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Conference Spotlight
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.
Kiyoshi Takeuchi, Shun-ichi Tanaka
Nuclear Science and Engineering | Volume 90 | Number 2 | June 1985 | Pages 158-164
Technical Paper | doi.org/10.13182/NSE85-A17673
Articles are hosted by Taylor and Francis Online.
Gamma-ray exposure buildup factors are calculated using a discrete ordinates direct integration code, PALLAS-PL, SP-Br, for water, concrete, iron, and lead for point isotropic sources. These data include the effects of secondary photon sources arising from Compton scattering, bremsstrahlung, and annihilation. Comparisons of these results without bremsstrahlung to values obtained earlier by moments calculations show reasonable agreement, except in some instances of deep penetration. The calculated buildup factors are tabulated for incident energies of 0.1 to 15 MeV (except for lead, where the lower energy is 0.4 MeV) and for penetration depths as great as 40 mfp.
