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Isotopes & Radiation
Members are devoted to applying nuclear science and engineering technologies involving isotopes, radiation applications, and associated equipment in scientific research, development, and industrial processes. Their interests lie primarily in education, industrial uses, biology, medicine, and health physics. Division committees include Analytical Applications of Isotopes and Radiation, Biology and Medicine, Radiation Applications, Radiation Sources and Detection, and Thermal Power Sources.
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ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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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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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.”
Robert E. Rothe, Donald L. Alvarez, Harold E. Clark
Nuclear Technology | Volume 25 | Number 3 | March 1975 | Pages 502-516
Technical Paper | Chemical Processing | doi.org/10.13182/NT75-A24388
Articles are hosted by Taylor and Francis Online.
Nuclear safety engineers must evaluate the criticality potential of a variety of plant problems. Many of these involve an essentially unreflected system containing uranium solution and a fixed nuclear poison. Measured critical parameters for such a system at solution concentrations of 52.2- and 141.5-g U/liter, together with those reported previously at 450.8-g U/liter, provide the engineer information over a wide range of concentrations normally encountered in industrial applications. The uranium was enriched to 93.24 wt% 235U. The fixed poison was 1.02 wt% natural boron alloyed in stainless-steel plates. Critical solution heights were measured for various numbers of nearly uniformly spaced vertical plates within the 106.6-cm-diam experimental tank. The simplest cases studied involved no poison, resulting in low critical heights. As plates were added, the critical height increased until a sufficient number were present that even an infinitely tall tank would have been subcritical. The actual finite plate height permitted a third type of experimental result: the critical parameters of an unpoisoned uranium solution slab on top of a highly poisoned solution region. Experimental data at all three concentrations compared with results from Monte Carlo and neutron transport computer codes are found to predict critical heights consistently in excess of measured values. A nuclear safety engineer may safely apply these calculational methods to similar plant situations provided an ∼20% reduction in either the solution height or plate spacing— whichever is appropriate—is made to account for the theory/experiment difference. Boron-containing plates are compared with borosilicate glass Raschig rings as fixed nuclear poisons for large-volume solution storage. Neither is clearly superior to the other considering the poison volume percent required for criticality. Nuclear safety engineers may safely apply these experimental poison plate data to standard ringpoisoned systems involving a high-concentration uranium solution provided a 2% increase in the boron density is made to account for uncertainties in the comparison.