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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.”
Paul B. Parks, Marshall N. Rosenbluth, Sergei V. Putvinski, Todd E. Evans
Fusion Science and Technology | Volume 35 | Number 3 | May 1999 | Pages 267-279
Technical Paper | doi.org/10.13182/FST99-A80
Articles are hosted by Taylor and Francis Online.
Proposed is a new concept for disruption mitigation and fast shutdown in tokamaks: the injection of hydrogen or helium liquid jets. Liquid jets can rapidly cool the plasma to reduce divertor heat loads and large halo current forces while simultaneously raising the density sufficiently to prevent runaway electron generation. Massive ~40- to 100-fold density increases equivalent to ~50 g of deuterium are necessary for this purpose in the International Thermonuclear Experimental Reactor (ITER). It is shown that only two or three simultaneously injected high-velocity (800 to 1200 m/s) jets can easily deliver this amount of fuel within a period of ~20 ms and thus avoid runaway electron buildup during the 50- to 500-ms current quench phase. Optimum jet parameters, such as radius, velocity, driving pressure, and injection time, predicted from a jet ablation/penetration model, lead to an innovative pulsed injector design concept. The design concept is also based on a thermodynamic process path that allows the lowest possible temperature at the nozzle orifice, given the constraint of a high, ~700-atm driving pressure. By having a cold jet exit the nozzle orifice, the potential problem of rapid boiling (flashover) during jet propagation across vacuum space between the nozzle orifice and the tokamak plasma can be overcome. A one-dimensional fluid-dynamic calculation, including finite compressibility, shows that a specially designed liquid Laval nozzle is needed for liquid helium injection because the jet velocity is supersonic (Mach number ~4). This injector concept is being considered for a proposed disruption mitigation experiment on DIII-D.