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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.
T. H. Trumbull, D. R. Harris
Nuclear Technology | Volume 154 | Number 1 | April 2006 | Pages 117-127
Technical Paper | Radiation Measurements and Instrumentation | doi.org/10.13182/NT06-A3722
Articles are hosted by Taylor and Francis Online.
Measurements of delayed fission product gamma-ray transmission through low-enriched UO2 fuel pin lattices in an air medium were conducted at the Rensselaer Polytechnic Institute Reactor Critical Facility (RCF). The RCF core consists of excess Special Power Excursion Reactor Test fuel pins enriched to 4.81 wt% 235U and clad in stainless steel. An experimental apparatus was constructed to hold various arrangements of fuel pin lattices. The arrangements consisted of a single activated source pin taken from the reactor core surrounded by inactive fuel pins in an air medium. A sodium-iodide detector and gamma-ray spectroscopy system was used to generate a pulse-height spectrum of the gamma-ray radiation for detector positions outside the lattice. The change in radiation intensity as the detector is rotated about the vertical axis of the lattice, the "channeling effect," was measured. Measurements of the channeling effect were performed for six experimental arrangements: 3 × 3, 5 × 5, and 7 × 7 lattices, with both the corner and the center positions containing the activated pin. The results of the measurements demonstrate that the gamma-ray radiation intensity can vary widely as a function of angle relative to the angle of rotation about the vertical axis of the lattice.