Nuclear energy has recently been confirmed as one of the key technologies required to fulfil energy transition pledges and targets. Small Modular Reactors (SMR) are indeed a principal element of the last years' "Nuclear Renaissance", where new design and execution models are being developed to achieve time and cost targets for nuclear power plant projects. The concept of SMR is not new and has already been adopted in the past, mainly for military applications. Today, it refers to a model aimed at effective cost and risk management as well as project control. The main characteristics of a Small Modular Reactor are the small size and the modular approach: modularity centralises the manufacture of components, allowing for mass production and standardisation; and small projects are aimed at easier cost and time control.
The SMR model includes the switch to a standardisation of the plant's project. The model of “First of a Kind” or “FOAK” describes the case where a single nuclear power plant (a unique plant with a customised design, tailored to a specific site) costs much more than later versions, named “Nth of a Kind” or “NOAK”. Each NOAK project will therefore have to keep the large majority of the FOAK Detailed Design results, drawings, technical specifications, and even supply-chain. Meanwhile, site-specific requirements, local national regulations and specific localised suppliers could differ, and they will require limited fine-tuning of the project.
The SMR concept is often coupled with the hybridisation of nuclear generation plants with other services, such as the concurrent generation of power with heat, hydrogen, or desalinated water. This approach has the additional purpose of providing flexibility in the nuclear plant operation on power grids influenced by non-programmable renewable energy sources.
A 340 MW SMR plant, hybridised with a reverse osmosis desalination system, can provide at least 800,000 m3/day of drinking water
One of the most promising uses of SMR is indeed for the desalination of seawater for agricultural, industrial or municipal uses. The water demand for drinking and industrial purposes has steadily increased during the last decades, following the fast development and urbanisation in areas such as the Middle East and due to the effect of climate change.
As an illustrative business case, a 340 MW SMR plant, hybridised with a reverse osmosis desalination system, can provide at least 800,000 cubic metres per day of drinking water, almost a fourth of the water used daily by Abu Dhabi City. A significant point for the economic evaluation of a possible investment is the suitable alignment of the expected lifetime of the desalination plant with respect to the SMR power plant's lifetime. Typical lifetime values are 60 years for the SMR and 30 years for the desalination plant. In the performed test analysis, a lifespan of 60 years has been adopted for the desalination plant, by following, for instance, a similar "modular" approach in the design of this asset (to increase serviceability) or a possible technology improvement, capable of reducing component degradation during the operation. The economic results of the analysis show that the plant could have a Simple Payback Time of 8.4 years with a Net Present Value (NPV) of US$3,153 million. The Levelized Operating Cost of water is estimated at US$0.68 per cubic metre. This water cost is in line with the price race observed in recent years in the Middle East region, where the production costs of water desalination continue to fall due to the combined effect of improvements in plant energy efficiency, economic support from low interest rates, and low-cost generation.
The poly-generation of electricity and desalinated water by SMR represents, therefore, a valuable path to efficiently increase the NPV by maintaining the investment payback time, while providing low-carbon power and cheap fresh water.
