The Nuclear Decarbonization Option: Profiles of Selected Advanced Reactor Technologies

We live in a world divided by many issues, but most policy-makers accept the basic premise that increasing the availability of affordable low-carbon energy would make the world healthier, wealthier, and safer. Conventional fuel delivery systems are strained in many regions, the global geopolitics of energy supply are fraught, and carbon dioxide emissions, despite decades of debate since Rio and Kyoto, are rising faster now than at any point in history. And still, billions remain without regular access to electricity and mobility.

Nuclear energy provides more than 40 percent of all low-carbon electricity generated in the world today. That contribution could grow, but public perceptions of safety remain a key challenge–particularly post-Fukushima–and competitive costs, as always, will be paramount. In order to assess the impact that advanced technologies could play in the development and deployment of new nuclear reactor designs, the Clean Air Task Force asked several national leaders in nuclear technology to give us their perspectives on key policy-relevant issues.

We asked Dr. Ted Marston, former Chief Technology Officer of the Electric Power Research Institute, to write for us on small, modular light water reactors (smLWRs). Dr. Andrew Kadak, former Professor of the Practice in Nuclear Engineering at the Massachusetts Institute of Technology, examines the prospects for high-temperature gas-cooled reactors (HTGRs). And Dr. Per Peterson, Chair of the Nuclear Engineering Department at University of California, Berkeley, explores the future of some fluoride molten salt reactors (called FHRs).

Their conclusions are important and offer reasons for optimism:

• Small, modular light water reactors (smLWRs): With modest development efforts, smLWRs, using fuel and systems quite similar to modern LWRs, could offer significantly enhanced safety over the existing nuclear fleet, deployment flexibility (e.g., staged investment and repurposing of some existing infrastructure), and potential cost-reductions through efficiencies of factory manufacturing.
• High-temperature gas-cooled reactors (HTGRs): HTGRs, using extremely heat-resistant, encapsulated fuel (already demonstrated in the United States and elsewhere) offer the possibility of nearly meltdown-proof reactors, higher thermal efficiencies, and expanded uses for nuclear energy (e.g., manufacturing of zero-carbon liquid transportation fuels), as well as many of the potential deployment and manufacturing advantages of smLWRs.
• Fluoride salt-cooled High temperature Reactors (FHRs): And FHRs, using the same heat-resistant, encapsulated fuel as HTGRs, but with coolants of dense molten salt compounds, could retain many of the advantages of HTGRs at a greatly reduced size, offering the potential for breakthrough economics if designs prove out.

For a world struggling to reduce carbon emissions while sustaining and increasing economic growth, and understandably concerned about the potential risks of nuclear energy, the advantages these advanced reactor designs offer could be profound. But bringing these concepts to commercial reality will require sustained development, especially for the more advanced concepts. Our hope is that these papers will help to inform the debate about how governments and the private sector should support that development.

This report does not aspire to cover the full scope of potentially important nuclear power technologies. Korean and Russian firms are developing smLWRs that could be important in some markets, and technologies that address the life-cycle of nuclear fuel and waste–including fast neutron reactors and thorium-based reactors–also could be important. More radical designs, such as the liquid fluoride thorium reactors (developed by Oak Ridge National Laboratory to use liquid fuels, rather than solid), may be able to provide even more dramatic advantages on safety, cost, and fuel cycle issues. Sub-critical reactors driven by particle accelerators may one day be able to convert low-value nuclear materials directly into energy. We will explore the potential of these technologies in future reports.