Development of a new extraction system for selective americium separation from spent nuclear fuels

Nuclear energy is widely used as a source of green energy, but has as a drawback
the production of nuclear waste. This waste remains dangerous over a time frame of hundreds of thousands of years, making deep underground storage the only practical solution for this waste. However, the time frame over which this waste remains dangerous could theoretically be reduced to as little as ca. 300 years through a strategy called “partitioning and transmutation”. This strategy focuses on a small group of elements, the actinides, which are responsible for most of the long-term radioactivity. The goal of this strategy is to separate the actinides from the nuclear waste (partitioning) and then “burn” these in nuclear reactors (transmutation). The actinides present in nuclear waste are uranium, plutonium, neptunium, americium, and curium, and a well-developed separation process already exists for the first two of these, while for the remaining actinides development is ongoing. This work focuses on americium specifically, and developed a selective separation process for it based on the “AmSel” process. The AmSel process had the drawback of containing sulfur, which can end up in the transmutation targets and interfere with the transmutation process.
To limit contamination of the the targets, the new process is made up exclusively of chemicals containing only carbon, hydrogen, oxygen, and nitrogen, which are fully incinerable. Furthermore, we found that by taking the diglycolamide extractant used in the AmSel process, and making it unsymmetrical, performance could be improved.