Computational analysis of nuclear desalination system under various configurations

Nuclear desalination concept and implementation spanning 50 years are recognized as an economical viable option for water and electricity production but could not receive wider applications. This is due to various factors, in addition to technical design parameters, other factors, such as social, economic, and environmental issues, need to be considered. For this purpose, the current studies start with performing a critical and up-to-date literature review on previous investigations in the field of nuclear reactors and integrated nuclear power with desalination plants with a specific focus on performance criteria, technical specifications, etc. Reviewing and compiling the most updated technical specifications, cost estimations, and environmental data related to nuclear power and desalination plants are also important steps. Previous studies show a special focus on other important issues on nuclear desalination characteristics in countries including Saudi Arabia, Egypt, United Arab Emirates, Pakistan, India, and Kuwait. This work presents a concise review of previous works on the relevancy of other issues, such as economic, environmental, and social, associated with the use of nuclear energy in power generation and fresh water production. Preliminary assessment of possible hybrid configurations of nuclear and desalination technologies is developed and assessed by a computational program. Both operating and capital cost of the integrated plants are calculated. The simulation model is then extended to compare with other heating reactors as well for the verification analysis. The results obtained from comparative assessment depicts the accuracy of the simulation model used for preliminary assessment of the integrated nuclear desalination option. The main objective of the research is to assess the nuclear desalination plant development in terms of social, economic and environmental aspects. The results will pave the way for countries interested in developing nuclear desalination plants.

Due to the high amount of natural gas resources in Iran, the gas cycle as one of the main important power production system is used to produce electricity. The gas cycle has some disadvantages such as power consumption of air compressors, which is a major part of gas turbine electrical production and a considerable reduction in electrical power production by increasing the environment temperature due to a reduction in air density and constant volumetric airflow through a gas cycle. To overcome these weaknesses, several methods are applied such as cooling the inlet air of the system by different methods and integration heat recovery steam generator (HRSG) with the gas cycle. In this paper, using a heliostat solar receiver (HSR) in gas and combined cycles are investigated by energy, exergy, and economic analyses in Tehran city. The heliostat solar receiver is used to heat the pressurized exhaust air from the air compressor in gas and combined cycles. The key parameter of the three mentioned analyses was calculated and compared by writing computer code in MATLAB software. Results showed the use of HSR in gas and combined cycles increase the annual average energy efficiency from 28.4% and 48.5% to 44% and 76.5%, respectively. Additionally, for exergy efficiency, these increases are from 29.2% and 49.8% to 45.2% and 78.5%, respectively. However, from an economic point of view, adding the HRSG increases the payback period (PP) and it decreases the net present value (NPV) and internal rate of return (IRR).

Nuclear power can be categorized as a clean energy source for producing electricity and supplying the required energy to a desalination plant, promising less atmospheric emission in comparison to fossil fuels. Considering the fact that fresh water-related issues are acute in many countries of the world, the utilization of desalination technologies seems to be the key solution to these problems. Desalination processes are known to be “energy-intensive”, emphasizing the potential advantages of its integration to a nuclear power plant in mediumto large-scale seawater desalination projects. The demand for electricity and fresh water in Iran compels the country to search for a feasible option. We suggest nuclear desalination as a suitable alternative, in which the recovered heat can be used in thermal desalination systems. In this article, the status of currently operating desalination plants and future developments are described. Several possible schemes for coupling nuclear power plant and fossil fuel-based plants with desalination technologies are suggested and some thermo-economic analysis (based on the specific characteristics of the country) are presented. Results of calculations reveal some advantages of nuclear desalination complex and its competitiveness with other options. It should be noted that the research has been conducted by cooperation of two SPbPU PhD students with Iranian citizenship.

The development of a small-sized nuclear heat-only plant with maximized safety features dedicated to seawater thermal desalination was proposed to address both a serious water crisis and nuclear safety issues, which continue to be perennial problems. In this study, the feasibility of a dedicated nuclear heat-only desalination system for a target country was evaluated in comparison with a target nuclear thermal desalination system. First, the target country was selected, and its current energy and desalination status was investigated. The suitable nuclear desalination options for the target country were then selected. Finally, using corresponding analysis tools, performance and economic analyses were conducted for a dedicated nuclear heat-only desalination system and the target nuclear thermal desalination system. The results of the analyses indicate that operating the small-sized nuclear heat-only plant at low pressures coupled with a seawater thermal desalination plant will considerably improve both the safety and economy without a significant loss in desalination performance. In conclusion, the proposed dedicated nuclear heat-only desalination system is expected to have high potential for solving both problems.

Nuclear energy is used to produce electricity; it can also be applied in a cogeneration process to produce power and heat. Nuclear energy is a very clean source as it produces almost no greenhouse gases, such as CO2. Under the Kyoto Protocol, the signatory countries committed themselves to reducing CO2 emissions; therefore, it is reasonable to take advantage of existing nuclear facilities to the greatest extent possible. This means that even though they were built only to produce electricity (Krško NPP, for example), they can also be used for other applications: a source of heat for district heating or desalination of sea water in areas at risk of a lack of drinking water. Nevertheless, the technology can be upgraded by using the experience of other nuclear power plants (NPPs) having similar district-heating systems. In this paper, the focus was on models of steam consumption from the secondary system of the Krško NPP for the Krško and Brežice district-heating purposes. The Krško NPP has a Westinghouse PWR with 2,000 MWt and an electrical power output of 696 MW to the grid. The technological part is divided into three main systems: primary, secondary and tertiary. The first two are sealed and isolated from the environment while the third, which uses water from the River Sava for cooling, is connected to the outside environment. This paper focuses on the technical solution to obtain heat from the NPP’s secondary system for district-heating purposes. According to thermodynamic calculations, the secondary system determines the reduction of produced electricity, when the steam is exploited in front of the turbine. This paper presents some technical, economic and safetysolutions for the highly efficient extraction of vapour for district heating. Furthermore, some thermodynamic calculations and technical solutions for district-heating purposes using the KrškoNPP for the Krško-Brežice area are shown.

Investigation of an integrated hydrogen production system based on nuclear and renewable energy sources: Comparative evaluation of hydrogen production options with a regenerative fuel cell system

A systematic approach for detection of malfunctions in equipment of nuclear desalination plants during operation

The Pumped Hydro Storage Plants and Their Civil Engineering Structures

Several ways to overcome dependence on fossil fuels/energy sources of petroleum for national energy procurement have been performed, such as replacing petroleum with liquid coal/gas, and other renewable energy such as hydrogen. This has been stated in the Government Regulation no. 79 of 2014 on National Energy Policy and Law no. 17 of 2007 on the 2005-2025 National Long-Term Plan. To support national energy growth, the government has enacted the use of new and renewable energy contributing to more than 23% of total energy consumption and that the use of oil should be reduced to less than 25%. Experimental Power Reactor or called Reaktor Daya Eksperimental (RDE) is built to demonstrate for electricity generation or cogeneration purpose, which utilizes nuclear heat for producing electricity and for providing process heat for an industry, for example desalination. Cogeneration system can also improve the economical benefit of the RDE by thermal utilization. Seawater desalination is an attractive solution, of which the technologies have been well established over the past 50 years. The two most commonly used desalination technologies are multistage flash (MSF) and reverse osmosis (RO) systems. Basically, almost all PLTUs in Indonesia have applied desalination technology to supply the process water needs, but they still use fossil energy to supply heat. In order to overcome electricity deficiency and water scarcity in some areas of Indonesia, then to accommodate a government regulation on energy mix, it is necessary to study nuclear heat utilization for desalination (Nuclear Desalination) through cogeneration system. The Nuclear Desalination is conducted by coupling the RDE with desalination units, so it can simultaneously produce electricity and freshwater. An intermediate heat exchanger is incorporated between the nuclear reactor and the desalination unit to ensure no radioactive contamination in secondary system or to protect the desalinated water. The objective of study is to choose the most optimum options of the steam extraction points that will be used for desalination process. The result of this study showed that heat can be extracted in the heat application line before the steam turbine (coupling option 1) and the downstream of steam turbine (coupling option 2). For coupling option 1, the steam (0.94 kg/s) with the temperature of 520°C can be extracted to produce a 27 m3/h fresh water. Meanwhile, using the low-pressure steam rejected from turbine (coupling option 2), the fresh water of 16.5 m3/h (396 m3/d) flow rate can be produced from the desalination unit.

A new design paradigm for nuclear power plants is needed to complement the increasing adoption of low marginal cost variable renewable energy resources. The situation is reflected in the wholesale electricity price–duration curve with four distinct economic opportunities: (a) a hundred or so hours per year of high-value peaking power; (b) about 4000–5000 h of moderate electric prices; (c) about 2000 h per year when renewables set the marginal price at or near zero; and (d) about 1000 h of flexible ramping between the b and c regions. The current approach to the low-carbon energy transition reduces the need for baseload power and requires curtailment of conventional, nuclear, and even renewable generation, decreasing their capacity factors and increasing their fixed charges for electricity generation. Flexible low-carbon dispatchable power plants capable of daily cycling along with storage and time shifting of low-cost nondispatchable renewable power will be needed. Although nuclear power plants have demonstrated load-following capability, cycling can be limited by reactor kinetics (xenon poisoning) as well as by thermal stresses and fatigue considerations in the steam cycle. Storage of nuclear heat is hampered by the relatively low operating temperatures of existing nuclear reactors (but not advanced reactors) that lowers thermal to electric conversion efficiency, which in turn increases the required quantity of storage medium and the cost of storage. The quantity of storage medium can be reduced by integration of thermal energy storage with high-grade heat as in the liquid salt combined cycle (LSCC). The LSCC uses high-temperature gas turbine exhaust heat to increase the electricity output per unit of storage medium, uses the stored energy to add operating flexibility to a bottoming steam cycle, and substantially reduces the fuel heat rate. The low fuel heat rate improves economic competitiveness compared to alternative gas turbine-based power plants, especially when burning expensive fuels such as hydrogen. LSCC could be coupled to a nuclear power plant for time shifting both nuclear and renewable electricity and could support high utilization of a co-located hydrogen electrolysis plant. Further cost reduction could be achieved by using solid media for thermal energy storage, with the liquid salt used as a heat transfer medium.

Improvement of the Decay Heat Removal Characteristics of the Generation IV Gas-cooled Fast Reactor

Desalination of sea water through thermal and membrane based techniques and production of hydrogen through low temperature water electrolysis at facilities co-located with nuclear power plants are two areas identified for deploying co-generation projects in India in the near term. Nuclear desalination meets the requirements of clean drinking water in and around the nuclear facility, as well as to the in-house demand for high purity water for steam generation and other processes like hydrogen generation, coupled to it. Nuclear assisted hydrogen production also provides means to generate and distribute clean hydrogen which is envisaged as an important component of the decarbonized energy system of the near future. Currently the technologies for indigenous design, manufacture and quality assurance of desalination and medium scale compact water electrolysis plants are commensurate with the 220 MW(e) PHWRs presently operating in India. This work provides an overview of the research, development and deployment work carried out in these two areas in India, analyses the applicability of the IAEA Milestones Approach to nuclear cogeneration projects and discusses the problems and prospects of setting up and integrating more such facilities all over the country.

Low energy desalination and wind energy — sustainable solutions for drinking water production

Economic evaluation of nuclear desalination systems

Possibilities are analyzed for improving the commercial attractiveness of nuclear electricity generation in market conditions. A model is presented in which a financially integrated electricity generating system comprising several units of one technological type, rather than a single unit, is subject to an economic analysis. Issues have been considered involved in the calculation of the electricity cost in such systems and their construction. It has been shown that the calculated unit cost of the electricity generated in a financially integrated nuclear energy system with the number of units being more than one, provided it is financed by shareholders and creditors, can be lower as compared with the cost of the electricity generated by power units, not integrated economically, of the same capacity under the same investment conditions.The effect is achieved thanks to the short-term crediting component in the electricity cost the funds on which can be returned, at a time, for a smaller number of units (even for only one), as electricity is produced by all units in the system. The results of the calculations for nuclear energy sources and combined-cycle plants using the developed model make it possible to conclude that the switch from economic models of individual nuclear units to models of integrated energy systems can bring the calculated economic performance of nuclear power closer to (or better) the performance of fossil-fuel energy sources. If achieved, this may increase the commercial attractiveness of nuclear power and contribute to a growth in the public and private investments in nuclear power business.