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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.”
Insoo Jun, Mohamed A. Abdou, Anil Kumar
Fusion Science and Technology | Volume 25 | Number 1 | January 1994 | Pages 51-83
Technical Paper | Blanket Engineering | doi.org/10.13182/FST94-A30236
Articles are hosted by Taylor and Francis Online.
Measured decay rates resulting from neutron irradiation of zirconium and tungsten samples in a typical fusion environment have been compared with the computed values, and the sources of errors in the data and the calculational method have been identified. Comparison of four codes showed large differences that arise mainly from differences in the data libraries provided with these codes. The following reactions were found to be most important in terms of their contribution to the decay photon emission rate: 90Zr(n, 2n)-89m+gZr) 90Zr(n,p)90mY, 90Zr(n,α)87mSr, 91Zr(n,p)91mY, 186W(n,y)187W, 186W(n,p)186Ta, 186W(n,np)(n,d)-185Ta, 184W(n,p)184Ta, 183W(n,p)183Ta, 182W(n,p)-182Ta, and 186W(n, α)183Hf. However, decay data and cross sections for these reactions are not adequate in currently available libraries. An effort was made to improve the decay data by using the values from the most recent Table of Radioactive Isotopes and to improve the cross sections by using a simple curve-fitting procedure. Modified or improved decay data and cross sections were implemented in a representative code, and the computation was performed again. A great improvement in the computed results was observed for both sample cases. This work can easily be extended to other fusion-relevant materials by utilizing the methodology presented here. The improved decay and cross-section data were applied to an International Thermonuclear Experimental Reactor (ITER) blanket using tungsten as a first-wall coating material and Li2ZrO3 as a breeding material. The specific photon yield in each zone was computed, and as much as three orders of magnitude difference in the photon yield in the tungsten zone and ∼10 to 15% difference in the zirconium-containing breeding zone were observed between the results using the improved decay and cross-section data and those using the original data.
