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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.
Byung-Ho Lee, Yang-Hyun Koo, Je-Yong Oh, Jin-Sik Cheon, Dong-Seong Sohn
Nuclear Technology | Volume 157 | Number 1 | January 2007 | Pages 53-64
Technical Paper | Fuel Cycle and Management | doi.org/10.13182/NT07-A3801
Articles are hosted by Taylor and Francis Online.
A fuel performance code, COSMOS, was developed for an analysis of the thermal behavior and fission gas release of both mixed-oxide (MOX) and UO2 fuels up to high burnup. The models have been improved for the fuel thermal conductivity, the fission gas release, and the cladding corrosion and creep. In particular, the thermal conductivity and fission gas release models were restructured with due consideration for the inhomogeneity of the MOX fuel. These improvements enhanced COSMOS's precision for predicting the in-pile behavior of the MOX fuel. The COSMOS code also extends its applicability to the sophisticatedly instrumented fuel test in a research reactor. With the improved models, the recent in-pile test results were analyzed and compared with the code's prediction. The database consists of the instrumented MOX fuel test in a research reactor, the postirradiation examination results after an irradiation in a commercial reactor, and a preliminary instrumented test in the HANARO reactor. With the rigorously characterized fabrication data and irradiation information, the COSMOS code predicted the in-pile behaviors well, such as the fuel temperature, rod internal pressure, fission gas release, and cladding properties of MOX and UO2 fuels. The estimations by COSMOS also demonstrated its applicability to the instrumented irradiation test.
