Thorium has been considered an excellent nuclear energy alternative for decades. It’s hard to believe the safety and efficiency benefits have not led to more popular use of thorium reactors — but there are reasons for that. Put simply, thorium-based reactors are still not economically viable for the most part. Uranium has benefited from decades of research, development and infrastructure thanks to its dual applications in weapons and energy during the Cold War. This research has allowed countries to establish protocols, infrastructure and knowledge bases that make uranium-based energy an easier option. The result is that at least for now, thorium reactors are unlikely to gain the upper hand over uranium oxide reactors. It’s possible that thorium reactors could become more dominant in the future, but a lot of work will have to be done to get to that point.