Thorium fuel cycle research and literature: Trends and insights from eight decades of diverse projects and evolving priorities

Literature on the thorium fuel cycle spanning eight decades from the 1940s to the 2010s is identified, categorized, and analyzed. The publications are divided among twelve topical categories, and overall thorium literature trends are evaluated using database analysis techniques. In total, 1449 publications are identified, with the most prevalent topics being Reprocessing and Waste Management, Molten Salt Reactors, Fuels, and Light Water Reactors. In aggregate, reactor-oriented categories (five in all) comprise 45.5% of publications. The US is the most dominant thorium-publishing nation with 916 publications, followed next by India with 82 and then eight other countries having 25 publications or more. National laboratories have contributed 45% of thorium publications, with roughly equal shares of the balance split between government agencies, universities, and corporations/companies. Oak Ridge National Laboratory in the US accounts for more than a quarter of all publications. Specialized criteria are developed and applied to identify some of the most important, or “keystone”, publications for each category. Across the different categories, and for the study of thorium fuel cycles overall, published research reached an intermediate peak in the 1970s followed by a sharp decline in the 1980s and 1990s; however, interest has been revived moving into the 21st century.