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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.”
Mark S. Jarzemba
Nuclear Technology | Volume 124 | Number 1 | October 1998 | Pages 82-87
Technical Paper | Reprocessing | doi.org/10.13182/NT98-A2910
Articles are hosted by Taylor and Francis Online.
A method is described to estimate the heat generation rate of various high-level waste (HLW) forms composed primarily of either a sludge (with a composition similar to that in the Hanford HLW tanks) or borosilicate glass. The main heat source is from radioactive decay and subsequent self-absorption of particles emitted from 137Cs, 90Sr, or their radioactive daughters contained in the waste form. The heat generation rate of the waste form is usually an important parameter in safety and performance assessments and will likely be a part of the specifications required for the vitrified waste. The heat generation rate depends on the size of the waste because larger waste forms will tend to absorb a greater fraction of the gamma radiation from 137mBa decays (a short-lived radioactive daughter of 137Cs). Because beta radiation from these two nuclides is short ranged (only a few tenths of a millimetre in water), assumption of complete self-absorption of beta radiation is justifiable. Previous work in this area estimated upper and lower bounds for the volume-averaged heat generation rate per litre of waste based on total (i.e., large-sized waste forms) and zero (i.e., small-sized waste forms) self-absorption of gamma radiation emitted from 137mBa. This analysis extends the previous work to more adequately estimate the heat generation rate of intermediate-sized waste forms based on the composition of the waste (either borosilicate glass or a simulated sludge), and the size of the waste as characterized by the surface-area-to-volume ratio. The analyses are based on runs of the MCNP version 4A code.
