Small modular reactors: economic, safety, and environmental aspects

The interest in small modular reactors (SMRs) is long-standing and growing due to their unique characteristics (in primis size and modular approach) and the different possible applications (e.g., electrical, heat, hydrogen production, seawater desalination). The first part of this chapter focuses on the economics of SMRs. SMRs are often considered less competitive than large reactors due to a misguided idea related to the economy of scale principle (i.e., the bigger the better). However, as detailed in this chapter, SMRs present unique benefits primarily associated with modularization and modularity that, in some scenarios, could overcome the lack of economy of scale. The second part of this chapter deals with the safety and environmental aspects of SMRs, introducing some key safety features of SMRs. It includes the concepts of integral and simplified design while developing the concept of “passive safety” considering different reactor technologies. Additionally, the approach of defense-in-depth is explored and developed in the case of SMRs. Furthermore, the second part of this chapter presents relevant aspects related to the environmental impact of SMRs, highlighting the importance of considering the emissions during the operational period. The second part ends with a description of the radioactive waste produced by SMRs. The last section of the chapter discusses SMR deployment and introduces a novel approach—called the “System of Provision” (SoP) approach—supporting the decision-making process of a country evaluating the opportunity to develop a series of SMRs (or nuclear power plants in general).