## Studies of epithermal neutrons in uranium, heavy water lattices

##### Author(s)

D'Ardenne, Walter Herbert; Thompson, Theos Jardin, 1918-1970; Lanning, David D.; Kaplan, Irving, 1912-
Download09755035.pdf (14.95Mb)

##### Other Contributors

Massachusetts Institute of Technology. Department of Nuclear Engineering

U.S. Atomic Energy Commission

##### Metadata

Show full item record##### Abstract

Measurements related to reactor physics parameters were made in three heavy water lattices. The three lattices studied consisted of 0.250-inch-diameter, 1.03 w/o U2 3 5 uranium fuel rods arranged in triangular arrays and spaced at 1.25, 1.75, and 2.50 inches. The following quantities were measured in each of the three lattices studied: the ratio of the average epicadmium U2 3 8 capture rate in the fuel rod to the average subcadmium U2 3 8 capture rate in the fuel rod ([sigma]28); the ratio of the average epicadmium U2 3 o fission rate in the fuel rod7 to the average subcadmium U 35 fission rate in the fuel rod (625); the ratio of the average U2 3 8 capture rate in the fuel rod to the average U2 3 5 fission rate in the fuel rod (C ); the ratio of the average U2 3 8 fission rate in the fuel rod to the average U2 3 5 fission rate in the fuel rod (628); and the effective resonance integral of U2 3 8 in a fuel rod (ER12 8 ). The results of an investigation of systematic errors associated with these measurements have-led to many changes and adjustments in the experimental techniques and procedure which have improved the general precision of the experimental results. A new method was developed to measure the ratio C * which simplified the experiment, significantly reduced the experimental uncertainty associated with the measurement, and avoided systematic errors inherent in the method used to measure C* in earlier work. The value of ER12 8 was also measured by a new method in which the results of measurements made in an epithermal flux which had a 1/E energy dependence are combined with the results of measurements made in a lattice. The experimental results were combined with theoretical results obtained from the computer programs THERMOS and GAM-I to determine the following reactor physics parameters for each of the three lattices studied: the resonance escape probability, p; the fast fission factor, E; the multiplication factor for an infinite system, k [infinity]; and the initial conversion ratio, C. Methods were developed to measure that portion of the activity of a foil which is due to neutron captures in the resonances in the activation cross section of the foil material. The resonance escape probability was determined by a new method, using the resonance activation date, in which the use of cadmium is not necessary.

##### Description

Statement of responsibility on title-page reads: W. H. D'Ardenne, T. J. Thompson, D. D. Lanning and I. Kaplan "August 24, 1964." "MIT-2344-2." Also issued as a Ph. D. thesis by the first author, MIT Dept. of Nuclear Engineering, 1964 Includes bibliographical references (leaves 167-170)

##### Date issued

1964##### Publisher

Cambridge, Mass. : Dept. of Nuclear Engineering, Massachusetts Institute of Technology, 1964

##### Series/Report no.

MIT-2344-2MITNE ; no. 53AEC research and development reportTID ; 4500