Closing the Nuclear Fuel Cycle with a Simplified Minor Actinide Lanthanide Separation Process (ALSEP) and Additive Manufacturing

Expanded low-carbon baseload power production through the use of nuclear fission can be enabled by recycling long-lived actinide isotopes within the nuclear fuel cycle. This approach provides the benefits of (a) more completely utilizing the energy potential of mined uranium, (b) reducing the footprint of nuclear geological repositories, and (c) reducing the time required for the radiotoxicity of the disposed waste to decrease to the level of uranium ore from one hundred thousand years to a few hundred years. A key step in achieving this goal is the separation of long-lived isotopes of americium (Am) and curium (Cm) for recycle into fast reactors. To achieve this goal, a novel process was successfully demonstrated on a laboratory scale using a bank of 1.25-cm centrifugal contactors, fabricated by additive manufacturing, and a simulant containing the major fission product elements. Americium and Cm were separated from the lanthanides with over 99.9% completion. The sum of the impurities of the Am/Cm product stream using the simulated raffinate was found to be 3.2 × 10−3 g/L. The process performance was validated using a genuine high burnup used nuclear fuel raffinate in a batch regime. Separation factors of nearly 100 for 154Eu over 241Am were achieved. All these results indicate the process scalability to an engineering scale

Advanced TALSPEAK for separating trivalent actinides and lanthanides

An Advanced TALSPEAK (trivalent actinide-lanthanide separations by phosphorus-reagentextraction from aqueous complexes) concept is being developed that uses2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]) to selectively extract trivalentlanthanide (Ln) ions in preference to trivalent actinide (An) ions. The An ions are held in theaqueous phase by complexing with N-(2-hydroxyethyl)-ethylenediamine-N,N',N'-triacetic acid(HEDTA). The primary advantage of the Advanced TALSPEAK system compared to thetraditional TALSPEAK system is that it is much less sensitive to the aqueous solution pH. For thisreason, it is viewed as being much more robust for industrial application. In this paper, wedescribe the basic principles of the Advanced TALSPEAK system, as well as experimentsconducted to explore the sensitivity of the process to minor changes in the process conditions(for example, changes in the pH, the HEDTA concentration, etc.). The latter experimentsshowed that the Advanced TALSPEAK system can be expected to be robust in a plant setting. Aflowsheet has been developed and a counter-current flow test using a surrogate feed isdiscusse