Experimental Studies of Slightly Enriched Uranium, Water Moderated Lattices - Part I: 0.600-in.-Diameter Rods

Technical Report · Sun Sep 01 04:00:00 EDT 1957

DOI:https://doi.org/10.2172/4298229· OSTI ID:4298229

Kouts, Herbert ^[1]; Sher, Rudolph ^[1]

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1. Brookhaven National Laboratory (BNL), Upton, NY (United States)

The experimental reactor physics program at Brookhaven has for the past few years been given mainly to a study of uranium-water lattices. The purpose of this undertaking has not been to provide direct design parameters for pressurized water reactor cores. Rather, it has been the intent to develop a body of experimental data which can be compared with the results of calculational schemes. Such work should help to improve the theoretical treatments to a point where design calculations of practical pressurized water reactor cores can be carried out with confidence. The first phase of this programmatic study, devoted to the static properties of clean, cold, rod fueled assemblies, is nearly finished. This work has consisted of measurements of as many features of the neutron economy as possible, for a variety of fuel rod sizes and enrichments and lattice spacings. The results of these experiments have been reported previously in internal memoranda and talks at meetings. Also, a fairly complete account of the measurements done with 0.600-in. and 0.750-in.-diameter rods was given at the Geneva conference in 1955. In the course of collecting data for reports on other rod sizes, it has been decided, for several reasons, that these older results should be re published. Most of the quantities have been re measured since 1955. The accuracy of some has thus been improved, and their values have changed slightly. Some systematic errors have been re moved, notably from the measurement and from a few determinations of B². The resonance capture experiments, begun in 1954, had led to only tentative results by 1955, and so were not reported in Geneva. These are now finished, and their implications must be included in any complete analysis of this work. Finally, a complete on all BNL rod measurements, giving all final results in one place, ought to be useful. This is Part I of the final report. Early reports gave results as interpreted through the four-factor formula. This practice is still followed here; but also the more basic data are presented in a form suitable for use with multigroup interpretations, because the design calculations for power reactors require a departure from four factor methods. Temperature coefficients, burn out, and stable fission product build-up all lead to neutron multiplication which varies from cell to cell. Furthermore, it has become standard practice to design nonuniformity into the reactor core at the beginning, for flux flattening, power flattening, or other engineering reasons (e.g., the PWR seed core). Therefore even heterogeneous cores are these days designed by multigroup methods. On the other hand, there is a wide difference in the multigroup methods used at different laboratories. Therefore, although this report is directed toward use in connection with such theoretical methods, no attempt is made to carry out the connection here to any great extent. The scope of Part I of this report is 15 lattices of 0.600-in.-diameter uranium rods. Three fuel enrichments were used; these had nominal U²³⁵ contents of 1.0%,1.15%, and 1.3%.

• Research Organization: Brookhaven National Laboratory (BNL), Upton, NY (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP); US Atomic Energy Commission (AEC)
• DOE Contract Number: AC02-76CH00016
• NSA Number: NSA-13-000125
• OSTI ID: 4298229
• Report Number(s): BNL-486
• Country of Publication: United States
• Language: English

Related Subjects

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
Brookhaven
CONFIGURATION
CRITICAL ASSEMBLIES
CRITICALITY
Criticality
Criticality Studies
DENSITY
ENRICHMENT
Enriched Uranium
Experimental Reactor Physics Program
FUEL ELEMENTS
Nuclear Criticality Safety Program (NCSP)
REACTOR CORE
RODS
THICKNESS
URANIUM 235
VOLUME
WATER MODERATOR
Water Moderated Lattices