Nuclear Desalination Plant

Nuclear power as an energy source is seeing a huge resurgence worldwide. At the start of 2018, 449 reactors were operable across the globe, providing a total of 390 GW of electrical power. However, based on currently known reactor proposals and plans, the number of operable reactors in 25 years’ time is expected to surpass 600, supplying up to 650 GW of electricity. It is anticipated that up to 1000 GW of new nuclear capacity will be required by 2050 to manage carbon dioxide emissions, improve air quality, and provide reliable energy sources.

The energy production of nuclear plants has increased steadily over time, increasing revenues for plant operators according to an economy of scale. That is, it is possible to double the amount of energy generated without doubling the cost of production, and this has driven plant expansion since the first nuclear plants were constructed in the early 1950s. Today, the standard new nuclear power plant has a net capacity of 1000-1200 MW. However, the increasing size of plants has made them more complex, with longer construction times and greater construction costs. The costs to build a new two-reactor nuclear power station in the UK are approximately £20 bn, and nuclear is viewed by many investors as too risky, making it very difficult to finance these projects.

However, we are now seeing a paradigm shift in Plant economics. Technology developers are moving from an economy of scale to an economy of volume. Instead of building larger and larger reactors, there is increasing interest in mass-producing small modular reactors (SMRs) in factories, thus reducing project risks. With SMRs, single reactors can be used closer to where they are needed, or alternatively several small units can be sited together to meet larger power requirements. As such, SMRs have been proposed as a method for providing nuclear power to regions with dispersed populations, or low overall power needs, where a single large plant may not be appropriate. They have also been proposed to carry out other duties instead of, or in addition to electricity generation, such as providing high temperature heat for industrial processes, hydrogen production by thermochemical treatment or electrolysis of water, as a complement to energy storage solutions, or for the desalination of sea-water where potable water resources are limited.

Task

The small Pacific island nation of Popolopo, a Spanish overseas territory situated between Fiji and Samoa, has decided to install a small nuclear power plant to supply energy for a sea-water desalination facility. The Spanish government has approached several nuclear-powered nations to find a reactor vendor for the project, and several groups have responded to the invitation to tender with bids to supply a nuclear energy system. However, local expertise is limited, and so the government is not able to critically appraise the bids, nor to design a desalination facility. For this they have approached you.

Your team represents an engineering consultancy firm hired by the government of Popolopo to assess the bids from the various nuclear equipment vendors and select the most appropriate to construct their nuclear power system on the island.

The islanders have limited access to fresh water. There is enough water to drink, but this is insufficient for anything other than the most basic requirements. Out of necessity, water is strictly rationed by the government. The government requires that the nuclear-powered desalination plant be able to supply enough water to comfortably meet the needs of the population of 750,000 people. There should be sufficient capacity for expansion of the population and the development of industry over the lifetime of the plant.

The Popolopan reactor will be a first-of-a-kind technology demonstrator. If successful it is likely that other reactors of the same type will be constructed in Spain and elsewhere in the future.

Considerations

First and foremost, you will need to consider the Popolopan water needs, and how sea water can be processed to meet the requirements of the islanders. The method of water desalination should be matched to the seawater feed and fresh water product required both in terms of quality and quantity.

The island’s government are committed to the nuclear reactor plan, and so for political reasons, the plant must be powered by the nuclear power facility. You should consider the most appropriate way to use energy from a nuclear source to perform desalination, and whether given desalination and processing methods preclude the use of certain reactors, and vice versa. You will also need to ensure that your solution is appropriate, remembering that Popolopo has no existing nuclear infrastructure, so provision for all necessary support and accident scenarios must be considered. Consider also the group offering to supply the reactor technology, and whether they have the necessary experience and resources to deliver their design successfully.

Unlike the nuclear reactor design, which must be selected from the list of tenders that have been received, the desalination plant could be a commercial system or a novel or bespoke design. Your choice of desalination plant should safely and effectively meet the water needs of Popolopo. You will need to determine how much water you should aim to supply, what your method of desalination will be and which reactor is the best for this. When selecting a reactor, you should also consider the power rating, fuel type, regular outages for refuelling and regular fuel costs, proliferation risks, accident preparedness, technological readiness, and any other factors you deem relevant.

The initial outlay costs for the construction of the reactor are expected to be very high, and the Popolopan government will be able to shoulder the costs of construction. If you can develop a strong enough case to show that the nuclear-powered desalination facility will be successful, you may be able to convince investors to fund the project. The government of Popolopo would need to meet the long term costs of the project without additional input.

You should consider the sustainability effects of your plant, including economics, social effects, and environmental impact, both in the short and the long term.