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Book Critical Assemblies of Uranium Metal

Download or read book Critical Assemblies of Uranium Metal written by R. Gwin and published by . This book was released on 1959 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book CRITICAL ASSEMBLIES OF URANIUM METAL

Download or read book CRITICAL ASSEMBLIES OF URANIUM METAL written by and published by . This book was released on 1959 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Data on critical assemblies of fissionable uranium metals are summarized. Empirical studies are made for spccific reflectors and gcometrics to determine the fcasibility of extrapolating these data for conditions concerning nuclcear safcty problems. Also included are the influencs on critical systems by various reficctors, U-235 isotopic enrichment, density, and small metal pieces homogcncously distributed in water. (auth).

Book Critical Assembly of Uranium Metal at an Average U sup 235 Concentration of 16 1 4

Download or read book Critical Assembly of Uranium Metal at an Average U sup 235 Concentration of 16 1 4 written by and published by . This book was released on 1956 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A uranium metal critical assembly consisted of a 15-in. diameter core with an average U/sup 235/ content of 161/4%, surrounded by a 3-in. thick natural uranium reflector. The critical mass was 692 kg of core material. (auth).

Book Critical Assembly

    Critical Assembly

    Book Details:
  • Author : Lillian Hoddeson
  • Publisher : Cambridge University Press
  • Release : 2004-02-12
  • ISBN : 9780521541176
  • Pages : 532 pages

Download or read book Critical Assembly written by Lillian Hoddeson and published by Cambridge University Press. This book was released on 2004-02-12 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt: This 1993 book explores how the 'critical assembly' of scientists at Los Alamos created the first atomic bombs.

Book Consistent P1 Analysis of Aqueous Uranium 235 Critical Assemblies

Download or read book Consistent P1 Analysis of Aqueous Uranium 235 Critical Assemblies written by Daniel Fieno and published by . This book was released on 1961 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book A URANIUM CRITICAL ASSEMBLY AT LOW U sup 235 CONCENTRATION

Download or read book A URANIUM CRITICAL ASSEMBLY AT LOW U sup 235 CONCENTRATION written by and published by . This book was released on 1956 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A critical metal assembly is described that has a cylindrical core of uranium with an average U/sup 235/ concentration of 161/4% and a 3 inch reflector of natural uranium. The critical mass was determined to be 692 plus or minus 4 kg of core material, from which a value for the critical mass of a bare sphere, having the same concentration, is calculated. Measurements of the prompt neutron decay constant, reactivity contributions of several materials, and radial and axial variations of fission rates of U/sup 235/ U/sup 238/ and Np/sup 237/ as well as ratios of fission cross sections for these isotopes, are reported. (auth).

Book Extrapolated Experimental Critical Parameters of Unreflected and Steel reflected Massive Enriched Uranium Metal Spherical and Hemispherical Assemblies

Download or read book Extrapolated Experimental Critical Parameters of Unreflected and Steel reflected Massive Enriched Uranium Metal Spherical and Hemispherical Assemblies written by and published by . This book was released on 1997 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sixty-nine critical configurations of up to 186 kg of uranium are reported from very early experiments (1960s) performed at the Rocky Flats Critical Mass Laboratory near Denver, Colorado. Enriched (93%) uranium metal spherical and hemispherical configurations were studied. All were thick-walled shells except for two solid hemispheres. Experiments were essentially unreflected; or they included central and/or external regions of mild steel. No liquids were involved. Critical parameters are derived from extrapolations beyond subcritical data. Extrapolations, rather than more precise interpolations between slightly supercritical and slightly subcritical configurations, were necessary because experiments involved manually assembled configurations. Many extrapolations were quite long; but the general lack of curvature in the subcritical region lends credibility to their validity. In addition to delayed critical parameters, a procedure is offered which might permit the determination of prompt critical parameters as well for the same cases. This conjectured procedure is not based on any strong physical arguments.

Book Two Delayed Critical Uranium 93 2 Metal Cylindrical Annuli with Central Be Moderation

Download or read book Two Delayed Critical Uranium 93 2 Metal Cylindrical Annuli with Central Be Moderation written by and published by . This book was released on 1997 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two cylindrical annuli of uranium metal were assembled to delayed criticality in 1963 with beryllium metal in the center to study the effects of beryllium to provide data for verification of neutron transport theory methods including cross section data for criticality safety calculations. These systems were assembled on a vertical assembly machine in the East cell of the Oak Ridge Critical Experiments Facility. The annuli was divided into two halves with the upper fixed half supported by a 0.010-in-thick, 30-in-diam stainless steel (type 304) diaphragm. The lower half which was hydraulically movable was supported on a very low mass tower consisting of mainly three 0.125-in-thick vertical pieces 120° apart. These systems, when assembled to delayed criticality, were located in 35 x 35 x 30 ft. high experimental room, 11.7 ft from the 5-ft-thick West wall, 12.7 ft. from the 2-ft-thick North wall and 9.2 ft. above the concrete floor. When assembled the positive reactor period measured was +403 sec for the nominal 15-in-OD assembly and +31 sec for nominal 13-in-OD assembly. The reactivity effects of nearby materials such as the support ring (+) for the diaphragm, the diaphragm ( - ) and the lower support stand(+) were evaluated. The total reactivity worths of the nearby support materials were 8.9 and 5.4 cents for the 15-in-OD and 13-in-OD assemblies, respectively. The reactivity effect of each of the components was measured for the nominal 13-in-OD assembly and they were -11.2 cents for the diaphragm, +4.4 cents for the support ring, and +12.2 cents for the support stand.

Book Highly Enriched Uranium Metal Cylinders Surrounded by Various Reflector Materials

Download or read book Highly Enriched Uranium Metal Cylinders Surrounded by Various Reflector Materials written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A series of experiments was performed at Los Alamos Scientific Laboratory in 1958 to determine critical masses of cylinders of Oralloy (Oy) reflected by a number of materials. The experiments were all performed on the Comet Universal Critical Assembly Machine, and consisted of discs of highly enriched uranium (93.3 wt.% 235U) reflected by half-inch and one-inch-thick cylindrical shells of various reflector materials. The experiments were performed by members of Group N-2, particularly K.W. Gallup, G.E. Hansen, H.C. Paxton, and R.H. White. This experiment was intended to ascertain critical masses for criticality safety purposes, as well as to compare neutron transport cross sections to those obtained from danger coefficient measurements with the Topsy Oralloy-Tuballoy reflected and Godiva unreflected critical assemblies. The reflector materials examined in this series of experiments are as follows: magnesium, titanium, aluminum, graphite, mild steel, nickel, copper, cobalt, molybdenum, natural uranium, tungsten, beryllium, aluminum oxide, molybdenum carbide, and polythene (polyethylene). Also included are two special configurations of composite beryllium and iron reflectors. Analyses were performed in which uncertainty associated with six different parameters was evaluated; namely, extrapolation to the uranium critical mass, uranium density, 235U enrichment, reflector density, reflector thickness, and reflector impurities. In addition to the idealizations made by the experimenters (removal of the platen and diaphragm), two simplifications were also made to the benchmark models that resulted in a small bias and additional uncertainty. First of all, since impurities in core and reflector materials are only estimated, they are not included in the benchmark models. Secondly, the room, support structure, and other possible surrounding equipment were not included in the model. Bias values that result from these two simplifications were determined and associated uncertainty in the bias values were included in the overall uncertainty in benchmark keff values. Bias values were very small, ranging from 0.0004?k low to 0.0007?k low. Overall uncertainties range from? 0.0018 to? 0.0030. Major contributors to the overall uncertainty include uncertainty in the extrapolation to the uranium critical mass and the uranium density. Results are summarized in Figure 1. Figure 1. Experimental, Benchmark-Model, and MCNP/KENO Calculated Results The 32 configurations described and evaluated under ICSBEP Identifier HEU-MET-FAST-084 are judged to be acceptable for use as criticality safety benchmark experiments and should be valuable integral benchmarks for nuclear data testing of the various reflector materials. Details of the benchmark models, uncertainty analyses, and final results are given in this paper.

Book Safety Analysis of Enriched Uranium Processing

Download or read book Safety Analysis of Enriched Uranium Processing written by H. T. Williams and published by . This book was released on 1960 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: