Synergistic hydrogen production by nuclear-heated steam reforming of fossil fuels

Processes and technologies to produce hydrogen synergistically by the nuclear-heated steam reforming reaction of fossil fuels are reviewed. Formulas of chemical reactions, required heats for reactions, saving of fuel consumption, reduction of carbon dioxide emission, and possible processes are investigated for such fossil fuels as natural gas, petroleum and coal.

In this investigation, examined are the steam reforming processes using the “membrane reformer” and adopting the recirculation of reaction products in a closed loop configuration. The recirculation-type membrane reformer process is considered to be the most advantageous among various synergistic hydrogen production processes. Typical merits of this process are; nuclear heat supply at medium temperature around 550°C, compact plant size and membrane area for hydrogen production, efficient conversion of a feed fossil fuel, appreciable reduction of carbon dioxide emission, high purity hydrogen without any additional process, and ease of separating carbon dioxide for future sequestration requirements.

The synergistic hydrogen production using fossil fuels and nuclear energy can be an effective solution in this century for the world which has to use fossil fuels to some extent, according to various estimates of global energy supply, while reducing carbon dioxide emission.     

Economic feasibility of heat supply from simple and safe nuclear plants

Use of nuclear energy as a heating source is greatly challenged by the economic factor since the nuclear heating reactors have relative small size and often the lower plant load factor. However, use of very simple reactor could be a possible way to economically supply heat. A deep pool reactor (DPR) has been designed for this purpose. The DPR is a novel design of pool type reactor for heat only supply. The reactor core is put in a deep pool. By only putting light static water pressure on the core coolant, the DPR will be able to meet the temperature requirements of heat supply for district heating. The feature of simplicity and safety of DPR makes a decrease of investment cost compared to other reactors for heating only purposes. According to the economical assessments, the capital investment to build a DPR plant is much less than that of a pressurized reactor with pressure vessels. For the DPR with 120 or 200 MW output, it can bear the economical comparison with a usual coal-fired heating plant. Some special means taken in DPR design make an increase of the burn-up level of spent fuel and a decrease of fuel cost. The feasibility studies of DPR in some cities in China show that heating cost using nuclear energy is only one third of that by coal and only one tenth of that by nature gas. Therefore, the DPR nuclear heating system provides an economically attractive solution to satisfy the demands of district heating without contributing to increasing greenhouse gas emissions.     

Simple and safe deep pool reactor for low-temperature heat supply

The deep pool reactor (DPR) is a novel design of pool type reactor for heat only supply. The reactor core is put in a deep pool and it is within the low working temperature range. By only putting light hydrostatic pressure on the core coolant, the DPR will be able to meet the temperature requirements of heat supply for district heating and seawater desalination.

This paper will cover its design characteristics and main conclusions of safety analyses and economic evaluation. The nuclear heating system provides a safe feasibility and economically attractive solution for supplying low-temperature heat and reducing greenhouse gas emissions.     

Nuclear energy option for energy security and sustainable development in India

India is facing great challenges in its economic development due to the impact on climate change. Energy is the important driver of economy. At present Indian energy sector is dominated by fossil fuel. Due to international pressure for green house gas reduction in atmosphere there is a need of clean energy supply for energy security and sustainable development. The nuclear energy is a sustainable solution in this context to overcome the environmental problem due to fossil fuel electricity generation. This paper examines the implications of penetration of nuclear energy in Indian power sector. Four scenarios, including base case scenario, have been developed using MARKAL energy modeling software for Indian power sector. The least-cost solution of energy mix has been measured. The result shows that more than 50% of the electricity market will be captured by nuclear energy in the year 2045. This ambitious goal can be expected to be achieved due to Indo-US nuclear deal. The advanced nuclear energy with conservation potential scenario shows that huge amounts of CO₂ can be reduced in the year 2045 with respect to the business as usual scenario.     

Nuclear energy for transportation: Paths through electricity, hydrogen and liquid fuels

The transportation sector consumes about a quarter of final energy in Japan and worldwide, and presently most of the energy is supplied by petroleum. For global environment and resources, it is important to seek possibilities of replacing a substantial part of the transportation energy by nuclear energy.

For supplying nuclear energy to the transportation sector, investigated are the paths through such ‘energy carriers’ as electricity, hydrogen and synthetic liquid fuels, to the means of transportation such as automobiles. These energy carriers can be produced from nuclear energy, by itself or synergistically with other primary energies like fossil fuels or biomass.

In this paper, possibilities and impacts of these energy carriers to power transportation means are reviewed, and measures and tasks to supply these energy carriers from nuclear energy are examined.

In converting the primary energies into the energy carriers, the synergistic process may be more advantageous than the individual process. Some of the exploratory processes to produce synthetic liquid fuels from fossil fuels and nuclear energy are presented.     

Nuclear central heating — prospects and solutions

Large-scale development of nuclear central heating — a radical expansion of a sphere of application, large increase of cost-effectiveness and self-financing of the construction of nuclear sources of energy, increase of their fraction in the base part of the load schedule, and large-scale displacement of fossil fuel — is validated. Suggestions for a program for developing nuclear heat and power plants are examined. It is shown that the power generating units of nuclear heat and power plants must satisfy specific requirements, which requires developing specialized reactor systems. The main technical and economic characteristics of an innovative simplified boiling water reactor VK-300, specially designed for central heating power generating units, the parameters of a central heating power generating unit with VK-300, and the results of validation of investments in the construction of the VK-300 nuclear heat and power plant in Arkhangel’sk are presented. __________ Translated from Atomnaya énergiya, Vol. 103, No. 1, pp. 36–40, July, 2007.     

Reactors for low-temperature nuclear heat supply

Nuclear sources are not only covering more than 16% of today's electricity production but can also supply heat for district heating and industrial needs. Thus the nuclear generated heat substitutes for fossil fuels with good efficiency and economy and with much higher environmental cleanliness. Low-temperature nuclear heat is gained in several countries from the reactors of nuclear power plants by co-generation of heat and electricity which is already a proven technology. Specialized nuclear heating plants are in an early stage of development. The paper gives an overview of the situation worldwide and shows also specific common safety characteristics of these reactors.     

The HTR and nuclear process heat applications

The High Temperature Reactor HTR offers beside the production of electricity the potential of the production of secondary energy carriers for the fuel and heat market. Therefore the HTR can considerably contribute to solutions of future problems in the energy supply of the Federal Republic of Germany as well as of the world. On the basis of the experiences with the power plants AVR, Fort St. Vrain and THTR-300 new concepts of reactors have been proposed: the medium size reactor HTR 500 and the Modular HTR concept. The high temperature heat application is directed towards the refinement of fossil fuels, the long distance energy system and other applications as e.g. process steam for chemical industry, enhanced oil recovery and water splitting. The research and development program in the projects Prototype Plant Nuclear Process Heat (PNP) and Nuclear Long Distance Energy (NFE) has shown very promising results. These results show that nuclear process heat is technically feasibly and that it is possible to reach a commercial application in the next decades.     

摩洛哥坦坦地区核能海水淡化示范项目

摩洛哥王国准备采用我国开发的１０ＭＷ核供热堆作为热源，与高温多效蒸馏工艺相耦合，在坦坦地区建造核能海水淡化示范厂，日产８０００ｍ＾３淡水，可行性研究结果表明：该示范厂设计方案不存在技术障碍，其淡水生产成本和该地区相同规模的石化燃料淡化厂相当。     

Physical characteristics and problems of developing a sodium-cooled fast reactor as a source of high-potential thermal energy for hydrogen production and other high-temperature technologies

Hydrogen as an energy carrier will play a considerable role in the future structure of energy production when nuclear reactors will replace fossil fuels. Investigations performed in recent years have shown that the production of large quantities of energy with high efficiency can be accomplished on the basis of thermochemical cycles using reactors with coolant temperature at the exit from the core of about 900°C. A variant of such a fast reactor with sodium as the coolant is proposed. The main physical characteristics and the main problems which must be solved to build such a reactor are presented. According to its properties, this reactor will meet the modern requirements for nuclear and radiation safety. It can also be used in other promising high-temperature technologies, for example, high-efficiency production of electricity. Deceased. (V. B. Bogush) Translated from Atomnaya énergiya, Vol. 106, No. 3, pp. 129–134, March, 2009.     

Coal gasification with heat from high temperature reactors: Objectives and status of the project “Prototype Plant for Nuclear Process Heat (PNP)”

It is by now fairly widely known that the high temperature reactor (HTR) is a unique nuclear energy source which can supply heat at temperatures up to 1000°C for application in chemical processes, for which previously exclusively combustion heat sources have been used. With the HTR, it is possible to apply nuclear energy not only for electrical power production but also for the synthesis of liquid or gaseous energy carriers. Nuclear coal gasification appears most promising as the first step for the demonstration and industrial application of nuclear process heat technology in the Federal Republic of Germany. Reactor manufacturers and coal mining companies in co-operation with the Nuclear Research Center at Jülich established a joint project in 1975 for the development of an HTR with a coolant outlet temperature of 950°C, for the development and testing of nuclear coal gasification, for the detailed engineering of a prototype plant consisting of an HTR and gasification plant and finally for the construction and operation of this prototype plant for nuclear process heat (PNP). This contribution describes the status of the PNP-Project and the scope for future development.     

Nuclear powered heat pumps for near-term process heat applications

There is a substantial market for nuclear energy in non-electric applications such as hydrogen production or water desalination. Among the Generation IV reactor concepts, the very high temperature reactor (VHTR) with a reactor outlet temperature close to 1000 °C and a power conversion efficiency of approximately 50% is believed to be the most suitable concept for co-generation of process heat. Its high coolant exergy would enable centralized hydrogen production and other process heat applications. In this paper it is shown that a reactor with lower coolant outlet temperature or another near-term heat source can also meet the VHTR objectives which are high power conversion efficiency and capability to deliver high temperature process heat in the narrow temperature window required by thermochemical hydrogen production cycles. The approach was to separate the requirement for high temperature process heat production from the nuclear part of the plant, in other words the nuclear part of the power plant would run at acceptably low temperature while the high temperature heat production via a heat pump system would be limited to a conventional external circuit, thus avoiding nuclear constraints. The separation of these high temperature constraints from the reactor would avoid massive R&D requirements on materials, components and fuel with uncertain outcome thus unnecessarily delaying introduction of this otherwise very attractive reactor concept.We then show that the proposed technology is equally suitable for the generation of cold (e.g. for air conditioning) and for desalination of seawater.     

Transport of nuclear heat by means of chemical energy (nuclear long-distance energy)

Nuclear long-distance energy, i.e. the transportation of chemically bound energy, represents a potential application for process heat plants in which the endothermic reaction takes place at the heat source (high temperature reactor) whereas the exothermic back reaction occurs at the region of heat utilization (consumer). Due to the following criteria, i.e. reversibility of the chemical reaction, sufficiently large reaction enthalpy, favourable temperature region for the forward and back reactions, and the available technology, a combination of the methods of endothermic steam reforming of methane and exothermic methanation is chosen. As well as supplying household and industrial consumers with heating, process steam and electrical energy, an interconnected system with synthesis gas consumers (e.g. methanol production and iron ore reduction plants) is possible. It is shown that the amount of reactor heat which is convertible into long-distance energy depends considerably on the helium temperatures in the high temperature reactor and lies between 60 and 73% of the reactor power. Conceivable circuit schemes for the nuclear steam-reforming plants and the methanation plants are described. Finally, it is demonstrated, with the help of a simple model for cost estimations, that the nuclear long-distance energy system can make heating for households available in competition with oil heating and that due to the lower specific transport costs, for distances larger than 50 km it is also more economical than the hot water supply from the thermal power coupling of steam turbine plants using light water reactors (LWRs) or high temperature reactors (HTRs).     

The swiss heating reactor (SHR) for district heating of small communities

With fossil fuel running out in a foreseeable future, it is essential to develop substitution strategies. Some 40–50% of the heat demand in industrial countries is below 120°C, for space heating and warm water production, causing a corresponding fraction of air polution by SO₂ and to a lesser extent NO_x if fossil fuels are used. Yet, contemporary LWR technology makes it feasible to supply a district heating network without basically new reactor development. Units in the power range 10–50 MW are most suitable for Switzerland, both in respect of network size and of the democratic decision making structure. A small BWR for heating purpose only is being developed by parts of the Swiss Industry and the Swiss Federal Institute for Reactor Research (EIR). The economic target of 100–120 SFr/MWh heat at the consumer's seems achievable.     

South Africa's opportunity to maximise the role of nuclear power in a global hydrogen economy

Global concern for increased energy demand, increased cost of natural gas and petroleum, energy security and environmental degradation are leading to heightened interest in using nuclear energy and hydrogen to leverage existing hydrocarbon reserves. The wasteful use of hydrocarbons can be minimised by using nuclear as a source of energy and water as a source of hydrogen. Virtually all hydrogen today is produced from fossil fuels, which give rise to CO₂ emissions. Hydrogen can be cleanly produced from water (without CO₂ pollution) by using nuclear energy to generate the required electricity and/or process heat to split the water molecule. Once the clean hydrogen has been produced, it can be used as feedstock to fuel cell technologies, or in the nearer term as feedstock to a coal-to-liquids process to produce cleaner synthetic liquid fuels. Clean liquid fuels from coal - using hydrogen generated from nuclear energy - is an intermediate step for using hydrogen to reduce pollution in the transport sector; simultaneously addressing energy security concerns. Several promising water-splitting technologies have been identified. Thermo-chemical water-splitting and high-temperature steam electrolysis technologies require process temperatures in the range of 850 °C and higher for the efficient production of hydrogen. The pebble bed modular reactor (PBMR), under development in South Africa, is ideally suited to generate both high-temperature process heat and electricity for the production of hydrogen. This paper will discuss South Africa's opportunity to maximise the use of its nuclear technology and national resources in a global hydrogen economy.     

Economic viability of small to medium-sized reactors deployed in future European energy markets

Future plans for energy production in the European Union as well as other locations call for a high penetration of renewable technologies (20% by 2020, and higher after 2020). The remaining energy requirements will be met by fossil fuels and nuclear energy. Smaller, less-capital intensive nuclear reactors are emerging as an alternative to fossil fuel and large nuclear systems. Approximately 50 small (<300 MWe) to medium-sized (<700 MWe) reactors (SMRs) concepts are being pursued for use in electricity and cogeneration (combined heat and power) markets. However, many of the SMRs are at the early design stage and full data needed for economic analysis or market assessment is not yet available. Therefore, the purpose of this study is to develop “target cost” estimates for reactors deployed in a range of competitive market situations (electricity prices ranging from 45-150 €/MWh). Parametric analysis was used to develop a cost breakdown for reactors that can compete against future natural gas and coal (with/without carbon capture) and large nuclear systems. Sensitivity analysis was performed to understand the impacts on competitiveness from key cost variables. This study suggests that SMRs may effectively compete in future electricity markets if their capital costs are controlled, favorable financing is obtained, and reactor capacity factors match those of current light water reactors. This methodology can be extended to cogeneration markets supporting a range of process heat applications.     

Evaluation of high temperature gas reactor for demanding cogeneration load follow

Modular nuclear reactor systems are being developed around the world for new missions among which is cogeneration for industries and remote areas. Like existing fossil energy counterpart in these markets, a nuclear plant would need to demonstrate the feasibility of load follow including (1) the reliability to generate power and heat simultaneously and alone and (2) the flexibility to vary cogeneration rates concurrent to demand changes. This article reports the results of JAEA's evaluation on the high temperature gas reactor (HTGR) to perform these duties. The evaluation results in a plant design based on the materials and design codes developed with JAEA's operating test reactor and from additional equipment validation programs. The 600 MWt-HTGR plant generates electricity efficiently by gas turbine and 900°C heat by a topping heater. The heater couples via a heat transport loop to industrial facility that consumes the high temperature heat to yield heat product such as hydrogen fuel, steel, or chemical. Original control methods are proposed to automate transition between the load duties. Equipment challenges are addressed for severe operation conditions. Performance limits of cogeneration load following are quantified from the plant system simulation to a range of bounding events including a loss of either load and a rapid peaking of electricity.     

Low exergy reactor for decentralized energy utilization

A new conceptual reactor named ‘low exergy nuclear reactor (LER)’ was proposed and its possibility was discussed qualitatively. The LER is defined by the reactor that generates low-exergy energy at a temperature near environmental temperature between about 100°C and 300 °C, which is lower than the output temperature of the energy generated by the conventional light water reactors (LWR). The necessity of the LER was discussed based on the present energy technology trend. Cogeneration systems based on the LER combined with absorption heat pump, thermoelectric device and steam turbine were proposed for decentralized energy utilization. The enthalphy balance of those decentralized energy supply systems was evaluated using practical data. The thermal efficiency of the LER system was compared with that of conventional LWR system. The LER system was expected to be suitable for a decentralized heating and cooling system.     

A very small LWR installed in the underground in the city

The effective of the nuclear reactor as the source of heat supply is more expected considering that the energy demand will increase and that the energy consumption structure will convert in Japan. The output scale of such reactors is to be less than 300MWt from the limit of supply area. We are studying two types of such reactors. One is the system for district heat supply with a nuclear reactor MR100 type and the other is for heat supply in buildings with a cassette type nuclear reactor MR1. The conception of these nuclear reactors is originated from the marine nuclear reactor technology. They are of highly safety with passively safe system and highly load following ability.     

Role of Nuclear Power in World Energy Production in the 21st Century

World growth of energy consumption in the 21st century is unavoidable. The most intense growth will occur in the developing countries. Of course, fossil fuels will continue to serve as the main source of energy, but the problems due to the growth of the raw materials base will also increase. The growth of nuclear power production will facilitate a successful solution to these problems. Various estimates show that by mid-century nuclear power will grow by a factor of four or five from the present level. Under such conditions, the solution of certain internal problems of nuclear power, such as preventing proliferation, handling spent fuel and radioactive wastes, and developing a reliable intrinsic raw materials base based on a closed fuel cycle and innovative nuclear technologies, will be exceedingly important for large-scale nuclear power to be successful. In this article, an assessment of the possible role of nuclear power in providing for the stable advancement of human civilization on global and regional scales is made on the basis of predictions of the growth of power production. __________ Translated from Atomnaya Energiya, Vol. 99, No. 5, pp. 323–336, November, 2005.