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Meeting Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
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The U.S. Million Person Study of Low-Dose-Rate Health Effects
There is a critical knowledge gap regarding the health consequences of exposure to radiation received gradually over time. While there is a plethora of studies on the risks of adverse outcomes from both acute and high-dose exposures, including the landmark study of atomic bomb survivors, these are not characteristic of the chronic exposure to low-dose radiation encountered in occupational and public settings. In addition, smaller cohorts have limited numbers leading to reduced statistical power.
M. Hadj-Nacer, T. Manzo, M. T. Ho, I. Graur, M. Greiner
Nuclear Technology | Volume 194 | Number 3 | June 2016 | Pages 387-399
Technical Paper | doi.org/10.13182/NT15-82
Articles are hosted by Taylor and Francis Online.
A two-dimensional computational model of a loaded used nuclear fuel canister filled with dry helium gas was constructed to predict the cladding temperature during vacuum-drying conditions. The model includes distinct regions for the fuel pellets, cladding, and helium within each basket opening, and it calculates the conduction heat transfer within all solid components, heat generation within the fuel pellets, and conduction and surface-to-surface radiation across the gas-filled regions. First, steady-state simulations are performed to determine peak clad temperatures as a function of the fuel heat generation rate, assuming the canister is filled with atmospheric pressure helium. The allowable fuel heat generation rate, which brings the peak clad temperature to its limit, is evaluated. The discrete velocity method is then used to calculate slip-regime rarefied gas conduction across planar and cylindrical helium-filled gaps. These results are used to verify the Lin-Willis solid-gas interface thermal resistance model for a range of thermal accommodation coefficients α. The Lin-Willis model is then implemented at the solid-gas interfaces within the canister model. Finally, canister simulations with helium pressures of 100 and 400 Pa and α = 1, 0.4, and 0.2 are performed to determine how much hotter the fuel cladding is under vacuum-drying conditions compared to atmospheric pressure. For α = 0.4, the fuel heat generation rates that bring the clad temperature to its allowed limit for helium pressures of 400 and 100 Pa are reduced by 10% and 25%, respectively, compared to atmospheric pressure conditions. Transient simulations show that the cladding reaches its steady-state temperatures ~20 to 30 h after water is removed from the canister.