Modular manufacture and construction of small nuclear power generation systems

Nuclear power is a stable, secure, low-carbon energy source; however, recent nuclear power plant projects are challenged by long build times and high construction costs, making them difficult to finance. Small Modular Reactors (SMRs) are nuclear reactors smaller than 300 MWe and claim to leverage manufacturing principles and modular build to resolve these issues and help improve the competitiveness of nuclear power. This project investigates modular build in a nuclear context, explores modularisation principles and best practises in other industries, identifies key constraints and optimisation criteria, and develops a new conceptual framework for modularising nuclear plants based on their size and subject to transport constraints. Transportation limits the type and amount of construction work that can be moved off-site. Due to their smaller size, up to 80% of a SMR plant can be modularised and transported by road, compared to only 20% for large reactors. Schedule and cost benefits are maximised when at least 60% of in-situ work is moved off-site, favouring fully modular units smaller than 600 MWe. Stick-built SMRs are not competitive with large reactors on the basis of their construction cost. A fully modularised SMR, however, can move 50% of its overnight construction cost off-site, achieving costs of $5,470/kWe (300 MWe SMR), competitive with the reference $6,000/kWe cost for a stick-built large reactor. Build schedule indirectly impacts construction cost by affecting overheads and interest during construction. Modular SMRs have the greatest scope for schedule reduction, moving 30% of in-situ time off-site and reducing build time to 3.5 years (300 MWe SMR), compared to 6.5 years for stick-built large reactors. Production learning is also critical to SMR economics and, when coupled with shorter build schedules, significantly impacts SMR total capital investment costs. A standardised series of modular SMRs can reach total capital costs of $4,600/kWe (300 MWe SMR) and can compete with the $4,400/kWe benchmark for energy technologies. SMRs have a unique opportunity to utilise modularisation and this project shows how they can leverage modular build to improve the economic competitiveness of nuclear power.