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The division was organized to promote the advancement of knowledge of the use of particle accelerator technologies for nuclear and other applications. It focuses on production of neutrons and other particles, utilization of these particles for scientific or industrial purposes, such as the production or destruction of radionuclides significant to energy, medicine, defense or other endeavors, as well as imaging and diagnostics.
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ANS Student Conference 2025
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General Kenneth Nichols and the Manhattan Project
Nichols
The Oak Ridger has published the latest in a series of articles about General Kenneth D. Nichols, the Manhattan Project, and the 1954 Atomic Energy Act. The series has been produced by Nichols’ grandniece Barbara Rogers Scollin and Oak Ridge (Tenn.) city historian David Ray Smith. Gen. Nichols (1907–2000) was the district engineer for the Manhattan Engineer District during the Manhattan Project.
As Smith and Scollin explain, Nichols “had supervision of the research and development connected with, and the design, construction, and operation of, all plants required to produce plutonium-239 and uranium-235, including the construction of the towns of Oak Ridge, Tennessee, and Richland, Washington. The responsibility of his position was massive as he oversaw a workforce of both military and civilian personnel of approximately 125,000; his Oak Ridge office became the center of the wartime atomic energy’s activities.”
Larry G. Blackwood, Yale D. Harker
Nuclear Technology | Volume 132 | Number 3 | December 2000 | Pages 366-374
Technical Paper | Reactor Safety | doi.org/10.13182/NT00-A3150
Articles are hosted by Taylor and Francis Online.
Current nuclear criticality safety limit requirements for transporting TRUPACT-II waste containers to the U.S. Department of Energy's Waste Isolation Pilot Plant (WIPP) specify that the 239Pu fissile gram equivalent (FGE) plus two times its measurement error must be 325 g for a payload of fourteen 55-gal drums. The authorized method for calculating a TRUPACT-II FGE measurement error value is to take the square root of the sum of the squared error values for the individual containers (often called root-sum-squares or simply RSS). However, to the extent that the individual drum measurements contain common bias effects (e.g., due to common calibration or other adjustment factors), the corresponding measurement errors are correlated, and simple RSS calculations will underestimate the true error in the TRUPACT-II FGE value.The RSS calculations assume independence, while common bias effects can induce strong correlations between the errors in measurements. Significant bias effects can occur when the matrix characteristics for a particular waste type are not fully accounted for in the measurement process. Depending on the relative size of the bias error compared to precision error, the true measurement error can be greater than twice that calculated by RSS. In such cases, the FGE shipping requirement may not be met. To avoid underestimating the error, bias components should be estimated and propagated separately (combined only at the final step in the TRUPACT-II FGE calculation), or the effect of bias on covariance between measurements must be calculated. These covariance terms then need to be included in the final uncertainty calculations.