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2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
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The journey of the U.S. fuel cycle
Craig Piercycpiercy@ans.org
While most big journeys begin with a clear objective, they rarely start with an exact knowledge of the route. When commissioning the Lewis and Clark expedition in 1803, President Thomas Jefferson didn’t provide specific “turn right at the big mountain” directions to the Corps of Discovery. He gave goal-oriented instructions: explore the Missouri River, find its source, search for a transcontinental water route to the Pacific, and build scientific and cultural knowledge along the way.
Jefferson left it up to Lewis and Clark to turn his broad, geopolitically motivated guidance into gritty reality.
Similarly, U.S. nuclear policy has begun a journey toward closing the U.S. nuclear fuel cycle. There is a clear signal of support for recycling from the Trump administration, along with growing bipartisan excitement in Congress. Yet the precise path remains unclear.
M. E. Rivarola, P. C. Florido, D. O. Brasnarof, K. H. Kyung, L. Juanicó, J. Bergallo, J. Gonzalez, H. Daverio
Nuclear Technology | Volume 154 | Number 3 | June 2006 | Pages 361-373
Technical Paper | Enrichment | doi.org/10.13182/NT06-A3740
Articles are hosted by Taylor and Francis Online.
The SIGMA technology, a patented new concept for uranium enrichment based on the well-known gaseous diffusion (GD) method, has been developed by the Comisión Nacional de Energia Atómica in Argentina to be an alternative to compete in the uranium enrichment market. The SIGMA engineering approach stands on the integration of several GD stages in one module, with all the stages sharing one single multiflux compressor, one vessel, and a gas turbine. This arrangement, together with the use of the double-diffuser cascade configuration to increase the separative gain, leads to a breakthrough in the capital cost structure of the GD technology and a significant reduction in the energetic and operation costs. With the SIGMA concept, a leveled separative work unit cost that could be almost half the price of the present enrichment market level can be achieved. The SIGMA technology has also been conceived to incorporate proliferation-resistant features, and it has a very small overall proliferation risk. In this work we present the main features of the SIGMA technology, and we formulate a calculation scheme for the overall design analysis. We present some of the results of this investigation, including the SIGMA scale economy, and its comparison with others enrichment technologies.