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Laying the Foundation for Cleaner Nuclear Energy

AUTHOR: ND Staff

PUBLISHED: June 18, 2014

Peter C. Burns
Peter C. Burns, Massman Professor Civil and Environmental Engineering and Geological Sciences

All matter is composed of building blocks. The structures and shapes are different depending on the intended purpose and the materials being used. Uranium, the heaviest abundant element, is the current fuel used in almost all commercial nuclear reactors, but the nuclear waste produced is environmentally troubling. Peter C. Burns, the Massman Professor of Civil Engineering and Geological Sciences and Director of the Center for Materials Science of Actinides, and a team of University researchers have been focusing their efforts on uranium-based building blocks, specifically uranyl peroxide polyoxometalates, to provide a foundation of knowledge for a future advanced nuclear energy system.

Uranyl peroxide
Uranyl peroxide self-assembles into clusters with fullerene and other topologies that may be useful in the development of greener nuclear fuel cycles.

Centuries old, polyoxometalates are metal oxide clusters. They are often studied as a model for nano-structured materials and are useful as catalysts in several chemical systems. The structures that Burns’ team is creating are important because they hold promise for being about to change the behavior of uranium and other actinides used in the nuclear fuel recycling system. They could also be used to manufacture new nuclear fuels with nano-scale precision.

Notre Dame U60 Cluster
Shown here is the topology of the largest cluster the Notre Dame team has made (U60 as compared to a carbon buckyball (C60). The soccer ball like structure is the key to determining its behavior.

Actinides, such as uranium and neptunium, are ideal candidates for self-assembly into polyoxometalates. In fact, many of the clusters the Burns’ group has discovered exhibit fullerene topologies, meaning they are cage structures that feature 12 pentagons and an even number of hexagons. It is the structure of the cage and, most important, its symmetry that appears to determine the behavior of these clusters. Uranyl peroxide clusters can self-assemble in aqueous solutions. They can be maintained in the solution for several months, and they readily crystalize into extended structures that permit detailed structure characterization. Control of uranium behavior in water by cluster formation may be used to significantly reduce the amount of waste that will actually need to be stored, i.e., a greener fuel cycle that produces more energy without a proportional increase in waste production.

SUGGESTED READING

Sigmon, Gintry Versus Minimal Pentagonal Adjacencies in Uranium-based Polyoxometalate Fullerene Topologies” Angewandte Chemie International Edition, 2009, 48, 2737-2740ger E.; Unruh, Daniel K.; Ling, Jie; Weaver, Brittany; Ward, Matthew; Pressprich, Laura; Simonetti, Antonio; and Burns, Peter C., “Symme.

Sigmon, Ginger; Ling, Jie; Unruh, Daniel K.; Moore-Shay, Laura; Ward, Matthew; Weaver, Brittany; and Burns, Peter C., “Uranyl-Peroxide Interactions Favor Nanocluster Self-assembly” Journal of the American Chemical Society, 2009, 131 (46), 16648-16649.

Soderholm, L.; Almond, Philip M.; Skanthakumar, S.; Wilson, Richard E.; and Burns, Peter C., “The Structure of the Plutonium Oxide Nanocluster [Pu38O56Cl54(H2O)8]14-” Angewandte Chemie International Edition, 2008, 47, 298-302.

Forbes, Tori Z.; McAlpin, J. Gregory; Murphy, Rachel; and Burns, Peter C., “Metal-oxygen Isopolyhedra Assembled into Fullerene Topologies” Angewandte Chemie International Edition, 2008, 47, 2824-2827.