At present, nuclear is the world's second largest source of low-carbon power, and nuclear power plants provide roughly 10% of the global electricity supply. While deployment of conventional, light-water-cooled nuclear reactors has slowed in the United States in recent years, new nuclear power plants continue to be built elsewhere – primarily in China and other Asian countries. As older baseload generation assets are retired, electric companies may seek new generation options to meet future energy demands and achieve strategic sustainability (including decarbonization) goals. Conventional, water-cooled nuclear reactor designs remain the dominant nuclear technology option to date. However, advanced reactors (ARs) are expected by many researchers and analysts to emerge as viable options in the 2030s and 2040s, despite the need for continued development of reactor designs and considerable policy, regulatory, and market evolution.
ARs encompass three major categories of nuclear reactor designs. The first category is referred to as “evolutionary,” which generally includes water-cooled reactor designs that improve on existing conventional designs through small to moderate modifications to minimize technological risk. The second category is referred to as “revolutionary” or “innovative,” which captures designs that incorporate radical changes in the use of materials and/or fuels, operating environment and conditions, and system configurations. Revolutionary reactor designs are typically not water-cooled, and may be referred to as “Generation IV” reactors. Small modular reactors (SMRs) are the third category of ARs, and are scaled-down, modularly constructed and deployed versions of either water- or non-water-cooled reactor designs.
In summary, ARs employ a combination of new coolants, fuels, materials, and power conversion technologies that, if commercialized, could offer substantial improvements over existing generation technology in terms of safety, economics, performance, and long-term energy security. ARs, particularly non-water cooled reactor designs, may fundamentally transform the way nuclear reactors work, how they are built, what they cost, and how they may be operated with other assets. Nevertheless, ARs will likely face some of the same non-technical challenges that conventional technologies have faced – namely, stringent regulatory requirements, negative public perception, and high first-mover (customer and investor) risk relative to traditional electric generation technologies. Further, there is great uncertainty around costs of all ARs, particularly those that have not been commercially deployed yet.
This report provides a basic overview of nuclear technologies by “Generation,” including key distinctions between conventional reactor designs and ARs, as well as a discussion of selected technology and market statistics before discussing costs of selected ARs. This report concludes with a discussion of notable reactor designs and projects to monitor for planning purposes.