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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.”
Sümer Şahin, Elliot B. Kennel
Nuclear Technology | Volume 107 | Number 2 | August 1994 | Pages 155-181
Technical Paper | Fission Reactor | doi.org/10.13182/NT94-A34985
Articles are hosted by Taylor and Francis Online.
A thermo-hydrodynamic-neutronic analysis is performed for a fast, uranium carbide (UC) fueled spacecraft nuclear in-core thermionic reactor. The thermo-hydrodynamic analysis shows that a hybrid thermionic spacecraft nuclear reactor can be designed for both electricity generation and nuclear thermal propulsion purposes. This reactor would deliver a thermal thrust ∼5000 N by a specific impulse of 670 s at a hydrogen exit temperature ∼1900K. During the nuclear thermal thrust phase, the electricity generation will drop, depending on the entry temperature of the hydrogen propellant. Fresh hydrogen can be preheated through nozzle cooling up to 1000 K or more before entering the reactor. The hydrogen pressure and velocity at reactor entry are selected p = 30 atm and ν = 200 m/s, respectively. The pressure drop along the reactor core height (= 35 cm) is calculated Δp = 8.59 atm. The neutronic analysis has been conducted in S8-P3 approximation with the help of one- and two-dimensional neutron transport codes ANISN and DORT, respectively. The calculations have shown that a UC fueled electricity generating single mode thermionic nuclear reactor can be designed to be extremely compact because of the high atomic density of the nuclear fuel (by 95 % sintering density), namely, with a core radius of 8.7 cm and core height of 25 cm, leading to power levels as low as 5 kW(electric) by an electrical output on an emitter surface of 1.243 W/cm2. A reactor control with boronated reflector drums at the outer periphery of the radial reflector of 16-cm thickness would make possible reactivity changes of Δkeff > 10%—amply sufficient for a fast reactor—without a significant distortion of the fission power profile during all phases of the space mission. The hybrid thermionic spacecraft nuclear reactor mode contains cooling channels in the nuclear fuel for the hydrogen propellant. This increases the critical reactor size because of the lower uranium atomic density in this design concept. Calculations have lead to a reactor with a core radius of 22 cm and core height of 35 cm leading to power levels ∼50 kW(electric) under the aforementioned thermionic conversion conditions.
