Chapter 14: Nuclear Applications – Seawater Desalination

This chapter was published on “Inuitech – Intuitech Technologies for Sustainability”
on February 6, 2012

 Seawater desalination is one of the advanced applications of nuclear energy.

Global shortage of potable water is a real calamity. Here are some limitations and realities associated with potable water that unfortunately, cannot be disregarded. According to the International Atomic Energy Agency (IAEA), nearly three quarters of the earth’s surface are covered with water. The estimated total volume of water is 1.3 x 1018 m3. However, 97.5 percent of this amount is represented by the oceans, which are highly saline and unfit for human consumption. Of the remaining 2.5 percent, a major portion is locked up in polar ice and glaciers. On balance, less than 1 percent is available for human use. It is estimated that the amount of fresh water that is readily accessible to human use is about 9 x 1012 m3 and another 3.5 x 1012 m3 is captured and stored by dams and reservoirs.

Global population is growing at a phenomenal rate and so is the demand for drinking water. A recent United Nations’ report predicted that by 2050, the world’s population would reach about 9.3 billion, with most of the population growth occurring in Asia and Africa.

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Global Industry Analysts (GIA) announced in 2010 the release of a comprehensive global report on Water Treatment Equipment and Supplies market. The global market for Water Treatment Equipment and Supplies market is projected to reach $38.2 billion by the year 2015, driven by growing demand for fresh potable water from an expanding global population. The chronic shortage of freshwater is expected to become intense in the coming years, a factor that is likely to drive growth in the global water treatment market. Further, the trend towards industrialization and urbanization and intensifying agricultural operations are contributing to the enhanced demand for fresh water, thereby contributing to increased demand for water treatment products.

It is recognized that for human life a sufficient amount of water of adequate quality is essential. Unfortunately, every year new countries around the world are suffering from the shortage and affected by growing water problems. According to the World Health Organization (WHO) at any time, up to half of humanity has one of the six main diseases – diarrhea, schistosomiasis, or trachoma, or infestation with Ascaris, guinea worm, or hookworm – associated with poor drinking water and inadequate sanitation. About 5 million people die each year from poor drinking water, poor sanitation, or a dirty home environment – often resulting from water shortage.

A study conducted by IAEA in 2006 showed that 2.3 billion people live in water-stressed areas, 1.7 billion of them having access to less than 1,000 m3 of potable water per year. The United Nations Education, Scientific and Cultural Organization (UNESCO) reported in 2002 that the freshwater shortfall worldwide was then running at some 230 billion m3/yr and would rise to 2000 billion m3/yr by 2025. Now that the global population has grown to 7 billion, these figures must have been increased substantially and it will continue to increase due to population growth relative to water resources.

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With predictions that more than 3.5 billion people will live in areas facing severe water shortages by the year 2025, the challenge is to find an environmentally benign way to remove salt from seawater. Scientists are convinced that global climate change, desertification, and over-population are already taking their toll on fresh water supplies. In coming years, fresh water could become a rare and expensive commodity. Desalination is considered a leading solution to the world’s shortage of water. It helps filtered and distilled ocean water into drinking water.

Most desalination plants today use fossil fuels, and thus contribute to increased levels of greenhouse gases. Total world capacity is approaching 40 million m³/day (14,600 GL/yr) of potable water, in some 15,000 plants. Most of these are in the Middle East and North Africa, using distillation processes. The largest plant produces 454,000 m³/day (166 GL/yr). Two thirds of the world capacity is processing seawater, and one-third uses brackish artesian water. However, the process demands a huge amount of energy and specialized equipment, which is very expensive.

Large-scale commercially available desalination processes can generally be classified into two categories: (a) Distillation processes that require mainly heat plus some electricity for ancillary equipment, and (b) Membrane processes that require only electricity to provide pumping power. The energy for these plants is generally supplied in the form of either steam or electricity using fossil fuels. The intensive use of fossil fuels raises environmental concerns, and many countries are therefore considering the introduction of a nuclear power program or expansion of their existing nuclear power program.

At the April 2010 Global Water Summit in Paris, the prospect of desalination plants being co-located with nuclear power plants was supported by leading international water experts.

The World Nuclear Association reported that the feasibility of integrated nuclear desalination plants has been proven with over 150 reactor-years of experience, chiefly in Kazakhstan, India and Japan. Large-scale deployment of nuclear desalination on a commercial basis will depend primarily on economic factors. Indicative costs are US$ 70-90 cents per cubic metre, much the same as fossil-fuelled plants in the same areas. Slide3

One obvious strategy is to use power reactors, which run, at full capacity, but with all the electricity applied to meeting grid load when that is high and part of it to drive pumps for Reverse Osmosis (RO) desalination when the grid demand is low. RO is driven by electric pumps, which pressurize water and force it through a membrane against its osmotic pressure:

  • The BN-350 fast reactor at Aktau, in Kazakhstan, successfully supplied up to 135 MWe of electric power while producing 80,000 m³/day of potable water over some 27 years, about 60% of its power being used for heat and desalination. The plant was designed as 1000 MWt but never operated at more than 750 MWt, but it established the feasibility and reliability of such cogeneration plants. In fact, oil/gas boilers were used in conjunction with it, and total desalination capacity through ten Multi-Effect Distillation (MED) units was 120,000 m³/day;
  • In Japan, some ten desalination facilities linked to pressurized water reactors operating for electricity production yield some 14,000 m³/day of potable water, and over 100 reactor-years of experience have accrued. MSF was initially employed, but MED and RO have been found more efficient there. The water is used for the reactors’ own cooling systems;
  • India has been engaged in desalination research since the 1970s. In 2002, a demonstration plant coupled to twin 170 MWe nuclear power reactors (PHWR) was set up at the Madras Atomic Power Station, Kalpakkam, in southeast India. This hybrid Nuclear Desalination Demonstration Project (NDDP) comprises a reverse osmosis (RO) unit with 1800 m3/day capacity and a multi-stage flash, Multi-Stage Flash (MSF), a thermal process plant unit of 4500 m³/day costing about 25 percent more, plus a recently added barge-mounted RO unit. This is the largest nuclear desalination plant based on hybrid MSF-RO technology using low-pressure steam and seawater from a nuclear power station. They incur a 4 MWe loss in power from the plant. In 2009, a 10,200 m3/day MVC plant was set up at Kudankulam to supply fresh water for the new plant. It has four stages in each of four streams. An RO plant there supplies the plant’s township. A low temperature (LTE) nuclear desalination plant uses waste heat from the nuclear research reactor at Trombay has operated since about 2004 to supply make-up water in the reactor;
  • Pakistan in 2010 commissioned a 4800 m3/day MED desalination plant, coupled to the Karachi Nuclear Power Plant (KANUPP, a 125 MWe PHWR) near Karachi. It has been operating a 454 m3/day RO plant for its own use; and
  • China Guangdong Nuclear Power has commissioned a 10,080 m3/day desalination plant at its new Hongyanhe project at Dalian in the northeast.

Large-scale deployment of nuclear desalination on a commercial basis will depend primarily on economic factors. The IAEA is fostering research and collaboration on the issue.

  • The BN-350 fast reactor at Aktau, in Kazakhstan, successfully supplied up to 135 MWe of electric power while producing 80,000 m³/day of potable water over some 27 years, about 60% of its power being used for heat and desalination. The plant was designed as 1000 MWt but never operated at more than 750 MWt, but it established the feasibility and reliability of such cogeneration plants. In fact, oil/gas boilers were used in conjunction with it, and total desalination capacity through ten Multi-Effect Distillation (MED) units was 120,000 m³/day;
  • In Japan, some ten desalination facilities linked to pressurized water reactors operating for electricity production yield some 14,000 m³/day of potable water, and over 100 reactor-years of experience have accrued. MSF was initially employed, but MED and RO have been found more efficient there. The water is used for the reactors’ own cooling systems;
  • India has been engaged in desalination research since the 1970s. In 2002, a demonstration plant coupled to twin 170 MWe nuclear power reactors (PHWR) was set up at the Madras Atomic Power Station, Kalpakkam, in southeast India. This hybrid Nuclear Desalination Demonstration Project (NDDP) comprises a reverse osmosis (RO) unit with 1800 m3/day capacity and a multi-stage flash, Multi-Stage Flash (MSF), a thermal process plant unit of 4500 m³/day costing about 25 percent more, plus a recently added barge-mounted RO unit. This is the largest nuclear desalination plant based on hybrid MSF-RO technology using low-pressure steam and seawater from a nuclear power station. They incur a 4 MWe loss in power from the plant. In 2009, a 10,200 m3/day MVC plant was set up at Kudankulam to supply fresh water for the new plant. It has four stages in each of four streams. An RO plant there supplies the plant’s township. A low temperature (LTE) nuclear desalination plant uses waste heat from the nuclear research reactor at Trombay has operated since about 2004 to supply make-up water in the reactor;
  • Pakistan in 2010 commissioned a 4800 m3/day MED desalination plant, coupled to the Karachi Nuclear Power Plant (KANUPP, a 125 MWe PHWR) near Karachi. It has been operating a 454 m3/day RO plant for its own use; and
  • China Guangdong Nuclear Power has commissioned a 10,080 m3/day desalination plant at its new Hongyanhe project at Dalian in the northeast.

Large-scale deployment of nuclear desalination on a commercial basis will depend primarily on economic factors. The IAEA is fostering research and collaboration on the issue.

A broad spectrum of nuclear reactors is available today. In principle, all nuclear power reactors are capable of providing energy for desalination processes. Due to their typically low working temperatures, dedicated heating reactors can be combined with distillation processes. Furthermore, as nuclear reactors show their highest efficiency in base load operation and desalination is a base load process, nuclear desalination seems to have inherent advantages over other energy options. Here is the contribution of small nuclear reactors to seawater desalination:

  • SMART: South Korea has developed a small nuclear reactor design for cogeneration of electricity and potable water. The 330 MWt SMART reactors (an integral PWR) have a long design life and needs refueling only every 3 years. The main concept has the SMART reactor coupled to four MED units, each with thermal-vapour compressor (MED-TVC) and producing total 40,000 m3/day, with 90 MWe;
  • CAREM: Argentina has designed an integral 100 MWt PWR suitable for cogeneration or desalination alone;
  • NHR-200: China’s INET has developed this, based on a 5 MW pilot plant;
  • Floating nuclear power plant (FNPP) from Russia, with two KLT-40S reactors derived from Russian icebreakers, or other designs for desalination. If primarily for desalination, the twin KLT-40 set-up is known as APVS-80. ATETs-80 is a twin-reactor cogeneration unit using KLT-40 and may be floating or land-based, producing 85 MWe plus 120,000 m3/day of potable water;
  • The small ABV-6 reactor is 38 MW thermal, and a pair mounted on a 97-metre barge is known as Volnolom floating NPP, producing 12 MWe plus 40,000 m3/day of potable water by reverse osmosis; and
  • A larger concept has two VBER-300 reactors in the central pontoon of a 170 m long barge, with ancillary equipment on two side pontoons, the whole vessel being 49,000 dwt. The plant is designed to be overhauled every 20 years and have a service life of 60 years. Another design, PAES-150, has a single VBER-300 unit on a 25,000 dwt catamaran barge.

Here are new desalination projects/initiatives in progress:

Slide4

  • Algeria has undertaken a study on nuclear power generation and desalination using RO and MED. The country is also considering a 150,000 m3/day MSF desalination plant for its second-largest town, Oran (though nuclear power is not a prime contender for this). It is also building a 500,000 m3/d plant at Magtaa to start in 2012, and commissioned a 120,000 m3/d plant at Fouka near Algiers in 2011;
  • China is looking at the feasibility of a nuclear seawater desalination plant in the Yantai area of Shandong Peninsula, producing 80-160,000 m3/day by MED process, using a 200 MWt NHR-200 reactor. Another project is for a 330,000 m3/day plant near Daya Bay;
  • Egypt has undertaken a feasibility study for a cogeneration plant for electricity and potable water at El-Dabaa, on the Mediterranean coast. In 2010 plans were being formed for four 1000 MWe-class reactors to be built there and coming on line 2019-25, with significant desalination capacity;
  • In India, further plants delivering 45,000 m3 per day are envisaged, using both MSF and RO desalination technology, and building on the extensive experience outlined above. The 100,000 m3/d Nemmeli desalination plant is due for completion in December 2011, and a 200,000 m3/d plant is planned for Pattipulam nearby, both serving Chennai;
  • Indonesia: South Korea investigated the feasibility of building a SMART nuclear reactor with cogeneration unit employing MSF desalination technology for Madura Island, and later studies have been on larger-scale PWR cogeneration in Batan;
  • Jordan has a “water deficit” of about 1.4 million m3 per day and is actively looking at nuclear power to address this, as well as supplying electricity;
  • Kuwait has been considering cogeneration schemes up to a 1000 MWe reactor coupled to a 140,000 m3/day desalination plant;
  • Libya: in mid-2007 a memorandum of understanding was signed with France related to building a mid-sized nuclear plant for seawater desalination. Areva TA would supply this. Libya is also considering adapting the Tajoura research reactor for a nuclear desalination demonstration plant with a hybrid MED-RO system;
  • Morocco has completed a pre-project study with China, at Tan-Tan on the Atlantic coast, using a 10 MWt heating reactor which produces 8000 m3/day of potable water by distillation (MED). The government has plans for building an initial nuclear power plant in 2016-17 at Sidi Boulbra, and Atomstroyexport is assisting with feasibility studies for this;
  • Qatar has been considering nuclear power and desalination for its needs which are expected to reach 1.3 million m3 per day in 2010;
  • Tunisia is looking at the feasibility of a cogeneration (electricity-desalination) plant in the southeast of the country, treating slightly saline groundwater; and
  • In the UK, a 150,000 m3/day RO plant is proposed for the lower Thames estuary, utilizing brackish water.

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Most or all these initiatives have requested technical assistance from IAEA under its technical cooperation project on nuclear power and desalination. A coordinated IAEA research project initiated in 1998 reviewed reactor designs intended for coupling with desalination systems as well as advanced desalination technologies. This programme, involving more than 20 countries, is expected to enable further cost reductions of nuclear desalination.

IAEA has recognized that interest in using nuclear energy for producing potable water has been growing worldwide in the past decade. This has been motivated by wide varieties of reasons, inter alia, from economic competitiveness of nuclear energy to energy supply diversification, from conservation of limited fossil fuel resources to environmental protection, and by nuclear technology in industrial development. IAEA feasibility studies, which have been carried out with participation of interested Member States since 1989, have shown that nuclear desalination of seawater is technically and economically viable in many water shortage regions. In view of its perspectives, several Member States have, or are planning to launch, demonstration programmes on nuclear desalination.

The report suggests that desalination is an intensive energy process. Selection of most appropriate desalination process depends on various factors, among which is the evaluation of:

  • Available water resources (in terms of quantity and quality);
  • Available energy resources (including cost of energy: residual steam, waste heat, electricity, etc.);
  • Optimum co-generation scheme (with technical and economic considerations);
  • Overall cost of distribution (including cost for water transport and co-location);
  • Plant capacity and expected availability;
  • Sitting of the plant (including co-location option with nuclear power plant);
  • Technology assessment (including selection of materials for construction, equipment, plant life time, etc.);
  • Safety of coupling and of water product; and
  • Environmental impact assessment of the nuclear desalination plant.

Steps to launch a nuclear desalination project are more complicated than launching a typical desalination project. Yet, in both cases, the above steps should be considered in details, as they are prime elements of the technical and economic feasibility report.

In summary, commercial seawater desalination processes that are proven and reliable for large-scale freshwater production are multi-stage flash (MSF) and multi-effect distillation (MED) for evaporative desalination and reverse osmosis (RO) for membrane desalination. Vapour compression (VC) plants based on thermal and mechanical vapour compression are also employed for small and medium capacity ranges. These processes have their inherent advantages and disadvantages. For desalination plants rated at more than 4000 m3/d per unit, MSF is still more prevalent than any other process. However, the RO process is increasing its market share every year, and there is likely to be increased use of MED and VC, including hybrid systems.

In the final analysis, those countries suffering from scarcity of water are, generally, not the holders of nuclear technology, do not generally have nuclear power plants, and do not have a nuclear power infrastructure. The utilization of nuclear energy in those countries will require infrastructure building and institutional arrangements for such things as financing, liability, safeguards, safety, and security and at the same time will require addressing the acquisition of fresh fuel and the management of spent fuel.

Resources:

  1. Water Online – Global Water Treatment Equipment;
  2. World Nuclear Association – Nuclear Desalination;
  3. IAEA – Advanced Applications of Water Cooled Nuclear Power Plants;
  4. IAEA – Introduction of Nuclear Desalination – A Guidebook; and
  5. IAEA – Introduction of Nuclear Desalination.

 

 

 

 

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