidate technologies for large scale hydrogen production using high temperature gas-cooled reactors (HTGR) in concert with the Next Generation Nuclear Plant (NGNP) programme. The candidate processes include high temperature thermochemical and high temperature electrolytic processes which are being investigated in a sequence of experimental and analytic studies to establish the most promising and cost effective means of hydrogen production with nuclear energy. Although these advanced processes are in an early development stage, it is important that the projected economic potential of these processes be evaluated to assist in the prioritisation of research activities, and ultimately in the selection of the most promising processes for demonstration and deployment.
    • Market viability of nuclear hydrogen technologies
      We analyse the market viability of four potential nuclear hydrogen technologies. We focus on the value of product flexibility, i.e. the value of the option to switch between hydrogen and electricity production depending on what is more profitable to sell. We find that flexibility in output product is likely to add significant economic value to a nuclear hydrogen plant. Electrochemical technologies lend themselves more easily to flexible production than thermochemical technologies. Potential investors in nuclear hydrogen may therefore see these as more viable in the marketplace.
    • Possibility of active carbon recycle energy system
      A new energy transformation system based on carbon recycle use was discussed. A concept of an Active Carbon Neutral Energy System (ACRES) was proposed. Carbon dioxide is regenerated artificially into hydrocarbons by using a heat source with non-carbon dioxide emission, and the regenerated hydrocarbon is re-used cyclically as an energy carrier media in ACRES. Feasibility of ACRES was examined thermodynamically in comparison with hydrogen energy system. Carbon monoxide was the most suitable for a recycle carbon media in ACRES because of relatively high energy density in comparison with hydrogen, and high acceptability to conventional chemical, steel and high-temperature manufacturing industries. A high-temperature gas reactor was a good power source for ACRES. ACRES with carbon monoxide as recycle media was expected to be one of the efficient energy utilisation systems for the reactor.
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  • Expand / Collapse Hide / Show all Abstracts Safety aspects of nuclear hydrogen production

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    • Nuclear safety and regulatory considerations for nuclear hydrogen production
      The use of a nuclear power plant to produce hydrogen or for other process heat applications will present challenges to the licensing process. Potential safety and regulatory issues have been evaluated to identify possible research needs, policy concerns and licensing approaches. A brief description of nuclear power plant licensing in the United States and a discussion of specific issues for using nuclear power plants for process heat applications are presented.
    • Transient modelling of sulphur-iodine cycle thermochemical hydrogen generation coupled to pebble bed modular reactor
      A transient control volume model of the sulphur iodine (S-I) and Westinghouse hybrid sulphur (HyS) cycles is presented. These cycles are some of the leading candidates for hydrogen generation using a high temperature heat source. The control volume models presented here are based on a heat and mass balance in each reaction chamber coupled to the relevant reaction kinetics. The chemical kinetics expressions are extracted from a relevant literature review.
    • Proposed chemical plant initiated accident scenarios in a sulphur-iodine cycle plant coupled to a pebble bed modular reactor
      In the sulphur-iodine (S-I) cycle nuclear hydrogen generation scheme the chemical plant acts as the heat sink for the very high temperature nuclear reactor (VHTR). Thus, any accident which occurs in the chemical plant must feedback to the nuclear reactor. There are many different types of accidents which can occur in a chemical plant. These accidents include intra-reactor piping failure, inter-reactor piping failure, reaction chamber failure and heat exchanger failure.
    • Conceptual design of the HTTR-IS nuclear hydrogen production system
      One of the key safety issues for nuclear hydrogen production is the heat transfer tube rupture in intermediated heat exchangers (IHX) which provide heat to process heat applications. This study focused on the detection method and system behaviour assessments during the IHX tube rupture scenario (IHXTR) in the HTTR coupled with IS process hydrogen production system (HTTR-IS system). The results indicate that monitoring the integral of secondary helium gas supply would be the most effective detection method. Furthermore, simultaneous actuation of two isolation valves could reduce the helium gas transportation from primary to secondary cooling systems. The results of system behaviour show that evaluation items do not exceed the acceptance criteria during the scenario. Maximum fuel temperature also does not exceed initial value and therefore the reactor core was not seriously damaged and cooled sufficiently.
    • Use of PSA for design of emergency mitigation systems in a hydrogen production plant using General Atomics SI cycle technology. Section II: Sulphuric acid decomposition
      Throughout the past decades, the need to reduce greenhouse gas emissions has prompted the development of technologies for the production of clean fuels through the use of zero emissions primary energy resources, such as heat from high temperature nuclear reactors. One of the most promising of these technologies is the generation of hydrogen by the sulphur-iodine cycle coupled to a high temperature nuclear reactor, initially proposed by General Atomics. By its nature and because these will have to be large-scale plants, development of these technologies from its current phase to its procurement and construction phase, will have to incorporate emergency mitigation systems in all its sections and nuclear-chemical "tie-in points" to prevent unwanted events that can compromise the integrity of the plant and the nearby population centres.
    • Heat pump cycle by hydrogen-absorbing alloys to assist high-temperature gas-cooled reactor in producing hydrogen
      A chemical heat pump system using two hydrogen-absorbing alloys is proposed to utilise heat exhausted from a high-temperature source such as a high-temperature gas-cooled reactor (HTGR), more efficiently. The heat pump system is designed to produce H2 based on the S-I cycle more efficiently. The overall system proposed here consists of HTGR, He gas turbines, chemical heat pumps and reaction vessels corresponding to the three-step decomposition reactions comprised in the S-I process. A fundamental research is experimentally performed on heat generation in a single bed packed with a hydrogen-absorbing alloy that may work at the H2 production temperature. The hydrogen-absorbing alloy of Zr(V1-XFeX)2 is selected as a material that has a proper plateau pressure for the heat pump system operated between the input and output temperatures of HTGR and reaction vessels of the S-I cycle. Temperature jump due to heat generated when the alloy absorbs H2 proves that the alloy–H2 system can heat up the exhaust gas even at 600°C without any external mechanical force.
    • Heat exchanger temperature response for duty-cycle transients in the NGNP/HTE
      Control system studies were performed for the next generation nuclear plant (NGNP) interfaced to the high-temperature electrolysis (HTE) plant. Temperature change and associated thermal stresses are important factors in determining plant lifetime. In the NGNP the design objective of a 40-year lifetime for the intermediate heat exchanger (IHX) in particular is seen as a challenge. A control system was designed to minimise temperature changes in the IHX and more generally at all high-temperature locations in the plant for duty-cycle transients. In the NGNP this includes structures at the reactor outlet and at the inlet to the turbine.
    • Alternate VHTR/HTE interface for mitigating tritium transport and structure creep
      High temperature creep in structures at the interface between the nuclear plant and the hydrogen plant and the migration of tritium from the core through structures in the interface are two key challenges for the very high temperature reactor (VHTR) coupled to the high temperature electrolysis (HTE) process. The severity of these challenges, however, can be reduced by lowering the temperature at which the interface operates. Preferably this should be accomplished in a way that does not reduce combined plant efficiency and other performance measures. A means for doing so is described. A heat pump is used to raise the temperature of near-waste heat from the PCU to the temperature at which nine-tenths of the HTE process heat is needed. In addition to mitigating tritium transport and creep of structures, structural material commodity costs are reduced and plant efficiency is increased by 1%.
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  • Expand / Collapse Hide / Show all Abstracts Poster session contributions

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    • Activities of Nuclear Research Institute Rez in the area of hydrogen technologies
      NRI is a research institution established in 1955. Nowadays, the Institute provides wide range of expertise and services for operators of the nuclear power plants in the Czech Republic and abroad, supports Czech central state institutions in the domains of strategic energy planning and development, management of radioactive waste (for the Ministry of Trade and Industry), provides independent expertise for the State Office of Nuclear Safety, performs activities in the area of exploitation of ionising radiation and irradiation services for basic and applied research, health service and industry, performs research and provides services for radioactive waste disposal, production of radiopharmaceuticals, education and training of experts and scientific specialists and performs many other activities.
    • A uranium thermochemical cycle for hydrogen production
      A modelling and experimental effort has identified a new uranium thermochemical cycle (UTC) for the production of hydrogen from water. The peak temperature within the cycle is below 700°C – a temperature achievable with existing high temperature nuclear reactors and some solar systems using commercially available materials. This paper describes the new process and some of the experimental work. It is an early report of chemical feasibility. Much work will be required to determine engineering and economic viability.
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